#include #include #include #include #include "putty.h" #include "tree234.h" #include "ssh.h" #ifndef FALSE #define FALSE 0 #endif #ifndef TRUE #define TRUE 1 #endif #define SSH1_MSG_DISCONNECT 1 /* 0x1 */ #define SSH1_SMSG_PUBLIC_KEY 2 /* 0x2 */ #define SSH1_CMSG_SESSION_KEY 3 /* 0x3 */ #define SSH1_CMSG_USER 4 /* 0x4 */ #define SSH1_CMSG_AUTH_RSA 6 /* 0x6 */ #define SSH1_SMSG_AUTH_RSA_CHALLENGE 7 /* 0x7 */ #define SSH1_CMSG_AUTH_RSA_RESPONSE 8 /* 0x8 */ #define SSH1_CMSG_AUTH_PASSWORD 9 /* 0x9 */ #define SSH1_CMSG_REQUEST_PTY 10 /* 0xa */ #define SSH1_CMSG_WINDOW_SIZE 11 /* 0xb */ #define SSH1_CMSG_EXEC_SHELL 12 /* 0xc */ #define SSH1_CMSG_EXEC_CMD 13 /* 0xd */ #define SSH1_SMSG_SUCCESS 14 /* 0xe */ #define SSH1_SMSG_FAILURE 15 /* 0xf */ #define SSH1_CMSG_STDIN_DATA 16 /* 0x10 */ #define SSH1_SMSG_STDOUT_DATA 17 /* 0x11 */ #define SSH1_SMSG_STDERR_DATA 18 /* 0x12 */ #define SSH1_CMSG_EOF 19 /* 0x13 */ #define SSH1_SMSG_EXIT_STATUS 20 /* 0x14 */ #define SSH1_MSG_CHANNEL_OPEN_CONFIRMATION 21 /* 0x15 */ #define SSH1_MSG_CHANNEL_OPEN_FAILURE 22 /* 0x16 */ #define SSH1_MSG_CHANNEL_DATA 23 /* 0x17 */ #define SSH1_MSG_CHANNEL_CLOSE 24 /* 0x18 */ #define SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION 25 /* 0x19 */ #define SSH1_SMSG_X11_OPEN 27 /* 0x1b */ #define SSH1_CMSG_PORT_FORWARD_REQUEST 28 /* 0x1c */ #define SSH1_MSG_PORT_OPEN 29 /* 0x1d */ #define SSH1_CMSG_AGENT_REQUEST_FORWARDING 30 /* 0x1e */ #define SSH1_SMSG_AGENT_OPEN 31 /* 0x1f */ #define SSH1_MSG_IGNORE 32 /* 0x20 */ #define SSH1_CMSG_EXIT_CONFIRMATION 33 /* 0x21 */ #define SSH1_CMSG_X11_REQUEST_FORWARDING 34 /* 0x22 */ #define SSH1_CMSG_AUTH_RHOSTS_RSA 35 /* 0x23 */ #define SSH1_MSG_DEBUG 36 /* 0x24 */ #define SSH1_CMSG_REQUEST_COMPRESSION 37 /* 0x25 */ #define SSH1_CMSG_AUTH_TIS 39 /* 0x27 */ #define SSH1_SMSG_AUTH_TIS_CHALLENGE 40 /* 0x28 */ #define SSH1_CMSG_AUTH_TIS_RESPONSE 41 /* 0x29 */ #define SSH1_CMSG_AUTH_CCARD 70 /* 0x46 */ #define SSH1_SMSG_AUTH_CCARD_CHALLENGE 71 /* 0x47 */ #define SSH1_CMSG_AUTH_CCARD_RESPONSE 72 /* 0x48 */ #define SSH1_AUTH_TIS 5 /* 0x5 */ #define SSH1_AUTH_CCARD 16 /* 0x10 */ #define SSH1_PROTOFLAG_SCREEN_NUMBER 1 /* 0x1 */ /* Mask for protoflags we will echo back to server if seen */ #define SSH1_PROTOFLAGS_SUPPORTED 0 /* 0x1 */ #define SSH2_MSG_DISCONNECT 1 /* 0x1 */ #define SSH2_MSG_IGNORE 2 /* 0x2 */ #define SSH2_MSG_UNIMPLEMENTED 3 /* 0x3 */ #define SSH2_MSG_DEBUG 4 /* 0x4 */ #define SSH2_MSG_SERVICE_REQUEST 5 /* 0x5 */ #define SSH2_MSG_SERVICE_ACCEPT 6 /* 0x6 */ #define SSH2_MSG_KEXINIT 20 /* 0x14 */ #define SSH2_MSG_NEWKEYS 21 /* 0x15 */ #define SSH2_MSG_KEXDH_INIT 30 /* 0x1e */ #define SSH2_MSG_KEXDH_REPLY 31 /* 0x1f */ #define SSH2_MSG_KEX_DH_GEX_REQUEST 30 /* 0x1e */ #define SSH2_MSG_KEX_DH_GEX_GROUP 31 /* 0x1f */ #define SSH2_MSG_KEX_DH_GEX_INIT 32 /* 0x20 */ #define SSH2_MSG_KEX_DH_GEX_REPLY 33 /* 0x21 */ #define SSH2_MSG_USERAUTH_REQUEST 50 /* 0x32 */ #define SSH2_MSG_USERAUTH_FAILURE 51 /* 0x33 */ #define SSH2_MSG_USERAUTH_SUCCESS 52 /* 0x34 */ #define SSH2_MSG_USERAUTH_BANNER 53 /* 0x35 */ #define SSH2_MSG_USERAUTH_PK_OK 60 /* 0x3c */ #define SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ 60 /* 0x3c */ #define SSH2_MSG_USERAUTH_INFO_REQUEST 60 /* 0x3c */ #define SSH2_MSG_USERAUTH_INFO_RESPONSE 61 /* 0x3d */ #define SSH2_MSG_GLOBAL_REQUEST 80 /* 0x50 */ #define SSH2_MSG_REQUEST_SUCCESS 81 /* 0x51 */ #define SSH2_MSG_REQUEST_FAILURE 82 /* 0x52 */ #define SSH2_MSG_CHANNEL_OPEN 90 /* 0x5a */ #define SSH2_MSG_CHANNEL_OPEN_CONFIRMATION 91 /* 0x5b */ #define SSH2_MSG_CHANNEL_OPEN_FAILURE 92 /* 0x5c */ #define SSH2_MSG_CHANNEL_WINDOW_ADJUST 93 /* 0x5d */ #define SSH2_MSG_CHANNEL_DATA 94 /* 0x5e */ #define SSH2_MSG_CHANNEL_EXTENDED_DATA 95 /* 0x5f */ #define SSH2_MSG_CHANNEL_EOF 96 /* 0x60 */ #define SSH2_MSG_CHANNEL_CLOSE 97 /* 0x61 */ #define SSH2_MSG_CHANNEL_REQUEST 98 /* 0x62 */ #define SSH2_MSG_CHANNEL_SUCCESS 99 /* 0x63 */ #define SSH2_MSG_CHANNEL_FAILURE 100 /* 0x64 */ /* * Packet type contexts, so that ssh2_pkt_type can correctly decode * the ambiguous type numbers back into the correct type strings. */ #define SSH2_PKTCTX_DHGROUP 0x0001 #define SSH2_PKTCTX_DHGEX 0x0002 #define SSH2_PKTCTX_KEX_MASK 0x000F #define SSH2_PKTCTX_PUBLICKEY 0x0010 #define SSH2_PKTCTX_PASSWORD 0x0020 #define SSH2_PKTCTX_KBDINTER 0x0040 #define SSH2_PKTCTX_AUTH_MASK 0x00F0 #define SSH2_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT 1 /* 0x1 */ #define SSH2_DISCONNECT_PROTOCOL_ERROR 2 /* 0x2 */ #define SSH2_DISCONNECT_KEY_EXCHANGE_FAILED 3 /* 0x3 */ #define SSH2_DISCONNECT_HOST_AUTHENTICATION_FAILED 4 /* 0x4 */ #define SSH2_DISCONNECT_MAC_ERROR 5 /* 0x5 */ #define SSH2_DISCONNECT_COMPRESSION_ERROR 6 /* 0x6 */ #define SSH2_DISCONNECT_SERVICE_NOT_AVAILABLE 7 /* 0x7 */ #define SSH2_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED 8 /* 0x8 */ #define SSH2_DISCONNECT_HOST_KEY_NOT_VERIFIABLE 9 /* 0x9 */ #define SSH2_DISCONNECT_CONNECTION_LOST 10 /* 0xa */ #define SSH2_DISCONNECT_BY_APPLICATION 11 /* 0xb */ #define SSH2_DISCONNECT_TOO_MANY_CONNECTIONS 12 /* 0xc */ #define SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER 13 /* 0xd */ #define SSH2_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE 14 /* 0xe */ #define SSH2_DISCONNECT_ILLEGAL_USER_NAME 15 /* 0xf */ static const char *const ssh2_disconnect_reasons[] = { NULL, "SSH_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT", "SSH_DISCONNECT_PROTOCOL_ERROR", "SSH_DISCONNECT_KEY_EXCHANGE_FAILED", "SSH_DISCONNECT_HOST_AUTHENTICATION_FAILED", "SSH_DISCONNECT_MAC_ERROR", "SSH_DISCONNECT_COMPRESSION_ERROR", "SSH_DISCONNECT_SERVICE_NOT_AVAILABLE", "SSH_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED", "SSH_DISCONNECT_HOST_KEY_NOT_VERIFIABLE", "SSH_DISCONNECT_CONNECTION_LOST", "SSH_DISCONNECT_BY_APPLICATION", "SSH_DISCONNECT_TOO_MANY_CONNECTIONS", "SSH_DISCONNECT_AUTH_CANCELLED_BY_USER", "SSH_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE", "SSH_DISCONNECT_ILLEGAL_USER_NAME", }; #define SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED 1 /* 0x1 */ #define SSH2_OPEN_CONNECT_FAILED 2 /* 0x2 */ #define SSH2_OPEN_UNKNOWN_CHANNEL_TYPE 3 /* 0x3 */ #define SSH2_OPEN_RESOURCE_SHORTAGE 4 /* 0x4 */ #define SSH2_EXTENDED_DATA_STDERR 1 /* 0x1 */ /* * Various remote-bug flags. */ #define BUG_CHOKES_ON_SSH1_IGNORE 1 #define BUG_SSH2_HMAC 2 #define BUG_NEEDS_SSH1_PLAIN_PASSWORD 4 #define BUG_CHOKES_ON_RSA 8 #define BUG_SSH2_RSA_PADDING 16 #define BUG_SSH2_DERIVEKEY 32 #define BUG_SSH2_REKEY 64 #define BUG_SSH2_PK_SESSIONID 128 #define translate(x) if (type == x) return #x #define translatec(x,ctx) if (type == x && (pkt_ctx & ctx)) return #x static char *ssh1_pkt_type(int type) { translate(SSH1_MSG_DISCONNECT); translate(SSH1_SMSG_PUBLIC_KEY); translate(SSH1_CMSG_SESSION_KEY); translate(SSH1_CMSG_USER); translate(SSH1_CMSG_AUTH_RSA); translate(SSH1_SMSG_AUTH_RSA_CHALLENGE); translate(SSH1_CMSG_AUTH_RSA_RESPONSE); translate(SSH1_CMSG_AUTH_PASSWORD); translate(SSH1_CMSG_REQUEST_PTY); translate(SSH1_CMSG_WINDOW_SIZE); translate(SSH1_CMSG_EXEC_SHELL); translate(SSH1_CMSG_EXEC_CMD); translate(SSH1_SMSG_SUCCESS); translate(SSH1_SMSG_FAILURE); translate(SSH1_CMSG_STDIN_DATA); translate(SSH1_SMSG_STDOUT_DATA); translate(SSH1_SMSG_STDERR_DATA); translate(SSH1_CMSG_EOF); translate(SSH1_SMSG_EXIT_STATUS); translate(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION); translate(SSH1_MSG_CHANNEL_OPEN_FAILURE); translate(SSH1_MSG_CHANNEL_DATA); translate(SSH1_MSG_CHANNEL_CLOSE); translate(SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION); translate(SSH1_SMSG_X11_OPEN); translate(SSH1_CMSG_PORT_FORWARD_REQUEST); translate(SSH1_MSG_PORT_OPEN); translate(SSH1_CMSG_AGENT_REQUEST_FORWARDING); translate(SSH1_SMSG_AGENT_OPEN); translate(SSH1_MSG_IGNORE); translate(SSH1_CMSG_EXIT_CONFIRMATION); translate(SSH1_CMSG_X11_REQUEST_FORWARDING); translate(SSH1_CMSG_AUTH_RHOSTS_RSA); translate(SSH1_MSG_DEBUG); translate(SSH1_CMSG_REQUEST_COMPRESSION); translate(SSH1_CMSG_AUTH_TIS); translate(SSH1_SMSG_AUTH_TIS_CHALLENGE); translate(SSH1_CMSG_AUTH_TIS_RESPONSE); translate(SSH1_CMSG_AUTH_CCARD); translate(SSH1_SMSG_AUTH_CCARD_CHALLENGE); translate(SSH1_CMSG_AUTH_CCARD_RESPONSE); return "unknown"; } static char *ssh2_pkt_type(int pkt_ctx, int type) { translate(SSH2_MSG_DISCONNECT); translate(SSH2_MSG_IGNORE); translate(SSH2_MSG_UNIMPLEMENTED); translate(SSH2_MSG_DEBUG); translate(SSH2_MSG_SERVICE_REQUEST); translate(SSH2_MSG_SERVICE_ACCEPT); translate(SSH2_MSG_KEXINIT); translate(SSH2_MSG_NEWKEYS); translatec(SSH2_MSG_KEXDH_INIT, SSH2_PKTCTX_DHGROUP); translatec(SSH2_MSG_KEXDH_REPLY, SSH2_PKTCTX_DHGROUP); translatec(SSH2_MSG_KEX_DH_GEX_REQUEST, SSH2_PKTCTX_DHGEX); translatec(SSH2_MSG_KEX_DH_GEX_GROUP, SSH2_PKTCTX_DHGEX); translatec(SSH2_MSG_KEX_DH_GEX_INIT, SSH2_PKTCTX_DHGEX); translatec(SSH2_MSG_KEX_DH_GEX_REPLY, SSH2_PKTCTX_DHGEX); translate(SSH2_MSG_USERAUTH_REQUEST); translate(SSH2_MSG_USERAUTH_FAILURE); translate(SSH2_MSG_USERAUTH_SUCCESS); translate(SSH2_MSG_USERAUTH_BANNER); translatec(SSH2_MSG_USERAUTH_PK_OK, SSH2_PKTCTX_PUBLICKEY); translatec(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, SSH2_PKTCTX_PASSWORD); translatec(SSH2_MSG_USERAUTH_INFO_REQUEST, SSH2_PKTCTX_KBDINTER); translatec(SSH2_MSG_USERAUTH_INFO_RESPONSE, SSH2_PKTCTX_KBDINTER); translate(SSH2_MSG_GLOBAL_REQUEST); translate(SSH2_MSG_REQUEST_SUCCESS); translate(SSH2_MSG_REQUEST_FAILURE); translate(SSH2_MSG_CHANNEL_OPEN); translate(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); translate(SSH2_MSG_CHANNEL_OPEN_FAILURE); translate(SSH2_MSG_CHANNEL_WINDOW_ADJUST); translate(SSH2_MSG_CHANNEL_DATA); translate(SSH2_MSG_CHANNEL_EXTENDED_DATA); translate(SSH2_MSG_CHANNEL_EOF); translate(SSH2_MSG_CHANNEL_CLOSE); translate(SSH2_MSG_CHANNEL_REQUEST); translate(SSH2_MSG_CHANNEL_SUCCESS); translate(SSH2_MSG_CHANNEL_FAILURE); return "unknown"; } #undef translate #undef translatec #define GET_32BIT(cp) \ (((unsigned long)(unsigned char)(cp)[0] << 24) | \ ((unsigned long)(unsigned char)(cp)[1] << 16) | \ ((unsigned long)(unsigned char)(cp)[2] << 8) | \ ((unsigned long)(unsigned char)(cp)[3])) #define PUT_32BIT(cp, value) { \ (cp)[0] = (unsigned char)((value) >> 24); \ (cp)[1] = (unsigned char)((value) >> 16); \ (cp)[2] = (unsigned char)((value) >> 8); \ (cp)[3] = (unsigned char)(value); } /* Enumeration values for fields in SSH-1 packets */ enum { PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR, PKT_BIGNUM, /* These values are for communicating relevant semantics of * fields to the packet logging code. */ PKTT_OTHER, PKTT_PASSWORD, PKTT_DATA }; /* * Coroutine mechanics for the sillier bits of the code. If these * macros look impenetrable to you, you might find it helpful to * read * * http://www.chiark.greenend.org.uk/~sgtatham/coroutines.html * * which explains the theory behind these macros. * * In particular, if you are getting `case expression not constant' * errors when building with MS Visual Studio, this is because MS's * Edit and Continue debugging feature causes their compiler to * violate ANSI C. To disable Edit and Continue debugging: * * - right-click ssh.c in the FileView * - click Settings * - select the C/C++ tab and the General category * - under `Debug info:', select anything _other_ than `Program * Database for Edit and Continue'. */ #define crBegin(v) { int *crLine = &v; switch(v) { case 0:; #define crState(t) \ struct t *s; \ if (!ssh->t) ssh->t = snew(struct t); \ s = ssh->t; #define crFinish(z) } *crLine = 0; return (z); } #define crFinishV } *crLine = 0; return; } #define crReturn(z) \ do {\ *crLine =__LINE__; return (z); case __LINE__:;\ } while (0) #define crReturnV \ do {\ *crLine=__LINE__; return; case __LINE__:;\ } while (0) #define crStop(z) do{ *crLine = 0; return (z); }while(0) #define crStopV do{ *crLine = 0; return; }while(0) #define crWaitUntil(c) do { crReturn(0); } while (!(c)) #define crWaitUntilV(c) do { crReturnV; } while (!(c)) typedef struct ssh_tag *Ssh; struct Packet; static struct Packet *ssh2_pkt_init(int pkt_type); static void ssh2_pkt_addbool(struct Packet *, unsigned char value); static void ssh2_pkt_adduint32(struct Packet *, unsigned long value); static void ssh2_pkt_addstring_start(struct Packet *); static void ssh2_pkt_addstring_str(struct Packet *, char *data); static void ssh2_pkt_addstring_data(struct Packet *, char *data, int len); static void ssh2_pkt_addstring(struct Packet *, char *data); static unsigned char *ssh2_mpint_fmt(Bignum b, int *len); static void ssh2_pkt_addmp(struct Packet *, Bignum b); static int ssh2_pkt_construct(Ssh, struct Packet *); static void ssh2_pkt_send(Ssh, struct Packet *); static void ssh2_pkt_send_noqueue(Ssh, struct Packet *); static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, struct Packet *pktin); static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, struct Packet *pktin); /* * Buffer management constants. There are several of these for * various different purposes: * * - SSH1_BUFFER_LIMIT is the amount of backlog that must build up * on a local data stream before we throttle the whole SSH * connection (in SSH-1 only). Throttling the whole connection is * pretty drastic so we set this high in the hope it won't * happen very often. * * - SSH_MAX_BACKLOG is the amount of backlog that must build up * on the SSH connection itself before we defensively throttle * _all_ local data streams. This is pretty drastic too (though * thankfully unlikely in SSH-2 since the window mechanism should * ensure that the server never has any need to throttle its end * of the connection), so we set this high as well. * * - OUR_V2_WINSIZE is the maximum window size we present on SSH-2 * channels. */ #define SSH1_BUFFER_LIMIT 32768 #define SSH_MAX_BACKLOG 32768 #define OUR_V2_WINSIZE 16384 #define OUR_V2_MAXPKT 0x4000UL const static struct ssh_signkey *hostkey_algs[] = { &ssh_rsa, &ssh_dss }; static void *nullmac_make_context(void) { return NULL; } static void nullmac_free_context(void *handle) { } static void nullmac_key(void *handle, unsigned char *key) { } static void nullmac_generate(void *handle, unsigned char *blk, int len, unsigned long seq) { } static int nullmac_verify(void *handle, unsigned char *blk, int len, unsigned long seq) { return 1; } const static struct ssh_mac ssh_mac_none = { nullmac_make_context, nullmac_free_context, nullmac_key, nullmac_generate, nullmac_verify, "none", 0 }; const static struct ssh_mac *macs[] = { &ssh_sha1, &ssh_md5, &ssh_mac_none }; const static struct ssh_mac *buggymacs[] = { &ssh_sha1_buggy, &ssh_md5, &ssh_mac_none }; static void *ssh_comp_none_init(void) { return NULL; } static void ssh_comp_none_cleanup(void *handle) { } static int ssh_comp_none_block(void *handle, unsigned char *block, int len, unsigned char **outblock, int *outlen) { return 0; } static int ssh_comp_none_disable(void *handle) { return 0; } const static struct ssh_compress ssh_comp_none = { "none", ssh_comp_none_init, ssh_comp_none_cleanup, ssh_comp_none_block, ssh_comp_none_init, ssh_comp_none_cleanup, ssh_comp_none_block, ssh_comp_none_disable, NULL }; extern const struct ssh_compress ssh_zlib; const static struct ssh_compress *compressions[] = { &ssh_zlib, &ssh_comp_none }; enum { /* channel types */ CHAN_MAINSESSION, CHAN_X11, CHAN_AGENT, CHAN_SOCKDATA, CHAN_SOCKDATA_DORMANT /* one the remote hasn't confirmed */ }; /* * 2-3-4 tree storing channels. */ struct ssh_channel { Ssh ssh; /* pointer back to main context */ unsigned remoteid, localid; int type; /* True if we opened this channel but server hasn't confirmed. */ int halfopen; /* * In SSH-1, this value contains four bits: * * 1 We have sent SSH1_MSG_CHANNEL_CLOSE. * 2 We have sent SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION. * 4 We have received SSH1_MSG_CHANNEL_CLOSE. * 8 We have received SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION. * * A channel is completely finished with when all four bits are set. */ int closes; union { struct ssh1_data_channel { int throttling; } v1; struct ssh2_data_channel { bufchain outbuffer; unsigned remwindow, remmaxpkt; unsigned locwindow; } v2; } v; union { struct ssh_agent_channel { unsigned char *message; unsigned char msglen[4]; unsigned lensofar, totallen; } a; struct ssh_x11_channel { Socket s; } x11; struct ssh_pfd_channel { Socket s; } pfd; } u; }; /* * 2-3-4 tree storing remote->local port forwardings. SSH-1 and SSH-2 * use this structure in different ways, reflecting SSH-2's * altogether saner approach to port forwarding. * * In SSH-1, you arrange a remote forwarding by sending the server * the remote port number, and the local destination host:port. * When a connection comes in, the server sends you back that * host:port pair, and you connect to it. This is a ready-made * security hole if you're not on the ball: a malicious server * could send you back _any_ host:port pair, so if you trustingly * connect to the address it gives you then you've just opened the * entire inside of your corporate network just by connecting * through it to a dodgy SSH server. Hence, we must store a list of * host:port pairs we _are_ trying to forward to, and reject a * connection request from the server if it's not in the list. * * In SSH-2, each side of the connection minds its own business and * doesn't send unnecessary information to the other. You arrange a * remote forwarding by sending the server just the remote port * number. When a connection comes in, the server tells you which * of its ports was connected to; and _you_ have to remember what * local host:port pair went with that port number. * * Hence, in SSH-1 this structure is indexed by destination * host:port pair, whereas in SSH-2 it is indexed by source port. */ struct ssh_portfwd; /* forward declaration */ struct ssh_rportfwd { unsigned sport, dport; char dhost[256]; char *sportdesc; struct ssh_portfwd *pfrec; }; #define free_rportfwd(pf) ( \ ((pf) ? (sfree((pf)->sportdesc)) : (void)0 ), sfree(pf) ) /* * Separately to the rportfwd tree (which is for looking up port * open requests from the server), a tree of _these_ structures is * used to keep track of all the currently open port forwardings, * so that we can reconfigure in mid-session if the user requests * it. */ struct ssh_portfwd { enum { DESTROY, KEEP, CREATE } status; int type; unsigned sport, dport; char *saddr, *daddr; char *sserv, *dserv; struct ssh_rportfwd *remote; int addressfamily; void *local; }; #define free_portfwd(pf) ( \ ((pf) ? (sfree((pf)->saddr), sfree((pf)->daddr), \ sfree((pf)->sserv), sfree((pf)->dserv)) : (void)0 ), sfree(pf) ) struct Packet { long length; long forcepad; /* Force padding to at least this length */ int type; unsigned long sequence; unsigned char *data; unsigned char *body; long savedpos; long maxlen; long encrypted_len; /* for SSH-2 total-size counting */ /* * State associated with packet logging */ int logmode; int nblanks; struct logblank_t *blanks; }; static void ssh1_protocol(Ssh ssh, void *vin, int inlen, struct Packet *pktin); static void ssh2_protocol(Ssh ssh, void *vin, int inlen, struct Packet *pktin); static void ssh1_protocol_setup(Ssh ssh); static void ssh2_protocol_setup(Ssh ssh); static void ssh_size(void *handle, int width, int height); static void ssh_special(void *handle, Telnet_Special); static int ssh2_try_send(struct ssh_channel *c); static void ssh2_add_channel_data(struct ssh_channel *c, char *buf, int len); static void ssh_throttle_all(Ssh ssh, int enable, int bufsize); static void ssh2_set_window(struct ssh_channel *c, unsigned newwin); static int ssh_sendbuffer(void *handle); static int ssh_do_close(Ssh ssh, int notify_exit); static unsigned long ssh_pkt_getuint32(struct Packet *pkt); static int ssh2_pkt_getbool(struct Packet *pkt); static void ssh_pkt_getstring(struct Packet *pkt, char **p, int *length); static void ssh2_timer(void *ctx, long now); static int do_ssh2_transport(Ssh ssh, void *vin, int inlen, struct Packet *pktin); struct rdpkt1_state_tag { long len, pad, biglen, to_read; unsigned long realcrc, gotcrc; unsigned char *p; int i; int chunk; struct Packet *pktin; }; struct rdpkt2_state_tag { long len, pad, payload, packetlen, maclen; int i; int cipherblk; unsigned long incoming_sequence; struct Packet *pktin; }; typedef void (*handler_fn_t)(Ssh ssh, struct Packet *pktin); typedef void (*chandler_fn_t)(Ssh ssh, struct Packet *pktin, void *ctx); struct queued_handler; struct queued_handler { int msg1, msg2; chandler_fn_t handler; void *ctx; struct queued_handler *next; }; struct ssh_tag { const struct plug_function_table *fn; /* the above field _must_ be first in the structure */ SHA_State exhash, exhashbase; Socket s; void *ldisc; void *logctx; unsigned char session_key[32]; int v1_compressing; int v1_remote_protoflags; int v1_local_protoflags; int agentfwd_enabled; int X11_fwd_enabled; int remote_bugs; const struct ssh_cipher *cipher; void *v1_cipher_ctx; void *crcda_ctx; const struct ssh2_cipher *cscipher, *sccipher; void *cs_cipher_ctx, *sc_cipher_ctx; const struct ssh_mac *csmac, *scmac; void *cs_mac_ctx, *sc_mac_ctx; const struct ssh_compress *cscomp, *sccomp; void *cs_comp_ctx, *sc_comp_ctx; const struct ssh_kex *kex; const struct ssh_signkey *hostkey; unsigned char v2_session_id[20]; void *kex_ctx; char *savedhost; int savedport; int send_ok; int echoing, editing; void *frontend; int ospeed, ispeed; /* temporaries */ int term_width, term_height; tree234 *channels; /* indexed by local id */ struct ssh_channel *mainchan; /* primary session channel */ int exitcode; int close_expected; tree234 *rportfwds, *portfwds; enum { SSH_STATE_PREPACKET, SSH_STATE_BEFORE_SIZE, SSH_STATE_INTERMED, SSH_STATE_SESSION, SSH_STATE_CLOSED } state; int size_needed, eof_needed; struct Packet **queue; int queuelen, queuesize; int queueing; unsigned char *deferred_send_data; int deferred_len, deferred_size; /* * Gross hack: pscp will try to start SFTP but fall back to * scp1 if that fails. This variable is the means by which * scp.c can reach into the SSH code and find out which one it * got. */ int fallback_cmd; /* * Used for username and password input. */ char *userpass_input_buffer; int userpass_input_buflen; int userpass_input_bufpos; int userpass_input_echo; int pkt_ctx; void *x11auth; int version; int v1_throttle_count; int overall_bufsize; int throttled_all; int v1_stdout_throttling; unsigned long v2_outgoing_sequence; int ssh1_rdpkt_crstate; int ssh2_rdpkt_crstate; int do_ssh_init_crstate; int ssh_gotdata_crstate; int do_ssh1_login_crstate; int do_ssh1_connection_crstate; int do_ssh2_transport_crstate; int do_ssh2_authconn_crstate; void *do_ssh_init_state; void *do_ssh1_login_state; void *do_ssh2_transport_state; void *do_ssh2_authconn_state; struct rdpkt1_state_tag rdpkt1_state; struct rdpkt2_state_tag rdpkt2_state; /* SSH-1 and SSH-2 use this for different things, but both use it */ int protocol_initial_phase_done; void (*protocol) (Ssh ssh, void *vin, int inlen, struct Packet *pkt); struct Packet *(*s_rdpkt) (Ssh ssh, unsigned char **data, int *datalen); /* * We maintain a full _copy_ of a Config structure here, not * merely a pointer to it. That way, when we're passed a new * one for reconfiguration, we can check the differences and * potentially reconfigure port forwardings etc in mid-session. */ Config cfg; /* * Used to transfer data back from async callbacks. */ void *agent_response; int agent_response_len; int user_response; /* * The SSH connection can be set as `frozen', meaning we are * not currently accepting incoming data from the network. This * is slightly more serious than setting the _socket_ as * frozen, because we may already have had data passed to us * from the network which we need to delay processing until * after the freeze is lifted, so we also need a bufchain to * store that data. */ int frozen; bufchain queued_incoming_data; /* * Dispatch table for packet types that we may have to deal * with at any time. */ handler_fn_t packet_dispatch[256]; /* * Queues of one-off handler functions for success/failure * indications from a request. */ struct queued_handler *qhead, *qtail; /* * This module deals with sending keepalives. */ Pinger pinger; /* * Track incoming and outgoing data sizes and time, for * size-based rekeys. */ unsigned long incoming_data_size, outgoing_data_size, deferred_data_size; unsigned long max_data_size; int kex_in_progress; long next_rekey, last_rekey; char *deferred_rekey_reason; /* points to STATIC string; don't free */ }; #define logevent(s) logevent(ssh->frontend, s) /* logevent, only printf-formatted. */ static void logeventf(Ssh ssh, const char *fmt, ...) { va_list ap; char *buf; va_start(ap, fmt); buf = dupvprintf(fmt, ap); va_end(ap); logevent(buf); sfree(buf); } #define bombout(msg) \ do { \ char *text = dupprintf msg; \ ssh_do_close(ssh, FALSE); \ logevent(text); \ connection_fatal(ssh->frontend, "%s", text); \ sfree(text); \ } while (0) /* Functions to leave bits out of the SSH packet log file. */ static void dont_log_password(Ssh ssh, struct Packet *pkt, int blanktype) { if (ssh->cfg.logomitpass) pkt->logmode = blanktype; } static void dont_log_data(Ssh ssh, struct Packet *pkt, int blanktype) { if (ssh->cfg.logomitdata) pkt->logmode = blanktype; } static void end_log_omission(Ssh ssh, struct Packet *pkt) { pkt->logmode = PKTLOG_EMIT; } static int ssh_channelcmp(void *av, void *bv) { struct ssh_channel *a = (struct ssh_channel *) av; struct ssh_channel *b = (struct ssh_channel *) bv; if (a->localid < b->localid) return -1; if (a->localid > b->localid) return +1; return 0; } static int ssh_channelfind(void *av, void *bv) { unsigned *a = (unsigned *) av; struct ssh_channel *b = (struct ssh_channel *) bv; if (*a < b->localid) return -1; if (*a > b->localid) return +1; return 0; } static int ssh_rportcmp_ssh1(void *av, void *bv) { struct ssh_rportfwd *a = (struct ssh_rportfwd *) av; struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv; int i; if ( (i = strcmp(a->dhost, b->dhost)) != 0) return i < 0 ? -1 : +1; if (a->dport > b->dport) return +1; if (a->dport < b->dport) return -1; return 0; } static int ssh_rportcmp_ssh2(void *av, void *bv) { struct ssh_rportfwd *a = (struct ssh_rportfwd *) av; struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv; if (a->sport > b->sport) return +1; if (a->sport < b->sport) return -1; return 0; } /* * Special form of strcmp which can cope with NULL inputs. NULL is * defined to sort before even the empty string. */ static int nullstrcmp(const char *a, const char *b) { if (a == NULL && b == NULL) return 0; if (a == NULL) return -1; if (b == NULL) return +1; return strcmp(a, b); } static int ssh_portcmp(void *av, void *bv) { struct ssh_portfwd *a = (struct ssh_portfwd *) av; struct ssh_portfwd *b = (struct ssh_portfwd *) bv; int i; if (a->type > b->type) return +1; if (a->type < b->type) return -1; if (a->addressfamily > b->addressfamily) return +1; if (a->addressfamily < b->addressfamily) return -1; if ( (i = nullstrcmp(a->saddr, b->saddr)) != 0) return i < 0 ? -1 : +1; if (a->sport > b->sport) return +1; if (a->sport < b->sport) return -1; if (a->type != 'D') { if ( (i = nullstrcmp(a->daddr, b->daddr)) != 0) return i < 0 ? -1 : +1; if (a->dport > b->dport) return +1; if (a->dport < b->dport) return -1; } return 0; } static int alloc_channel_id(Ssh ssh) { const unsigned CHANNEL_NUMBER_OFFSET = 256; unsigned low, high, mid; int tsize; struct ssh_channel *c; /* * First-fit allocation of channel numbers: always pick the * lowest unused one. To do this, binary-search using the * counted B-tree to find the largest channel ID which is in a * contiguous sequence from the beginning. (Precisely * everything in that sequence must have ID equal to its tree * index plus CHANNEL_NUMBER_OFFSET.) */ tsize = count234(ssh->channels); low = -1; high = tsize; while (high - low > 1) { mid = (high + low) / 2; c = index234(ssh->channels, mid); if (c->localid == mid + CHANNEL_NUMBER_OFFSET) low = mid; /* this one is fine */ else high = mid; /* this one is past it */ } /* * Now low points to either -1, or the tree index of the * largest ID in the initial sequence. */ { unsigned i = low + 1 + CHANNEL_NUMBER_OFFSET; assert(NULL == find234(ssh->channels, &i, ssh_channelfind)); } return low + 1 + CHANNEL_NUMBER_OFFSET; } static void c_write(Ssh ssh, const char *buf, int len) { if ((flags & FLAG_STDERR)) { int i; for (i = 0; i < len; i++) if (buf[i] != '\r') fputc(buf[i], stderr); return; } from_backend(ssh->frontend, 1, buf, len); } static void c_write_untrusted(Ssh ssh, const char *buf, int len) { int i; for (i = 0; i < len; i++) { if (buf[i] == '\n') c_write(ssh, "\r\n", 2); else if ((buf[i] & 0x60) || (buf[i] == '\r')) c_write(ssh, buf + i, 1); } } static void c_write_str(Ssh ssh, const char *buf) { c_write(ssh, buf, strlen(buf)); } static void ssh_free_packet(struct Packet *pkt) { sfree(pkt->data); sfree(pkt); } static struct Packet *ssh_new_packet(void) { struct Packet *pkt = snew(struct Packet); pkt->data = NULL; pkt->maxlen = 0; pkt->logmode = PKTLOG_EMIT; pkt->nblanks = 0; pkt->blanks = NULL; return pkt; } /* * Collect incoming data in the incoming packet buffer. * Decipher and verify the packet when it is completely read. * Drop SSH1_MSG_DEBUG and SSH1_MSG_IGNORE packets. * Update the *data and *datalen variables. * Return a Packet structure when a packet is completed. */ static struct Packet *ssh1_rdpkt(Ssh ssh, unsigned char **data, int *datalen) { struct rdpkt1_state_tag *st = &ssh->rdpkt1_state; crBegin(ssh->ssh1_rdpkt_crstate); st->pktin = ssh_new_packet(); st->pktin->type = 0; st->pktin->length = 0; for (st->i = st->len = 0; st->i < 4; st->i++) { while ((*datalen) == 0) crReturn(NULL); st->len = (st->len << 8) + **data; (*data)++, (*datalen)--; } st->pad = 8 - (st->len % 8); st->biglen = st->len + st->pad; st->pktin->length = st->len - 5; if (st->biglen < 0) { bombout(("Extremely large packet length from server suggests" " data stream corruption")); ssh_free_packet(st->pktin); crStop(NULL); } st->pktin->maxlen = st->biglen; st->pktin->data = snewn(st->biglen + APIEXTRA, unsigned char); st->to_read = st->biglen; st->p = st->pktin->data; while (st->to_read > 0) { st->chunk = st->to_read; while ((*datalen) == 0) crReturn(NULL); if (st->chunk > (*datalen)) st->chunk = (*datalen); memcpy(st->p, *data, st->chunk); *data += st->chunk; *datalen -= st->chunk; st->p += st->chunk; st->to_read -= st->chunk; } if (ssh->cipher && detect_attack(ssh->crcda_ctx, st->pktin->data, st->biglen, NULL)) { bombout(("Network attack (CRC compensation) detected!")); ssh_free_packet(st->pktin); crStop(NULL); } if (ssh->cipher) ssh->cipher->decrypt(ssh->v1_cipher_ctx, st->pktin->data, st->biglen); st->realcrc = crc32_compute(st->pktin->data, st->biglen - 4); st->gotcrc = GET_32BIT(st->pktin->data + st->biglen - 4); if (st->gotcrc != st->realcrc) { bombout(("Incorrect CRC received on packet")); ssh_free_packet(st->pktin); crStop(NULL); } st->pktin->body = st->pktin->data + st->pad + 1; st->pktin->savedpos = 0; if (ssh->v1_compressing) { unsigned char *decompblk; int decomplen; if (!zlib_decompress_block(ssh->sc_comp_ctx, st->pktin->body - 1, st->pktin->length + 1, &decompblk, &decomplen)) { bombout(("Zlib decompression encountered invalid data")); ssh_free_packet(st->pktin); crStop(NULL); } if (st->pktin->maxlen < st->pad + decomplen) { st->pktin->maxlen = st->pad + decomplen; st->pktin->data = sresize(st->pktin->data, st->pktin->maxlen + APIEXTRA, unsigned char); st->pktin->body = st->pktin->data + st->pad + 1; } memcpy(st->pktin->body - 1, decompblk, decomplen); sfree(decompblk); st->pktin->length = decomplen - 1; } st->pktin->type = st->pktin->body[-1]; /* * Log incoming packet, possibly omitting sensitive fields. */ if (ssh->logctx) { int nblanks = 0; struct logblank_t blank; if (ssh->cfg.logomitdata) { int do_blank = FALSE, blank_prefix = 0; /* "Session data" packets - omit the data field */ if ((st->pktin->type == SSH1_SMSG_STDOUT_DATA) || (st->pktin->type == SSH1_SMSG_STDERR_DATA)) { do_blank = TRUE; blank_prefix = 0; } else if (st->pktin->type == SSH1_MSG_CHANNEL_DATA) { do_blank = TRUE; blank_prefix = 4; } if (do_blank) { blank.offset = blank_prefix; blank.len = st->pktin->length; blank.type = PKTLOG_OMIT; nblanks = 1; } } log_packet(ssh->logctx, PKT_INCOMING, st->pktin->type, ssh1_pkt_type(st->pktin->type), st->pktin->body, st->pktin->length, nblanks, &blank); } crFinish(st->pktin); } static struct Packet *ssh2_rdpkt(Ssh ssh, unsigned char **data, int *datalen) { struct rdpkt2_state_tag *st = &ssh->rdpkt2_state; crBegin(ssh->ssh2_rdpkt_crstate); st->pktin = ssh_new_packet(); st->pktin->type = 0; st->pktin->length = 0; if (ssh->sccipher) st->cipherblk = ssh->sccipher->blksize; else st->cipherblk = 8; if (st->cipherblk < 8) st->cipherblk = 8; st->pktin->data = snewn(st->cipherblk + APIEXTRA, unsigned char); /* * Acquire and decrypt the first block of the packet. This will * contain the length and padding details. */ for (st->i = st->len = 0; st->i < st->cipherblk; st->i++) { while ((*datalen) == 0) crReturn(NULL); st->pktin->data[st->i] = *(*data)++; (*datalen)--; } if (ssh->sccipher) ssh->sccipher->decrypt(ssh->sc_cipher_ctx, st->pktin->data, st->cipherblk); /* * Now get the length and padding figures. */ st->len = GET_32BIT(st->pktin->data); st->pad = st->pktin->data[4]; /* * _Completely_ silly lengths should be stomped on before they * do us any more damage. */ if (st->len < 0 || st->pad < 0 || st->len + st->pad < 0) { bombout(("Incoming packet was garbled on decryption")); ssh_free_packet(st->pktin); crStop(NULL); } /* * This enables us to deduce the payload length. */ st->payload = st->len - st->pad - 1; st->pktin->length = st->payload + 5; /* * So now we can work out the total packet length. */ st->packetlen = st->len + 4; st->maclen = ssh->scmac ? ssh->scmac->len : 0; /* * Allocate memory for the rest of the packet. */ st->pktin->maxlen = st->packetlen + st->maclen; st->pktin->data = sresize(st->pktin->data, st->pktin->maxlen + APIEXTRA, unsigned char); /* * Read and decrypt the remainder of the packet. */ for (st->i = st->cipherblk; st->i < st->packetlen + st->maclen; st->i++) { while ((*datalen) == 0) crReturn(NULL); st->pktin->data[st->i] = *(*data)++; (*datalen)--; } /* Decrypt everything _except_ the MAC. */ if (ssh->sccipher) ssh->sccipher->decrypt(ssh->sc_cipher_ctx, st->pktin->data + st->cipherblk, st->packetlen - st->cipherblk); st->pktin->encrypted_len = st->packetlen; /* * Check the MAC. */ if (ssh->scmac && !ssh->scmac->verify(ssh->sc_mac_ctx, st->pktin->data, st->len + 4, st->incoming_sequence)) { bombout(("Incorrect MAC received on packet")); ssh_free_packet(st->pktin); crStop(NULL); } st->pktin->sequence = st->incoming_sequence++; /* * Decompress packet payload. */ { unsigned char *newpayload; int newlen; if (ssh->sccomp && ssh->sccomp->decompress(ssh->sc_comp_ctx, st->pktin->data + 5, st->pktin->length - 5, &newpayload, &newlen)) { if (st->pktin->maxlen < newlen + 5) { st->pktin->maxlen = newlen + 5; st->pktin->data = sresize(st->pktin->data, st->pktin->maxlen + APIEXTRA, unsigned char); } st->pktin->length = 5 + newlen; memcpy(st->pktin->data + 5, newpayload, newlen); sfree(newpayload); } } st->pktin->savedpos = 6; st->pktin->body = st->pktin->data; st->pktin->type = st->pktin->data[5]; /* * Log incoming packet, possibly omitting sensitive fields. */ if (ssh->logctx) { int nblanks = 0; struct logblank_t blank; if (ssh->cfg.logomitdata) { int do_blank = FALSE, blank_prefix = 0; /* "Session data" packets - omit the data field */ if (st->pktin->type == SSH2_MSG_CHANNEL_DATA) { do_blank = TRUE; blank_prefix = 4; } else if (st->pktin->type == SSH2_MSG_CHANNEL_EXTENDED_DATA) { do_blank = TRUE; blank_prefix = 8; } if (do_blank) { blank.offset = blank_prefix; blank.len = (st->pktin->length-6) - blank_prefix; blank.type = PKTLOG_OMIT; nblanks = 1; } } log_packet(ssh->logctx, PKT_INCOMING, st->pktin->type, ssh2_pkt_type(ssh->pkt_ctx, st->pktin->type), st->pktin->data+6, st->pktin->length-6, nblanks, &blank); } crFinish(st->pktin); } static void ssh1_pktout_size(struct Packet *pkt, int len) { int pad, biglen; len += 5; /* type and CRC */ pad = 8 - (len % 8); biglen = len + pad; pkt->length = len - 5; if (pkt->maxlen < biglen) { pkt->maxlen = biglen; pkt->data = sresize(pkt->data, biglen + 4 + APIEXTRA, unsigned char); } pkt->body = pkt->data + 4 + pad + 1; } static struct Packet *s_wrpkt_start(int type, int len) { struct Packet *pkt = ssh_new_packet(); ssh1_pktout_size(pkt, len); pkt->type = type; /* Initialise log omission state */ pkt->nblanks = 0; pkt->blanks = NULL; return pkt; } static int s_wrpkt_prepare(Ssh ssh, struct Packet *pkt) { int pad, biglen, i; unsigned long crc; #ifdef __SC__ /* * XXX various versions of SC (including 8.8.4) screw up the * register allocation in this function and use the same register * (D6) for len and as a temporary, with predictable results. The * following sledgehammer prevents this. */ volatile #endif int len; pkt->body[-1] = pkt->type; if (ssh->logctx) log_packet(ssh->logctx, PKT_OUTGOING, pkt->type, ssh1_pkt_type(pkt->type), pkt->body, pkt->length, pkt->nblanks, pkt->blanks); sfree(pkt->blanks); pkt->blanks = NULL; pkt->nblanks = 0; if (ssh->v1_compressing) { unsigned char *compblk; int complen; zlib_compress_block(ssh->cs_comp_ctx, pkt->body - 1, pkt->length + 1, &compblk, &complen); ssh1_pktout_size(pkt, complen - 1); memcpy(pkt->body - 1, compblk, complen); sfree(compblk); } len = pkt->length + 5; /* type and CRC */ pad = 8 - (len % 8); biglen = len + pad; for (i = 0; i < pad; i++) pkt->data[i + 4] = random_byte(); crc = crc32_compute(pkt->data + 4, biglen - 4); PUT_32BIT(pkt->data + biglen, crc); PUT_32BIT(pkt->data, len); if (ssh->cipher) ssh->cipher->encrypt(ssh->v1_cipher_ctx, pkt->data + 4, biglen); return biglen + 4; } static void s_wrpkt(Ssh ssh, struct Packet *pkt) { int len, backlog; len = s_wrpkt_prepare(ssh, pkt); backlog = sk_write(ssh->s, (char *)pkt->data, len); if (backlog > SSH_MAX_BACKLOG) ssh_throttle_all(ssh, 1, backlog); } static void s_wrpkt_defer(Ssh ssh, struct Packet *pkt) { int len; len = s_wrpkt_prepare(ssh, pkt); if (ssh->deferred_len + len > ssh->deferred_size) { ssh->deferred_size = ssh->deferred_len + len + 128; ssh->deferred_send_data = sresize(ssh->deferred_send_data, ssh->deferred_size, unsigned char); } memcpy(ssh->deferred_send_data + ssh->deferred_len, pkt->data, len); ssh->deferred_len += len; } /* * Construct a packet with the specified contents. */ static struct Packet *construct_packet(Ssh ssh, int pkttype, va_list ap1, va_list ap2) { unsigned char *p, *argp, argchar; unsigned long argint; int pktlen, argtype, arglen; Bignum bn; struct Packet *pkt; pktlen = 0; while ((argtype = va_arg(ap1, int)) != PKT_END) { switch (argtype) { case PKT_INT: (void) va_arg(ap1, int); pktlen += 4; break; case PKT_CHAR: (void) va_arg(ap1, int); pktlen++; break; case PKT_DATA: (void) va_arg(ap1, unsigned char *); arglen = va_arg(ap1, int); pktlen += arglen; break; case PKT_STR: argp = va_arg(ap1, unsigned char *); arglen = strlen((char *)argp); pktlen += 4 + arglen; break; case PKT_BIGNUM: bn = va_arg(ap1, Bignum); pktlen += ssh1_bignum_length(bn); break; case PKTT_PASSWORD: case PKTT_DATA: case PKTT_OTHER: /* ignore this pass */ break; default: assert(0); } } pkt = s_wrpkt_start(pkttype, pktlen); p = pkt->body; while ((argtype = va_arg(ap2, int)) != PKT_END) { int offset = p - pkt->body, len = 0; switch (argtype) { /* Actual fields in the packet */ case PKT_INT: argint = va_arg(ap2, int); PUT_32BIT(p, argint); len = 4; break; case PKT_CHAR: argchar = (unsigned char) va_arg(ap2, int); *p = argchar; len = 1; break; case PKT_DATA: argp = va_arg(ap2, unsigned char *); arglen = va_arg(ap2, int); memcpy(p, argp, arglen); len = arglen; break; case PKT_STR: argp = va_arg(ap2, unsigned char *); arglen = strlen((char *)argp); PUT_32BIT(p, arglen); memcpy(p + 4, argp, arglen); len = arglen + 4; break; case PKT_BIGNUM: bn = va_arg(ap2, Bignum); len = ssh1_write_bignum(p, bn); break; /* Tokens for modifications to packet logging */ case PKTT_PASSWORD: dont_log_password(ssh, pkt, PKTLOG_BLANK); break; case PKTT_DATA: dont_log_data(ssh, pkt, PKTLOG_OMIT); break; case PKTT_OTHER: end_log_omission(ssh, pkt); break; } p += len; /* Deal with logfile omission, if required. */ if (len && (pkt->logmode != PKTLOG_EMIT)) { pkt->nblanks++; pkt->blanks = sresize(pkt->blanks, pkt->nblanks, struct logblank_t); pkt->blanks[pkt->nblanks-1].offset = offset; pkt->blanks[pkt->nblanks-1].len = len; pkt->blanks[pkt->nblanks-1].type = pkt->logmode; } } return pkt; } static void send_packet(Ssh ssh, int pkttype, ...) { struct Packet *pkt; va_list ap1, ap2; va_start(ap1, pkttype); va_start(ap2, pkttype); pkt = construct_packet(ssh, pkttype, ap1, ap2); va_end(ap2); va_end(ap1); s_wrpkt(ssh, pkt); ssh_free_packet(pkt); } static void defer_packet(Ssh ssh, int pkttype, ...) { struct Packet *pkt; va_list ap1, ap2; va_start(ap1, pkttype); va_start(ap2, pkttype); pkt = construct_packet(ssh, pkttype, ap1, ap2); va_end(ap2); va_end(ap1); s_wrpkt_defer(ssh, pkt); ssh_free_packet(pkt); } static int ssh_versioncmp(char *a, char *b) { char *ae, *be; unsigned long av, bv; av = strtoul(a, &ae, 10); bv = strtoul(b, &be, 10); if (av != bv) return (av < bv ? -1 : +1); if (*ae == '.') ae++; if (*be == '.') be++; av = strtoul(ae, &ae, 10); bv = strtoul(be, &be, 10); if (av != bv) return (av < bv ? -1 : +1); return 0; } /* * Utility routines for putting an SSH-protocol `string' and * `uint32' into a SHA state. */ #include static void sha_string(SHA_State * s, void *str, int len) { unsigned char lenblk[4]; PUT_32BIT(lenblk, len); SHA_Bytes(s, lenblk, 4); SHA_Bytes(s, str, len); } static void sha_uint32(SHA_State * s, unsigned i) { unsigned char intblk[4]; PUT_32BIT(intblk, i); SHA_Bytes(s, intblk, 4); } /* * SSH-2 packet construction functions. */ static void ssh2_pkt_ensure(struct Packet *pkt, int length) { if (pkt->maxlen < length) { pkt->maxlen = length + 256; pkt->data = sresize(pkt->data, pkt->maxlen + APIEXTRA, unsigned char); } } static void ssh2_pkt_adddata(struct Packet *pkt, void *data, int len) { if (pkt->logmode != PKTLOG_EMIT) { pkt->nblanks++; pkt->blanks = sresize(pkt->blanks, pkt->nblanks, struct logblank_t); pkt->blanks[pkt->nblanks-1].offset = pkt->length - 6; pkt->blanks[pkt->nblanks-1].len = len; pkt->blanks[pkt->nblanks-1].type = pkt->logmode; } pkt->length += len; ssh2_pkt_ensure(pkt, pkt->length); memcpy(pkt->data + pkt->length - len, data, len); } static void ssh2_pkt_addbyte(struct Packet *pkt, unsigned char byte) { ssh2_pkt_adddata(pkt, &byte, 1); } static struct Packet *ssh2_pkt_init(int pkt_type) { struct Packet *pkt = ssh_new_packet(); pkt->length = 5; pkt->forcepad = 0; ssh2_pkt_addbyte(pkt, (unsigned char) pkt_type); return pkt; } static void ssh2_pkt_addbool(struct Packet *pkt, unsigned char value) { ssh2_pkt_adddata(pkt, &value, 1); } static void ssh2_pkt_adduint32(struct Packet *pkt, unsigned long value) { unsigned char x[4]; PUT_32BIT(x, value); ssh2_pkt_adddata(pkt, x, 4); } static void ssh2_pkt_addstring_start(struct Packet *pkt) { ssh2_pkt_adduint32(pkt, 0); pkt->savedpos = pkt->length; } static void ssh2_pkt_addstring_str(struct Packet *pkt, char *data) { ssh2_pkt_adddata(pkt, data, strlen(data)); PUT_32BIT(pkt->data + pkt->savedpos - 4, pkt->length - pkt->savedpos); } static void ssh2_pkt_addstring_data(struct Packet *pkt, char *data, int len) { ssh2_pkt_adddata(pkt, data, len); PUT_32BIT(pkt->data + pkt->savedpos - 4, pkt->length - pkt->savedpos); } static void ssh2_pkt_addstring(struct Packet *pkt, char *data) { ssh2_pkt_addstring_start(pkt); ssh2_pkt_addstring_str(pkt, data); } static unsigned char *ssh2_mpint_fmt(Bignum b, int *len) { unsigned char *p; int i, n = (bignum_bitcount(b) + 7) / 8; p = snewn(n + 1, unsigned char); if (!p) fatalbox("out of memory"); p[0] = 0; for (i = 1; i <= n; i++) p[i] = bignum_byte(b, n - i); i = 0; while (i <= n && p[i] == 0 && (p[i + 1] & 0x80) == 0) i++; memmove(p, p + i, n + 1 - i); *len = n + 1 - i; return p; } static void ssh2_pkt_addmp(struct Packet *pkt, Bignum b) { unsigned char *p; int len; p = ssh2_mpint_fmt(b, &len); ssh2_pkt_addstring_start(pkt); ssh2_pkt_addstring_data(pkt, (char *)p, len); sfree(p); } /* * Construct an SSH-2 final-form packet: compress it, encrypt it, * put the MAC on it. Final packet, ready to be sent, is stored in * pkt->data. Total length is returned. */ static int ssh2_pkt_construct(Ssh ssh, struct Packet *pkt) { int cipherblk, maclen, padding, i; if (ssh->logctx) log_packet(ssh->logctx, PKT_OUTGOING, pkt->data[5], ssh2_pkt_type(ssh->pkt_ctx, pkt->data[5]), pkt->data + 6, pkt->length - 6, pkt->nblanks, pkt->blanks); sfree(pkt->blanks); pkt->blanks = NULL; pkt->nblanks = 0; /* * Compress packet payload. */ { unsigned char *newpayload; int newlen; if (ssh->cscomp && ssh->cscomp->compress(ssh->cs_comp_ctx, pkt->data + 5, pkt->length - 5, &newpayload, &newlen)) { pkt->length = 5; ssh2_pkt_adddata(pkt, newpayload, newlen); sfree(newpayload); } } /* * Add padding. At least four bytes, and must also bring total * length (minus MAC) up to a multiple of the block size. * If pkt->forcepad is set, make sure the packet is at least that size * after padding. */ cipherblk = ssh->cscipher ? ssh->cscipher->blksize : 8; /* block size */ cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */ padding = 4; if (pkt->length + padding < pkt->forcepad) padding = pkt->forcepad - pkt->length; padding += (cipherblk - (pkt->length + padding) % cipherblk) % cipherblk; assert(padding <= 255); maclen = ssh->csmac ? ssh->csmac->len : 0; ssh2_pkt_ensure(pkt, pkt->length + padding + maclen); pkt->data[4] = padding; for (i = 0; i < padding; i++) pkt->data[pkt->length + i] = random_byte(); PUT_32BIT(pkt->data, pkt->length + padding - 4); if (ssh->csmac) ssh->csmac->generate(ssh->cs_mac_ctx, pkt->data, pkt->length + padding, ssh->v2_outgoing_sequence); ssh->v2_outgoing_sequence++; /* whether or not we MACed */ if (ssh->cscipher) ssh->cscipher->encrypt(ssh->cs_cipher_ctx, pkt->data, pkt->length + padding); pkt->encrypted_len = pkt->length + padding; /* Ready-to-send packet starts at pkt->data. We return length. */ return pkt->length + padding + maclen; } /* * Routines called from the main SSH code to send packets. There * are quite a few of these, because we have two separate * mechanisms for delaying the sending of packets: * * - In order to send an IGNORE message and a password message in * a single fixed-length blob, we require the ability to * concatenate the encrypted forms of those two packets _into_ a * single blob and then pass it to our transport * layer in one go. Hence, there's a deferment mechanism which * works after packet encryption. * * - In order to avoid sending any connection-layer messages * during repeat key exchange, we have to queue up any such * outgoing messages _before_ they are encrypted (and in * particular before they're allocated sequence numbers), and * then send them once we've finished. * * I call these mechanisms `defer' and `queue' respectively, so as * to distinguish them reasonably easily. * * The functions send_noqueue() and defer_noqueue() free the packet * structure they are passed. Every outgoing packet goes through * precisely one of these functions in its life; packets passed to * ssh2_pkt_send() or ssh2_pkt_defer() either go straight to one of * these or get queued, and then when the queue is later emptied * the packets are all passed to defer_noqueue(). */ /* * Send an SSH-2 packet immediately, without queuing or deferring. */ static void ssh2_pkt_send_noqueue(Ssh ssh, struct Packet *pkt) { int len; int backlog; len = ssh2_pkt_construct(ssh, pkt); backlog = sk_write(ssh->s, (char *)pkt->data, len); if (backlog > SSH_MAX_BACKLOG) ssh_throttle_all(ssh, 1, backlog); ssh->outgoing_data_size += pkt->encrypted_len; if (!ssh->kex_in_progress && ssh->max_data_size != 0 && ssh->outgoing_data_size > ssh->max_data_size) do_ssh2_transport(ssh, "too much data sent", -1, NULL); ssh_free_packet(pkt); } /* * Defer an SSH-2 packet. */ static void ssh2_pkt_defer_noqueue(Ssh ssh, struct Packet *pkt) { int len = ssh2_pkt_construct(ssh, pkt); if (ssh->deferred_len + len > ssh->deferred_size) { ssh->deferred_size = ssh->deferred_len + len + 128; ssh->deferred_send_data = sresize(ssh->deferred_send_data, ssh->deferred_size, unsigned char); } memcpy(ssh->deferred_send_data + ssh->deferred_len, pkt->data, len); ssh->deferred_len += len; ssh->deferred_data_size += pkt->encrypted_len; ssh_free_packet(pkt); } /* * Queue an SSH-2 packet. */ static void ssh2_pkt_queue(Ssh ssh, struct Packet *pkt) { assert(ssh->queueing); if (ssh->queuelen >= ssh->queuesize) { ssh->queuesize = ssh->queuelen + 32; ssh->queue = sresize(ssh->queue, ssh->queuesize, struct Packet *); } ssh->queue[ssh->queuelen++] = pkt; } /* * Either queue or send a packet, depending on whether queueing is * set. */ static void ssh2_pkt_send(Ssh ssh, struct Packet *pkt) { if (ssh->queueing) ssh2_pkt_queue(ssh, pkt); else ssh2_pkt_send_noqueue(ssh, pkt); } #if 0 /* disused */ /* * Either queue or defer a packet, depending on whether queueing is * set. */ static void ssh2_pkt_defer(Ssh ssh, struct Packet *pkt) { if (ssh->queueing) ssh2_pkt_queue(ssh, pkt); else ssh2_pkt_defer_noqueue(ssh, pkt); } #endif /* * Send the whole deferred data block constructed by * ssh2_pkt_defer() or SSH-1's defer_packet(). * * The expected use of the defer mechanism is that you call * ssh2_pkt_defer() a few times, then call ssh_pkt_defersend(). If * not currently queueing, this simply sets up deferred_send_data * and then sends it. If we _are_ currently queueing, the calls to * ssh2_pkt_defer() put the deferred packets on to the queue * instead, and therefore ssh_pkt_defersend() has no deferred data * to send. Hence, there's no need to make it conditional on * ssh->queueing. */ static void ssh_pkt_defersend(Ssh ssh) { int backlog; backlog = sk_write(ssh->s, (char *)ssh->deferred_send_data, ssh->deferred_len); ssh->deferred_len = ssh->deferred_size = 0; sfree(ssh->deferred_send_data); ssh->deferred_send_data = NULL; if (backlog > SSH_MAX_BACKLOG) ssh_throttle_all(ssh, 1, backlog); ssh->outgoing_data_size += ssh->deferred_data_size; if (!ssh->kex_in_progress && ssh->max_data_size != 0 && ssh->outgoing_data_size > ssh->max_data_size) do_ssh2_transport(ssh, "too much data sent", -1, NULL); ssh->deferred_data_size = 0; } /* * Send all queued SSH-2 packets. We send them by means of * ssh2_pkt_defer_noqueue(), in case they included a pair of * packets that needed to be lumped together. */ static void ssh2_pkt_queuesend(Ssh ssh) { int i; assert(!ssh->queueing); for (i = 0; i < ssh->queuelen; i++) ssh2_pkt_defer_noqueue(ssh, ssh->queue[i]); ssh->queuelen = 0; ssh_pkt_defersend(ssh); } #if 0 void bndebug(char *string, Bignum b) { unsigned char *p; int i, len; p = ssh2_mpint_fmt(b, &len); debug(("%s", string)); for (i = 0; i < len; i++) debug((" %02x", p[i])); debug(("\n")); sfree(p); } #endif static void sha_mpint(SHA_State * s, Bignum b) { unsigned char *p; int len; p = ssh2_mpint_fmt(b, &len); sha_string(s, p, len); sfree(p); } /* * Packet decode functions for both SSH-1 and SSH-2. */ static unsigned long ssh_pkt_getuint32(struct Packet *pkt) { unsigned long value; if (pkt->length - pkt->savedpos < 4) return 0; /* arrgh, no way to decline (FIXME?) */ value = GET_32BIT(pkt->body + pkt->savedpos); pkt->savedpos += 4; return value; } static int ssh2_pkt_getbool(struct Packet *pkt) { unsigned long value; if (pkt->length - pkt->savedpos < 1) return 0; /* arrgh, no way to decline (FIXME?) */ value = pkt->body[pkt->savedpos] != 0; pkt->savedpos++; return value; } static void ssh_pkt_getstring(struct Packet *pkt, char **p, int *length) { int len; *p = NULL; *length = 0; if (pkt->length - pkt->savedpos < 4) return; len = GET_32BIT(pkt->body + pkt->savedpos); if (len < 0) return; *length = len; pkt->savedpos += 4; if (pkt->length - pkt->savedpos < *length) return; *p = (char *)(pkt->body + pkt->savedpos); pkt->savedpos += *length; } static void *ssh_pkt_getdata(struct Packet *pkt, int length) { if (pkt->length - pkt->savedpos < length) return NULL; pkt->savedpos += length; return pkt->body + (pkt->savedpos - length); } static int ssh1_pkt_getrsakey(struct Packet *pkt, struct RSAKey *key, unsigned char **keystr) { int j; j = makekey(pkt->body + pkt->savedpos, pkt->length - pkt->savedpos, key, keystr, 0); if (j < 0) return FALSE; pkt->savedpos += j; assert(pkt->savedpos < pkt->length); return TRUE; } static Bignum ssh1_pkt_getmp(struct Packet *pkt) { int j; Bignum b; j = ssh1_read_bignum(pkt->body + pkt->savedpos, pkt->length - pkt->savedpos, &b); if (j < 0) return NULL; pkt->savedpos += j; return b; } static Bignum ssh2_pkt_getmp(struct Packet *pkt) { char *p; int length; Bignum b; ssh_pkt_getstring(pkt, &p, &length); if (!p) return NULL; if (p[0] & 0x80) return NULL; b = bignum_from_bytes((unsigned char *)p, length); return b; } /* * Helper function to add an SSH-2 signature blob to a packet. * Expects to be shown the public key blob as well as the signature * blob. Normally works just like ssh2_pkt_addstring, but will * fiddle with the signature packet if necessary for * BUG_SSH2_RSA_PADDING. */ static void ssh2_add_sigblob(Ssh ssh, struct Packet *pkt, void *pkblob_v, int pkblob_len, void *sigblob_v, int sigblob_len) { unsigned char *pkblob = (unsigned char *)pkblob_v; unsigned char *sigblob = (unsigned char *)sigblob_v; /* dmemdump(pkblob, pkblob_len); */ /* dmemdump(sigblob, sigblob_len); */ /* * See if this is in fact an ssh-rsa signature and a buggy * server; otherwise we can just do this the easy way. */ if ((ssh->remote_bugs & BUG_SSH2_RSA_PADDING) && (GET_32BIT(pkblob) == 7 && !memcmp(pkblob+4, "ssh-rsa", 7))) { int pos, len, siglen; /* * Find the byte length of the modulus. */ pos = 4+7; /* skip over "ssh-rsa" */ pos += 4 + GET_32BIT(pkblob+pos); /* skip over exponent */ len = GET_32BIT(pkblob+pos); /* find length of modulus */ pos += 4; /* find modulus itself */ while (len > 0 && pkblob[pos] == 0) len--, pos++; /* debug(("modulus length is %d\n", len)); */ /* * Now find the signature integer. */ pos = 4+7; /* skip over "ssh-rsa" */ siglen = GET_32BIT(sigblob+pos); /* debug(("signature length is %d\n", siglen)); */ if (len != siglen) { unsigned char newlen[4]; ssh2_pkt_addstring_start(pkt); ssh2_pkt_addstring_data(pkt, (char *)sigblob, pos); /* dmemdump(sigblob, pos); */ pos += 4; /* point to start of actual sig */ PUT_32BIT(newlen, len); ssh2_pkt_addstring_data(pkt, (char *)newlen, 4); /* dmemdump(newlen, 4); */ newlen[0] = 0; while (len-- > siglen) { ssh2_pkt_addstring_data(pkt, (char *)newlen, 1); /* dmemdump(newlen, 1); */ } ssh2_pkt_addstring_data(pkt, (char *)(sigblob+pos), siglen); /* dmemdump(sigblob+pos, siglen); */ return; } /* Otherwise fall through and do it the easy way. */ } ssh2_pkt_addstring_start(pkt); ssh2_pkt_addstring_data(pkt, (char *)sigblob, sigblob_len); } /* * Examine the remote side's version string and compare it against * a list of known buggy implementations. */ static void ssh_detect_bugs(Ssh ssh, char *vstring) { char *imp; /* pointer to implementation part */ imp = vstring; imp += strcspn(imp, "-"); if (*imp) imp++; imp += strcspn(imp, "-"); if (*imp) imp++; ssh->remote_bugs = 0; if (ssh->cfg.sshbug_ignore1 == FORCE_ON || (ssh->cfg.sshbug_ignore1 == AUTO && (!strcmp(imp, "1.2.18") || !strcmp(imp, "1.2.19") || !strcmp(imp, "1.2.20") || !strcmp(imp, "1.2.21") || !strcmp(imp, "1.2.22") || !strcmp(imp, "Cisco-1.25") || !strcmp(imp, "OSU_1.4alpha3") || !strcmp(imp, "OSU_1.5alpha4")))) { /* * These versions don't support SSH1_MSG_IGNORE, so we have * to use a different defence against password length * sniffing. */ ssh->remote_bugs |= BUG_CHOKES_ON_SSH1_IGNORE; logevent("We believe remote version has SSH-1 ignore bug"); } if (ssh->cfg.sshbug_plainpw1 == FORCE_ON || (ssh->cfg.sshbug_plainpw1 == AUTO && (!strcmp(imp, "Cisco-1.25") || !strcmp(imp, "OSU_1.4alpha3")))) { /* * These versions need a plain password sent; they can't * handle having a null and a random length of data after * the password. */ ssh->remote_bugs |= BUG_NEEDS_SSH1_PLAIN_PASSWORD; logevent("We believe remote version needs a plain SSH-1 password"); } if (ssh->cfg.sshbug_rsa1 == FORCE_ON || (ssh->cfg.sshbug_rsa1 == AUTO && (!strcmp(imp, "Cisco-1.25")))) { /* * These versions apparently have no clue whatever about * RSA authentication and will panic and die if they see * an AUTH_RSA message. */ ssh->remote_bugs |= BUG_CHOKES_ON_RSA; logevent("We believe remote version can't handle SSH-1 RSA authentication"); } if (ssh->cfg.sshbug_hmac2 == FORCE_ON || (ssh->cfg.sshbug_hmac2 == AUTO && !wc_match("* VShell", imp) && (wc_match("2.1.0*", imp) || wc_match("2.0.*", imp) || wc_match("2.2.0*", imp) || wc_match("2.3.0*", imp) || wc_match("2.1 *", imp)))) { /* * These versions have the HMAC bug. */ ssh->remote_bugs |= BUG_SSH2_HMAC; logevent("We believe remote version has SSH-2 HMAC bug"); } if (ssh->cfg.sshbug_derivekey2 == FORCE_ON || (ssh->cfg.sshbug_derivekey2 == AUTO && !wc_match("* VShell", imp) && (wc_match("2.0.0*", imp) || wc_match("2.0.10*", imp) ))) { /* * These versions have the key-derivation bug (failing to * include the literal shared secret in the hashes that * generate the keys). */ ssh->remote_bugs |= BUG_SSH2_DERIVEKEY; logevent("We believe remote version has SSH-2 key-derivation bug"); } if (ssh->cfg.sshbug_rsapad2 == FORCE_ON || (ssh->cfg.sshbug_rsapad2 == AUTO && (wc_match("OpenSSH_2.[5-9]*", imp) || wc_match("OpenSSH_3.[0-2]*", imp)))) { /* * These versions have the SSH-2 RSA padding bug. */ ssh->remote_bugs |= BUG_SSH2_RSA_PADDING; logevent("We believe remote version has SSH-2 RSA padding bug"); } if (ssh->cfg.sshbug_pksessid2 == FORCE_ON || (ssh->cfg.sshbug_pksessid2 == AUTO && wc_match("OpenSSH_2.[0-2]*", imp))) { /* * These versions have the SSH-2 session-ID bug in * public-key authentication. */ ssh->remote_bugs |= BUG_SSH2_PK_SESSIONID; logevent("We believe remote version has SSH-2 public-key-session-ID bug"); } if (ssh->cfg.sshbug_rekey2 == FORCE_ON || (ssh->cfg.sshbug_rekey2 == AUTO && (wc_match("OpenSSH_2.[0-4]*", imp) || wc_match("OpenSSH_2.5.[0-3]*", imp) || wc_match("Sun_SSH_1.0", imp) || wc_match("Sun_SSH_1.0.1", imp)))) { /* * These versions have the SSH-2 rekey bug. */ ssh->remote_bugs |= BUG_SSH2_REKEY; logevent("We believe remote version has SSH-2 rekey bug"); } } /* * The `software version' part of an SSH version string is required * to contain no spaces or minus signs. */ static void ssh_fix_verstring(char *str) { /* Eat "SSH--". */ assert(*str == 'S'); str++; assert(*str == 'S'); str++; assert(*str == 'H'); str++; assert(*str == '-'); str++; while (*str && *str != '-') str++; assert(*str == '-'); str++; /* Convert minus signs and spaces in the remaining string into * underscores. */ while (*str) { if (*str == '-' || *str == ' ') *str = '_'; str++; } } static int do_ssh_init(Ssh ssh, unsigned char c) { struct do_ssh_init_state { int vslen; char version[10]; char *vstring; int vstrsize; int i; int proto1, proto2; }; crState(do_ssh_init_state); crBegin(ssh->do_ssh_init_crstate); /* Search for the string "SSH-" in the input. */ s->i = 0; while (1) { static const int transS[] = { 1, 2, 2, 1 }; static const int transH[] = { 0, 0, 3, 0 }; static const int transminus[] = { 0, 0, 0, -1 }; if (c == 'S') s->i = transS[s->i]; else if (c == 'H') s->i = transH[s->i]; else if (c == '-') s->i = transminus[s->i]; else s->i = 0; if (s->i < 0) break; crReturn(1); /* get another character */ } s->vstrsize = 16; s->vstring = snewn(s->vstrsize, char); strcpy(s->vstring, "SSH-"); s->vslen = 4; s->i = 0; while (1) { crReturn(1); /* get another char */ if (s->vslen >= s->vstrsize - 1) { s->vstrsize += 16; s->vstring = sresize(s->vstring, s->vstrsize, char); } s->vstring[s->vslen++] = c; if (s->i >= 0) { if (c == '-') { s->version[s->i] = '\0'; s->i = -1; } else if (s->i < sizeof(s->version) - 1) s->version[s->i++] = c; } else if (c == '\012') break; } ssh->agentfwd_enabled = FALSE; ssh->rdpkt2_state.incoming_sequence = 0; s->vstring[s->vslen] = 0; s->vstring[strcspn(s->vstring, "\015\012")] = '\0';/* remove EOL chars */ logeventf(ssh, "Server version: %s", s->vstring); ssh_detect_bugs(ssh, s->vstring); /* * Decide which SSH protocol version to support. */ /* Anything strictly below "2.0" means protocol 1 is supported. */ s->proto1 = ssh_versioncmp(s->version, "2.0") < 0; /* Anything greater or equal to "1.99" means protocol 2 is supported. */ s->proto2 = ssh_versioncmp(s->version, "1.99") >= 0; if (ssh->cfg.sshprot == 0 && !s->proto1) { bombout(("SSH protocol version 1 required by user but not provided by server")); crStop(0); } if (ssh->cfg.sshprot == 3 && !s->proto2) { bombout(("SSH protocol version 2 required by user but not provided by server")); crStop(0); } { char *verstring; if (s->proto2 && (ssh->cfg.sshprot >= 2 || !s->proto1)) { /* * Construct a v2 version string. */ verstring = dupprintf("SSH-2.0-%s\015\012", sshver); ssh->version = 2; } else { /* * Construct a v1 version string. */ verstring = dupprintf("SSH-%s-%s\012", (ssh_versioncmp(s->version, "1.5") <= 0 ? s->version : "1.5"), sshver); ssh->version = 1; } ssh_fix_verstring(verstring); if (ssh->version == 2) { /* * Hash our version string and their version string. */ SHA_Init(&ssh->exhashbase); sha_string(&ssh->exhashbase, verstring, strcspn(verstring, "\015\012")); sha_string(&ssh->exhashbase, s->vstring, strcspn(s->vstring, "\015\012")); /* * Initialise SSH-2 protocol. */ ssh->protocol = ssh2_protocol; ssh2_protocol_setup(ssh); ssh->s_rdpkt = ssh2_rdpkt; } else { /* * Initialise SSH-1 protocol. */ ssh->protocol = ssh1_protocol; ssh1_protocol_setup(ssh); ssh->s_rdpkt = ssh1_rdpkt; } logeventf(ssh, "We claim version: %.*s", strcspn(verstring, "\015\012"), verstring); sk_write(ssh->s, verstring, strlen(verstring)); sfree(verstring); } logeventf(ssh, "Using SSH protocol version %d", ssh->version); update_specials_menu(ssh->frontend); ssh->state = SSH_STATE_BEFORE_SIZE; ssh->pinger = pinger_new(&ssh->cfg, &ssh_backend, ssh); sfree(s->vstring); crFinish(0); } static void ssh_process_incoming_data(Ssh ssh, unsigned char **data, int *datalen) { struct Packet *pktin = ssh->s_rdpkt(ssh, data, datalen); if (pktin) { ssh->protocol(ssh, NULL, 0, pktin); ssh_free_packet(pktin); } } static void ssh_queue_incoming_data(Ssh ssh, unsigned char **data, int *datalen) { bufchain_add(&ssh->queued_incoming_data, *data, *datalen); *data += *datalen; *datalen = 0; } static void ssh_process_queued_incoming_data(Ssh ssh) { void *vdata; unsigned char *data; int len, origlen; while (!ssh->frozen && bufchain_size(&ssh->queued_incoming_data)) { bufchain_prefix(&ssh->queued_incoming_data, &vdata, &len); data = vdata; origlen = len; while (!ssh->frozen && len > 0) ssh_process_incoming_data(ssh, &data, &len); if (origlen > len) bufchain_consume(&ssh->queued_incoming_data, origlen - len); } } static void ssh_set_frozen(Ssh ssh, int frozen) { if (ssh->s) sk_set_frozen(ssh->s, frozen); ssh->frozen = frozen; } static void ssh_gotdata(Ssh ssh, unsigned char *data, int datalen) { crBegin(ssh->ssh_gotdata_crstate); /* * To begin with, feed the characters one by one to the * protocol initialisation / selection function do_ssh_init(). * When that returns 0, we're done with the initial greeting * exchange and can move on to packet discipline. */ while (1) { int ret; /* need not be kept across crReturn */ if (datalen == 0) crReturnV; /* more data please */ ret = do_ssh_init(ssh, *data); data++; datalen--; if (ret == 0) break; } /* * We emerge from that loop when the initial negotiation is * over and we have selected an s_rdpkt function. Now pass * everything to s_rdpkt, and then pass the resulting packets * to the proper protocol handler. */ if (datalen == 0) crReturnV; /* * Process queued data if there is any. */ ssh_process_queued_incoming_data(ssh); while (1) { while (datalen > 0) { if (ssh->frozen) ssh_queue_incoming_data(ssh, &data, &datalen); ssh_process_incoming_data(ssh, &data, &datalen); if (ssh->state == SSH_STATE_CLOSED) return; } crReturnV; } crFinishV; } static int ssh_do_close(Ssh ssh, int notify_exit) { int ret = 0; struct ssh_channel *c; ssh->state = SSH_STATE_CLOSED; expire_timer_context(ssh); if (ssh->s) { sk_close(ssh->s); ssh->s = NULL; if (notify_exit) notify_remote_exit(ssh->frontend); else ret = 1; } /* * Now we must shut down any port- and X-forwarded channels going * through this connection. */ if (ssh->channels) { while (NULL != (c = index234(ssh->channels, 0))) { switch (c->type) { case CHAN_X11: x11_close(c->u.x11.s); break; case CHAN_SOCKDATA: pfd_close(c->u.pfd.s); break; } del234(ssh->channels, c); /* moving next one to index 0 */ if (ssh->version == 2) bufchain_clear(&c->v.v2.outbuffer); sfree(c); } } /* * Go through port-forwardings, and close any associated * listening sockets. */ if (ssh->portfwds) { struct ssh_portfwd *pf; while (NULL != (pf = index234(ssh->portfwds, 0))) { /* Dispose of any listening socket. */ if (pf->local) pfd_terminate(pf->local); del234(ssh->portfwds, pf); /* moving next one to index 0 */ free_portfwd(pf); } } return ret; } static void ssh_log(Plug plug, int type, SockAddr addr, int port, const char *error_msg, int error_code) { Ssh ssh = (Ssh) plug; char addrbuf[256], *msg; sk_getaddr(addr, addrbuf, lenof(addrbuf)); if (type == 0) msg = dupprintf("Connecting to %s port %d", addrbuf, port); else msg = dupprintf("Failed to connect to %s: %s", addrbuf, error_msg); logevent(msg); sfree(msg); } static int ssh_closing(Plug plug, const char *error_msg, int error_code, int calling_back) { Ssh ssh = (Ssh) plug; int need_notify = ssh_do_close(ssh, FALSE); if (!error_msg && !ssh->close_expected) { error_msg = "Server unexpectedly closed network connection"; } if (need_notify) notify_remote_exit(ssh->frontend); if (error_msg) { /* A socket error has occurred. */ logevent(error_msg); connection_fatal(ssh->frontend, "%s", error_msg); } else { logevent("Server closed network connection"); } return 0; } static int ssh_receive(Plug plug, int urgent, char *data, int len) { Ssh ssh = (Ssh) plug; ssh_gotdata(ssh, (unsigned char *)data, len); if (ssh->state == SSH_STATE_CLOSED) { ssh_do_close(ssh, TRUE); return 0; } return 1; } static void ssh_sent(Plug plug, int bufsize) { Ssh ssh = (Ssh) plug; /* * If the send backlog on the SSH socket itself clears, we * should unthrottle the whole world if it was throttled. */ if (bufsize < SSH_MAX_BACKLOG) ssh_throttle_all(ssh, 0, bufsize); } /* * Connect to specified host and port. * Returns an error message, or NULL on success. * Also places the canonical host name into `realhost'. It must be * freed by the caller. */ static const char *connect_to_host(Ssh ssh, char *host, int port, char **realhost, int nodelay, int keepalive) { static const struct plug_function_table fn_table = { ssh_log, ssh_closing, ssh_receive, ssh_sent, NULL }; SockAddr addr; const char *err; ssh->savedhost = snewn(1 + strlen(host), char); if (!ssh->savedhost) fatalbox("Out of memory"); strcpy(ssh->savedhost, host); if (port < 0) port = 22; /* default ssh port */ ssh->savedport = port; /* * Try to find host. */ logeventf(ssh, "Looking up host \"%s\"%s", host, (ssh->cfg.addressfamily == ADDRTYPE_IPV4 ? " (IPv4)" : (ssh->cfg.addressfamily == ADDRTYPE_IPV6 ? " (IPv6)" : ""))); addr = name_lookup(host, port, realhost, &ssh->cfg, ssh->cfg.addressfamily); if ((err = sk_addr_error(addr)) != NULL) { sk_addr_free(addr); return err; } /* * Open socket. */ ssh->fn = &fn_table; ssh->s = new_connection(addr, *realhost, port, 0, 1, nodelay, keepalive, (Plug) ssh, &ssh->cfg); if ((err = sk_socket_error(ssh->s)) != NULL) { ssh->s = NULL; notify_remote_exit(ssh->frontend); return err; } return NULL; } /* * Throttle or unthrottle the SSH connection. */ static void ssh1_throttle(Ssh ssh, int adjust) { int old_count = ssh->v1_throttle_count; ssh->v1_throttle_count += adjust; assert(ssh->v1_throttle_count >= 0); if (ssh->v1_throttle_count && !old_count) { ssh_set_frozen(ssh, 1); } else if (!ssh->v1_throttle_count && old_count) { ssh_set_frozen(ssh, 0); } } /* * Throttle or unthrottle _all_ local data streams (for when sends * on the SSH connection itself back up). */ static void ssh_throttle_all(Ssh ssh, int enable, int bufsize) { int i; struct ssh_channel *c; if (enable == ssh->throttled_all) return; ssh->throttled_all = enable; ssh->overall_bufsize = bufsize; if (!ssh->channels) return; for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) { switch (c->type) { case CHAN_MAINSESSION: /* * This is treated separately, outside the switch. */ break; case CHAN_X11: x11_override_throttle(c->u.x11.s, enable); break; case CHAN_AGENT: /* Agent channels require no buffer management. */ break; case CHAN_SOCKDATA: pfd_override_throttle(c->u.pfd.s, enable); break; } } } /* * Username and password input, abstracted off into routines * reusable in several places - even between SSH-1 and SSH-2. */ /* Set up a username or password input loop on a given buffer. */ static void setup_userpass_input(Ssh ssh, char *buffer, int buflen, int echo) { ssh->userpass_input_buffer = buffer; ssh->userpass_input_buflen = buflen; ssh->userpass_input_bufpos = 0; ssh->userpass_input_echo = echo; } /* * Process some terminal data in the course of username/password * input. Returns >0 for success (line of input returned in * buffer), <0 for failure (user hit ^C/^D, bomb out and exit), 0 * for inconclusive (keep waiting for more input please). */ static int process_userpass_input(Ssh ssh, unsigned char *in, int inlen) { char c; while (inlen--) { switch (c = *in++) { case 10: case 13: ssh->userpass_input_buffer[ssh->userpass_input_bufpos] = 0; ssh->userpass_input_buffer[ssh->userpass_input_buflen-1] = 0; return +1; break; case 8: case 127: if (ssh->userpass_input_bufpos > 0) { if (ssh->userpass_input_echo) c_write_str(ssh, "\b \b"); ssh->userpass_input_bufpos--; } break; case 21: case 27: while (ssh->userpass_input_bufpos > 0) { if (ssh->userpass_input_echo) c_write_str(ssh, "\b \b"); ssh->userpass_input_bufpos--; } break; case 3: case 4: return -1; break; default: /* * This simplistic check for printability is disabled * when we're doing password input, because some people * have control characters in their passwords.o */ if ((!ssh->userpass_input_echo || (c >= ' ' && c <= '~') || ((unsigned char) c >= 160)) && ssh->userpass_input_bufpos < ssh->userpass_input_buflen-1) { ssh->userpass_input_buffer[ssh->userpass_input_bufpos++] = c; if (ssh->userpass_input_echo) c_write(ssh, &c, 1); } break; } } return 0; } static void ssh_agent_callback(void *sshv, void *reply, int replylen) { Ssh ssh = (Ssh) sshv; ssh->agent_response = reply; ssh->agent_response_len = replylen; if (ssh->version == 1) do_ssh1_login(ssh, NULL, -1, NULL); else do_ssh2_authconn(ssh, NULL, -1, NULL); } static void ssh_dialog_callback(void *sshv, int ret) { Ssh ssh = (Ssh) sshv; ssh->user_response = ret; if (ssh->version == 1) do_ssh1_login(ssh, NULL, -1, NULL); else do_ssh2_transport(ssh, NULL, -1, NULL); /* * This may have unfrozen the SSH connection, so do a * queued-data run. */ ssh_process_queued_incoming_data(ssh); } static void ssh_agentf_callback(void *cv, void *reply, int replylen) { struct ssh_channel *c = (struct ssh_channel *)cv; Ssh ssh = c->ssh; void *sentreply = reply; if (!sentreply) { /* Fake SSH_AGENT_FAILURE. */ sentreply = "\0\0\0\1\5"; replylen = 5; } if (ssh->version == 2) { ssh2_add_channel_data(c, sentreply, replylen); ssh2_try_send(c); } else { send_packet(ssh, SSH1_MSG_CHANNEL_DATA, PKT_INT, c->remoteid, PKTT_DATA, PKT_INT, replylen, PKT_DATA, sentreply, replylen, PKTT_OTHER, PKT_END); } if (reply) sfree(reply); } /* * Handle the key exchange and user authentication phases. */ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, struct Packet *pktin) { int i, j, ret; unsigned char cookie[8], *ptr; struct RSAKey servkey, hostkey; struct MD5Context md5c; struct do_ssh1_login_state { int len; unsigned char *rsabuf, *keystr1, *keystr2; unsigned long supported_ciphers_mask, supported_auths_mask; int tried_publickey, tried_agent; int tis_auth_refused, ccard_auth_refused; unsigned char session_id[16]; int cipher_type; char username[100]; void *publickey_blob; int publickey_bloblen; char password[100]; char prompt[200]; int pos; char c; int pwpkt_type; unsigned char request[5], *response, *p; int responselen; int keyi, nkeys; int authed; struct RSAKey key; Bignum challenge; char *commentp; int commentlen; int dlgret; }; crState(do_ssh1_login_state); crBegin(ssh->do_ssh1_login_crstate); if (!pktin) crWaitUntil(pktin); if (pktin->type != SSH1_SMSG_PUBLIC_KEY) { bombout(("Public key packet not received")); crStop(0); } logevent("Received public keys"); ptr = ssh_pkt_getdata(pktin, 8); if (!ptr) { bombout(("SSH-1 public key packet stopped before random cookie")); crStop(0); } memcpy(cookie, ptr, 8); if (!ssh1_pkt_getrsakey(pktin, &servkey, &s->keystr1) || !ssh1_pkt_getrsakey(pktin, &hostkey, &s->keystr2)) { bombout(("Failed to read SSH-1 public keys from public key packet")); crStop(0); } /* * Log the host key fingerprint. */ { char logmsg[80]; logevent("Host key fingerprint is:"); strcpy(logmsg, " "); hostkey.comment = NULL; rsa_fingerprint(logmsg + strlen(logmsg), sizeof(logmsg) - strlen(logmsg), &hostkey); logevent(logmsg); } ssh->v1_remote_protoflags = ssh_pkt_getuint32(pktin); s->supported_ciphers_mask = ssh_pkt_getuint32(pktin); s->supported_auths_mask = ssh_pkt_getuint32(pktin); ssh->v1_local_protoflags = ssh->v1_remote_protoflags & SSH1_PROTOFLAGS_SUPPORTED; ssh->v1_local_protoflags |= SSH1_PROTOFLAG_SCREEN_NUMBER; MD5Init(&md5c); MD5Update(&md5c, s->keystr2, hostkey.bytes); MD5Update(&md5c, s->keystr1, servkey.bytes); MD5Update(&md5c, cookie, 8); MD5Final(s->session_id, &md5c); for (i = 0; i < 32; i++) ssh->session_key[i] = random_byte(); /* * Verify that the `bits' and `bytes' parameters match. */ if (hostkey.bits > hostkey.bytes * 8 || servkey.bits > servkey.bytes * 8) { bombout(("SSH-1 public keys were badly formatted")); crStop(0); } s->len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes); s->rsabuf = snewn(s->len, unsigned char); if (!s->rsabuf) fatalbox("Out of memory"); /* * Verify the host key. */ { /* * First format the key into a string. */ int len = rsastr_len(&hostkey); char fingerprint[100]; char *keystr = snewn(len, char); if (!keystr) fatalbox("Out of memory"); rsastr_fmt(keystr, &hostkey); rsa_fingerprint(fingerprint, sizeof(fingerprint), &hostkey); ssh_set_frozen(ssh, 1); s->dlgret = verify_ssh_host_key(ssh->frontend, ssh->savedhost, ssh->savedport, "rsa", keystr, fingerprint, ssh_dialog_callback, ssh); sfree(keystr); if (s->dlgret < 0) { do { crReturn(0); if (pktin) { bombout(("Unexpected data from server while waiting" " for user host key response")); crStop(0); } } while (pktin || inlen > 0); s->dlgret = ssh->user_response; } ssh_set_frozen(ssh, 0); if (s->dlgret == 0) { ssh->close_expected = TRUE; ssh_closing((Plug)ssh, NULL, 0, 0); crStop(0); } } for (i = 0; i < 32; i++) { s->rsabuf[i] = ssh->session_key[i]; if (i < 16) s->rsabuf[i] ^= s->session_id[i]; } if (hostkey.bytes > servkey.bytes) { ret = rsaencrypt(s->rsabuf, 32, &servkey); if (ret) ret = rsaencrypt(s->rsabuf, servkey.bytes, &hostkey); } else { ret = rsaencrypt(s->rsabuf, 32, &hostkey); if (ret) ret = rsaencrypt(s->rsabuf, hostkey.bytes, &servkey); } if (!ret) { bombout(("SSH-1 public key encryptions failed due to bad formatting")); crStop(0); } logevent("Encrypted session key"); { int cipher_chosen = 0, warn = 0; char *cipher_string = NULL; int i; for (i = 0; !cipher_chosen && i < CIPHER_MAX; i++) { int next_cipher = ssh->cfg.ssh_cipherlist[i]; if (next_cipher == CIPHER_WARN) { /* If/when we choose a cipher, warn about it */ warn = 1; } else if (next_cipher == CIPHER_AES) { /* XXX Probably don't need to mention this. */ logevent("AES not supported in SSH-1, skipping"); } else { switch (next_cipher) { case CIPHER_3DES: s->cipher_type = SSH_CIPHER_3DES; cipher_string = "3DES"; break; case CIPHER_BLOWFISH: s->cipher_type = SSH_CIPHER_BLOWFISH; cipher_string = "Blowfish"; break; case CIPHER_DES: s->cipher_type = SSH_CIPHER_DES; cipher_string = "single-DES"; break; } if (s->supported_ciphers_mask & (1 << s->cipher_type)) cipher_chosen = 1; } } if (!cipher_chosen) { if ((s->supported_ciphers_mask & (1 << SSH_CIPHER_3DES)) == 0) bombout(("Server violates SSH-1 protocol by not " "supporting 3DES encryption")); else /* shouldn't happen */ bombout(("No supported ciphers found")); crStop(0); } /* Warn about chosen cipher if necessary. */ if (warn) { ssh_set_frozen(ssh, 1); s->dlgret = askalg(ssh->frontend, "cipher", cipher_string, ssh_dialog_callback, ssh); if (s->dlgret < 0) { do { crReturn(0); if (pktin) { bombout(("Unexpected data from server while waiting" " for user response")); crStop(0); } } while (pktin || inlen > 0); s->dlgret = ssh->user_response; } ssh_set_frozen(ssh, 0); if (s->dlgret == 0) { ssh->close_expected = TRUE; ssh_closing((Plug)ssh, NULL, 0, 0); crStop(0); } } } switch (s->cipher_type) { case SSH_CIPHER_3DES: logevent("Using 3DES encryption"); break; case SSH_CIPHER_DES: logevent("Using single-DES encryption"); break; case SSH_CIPHER_BLOWFISH: logevent("Using Blowfish encryption"); break; } send_packet(ssh, SSH1_CMSG_SESSION_KEY, PKT_CHAR, s->cipher_type, PKT_DATA, cookie, 8, PKT_CHAR, (s->len * 8) >> 8, PKT_CHAR, (s->len * 8) & 0xFF, PKT_DATA, s->rsabuf, s->len, PKT_INT, ssh->v1_local_protoflags, PKT_END); logevent("Trying to enable encryption..."); sfree(s->rsabuf); ssh->cipher = (s->cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 : s->cipher_type == SSH_CIPHER_DES ? &ssh_des : &ssh_3des); ssh->v1_cipher_ctx = ssh->cipher->make_context(); ssh->cipher->sesskey(ssh->v1_cipher_ctx, ssh->session_key); logeventf(ssh, "Initialised %s encryption", ssh->cipher->text_name); ssh->crcda_ctx = crcda_make_context(); logevent("Installing CRC compensation attack detector"); if (servkey.modulus) { sfree(servkey.modulus); servkey.modulus = NULL; } if (servkey.exponent) { sfree(servkey.exponent); servkey.exponent = NULL; } if (hostkey.modulus) { sfree(hostkey.modulus); hostkey.modulus = NULL; } if (hostkey.exponent) { sfree(hostkey.exponent); hostkey.exponent = NULL; } crWaitUntil(pktin); if (pktin->type != SSH1_SMSG_SUCCESS) { bombout(("Encryption not successfully enabled")); crStop(0); } logevent("Successfully started encryption"); fflush(stdout); { if (!*ssh->cfg.username) { if (ssh_get_line && !ssh_getline_pw_only) { if (!ssh_get_line("login as: ", s->username, sizeof(s->username), FALSE)) { /* * get_line failed to get a username. * Terminate. */ logevent("No username provided. Abandoning session."); ssh->close_expected = TRUE; ssh_closing((Plug)ssh, NULL, 0, 0); crStop(1); } } else { int ret; /* need not be kept over crReturn */ c_write_str(ssh, "login as: "); ssh->send_ok = 1; setup_userpass_input(ssh, s->username, sizeof(s->username), 1); do { crWaitUntil(!pktin); ret = process_userpass_input(ssh, in, inlen); } while (ret == 0); if (ret < 0) cleanup_exit(0); c_write_str(ssh, "\r\n"); } } else { strncpy(s->username, ssh->cfg.username, sizeof(s->username)); s->username[sizeof(s->username)-1] = '\0'; } send_packet(ssh, SSH1_CMSG_USER, PKT_STR, s->username, PKT_END); { char userlog[22 + sizeof(s->username)]; sprintf(userlog, "Sent username \"%s\"", s->username); logevent(userlog); if (flags & FLAG_INTERACTIVE && (!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) { strcat(userlog, "\r\n"); c_write_str(ssh, userlog); } } } crWaitUntil(pktin); if ((ssh->remote_bugs & BUG_CHOKES_ON_RSA)) { /* We must not attempt PK auth. Pretend we've already tried it. */ s->tried_publickey = s->tried_agent = 1; } else { s->tried_publickey = s->tried_agent = 0; } s->tis_auth_refused = s->ccard_auth_refused = 0; /* Load the public half of ssh->cfg.keyfile so we notice if it's in Pageant */ if (!filename_is_null(ssh->cfg.keyfile)) { if (!rsakey_pubblob(&ssh->cfg.keyfile, &s->publickey_blob, &s->publickey_bloblen, NULL)) s->publickey_blob = NULL; } else s->publickey_blob = NULL; while (pktin->type == SSH1_SMSG_FAILURE) { s->pwpkt_type = SSH1_CMSG_AUTH_PASSWORD; if (agent_exists() && !s->tried_agent) { /* * Attempt RSA authentication using Pageant. */ void *r; s->authed = FALSE; s->tried_agent = 1; logevent("Pageant is running. Requesting keys."); /* Request the keys held by the agent. */ PUT_32BIT(s->request, 1); s->request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES; if (!agent_query(s->request, 5, &r, &s->responselen, ssh_agent_callback, ssh)) { do { crReturn(0); if (pktin) { bombout(("Unexpected data from server while waiting" " for agent response")); crStop(0); } } while (pktin || inlen > 0); r = ssh->agent_response; s->responselen = ssh->agent_response_len; } s->response = (unsigned char *) r; if (s->response && s->responselen >= 5 && s->response[4] == SSH1_AGENT_RSA_IDENTITIES_ANSWER) { s->p = s->response + 5; s->nkeys = GET_32BIT(s->p); s->p += 4; logeventf(ssh, "Pageant has %d SSH-1 keys", s->nkeys); for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) { logeventf(ssh, "Trying Pageant key #%d", s->keyi); if (s->publickey_blob && !memcmp(s->p, s->publickey_blob, s->publickey_bloblen)) { logevent("This key matches configured key file"); s->tried_publickey = 1; } s->p += 4; { int n, ok = FALSE; do { /* do while (0) to make breaking easy */ n = ssh1_read_bignum (s->p, s->responselen-(s->p-s->response), &s->key.exponent); if (n < 0) break; s->p += n; n = ssh1_read_bignum (s->p, s->responselen-(s->p-s->response), &s->key.modulus); if (n < 0) break; s->p += n; if (s->responselen - (s->p-s->response) < 4) break; s->commentlen = GET_32BIT(s->p); s->p += 4; if (s->responselen - (s->p-s->response) < s->commentlen) break; s->commentp = (char *)s->p; s->p += s->commentlen; ok = TRUE; } while (0); if (!ok) { logevent("Pageant key list packet was truncated"); break; } } send_packet(ssh, SSH1_CMSG_AUTH_RSA, PKT_BIGNUM, s->key.modulus, PKT_END); crWaitUntil(pktin); if (pktin->type != SSH1_SMSG_AUTH_RSA_CHALLENGE) { logevent("Key refused"); continue; } logevent("Received RSA challenge"); if ((s->challenge = ssh1_pkt_getmp(pktin)) == NULL) { bombout(("Server's RSA challenge was badly formatted")); crStop(0); } { char *agentreq, *q, *ret; void *vret; int len, retlen; len = 1 + 4; /* message type, bit count */ len += ssh1_bignum_length(s->key.exponent); len += ssh1_bignum_length(s->key.modulus); len += ssh1_bignum_length(s->challenge); len += 16; /* session id */ len += 4; /* response format */ agentreq = snewn(4 + len, char); PUT_32BIT(agentreq, len); q = agentreq + 4; *q++ = SSH1_AGENTC_RSA_CHALLENGE; PUT_32BIT(q, bignum_bitcount(s->key.modulus)); q += 4; q += ssh1_write_bignum(q, s->key.exponent); q += ssh1_write_bignum(q, s->key.modulus); q += ssh1_write_bignum(q, s->challenge); memcpy(q, s->session_id, 16); q += 16; PUT_32BIT(q, 1); /* response format */ if (!agent_query(agentreq, len + 4, &vret, &retlen, ssh_agent_callback, ssh)) { sfree(agentreq); do { crReturn(0); if (pktin) { bombout(("Unexpected data from server" " while waiting for agent" " response")); crStop(0); } } while (pktin || inlen > 0); vret = ssh->agent_response; retlen = ssh->agent_response_len; } else sfree(agentreq); ret = vret; if (ret) { if (ret[4] == SSH1_AGENT_RSA_RESPONSE) { logevent("Sending Pageant's response"); send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE, PKT_DATA, ret + 5, 16, PKT_END); sfree(ret); crWaitUntil(pktin); if (pktin->type == SSH1_SMSG_SUCCESS) { logevent ("Pageant's response accepted"); if (flags & FLAG_VERBOSE) { c_write_str(ssh, "Authenticated using" " RSA key \""); c_write(ssh, s->commentp, s->commentlen); c_write_str(ssh, "\" from agent\r\n"); } s->authed = TRUE; } else logevent ("Pageant's response not accepted"); } else { logevent ("Pageant failed to answer challenge"); sfree(ret); } } else { logevent("No reply received from Pageant"); } } freebn(s->key.exponent); freebn(s->key.modulus); freebn(s->challenge); if (s->authed) break; } sfree(s->response); } if (s->authed) break; } if (!filename_is_null(ssh->cfg.keyfile) && !s->tried_publickey) s->pwpkt_type = SSH1_CMSG_AUTH_RSA; if (ssh->cfg.try_tis_auth && (s->supported_auths_mask & (1 << SSH1_AUTH_TIS)) && !s->tis_auth_refused) { s->pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE; logevent("Requested TIS authentication"); send_packet(ssh, SSH1_CMSG_AUTH_TIS, PKT_END); crWaitUntil(pktin); if (pktin->type != SSH1_SMSG_AUTH_TIS_CHALLENGE) { logevent("TIS authentication declined"); if (flags & FLAG_INTERACTIVE) c_write_str(ssh, "TIS authentication refused.\r\n"); s->tis_auth_refused = 1; continue; } else { char *challenge; int challengelen; ssh_pkt_getstring(pktin, &challenge, &challengelen); if (!challenge) { bombout(("TIS challenge packet was badly formed")); crStop(0); } c_write_str(ssh, "Using TIS authentication.\r\n"); logevent("Received TIS challenge"); if (challengelen > sizeof(s->prompt) - 1) challengelen = sizeof(s->prompt) - 1;/* prevent overrun */ memcpy(s->prompt, challenge, challengelen); /* Prompt heuristic comes from OpenSSH */ strncpy(s->prompt + challengelen, memchr(s->prompt, '\n', challengelen) ? "": "\r\nResponse: ", (sizeof s->prompt) - challengelen); s->prompt[(sizeof s->prompt) - 1] = '\0'; } } if (ssh->cfg.try_tis_auth && (s->supported_auths_mask & (1 << SSH1_AUTH_CCARD)) && !s->ccard_auth_refused) { s->pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE; logevent("Requested CryptoCard authentication"); send_packet(ssh, SSH1_CMSG_AUTH_CCARD, PKT_END); crWaitUntil(pktin); if (pktin->type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) { logevent("CryptoCard authentication declined"); c_write_str(ssh, "CryptoCard authentication refused.\r\n"); s->ccard_auth_refused = 1; continue; } else { char *challenge; int challengelen; ssh_pkt_getstring(pktin, &challenge, &challengelen); if (!challenge) { bombout(("CryptoCard challenge packet was badly formed")); crStop(0); } c_write_str(ssh, "Using CryptoCard authentication.\r\n"); logevent("Received CryptoCard challenge"); if (challengelen > sizeof(s->prompt) - 1) challengelen = sizeof(s->prompt) - 1;/* prevent overrun */ memcpy(s->prompt, challenge, challengelen); strncpy(s->prompt + challengelen, memchr(s->prompt, '\n', challengelen) ? "" : "\r\nResponse: ", sizeof(s->prompt) - challengelen); s->prompt[sizeof(s->prompt) - 1] = '\0'; } } if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) { sprintf(s->prompt, "%.90s@%.90s's password: ", s->username, ssh->savedhost); } if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) { char *comment = NULL; int type; if (flags & FLAG_VERBOSE) c_write_str(ssh, "Trying public key authentication.\r\n"); logeventf(ssh, "Trying public key \"%s\"", filename_to_str(&ssh->cfg.keyfile)); type = key_type(&ssh->cfg.keyfile); if (type != SSH_KEYTYPE_SSH1) { char *msg = dupprintf("Key is of wrong type (%s)", key_type_to_str(type)); logevent(msg); c_write_str(ssh, msg); c_write_str(ssh, "\r\n"); sfree(msg); s->tried_publickey = 1; continue; } if (!rsakey_encrypted(&ssh->cfg.keyfile, &comment)) { if (flags & FLAG_VERBOSE) c_write_str(ssh, "No passphrase required.\r\n"); goto tryauth; } sprintf(s->prompt, "Passphrase for key \"%.100s\": ", comment); sfree(comment); } /* * Show password prompt, having first obtained it via a TIS * or CryptoCard exchange if we're doing TIS or CryptoCard * authentication. */ if (ssh_get_line) { if (!ssh_get_line(s->prompt, s->password, sizeof(s->password), TRUE)) { /* * get_line failed to get a password (for example * because one was supplied on the command line * which has already failed to work). Terminate. */ send_packet(ssh, SSH1_MSG_DISCONNECT, PKT_STR, "No more passwords available to try", PKT_END); logevent("Unable to authenticate"); connection_fatal(ssh->frontend, "Unable to authenticate"); ssh->close_expected = TRUE; ssh_closing((Plug)ssh, NULL, 0, 0); crStop(1); } } else { /* Prompt may have come from server. We've munged it a bit, so * we know it to be zero-terminated at least once. */ int ret; /* need not be saved over crReturn */ c_write_untrusted(ssh, s->prompt, strlen(s->prompt)); s->pos = 0; setup_userpass_input(ssh, s->password, sizeof(s->password), 0); do { crWaitUntil(!pktin); ret = process_userpass_input(ssh, in, inlen); } while (ret == 0); if (ret < 0) cleanup_exit(0); c_write_str(ssh, "\r\n"); } tryauth: if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) { /* * Try public key authentication with the specified * key file. */ s->tried_publickey = 1; { const char *error = NULL; int ret = loadrsakey(&ssh->cfg.keyfile, &s->key, s->password, &error); if (ret == 0) { c_write_str(ssh, "Couldn't load private key from "); c_write_str(ssh, filename_to_str(&ssh->cfg.keyfile)); c_write_str(ssh, " ("); c_write_str(ssh, error); c_write_str(ssh, ").\r\n"); continue; /* go and try password */ } if (ret == -1) { c_write_str(ssh, "Wrong passphrase.\r\n"); s->tried_publickey = 0; continue; /* try again */ } } /* * Send a public key attempt. */ send_packet(ssh, SSH1_CMSG_AUTH_RSA, PKT_BIGNUM, s->key.modulus, PKT_END); crWaitUntil(pktin); if (pktin->type == SSH1_SMSG_FAILURE) { c_write_str(ssh, "Server refused our public key.\r\n"); continue; /* go and try password */ } if (pktin->type != SSH1_SMSG_AUTH_RSA_CHALLENGE) { bombout(("Bizarre response to offer of public key")); crStop(0); } { int i; unsigned char buffer[32]; Bignum challenge, response; if ((challenge = ssh1_pkt_getmp(pktin)) == NULL) { bombout(("Server's RSA challenge was badly formatted")); crStop(0); } response = rsadecrypt(challenge, &s->key); freebn(s->key.private_exponent);/* burn the evidence */ for (i = 0; i < 32; i++) { buffer[i] = bignum_byte(response, 31 - i); } MD5Init(&md5c); MD5Update(&md5c, buffer, 32); MD5Update(&md5c, s->session_id, 16); MD5Final(buffer, &md5c); send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE, PKT_DATA, buffer, 16, PKT_END); freebn(challenge); freebn(response); } crWaitUntil(pktin); if (pktin->type == SSH1_SMSG_FAILURE) { if (flags & FLAG_VERBOSE) c_write_str(ssh, "Failed to authenticate with" " our public key.\r\n"); continue; /* go and try password */ } else if (pktin->type != SSH1_SMSG_SUCCESS) { bombout(("Bizarre response to RSA authentication response")); crStop(0); } break; /* we're through! */ } else { if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) { /* * Defence against traffic analysis: we send a * whole bunch of packets containing strings of * different lengths. One of these strings is the * password, in a SSH1_CMSG_AUTH_PASSWORD packet. * The others are all random data in * SSH1_MSG_IGNORE packets. This way a passive * listener can't tell which is the password, and * hence can't deduce the password length. * * Anybody with a password length greater than 16 * bytes is going to have enough entropy in their * password that a listener won't find it _that_ * much help to know how long it is. So what we'll * do is: * * - if password length < 16, we send 15 packets * containing string lengths 1 through 15 * * - otherwise, we let N be the nearest multiple * of 8 below the password length, and send 8 * packets containing string lengths N through * N+7. This won't obscure the order of * magnitude of the password length, but it will * introduce a bit of extra uncertainty. * * A few servers (the old 1.2.18 through 1.2.22) * can't deal with SSH1_MSG_IGNORE. For these * servers, we need an alternative defence. We make * use of the fact that the password is interpreted * as a C string: so we can append a NUL, then some * random data. * * One server (a Cisco one) can deal with neither * SSH1_MSG_IGNORE _nor_ a padded password string. * For this server we are left with no defences * against password length sniffing. */ if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE)) { /* * The server can deal with SSH1_MSG_IGNORE, so * we can use the primary defence. */ int bottom, top, pwlen, i; char *randomstr; pwlen = strlen(s->password); if (pwlen < 16) { bottom = 0; /* zero length passwords are OK! :-) */ top = 15; } else { bottom = pwlen & ~7; top = bottom + 7; } assert(pwlen >= bottom && pwlen <= top); randomstr = snewn(top + 1, char); for (i = bottom; i <= top; i++) { if (i == pwlen) { defer_packet(ssh, s->pwpkt_type, PKTT_PASSWORD, PKT_STR, s->password, PKTT_OTHER, PKT_END); } else { for (j = 0; j < i; j++) { do { randomstr[j] = random_byte(); } while (randomstr[j] == '\0'); } randomstr[i] = '\0'; defer_packet(ssh, SSH1_MSG_IGNORE, PKT_STR, randomstr, PKT_END); } } logevent("Sending password with camouflage packets"); ssh_pkt_defersend(ssh); sfree(randomstr); } else if (!(ssh->remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) { /* * The server can't deal with SSH1_MSG_IGNORE * but can deal with padded passwords, so we * can use the secondary defence. */ char string[64]; char *ss; int len; len = strlen(s->password); if (len < sizeof(string)) { ss = string; strcpy(string, s->password); len++; /* cover the zero byte */ while (len < sizeof(string)) { string[len++] = (char) random_byte(); } } else { ss = s->password; } logevent("Sending length-padded password"); send_packet(ssh, s->pwpkt_type, PKTT_PASSWORD, PKT_INT, len, PKT_DATA, ss, len, PKTT_OTHER, PKT_END); } else { /* * The server has _both_ * BUG_CHOKES_ON_SSH1_IGNORE and * BUG_NEEDS_SSH1_PLAIN_PASSWORD. There is * therefore nothing we can do. */ int len; len = strlen(s->password); logevent("Sending unpadded password"); send_packet(ssh, s->pwpkt_type, PKTT_PASSWORD, PKT_INT, len, PKT_DATA, s->password, len, PKTT_OTHER, PKT_END); } } else { send_packet(ssh, s->pwpkt_type, PKTT_PASSWORD, PKT_STR, s->password, PKTT_OTHER, PKT_END); } } logevent("Sent password"); memset(s->password, 0, strlen(s->password)); crWaitUntil(pktin); if (pktin->type == SSH1_SMSG_FAILURE) { if (flags & FLAG_VERBOSE) c_write_str(ssh, "Access denied\r\n"); logevent("Authentication refused"); } else if (pktin->type != SSH1_SMSG_SUCCESS) { bombout(("Strange packet received, type %d", pktin->type)); crStop(0); } } logevent("Authentication successful"); crFinish(1); } void sshfwd_close(struct ssh_channel *c) { Ssh ssh = c->ssh; if (ssh->state == SSH_STATE_CLOSED) return; if (c && !c->closes) { /* * If halfopen is true, we have sent * CHANNEL_OPEN for this channel, but it hasn't even been * acknowledged by the server. So we must set a close flag * on it now, and then when the server acks the channel * open, we can close it then. */ if (!c->halfopen) { if (ssh->version == 1) { send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid, PKT_END); } else { struct Packet *pktout; pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE); ssh2_pkt_adduint32(pktout, c->remoteid); ssh2_pkt_send(ssh, pktout); } } c->closes = 1; /* sent MSG_CLOSE */ if (c->type == CHAN_X11) { c->u.x11.s = NULL; logevent("Forwarded X11 connection terminated"); } else if (c->type == CHAN_SOCKDATA || c->type == CHAN_SOCKDATA_DORMANT) { c->u.pfd.s = NULL; logevent("Forwarded port closed"); } } } int sshfwd_write(struct ssh_channel *c, char *buf, int len) { Ssh ssh = c->ssh; if (ssh->state == SSH_STATE_CLOSED) return 0; if (ssh->version == 1) { send_packet(ssh, SSH1_MSG_CHANNEL_DATA, PKT_INT, c->remoteid, PKTT_DATA, PKT_INT, len, PKT_DATA, buf, len, PKTT_OTHER, PKT_END); /* * In SSH-1 we can return 0 here - implying that forwarded * connections are never individually throttled - because * the only circumstance that can cause throttling will be * the whole SSH connection backing up, in which case * _everything_ will be throttled as a whole. */ return 0; } else { ssh2_add_channel_data(c, buf, len); return ssh2_try_send(c); } } void sshfwd_unthrottle(struct ssh_channel *c, int bufsize) { Ssh ssh = c->ssh; if (ssh->state == SSH_STATE_CLOSED) return; if (ssh->version == 1) { if (c->v.v1.throttling && bufsize < SSH1_BUFFER_LIMIT) { c->v.v1.throttling = 0; ssh1_throttle(ssh, -1); } } else { ssh2_set_window(c, OUR_V2_WINSIZE - bufsize); } } static void ssh_queueing_handler(Ssh ssh, struct Packet *pktin) { struct queued_handler *qh = ssh->qhead; assert(qh != NULL); assert(pktin->type == qh->msg1 || pktin->type == qh->msg2); if (qh->msg1 > 0) { assert(ssh->packet_dispatch[qh->msg1] == ssh_queueing_handler); ssh->packet_dispatch[qh->msg1] = NULL; } if (qh->msg2 > 0) { assert(ssh->packet_dispatch[qh->msg2] == ssh_queueing_handler); ssh->packet_dispatch[qh->msg2] = NULL; } if (qh->next) { ssh->qhead = qh->next; if (ssh->qhead->msg1 > 0) { assert(ssh->packet_dispatch[ssh->qhead->msg1] == NULL); ssh->packet_dispatch[ssh->qhead->msg1] = ssh_queueing_handler; } if (ssh->qhead->msg2 > 0) { assert(ssh->packet_dispatch[ssh->qhead->msg2] == NULL); ssh->packet_dispatch[ssh->qhead->msg2] = ssh_queueing_handler; } } else { ssh->qhead = ssh->qtail = NULL; ssh->packet_dispatch[pktin->type] = NULL; } qh->handler(ssh, pktin, qh->ctx); sfree(qh); } static void ssh_queue_handler(Ssh ssh, int msg1, int msg2, chandler_fn_t handler, void *ctx) { struct queued_handler *qh; qh = snew(struct queued_handler); qh->msg1 = msg1; qh->msg2 = msg2; qh->handler = handler; qh->ctx = ctx; qh->next = NULL; if (ssh->qtail == NULL) { ssh->qhead = qh; if (qh->msg1 > 0) { assert(ssh->packet_dispatch[qh->msg1] == NULL); ssh->packet_dispatch[qh->msg1] = ssh_queueing_handler; } if (qh->msg2 > 0) { assert(ssh->packet_dispatch[qh->msg2] == NULL); ssh->packet_dispatch[qh->msg2] = ssh_queueing_handler; } } else { ssh->qtail->next = qh; } ssh->qtail = qh; } static void ssh_rportfwd_succfail(Ssh ssh, struct Packet *pktin, void *ctx) { struct ssh_rportfwd *rpf, *pf = (struct ssh_rportfwd *)ctx; if (pktin->type == (ssh->version == 1 ? SSH1_SMSG_SUCCESS : SSH2_MSG_REQUEST_SUCCESS)) { logeventf(ssh, "Remote port forwarding from %s enabled", pf->sportdesc); } else { logeventf(ssh, "Remote port forwarding from %s refused", pf->sportdesc); rpf = del234(ssh->rportfwds, pf); assert(rpf == pf); free_rportfwd(pf); } } static void ssh_setup_portfwd(Ssh ssh, const Config *cfg) { const char *portfwd_strptr = cfg->portfwd; struct ssh_portfwd *epf; int i; if (!ssh->portfwds) { ssh->portfwds = newtree234(ssh_portcmp); } else { /* * Go through the existing port forwardings and tag them * with status==DESTROY. Any that we want to keep will be * re-enabled (status==KEEP) as we go through the * configuration and find out which bits are the same as * they were before. */ struct ssh_portfwd *epf; int i; for (i = 0; (epf = index234(ssh->portfwds, i)) != NULL; i++) epf->status = DESTROY; } while (*portfwd_strptr) { char address_family, type; int sport,dport,sserv,dserv; char sports[256], dports[256], saddr[256], host[256]; int n; address_family = 'A'; type = 'L'; if (*portfwd_strptr == 'A' || *portfwd_strptr == '4' || *portfwd_strptr == '6') address_family = *portfwd_strptr++; if (*portfwd_strptr == 'L' || *portfwd_strptr == 'R' || *portfwd_strptr == 'D') type = *portfwd_strptr++; saddr[0] = '\0'; n = 0; while (*portfwd_strptr && *portfwd_strptr != '\t') { if (*portfwd_strptr == ':') { /* * We've seen a colon in the middle of the * source port number. This means that * everything we've seen until now is the * source _address_, so we'll move it into * saddr and start sports from the beginning * again. */ portfwd_strptr++; sports[n] = '\0'; if (ssh->version == 1 && type == 'R') { logeventf(ssh, "SSH-1 cannot handle remote source address " "spec \"%s\"; ignoring", sports); } else strcpy(saddr, sports); n = 0; } if (n < lenof(sports)-1) sports[n++] = *portfwd_strptr++; } sports[n] = 0; if (type != 'D') { if (*portfwd_strptr == '\t') portfwd_strptr++; n = 0; while (*portfwd_strptr && *portfwd_strptr != ':') { if (n < lenof(host)-1) host[n++] = *portfwd_strptr++; } host[n] = 0; if (*portfwd_strptr == ':') portfwd_strptr++; n = 0; while (*portfwd_strptr) { if (n < lenof(dports)-1) dports[n++] = *portfwd_strptr++; } dports[n] = 0; portfwd_strptr++; dport = atoi(dports); dserv = 0; if (dport == 0) { dserv = 1; dport = net_service_lookup(dports); if (!dport) { logeventf(ssh, "Service lookup failed for destination" " port \"%s\"", dports); } } } else { while (*portfwd_strptr) portfwd_strptr++; host[0] = 0; dports[0] = 0; dport = dserv = -1; portfwd_strptr++; /* eat the NUL and move to next one */ } sport = atoi(sports); sserv = 0; if (sport == 0) { sserv = 1; sport = net_service_lookup(sports); if (!sport) { logeventf(ssh, "Service lookup failed for source" " port \"%s\"", sports); } } if (sport && dport) { /* Set up a description of the source port. */ struct ssh_portfwd *pfrec, *epfrec; pfrec = snew(struct ssh_portfwd); pfrec->type = type; pfrec->saddr = *saddr ? dupstr(saddr) : NULL; pfrec->sserv = sserv ? dupstr(sports) : NULL; pfrec->sport = sport; pfrec->daddr = *host ? dupstr(host) : NULL; pfrec->dserv = dserv ? dupstr(dports) : NULL; pfrec->dport = dport; pfrec->local = NULL; pfrec->remote = NULL; pfrec->addressfamily = (address_family == '4' ? ADDRTYPE_IPV4 : address_family == '6' ? ADDRTYPE_IPV6 : ADDRTYPE_UNSPEC); epfrec = add234(ssh->portfwds, pfrec); if (epfrec != pfrec) { /* * We already have a port forwarding with precisely * these parameters. Hence, no need to do anything; * simply tag the existing one as KEEP. */ epfrec->status = KEEP; free_portfwd(pfrec); } else { pfrec->status = CREATE; } } } /* * Now go through and destroy any port forwardings which were * not re-enabled. */ for (i = 0; (epf = index234(ssh->portfwds, i)) != NULL; i++) if (epf->status == DESTROY) { char *message; message = dupprintf("%s port forwarding from %s%s%d", epf->type == 'L' ? "local" : epf->type == 'R' ? "remote" : "dynamic", epf->saddr ? epf->saddr : "", epf->saddr ? ":" : "", epf->sport); if (epf->type != 'D') { char *msg2 = dupprintf("%s to %s:%d", message, epf->daddr, epf->dport); sfree(message); message = msg2; } logeventf(ssh, "Cancelling %s", message); sfree(message); if (epf->remote) { struct ssh_rportfwd *rpf = epf->remote; struct Packet *pktout; /* * Cancel the port forwarding at the server * end. */ if (ssh->version == 1) { /* * We cannot cancel listening ports on the * server side in SSH-1! There's no message * to support it. Instead, we simply remove * the rportfwd record from the local end * so that any connections the server tries * to make on it are rejected. */ } else { pktout = ssh2_pkt_init(SSH2_MSG_GLOBAL_REQUEST); ssh2_pkt_addstring(pktout, "cancel-tcpip-forward"); ssh2_pkt_addbool(pktout, 0);/* _don't_ want reply */ if (epf->saddr) { ssh2_pkt_addstring(pktout, epf->saddr); } else if (ssh->cfg.rport_acceptall) { /* XXX: ssh->cfg.rport_acceptall may not represent * what was used to open the original connection, * since it's reconfigurable. */ ssh2_pkt_addstring(pktout, "0.0.0.0"); } else { ssh2_pkt_addstring(pktout, "127.0.0.1"); } ssh2_pkt_adduint32(pktout, epf->sport); ssh2_pkt_send(ssh, pktout); } del234(ssh->rportfwds, rpf); free_rportfwd(rpf); } else if (epf->local) { pfd_terminate(epf->local); } delpos234(ssh->portfwds, i); free_portfwd(epf); i--; /* so we don't skip one in the list */ } /* * And finally, set up any new port forwardings (status==CREATE). */ for (i = 0; (epf = index234(ssh->portfwds, i)) != NULL; i++) if (epf->status == CREATE) { char *sportdesc, *dportdesc; sportdesc = dupprintf("%s%s%s%s%d%s", epf->saddr ? epf->saddr : "", epf->saddr ? ":" : "", epf->sserv ? epf->sserv : "", epf->sserv ? "(" : "", epf->sport, epf->sserv ? ")" : ""); if (epf->type == 'D') { dportdesc = NULL; } else { dportdesc = dupprintf("%s:%s%s%d%s", epf->daddr, epf->dserv ? epf->dserv : "", epf->dserv ? "(" : "", epf->dport, epf->dserv ? ")" : ""); } if (epf->type == 'L') { const char *err = pfd_addforward(epf->daddr, epf->dport, epf->saddr, epf->sport, ssh, cfg, &epf->local, epf->addressfamily); logeventf(ssh, "Local %sport %s forwarding to %s%s%s", epf->addressfamily == ADDRTYPE_IPV4 ? "IPv4 " : epf->addressfamily == ADDRTYPE_IPV6 ? "IPv6 " : "", sportdesc, dportdesc, err ? " failed: " : "", err ? err : ""); } else if (epf->type == 'D') { const char *err = pfd_addforward(NULL, -1, epf->saddr, epf->sport, ssh, cfg, &epf->local, epf->addressfamily); logeventf(ssh, "Local %sport %s SOCKS dynamic forwarding%s%s", epf->addressfamily == ADDRTYPE_IPV4 ? "IPv4 " : epf->addressfamily == ADDRTYPE_IPV6 ? "IPv6 " : "", sportdesc, err ? " failed: " : "", err ? err : ""); } else { struct ssh_rportfwd *pf; /* * Ensure the remote port forwardings tree exists. */ if (!ssh->rportfwds) { if (ssh->version == 1) ssh->rportfwds = newtree234(ssh_rportcmp_ssh1); else ssh->rportfwds = newtree234(ssh_rportcmp_ssh2); } pf = snew(struct ssh_rportfwd); strncpy(pf->dhost, epf->daddr, lenof(pf->dhost)-1); pf->dhost[lenof(pf->dhost)-1] = '\0'; pf->dport = epf->dport; pf->sport = epf->sport; if (add234(ssh->rportfwds, pf) != pf) { logeventf(ssh, "Duplicate remote port forwarding to %s:%d", epf->daddr, epf->dport); sfree(pf); } else { logeventf(ssh, "Requesting remote port %s" " forward to %s", sportdesc, dportdesc); pf->sportdesc = sportdesc; sportdesc = NULL; epf->remote = pf; pf->pfrec = epf; if (ssh->version == 1) { send_packet(ssh, SSH1_CMSG_PORT_FORWARD_REQUEST, PKT_INT, epf->sport, PKT_STR, epf->daddr, PKT_INT, epf->dport, PKT_END); ssh_queue_handler(ssh, SSH1_SMSG_SUCCESS, SSH1_SMSG_FAILURE, ssh_rportfwd_succfail, pf); } else { struct Packet *pktout; pktout = ssh2_pkt_init(SSH2_MSG_GLOBAL_REQUEST); ssh2_pkt_addstring(pktout, "tcpip-forward"); ssh2_pkt_addbool(pktout, 1);/* want reply */ if (epf->saddr) { ssh2_pkt_addstring(pktout, epf->saddr); } else if (cfg->rport_acceptall) { ssh2_pkt_addstring(pktout, "0.0.0.0"); } else { ssh2_pkt_addstring(pktout, "127.0.0.1"); } ssh2_pkt_adduint32(pktout, epf->sport); ssh2_pkt_send(ssh, pktout); ssh_queue_handler(ssh, SSH2_MSG_REQUEST_SUCCESS, SSH2_MSG_REQUEST_FAILURE, ssh_rportfwd_succfail, pf); } } } sfree(sportdesc); sfree(dportdesc); } } static void ssh1_smsg_stdout_stderr_data(Ssh ssh, struct Packet *pktin) { char *string; int stringlen, bufsize; ssh_pkt_getstring(pktin, &string, &stringlen); if (string == NULL) { bombout(("Incoming terminal data packet was badly formed")); return; } bufsize = from_backend(ssh->frontend, pktin->type == SSH1_SMSG_STDERR_DATA, string, stringlen); if (!ssh->v1_stdout_throttling && bufsize > SSH1_BUFFER_LIMIT) { ssh->v1_stdout_throttling = 1; ssh1_throttle(ssh, +1); } } static void ssh1_smsg_x11_open(Ssh ssh, struct Packet *pktin) { /* Remote side is trying to open a channel to talk to our * X-Server. Give them back a local channel number. */ struct ssh_channel *c; int remoteid = ssh_pkt_getuint32(pktin); logevent("Received X11 connect request"); /* Refuse if X11 forwarding is disabled. */ if (!ssh->X11_fwd_enabled) { send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE, PKT_INT, remoteid, PKT_END); logevent("Rejected X11 connect request"); } else { c = snew(struct ssh_channel); c->ssh = ssh; if (x11_init(&c->u.x11.s, ssh->cfg.x11_display, c, ssh->x11auth, NULL, -1, &ssh->cfg) != NULL) { logevent("Opening X11 forward connection failed"); sfree(c); send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE, PKT_INT, remoteid, PKT_END); } else { logevent ("Opening X11 forward connection succeeded"); c->remoteid = remoteid; c->halfopen = FALSE; c->localid = alloc_channel_id(ssh); c->closes = 0; c->v.v1.throttling = 0; c->type = CHAN_X11; /* identify channel type */ add234(ssh->channels, c); send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION, PKT_INT, c->remoteid, PKT_INT, c->localid, PKT_END); logevent("Opened X11 forward channel"); } } } static void ssh1_smsg_agent_open(Ssh ssh, struct Packet *pktin) { /* Remote side is trying to open a channel to talk to our * agent. Give them back a local channel number. */ struct ssh_channel *c; int remoteid = ssh_pkt_getuint32(pktin); /* Refuse if agent forwarding is disabled. */ if (!ssh->agentfwd_enabled) { send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE, PKT_INT, remoteid, PKT_END); } else { c = snew(struct ssh_channel); c->ssh = ssh; c->remoteid = remoteid; c->halfopen = FALSE; c->localid = alloc_channel_id(ssh); c->closes = 0; c->v.v1.throttling = 0; c->type = CHAN_AGENT; /* identify channel type */ c->u.a.lensofar = 0; add234(ssh->channels, c); send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION, PKT_INT, c->remoteid, PKT_INT, c->localid, PKT_END); } } static void ssh1_msg_port_open(Ssh ssh, struct Packet *pktin) { /* Remote side is trying to open a channel to talk to a * forwarded port. Give them back a local channel number. */ struct ssh_channel *c; struct ssh_rportfwd pf, *pfp; int remoteid; int hostsize, port; char *host; const char *e; c = snew(struct ssh_channel); c->ssh = ssh; remoteid = ssh_pkt_getuint32(pktin); ssh_pkt_getstring(pktin, &host, &hostsize); port = ssh_pkt_getuint32(pktin); if (hostsize >= lenof(pf.dhost)) hostsize = lenof(pf.dhost)-1; memcpy(pf.dhost, host, hostsize); pf.dhost[hostsize] = '\0'; pf.dport = port; pfp = find234(ssh->rportfwds, &pf, NULL); if (pfp == NULL) { logeventf(ssh, "Rejected remote port open request for %s:%d", pf.dhost, port); send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE, PKT_INT, remoteid, PKT_END); } else { logeventf(ssh, "Received remote port open request for %s:%d", pf.dhost, port); e = pfd_newconnect(&c->u.pfd.s, pf.dhost, port, c, &ssh->cfg, pfp->pfrec->addressfamily); if (e != NULL) { logeventf(ssh, "Port open failed: %s", e); sfree(c); send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE, PKT_INT, remoteid, PKT_END); } else { c->remoteid = remoteid; c->halfopen = FALSE; c->localid = alloc_channel_id(ssh); c->closes = 0; c->v.v1.throttling = 0; c->type = CHAN_SOCKDATA; /* identify channel type */ add234(ssh->channels, c); send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION, PKT_INT, c->remoteid, PKT_INT, c->localid, PKT_END); logevent("Forwarded port opened successfully"); } } } static void ssh1_msg_channel_open_confirmation(Ssh ssh, struct Packet *pktin) { unsigned int remoteid = ssh_pkt_getuint32(pktin); unsigned int localid = ssh_pkt_getuint32(pktin); struct ssh_channel *c; c = find234(ssh->channels, &remoteid, ssh_channelfind); if (c && c->type == CHAN_SOCKDATA_DORMANT) { c->remoteid = localid; c->halfopen = FALSE; c->type = CHAN_SOCKDATA; c->v.v1.throttling = 0; pfd_confirm(c->u.pfd.s); } if (c && c->closes) { /* * We have a pending close on this channel, * which we decided on before the server acked * the channel open. So now we know the * remoteid, we can close it again. */ send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid, PKT_END); } } static void ssh1_msg_channel_open_failure(Ssh ssh, struct Packet *pktin) { unsigned int remoteid = ssh_pkt_getuint32(pktin); struct ssh_channel *c; c = find234(ssh->channels, &remoteid, ssh_channelfind); if (c && c->type == CHAN_SOCKDATA_DORMANT) { logevent("Forwarded connection refused by server"); pfd_close(c->u.pfd.s); del234(ssh->channels, c); sfree(c); } } static void ssh1_msg_channel_close(Ssh ssh, struct Packet *pktin) { /* Remote side closes a channel. */ unsigned i = ssh_pkt_getuint32(pktin); struct ssh_channel *c; c = find234(ssh->channels, &i, ssh_channelfind); if (c && !c->halfopen) { int closetype; closetype = (pktin->type == SSH1_MSG_CHANNEL_CLOSE ? 1 : 2); if ((c->closes == 0) && (c->type == CHAN_X11)) { logevent("Forwarded X11 connection terminated"); assert(c->u.x11.s != NULL); x11_close(c->u.x11.s); c->u.x11.s = NULL; } if ((c->closes == 0) && (c->type == CHAN_SOCKDATA)) { logevent("Forwarded port closed"); assert(c->u.pfd.s != NULL); pfd_close(c->u.pfd.s); c->u.pfd.s = NULL; } c->closes |= (closetype << 2); /* seen this message */ if (!(c->closes & closetype)) { send_packet(ssh, pktin->type, PKT_INT, c->remoteid, PKT_END); c->closes |= closetype; /* sent it too */ } if (c->closes == 15) { del234(ssh->channels, c); sfree(c); } } else { bombout(("Received CHANNEL_CLOSE%s for %s channel %d\n", pktin->type == SSH1_MSG_CHANNEL_CLOSE ? "" : "_CONFIRMATION", c ? "half-open" : "nonexistent", i)); } } static void ssh1_msg_channel_data(Ssh ssh, struct Packet *pktin) { /* Data sent down one of our channels. */ int i = ssh_pkt_getuint32(pktin); char *p; int len; struct ssh_channel *c; ssh_pkt_getstring(pktin, &p, &len); c = find234(ssh->channels, &i, ssh_channelfind); if (c) { int bufsize = 0; switch (c->type) { case CHAN_X11: bufsize = x11_send(c->u.x11.s, p, len); break; case CHAN_SOCKDATA: bufsize = pfd_send(c->u.pfd.s, p, len); break; case CHAN_AGENT: /* Data for an agent message. Buffer it. */ while (len > 0) { if (c->u.a.lensofar < 4) { unsigned int l = min(4 - c->u.a.lensofar, len); memcpy(c->u.a.msglen + c->u.a.lensofar, p, l); p += l; len -= l; c->u.a.lensofar += l; } if (c->u.a.lensofar == 4) { c->u.a.totallen = 4 + GET_32BIT(c->u.a.msglen); c->u.a.message = snewn(c->u.a.totallen, unsigned char); memcpy(c->u.a.message, c->u.a.msglen, 4); } if (c->u.a.lensofar >= 4 && len > 0) { unsigned int l = min(c->u.a.totallen - c->u.a.lensofar, len); memcpy(c->u.a.message + c->u.a.lensofar, p, l); p += l; len -= l; c->u.a.lensofar += l; } if (c->u.a.lensofar == c->u.a.totallen) { void *reply; int replylen; if (agent_query(c->u.a.message, c->u.a.totallen, &reply, &replylen, ssh_agentf_callback, c)) ssh_agentf_callback(c, reply, replylen); sfree(c->u.a.message); c->u.a.lensofar = 0; } } bufsize = 0; /* agent channels never back up */ break; } if (!c->v.v1.throttling && bufsize > SSH1_BUFFER_LIMIT) { c->v.v1.throttling = 1; ssh1_throttle(ssh, +1); } } } static void ssh1_smsg_exit_status(Ssh ssh, struct Packet *pktin) { ssh->exitcode = ssh_pkt_getuint32(pktin); logeventf(ssh, "Server sent command exit status %d", ssh->exitcode); send_packet(ssh, SSH1_CMSG_EXIT_CONFIRMATION, PKT_END); /* * In case `helpful' firewalls or proxies tack * extra human-readable text on the end of the * session which we might mistake for another * encrypted packet, we close the session once * we've sent EXIT_CONFIRMATION. */ ssh->close_expected = TRUE; ssh_closing((Plug)ssh, NULL, 0, 0); } static void do_ssh1_connection(Ssh ssh, unsigned char *in, int inlen, struct Packet *pktin) { crBegin(ssh->do_ssh1_connection_crstate); ssh->packet_dispatch[SSH1_SMSG_STDOUT_DATA] = ssh->packet_dispatch[SSH1_SMSG_STDERR_DATA] = ssh1_smsg_stdout_stderr_data; ssh->packet_dispatch[SSH1_MSG_CHANNEL_OPEN_CONFIRMATION] = ssh1_msg_channel_open_confirmation; ssh->packet_dispatch[SSH1_MSG_CHANNEL_OPEN_FAILURE] = ssh1_msg_channel_open_failure; ssh->packet_dispatch[SSH1_MSG_CHANNEL_CLOSE] = ssh->packet_dispatch[SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION] = ssh1_msg_channel_close; ssh->packet_dispatch[SSH1_MSG_CHANNEL_DATA] = ssh1_msg_channel_data; ssh->packet_dispatch[SSH1_SMSG_EXIT_STATUS] = ssh1_smsg_exit_status; if (ssh->cfg.agentfwd && agent_exists()) { logevent("Requesting agent forwarding"); send_packet(ssh, SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END); do { crReturnV; } while (!pktin); if (pktin->type != SSH1_SMSG_SUCCESS && pktin->type != SSH1_SMSG_FAILURE) { bombout(("Protocol confusion")); crStopV; } else if (pktin->type == SSH1_SMSG_FAILURE) { logevent("Agent forwarding refused"); } else { logevent("Agent forwarding enabled"); ssh->agentfwd_enabled = TRUE; ssh->packet_dispatch[SSH1_SMSG_AGENT_OPEN] = ssh1_smsg_agent_open; } } if (ssh->cfg.x11_forward) { char proto[20], data[64]; logevent("Requesting X11 forwarding"); ssh->x11auth = x11_invent_auth(proto, sizeof(proto), data, sizeof(data), ssh->cfg.x11_auth); x11_get_real_auth(ssh->x11auth, ssh->cfg.x11_display); if (ssh->v1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) { send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING, PKT_STR, proto, PKT_STR, data, PKT_INT, x11_get_screen_number(ssh->cfg.x11_display), PKT_END); } else { send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING, PKT_STR, proto, PKT_STR, data, PKT_END); } do { crReturnV; } while (!pktin); if (pktin->type != SSH1_SMSG_SUCCESS && pktin->type != SSH1_SMSG_FAILURE) { bombout(("Protocol confusion")); crStopV; } else if (pktin->type == SSH1_SMSG_FAILURE) { logevent("X11 forwarding refused"); } else { logevent("X11 forwarding enabled"); ssh->X11_fwd_enabled = TRUE; ssh->packet_dispatch[SSH1_SMSG_X11_OPEN] = ssh1_smsg_x11_open; } } ssh_setup_portfwd(ssh, &ssh->cfg); ssh->packet_dispatch[SSH1_MSG_PORT_OPEN] = ssh1_msg_port_open; if (!ssh->cfg.nopty) { /* Unpick the terminal-speed string. */ /* XXX perhaps we should allow no speeds to be sent. */ ssh->ospeed = 38400; ssh->ispeed = 38400; /* last-resort defaults */ sscanf(ssh->cfg.termspeed, "%d,%d", &ssh->ospeed, &ssh->ispeed); /* Send the pty request. */ send_packet(ssh, SSH1_CMSG_REQUEST_PTY, PKT_STR, ssh->cfg.termtype, PKT_INT, ssh->term_height, PKT_INT, ssh->term_width, PKT_INT, 0, PKT_INT, 0, /* width,height in pixels */ PKT_CHAR, 192, PKT_INT, ssh->ispeed, /* TTY_OP_ISPEED */ PKT_CHAR, 193, PKT_INT, ssh->ospeed, /* TTY_OP_OSPEED */ PKT_CHAR, 0, PKT_END); ssh->state = SSH_STATE_INTERMED; do { crReturnV; } while (!pktin); if (pktin->type != SSH1_SMSG_SUCCESS && pktin->type != SSH1_SMSG_FAILURE) { bombout(("Protocol confusion")); crStopV; } else if (pktin->type == SSH1_SMSG_FAILURE) { c_write_str(ssh, "Server refused to allocate pty\r\n"); ssh->editing = ssh->echoing = 1; } logeventf(ssh, "Allocated pty (ospeed %dbps, ispeed %dbps)", ssh->ospeed, ssh->ispeed); } else { ssh->editing = ssh->echoing = 1; } if (ssh->cfg.compression) { send_packet(ssh, SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END); do { crReturnV; } while (!pktin); if (pktin->type != SSH1_SMSG_SUCCESS && pktin->type != SSH1_SMSG_FAILURE) { bombout(("Protocol confusion")); crStopV; } else if (pktin->type == SSH1_SMSG_FAILURE) { c_write_str(ssh, "Server refused to compress\r\n"); } logevent("Started compression"); ssh->v1_compressing = TRUE; ssh->cs_comp_ctx = zlib_compress_init(); logevent("Initialised zlib (RFC1950) compression"); ssh->sc_comp_ctx = zlib_decompress_init(); logevent("Initialised zlib (RFC1950) decompression"); } /* * Start the shell or command. * * Special case: if the first-choice command is an SSH-2 * subsystem (hence not usable here) and the second choice * exists, we fall straight back to that. */ { char *cmd = ssh->cfg.remote_cmd_ptr; if (!cmd) cmd = ssh->cfg.remote_cmd; if (ssh->cfg.ssh_subsys && ssh->cfg.remote_cmd_ptr2) { cmd = ssh->cfg.remote_cmd_ptr2; ssh->fallback_cmd = TRUE; } if (*cmd) send_packet(ssh, SSH1_CMSG_EXEC_CMD, PKT_STR, cmd, PKT_END); else send_packet(ssh, SSH1_CMSG_EXEC_SHELL, PKT_END); logevent("Started session"); } ssh->state = SSH_STATE_SESSION; if (ssh->size_needed) ssh_size(ssh, ssh->term_width, ssh->term_height); if (ssh->eof_needed) ssh_special(ssh, TS_EOF); if (ssh->ldisc) ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */ ssh->send_ok = 1; ssh->channels = newtree234(ssh_channelcmp); while (1) { /* * By this point, most incoming packets are already being * handled by the dispatch table, and we need only pay * attention to the unusual ones. */ crReturnV; if (pktin) { if (pktin->type == SSH1_SMSG_SUCCESS) { /* may be from EXEC_SHELL on some servers */ } else if (pktin->type == SSH1_SMSG_FAILURE) { /* may be from EXEC_SHELL on some servers * if no pty is available or in other odd cases. Ignore */ } else { bombout(("Strange packet received: type %d", pktin->type)); crStopV; } } else { while (inlen > 0) { int len = min(inlen, 512); send_packet(ssh, SSH1_CMSG_STDIN_DATA, PKTT_DATA, PKT_INT, len, PKT_DATA, in, len, PKTT_OTHER, PKT_END); in += len; inlen -= len; } } } crFinishV; } /* * Handle the top-level SSH-2 protocol. */ static void ssh1_msg_debug(Ssh ssh, struct Packet *pktin) { char *msg; int msglen; ssh_pkt_getstring(pktin, &msg, &msglen); logeventf(ssh, "Remote debug message: %.*s", msglen, msg); } static void ssh1_msg_disconnect(Ssh ssh, struct Packet *pktin) { /* log reason code in disconnect message */ char *msg; int msglen; ssh_pkt_getstring(pktin, &msg, &msglen); bombout(("Server sent disconnect message:\n\"%.*s\"", msglen, msg)); } static void ssh_msg_ignore(Ssh ssh, struct Packet *pktin) { /* Do nothing, because we're ignoring it! Duhh. */ } static void ssh1_protocol_setup(Ssh ssh) { int i; /* * Most messages are handled by the coroutines. */ for (i = 0; i < 256; i++) ssh->packet_dispatch[i] = NULL; /* * These special message types we install handlers for. */ ssh->packet_dispatch[SSH1_MSG_DISCONNECT] = ssh1_msg_disconnect; ssh->packet_dispatch[SSH1_MSG_IGNORE] = ssh_msg_ignore; ssh->packet_dispatch[SSH1_MSG_DEBUG] = ssh1_msg_debug; } static void ssh1_protocol(Ssh ssh, void *vin, int inlen, struct Packet *pktin) { unsigned char *in=(unsigned char*)vin; if (ssh->state == SSH_STATE_CLOSED) return; if (pktin && ssh->packet_dispatch[pktin->type]) { ssh->packet_dispatch[pktin->type](ssh, pktin); return; } if (!ssh->protocol_initial_phase_done) { if (do_ssh1_login(ssh, in, inlen, pktin)) ssh->protocol_initial_phase_done = TRUE; else return; } do_ssh1_connection(ssh, in, inlen, pktin); } /* * Utility routine for decoding comma-separated strings in KEXINIT. */ static int in_commasep_string(char *needle, char *haystack, int haylen) { int needlen; if (!needle || !haystack) /* protect against null pointers */ return 0; needlen = strlen(needle); while (1) { /* * Is it at the start of the string? */ if (haylen >= needlen && /* haystack is long enough */ !memcmp(needle, haystack, needlen) && /* initial match */ (haylen == needlen || haystack[needlen] == ',') /* either , or EOS follows */ ) return 1; /* * If not, search for the next comma and resume after that. * If no comma found, terminate. */ while (haylen > 0 && *haystack != ',') haylen--, haystack++; if (haylen == 0) return 0; haylen--, haystack++; /* skip over comma itself */ } } /* * Similar routine for checking whether we have the first string in a list. */ static int first_in_commasep_string(char *needle, char *haystack, int haylen) { int needlen; if (!needle || !haystack) /* protect against null pointers */ return 0; needlen = strlen(needle); /* * Is it at the start of the string? */ if (haylen >= needlen && /* haystack is long enough */ !memcmp(needle, haystack, needlen) && /* initial match */ (haylen == needlen || haystack[needlen] == ',') /* either , or EOS follows */ ) return 1; return 0; } /* * SSH-2 key creation method. */ static void ssh2_mkkey(Ssh ssh, Bignum K, unsigned char *H, unsigned char *sessid, char chr, unsigned char *keyspace) { SHA_State s; /* First 20 bytes. */ SHA_Init(&s); if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY)) sha_mpint(&s, K); SHA_Bytes(&s, H, 20); SHA_Bytes(&s, &chr, 1); SHA_Bytes(&s, sessid, 20); SHA_Final(&s, keyspace); /* Next 20 bytes. */ SHA_Init(&s); if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY)) sha_mpint(&s, K); SHA_Bytes(&s, H, 20); SHA_Bytes(&s, keyspace, 20); SHA_Final(&s, keyspace + 20); } /* * Handle the SSH-2 transport layer. */ static int do_ssh2_transport(Ssh ssh, void *vin, int inlen, struct Packet *pktin) { unsigned char *in = (unsigned char *)vin; struct do_ssh2_transport_state { int nbits, pbits, warn_kex, warn_cscipher, warn_sccipher; Bignum p, g, e, f, K; int kex_init_value, kex_reply_value; const struct ssh_mac **maclist; int nmacs; const struct ssh2_cipher *cscipher_tobe; const struct ssh2_cipher *sccipher_tobe; const struct ssh_mac *csmac_tobe; const struct ssh_mac *scmac_tobe; const struct ssh_compress *cscomp_tobe; const struct ssh_compress *sccomp_tobe; char *hostkeydata, *sigdata, *keystr, *fingerprint; int hostkeylen, siglen; void *hkey; /* actual host key */ unsigned char exchange_hash[20]; int n_preferred_kex; const struct ssh_kex *preferred_kex[KEX_MAX]; int n_preferred_ciphers; const struct ssh2_ciphers *preferred_ciphers[CIPHER_MAX]; const struct ssh_compress *preferred_comp; int got_session_id, activated_authconn; struct Packet *pktout; int dlgret; int guessok; int ignorepkt; }; crState(do_ssh2_transport_state); crBegin(ssh->do_ssh2_transport_crstate); s->cscipher_tobe = s->sccipher_tobe = NULL; s->csmac_tobe = s->scmac_tobe = NULL; s->cscomp_tobe = s->sccomp_tobe = NULL; s->got_session_id = s->activated_authconn = FALSE; /* * Be prepared to work around the buggy MAC problem. */ if (ssh->remote_bugs & BUG_SSH2_HMAC) s->maclist = buggymacs, s->nmacs = lenof(buggymacs); else s->maclist = macs, s->nmacs = lenof(macs); begin_key_exchange: ssh->pkt_ctx &= ~SSH2_PKTCTX_KEX_MASK; { int i, j, commalist_started; /* * Set up the preferred key exchange. (NULL => warn below here) */ s->n_preferred_kex = 0; for (i = 0; i < KEX_MAX; i++) { switch (ssh->cfg.ssh_kexlist[i]) { case KEX_DHGEX: s->preferred_kex[s->n_preferred_kex++] = &ssh_diffiehellman_gex; break; case KEX_DHGROUP14: s->preferred_kex[s->n_preferred_kex++] = &ssh_diffiehellman_group14; break; case KEX_DHGROUP1: s->preferred_kex[s->n_preferred_kex++] = &ssh_diffiehellman_group1; break; case CIPHER_WARN: /* Flag for later. Don't bother if it's the last in * the list. */ if (i < KEX_MAX - 1) { s->preferred_kex[s->n_preferred_kex++] = NULL; } break; } } /* * Set up the preferred ciphers. (NULL => warn below here) */ s->n_preferred_ciphers = 0; for (i = 0; i < CIPHER_MAX; i++) { switch (ssh->cfg.ssh_cipherlist[i]) { case CIPHER_BLOWFISH: s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_blowfish; break; case CIPHER_DES: if (ssh->cfg.ssh2_des_cbc) { s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_des; } break; case CIPHER_3DES: s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_3des; break; case CIPHER_AES: s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_aes; break; case CIPHER_WARN: /* Flag for later. Don't bother if it's the last in * the list. */ if (i < CIPHER_MAX - 1) { s->preferred_ciphers[s->n_preferred_ciphers++] = NULL; } break; } } /* * Set up preferred compression. */ if (ssh->cfg.compression) s->preferred_comp = &ssh_zlib; else s->preferred_comp = &ssh_comp_none; /* * Enable queueing of outgoing auth- or connection-layer * packets while we are in the middle of a key exchange. */ ssh->queueing = TRUE; /* * Flag that KEX is in progress. */ ssh->kex_in_progress = TRUE; /* * Construct and send our key exchange packet. */ s->pktout = ssh2_pkt_init(SSH2_MSG_KEXINIT); for (i = 0; i < 16; i++) ssh2_pkt_addbyte(s->pktout, (unsigned char) random_byte()); /* List key exchange algorithms. */ ssh2_pkt_addstring_start(s->pktout); commalist_started = 0; for (i = 0; i < s->n_preferred_kex; i++) { const struct ssh_kex *k = s->preferred_kex[i]; if (!k) continue; /* warning flag */ if (commalist_started) ssh2_pkt_addstring_str(s->pktout, ","); ssh2_pkt_addstring_str(s->pktout, s->preferred_kex[i]->name); commalist_started = 1; } /* List server host key algorithms. */ ssh2_pkt_addstring_start(s->pktout); for (i = 0; i < lenof(hostkey_algs); i++) { ssh2_pkt_addstring_str(s->pktout, hostkey_algs[i]->name); if (i < lenof(hostkey_algs) - 1) ssh2_pkt_addstring_str(s->pktout, ","); } /* List client->server encryption algorithms. */ ssh2_pkt_addstring_start(s->pktout); commalist_started = 0; for (i = 0; i < s->n_preferred_ciphers; i++) { const struct ssh2_ciphers *c = s->preferred_ciphers[i]; if (!c) continue; /* warning flag */ for (j = 0; j < c->nciphers; j++) { if (commalist_started) ssh2_pkt_addstring_str(s->pktout, ","); ssh2_pkt_addstring_str(s->pktout, c->list[j]->name); commalist_started = 1; } } /* List server->client encryption algorithms. */ ssh2_pkt_addstring_start(s->pktout); commalist_started = 0; for (i = 0; i < s->n_preferred_ciphers; i++) { const struct ssh2_ciphers *c = s->preferred_ciphers[i]; if (!c) continue; /* warning flag */ for (j = 0; j < c->nciphers; j++) { if (commalist_started) ssh2_pkt_addstring_str(s->pktout, ","); ssh2_pkt_addstring_str(s->pktout, c->list[j]->name); commalist_started = 1; } } /* List client->server MAC algorithms. */ ssh2_pkt_addstring_start(s->pktout); for (i = 0; i < s->nmacs; i++) { ssh2_pkt_addstring_str(s->pktout, s->maclist[i]->name); if (i < s->nmacs - 1) ssh2_pkt_addstring_str(s->pktout, ","); } /* List server->client MAC algorithms. */ ssh2_pkt_addstring_start(s->pktout); for (i = 0; i < s->nmacs; i++) { ssh2_pkt_addstring_str(s->pktout, s->maclist[i]->name); if (i < s->nmacs - 1) ssh2_pkt_addstring_str(s->pktout, ","); } /* List client->server compression algorithms. */ ssh2_pkt_addstring_start(s->pktout); assert(lenof(compressions) > 1); ssh2_pkt_addstring_str(s->pktout, s->preferred_comp->name); for (i = 0; i < lenof(compressions); i++) { const struct ssh_compress *c = compressions[i]; if (c != s->preferred_comp) { ssh2_pkt_addstring_str(s->pktout, ","); ssh2_pkt_addstring_str(s->pktout, c->name); } } /* List server->client compression algorithms. */ ssh2_pkt_addstring_start(s->pktout); assert(lenof(compressions) > 1); ssh2_pkt_addstring_str(s->pktout, s->preferred_comp->name); for (i = 0; i < lenof(compressions); i++) { const struct ssh_compress *c = compressions[i]; if (c != s->preferred_comp) { ssh2_pkt_addstring_str(s->pktout, ","); ssh2_pkt_addstring_str(s->pktout, c->name); } } /* List client->server languages. Empty list. */ ssh2_pkt_addstring_start(s->pktout); /* List server->client languages. Empty list. */ ssh2_pkt_addstring_start(s->pktout); /* First KEX packet does _not_ follow, because we're not that brave. */ ssh2_pkt_addbool(s->pktout, FALSE); /* Reserved. */ ssh2_pkt_adduint32(s->pktout, 0); } ssh->exhash = ssh->exhashbase; sha_string(&ssh->exhash, s->pktout->data + 5, s->pktout->length - 5); ssh2_pkt_send_noqueue(ssh, s->pktout); if (!pktin) crWaitUntil(pktin); if (pktin->length > 5) sha_string(&ssh->exhash, pktin->data + 5, pktin->length - 5); /* * Now examine the other side's KEXINIT to see what we're up * to. */ { char *str, *preferred; int i, j, len; if (pktin->type != SSH2_MSG_KEXINIT) { bombout(("expected key exchange packet from server")); crStop(0); } ssh->kex = NULL; ssh->hostkey = NULL; s->cscipher_tobe = NULL; s->sccipher_tobe = NULL; s->csmac_tobe = NULL; s->scmac_tobe = NULL; s->cscomp_tobe = NULL; s->sccomp_tobe = NULL; s->warn_kex = s->warn_cscipher = s->warn_sccipher = FALSE; pktin->savedpos += 16; /* skip garbage cookie */ ssh_pkt_getstring(pktin, &str, &len); /* key exchange algorithms */ preferred = NULL; for (i = 0; i < s->n_preferred_kex; i++) { const struct ssh_kex *k = s->preferred_kex[i]; if (!k) { s->warn_kex = TRUE; } else { if (!preferred) preferred = k->name; if (in_commasep_string(k->name, str, len)) ssh->kex = k; } if (ssh->kex) break; } if (!ssh->kex) { bombout(("Couldn't agree a key exchange algorithm (available: %s)", str ? str : "(null)")); crStop(0); } /* * Note that the server's guess is considered wrong if it doesn't match * the first algorithm in our list, even if it's still the algorithm * we end up using. */ s->guessok = first_in_commasep_string(preferred, str, len); ssh_pkt_getstring(pktin, &str, &len); /* host key algorithms */ for (i = 0; i < lenof(hostkey_algs); i++) { if (in_commasep_string(hostkey_algs[i]->name, str, len)) { ssh->hostkey = hostkey_algs[i]; break; } } s->guessok = s->guessok && first_in_commasep_string(hostkey_algs[0]->name, str, len); ssh_pkt_getstring(pktin, &str, &len); /* client->server cipher */ for (i = 0; i < s->n_preferred_ciphers; i++) { const struct ssh2_ciphers *c = s->preferred_ciphers[i]; if (!c) { s->warn_cscipher = TRUE; } else { for (j = 0; j < c->nciphers; j++) { if (in_commasep_string(c->list[j]->name, str, len)) { s->cscipher_tobe = c->list[j]; break; } } } if (s->cscipher_tobe) break; } if (!s->cscipher_tobe) { bombout(("Couldn't agree a client-to-server cipher (available: %s)", str ? str : "(null)")); crStop(0); } ssh_pkt_getstring(pktin, &str, &len); /* server->client cipher */ for (i = 0; i < s->n_preferred_ciphers; i++) { const struct ssh2_ciphers *c = s->preferred_ciphers[i]; if (!c) { s->warn_sccipher = TRUE; } else { for (j = 0; j < c->nciphers; j++) { if (in_commasep_string(c->list[j]->name, str, len)) { s->sccipher_tobe = c->list[j]; break; } } } if (s->sccipher_tobe) break; } if (!s->sccipher_tobe) { bombout(("Couldn't agree a server-to-client cipher (available: %s)", str ? str : "(null)")); crStop(0); } ssh_pkt_getstring(pktin, &str, &len); /* client->server mac */ for (i = 0; i < s->nmacs; i++) { if (in_commasep_string(s->maclist[i]->name, str, len)) { s->csmac_tobe = s->maclist[i]; break; } } ssh_pkt_getstring(pktin, &str, &len); /* server->client mac */ for (i = 0; i < s->nmacs; i++) { if (in_commasep_string(s->maclist[i]->name, str, len)) { s->scmac_tobe = s->maclist[i]; break; } } ssh_pkt_getstring(pktin, &str, &len); /* client->server compression */ for (i = 0; i < lenof(compressions) + 1; i++) { const struct ssh_compress *c = i == 0 ? s->preferred_comp : compressions[i - 1]; if (in_commasep_string(c->name, str, len)) { s->cscomp_tobe = c; break; } } ssh_pkt_getstring(pktin, &str, &len); /* server->client compression */ for (i = 0; i < lenof(compressions) + 1; i++) { const struct ssh_compress *c = i == 0 ? s->preferred_comp : compressions[i - 1]; if (in_commasep_string(c->name, str, len)) { s->sccomp_tobe = c; break; } } ssh_pkt_getstring(pktin, &str, &len); /* client->server language */ ssh_pkt_getstring(pktin, &str, &len); /* server->client language */ s->ignorepkt = ssh2_pkt_getbool(pktin) && !s->guessok; if (s->warn_kex) { ssh_set_frozen(ssh, 1); s->dlgret = askalg(ssh->frontend, "key-exchange algorithm", ssh->kex->name, ssh_dialog_callback, ssh); if (s->dlgret < 0) { do { crReturn(0); if (pktin) { bombout(("Unexpected data from server while" " waiting for user response")); crStop(0); } } while (pktin || inlen > 0); s->dlgret = ssh->user_response; } ssh_set_frozen(ssh, 0); if (s->dlgret == 0) { ssh->close_expected = TRUE; ssh_closing((Plug)ssh, NULL, 0, 0); crStop(0); } } if (s->warn_cscipher) { ssh_set_frozen(ssh, 1); s->dlgret = askalg(ssh->frontend, "client-to-server cipher", s->cscipher_tobe->name, ssh_dialog_callback, ssh); if (s->dlgret < 0) { do { crReturn(0); if (pktin) { bombout(("Unexpected data from server while" " waiting for user response")); crStop(0); } } while (pktin || inlen > 0); s->dlgret = ssh->user_response; } ssh_set_frozen(ssh, 0); if (s->dlgret == 0) { ssh->close_expected = TRUE; ssh_closing((Plug)ssh, NULL, 0, 0); crStop(0); } } if (s->warn_sccipher) { ssh_set_frozen(ssh, 1); s->dlgret = askalg(ssh->frontend, "server-to-client cipher", s->sccipher_tobe->name, ssh_dialog_callback, ssh); if (s->dlgret < 0) { do { crReturn(0); if (pktin) { bombout(("Unexpected data from server while" " waiting for user response")); crStop(0); } } while (pktin || inlen > 0); s->dlgret = ssh->user_response; } ssh_set_frozen(ssh, 0); if (s->dlgret == 0) { ssh->close_expected = TRUE; ssh_closing((Plug)ssh, NULL, 0, 0); crStop(0); } } if (s->ignorepkt) /* first_kex_packet_follows */ crWaitUntil(pktin); /* Ignore packet */ } /* * Work out the number of bits of key we will need from the key * exchange. We start with the maximum key length of either * cipher... */ { int csbits, scbits; csbits = s->cscipher_tobe->keylen; scbits = s->sccipher_tobe->keylen; s->nbits = (csbits > scbits ? csbits : scbits); } /* The keys only have 160-bit entropy, since they're based on * a SHA-1 hash. So cap the key size at 160 bits. */ if (s->nbits > 160) s->nbits = 160; /* * If we're doing Diffie-Hellman group exchange, start by * requesting a group. */ if (!ssh->kex->pdata) { logevent("Doing Diffie-Hellman group exchange"); ssh->pkt_ctx |= SSH2_PKTCTX_DHGEX; /* * Work out how big a DH group we will need to allow that * much data. */ s->pbits = 512 << ((s->nbits - 1) / 64); s->pktout = ssh2_pkt_init(SSH2_MSG_KEX_DH_GEX_REQUEST); ssh2_pkt_adduint32(s->pktout, s->pbits); ssh2_pkt_send_noqueue(ssh, s->pktout); crWaitUntil(pktin); if (pktin->type != SSH2_MSG_KEX_DH_GEX_GROUP) { bombout(("expected key exchange group packet from server")); crStop(0); } s->p = ssh2_pkt_getmp(pktin); s->g = ssh2_pkt_getmp(pktin); if (!s->p || !s->g) { bombout(("unable to read mp-ints from incoming group packet")); crStop(0); } ssh->kex_ctx = dh_setup_gex(s->p, s->g); s->kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT; s->kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY; } else { ssh->pkt_ctx |= SSH2_PKTCTX_DHGROUP; ssh->kex_ctx = dh_setup_group(ssh->kex); s->kex_init_value = SSH2_MSG_KEXDH_INIT; s->kex_reply_value = SSH2_MSG_KEXDH_REPLY; logeventf(ssh, "Using Diffie-Hellman with standard group \"%s\"", ssh->kex->groupname); } logevent("Doing Diffie-Hellman key exchange"); /* * Now generate and send e for Diffie-Hellman. */ set_busy_status(ssh->frontend, BUSY_CPU); /* this can take a while */ s->e = dh_create_e(ssh->kex_ctx, s->nbits * 2); s->pktout = ssh2_pkt_init(s->kex_init_value); ssh2_pkt_addmp(s->pktout, s->e); ssh2_pkt_send_noqueue(ssh, s->pktout); set_busy_status(ssh->frontend, BUSY_WAITING); /* wait for server */ crWaitUntil(pktin); if (pktin->type != s->kex_reply_value) { bombout(("expected key exchange reply packet from server")); crStop(0); } set_busy_status(ssh->frontend, BUSY_CPU); /* cogitate */ ssh_pkt_getstring(pktin, &s->hostkeydata, &s->hostkeylen); s->f = ssh2_pkt_getmp(pktin); if (!s->f) { bombout(("unable to parse key exchange reply packet")); crStop(0); } ssh_pkt_getstring(pktin, &s->sigdata, &s->siglen); s->K = dh_find_K(ssh->kex_ctx, s->f); /* We assume everything from now on will be quick, and it might * involve user interaction. */ set_busy_status(ssh->frontend, BUSY_NOT); sha_string(&ssh->exhash, s->hostkeydata, s->hostkeylen); if (ssh->kex == &ssh_diffiehellman_gex) { sha_uint32(&ssh->exhash, s->pbits); sha_mpint(&ssh->exhash, s->p); sha_mpint(&ssh->exhash, s->g); } sha_mpint(&ssh->exhash, s->e); sha_mpint(&ssh->exhash, s->f); sha_mpint(&ssh->exhash, s->K); SHA_Final(&ssh->exhash, s->exchange_hash); dh_cleanup(ssh->kex_ctx); ssh->kex_ctx = NULL; #if 0 debug(("Exchange hash is:\n")); dmemdump(s->exchange_hash, 20); #endif s->hkey = ssh->hostkey->newkey(s->hostkeydata, s->hostkeylen); if (!s->hkey || !ssh->hostkey->verifysig(s->hkey, s->sigdata, s->siglen, (char *)s->exchange_hash, 20)) { bombout(("Server's host key did not match the signature supplied")); crStop(0); } /* * Authenticate remote host: verify host key. (We've already * checked the signature of the exchange hash.) */ s->keystr = ssh->hostkey->fmtkey(s->hkey); s->fingerprint = ssh->hostkey->fingerprint(s->hkey); ssh_set_frozen(ssh, 1); s->dlgret = verify_ssh_host_key(ssh->frontend, ssh->savedhost, ssh->savedport, ssh->hostkey->keytype, s->keystr, s->fingerprint, ssh_dialog_callback, ssh); if (s->dlgret < 0) { do { crReturn(0); if (pktin) { bombout(("Unexpected data from server while waiting" " for user host key response")); crStop(0); } } while (pktin || inlen > 0); s->dlgret = ssh->user_response; } ssh_set_frozen(ssh, 0); if (s->dlgret == 0) { ssh->close_expected = TRUE; ssh_closing((Plug)ssh, NULL, 0, 0); crStop(0); } if (!s->got_session_id) { /* don't bother logging this in rekeys */ logevent("Host key fingerprint is:"); logevent(s->fingerprint); } sfree(s->fingerprint); sfree(s->keystr); ssh->hostkey->freekey(s->hkey); /* * The exchange hash from the very first key exchange is also * the session id, used in session key construction and * authentication. */ if (!s->got_session_id) { memcpy(ssh->v2_session_id, s->exchange_hash, sizeof(s->exchange_hash)); s->got_session_id = TRUE; } /* * Send SSH2_MSG_NEWKEYS. */ s->pktout = ssh2_pkt_init(SSH2_MSG_NEWKEYS); ssh2_pkt_send_noqueue(ssh, s->pktout); ssh->outgoing_data_size = 0; /* start counting from here */ /* * We've sent client NEWKEYS, so create and initialise * client-to-server session keys. */ if (ssh->cs_cipher_ctx) ssh->cscipher->free_context(ssh->cs_cipher_ctx); ssh->cscipher = s->cscipher_tobe; ssh->cs_cipher_ctx = ssh->cscipher->make_context(); if (ssh->cs_mac_ctx) ssh->csmac->free_context(ssh->cs_mac_ctx); ssh->csmac = s->csmac_tobe; ssh->cs_mac_ctx = ssh->csmac->make_context(); if (ssh->cs_comp_ctx) ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx); ssh->cscomp = s->cscomp_tobe; ssh->cs_comp_ctx = ssh->cscomp->compress_init(); /* * Set IVs on client-to-server keys. Here we use the exchange * hash from the _first_ key exchange. */ { unsigned char keyspace[40]; ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'C',keyspace); ssh->cscipher->setkey(ssh->cs_cipher_ctx, keyspace); ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'A',keyspace); ssh->cscipher->setiv(ssh->cs_cipher_ctx, keyspace); ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'E',keyspace); ssh->csmac->setkey(ssh->cs_mac_ctx, keyspace); } logeventf(ssh, "Initialised %.200s client->server encryption", ssh->cscipher->text_name); logeventf(ssh, "Initialised %.200s client->server MAC algorithm", ssh->csmac->text_name); if (ssh->cscomp->text_name) logeventf(ssh, "Initialised %s compression", ssh->cscomp->text_name); /* * Now our end of the key exchange is complete, we can send all * our queued higher-layer packets. */ ssh->queueing = FALSE; ssh2_pkt_queuesend(ssh); /* * Expect SSH2_MSG_NEWKEYS from server. */ crWaitUntil(pktin); if (pktin->type != SSH2_MSG_NEWKEYS) { bombout(("expected new-keys packet from server")); crStop(0); } ssh->incoming_data_size = 0; /* start counting from here */ /* * We've seen server NEWKEYS, so create and initialise * server-to-client session keys. */ if (ssh->sc_cipher_ctx) ssh->sccipher->free_context(ssh->sc_cipher_ctx); ssh->sccipher = s->sccipher_tobe; ssh->sc_cipher_ctx = ssh->sccipher->make_context(); if (ssh->sc_mac_ctx) ssh->scmac->free_context(ssh->sc_mac_ctx); ssh->scmac = s->scmac_tobe; ssh->sc_mac_ctx = ssh->scmac->make_context(); if (ssh->sc_comp_ctx) ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx); ssh->sccomp = s->sccomp_tobe; ssh->sc_comp_ctx = ssh->sccomp->decompress_init(); /* * Set IVs on server-to-client keys. Here we use the exchange * hash from the _first_ key exchange. */ { unsigned char keyspace[40]; ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'D',keyspace); ssh->sccipher->setkey(ssh->sc_cipher_ctx, keyspace); ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'B',keyspace); ssh->sccipher->setiv(ssh->sc_cipher_ctx, keyspace); ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'F',keyspace); ssh->scmac->setkey(ssh->sc_mac_ctx, keyspace); } logeventf(ssh, "Initialised %.200s server->client encryption", ssh->sccipher->text_name); logeventf(ssh, "Initialised %.200s server->client MAC algorithm", ssh->scmac->text_name); if (ssh->sccomp->text_name) logeventf(ssh, "Initialised %s decompression", ssh->sccomp->text_name); /* * Free key exchange data. */ freebn(s->f); freebn(s->K); if (ssh->kex == &ssh_diffiehellman_gex) { freebn(s->g); freebn(s->p); } /* * Key exchange is over. Loop straight back round if we have a * deferred rekey reason. */ if (ssh->deferred_rekey_reason) { logevent(ssh->deferred_rekey_reason); pktin = NULL; ssh->deferred_rekey_reason = NULL; goto begin_key_exchange; } /* * Otherwise, schedule a timer for our next rekey. */ ssh->kex_in_progress = FALSE; ssh->last_rekey = GETTICKCOUNT(); if (ssh->cfg.ssh_rekey_time != 0) ssh->next_rekey = schedule_timer(ssh->cfg.ssh_rekey_time*60*TICKSPERSEC, ssh2_timer, ssh); /* * If this is the first key exchange phase, we must pass the * SSH2_MSG_NEWKEYS packet to the next layer, not because it * wants to see it but because it will need time to initialise * itself before it sees an actual packet. In subsequent key * exchange phases, we don't pass SSH2_MSG_NEWKEYS on, because * it would only confuse the layer above. */ if (s->activated_authconn) { crReturn(1); } s->activated_authconn = TRUE; /* * Now we're encrypting. Begin returning 1 to the protocol main * function so that other things can run on top of the * transport. If we ever see a KEXINIT, we must go back to the * start. * * We _also_ go back to the start if we see pktin==NULL and * inlen==-1, because this is a special signal meaning * `initiate client-driven rekey', and `in' contains a message * giving the reason for the rekey. */ while (!((pktin && pktin->type == SSH2_MSG_KEXINIT) || (!pktin && inlen == -1))) { wait_for_rekey: crReturn(1); } if (pktin) { logevent("Server initiated key re-exchange"); } else { /* * Special case: if the server bug is set that doesn't * allow rekeying, we give a different log message and * continue waiting. (If such a server _initiates_ a rekey, * we process it anyway!) */ if ((ssh->remote_bugs & BUG_SSH2_REKEY)) { logeventf(ssh, "Server bug prevents key re-exchange (%s)", (char *)in); /* Reset the counters, so that at least this message doesn't * hit the event log _too_ often. */ ssh->outgoing_data_size = 0; ssh->incoming_data_size = 0; if (ssh->cfg.ssh_rekey_time != 0) { ssh->next_rekey = schedule_timer(ssh->cfg.ssh_rekey_time*60*TICKSPERSEC, ssh2_timer, ssh); } goto wait_for_rekey; /* this is utterly horrid */ } else { logeventf(ssh, "Initiating key re-exchange (%s)", (char *)in); } } goto begin_key_exchange; crFinish(1); } /* * Add data to an SSH-2 channel output buffer. */ static void ssh2_add_channel_data(struct ssh_channel *c, char *buf, int len) { bufchain_add(&c->v.v2.outbuffer, buf, len); } /* * Attempt to send data on an SSH-2 channel. */ static int ssh2_try_send(struct ssh_channel *c) { Ssh ssh = c->ssh; struct Packet *pktout; while (c->v.v2.remwindow > 0 && bufchain_size(&c->v.v2.outbuffer) > 0) { int len; void *data; bufchain_prefix(&c->v.v2.outbuffer, &data, &len); if ((unsigned)len > c->v.v2.remwindow) len = c->v.v2.remwindow; if ((unsigned)len > c->v.v2.remmaxpkt) len = c->v.v2.remmaxpkt; pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_DATA); ssh2_pkt_adduint32(pktout, c->remoteid); dont_log_data(ssh, pktout, PKTLOG_OMIT); ssh2_pkt_addstring_start(pktout); ssh2_pkt_addstring_data(pktout, data, len); end_log_omission(ssh, pktout); ssh2_pkt_send(ssh, pktout); bufchain_consume(&c->v.v2.outbuffer, len); c->v.v2.remwindow -= len; } /* * After having sent as much data as we can, return the amount * still buffered. */ return bufchain_size(&c->v.v2.outbuffer); } static void ssh2_try_send_and_unthrottle(struct ssh_channel *c) { int bufsize; if (c->closes) return; /* don't send on closing channels */ bufsize = ssh2_try_send(c); if (bufsize == 0) { switch (c->type) { case CHAN_MAINSESSION: /* stdin need not receive an unthrottle * notification since it will be polled */ break; case CHAN_X11: x11_unthrottle(c->u.x11.s); break; case CHAN_AGENT: /* agent sockets are request/response and need no * buffer management */ break; case CHAN_SOCKDATA: pfd_unthrottle(c->u.pfd.s); break; } } } /* * Potentially enlarge the window on an SSH-2 channel. */ static void ssh2_set_window(struct ssh_channel *c, unsigned newwin) { Ssh ssh = c->ssh; /* * Never send WINDOW_ADJUST for a channel that the remote side * already thinks it's closed; there's no point, since it won't * be sending any more data anyway. */ if (c->closes != 0) return; /* * Only send a WINDOW_ADJUST if there's significantly more window * available than the other end thinks there is. This saves us * sending a WINDOW_ADJUST for every character in a shell session. * * "Significant" is arbitrarily defined as half the window size. */ if (newwin > c->v.v2.locwindow * 2) { struct Packet *pktout; pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_WINDOW_ADJUST); ssh2_pkt_adduint32(pktout, c->remoteid); ssh2_pkt_adduint32(pktout, newwin - c->v.v2.locwindow); ssh2_pkt_send(ssh, pktout); c->v.v2.locwindow = newwin; } } static void ssh2_msg_channel_window_adjust(Ssh ssh, struct Packet *pktin) { unsigned i = ssh_pkt_getuint32(pktin); struct ssh_channel *c; c = find234(ssh->channels, &i, ssh_channelfind); if (c && !c->closes) { c->v.v2.remwindow += ssh_pkt_getuint32(pktin); ssh2_try_send_and_unthrottle(c); } } static void ssh2_msg_channel_data(Ssh ssh, struct Packet *pktin) { char *data; int length; unsigned i = ssh_pkt_getuint32(pktin); struct ssh_channel *c; c = find234(ssh->channels, &i, ssh_channelfind); if (!c) return; /* nonexistent channel */ if (pktin->type == SSH2_MSG_CHANNEL_EXTENDED_DATA && ssh_pkt_getuint32(pktin) != SSH2_EXTENDED_DATA_STDERR) return; /* extended but not stderr */ ssh_pkt_getstring(pktin, &data, &length); if (data) { int bufsize = 0; c->v.v2.locwindow -= length; switch (c->type) { case CHAN_MAINSESSION: bufsize = from_backend(ssh->frontend, pktin->type == SSH2_MSG_CHANNEL_EXTENDED_DATA, data, length); break; case CHAN_X11: bufsize = x11_send(c->u.x11.s, data, length); break; case CHAN_SOCKDATA: bufsize = pfd_send(c->u.pfd.s, data, length); break; case CHAN_AGENT: while (length > 0) { if (c->u.a.lensofar < 4) { unsigned int l = min(4 - c->u.a.lensofar, length); memcpy(c->u.a.msglen + c->u.a.lensofar, data, l); data += l; length -= l; c->u.a.lensofar += l; } if (c->u.a.lensofar == 4) { c->u.a.totallen = 4 + GET_32BIT(c->u.a.msglen); c->u.a.message = snewn(c->u.a.totallen, unsigned char); memcpy(c->u.a.message, c->u.a.msglen, 4); } if (c->u.a.lensofar >= 4 && length > 0) { unsigned int l = min(c->u.a.totallen - c->u.a.lensofar, length); memcpy(c->u.a.message + c->u.a.lensofar, data, l); data += l; length -= l; c->u.a.lensofar += l; } if (c->u.a.lensofar == c->u.a.totallen) { void *reply; int replylen; if (agent_query(c->u.a.message, c->u.a.totallen, &reply, &replylen, ssh_agentf_callback, c)) ssh_agentf_callback(c, reply, replylen); sfree(c->u.a.message); c->u.a.lensofar = 0; } } bufsize = 0; break; } /* * If we are not buffering too much data, * enlarge the window again at the remote side. */ if (bufsize < OUR_V2_WINSIZE) ssh2_set_window(c, OUR_V2_WINSIZE - bufsize); } } static void ssh2_msg_channel_eof(Ssh ssh, struct Packet *pktin) { unsigned i = ssh_pkt_getuint32(pktin); struct ssh_channel *c; c = find234(ssh->channels, &i, ssh_channelfind); if (!c) return; /* nonexistent channel */ if (c->type == CHAN_X11) { /* * Remote EOF on an X11 channel means we should * wrap up and close the channel ourselves. */ x11_close(c->u.x11.s); sshfwd_close(c); } else if (c->type == CHAN_AGENT) { sshfwd_close(c); } else if (c->type == CHAN_SOCKDATA) { pfd_close(c->u.pfd.s); sshfwd_close(c); } } static void ssh2_msg_channel_close(Ssh ssh, struct Packet *pktin) { unsigned i = ssh_pkt_getuint32(pktin); struct ssh_channel *c; struct Packet *pktout; c = find234(ssh->channels, &i, ssh_channelfind); if (!c || c->halfopen) { bombout(("Received CHANNEL_CLOSE for %s channel %d\n", c ? "half-open" : "nonexistent", i)); return; } /* Do pre-close processing on the channel. */ switch (c->type) { case CHAN_MAINSESSION: ssh->mainchan = NULL; update_specials_menu(ssh->frontend); break; case CHAN_X11: if (c->u.x11.s != NULL) x11_close(c->u.x11.s); sshfwd_close(c); break; case CHAN_AGENT: sshfwd_close(c); break; case CHAN_SOCKDATA: if (c->u.pfd.s != NULL) pfd_close(c->u.pfd.s); sshfwd_close(c); break; } if (c->closes == 0) { pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE); ssh2_pkt_adduint32(pktout, c->remoteid); ssh2_pkt_send(ssh, pktout); } del234(ssh->channels, c); bufchain_clear(&c->v.v2.outbuffer); sfree(c); /* * See if that was the last channel left open. * (This is only our termination condition if we're * not running in -N mode.) */ if (!ssh->cfg.ssh_no_shell && count234(ssh->channels) == 0) { logevent("All channels closed. Disconnecting"); #if 0 /* * We used to send SSH_MSG_DISCONNECT here, * because I'd believed that _every_ conforming * SSH-2 connection had to end with a disconnect * being sent by at least one side; apparently * I was wrong and it's perfectly OK to * unceremoniously slam the connection shut * when you're done, and indeed OpenSSH feels * this is more polite than sending a * DISCONNECT. So now we don't. */ s->pktout = ssh2_pkt_init(SSH2_MSG_DISCONNECT); ssh2_pkt_adduint32(s->pktout, SSH2_DISCONNECT_BY_APPLICATION); ssh2_pkt_addstring(s->pktout, "All open channels closed"); ssh2_pkt_addstring(s->pktout, "en"); /* language tag */ ssh2_pkt_send_noqueue(ssh, s->pktout); #endif ssh->close_expected = TRUE; ssh_closing((Plug)ssh, NULL, 0, 0); } } static void ssh2_msg_channel_open_confirmation(Ssh ssh, struct Packet *pktin) { unsigned i = ssh_pkt_getuint32(pktin); struct ssh_channel *c; struct Packet *pktout; c = find234(ssh->channels, &i, ssh_channelfind); if (!c) return; /* nonexistent channel */ if (c->type != CHAN_SOCKDATA_DORMANT) return; /* dunno why they're confirming this */ c->remoteid = ssh_pkt_getuint32(pktin); c->halfopen = FALSE; c->type = CHAN_SOCKDATA; c->v.v2.remwindow = ssh_pkt_getuint32(pktin); c->v.v2.remmaxpkt = ssh_pkt_getuint32(pktin); if (c->u.pfd.s) pfd_confirm(c->u.pfd.s); if (c->closes) { /* * We have a pending close on this channel, * which we decided on before the server acked * the channel open. So now we know the * remoteid, we can close it again. */ pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE); ssh2_pkt_adduint32(pktout, c->remoteid); ssh2_pkt_send(ssh, pktout); } } static void ssh2_msg_channel_open_failure(Ssh ssh, struct Packet *pktin) { static const char *const reasons[] = { "", "Administratively prohibited", "Connect failed", "Unknown channel type", "Resource shortage", }; unsigned i = ssh_pkt_getuint32(pktin); unsigned reason_code; char *reason_string; int reason_length; struct ssh_channel *c; c = find234(ssh->channels, &i, ssh_channelfind); if (!c) return; /* nonexistent channel */ if (c->type != CHAN_SOCKDATA_DORMANT) return; /* dunno why they're failing this */ reason_code = ssh_pkt_getuint32(pktin); if (reason_code >= lenof(reasons)) reason_code = 0; /* ensure reasons[reason_code] in range */ ssh_pkt_getstring(pktin, &reason_string, &reason_length); logeventf(ssh, "Forwarded connection refused by server: %s [%.*s]", reasons[reason_code], reason_length, reason_string); pfd_close(c->u.pfd.s); del234(ssh->channels, c); sfree(c); } static void ssh2_msg_channel_request(Ssh ssh, struct Packet *pktin) { unsigned localid; char *type; int typelen, want_reply; int reply = SSH2_MSG_CHANNEL_FAILURE; /* default */ struct ssh_channel *c; struct Packet *pktout; localid = ssh_pkt_getuint32(pktin); ssh_pkt_getstring(pktin, &type, &typelen); want_reply = ssh2_pkt_getbool(pktin); /* * First, check that the channel exists. Otherwise, * we can instantly disconnect with a rude message. */ c = find234(ssh->channels, &localid, ssh_channelfind); if (!c) { char buf[80]; sprintf(buf, "Received channel request for nonexistent" " channel %d", localid); logevent(buf); pktout = ssh2_pkt_init(SSH2_MSG_DISCONNECT); ssh2_pkt_adduint32(pktout, SSH2_DISCONNECT_BY_APPLICATION); ssh2_pkt_addstring(pktout, buf); ssh2_pkt_addstring(pktout, "en"); /* language tag */ ssh2_pkt_send_noqueue(ssh, pktout); connection_fatal(ssh->frontend, "%s", buf); ssh->close_expected = TRUE; ssh_closing((Plug)ssh, NULL, 0, 0); return; } /* * Having got the channel number, we now look at * the request type string to see if it's something * we recognise. */ if (c == ssh->mainchan) { /* * We recognise "exit-status" and "exit-signal" on * the primary channel. */ if (typelen == 11 && !memcmp(type, "exit-status", 11)) { ssh->exitcode = ssh_pkt_getuint32(pktin); logeventf(ssh, "Server sent command exit status %d", ssh->exitcode); reply = SSH2_MSG_CHANNEL_SUCCESS; } else if (typelen == 11 && !memcmp(type, "exit-signal", 11)) { int is_plausible = TRUE, is_int = FALSE; char *fmt_sig = "", *fmt_msg = ""; char *msg; int msglen = 0, core = FALSE; /* ICK: older versions of OpenSSH (e.g. 3.4p1) * provide an `int' for the signal, despite its * having been a `string' in the drafts since at * least 2001. (Fixed in session.c 1.147.) Try to * infer which we can safely parse it as. */ { unsigned char *p = pktin->body + pktin->savedpos; long len = pktin->length - pktin->savedpos; unsigned long num = GET_32BIT(p); /* what is it? */ /* If it's 0, it hardly matters; assume string */ if (num == 0) { is_int = FALSE; } else { int maybe_int = FALSE, maybe_str = FALSE; #define CHECK_HYPOTHESIS(offset, result) \ do { \ long q = offset; \ if (q >= 0 && q+4 <= len) { \ q = q + 4 + GET_32BIT(p+q); \ if (q >= 0 && q+4 <= len && \ ((q = q + 4 + GET_32BIT(p+q))!= 0) && q == len) \ result = TRUE; \ } \ } while(0) CHECK_HYPOTHESIS(4+1, maybe_int); CHECK_HYPOTHESIS(4+num+1, maybe_str); #undef CHECK_HYPOTHESIS if (maybe_int && !maybe_str) is_int = TRUE; else if (!maybe_int && maybe_str) is_int = FALSE; else /* Crikey. Either or neither. Panic. */ is_plausible = FALSE; } } if (is_plausible) { if (is_int) { /* Old non-standard OpenSSH. */ int signum = ssh_pkt_getuint32(pktin); fmt_sig = dupprintf(" %d", signum); } else { /* As per the drafts. */ char *sig; int siglen; ssh_pkt_getstring(pktin, &sig, &siglen); /* Signal name isn't supposed to be blank, but * let's cope gracefully if it is. */ if (siglen) { fmt_sig = dupprintf(" \"%.*s\"", siglen, sig); } } core = ssh2_pkt_getbool(pktin); ssh_pkt_getstring(pktin, &msg, &msglen); if (msglen) { fmt_msg = dupprintf(" (\"%.*s\")", msglen, msg); } /* ignore lang tag */ } /* else don't attempt to parse */ logeventf(ssh, "Server exited on signal%s%s%s", fmt_sig, core ? " (core dumped)" : "", fmt_msg); if (*fmt_sig) sfree(fmt_sig); if (*fmt_msg) sfree(fmt_msg); reply = SSH2_MSG_CHANNEL_SUCCESS; } } else { /* * This is a channel request we don't know * about, so we now either ignore the request * or respond with CHANNEL_FAILURE, depending * on want_reply. */ reply = SSH2_MSG_CHANNEL_FAILURE; } if (want_reply) { pktout = ssh2_pkt_init(reply); ssh2_pkt_adduint32(pktout, c->remoteid); ssh2_pkt_send(ssh, pktout); } } static void ssh2_msg_global_request(Ssh ssh, struct Packet *pktin) { char *type; int typelen, want_reply; struct Packet *pktout; ssh_pkt_getstring(pktin, &type, &typelen); want_reply = ssh2_pkt_getbool(pktin); /* * We currently don't support any global requests * at all, so we either ignore the request or * respond with REQUEST_FAILURE, depending on * want_reply. */ if (want_reply) { pktout = ssh2_pkt_init(SSH2_MSG_REQUEST_FAILURE); ssh2_pkt_send(ssh, pktout); } } static void ssh2_msg_channel_open(Ssh ssh, struct Packet *pktin) { char *type; int typelen; char *peeraddr; int peeraddrlen; int peerport; char *error = NULL; struct ssh_channel *c; unsigned remid, winsize, pktsize; struct Packet *pktout; ssh_pkt_getstring(pktin, &type, &typelen); c = snew(struct ssh_channel); c->ssh = ssh; remid = ssh_pkt_getuint32(pktin); winsize = ssh_pkt_getuint32(pktin); pktsize = ssh_pkt_getuint32(pktin); if (typelen == 3 && !memcmp(type, "x11", 3)) { char *addrstr; ssh_pkt_getstring(pktin, &peeraddr, &peeraddrlen); addrstr = snewn(peeraddrlen+1, char); memcpy(addrstr, peeraddr, peeraddrlen); addrstr[peeraddrlen] = '\0'; peerport = ssh_pkt_getuint32(pktin); logeventf(ssh, "Received X11 connect request from %s:%d", addrstr, peerport); if (!ssh->X11_fwd_enabled) error = "X11 forwarding is not enabled"; else if (x11_init(&c->u.x11.s, ssh->cfg.x11_display, c, ssh->x11auth, addrstr, peerport, &ssh->cfg) != NULL) { error = "Unable to open an X11 connection"; } else { logevent("Opening X11 forward connection succeeded"); c->type = CHAN_X11; } sfree(addrstr); } else if (typelen == 15 && !memcmp(type, "forwarded-tcpip", 15)) { struct ssh_rportfwd pf, *realpf; char *dummy; int dummylen; ssh_pkt_getstring(pktin, &dummy, &dummylen);/* skip address */ pf.sport = ssh_pkt_getuint32(pktin); ssh_pkt_getstring(pktin, &peeraddr, &peeraddrlen); peerport = ssh_pkt_getuint32(pktin); realpf = find234(ssh->rportfwds, &pf, NULL); logeventf(ssh, "Received remote port %d open request " "from %s:%d", pf.sport, peeraddr, peerport); if (realpf == NULL) { error = "Remote port is not recognised"; } else { const char *e = pfd_newconnect(&c->u.pfd.s, realpf->dhost, realpf->dport, c, &ssh->cfg, realpf->pfrec->addressfamily); logeventf(ssh, "Attempting to forward remote port to " "%s:%d", realpf->dhost, realpf->dport); if (e != NULL) { logeventf(ssh, "Port open failed: %s", e); error = "Port open failed"; } else { logevent("Forwarded port opened successfully"); c->type = CHAN_SOCKDATA; } } } else if (typelen == 22 && !memcmp(type, "auth-agent@openssh.com", 3)) { if (!ssh->agentfwd_enabled) error = "Agent forwarding is not enabled"; else { c->type = CHAN_AGENT; /* identify channel type */ c->u.a.lensofar = 0; } } else { error = "Unsupported channel type requested"; } c->remoteid = remid; c->halfopen = FALSE; if (error) { pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_FAILURE); ssh2_pkt_adduint32(pktout, c->remoteid); ssh2_pkt_adduint32(pktout, SSH2_OPEN_CONNECT_FAILED); ssh2_pkt_addstring(pktout, error); ssh2_pkt_addstring(pktout, "en"); /* language tag */ ssh2_pkt_send(ssh, pktout); logeventf(ssh, "Rejected channel open: %s", error); sfree(c); } else { c->localid = alloc_channel_id(ssh); c->closes = 0; c->v.v2.locwindow = OUR_V2_WINSIZE; c->v.v2.remwindow = winsize; c->v.v2.remmaxpkt = pktsize; bufchain_init(&c->v.v2.outbuffer); add234(ssh->channels, c); pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); ssh2_pkt_adduint32(pktout, c->remoteid); ssh2_pkt_adduint32(pktout, c->localid); ssh2_pkt_adduint32(pktout, c->v.v2.locwindow); ssh2_pkt_adduint32(pktout, OUR_V2_MAXPKT); /* our max pkt size */ ssh2_pkt_send(ssh, pktout); } } /* * Handle the SSH-2 userauth and connection layers. */ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, struct Packet *pktin) { struct do_ssh2_authconn_state { enum { AUTH_INVALID, AUTH_PUBLICKEY_AGENT, AUTH_PUBLICKEY_FILE, AUTH_PASSWORD, AUTH_KEYBOARD_INTERACTIVE } method; enum { AUTH_TYPE_NONE, AUTH_TYPE_PUBLICKEY, AUTH_TYPE_PUBLICKEY_OFFER_LOUD, AUTH_TYPE_PUBLICKEY_OFFER_QUIET, AUTH_TYPE_PASSWORD, AUTH_TYPE_KEYBOARD_INTERACTIVE, AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET } type; int gotit, need_pw, can_pubkey, can_passwd, can_keyb_inter; int tried_pubkey_config, tried_agent; int kbd_inter_running, kbd_inter_refused; int we_are_in; int num_prompts, curr_prompt, echo; char username[100]; int got_username; char pwprompt[512]; char password[100]; void *publickey_blob; int publickey_bloblen; unsigned char request[5], *response, *p; int responselen; int keyi, nkeys; int authed; char *pkblob, *alg, *commentp; int pklen, alglen, commentlen; int siglen, retlen, len; char *q, *agentreq, *ret; int try_send; int num_env, env_left, env_ok; struct Packet *pktout; }; crState(do_ssh2_authconn_state); crBegin(ssh->do_ssh2_authconn_crstate); /* * Request userauth protocol, and await a response to it. */ s->pktout = ssh2_pkt_init(SSH2_MSG_SERVICE_REQUEST); ssh2_pkt_addstring(s->pktout, "ssh-userauth"); ssh2_pkt_send(ssh, s->pktout); crWaitUntilV(pktin); if (pktin->type != SSH2_MSG_SERVICE_ACCEPT) { bombout(("Server refused user authentication protocol")); crStopV; } /* * We repeat this whole loop, including the username prompt, * until we manage a successful authentication. If the user * types the wrong _password_, they can be sent back to the * beginning to try another username, if this is configured on. * (If they specify a username in the config, they are never * asked, even if they do give a wrong password.) * * I think this best serves the needs of * * - the people who have no configuration, no keys, and just * want to try repeated (username,password) pairs until they * type both correctly * * - people who have keys and configuration but occasionally * need to fall back to passwords * * - people with a key held in Pageant, who might not have * logged in to a particular machine before; so they want to * type a username, and then _either_ their key will be * accepted, _or_ they will type a password. If they mistype * the username they will want to be able to get back and * retype it! */ s->username[0] = '\0'; s->got_username = FALSE; do { /* * Get a username. */ if (s->got_username && !ssh->cfg.change_username) { /* * We got a username last time round this loop, and * with change_username turned off we don't try to get * it again. */ } else if (!*ssh->cfg.username) { if (ssh_get_line && !ssh_getline_pw_only) { if (!ssh_get_line("login as: ", s->username, sizeof(s->username), FALSE)) { /* * get_line failed to get a username. * Terminate. */ logevent("No username provided. Abandoning session."); ssh->close_expected = TRUE; ssh_closing((Plug)ssh, NULL, 0, 0); crStopV; } } else { int ret; /* need not be saved across crReturn */ c_write_str(ssh, "login as: "); ssh->send_ok = 1; setup_userpass_input(ssh, s->username, sizeof(s->username), 1); do { crWaitUntilV(!pktin); ret = process_userpass_input(ssh, in, inlen); } while (ret == 0); if (ret < 0) cleanup_exit(0); c_write_str(ssh, "\r\n"); } s->username[strcspn(s->username, "\n\r")] = '\0'; } else { char *stuff; strncpy(s->username, ssh->cfg.username, sizeof(s->username)); s->username[sizeof(s->username)-1] = '\0'; if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) { stuff = dupprintf("Using username \"%s\".\r\n", s->username); c_write_str(ssh, stuff); sfree(stuff); } } s->got_username = TRUE; /* * Send an authentication request using method "none": (a) * just in case it succeeds, and (b) so that we know what * authentication methods we can usefully try next. */ ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK; s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST); ssh2_pkt_addstring(s->pktout, s->username); ssh2_pkt_addstring(s->pktout, "ssh-connection");/* service requested */ ssh2_pkt_addstring(s->pktout, "none"); /* method */ ssh2_pkt_send(ssh, s->pktout); s->type = AUTH_TYPE_NONE; s->gotit = FALSE; s->we_are_in = FALSE; s->tried_pubkey_config = FALSE; s->tried_agent = FALSE; s->kbd_inter_running = FALSE; s->kbd_inter_refused = FALSE; /* Load the pub half of ssh->cfg.keyfile so we notice if it's in Pageant */ if (!filename_is_null(ssh->cfg.keyfile)) { int keytype; logeventf(ssh, "Reading private key file \"%.150s\"", filename_to_str(&ssh->cfg.keyfile)); keytype = key_type(&ssh->cfg.keyfile); if (keytype == SSH_KEYTYPE_SSH2) { s->publickey_blob = ssh2_userkey_loadpub(&ssh->cfg.keyfile, NULL, &s->publickey_bloblen, NULL); } else { char *msgbuf; logeventf(ssh, "Unable to use this key file (%s)", key_type_to_str(keytype)); msgbuf = dupprintf("Unable to use key file \"%.150s\"" " (%s)\r\n", filename_to_str(&ssh->cfg.keyfile), key_type_to_str(keytype)); c_write_str(ssh, msgbuf); sfree(msgbuf); s->publickey_blob = NULL; } } else s->publickey_blob = NULL; while (1) { /* * Wait for the result of the last authentication request. */ if (!s->gotit) crWaitUntilV(pktin); while (pktin->type == SSH2_MSG_USERAUTH_BANNER) { char *banner; int size; /* * Don't show the banner if we're operating in * non-verbose non-interactive mode. (It's probably * a script, which means nobody will read the * banner _anyway_, and moreover the printing of * the banner will screw up processing on the * output of (say) plink.) */ if (flags & (FLAG_VERBOSE | FLAG_INTERACTIVE)) { ssh_pkt_getstring(pktin, &banner, &size); if (banner) c_write_untrusted(ssh, banner, size); } crWaitUntilV(pktin); } if (pktin->type == SSH2_MSG_USERAUTH_SUCCESS) { logevent("Access granted"); s->we_are_in = TRUE; break; } if (s->kbd_inter_running && pktin->type == SSH2_MSG_USERAUTH_INFO_REQUEST) { /* * This is either a further set-of-prompts packet * in keyboard-interactive authentication, or it's * the same one and we came back here with `gotit' * set. In the former case, we must reset the * curr_prompt variable. */ if (!s->gotit) s->curr_prompt = 0; } else if (pktin->type == SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ) { /* FIXME: perhaps we should support this? */ bombout(("PASSWD_CHANGEREQ not yet supported")); crStopV; } else if (pktin->type != SSH2_MSG_USERAUTH_FAILURE) { bombout(("Strange packet received during authentication: type %d", pktin->type)); crStopV; } s->gotit = FALSE; /* * OK, we're now sitting on a USERAUTH_FAILURE message, so * we can look at the string in it and know what we can * helpfully try next. */ if (pktin->type == SSH2_MSG_USERAUTH_FAILURE) { char *methods; int methlen; ssh_pkt_getstring(pktin, &methods, &methlen); s->kbd_inter_running = FALSE; if (!ssh2_pkt_getbool(pktin)) { /* * We have received an unequivocal Access * Denied. This can translate to a variety of * messages: * * - if we'd just tried "none" authentication, * it's not worth printing anything at all * * - if we'd just tried a public key _offer_, * the message should be "Server refused our * key" (or no message at all if the key * came from Pageant) * * - if we'd just tried anything else, the * message really should be "Access denied". * * Additionally, if we'd just tried password * authentication, we should break out of this * whole loop so as to go back to the username * prompt (iff we're configured to allow * username change attempts). */ if (s->type == AUTH_TYPE_NONE) { /* do nothing */ } else if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD || s->type == AUTH_TYPE_PUBLICKEY_OFFER_QUIET) { if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD) c_write_str(ssh, "Server refused our key\r\n"); logevent("Server refused public key"); } else if (s->type==AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET) { /* server declined keyboard-interactive; ignore */ } else { c_write_str(ssh, "Access denied\r\n"); logevent("Access denied"); if (s->type == AUTH_TYPE_PASSWORD && ssh->cfg.change_username) { /* XXX perhaps we should allow * keyboard-interactive to do this too? */ s->we_are_in = FALSE; break; } } } else { c_write_str(ssh, "Further authentication required\r\n"); logevent("Further authentication required"); } s->can_pubkey = in_commasep_string("publickey", methods, methlen); s->can_passwd = in_commasep_string("password", methods, methlen); s->can_keyb_inter = ssh->cfg.try_ki_auth && in_commasep_string("keyboard-interactive", methods, methlen); } s->method = 0; ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK; s->need_pw = FALSE; /* * Most password/passphrase prompts will be * non-echoing, so we set this to 0 by default. * Exception is that some keyboard-interactive prompts * can be echoing, in which case we'll set this to 1. */ s->echo = 0; if (!s->method && s->can_pubkey && agent_exists() && !s->tried_agent) { /* * Attempt public-key authentication using Pageant. */ void *r; s->authed = FALSE; ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK; ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY; s->tried_agent = TRUE; logevent("Pageant is running. Requesting keys."); /* Request the keys held by the agent. */ PUT_32BIT(s->request, 1); s->request[4] = SSH2_AGENTC_REQUEST_IDENTITIES; if (!agent_query(s->request, 5, &r, &s->responselen, ssh_agent_callback, ssh)) { do { crReturnV; if (pktin) { bombout(("Unexpected data from server while" " waiting for agent response")); crStopV; } } while (pktin || inlen > 0); r = ssh->agent_response; s->responselen = ssh->agent_response_len; } s->response = (unsigned char *) r; if (s->response && s->responselen >= 5 && s->response[4] == SSH2_AGENT_IDENTITIES_ANSWER) { s->p = s->response + 5; s->nkeys = GET_32BIT(s->p); s->p += 4; logeventf(ssh, "Pageant has %d SSH-2 keys", s->nkeys); for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) { void *vret; logeventf(ssh, "Trying Pageant key #%d", s->keyi); s->pklen = GET_32BIT(s->p); s->p += 4; if (s->publickey_blob && s->pklen == s->publickey_bloblen && !memcmp(s->p, s->publickey_blob, s->publickey_bloblen)) { logevent("This key matches configured key file"); s->tried_pubkey_config = 1; } s->pkblob = (char *)s->p; s->p += s->pklen; s->alglen = GET_32BIT(s->pkblob); s->alg = s->pkblob + 4; s->commentlen = GET_32BIT(s->p); s->p += 4; s->commentp = (char *)s->p; s->p += s->commentlen; s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST); ssh2_pkt_addstring(s->pktout, s->username); ssh2_pkt_addstring(s->pktout, "ssh-connection"); /* service requested */ ssh2_pkt_addstring(s->pktout, "publickey"); /* method */ ssh2_pkt_addbool(s->pktout, FALSE); /* no signature included */ ssh2_pkt_addstring_start(s->pktout); ssh2_pkt_addstring_data(s->pktout, s->alg, s->alglen); ssh2_pkt_addstring_start(s->pktout); ssh2_pkt_addstring_data(s->pktout, s->pkblob, s->pklen); ssh2_pkt_send(ssh, s->pktout); crWaitUntilV(pktin); if (pktin->type != SSH2_MSG_USERAUTH_PK_OK) { logevent("Key refused"); continue; } if (flags & FLAG_VERBOSE) { c_write_str(ssh, "Authenticating with " "public key \""); c_write(ssh, s->commentp, s->commentlen); c_write_str(ssh, "\" from agent\r\n"); } /* * Server is willing to accept the key. * Construct a SIGN_REQUEST. */ s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST); ssh2_pkt_addstring(s->pktout, s->username); ssh2_pkt_addstring(s->pktout, "ssh-connection"); /* service requested */ ssh2_pkt_addstring(s->pktout, "publickey"); /* method */ ssh2_pkt_addbool(s->pktout, TRUE); ssh2_pkt_addstring_start(s->pktout); ssh2_pkt_addstring_data(s->pktout, s->alg, s->alglen); ssh2_pkt_addstring_start(s->pktout); ssh2_pkt_addstring_data(s->pktout, s->pkblob, s->pklen); s->siglen = s->pktout->length - 5 + 4 + 20; if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID) s->siglen -= 4; s->len = 1; /* message type */ s->len += 4 + s->pklen; /* key blob */ s->len += 4 + s->siglen; /* data to sign */ s->len += 4; /* flags */ s->agentreq = snewn(4 + s->len, char); PUT_32BIT(s->agentreq, s->len); s->q = s->agentreq + 4; *s->q++ = SSH2_AGENTC_SIGN_REQUEST; PUT_32BIT(s->q, s->pklen); s->q += 4; memcpy(s->q, s->pkblob, s->pklen); s->q += s->pklen; PUT_32BIT(s->q, s->siglen); s->q += 4; /* Now the data to be signed... */ if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) { PUT_32BIT(s->q, 20); s->q += 4; } memcpy(s->q, ssh->v2_session_id, 20); s->q += 20; memcpy(s->q, s->pktout->data + 5, s->pktout->length - 5); s->q += s->pktout->length - 5; /* And finally the (zero) flags word. */ PUT_32BIT(s->q, 0); if (!agent_query(s->agentreq, s->len + 4, &vret, &s->retlen, ssh_agent_callback, ssh)) { do { crReturnV; if (pktin) { bombout(("Unexpected data from server" " while waiting for agent" " response")); crStopV; } } while (pktin || inlen > 0); vret = ssh->agent_response; s->retlen = ssh->agent_response_len; } s->ret = vret; sfree(s->agentreq); if (s->ret) { if (s->ret[4] == SSH2_AGENT_SIGN_RESPONSE) { logevent("Sending Pageant's response"); ssh2_add_sigblob(ssh, s->pktout, s->pkblob, s->pklen, s->ret + 9, GET_32BIT(s->ret + 5)); ssh2_pkt_send(ssh, s->pktout); s->authed = TRUE; break; } else { logevent ("Pageant failed to answer challenge"); sfree(s->ret); } } } if (s->authed) continue; } sfree(s->response); } if (!s->method && s->can_pubkey && s->publickey_blob && !s->tried_pubkey_config) { unsigned char *pub_blob; char *algorithm, *comment; int pub_blob_len; s->tried_pubkey_config = TRUE; ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK; ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY; /* * Try the public key supplied in the configuration. * * First, offer the public blob to see if the server is * willing to accept it. */ pub_blob = (unsigned char *)ssh2_userkey_loadpub(&ssh->cfg.keyfile, &algorithm, &pub_blob_len, NULL); if (pub_blob) { s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST); ssh2_pkt_addstring(s->pktout, s->username); ssh2_pkt_addstring(s->pktout, "ssh-connection"); /* service requested */ ssh2_pkt_addstring(s->pktout, "publickey"); /* method */ ssh2_pkt_addbool(s->pktout, FALSE); /* no signature included */ ssh2_pkt_addstring(s->pktout, algorithm); ssh2_pkt_addstring_start(s->pktout); ssh2_pkt_addstring_data(s->pktout, (char *)pub_blob, pub_blob_len); ssh2_pkt_send(ssh, s->pktout); logevent("Offered public key"); crWaitUntilV(pktin); if (pktin->type != SSH2_MSG_USERAUTH_PK_OK) { s->gotit = TRUE; s->type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD; continue; /* key refused; give up on it */ } logevent("Offer of public key accepted"); /* * Actually attempt a serious authentication using * the key. */ if (ssh2_userkey_encrypted(&ssh->cfg.keyfile, &comment)) { sprintf(s->pwprompt, "Passphrase for key \"%.100s\": ", comment); s->need_pw = TRUE; } else { s->need_pw = FALSE; } if (flags & FLAG_VERBOSE) { c_write_str(ssh, "Authenticating with public key \""); c_write_str(ssh, comment); c_write_str(ssh, "\"\r\n"); } s->method = AUTH_PUBLICKEY_FILE; } } if (!s->method && s->can_keyb_inter && !s->kbd_inter_refused && !s->kbd_inter_running) { s->method = AUTH_KEYBOARD_INTERACTIVE; s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE; ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK; ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER; s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST); ssh2_pkt_addstring(s->pktout, s->username); ssh2_pkt_addstring(s->pktout, "ssh-connection"); /* service requested */ ssh2_pkt_addstring(s->pktout, "keyboard-interactive"); /* method */ ssh2_pkt_addstring(s->pktout, ""); /* lang */ ssh2_pkt_addstring(s->pktout, ""); ssh2_pkt_send(ssh, s->pktout); crWaitUntilV(pktin); if (pktin->type != SSH2_MSG_USERAUTH_INFO_REQUEST) { if (pktin->type == SSH2_MSG_USERAUTH_FAILURE) s->gotit = TRUE; logevent("Keyboard-interactive authentication refused"); s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET; s->kbd_inter_refused = TRUE; /* don't try it again */ continue; } c_write_str(ssh, "Using keyboard-interactive authentication.\r\n"); s->kbd_inter_running = TRUE; s->curr_prompt = 0; } if (s->kbd_inter_running) { s->method = AUTH_KEYBOARD_INTERACTIVE; s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE; ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK; ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER; if (s->curr_prompt == 0) { /* * We've got a fresh USERAUTH_INFO_REQUEST. * Display header data, and start going through * the prompts. */ char *name, *inst, *lang; int name_len, inst_len, lang_len; ssh_pkt_getstring(pktin, &name, &name_len); ssh_pkt_getstring(pktin, &inst, &inst_len); ssh_pkt_getstring(pktin, &lang, &lang_len); if (name_len > 0) { c_write_untrusted(ssh, name, name_len); c_write_str(ssh, "\r\n"); } if (inst_len > 0) { c_write_untrusted(ssh, inst, inst_len); c_write_str(ssh, "\r\n"); } s->num_prompts = ssh_pkt_getuint32(pktin); } /* * If there are prompts remaining in the packet, * display one and get a response. */ if (s->curr_prompt < s->num_prompts) { char *prompt; int prompt_len; ssh_pkt_getstring(pktin, &prompt, &prompt_len); if (prompt_len > 0) { static const char trunc[] = ": "; static const int prlen = sizeof(s->pwprompt) - lenof(trunc); if (prompt_len > prlen) { memcpy(s->pwprompt, prompt, prlen); strcpy(s->pwprompt + prlen, trunc); } else { memcpy(s->pwprompt, prompt, prompt_len); s->pwprompt[prompt_len] = '\0'; } } else { strcpy(s->pwprompt, ": "); } s->echo = ssh2_pkt_getbool(pktin); s->need_pw = TRUE; } else s->need_pw = FALSE; } if (!s->method && s->can_passwd) { s->method = AUTH_PASSWORD; ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK; ssh->pkt_ctx |= SSH2_PKTCTX_PASSWORD; sprintf(s->pwprompt, "%.90s@%.90s's password: ", s->username, ssh->savedhost); s->need_pw = TRUE; } if (s->need_pw) { if (ssh_get_line) { if (!ssh_get_line(s->pwprompt, s->password, sizeof(s->password), TRUE)) { /* * get_line failed to get a password (for * example because one was supplied on the * command line which has already failed to * work). Terminate. */ s->pktout = ssh2_pkt_init(SSH2_MSG_DISCONNECT); ssh2_pkt_adduint32(s->pktout,SSH2_DISCONNECT_BY_APPLICATION); ssh2_pkt_addstring(s->pktout, "No more passwords available" " to try"); ssh2_pkt_addstring(s->pktout, "en"); /* language tag */ ssh2_pkt_send_noqueue(ssh, s->pktout); logevent("Unable to authenticate"); connection_fatal(ssh->frontend, "Unable to authenticate"); ssh->close_expected = TRUE; ssh_closing((Plug)ssh, NULL, 0, 0); crStopV; } } else { int ret; /* need not be saved across crReturn */ c_write_untrusted(ssh, s->pwprompt, strlen(s->pwprompt)); ssh->send_ok = 1; setup_userpass_input(ssh, s->password, sizeof(s->password), s->echo); do { crWaitUntilV(!pktin); ret = process_userpass_input(ssh, in, inlen); } while (ret == 0); if (ret < 0) cleanup_exit(0); c_write_str(ssh, "\r\n"); } } if (s->method == AUTH_PUBLICKEY_FILE) { /* * We have our passphrase. Now try the actual authentication. */ struct ssh2_userkey *key; const char *error = NULL; key = ssh2_load_userkey(&ssh->cfg.keyfile, s->password, &error); if (key == SSH2_WRONG_PASSPHRASE || key == NULL) { if (key == SSH2_WRONG_PASSPHRASE) { c_write_str(ssh, "Wrong passphrase\r\n"); s->tried_pubkey_config = FALSE; } else { c_write_str(ssh, "Unable to load private key ("); c_write_str(ssh, error); c_write_str(ssh, ")\r\n"); s->tried_pubkey_config = TRUE; } /* Send a spurious AUTH_NONE to return to the top. */ s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST); ssh2_pkt_addstring(s->pktout, s->username); ssh2_pkt_addstring(s->pktout, "ssh-connection"); /* service requested */ ssh2_pkt_addstring(s->pktout, "none"); /* method */ ssh2_pkt_send(ssh, s->pktout); s->type = AUTH_TYPE_NONE; } else { unsigned char *pkblob, *sigblob, *sigdata; int pkblob_len, sigblob_len, sigdata_len; int p; /* * We have loaded the private key and the server * has announced that it's willing to accept it. * Hallelujah. Generate a signature and send it. */ s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST); ssh2_pkt_addstring(s->pktout, s->username); ssh2_pkt_addstring(s->pktout, "ssh-connection"); /* service requested */ ssh2_pkt_addstring(s->pktout, "publickey"); /* method */ ssh2_pkt_addbool(s->pktout, TRUE); ssh2_pkt_addstring(s->pktout, key->alg->name); pkblob = key->alg->public_blob(key->data, &pkblob_len); ssh2_pkt_addstring_start(s->pktout); ssh2_pkt_addstring_data(s->pktout, (char *)pkblob, pkblob_len); /* * The data to be signed is: * * string session-id * * followed by everything so far placed in the * outgoing packet. */ sigdata_len = s->pktout->length - 5 + 4 + 20; if (ssh->remote_bugs & BUG_SSH2_PK_SESSIONID) sigdata_len -= 4; sigdata = snewn(sigdata_len, unsigned char); p = 0; if (!(ssh->remote_bugs & BUG_SSH2_PK_SESSIONID)) { PUT_32BIT(sigdata+p, 20); p += 4; } memcpy(sigdata+p, ssh->v2_session_id, 20); p += 20; memcpy(sigdata+p, s->pktout->data + 5, s->pktout->length - 5); p += s->pktout->length - 5; assert(p == sigdata_len); sigblob = key->alg->sign(key->data, (char *)sigdata, sigdata_len, &sigblob_len); ssh2_add_sigblob(ssh, s->pktout, pkblob, pkblob_len, sigblob, sigblob_len); sfree(pkblob); sfree(sigblob); sfree(sigdata); ssh2_pkt_send(ssh, s->pktout); s->type = AUTH_TYPE_PUBLICKEY; key->alg->freekey(key->data); } } else if (s->method == AUTH_PASSWORD) { /* * We pad out the password packet to 256 bytes to make * it harder for an attacker to find the length of the * user's password. * * Anyone using a password longer than 256 bytes * probably doesn't have much to worry about from * people who find out how long their password is! */ s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST); s->pktout->forcepad = 256; ssh2_pkt_addstring(s->pktout, s->username); ssh2_pkt_addstring(s->pktout, "ssh-connection"); /* service requested */ ssh2_pkt_addstring(s->pktout, "password"); ssh2_pkt_addbool(s->pktout, FALSE); dont_log_password(ssh, s->pktout, PKTLOG_BLANK); ssh2_pkt_addstring(s->pktout, s->password); memset(s->password, 0, sizeof(s->password)); end_log_omission(ssh, s->pktout); ssh2_pkt_send(ssh, s->pktout); logevent("Sent password"); s->type = AUTH_TYPE_PASSWORD; } else if (s->method == AUTH_KEYBOARD_INTERACTIVE) { if (s->curr_prompt == 0) { s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_INFO_RESPONSE); s->pktout->forcepad = 256; ssh2_pkt_adduint32(s->pktout, s->num_prompts); } if (s->need_pw) { /* only add pw if we just got one! */ dont_log_password(ssh, s->pktout, PKTLOG_BLANK); ssh2_pkt_addstring(s->pktout, s->password); memset(s->password, 0, sizeof(s->password)); end_log_omission(ssh, s->pktout); s->curr_prompt++; } if (s->curr_prompt >= s->num_prompts) { ssh2_pkt_send(ssh, s->pktout); } else { /* * If there are prompts remaining, we set * `gotit' so that we won't attempt to get * another packet. Then we go back round the * loop and will end up retrieving another * prompt out of the existing packet. Funky or * what? */ s->gotit = TRUE; } s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE; } else { c_write_str(ssh, "No supported authentication methods" " left to try!\r\n"); logevent("No supported authentications offered." " Disconnecting"); s->pktout = ssh2_pkt_init(SSH2_MSG_DISCONNECT); ssh2_pkt_adduint32(s->pktout, SSH2_DISCONNECT_BY_APPLICATION); ssh2_pkt_addstring(s->pktout, "No supported authentication" " methods available"); ssh2_pkt_addstring(s->pktout, "en"); /* language tag */ ssh2_pkt_send_noqueue(ssh, s->pktout); ssh->close_expected = TRUE; ssh_closing((Plug)ssh, NULL, 0, 0); crStopV; } } } while (!s->we_are_in); /* * Now we're authenticated for the connection protocol. The * connection protocol will automatically have started at this * point; there's no need to send SERVICE_REQUEST. */ ssh->channels = newtree234(ssh_channelcmp); /* * Set up handlers for some connection protocol messages, so we * don't have to handle them repeatedly in this coroutine. */ ssh->packet_dispatch[SSH2_MSG_CHANNEL_WINDOW_ADJUST] = ssh2_msg_channel_window_adjust; ssh->packet_dispatch[SSH2_MSG_GLOBAL_REQUEST] = ssh2_msg_global_request; /* * Create the main session channel. */ if (!ssh->cfg.ssh_no_shell) { ssh->mainchan = snew(struct ssh_channel); ssh->mainchan->ssh = ssh; ssh->mainchan->localid = alloc_channel_id(ssh); s->pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN); ssh2_pkt_addstring(s->pktout, "session"); ssh2_pkt_adduint32(s->pktout, ssh->mainchan->localid); ssh->mainchan->v.v2.locwindow = OUR_V2_WINSIZE; ssh2_pkt_adduint32(s->pktout, ssh->mainchan->v.v2.locwindow);/* our window size */ ssh2_pkt_adduint32(s->pktout, OUR_V2_MAXPKT); /* our max pkt size */ ssh2_pkt_send(ssh, s->pktout); crWaitUntilV(pktin); if (pktin->type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) { bombout(("Server refused to open a session")); crStopV; /* FIXME: error data comes back in FAILURE packet */ } if (ssh_pkt_getuint32(pktin) != ssh->mainchan->localid) { bombout(("Server's channel confirmation cited wrong channel")); crStopV; } ssh->mainchan->remoteid = ssh_pkt_getuint32(pktin); ssh->mainchan->halfopen = FALSE; ssh->mainchan->type = CHAN_MAINSESSION; ssh->mainchan->closes = 0; ssh->mainchan->v.v2.remwindow = ssh_pkt_getuint32(pktin); ssh->mainchan->v.v2.remmaxpkt = ssh_pkt_getuint32(pktin); bufchain_init(&ssh->mainchan->v.v2.outbuffer); add234(ssh->channels, ssh->mainchan); update_specials_menu(ssh->frontend); logevent("Opened channel for session"); } else ssh->mainchan = NULL; /* * Now we have a channel, make dispatch table entries for * general channel-based messages. */ ssh->packet_dispatch[SSH2_MSG_CHANNEL_DATA] = ssh->packet_dispatch[SSH2_MSG_CHANNEL_EXTENDED_DATA] = ssh2_msg_channel_data; ssh->packet_dispatch[SSH2_MSG_CHANNEL_EOF] = ssh2_msg_channel_eof; ssh->packet_dispatch[SSH2_MSG_CHANNEL_CLOSE] = ssh2_msg_channel_close; ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_CONFIRMATION] = ssh2_msg_channel_open_confirmation; ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_FAILURE] = ssh2_msg_channel_open_failure; ssh->packet_dispatch[SSH2_MSG_CHANNEL_REQUEST] = ssh2_msg_channel_request; ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN] = ssh2_msg_channel_open; /* * Potentially enable X11 forwarding. */ if (ssh->mainchan && ssh->cfg.x11_forward) { char proto[20], data[64]; logevent("Requesting X11 forwarding"); ssh->x11auth = x11_invent_auth(proto, sizeof(proto), data, sizeof(data), ssh->cfg.x11_auth); x11_get_real_auth(ssh->x11auth, ssh->cfg.x11_display); s->pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST); ssh2_pkt_adduint32(s->pktout, ssh->mainchan->remoteid); ssh2_pkt_addstring(s->pktout, "x11-req"); ssh2_pkt_addbool(s->pktout, 1); /* want reply */ ssh2_pkt_addbool(s->pktout, 0); /* many connections */ ssh2_pkt_addstring(s->pktout, proto); ssh2_pkt_addstring(s->pktout, data); ssh2_pkt_adduint32(s->pktout, x11_get_screen_number(ssh->cfg.x11_display)); ssh2_pkt_send(ssh, s->pktout); crWaitUntilV(pktin); if (pktin->type != SSH2_MSG_CHANNEL_SUCCESS) { if (pktin->type != SSH2_MSG_CHANNEL_FAILURE) { bombout(("Unexpected response to X11 forwarding request:" " packet type %d", pktin->type)); crStopV; } logevent("X11 forwarding refused"); } else { logevent("X11 forwarding enabled"); ssh->X11_fwd_enabled = TRUE; } } /* * Enable port forwardings. */ ssh_setup_portfwd(ssh, &ssh->cfg); /* * Potentially enable agent forwarding. */ if (ssh->mainchan && ssh->cfg.agentfwd && agent_exists()) { logevent("Requesting OpenSSH-style agent forwarding"); s->pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST); ssh2_pkt_adduint32(s->pktout, ssh->mainchan->remoteid); ssh2_pkt_addstring(s->pktout, "auth-agent-req@openssh.com"); ssh2_pkt_addbool(s->pktout, 1); /* want reply */ ssh2_pkt_send(ssh, s->pktout); crWaitUntilV(pktin); if (pktin->type != SSH2_MSG_CHANNEL_SUCCESS) { if (pktin->type != SSH2_MSG_CHANNEL_FAILURE) { bombout(("Unexpected response to agent forwarding request:" " packet type %d", pktin->type)); crStopV; } logevent("Agent forwarding refused"); } else { logevent("Agent forwarding enabled"); ssh->agentfwd_enabled = TRUE; } } /* * Now allocate a pty for the session. */ if (ssh->mainchan && !ssh->cfg.nopty) { /* Unpick the terminal-speed string. */ /* XXX perhaps we should allow no speeds to be sent. */ ssh->ospeed = 38400; ssh->ispeed = 38400; /* last-resort defaults */ sscanf(ssh->cfg.termspeed, "%d,%d", &ssh->ospeed, &ssh->ispeed); /* Build the pty request. */ s->pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST); ssh2_pkt_adduint32(s->pktout, ssh->mainchan->remoteid); /* recipient channel */ ssh2_pkt_addstring(s->pktout, "pty-req"); ssh2_pkt_addbool(s->pktout, 1); /* want reply */ ssh2_pkt_addstring(s->pktout, ssh->cfg.termtype); ssh2_pkt_adduint32(s->pktout, ssh->term_width); ssh2_pkt_adduint32(s->pktout, ssh->term_height); ssh2_pkt_adduint32(s->pktout, 0); /* pixel width */ ssh2_pkt_adduint32(s->pktout, 0); /* pixel height */ ssh2_pkt_addstring_start(s->pktout); ssh2_pkt_addbyte(s->pktout, 128); /* TTY_OP_ISPEED */ ssh2_pkt_adduint32(s->pktout, ssh->ispeed); ssh2_pkt_addbyte(s->pktout, 129); /* TTY_OP_OSPEED */ ssh2_pkt_adduint32(s->pktout, ssh->ospeed); ssh2_pkt_addstring_data(s->pktout, "\0", 1); /* TTY_OP_END */ ssh2_pkt_send(ssh, s->pktout); ssh->state = SSH_STATE_INTERMED; crWaitUntilV(pktin); if (pktin->type != SSH2_MSG_CHANNEL_SUCCESS) { if (pktin->type != SSH2_MSG_CHANNEL_FAILURE) { bombout(("Unexpected response to pty request:" " packet type %d", pktin->type)); crStopV; } c_write_str(ssh, "Server refused to allocate pty\r\n"); ssh->editing = ssh->echoing = 1; } else { logeventf(ssh, "Allocated pty (ospeed %dbps, ispeed %dbps)", ssh->ospeed, ssh->ispeed); } } else { ssh->editing = ssh->echoing = 1; } /* * Send environment variables. * * Simplest thing here is to send all the requests at once, and * then wait for a whole bunch of successes or failures. */ if (ssh->mainchan && *ssh->cfg.environmt) { char *e = ssh->cfg.environmt; char *var, *varend, *val; s->num_env = 0; while (*e) { var = e; while (*e && *e != '\t') e++; varend = e; if (*e == '\t') e++; val = e; while (*e) e++; e++; s->pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST); ssh2_pkt_adduint32(s->pktout, ssh->mainchan->remoteid); ssh2_pkt_addstring(s->pktout, "env"); ssh2_pkt_addbool(s->pktout, 1); /* want reply */ ssh2_pkt_addstring_start(s->pktout); ssh2_pkt_addstring_data(s->pktout, var, varend-var); ssh2_pkt_addstring(s->pktout, val); ssh2_pkt_send(ssh, s->pktout); s->num_env++; } logeventf(ssh, "Sent %d environment variables", s->num_env); s->env_ok = 0; s->env_left = s->num_env; while (s->env_left > 0) { crWaitUntilV(pktin); if (pktin->type != SSH2_MSG_CHANNEL_SUCCESS) { if (pktin->type != SSH2_MSG_CHANNEL_FAILURE) { bombout(("Unexpected response to environment request:" " packet type %d", pktin->type)); crStopV; } } else { s->env_ok++; } s->env_left--; } if (s->env_ok == s->num_env) { logevent("All environment variables successfully set"); } else if (s->env_ok == 0) { logevent("All environment variables refused"); c_write_str(ssh, "Server refused to set environment variables\r\n"); } else { logeventf(ssh, "%d environment variables refused", s->num_env - s->env_ok); c_write_str(ssh, "Server refused to set all environment variables\r\n"); } } /* * Start a shell or a remote command. We may have to attempt * this twice if the config data has provided a second choice * of command. */ if (ssh->mainchan) while (1) { int subsys; char *cmd; if (ssh->fallback_cmd) { subsys = ssh->cfg.ssh_subsys2; cmd = ssh->cfg.remote_cmd_ptr2; } else { subsys = ssh->cfg.ssh_subsys; cmd = ssh->cfg.remote_cmd_ptr; if (!cmd) cmd = ssh->cfg.remote_cmd; } s->pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST); ssh2_pkt_adduint32(s->pktout, ssh->mainchan->remoteid); /* recipient channel */ if (subsys) { ssh2_pkt_addstring(s->pktout, "subsystem"); ssh2_pkt_addbool(s->pktout, 1); /* want reply */ ssh2_pkt_addstring(s->pktout, cmd); } else if (*cmd) { ssh2_pkt_addstring(s->pktout, "exec"); ssh2_pkt_addbool(s->pktout, 1); /* want reply */ ssh2_pkt_addstring(s->pktout, cmd); } else { ssh2_pkt_addstring(s->pktout, "shell"); ssh2_pkt_addbool(s->pktout, 1); /* want reply */ } ssh2_pkt_send(ssh, s->pktout); crWaitUntilV(pktin); if (pktin->type != SSH2_MSG_CHANNEL_SUCCESS) { if (pktin->type != SSH2_MSG_CHANNEL_FAILURE) { bombout(("Unexpected response to shell/command request:" " packet type %d", pktin->type)); crStopV; } /* * We failed to start the command. If this is the * fallback command, we really are finished; if it's * not, and if the fallback command exists, try falling * back to it before complaining. */ if (!ssh->fallback_cmd && ssh->cfg.remote_cmd_ptr2 != NULL) { logevent("Primary command failed; attempting fallback"); ssh->fallback_cmd = TRUE; continue; } bombout(("Server refused to start a shell/command")); crStopV; } else { logevent("Started a shell/command"); } break; } ssh->state = SSH_STATE_SESSION; if (ssh->size_needed) ssh_size(ssh, ssh->term_width, ssh->term_height); if (ssh->eof_needed) ssh_special(ssh, TS_EOF); /* * Transfer data! */ if (ssh->ldisc) ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */ if (ssh->mainchan) ssh->send_ok = 1; while (1) { crReturnV; s->try_send = FALSE; if (pktin) { /* * _All_ the connection-layer packets we expect to * receive are now handled by the dispatch table. * Anything that reaches here must be bogus. */ bombout(("Strange packet received: type %d", pktin->type)); crStopV; } else if (ssh->mainchan) { /* * We have spare data. Add it to the channel buffer. */ ssh2_add_channel_data(ssh->mainchan, (char *)in, inlen); s->try_send = TRUE; } if (s->try_send) { int i; struct ssh_channel *c; /* * Try to send data on all channels if we can. */ for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) ssh2_try_send_and_unthrottle(c); } } crFinishV; } /* * Handlers for SSH-2 messages that might arrive at any moment. */ static void ssh2_msg_disconnect(Ssh ssh, struct Packet *pktin) { /* log reason code in disconnect message */ char *buf, *msg; int nowlen, reason, msglen; reason = ssh_pkt_getuint32(pktin); ssh_pkt_getstring(pktin, &msg, &msglen); if (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) { buf = dupprintf("Received disconnect message (%s)", ssh2_disconnect_reasons[reason]); } else { buf = dupprintf("Received disconnect message (unknown" " type %d)", reason); } logevent(buf); sfree(buf); buf = dupprintf("Disconnection message text: %n%.*s", &nowlen, msglen, msg); logevent(buf); bombout(("Server sent disconnect message\ntype %d (%s):\n\"%s\"", reason, (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) ? ssh2_disconnect_reasons[reason] : "unknown", buf+nowlen)); sfree(buf); } static void ssh2_msg_debug(Ssh ssh, struct Packet *pktin) { /* log the debug message */ char *msg; int msglen; int always_display; /* XXX maybe we should actually take notice of this */ always_display = ssh2_pkt_getbool(pktin); ssh_pkt_getstring(pktin, &msg, &msglen); logeventf(ssh, "Remote debug message: %.*s", msglen, msg); } static void ssh2_msg_something_unimplemented(Ssh ssh, struct Packet *pktin) { struct Packet *pktout; pktout = ssh2_pkt_init(SSH2_MSG_UNIMPLEMENTED); ssh2_pkt_adduint32(pktout, pktin->sequence); /* * UNIMPLEMENTED messages MUST appear in the same order as the * messages they respond to. Hence, never queue them. */ ssh2_pkt_send_noqueue(ssh, pktout); } /* * Handle the top-level SSH-2 protocol. */ static void ssh2_protocol_setup(Ssh ssh) { int i; /* * Most messages cause SSH2_MSG_UNIMPLEMENTED. */ for (i = 0; i < 256; i++) ssh->packet_dispatch[i] = ssh2_msg_something_unimplemented; /* * Any message we actually understand, we set to NULL so that * the coroutines will get it. */ ssh->packet_dispatch[SSH2_MSG_UNIMPLEMENTED] = NULL; ssh->packet_dispatch[SSH2_MSG_SERVICE_REQUEST] = NULL; ssh->packet_dispatch[SSH2_MSG_SERVICE_ACCEPT] = NULL; ssh->packet_dispatch[SSH2_MSG_KEXINIT] = NULL; ssh->packet_dispatch[SSH2_MSG_NEWKEYS] = NULL; ssh->packet_dispatch[SSH2_MSG_KEXDH_INIT] = NULL; ssh->packet_dispatch[SSH2_MSG_KEXDH_REPLY] = NULL; /* ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_REQUEST] = NULL; duplicate case value */ /* ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_GROUP] = NULL; duplicate case value */ ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_INIT] = NULL; ssh->packet_dispatch[SSH2_MSG_KEX_DH_GEX_REPLY] = NULL; ssh->packet_dispatch[SSH2_MSG_USERAUTH_REQUEST] = NULL; ssh->packet_dispatch[SSH2_MSG_USERAUTH_FAILURE] = NULL; ssh->packet_dispatch[SSH2_MSG_USERAUTH_SUCCESS] = NULL; ssh->packet_dispatch[SSH2_MSG_USERAUTH_BANNER] = NULL; ssh->packet_dispatch[SSH2_MSG_USERAUTH_PK_OK] = NULL; /* ssh->packet_dispatch[SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ] = NULL; duplicate case value */ /* ssh->packet_dispatch[SSH2_MSG_USERAUTH_INFO_REQUEST] = NULL; duplicate case value */ ssh->packet_dispatch[SSH2_MSG_USERAUTH_INFO_RESPONSE] = NULL; ssh->packet_dispatch[SSH2_MSG_GLOBAL_REQUEST] = NULL; ssh->packet_dispatch[SSH2_MSG_REQUEST_SUCCESS] = NULL; ssh->packet_dispatch[SSH2_MSG_REQUEST_FAILURE] = NULL; ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN] = NULL; ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_CONFIRMATION] = NULL; ssh->packet_dispatch[SSH2_MSG_CHANNEL_OPEN_FAILURE] = NULL; ssh->packet_dispatch[SSH2_MSG_CHANNEL_WINDOW_ADJUST] = NULL; ssh->packet_dispatch[SSH2_MSG_CHANNEL_DATA] = NULL; ssh->packet_dispatch[SSH2_MSG_CHANNEL_EXTENDED_DATA] = NULL; ssh->packet_dispatch[SSH2_MSG_CHANNEL_EOF] = NULL; ssh->packet_dispatch[SSH2_MSG_CHANNEL_CLOSE] = NULL; ssh->packet_dispatch[SSH2_MSG_CHANNEL_REQUEST] = NULL; ssh->packet_dispatch[SSH2_MSG_CHANNEL_SUCCESS] = NULL; ssh->packet_dispatch[SSH2_MSG_CHANNEL_FAILURE] = NULL; /* * These special message types we install handlers for. */ ssh->packet_dispatch[SSH2_MSG_DISCONNECT] = ssh2_msg_disconnect; ssh->packet_dispatch[SSH2_MSG_IGNORE] = ssh_msg_ignore; /* shared with SSH-1 */ ssh->packet_dispatch[SSH2_MSG_DEBUG] = ssh2_msg_debug; } static void ssh2_timer(void *ctx, long now) { Ssh ssh = (Ssh)ctx; if (ssh->state == SSH_STATE_CLOSED) return; if (!ssh->kex_in_progress && ssh->cfg.ssh_rekey_time != 0 && now - ssh->next_rekey >= 0) { do_ssh2_transport(ssh, "timeout", -1, NULL); } } static void ssh2_protocol(Ssh ssh, void *vin, int inlen, struct Packet *pktin) { unsigned char *in = (unsigned char *)vin; if (ssh->state == SSH_STATE_CLOSED) return; if (pktin) { ssh->incoming_data_size += pktin->encrypted_len; if (!ssh->kex_in_progress && ssh->max_data_size != 0 && ssh->incoming_data_size > ssh->max_data_size) do_ssh2_transport(ssh, "too much data received", -1, NULL); } if (pktin && ssh->packet_dispatch[pktin->type]) { ssh->packet_dispatch[pktin->type](ssh, pktin); return; } if (!ssh->protocol_initial_phase_done || (pktin && pktin->type >= 20 && pktin->type < 50)) { if (do_ssh2_transport(ssh, in, inlen, pktin) && !ssh->protocol_initial_phase_done) { ssh->protocol_initial_phase_done = TRUE; /* * Allow authconn to initialise itself. */ do_ssh2_authconn(ssh, NULL, 0, NULL); } } else { do_ssh2_authconn(ssh, in, inlen, pktin); } } /* * Called to set up the connection. * * Returns an error message, or NULL on success. */ static const char *ssh_init(void *frontend_handle, void **backend_handle, Config *cfg, char *host, int port, char **realhost, int nodelay, int keepalive) { const char *p; Ssh ssh; ssh = snew(struct ssh_tag); ssh->cfg = *cfg; /* STRUCTURE COPY */ ssh->version = 0; /* when not ready yet */ ssh->s = NULL; ssh->cipher = NULL; ssh->v1_cipher_ctx = NULL; ssh->crcda_ctx = NULL; ssh->cscipher = NULL; ssh->cs_cipher_ctx = NULL; ssh->sccipher = NULL; ssh->sc_cipher_ctx = NULL; ssh->csmac = NULL; ssh->cs_mac_ctx = NULL; ssh->scmac = NULL; ssh->sc_mac_ctx = NULL; ssh->cscomp = NULL; ssh->cs_comp_ctx = NULL; ssh->sccomp = NULL; ssh->sc_comp_ctx = NULL; ssh->kex = NULL; ssh->kex_ctx = NULL; ssh->hostkey = NULL; ssh->exitcode = -1; ssh->close_expected = FALSE; ssh->state = SSH_STATE_PREPACKET; ssh->size_needed = FALSE; ssh->eof_needed = FALSE; ssh->ldisc = NULL; ssh->logctx = NULL; ssh->deferred_send_data = NULL; ssh->deferred_len = 0; ssh->deferred_size = 0; ssh->fallback_cmd = 0; ssh->pkt_ctx = 0; ssh->x11auth = NULL; ssh->v1_compressing = FALSE; ssh->v2_outgoing_sequence = 0; ssh->ssh1_rdpkt_crstate = 0; ssh->ssh2_rdpkt_crstate = 0; ssh->do_ssh_init_crstate = 0; ssh->ssh_gotdata_crstate = 0; ssh->do_ssh1_connection_crstate = 0; ssh->do_ssh1_login_crstate = 0; ssh->do_ssh2_transport_crstate = 0; ssh->do_ssh2_authconn_crstate = 0; ssh->do_ssh_init_state = NULL; ssh->do_ssh1_login_state = NULL; ssh->do_ssh2_transport_state = NULL; ssh->do_ssh2_authconn_state = NULL; ssh->mainchan = NULL; ssh->throttled_all = 0; ssh->v1_stdout_throttling = 0; ssh->queue = NULL; ssh->queuelen = ssh->queuesize = 0; ssh->queueing = FALSE; ssh->qhead = ssh->qtail = NULL; ssh->deferred_rekey_reason = NULL; bufchain_init(&ssh->queued_incoming_data); ssh->frozen = FALSE; *backend_handle = ssh; #ifdef MSCRYPTOAPI if (crypto_startup() == 0) return "Microsoft high encryption pack not installed!"; #endif ssh->frontend = frontend_handle; ssh->term_width = ssh->cfg.width; ssh->term_height = ssh->cfg.height; ssh->channels = NULL; ssh->rportfwds = NULL; ssh->portfwds = NULL; ssh->send_ok = 0; ssh->editing = 0; ssh->echoing = 0; ssh->v1_throttle_count = 0; ssh->overall_bufsize = 0; ssh->fallback_cmd = 0; ssh->protocol = NULL; ssh->protocol_initial_phase_done = FALSE; ssh->pinger = NULL; ssh->incoming_data_size = ssh->outgoing_data_size = ssh->deferred_data_size = 0L; ssh->max_data_size = parse_blocksize(ssh->cfg.ssh_rekey_data); ssh->kex_in_progress = FALSE; p = connect_to_host(ssh, host, port, realhost, nodelay, keepalive); if (p != NULL) return p; random_ref(); return NULL; } static void ssh_free(void *handle) { Ssh ssh = (Ssh) handle; struct ssh_channel *c; struct ssh_rportfwd *pf; if (ssh->v1_cipher_ctx) ssh->cipher->free_context(ssh->v1_cipher_ctx); if (ssh->cs_cipher_ctx) ssh->cscipher->free_context(ssh->cs_cipher_ctx); if (ssh->sc_cipher_ctx) ssh->sccipher->free_context(ssh->sc_cipher_ctx); if (ssh->cs_mac_ctx) ssh->csmac->free_context(ssh->cs_mac_ctx); if (ssh->sc_mac_ctx) ssh->scmac->free_context(ssh->sc_mac_ctx); if (ssh->cs_comp_ctx) { if (ssh->cscomp) ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx); else zlib_compress_cleanup(ssh->cs_comp_ctx); } if (ssh->sc_comp_ctx) { if (ssh->sccomp) ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx); else zlib_decompress_cleanup(ssh->sc_comp_ctx); } if (ssh->kex_ctx) dh_cleanup(ssh->kex_ctx); sfree(ssh->savedhost); while (ssh->queuelen-- > 0) ssh_free_packet(ssh->queue[ssh->queuelen]); sfree(ssh->queue); while (ssh->qhead) { struct queued_handler *qh = ssh->qhead; ssh->qhead = qh->next; sfree(ssh->qhead); } ssh->qhead = ssh->qtail = NULL; if (ssh->channels) { while ((c = delpos234(ssh->channels, 0)) != NULL) { switch (c->type) { case CHAN_X11: if (c->u.x11.s != NULL) x11_close(c->u.x11.s); break; case CHAN_SOCKDATA: if (c->u.pfd.s != NULL) pfd_close(c->u.pfd.s); break; } sfree(c); } freetree234(ssh->channels); ssh->channels = NULL; } if (ssh->rportfwds) { while ((pf = delpos234(ssh->rportfwds, 0)) != NULL) sfree(pf); freetree234(ssh->rportfwds); ssh->rportfwds = NULL; } sfree(ssh->deferred_send_data); if (ssh->x11auth) x11_free_auth(ssh->x11auth); sfree(ssh->do_ssh_init_state); sfree(ssh->do_ssh1_login_state); sfree(ssh->do_ssh2_transport_state); sfree(ssh->do_ssh2_authconn_state); if (ssh->crcda_ctx) { crcda_free_context(ssh->crcda_ctx); ssh->crcda_ctx = NULL; } if (ssh->s) ssh_do_close(ssh, TRUE); expire_timer_context(ssh); if (ssh->pinger) pinger_free(ssh->pinger); bufchain_clear(&ssh->queued_incoming_data); sfree(ssh); random_unref(); } /* * Reconfigure the SSH backend. */ static void ssh_reconfig(void *handle, Config *cfg) { Ssh ssh = (Ssh) handle; char *rekeying = NULL, rekey_mandatory = FALSE; unsigned long old_max_data_size; pinger_reconfig(ssh->pinger, &ssh->cfg, cfg); ssh_setup_portfwd(ssh, cfg); if (ssh->cfg.ssh_rekey_time != cfg->ssh_rekey_time && cfg->ssh_rekey_time != 0) { long new_next = ssh->last_rekey + cfg->ssh_rekey_time*60*TICKSPERSEC; long now = GETTICKCOUNT(); if (new_next - now < 0) { rekeying = "timeout shortened"; } else { ssh->next_rekey = schedule_timer(new_next - now, ssh2_timer, ssh); } } old_max_data_size = ssh->max_data_size; ssh->max_data_size = parse_blocksize(cfg->ssh_rekey_data); if (old_max_data_size != ssh->max_data_size && ssh->max_data_size != 0) { if (ssh->outgoing_data_size > ssh->max_data_size || ssh->incoming_data_size > ssh->max_data_size) rekeying = "data limit lowered"; } if (ssh->cfg.compression != cfg->compression) { rekeying = "compression setting changed"; rekey_mandatory = TRUE; } if (ssh->cfg.ssh2_des_cbc != cfg->ssh2_des_cbc || memcmp(ssh->cfg.ssh_cipherlist, cfg->ssh_cipherlist, sizeof(ssh->cfg.ssh_cipherlist))) { rekeying = "cipher settings changed"; rekey_mandatory = TRUE; } ssh->cfg = *cfg; /* STRUCTURE COPY */ if (rekeying) { if (!ssh->kex_in_progress) { do_ssh2_transport(ssh, rekeying, -1, NULL); } else if (rekey_mandatory) { ssh->deferred_rekey_reason = rekeying; } } } /* * Called to send data down the Telnet connection. */ static int ssh_send(void *handle, char *buf, int len) { Ssh ssh = (Ssh) handle; if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL) return 0; ssh->protocol(ssh, (unsigned char *)buf, len, 0); return ssh_sendbuffer(ssh); } /* * Called to query the current amount of buffered stdin data. */ static int ssh_sendbuffer(void *handle) { Ssh ssh = (Ssh) handle; int override_value; if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL) return 0; /* * If the SSH socket itself has backed up, add the total backup * size on that to any individual buffer on the stdin channel. */ override_value = 0; if (ssh->throttled_all) override_value = ssh->overall_bufsize; if (ssh->version == 1) { return override_value; } else if (ssh->version == 2) { if (!ssh->mainchan || ssh->mainchan->closes > 0) return override_value; else return (override_value + bufchain_size(&ssh->mainchan->v.v2.outbuffer)); } return 0; } /* * Called to set the size of the window from SSH's POV. */ static void ssh_size(void *handle, int width, int height) { Ssh ssh = (Ssh) handle; struct Packet *pktout; ssh->term_width = width; ssh->term_height = height; switch (ssh->state) { case SSH_STATE_BEFORE_SIZE: case SSH_STATE_PREPACKET: case SSH_STATE_CLOSED: break; /* do nothing */ case SSH_STATE_INTERMED: ssh->size_needed = TRUE; /* buffer for later */ break; case SSH_STATE_SESSION: if (!ssh->cfg.nopty) { if (ssh->version == 1) { send_packet(ssh, SSH1_CMSG_WINDOW_SIZE, PKT_INT, ssh->term_height, PKT_INT, ssh->term_width, PKT_INT, 0, PKT_INT, 0, PKT_END); } else if (ssh->mainchan) { pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST); ssh2_pkt_adduint32(pktout, ssh->mainchan->remoteid); ssh2_pkt_addstring(pktout, "window-change"); ssh2_pkt_addbool(pktout, 0); ssh2_pkt_adduint32(pktout, ssh->term_width); ssh2_pkt_adduint32(pktout, ssh->term_height); ssh2_pkt_adduint32(pktout, 0); ssh2_pkt_adduint32(pktout, 0); ssh2_pkt_send(ssh, pktout); } } break; } } /* * Return a list of the special codes that make sense in this * protocol. */ static const struct telnet_special *ssh_get_specials(void *handle) { static const struct telnet_special ssh1_ignore_special[] = { {"IGNORE message", TS_NOP} }; static const struct telnet_special ssh2_transport_specials[] = { {"IGNORE message", TS_NOP}, {"Repeat key exchange", TS_REKEY}, }; static const struct telnet_special ssh2_session_specials[] = { {NULL, TS_SEP}, {"Break", TS_BRK}, /* These are the signal names defined by draft-ietf-secsh-connect-23. * They include all the ISO C signals, but are a subset of the POSIX * required signals. */ {"SIGINT (Interrupt)", TS_SIGINT}, {"SIGTERM (Terminate)", TS_SIGTERM}, {"SIGKILL (Kill)", TS_SIGKILL}, {"SIGQUIT (Quit)", TS_SIGQUIT}, {"SIGHUP (Hangup)", TS_SIGHUP}, {"More signals", TS_SUBMENU}, {"SIGABRT", TS_SIGABRT}, {"SIGALRM", TS_SIGALRM}, {"SIGFPE", TS_SIGFPE}, {"SIGILL", TS_SIGILL}, {"SIGPIPE", TS_SIGPIPE}, {"SIGSEGV", TS_SIGSEGV}, {"SIGUSR1", TS_SIGUSR1}, {"SIGUSR2", TS_SIGUSR2}, {NULL, TS_EXITMENU} }; static const struct telnet_special specials_end[] = { {NULL, TS_EXITMENU} }; /* XXX review this length for any changes: */ static struct telnet_special ssh_specials[lenof(ssh2_transport_specials) + lenof(ssh2_session_specials) + lenof(specials_end)]; Ssh ssh = (Ssh) handle; int i = 0; #define ADD_SPECIALS(name) \ do { \ assert((i + lenof(name)) <= lenof(ssh_specials)); \ memcpy(&ssh_specials[i], name, sizeof name); \ i += lenof(name); \ } while(0) if (ssh->version == 1) { /* Don't bother offering IGNORE if we've decided the remote * won't cope with it, since we wouldn't bother sending it if * asked anyway. */ if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE)) ADD_SPECIALS(ssh1_ignore_special); } else if (ssh->version == 2) { ADD_SPECIALS(ssh2_transport_specials); if (ssh->mainchan) ADD_SPECIALS(ssh2_session_specials); } /* else we're not ready yet */ if (i) { ADD_SPECIALS(specials_end); return ssh_specials; } else { return NULL; } #undef ADD_SPECIALS } /* * Send Telnet special codes. TS_EOF is useful for `plink', so you * can send an EOF and collect resulting output (e.g. `plink * hostname sort'). */ static void ssh_special(void *handle, Telnet_Special code) { Ssh ssh = (Ssh) handle; struct Packet *pktout; if (code == TS_EOF) { if (ssh->state != SSH_STATE_SESSION) { /* * Buffer the EOF in case we are pre-SESSION, so we can * send it as soon as we reach SESSION. */ if (code == TS_EOF) ssh->eof_needed = TRUE; return; } if (ssh->version == 1) { send_packet(ssh, SSH1_CMSG_EOF, PKT_END); } else if (ssh->mainchan) { struct Packet *pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_EOF); ssh2_pkt_adduint32(pktout, ssh->mainchan->remoteid); ssh2_pkt_send(ssh, pktout); ssh->send_ok = 0; /* now stop trying to read from stdin */ } logevent("Sent EOF message"); } else if (code == TS_PING || code == TS_NOP) { if (ssh->state == SSH_STATE_CLOSED || ssh->state == SSH_STATE_PREPACKET) return; if (ssh->version == 1) { if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE)) send_packet(ssh, SSH1_MSG_IGNORE, PKT_STR, "", PKT_END); } else { pktout = ssh2_pkt_init(SSH2_MSG_IGNORE); ssh2_pkt_addstring_start(pktout); ssh2_pkt_send_noqueue(ssh, pktout); } } else if (code == TS_REKEY) { if (!ssh->kex_in_progress && ssh->version == 2) { do_ssh2_transport(ssh, "at user request", -1, NULL); } } else if (code == TS_BRK) { if (ssh->state == SSH_STATE_CLOSED || ssh->state == SSH_STATE_PREPACKET) return; if (ssh->version == 1) { logevent("Unable to send BREAK signal in SSH-1"); } else if (ssh->mainchan) { pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST); ssh2_pkt_adduint32(pktout, ssh->mainchan->remoteid); ssh2_pkt_addstring(pktout, "break"); ssh2_pkt_addbool(pktout, 0); ssh2_pkt_adduint32(pktout, 0); /* default break length */ ssh2_pkt_send(ssh, pktout); } } else { /* Is is a POSIX signal? */ char *signame = NULL; if (code == TS_SIGABRT) signame = "ABRT"; if (code == TS_SIGALRM) signame = "ALRM"; if (code == TS_SIGFPE) signame = "FPE"; if (code == TS_SIGHUP) signame = "HUP"; if (code == TS_SIGILL) signame = "ILL"; if (code == TS_SIGINT) signame = "INT"; if (code == TS_SIGKILL) signame = "KILL"; if (code == TS_SIGPIPE) signame = "PIPE"; if (code == TS_SIGQUIT) signame = "QUIT"; if (code == TS_SIGSEGV) signame = "SEGV"; if (code == TS_SIGTERM) signame = "TERM"; if (code == TS_SIGUSR1) signame = "USR1"; if (code == TS_SIGUSR2) signame = "USR2"; /* The SSH-2 protocol does in principle support arbitrary named * signals, including signame@domain, but we don't support those. */ if (signame) { /* It's a signal. */ if (ssh->version == 2 && ssh->mainchan) { pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST); ssh2_pkt_adduint32(pktout, ssh->mainchan->remoteid); ssh2_pkt_addstring(pktout, "signal"); ssh2_pkt_addbool(pktout, 0); ssh2_pkt_addstring(pktout, signame); ssh2_pkt_send(ssh, pktout); logeventf(ssh, "Sent signal SIG%s", signame); } } else { /* Never heard of it. Do nothing */ } } } void *new_sock_channel(void *handle, Socket s) { Ssh ssh = (Ssh) handle; struct ssh_channel *c; c = snew(struct ssh_channel); c->ssh = ssh; if (c) { c->halfopen = TRUE; c->localid = alloc_channel_id(ssh); c->closes = 0; c->type = CHAN_SOCKDATA_DORMANT;/* identify channel type */ c->u.pfd.s = s; bufchain_init(&c->v.v2.outbuffer); add234(ssh->channels, c); } return c; } /* * This is called when stdout/stderr (the entity to which * from_backend sends data) manages to clear some backlog. */ static void ssh_unthrottle(void *handle, int bufsize) { Ssh ssh = (Ssh) handle; if (ssh->version == 1) { if (ssh->v1_stdout_throttling && bufsize < SSH1_BUFFER_LIMIT) { ssh->v1_stdout_throttling = 0; ssh1_throttle(ssh, -1); } } else { if (ssh->mainchan && ssh->mainchan->closes == 0) ssh2_set_window(ssh->mainchan, OUR_V2_WINSIZE - bufsize); } } void ssh_send_port_open(void *channel, char *hostname, int port, char *org) { struct ssh_channel *c = (struct ssh_channel *)channel; Ssh ssh = c->ssh; struct Packet *pktout; logeventf(ssh, "Opening forwarded connection to %s:%d", hostname, port); if (ssh->version == 1) { send_packet(ssh, SSH1_MSG_PORT_OPEN, PKT_INT, c->localid, PKT_STR, hostname, PKT_INT, port, /* PKT_STR, , */ PKT_END); } else { pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN); ssh2_pkt_addstring(pktout, "direct-tcpip"); ssh2_pkt_adduint32(pktout, c->localid); c->v.v2.locwindow = OUR_V2_WINSIZE; ssh2_pkt_adduint32(pktout, c->v.v2.locwindow);/* our window size */ ssh2_pkt_adduint32(pktout, OUR_V2_MAXPKT); /* our max pkt size */ ssh2_pkt_addstring(pktout, hostname); ssh2_pkt_adduint32(pktout, port); /* * We make up values for the originator data; partly it's * too much hassle to keep track, and partly I'm not * convinced the server should be told details like that * about my local network configuration. */ ssh2_pkt_addstring(pktout, "client-side-connection"); ssh2_pkt_adduint32(pktout, 0); ssh2_pkt_send(ssh, pktout); } } static Socket ssh_socket(void *handle) { Ssh ssh = (Ssh) handle; return ssh->s; } static int ssh_sendok(void *handle) { Ssh ssh = (Ssh) handle; return ssh->send_ok; } static int ssh_ldisc(void *handle, int option) { Ssh ssh = (Ssh) handle; if (option == LD_ECHO) return ssh->echoing; if (option == LD_EDIT) return ssh->editing; return FALSE; } static void ssh_provide_ldisc(void *handle, void *ldisc) { Ssh ssh = (Ssh) handle; ssh->ldisc = ldisc; } static void ssh_provide_logctx(void *handle, void *logctx) { Ssh ssh = (Ssh) handle; ssh->logctx = logctx; } static int ssh_return_exitcode(void *handle) { Ssh ssh = (Ssh) handle; if (ssh->s != NULL) return -1; else return (ssh->exitcode >= 0 ? ssh->exitcode : 0); } /* * cfg_info for SSH is the currently running version of the * protocol. (1 for 1; 2 for 2; 0 for not-decided-yet.) */ static int ssh_cfg_info(void *handle) { Ssh ssh = (Ssh) handle; return ssh->version; } /* * Gross hack: pscp will try to start SFTP but fall back to scp1 if * that fails. This variable is the means by which scp.c can reach * into the SSH code and find out which one it got. */ extern int ssh_fallback_cmd(void *handle) { Ssh ssh = (Ssh) handle; return ssh->fallback_cmd; } Backend ssh_backend = { ssh_init, ssh_free, ssh_reconfig, ssh_send, ssh_sendbuffer, ssh_size, ssh_special, ssh_get_specials, ssh_socket, ssh_return_exitcode, ssh_sendok, ssh_ldisc, ssh_provide_ldisc, ssh_provide_logctx, ssh_unthrottle, ssh_cfg_info, 22 };