#include #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 logevent(s) { logevent(s); \ if ((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)) \ fprintf(stderr, "%s\n", s); } #define bombout(msg) ( ssh_state = SSH_STATE_CLOSED, \ (s ? sk_close(s), s = NULL : 0), \ connection_fatal msg ) #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_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 */ #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_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 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); } enum { PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR, PKT_BIGNUM }; /* Coroutine mechanics for the sillier bits of the code */ #define crBegin1 static int crLine = 0; #define crBegin2 switch(crLine) { case 0:; #define crBegin crBegin1; crBegin2; #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)) extern char *x11_init (Socket *, char *, void *); extern void x11_close (Socket); extern void x11_send (Socket , char *, int); extern void x11_invent_auth(char *, int, char *, int); /* * Ciphers for SSH2. We miss out single-DES because it isn't * supported; also 3DES and Blowfish are both done differently from * SSH1. (3DES uses outer chaining; Blowfish has the opposite * endianness and different-sized keys.) */ const static struct ssh2_ciphers *ciphers[] = { &ssh2_aes, &ssh2_blowfish, &ssh2_3des, }; const static struct ssh_kex *kex_algs[] = { &ssh_diffiehellman_gex, &ssh_diffiehellman }; const static struct ssh_signkey *hostkey_algs[] = { &ssh_rsa, &ssh_dss }; static void nullmac_key(unsigned char *key) { } static void nullmac_generate(unsigned char *blk, int len, unsigned long seq) { } static int nullmac_verify(unsigned char *blk, int len, unsigned long seq) { return 1; } const static struct ssh_mac ssh_mac_none = { nullmac_key, 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) { } static int ssh_comp_none_block(unsigned char *block, int len, unsigned char **outblock, int *outlen) { return 0; } static int ssh_comp_none_disable(void) { return 0; } const static struct ssh_compress ssh_comp_none = { "none", ssh_comp_none_init, ssh_comp_none_block, ssh_comp_none_init, ssh_comp_none_block, ssh_comp_none_disable }; 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, }; /* * 2-3-4 tree storing channels. */ struct ssh_channel { unsigned remoteid, localid; int type; int closes; struct ssh2_data_channel { unsigned char *outbuffer; unsigned outbuflen, outbufsize; unsigned remwindow, remmaxpkt; } v2; union { struct ssh_agent_channel { unsigned char *message; unsigned char msglen[4]; int lensofar, totallen; } a; struct ssh_x11_channel { Socket s; } x11; } u; }; struct Packet { long length; int type; unsigned char *data; unsigned char *body; long savedpos; long maxlen; }; static SHA_State exhash, exhashbase; static Socket s = NULL; static unsigned char session_key[32]; static int ssh1_compressing; static int ssh1_remote_protoflags; static int ssh1_local_protoflags; static int ssh_agentfwd_enabled; static int ssh_X11_fwd_enabled; static int ssh_remote_bugs; static const struct ssh_cipher *cipher = NULL; static const struct ssh2_cipher *cscipher = NULL; static const struct ssh2_cipher *sccipher = NULL; static const struct ssh_mac *csmac = NULL; static const struct ssh_mac *scmac = NULL; static const struct ssh_compress *cscomp = NULL; static const struct ssh_compress *sccomp = NULL; static const struct ssh_kex *kex = NULL; static const struct ssh_signkey *hostkey = NULL; static unsigned char ssh2_session_id[20]; int (*ssh_get_line)(const char *prompt, char *str, int maxlen, int is_pw) = NULL; static char *savedhost; static int savedport; static int ssh_send_ok; static int ssh_echoing, ssh_editing; static tree234 *ssh_channels; /* indexed by local id */ static struct ssh_channel *mainchan; /* primary session channel */ static enum { SSH_STATE_PREPACKET, SSH_STATE_BEFORE_SIZE, SSH_STATE_INTERMED, SSH_STATE_SESSION, SSH_STATE_CLOSED } ssh_state = SSH_STATE_PREPACKET; static int size_needed = FALSE, eof_needed = FALSE; static struct Packet pktin = { 0, 0, NULL, NULL, 0 }; static struct Packet pktout = { 0, 0, NULL, NULL, 0 }; static unsigned char *deferred_send_data = NULL; static int deferred_len = 0, deferred_size = 0; static int ssh_version; static void (*ssh_protocol)(unsigned char *in, int inlen, int ispkt); static void ssh1_protocol(unsigned char *in, int inlen, int ispkt); static void ssh2_protocol(unsigned char *in, int inlen, int ispkt); static void ssh_size(void); static void ssh_special (Telnet_Special); static void ssh2_try_send(struct ssh_channel *c); static void ssh2_add_channel_data(struct ssh_channel *c, char *buf, int len); static int (*s_rdpkt)(unsigned char **data, int *datalen); static struct rdpkt1_state_tag { long len, pad, biglen, to_read; unsigned long realcrc, gotcrc; unsigned char *p; int i; int chunk; } rdpkt1_state; static struct rdpkt2_state_tag { long len, pad, payload, packetlen, maclen; int i; int cipherblk; unsigned long incoming_sequence; } rdpkt2_state; 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 void c_write (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(1, buf, len); } static void c_write_untrusted(char *buf, int len) { int i; for (i = 0; i < len; i++) { if (buf[i] == '\n') c_write("\r\n", 2); else if ((buf[i] & 0x60) || (buf[i] == '\r')) c_write(buf+i, 1); } } static void c_write_str (char *buf) { c_write(buf, strlen(buf)); } /* * 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 the additional nr of bytes needed, or 0 when * a complete packet is available. */ static int ssh1_rdpkt(unsigned char **data, int *datalen) { struct rdpkt1_state_tag *st = &rdpkt1_state; crBegin; next_packet: pktin.type = 0; pktin.length = 0; for (st->i = st->len = 0; st->i < 4; st->i++) { while ((*datalen) == 0) crReturn(4-st->i); st->len = (st->len << 8) + **data; (*data)++, (*datalen)--; } #ifdef FWHACK if (st->len == 0x52656d6f) { /* "Remo"te server has closed ... */ st->len = 0x300; /* big enough to carry to end */ } #endif st->pad = 8 - (st->len % 8); st->biglen = st->len + st->pad; pktin.length = st->len - 5; if (pktin.maxlen < st->biglen) { pktin.maxlen = st->biglen; pktin.data = (pktin.data == NULL ? smalloc(st->biglen+APIEXTRA) : srealloc(pktin.data, st->biglen+APIEXTRA)); if (!pktin.data) fatalbox("Out of memory"); } st->to_read = st->biglen; st->p = pktin.data; while (st->to_read > 0) { st->chunk = st->to_read; while ((*datalen) == 0) crReturn(st->to_read); 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 (cipher) cipher->decrypt(pktin.data, st->biglen); #if 0 debug(("Got packet len=%d pad=%d\r\n", st->len, st->pad)); for (st->i = 0; st->i < st->biglen; st->i++) debug((" %02x", (unsigned char)pktin.data[st->i])); debug(("\r\n")); #endif st->realcrc = crc32(pktin.data, st->biglen-4); st->gotcrc = GET_32BIT(pktin.data+st->biglen-4); if (st->gotcrc != st->realcrc) { bombout(("Incorrect CRC received on packet")); crReturn(0); } pktin.body = pktin.data + st->pad + 1; if (ssh1_compressing) { unsigned char *decompblk; int decomplen; #if 0 { int i; debug(("Packet payload pre-decompression:\n")); for (i = -1; i < pktin.length; i++) debug((" %02x", (unsigned char)pktin.body[i])); debug(("\r\n")); } #endif zlib_decompress_block(pktin.body-1, pktin.length+1, &decompblk, &decomplen); if (pktin.maxlen < st->pad + decomplen) { pktin.maxlen = st->pad + decomplen; pktin.data = srealloc(pktin.data, pktin.maxlen+APIEXTRA); pktin.body = pktin.data + st->pad + 1; if (!pktin.data) fatalbox("Out of memory"); } memcpy(pktin.body-1, decompblk, decomplen); sfree(decompblk); pktin.length = decomplen-1; #if 0 { int i; debug(("Packet payload post-decompression:\n")); for (i = -1; i < pktin.length; i++) debug((" %02x", (unsigned char)pktin.body[i])); debug(("\r\n")); } #endif } if (pktin.type == SSH1_SMSG_STDOUT_DATA || pktin.type == SSH1_SMSG_STDERR_DATA || pktin.type == SSH1_MSG_DEBUG || pktin.type == SSH1_SMSG_AUTH_TIS_CHALLENGE || pktin.type == SSH1_SMSG_AUTH_CCARD_CHALLENGE) { long strlen = GET_32BIT(pktin.body); if (strlen + 4 != pktin.length) { bombout(("Received data packet with bogus string length")); crReturn(0); } } pktin.type = pktin.body[-1]; if (pktin.type == SSH1_MSG_DEBUG) { /* log debug message */ char buf[80]; int strlen = GET_32BIT(pktin.body); strcpy(buf, "Remote: "); if (strlen > 70) strlen = 70; memcpy(buf+8, pktin.body+4, strlen); buf[8+strlen] = '\0'; logevent(buf); goto next_packet; } else if (pktin.type == SSH1_MSG_IGNORE) { /* do nothing */ goto next_packet; } crFinish(0); } static int ssh2_rdpkt(unsigned char **data, int *datalen) { struct rdpkt2_state_tag *st = &rdpkt2_state; crBegin; next_packet: pktin.type = 0; pktin.length = 0; if (sccipher) st->cipherblk = sccipher->blksize; else st->cipherblk = 8; if (st->cipherblk < 8) st->cipherblk = 8; if (pktin.maxlen < st->cipherblk) { pktin.maxlen = st->cipherblk; pktin.data = (pktin.data == NULL ? smalloc(st->cipherblk+APIEXTRA) : srealloc(pktin.data, st->cipherblk+APIEXTRA)); if (!pktin.data) fatalbox("Out of memory"); } /* * 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(st->cipherblk-st->i); pktin.data[st->i] = *(*data)++; (*datalen)--; } #ifdef FWHACK if (!memcmp(pktin.data, "Remo", 4)) {/* "Remo"te server has closed ... */ /* FIXME */ } #endif if (sccipher) sccipher->decrypt(pktin.data, st->cipherblk); /* * Now get the length and padding figures. */ st->len = GET_32BIT(pktin.data); st->pad = pktin.data[4]; /* * This enables us to deduce the payload length. */ st->payload = st->len - st->pad - 1; pktin.length = st->payload + 5; /* * So now we can work out the total packet length. */ st->packetlen = st->len + 4; st->maclen = scmac ? scmac->len : 0; /* * Adjust memory allocation if packet is too big. */ if (pktin.maxlen < st->packetlen+st->maclen) { pktin.maxlen = st->packetlen+st->maclen; pktin.data = (pktin.data == NULL ? smalloc(pktin.maxlen+APIEXTRA) : srealloc(pktin.data, pktin.maxlen+APIEXTRA)); if (!pktin.data) fatalbox("Out of memory"); } /* * 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(st->packetlen + st->maclen - st->i); pktin.data[st->i] = *(*data)++; (*datalen)--; } /* Decrypt everything _except_ the MAC. */ if (sccipher) sccipher->decrypt(pktin.data + st->cipherblk, st->packetlen - st->cipherblk); #if 0 debug(("Got packet len=%d pad=%d\r\n", st->len, st->pad)); for (st->i = 0; st->i < st->packetlen; st->i++) debug((" %02x", (unsigned char)pktin.data[st->i])); debug(("\r\n")); #endif /* * Check the MAC. */ if (scmac && !scmac->verify(pktin.data, st->len+4, st->incoming_sequence)) { bombout(("Incorrect MAC received on packet")); crReturn(0); } st->incoming_sequence++; /* whether or not we MACed */ /* * Decompress packet payload. */ { unsigned char *newpayload; int newlen; if (sccomp && sccomp->decompress(pktin.data+5, pktin.length-5, &newpayload, &newlen)) { if (pktin.maxlen < newlen+5) { pktin.maxlen = newlen+5; pktin.data = (pktin.data == NULL ? smalloc(pktin.maxlen+APIEXTRA) : srealloc(pktin.data, pktin.maxlen+APIEXTRA)); if (!pktin.data) fatalbox("Out of memory"); } pktin.length = 5 + newlen; memcpy(pktin.data+5, newpayload, newlen); #if 0 debug(("Post-decompression payload:\r\n")); for (st->i = 0; st->i < newlen; st->i++) debug((" %02x", (unsigned char)pktin.data[5+st->i])); debug(("\r\n")); #endif sfree(newpayload); } } pktin.savedpos = 6; pktin.type = pktin.data[5]; if (pktin.type == SSH2_MSG_IGNORE || pktin.type == SSH2_MSG_DEBUG) goto next_packet; /* FIXME: print DEBUG message */ crFinish(0); } static void ssh1_pktout_size(int len) { int pad, biglen; len += 5; /* type and CRC */ pad = 8 - (len%8); biglen = len + pad; pktout.length = len-5; if (pktout.maxlen < biglen) { pktout.maxlen = biglen; #ifdef MSCRYPTOAPI /* Allocate enough buffer space for extra block * for MS CryptEncrypt() */ pktout.data = (pktout.data == NULL ? smalloc(biglen+12) : srealloc(pktout.data, biglen+12)); #else pktout.data = (pktout.data == NULL ? smalloc(biglen+4) : srealloc(pktout.data, biglen+4)); #endif if (!pktout.data) fatalbox("Out of memory"); } pktout.body = pktout.data+4+pad+1; } static void s_wrpkt_start(int type, int len) { ssh1_pktout_size(len); pktout.type = type; } static int s_wrpkt_prepare(void) { int pad, len, biglen, i; unsigned long crc; pktout.body[-1] = pktout.type; #if 0 debug(("Packet payload pre-compression:\n")); for (i = -1; i < pktout.length; i++) debug((" %02x", (unsigned char)pktout.body[i])); debug(("\r\n")); #endif if (ssh1_compressing) { unsigned char *compblk; int complen; zlib_compress_block(pktout.body-1, pktout.length+1, &compblk, &complen); ssh1_pktout_size(complen-1); memcpy(pktout.body-1, compblk, complen); sfree(compblk); #if 0 debug(("Packet payload post-compression:\n")); for (i = -1; i < pktout.length; i++) debug((" %02x", (unsigned char)pktout.body[i])); debug(("\r\n")); #endif } len = pktout.length + 5; /* type and CRC */ pad = 8 - (len%8); biglen = len + pad; for (i=0; iencrypt(pktout.data+4, biglen); return biglen+4; } static void s_wrpkt(void) { int len; len = s_wrpkt_prepare(); sk_write(s, pktout.data, len); } static void s_wrpkt_defer(void) { int len; len = s_wrpkt_prepare(); if (deferred_len + len > deferred_size) { deferred_size = deferred_len + len + 128; deferred_send_data = srealloc(deferred_send_data, deferred_size); } memcpy(deferred_send_data+deferred_len, pktout.data, len); deferred_len += len; } /* * Construct a packet with the specified contents. */ static void construct_packet(int pkttype, va_list ap1, va_list ap2) { unsigned char *p, *argp, argchar; unsigned long argint; int pktlen, argtype, arglen; Bignum bn; 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, char); 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(argp); pktlen += 4 + arglen; break; case PKT_BIGNUM: bn = va_arg(ap1, Bignum); pktlen += ssh1_bignum_length(bn); break; default: assert(0); } } s_wrpkt_start(pkttype, pktlen); p = pktout.body; while ((argtype = va_arg(ap2, int)) != PKT_END) { switch (argtype) { case PKT_INT: argint = va_arg(ap2, int); PUT_32BIT(p, argint); p += 4; break; case PKT_CHAR: argchar = va_arg(ap2, unsigned char); *p = argchar; p++; break; case PKT_DATA: argp = va_arg(ap2, unsigned char *); arglen = va_arg(ap2, int); memcpy(p, argp, arglen); p += arglen; break; case PKT_STR: argp = va_arg(ap2, unsigned char *); arglen = strlen(argp); PUT_32BIT(p, arglen); memcpy(p + 4, argp, arglen); p += 4 + arglen; break; case PKT_BIGNUM: bn = va_arg(ap2, Bignum); p += ssh1_write_bignum(p, bn); break; } } } static void send_packet(int pkttype, ...) { va_list ap1, ap2; va_start(ap1, pkttype); va_start(ap2, pkttype); construct_packet(pkttype, ap1, ap2); s_wrpkt(); } static void defer_packet(int pkttype, ...) { va_list ap1, ap2; va_start(ap1, pkttype); va_start(ap2, pkttype); construct_packet(pkttype, ap1, ap2); s_wrpkt_defer(); } 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); } /* * SSH2 packet construction functions. */ static void ssh2_pkt_ensure(int length) { if (pktout.maxlen < length) { pktout.maxlen = length + 256; pktout.data = (pktout.data == NULL ? smalloc(pktout.maxlen+APIEXTRA) : srealloc(pktout.data, pktout.maxlen+APIEXTRA)); if (!pktout.data) fatalbox("Out of memory"); } } static void ssh2_pkt_adddata(void *data, int len) { pktout.length += len; ssh2_pkt_ensure(pktout.length); memcpy(pktout.data+pktout.length-len, data, len); } static void ssh2_pkt_addbyte(unsigned char byte) { ssh2_pkt_adddata(&byte, 1); } static void ssh2_pkt_init(int pkt_type) { pktout.length = 5; ssh2_pkt_addbyte((unsigned char)pkt_type); } static void ssh2_pkt_addbool(unsigned char value) { ssh2_pkt_adddata(&value, 1); } static void ssh2_pkt_adduint32(unsigned long value) { unsigned char x[4]; PUT_32BIT(x, value); ssh2_pkt_adddata(x, 4); } static void ssh2_pkt_addstring_start(void) { ssh2_pkt_adduint32(0); pktout.savedpos = pktout.length; } static void ssh2_pkt_addstring_str(char *data) { ssh2_pkt_adddata(data, strlen(data)); PUT_32BIT(pktout.data + pktout.savedpos - 4, pktout.length - pktout.savedpos); } static void ssh2_pkt_addstring_data(char *data, int len) { ssh2_pkt_adddata(data, len); PUT_32BIT(pktout.data + pktout.savedpos - 4, pktout.length - pktout.savedpos); } static void ssh2_pkt_addstring(char *data) { ssh2_pkt_addstring_start(); ssh2_pkt_addstring_str(data); } static char *ssh2_mpint_fmt(Bignum b, int *len) { unsigned char *p; int i, n = (ssh1_bignum_bitcount(b)+7)/8; p = smalloc(n + 1); 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(Bignum b) { unsigned char *p; int len; p = ssh2_mpint_fmt(b, &len); ssh2_pkt_addstring_start(); ssh2_pkt_addstring_data(p, len); sfree(p); } /* * Construct an SSH2 final-form packet: compress it, encrypt it, * put the MAC on it. Final packet, ready to be sent, is stored in * pktout.data. Total length is returned. */ static int ssh2_pkt_construct(void) { int cipherblk, maclen, padding, i; static unsigned long outgoing_sequence = 0; /* * Compress packet payload. */ #if 0 debug(("Pre-compression payload:\r\n")); for (i = 5; i < pktout.length; i++) debug((" %02x", (unsigned char)pktout.data[i])); debug(("\r\n")); #endif { unsigned char *newpayload; int newlen; if (cscomp && cscomp->compress(pktout.data+5, pktout.length-5, &newpayload, &newlen)) { pktout.length = 5; ssh2_pkt_adddata(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. */ cipherblk = cscipher ? cscipher->blksize : 8; /* block size */ cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */ padding = 4; padding += (cipherblk - (pktout.length + padding) % cipherblk) % cipherblk; maclen = csmac ? csmac->len : 0; ssh2_pkt_ensure(pktout.length + padding + maclen); pktout.data[4] = padding; for (i = 0; i < padding; i++) pktout.data[pktout.length + i] = random_byte(); PUT_32BIT(pktout.data, pktout.length + padding - 4); if (csmac) csmac->generate(pktout.data, pktout.length + padding, outgoing_sequence); outgoing_sequence++; /* whether or not we MACed */ #if 0 debug(("Sending packet len=%d\r\n", pktout.length+padding)); for (i = 0; i < pktout.length+padding; i++) debug((" %02x", (unsigned char)pktout.data[i])); debug(("\r\n")); #endif if (cscipher) cscipher->encrypt(pktout.data, pktout.length + padding); /* Ready-to-send packet starts at pktout.data. We return length. */ return pktout.length + padding + maclen; } /* * Construct and send an SSH2 packet immediately. */ static void ssh2_pkt_send(void) { int len = ssh2_pkt_construct(); sk_write(s, pktout.data, len); } /* * Construct an SSH2 packet and add it to a deferred data block. * Useful for sending multiple packets in a single sk_write() call, * to prevent a traffic-analysing listener from being able to work * out the length of any particular packet (such as the password * packet). * * Note that because SSH2 sequence-numbers its packets, this can * NOT be used as an m4-style `defer' allowing packets to be * constructed in one order and sent in another. */ static void ssh2_pkt_defer(void) { int len = ssh2_pkt_construct(); if (deferred_len + len > deferred_size) { deferred_size = deferred_len + len + 128; deferred_send_data = srealloc(deferred_send_data, deferred_size); } memcpy(deferred_send_data+deferred_len, pktout.data, len); deferred_len += len; } /* * Send the whole deferred data block constructed by * ssh2_pkt_defer() or SSH1's defer_packet(). */ static void ssh_pkt_defersend(void) { sk_write(s, deferred_send_data, deferred_len); deferred_len = deferred_size = 0; sfree(deferred_send_data); deferred_send_data = NULL; } #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(("\r\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); } /* * SSH2 packet decode functions. */ static unsigned long ssh2_pkt_getuint32(void) { unsigned long value; if (pktin.length - pktin.savedpos < 4) return 0; /* arrgh, no way to decline (FIXME?) */ value = GET_32BIT(pktin.data+pktin.savedpos); pktin.savedpos += 4; return value; } static int ssh2_pkt_getbool(void) { unsigned long value; if (pktin.length - pktin.savedpos < 1) return 0; /* arrgh, no way to decline (FIXME?) */ value = pktin.data[pktin.savedpos] != 0; pktin.savedpos++; return value; } static void ssh2_pkt_getstring(char **p, int *length) { *p = NULL; if (pktin.length - pktin.savedpos < 4) return; *length = GET_32BIT(pktin.data+pktin.savedpos); pktin.savedpos += 4; if (pktin.length - pktin.savedpos < *length) return; *p = pktin.data+pktin.savedpos; pktin.savedpos += *length; } static Bignum ssh2_pkt_getmp(void) { char *p; int length; Bignum b; ssh2_pkt_getstring(&p, &length); if (!p) return NULL; if (p[0] & 0x80) { bombout(("internal error: Can't handle negative mpints")); return NULL; } b = bignum_from_bytes(p, length); return b; } /* * Examine the remote side's version string and compare it against * a list of known buggy implementations. */ static void ssh_detect_bugs(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 (!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")) { /* * 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 SSH1 ignore bug"); } if (!strncmp(imp, "2.1.0", 5) || !strncmp(imp, "2.0.", 4) || !strncmp(imp, "2.2.0", 5) || !strncmp(imp, "2.3.0", 5) || !strncmp(imp, "2.1 ", 4)) { /* * These versions have the HMAC bug. */ ssh_remote_bugs |= BUG_SSH2_HMAC; logevent("We believe remote version has SSH2 HMAC bug"); } } static int do_ssh_init(unsigned char c) { static char vslen; static char version[10]; static char *vstring; static int vstrsize; static char *vlog; static int i; crBegin; /* Search for the string "SSH-" in the input. */ 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') i = transS[i]; else if (c == 'H') i = transH[i]; else if (c == '-') i = transminus[i]; else i = 0; if (i < 0) break; crReturn(1); /* get another character */ } vstring = smalloc(16); vstrsize = 16; strcpy(vstring, "SSH-"); vslen = 4; i = 0; while (1) { crReturn(1); /* get another char */ if (vslen >= vstrsize-1) { vstrsize += 16; vstring = srealloc(vstring, vstrsize); } vstring[vslen++] = c; if (i >= 0) { if (c == '-') { version[i] = '\0'; i = -1; } else if (i < sizeof(version)-1) version[i++] = c; } else if (c == '\n') break; } ssh_agentfwd_enabled = FALSE; rdpkt2_state.incoming_sequence = 0; vstring[vslen] = 0; vlog = smalloc(20 + vslen); sprintf(vlog, "Server version: %s", vstring); ssh_detect_bugs(vstring); vlog[strcspn(vlog, "\r\n")] = '\0'; logevent(vlog); sfree(vlog); /* * Server version "1.99" means we can choose whether we use v1 * or v2 protocol. Choice is based on cfg.sshprot. */ if (ssh_versioncmp(version, cfg.sshprot == 1 ? "2.0" : "1.99") >= 0) { /* * This is a v2 server. Begin v2 protocol. */ char verstring[80], vlog[100]; sprintf(verstring, "SSH-2.0-%s", sshver); SHA_Init(&exhashbase); /* * Hash our version string and their version string. */ sha_string(&exhashbase, verstring, strlen(verstring)); sha_string(&exhashbase, vstring, strcspn(vstring, "\r\n")); sprintf(vlog, "We claim version: %s", verstring); logevent(vlog); strcat(verstring, "\n"); logevent("Using SSH protocol version 2"); sk_write(s, verstring, strlen(verstring)); ssh_protocol = ssh2_protocol; ssh_version = 2; s_rdpkt = ssh2_rdpkt; } else { /* * This is a v1 server. Begin v1 protocol. */ char verstring[80], vlog[100]; sprintf(verstring, "SSH-%s-%s", (ssh_versioncmp(version, "1.5") <= 0 ? version : "1.5"), sshver); sprintf(vlog, "We claim version: %s", verstring); logevent(vlog); strcat(verstring, "\n"); logevent("Using SSH protocol version 1"); sk_write(s, verstring, strlen(verstring)); ssh_protocol = ssh1_protocol; ssh_version = 1; s_rdpkt = ssh1_rdpkt; } ssh_state = SSH_STATE_BEFORE_SIZE; sfree(vstring); crFinish(0); } static void ssh_gotdata(unsigned char *data, int datalen) { crBegin; /* * 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; if (datalen == 0) crReturnV; /* more data please */ ret = do_ssh_init(*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; while (1) { while (datalen > 0) { if ( s_rdpkt(&data, &datalen) == 0 ) { ssh_protocol(NULL, 0, 1); if (ssh_state == SSH_STATE_CLOSED) { return; } } } crReturnV; } crFinishV; } static int ssh_closing (Plug plug, char *error_msg, int error_code, int calling_back) { ssh_state = SSH_STATE_CLOSED; sk_close(s); s = NULL; if (error_msg) { /* A socket error has occurred. */ connection_fatal (error_msg); } else { /* Otherwise, the remote side closed the connection normally. */ } return 0; } static int ssh_receive(Plug plug, int urgent, char *data, int len) { ssh_gotdata (data, len); if (ssh_state == SSH_STATE_CLOSED) { if (s) { sk_close(s); s = NULL; } return 0; } return 1; } /* * Connect to specified host and port. * Returns an error message, or NULL on success. * Also places the canonical host name into `realhost'. */ static char *connect_to_host(char *host, int port, char **realhost) { static struct plug_function_table fn_table = { ssh_closing, ssh_receive }, *fn_table_ptr = &fn_table; SockAddr addr; char *err; #ifdef FWHACK char *FWhost; int FWport; #endif savedhost = smalloc(1+strlen(host)); if (!savedhost) fatalbox("Out of memory"); strcpy(savedhost, host); if (port < 0) port = 22; /* default ssh port */ savedport = port; #ifdef FWHACK FWhost = host; FWport = port; host = FWSTR; port = 23; #endif /* * Try to find host. */ addr = sk_namelookup(host, realhost); if ( (err = sk_addr_error(addr)) ) return err; #ifdef FWHACK *realhost = FWhost; #endif /* * Open socket. */ s = sk_new(addr, port, 0, 1, &fn_table_ptr); if ( (err = sk_socket_error(s)) ) return err; #ifdef FWHACK sk_write(s, "connect ", 8); sk_write(s, FWhost, strlen(FWhost)); { char buf[20]; sprintf(buf, " %d\n", FWport); sk_write(s, buf, strlen(buf)); } #endif return NULL; } /* * Handle the key exchange and user authentication phases. */ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) { int i, j, len; unsigned char *rsabuf, *keystr1, *keystr2; unsigned char cookie[8]; struct RSAKey servkey, hostkey; struct MD5Context md5c; static unsigned long supported_ciphers_mask, supported_auths_mask; static int tried_publickey; static unsigned char session_id[16]; int cipher_type; static char username[100]; crBegin; if (!ispkt) crWaitUntil(ispkt); if (pktin.type != SSH1_SMSG_PUBLIC_KEY) { bombout(("Public key packet not received")); crReturn(0); } logevent("Received public keys"); memcpy(cookie, pktin.body, 8); i = makekey(pktin.body+8, &servkey, &keystr1, 0); j = makekey(pktin.body+8+i, &hostkey, &keystr2, 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); } ssh1_remote_protoflags = GET_32BIT(pktin.body+8+i+j); supported_ciphers_mask = GET_32BIT(pktin.body+12+i+j); supported_auths_mask = GET_32BIT(pktin.body+16+i+j); ssh1_local_protoflags = ssh1_remote_protoflags & SSH1_PROTOFLAGS_SUPPORTED; ssh1_local_protoflags |= SSH1_PROTOFLAG_SCREEN_NUMBER; MD5Init(&md5c); MD5Update(&md5c, keystr2, hostkey.bytes); MD5Update(&md5c, keystr1, servkey.bytes); MD5Update(&md5c, pktin.body, 8); MD5Final(session_id, &md5c); for (i=0; i<32; i++) session_key[i] = random_byte(); len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes); rsabuf = smalloc(len); if (!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 = smalloc(len); if (!keystr) fatalbox("Out of memory"); rsastr_fmt(keystr, &hostkey); rsa_fingerprint(fingerprint, sizeof(fingerprint), &hostkey); verify_ssh_host_key(savedhost, savedport, "rsa", keystr, fingerprint); sfree(keystr); } for (i=0; i<32; i++) { rsabuf[i] = session_key[i]; if (i < 16) rsabuf[i] ^= session_id[i]; } if (hostkey.bytes > servkey.bytes) { rsaencrypt(rsabuf, 32, &servkey); rsaencrypt(rsabuf, servkey.bytes, &hostkey); } else { rsaencrypt(rsabuf, 32, &hostkey); rsaencrypt(rsabuf, hostkey.bytes, &servkey); } logevent("Encrypted session key"); switch (cfg.cipher) { case CIPHER_BLOWFISH: cipher_type = SSH_CIPHER_BLOWFISH; break; case CIPHER_DES: cipher_type = SSH_CIPHER_DES; break; case CIPHER_3DES: cipher_type = SSH_CIPHER_3DES; break; case CIPHER_AES: c_write_str("AES not supported in SSH1, falling back to 3DES\r\n"); cipher_type = SSH_CIPHER_3DES; break; } if ((supported_ciphers_mask & (1 << cipher_type)) == 0) { c_write_str("Selected cipher not supported, falling back to 3DES\r\n"); cipher_type = SSH_CIPHER_3DES; } switch (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(SSH1_CMSG_SESSION_KEY, PKT_CHAR, cipher_type, PKT_DATA, cookie, 8, PKT_CHAR, (len*8) >> 8, PKT_CHAR, (len*8) & 0xFF, PKT_DATA, rsabuf, len, PKT_INT, ssh1_local_protoflags, PKT_END); logevent("Trying to enable encryption..."); sfree(rsabuf); cipher = cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 : cipher_type == SSH_CIPHER_DES ? &ssh_des : &ssh_3des; cipher->sesskey(session_key); crWaitUntil(ispkt); if (pktin.type != SSH1_SMSG_SUCCESS) { bombout(("Encryption not successfully enabled")); crReturn(0); } logevent("Successfully started encryption"); fflush(stdout); { static int pos = 0; static char c; if ((flags & FLAG_INTERACTIVE) && !*cfg.username) { if (ssh_get_line) { if (!ssh_get_line("login as: ", username, sizeof(username), FALSE)) { /* * get_line failed to get a username. * Terminate. */ logevent("No username provided. Abandoning session."); ssh_state = SSH_STATE_CLOSED; crReturn(1); } } else { c_write_str("login as: "); ssh_send_ok = 1; while (pos >= 0) { crWaitUntil(!ispkt); while (inlen--) switch (c = *in++) { case 10: case 13: username[pos] = 0; pos = -1; break; case 8: case 127: if (pos > 0) { c_write_str("\b \b"); pos--; } break; case 21: case 27: while (pos > 0) { c_write_str("\b \b"); pos--; } break; case 3: case 4: random_save_seed(); exit(0); break; default: if (((c >= ' ' && c <= '~') || ((unsigned char)c >= 160)) && pos < 40) { username[pos++] = c; c_write(&c, 1); } break; } } c_write_str("\r\n"); username[strcspn(username, "\n\r")] = '\0'; } } else { strncpy(username, cfg.username, 99); username[99] = '\0'; } send_packet(SSH1_CMSG_USER, PKT_STR, username, PKT_END); { char userlog[22+sizeof(username)]; sprintf(userlog, "Sent username \"%s\"", username); logevent(userlog); if (flags & FLAG_INTERACTIVE && (!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) { strcat(userlog, "\r\n"); c_write_str(userlog); } } } crWaitUntil(ispkt); tried_publickey = 0; while (pktin.type == SSH1_SMSG_FAILURE) { static char password[100]; static char prompt[200]; static int pos; static char c; static int pwpkt_type; /* * Show password prompt, having first obtained it via a TIS * or CryptoCard exchange if we're doing TIS or CryptoCard * authentication. */ pwpkt_type = SSH1_CMSG_AUTH_PASSWORD; if (agent_exists()) { /* * Attempt RSA authentication using Pageant. */ static unsigned char request[5], *response, *p; static int responselen; static int i, nkeys; static int authed = FALSE; void *r; logevent("Pageant is running. Requesting keys."); /* Request the keys held by the agent. */ PUT_32BIT(request, 1); request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES; agent_query(request, 5, &r, &responselen); response = (unsigned char *)r; if (response && responselen >= 5 && response[4] == SSH1_AGENT_RSA_IDENTITIES_ANSWER) { p = response + 5; nkeys = GET_32BIT(p); p += 4; { char buf[64]; sprintf(buf, "Pageant has %d SSH1 keys", nkeys); logevent(buf); } for (i = 0; i < nkeys; i++) { static struct RSAKey key; static Bignum challenge; static char *commentp; static int commentlen; { char buf[64]; sprintf(buf, "Trying Pageant key #%d", i); logevent(buf); } p += 4; p += ssh1_read_bignum(p, &key.exponent); p += ssh1_read_bignum(p, &key.modulus); commentlen = GET_32BIT(p); p += 4; commentp = p; p += commentlen; send_packet(SSH1_CMSG_AUTH_RSA, PKT_BIGNUM, key.modulus, PKT_END); crWaitUntil(ispkt); if (pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) { logevent("Key refused"); continue; } logevent("Received RSA challenge"); ssh1_read_bignum(pktin.body, &challenge); { char *agentreq, *q, *ret; int len, retlen; len = 1 + 4; /* message type, bit count */ len += ssh1_bignum_length(key.exponent); len += ssh1_bignum_length(key.modulus); len += ssh1_bignum_length(challenge); len += 16; /* session id */ len += 4; /* response format */ agentreq = smalloc(4 + len); PUT_32BIT(agentreq, len); q = agentreq + 4; *q++ = SSH1_AGENTC_RSA_CHALLENGE; PUT_32BIT(q, ssh1_bignum_bitcount(key.modulus)); q += 4; q += ssh1_write_bignum(q, key.exponent); q += ssh1_write_bignum(q, key.modulus); q += ssh1_write_bignum(q, challenge); memcpy(q, session_id, 16); q += 16; PUT_32BIT(q, 1); /* response format */ agent_query(agentreq, len+4, &ret, &retlen); sfree(agentreq); if (ret) { if (ret[4] == SSH1_AGENT_RSA_RESPONSE) { logevent("Sending Pageant's response"); send_packet(SSH1_CMSG_AUTH_RSA_RESPONSE, PKT_DATA, ret+5, 16, PKT_END); sfree(ret); crWaitUntil(ispkt); if (pktin.type == SSH1_SMSG_SUCCESS) { logevent("Pageant's response accepted"); if (flags & FLAG_VERBOSE) { c_write_str("Authenticated using RSA key \""); c_write(commentp, commentlen); c_write_str("\" from agent\r\n"); } 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(key.exponent); freebn(key.modulus); freebn(challenge); if (authed) break; } } if (authed) break; } if (*cfg.keyfile && !tried_publickey) pwpkt_type = SSH1_CMSG_AUTH_RSA; if (pktin.type == SSH1_SMSG_FAILURE && cfg.try_tis_auth && (supported_auths_mask & (1< sizeof(prompt)-1) challengelen = sizeof(prompt)-1; /* prevent overrun */ memcpy(prompt, pktin.body+4, challengelen); prompt[challengelen] = '\0'; } } if (pktin.type == SSH1_SMSG_FAILURE && cfg.try_tis_auth && (supported_auths_mask & (1< sizeof(prompt)-1) challengelen = sizeof(prompt)-1; /* prevent overrun */ memcpy(prompt, pktin.body+4, challengelen); strncpy(prompt + challengelen, "\r\nResponse : ", sizeof(prompt)-challengelen); prompt[sizeof(prompt)-1] = '\0'; } } if (pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) { sprintf(prompt, "%.90s@%.90s's password: ", username, savedhost); } if (pwpkt_type == SSH1_CMSG_AUTH_RSA) { char *comment = NULL; if (flags & FLAG_VERBOSE) c_write_str("Trying public key authentication.\r\n"); if (!rsakey_encrypted(cfg.keyfile, &comment)) { if (flags & FLAG_VERBOSE) c_write_str("No passphrase required.\r\n"); goto tryauth; } sprintf(prompt, "Passphrase for key \"%.100s\": ", comment); sfree(comment); } if (ssh_get_line) { if (!ssh_get_line(prompt, password, sizeof(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. */ logevent("No more passwords to try"); ssh_state = SSH_STATE_CLOSED; crReturn(1); } } else { c_write_str(prompt); pos = 0; ssh_send_ok = 1; while (pos >= 0) { crWaitUntil(!ispkt); while (inlen--) switch (c = *in++) { case 10: case 13: password[pos] = 0; pos = -1; break; case 8: case 127: if (pos > 0) pos--; break; case 21: case 27: pos = 0; break; case 3: case 4: random_save_seed(); exit(0); break; default: if (((c >= ' ' && c <= '~') || ((unsigned char)c >= 160)) && pos < sizeof(password)) password[pos++] = c; break; } } c_write_str("\r\n"); } tryauth: if (pwpkt_type == SSH1_CMSG_AUTH_RSA) { /* * Try public key authentication with the specified * key file. */ static struct RSAKey pubkey; static Bignum challenge, response; static int i; static unsigned char buffer[32]; tried_publickey = 1; i = loadrsakey(cfg.keyfile, &pubkey, password); if (i == 0) { c_write_str("Couldn't load public key from "); c_write_str(cfg.keyfile); c_write_str(".\r\n"); continue; /* go and try password */ } if (i == -1) { c_write_str("Wrong passphrase.\r\n"); tried_publickey = 0; continue; /* try again */ } /* * Send a public key attempt. */ send_packet(SSH1_CMSG_AUTH_RSA, PKT_BIGNUM, pubkey.modulus, PKT_END); crWaitUntil(ispkt); if (pktin.type == SSH1_SMSG_FAILURE) { c_write_str("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")); crReturn(0); } ssh1_read_bignum(pktin.body, &challenge); response = rsadecrypt(challenge, &pubkey); freebn(pubkey.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, session_id, 16); MD5Final(buffer, &md5c); send_packet(SSH1_CMSG_AUTH_RSA_RESPONSE, PKT_DATA, buffer, 16, PKT_END); crWaitUntil(ispkt); if (pktin.type == SSH1_SMSG_FAILURE) { if (flags & FLAG_VERBOSE) c_write_str("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")); crReturn(0); } break; /* we're through! */ } else { if (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. */ if (ssh_remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE) { char string[64]; char *s; int len; len = strlen(password); if (len < sizeof(string)) { s = string; strcpy(string, password); len++; /* cover the zero byte */ while (len < sizeof(string)) { string[len++] = (char)random_byte(); } } else { s = password; } send_packet(pwpkt_type, PKT_INT, len, PKT_DATA, s, len, PKT_END); } else { int bottom, top, pwlen, i; char *randomstr; pwlen = strlen(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 = smalloc(top+1); for (i = bottom; i <= top; i++) { if (i == pwlen) defer_packet(pwpkt_type, PKT_STR, password, PKT_END); else { for (j = 0; j < i; j++) { do { randomstr[j] = random_byte(); } while (randomstr[j] == '\0'); } randomstr[i] = '\0'; defer_packet(SSH1_MSG_IGNORE, PKT_STR, randomstr, PKT_END); } } ssh_pkt_defersend(); } } else { send_packet(pwpkt_type, PKT_STR, password, PKT_END); } } logevent("Sent password"); memset(password, 0, strlen(password)); crWaitUntil(ispkt); if (pktin.type == SSH1_SMSG_FAILURE) { if (flags & FLAG_VERBOSE) c_write_str("Access denied\r\n"); logevent("Authentication refused"); } else if (pktin.type == SSH1_MSG_DISCONNECT) { logevent("Received disconnect request"); ssh_state = SSH_STATE_CLOSED; crReturn(1); } else if (pktin.type != SSH1_SMSG_SUCCESS) { bombout(("Strange packet received, type %d", pktin.type)); crReturn(0); } } logevent("Authentication successful"); crFinish(1); } void sshfwd_close(struct ssh_channel *c) { if (c && !c->closes) { if (ssh_version == 1) { send_packet(SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid, PKT_END); } else { ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE); ssh2_pkt_adduint32(c->remoteid); ssh2_pkt_send(); } c->closes = 1; if (c->type == CHAN_X11) { c->u.x11.s = NULL; logevent("X11 connection terminated"); } } } void sshfwd_write(struct ssh_channel *c, char *buf, int len) { if (ssh_version == 1) { send_packet(SSH1_MSG_CHANNEL_DATA, PKT_INT, c->remoteid, PKT_INT, len, PKT_DATA, buf, len, PKT_END); } else { ssh2_add_channel_data(c, buf, len); ssh2_try_send(c); } } static void ssh1_protocol(unsigned char *in, int inlen, int ispkt) { crBegin; random_init(); while (!do_ssh1_login(in, inlen, ispkt)) { crReturnV; } if (ssh_state == SSH_STATE_CLOSED) crReturnV; if (cfg.agentfwd && agent_exists()) { logevent("Requesting agent forwarding"); send_packet(SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END); do { crReturnV; } while (!ispkt); if (pktin.type != SSH1_SMSG_SUCCESS && pktin.type != SSH1_SMSG_FAILURE) { bombout(("Protocol confusion")); crReturnV; } else if (pktin.type == SSH1_SMSG_FAILURE) { logevent("Agent forwarding refused"); } else { logevent("Agent forwarding enabled"); ssh_agentfwd_enabled = TRUE; } } if (cfg.x11_forward) { char proto[20], data[64]; logevent("Requesting X11 forwarding"); x11_invent_auth(proto, sizeof(proto), data, sizeof(data)); if (ssh1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) { send_packet(SSH1_CMSG_X11_REQUEST_FORWARDING, PKT_STR, proto, PKT_STR, data, PKT_INT, 0, PKT_END); } else { send_packet(SSH1_CMSG_X11_REQUEST_FORWARDING, PKT_STR, proto, PKT_STR, data, PKT_END); } do { crReturnV; } while (!ispkt); if (pktin.type != SSH1_SMSG_SUCCESS && pktin.type != SSH1_SMSG_FAILURE) { bombout(("Protocol confusion")); crReturnV; } else if (pktin.type == SSH1_SMSG_FAILURE) { logevent("X11 forwarding refused"); } else { logevent("X11 forwarding enabled"); ssh_X11_fwd_enabled = TRUE; } } if (!cfg.nopty) { send_packet(SSH1_CMSG_REQUEST_PTY, PKT_STR, cfg.termtype, PKT_INT, rows, PKT_INT, cols, PKT_INT, 0, PKT_INT, 0, PKT_CHAR, 0, PKT_END); ssh_state = SSH_STATE_INTERMED; do { crReturnV; } while (!ispkt); if (pktin.type != SSH1_SMSG_SUCCESS && pktin.type != SSH1_SMSG_FAILURE) { bombout(("Protocol confusion")); crReturnV; } else if (pktin.type == SSH1_SMSG_FAILURE) { c_write_str("Server refused to allocate pty\r\n"); ssh_editing = ssh_echoing = 1; } logevent("Allocated pty"); } else { ssh_editing = ssh_echoing = 1; } if (cfg.compression) { send_packet(SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END); do { crReturnV; } while (!ispkt); if (pktin.type != SSH1_SMSG_SUCCESS && pktin.type != SSH1_SMSG_FAILURE) { bombout(("Protocol confusion")); crReturnV; } else if (pktin.type == SSH1_SMSG_FAILURE) { c_write_str("Server refused to compress\r\n"); } logevent("Started compression"); ssh1_compressing = TRUE; zlib_compress_init(); zlib_decompress_init(); } if (*cfg.remote_cmd_ptr) send_packet(SSH1_CMSG_EXEC_CMD, PKT_STR, cfg.remote_cmd_ptr, PKT_END); else send_packet(SSH1_CMSG_EXEC_SHELL, PKT_END); logevent("Started session"); ssh_state = SSH_STATE_SESSION; if (size_needed) ssh_size(); if (eof_needed) ssh_special(TS_EOF); ldisc_send(NULL, 0); /* cause ldisc to notice changes */ ssh_send_ok = 1; ssh_channels = newtree234(ssh_channelcmp); while (1) { crReturnV; if (ispkt) { if (pktin.type == SSH1_SMSG_STDOUT_DATA || pktin.type == SSH1_SMSG_STDERR_DATA) { long len = GET_32BIT(pktin.body); from_backend(pktin.type == SSH1_SMSG_STDERR_DATA, pktin.body+4, len); } else if (pktin.type == SSH1_MSG_DISCONNECT) { ssh_state = SSH_STATE_CLOSED; logevent("Received disconnect request"); crReturnV; } else if (pktin.type == SSH1_SMSG_X11_OPEN) { /* Remote side is trying to open a channel to talk to our * X-Server. Give them back a local channel number. */ unsigned i; struct ssh_channel *c, *d; enum234 e; logevent("Received X11 connect request"); /* Refuse if X11 forwarding is disabled. */ if (!ssh_X11_fwd_enabled) { send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE, PKT_INT, GET_32BIT(pktin.body), PKT_END); logevent("Rejected X11 connect request"); } else { c = smalloc(sizeof(struct ssh_channel)); if ( x11_init(&c->u.x11.s, cfg.x11_display, c) != NULL ) { logevent("opening X11 forward connection failed"); sfree(c); send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE, PKT_INT, GET_32BIT(pktin.body), PKT_END); } else { logevent("opening X11 forward connection succeeded"); for (i=1, d = first234(ssh_channels, &e); d; d = next234(&e)) { if (d->localid > i) break; /* found a free number */ i = d->localid + 1; } c->remoteid = GET_32BIT(pktin.body); c->localid = i; c->closes = 0; c->type = CHAN_X11; /* identify channel type */ add234(ssh_channels, c); send_packet(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION, PKT_INT, c->remoteid, PKT_INT, c->localid, PKT_END); logevent("Opened X11 forward channel"); } } } else if (pktin.type == SSH1_SMSG_AGENT_OPEN) { /* Remote side is trying to open a channel to talk to our * agent. Give them back a local channel number. */ unsigned i; struct ssh_channel *c; enum234 e; /* Refuse if agent forwarding is disabled. */ if (!ssh_agentfwd_enabled) { send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE, PKT_INT, GET_32BIT(pktin.body), PKT_END); } else { i = 1; for (c = first234(ssh_channels, &e); c; c = next234(&e)) { if (c->localid > i) break; /* found a free number */ i = c->localid + 1; } c = smalloc(sizeof(struct ssh_channel)); c->remoteid = GET_32BIT(pktin.body); c->localid = i; c->closes = 0; c->type = CHAN_AGENT; /* identify channel type */ c->u.a.lensofar = 0; add234(ssh_channels, c); send_packet(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION, PKT_INT, c->remoteid, PKT_INT, c->localid, PKT_END); } } else if (pktin.type == SSH1_MSG_CHANNEL_CLOSE || pktin.type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION) { /* Remote side closes a channel. */ unsigned i = GET_32BIT(pktin.body); struct ssh_channel *c; c = find234(ssh_channels, &i, ssh_channelfind); if (c) { int closetype; closetype = (pktin.type == SSH1_MSG_CHANNEL_CLOSE ? 1 : 2); if (!(c->closes & closetype)) send_packet(pktin.type, PKT_INT, c->remoteid, PKT_END); if ((c->closes == 0) && (c->type == CHAN_X11)) { logevent("X11 connection closed"); assert(c->u.x11.s != NULL); x11_close(c->u.x11.s); c->u.x11.s = NULL; } c->closes |= closetype; if (c->closes == 3) { del234(ssh_channels, c); sfree(c); } } } else if (pktin.type == SSH1_MSG_CHANNEL_DATA) { /* Data sent down one of our channels. */ int i = GET_32BIT(pktin.body); int len = GET_32BIT(pktin.body+4); unsigned char *p = pktin.body+8; struct ssh_channel *c; c = find234(ssh_channels, &i, ssh_channelfind); if (c) { switch(c->type) { case CHAN_X11: x11_send(c->u.x11.s, p, len); break; case CHAN_AGENT: /* Data for an agent message. Buffer it. */ while (len > 0) { if (c->u.a.lensofar < 4) { 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 = smalloc(c->u.a.totallen); memcpy(c->u.a.message, c->u.a.msglen, 4); } if (c->u.a.lensofar >= 4 && len > 0) { 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, *sentreply; int replylen; agent_query(c->u.a.message, c->u.a.totallen, &reply, &replylen); if (reply) sentreply = reply; else { /* Fake SSH_AGENT_FAILURE. */ sentreply = "\0\0\0\1\5"; replylen = 5; } send_packet(SSH1_MSG_CHANNEL_DATA, PKT_INT, c->remoteid, PKT_INT, replylen, PKT_DATA, sentreply, replylen, PKT_END); if (reply) sfree(reply); sfree(c->u.a.message); c->u.a.lensofar = 0; } } break; } } } else 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 if (pktin.type == SSH1_SMSG_EXIT_STATUS) { send_packet(SSH1_CMSG_EXIT_CONFIRMATION, PKT_END); } else { bombout(("Strange packet received: type %d", pktin.type)); crReturnV; } } else { while (inlen > 0) { int len = min(inlen, 512); send_packet(SSH1_CMSG_STDIN_DATA, PKT_INT, len, PKT_DATA, in, len, PKT_END); in += len; inlen -= len; } } } crFinishV; } /* * Utility routine for decoding comma-separated strings in KEXINIT. */ static int in_commasep_string(char *needle, char *haystack, int haylen) { int 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 */ } } /* * SSH2 key creation method. */ static void ssh2_mkkey(Bignum K, char *H, char *sessid, char chr, char *keyspace) { SHA_State s; /* First 20 bytes. */ SHA_Init(&s); 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); sha_mpint(&s, K); SHA_Bytes(&s, H, 20); SHA_Bytes(&s, keyspace, 20); SHA_Final(&s, keyspace+20); } /* * Handle the SSH2 transport layer. */ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt) { static int i, j, len, nbits, pbits; static char *str; static Bignum p, g, e, f, K; static int kex_init_value, kex_reply_value; static const struct ssh_mac **maclist; static int nmacs; static const struct ssh2_cipher *cscipher_tobe = NULL; static const struct ssh2_cipher *sccipher_tobe = NULL; static const struct ssh_mac *csmac_tobe = NULL; static const struct ssh_mac *scmac_tobe = NULL; static const struct ssh_compress *cscomp_tobe = NULL; static const struct ssh_compress *sccomp_tobe = NULL; static char *hostkeydata, *sigdata, *keystr, *fingerprint; static int hostkeylen, siglen; static void *hkey; /* actual host key */ static unsigned char exchange_hash[20]; static unsigned char keyspace[40]; static const struct ssh2_ciphers *preferred_cipher; static const struct ssh_compress *preferred_comp; static int first_kex; crBegin; random_init(); first_kex = 1; /* * Set up the preferred cipher and compression. */ if (cfg.cipher == CIPHER_BLOWFISH) { preferred_cipher = &ssh2_blowfish; } else if (cfg.cipher == CIPHER_DES) { logevent("Single DES not supported in SSH2; using 3DES"); preferred_cipher = &ssh2_3des; } else if (cfg.cipher == CIPHER_3DES) { preferred_cipher = &ssh2_3des; } else if (cfg.cipher == CIPHER_AES) { preferred_cipher = &ssh2_aes; } else { /* Shouldn't happen, but we do want to initialise to _something_. */ preferred_cipher = &ssh2_3des; } if (cfg.compression) preferred_comp = &ssh_zlib; else preferred_comp = &ssh_comp_none; /* * Be prepared to work around the buggy MAC problem. */ if (cfg.buggymac || (ssh_remote_bugs & BUG_SSH2_HMAC)) maclist = buggymacs, nmacs = lenof(buggymacs); else maclist = macs, nmacs = lenof(macs); begin_key_exchange: /* * Construct and send our key exchange packet. */ ssh2_pkt_init(SSH2_MSG_KEXINIT); for (i = 0; i < 16; i++) ssh2_pkt_addbyte((unsigned char)random_byte()); /* List key exchange algorithms. */ ssh2_pkt_addstring_start(); for (i = 0; i < lenof(kex_algs); i++) { ssh2_pkt_addstring_str(kex_algs[i]->name); if (i < lenof(kex_algs)-1) ssh2_pkt_addstring_str(","); } /* List server host key algorithms. */ ssh2_pkt_addstring_start(); for (i = 0; i < lenof(hostkey_algs); i++) { ssh2_pkt_addstring_str(hostkey_algs[i]->name); if (i < lenof(hostkey_algs)-1) ssh2_pkt_addstring_str(","); } /* List client->server encryption algorithms. */ ssh2_pkt_addstring_start(); for (i = 0; i < lenof(ciphers)+1; i++) { const struct ssh2_ciphers *c = i==0 ? preferred_cipher : ciphers[i-1]; for (j = 0; j < c->nciphers; j++) { ssh2_pkt_addstring_str(c->list[j]->name); if (i < lenof(ciphers) || j < c->nciphers-1) ssh2_pkt_addstring_str(","); } } /* List server->client encryption algorithms. */ ssh2_pkt_addstring_start(); for (i = 0; i < lenof(ciphers)+1; i++) { const struct ssh2_ciphers *c = i==0 ? preferred_cipher : ciphers[i-1]; for (j = 0; j < c->nciphers; j++) { ssh2_pkt_addstring_str(c->list[j]->name); if (i < lenof(ciphers) || j < c->nciphers-1) ssh2_pkt_addstring_str(","); } } /* List client->server MAC algorithms. */ ssh2_pkt_addstring_start(); for (i = 0; i < nmacs; i++) { ssh2_pkt_addstring_str(maclist[i]->name); if (i < nmacs-1) ssh2_pkt_addstring_str(","); } /* List server->client MAC algorithms. */ ssh2_pkt_addstring_start(); for (i = 0; i < nmacs; i++) { ssh2_pkt_addstring_str(maclist[i]->name); if (i < nmacs-1) ssh2_pkt_addstring_str(","); } /* List client->server compression algorithms. */ ssh2_pkt_addstring_start(); for (i = 0; i < lenof(compressions)+1; i++) { const struct ssh_compress *c = i==0 ? preferred_comp : compressions[i-1]; ssh2_pkt_addstring_str(c->name); if (i < lenof(compressions)) ssh2_pkt_addstring_str(","); } /* List server->client compression algorithms. */ ssh2_pkt_addstring_start(); for (i = 0; i < lenof(compressions)+1; i++) { const struct ssh_compress *c = i==0 ? preferred_comp : compressions[i-1]; ssh2_pkt_addstring_str(c->name); if (i < lenof(compressions)) ssh2_pkt_addstring_str(","); } /* List client->server languages. Empty list. */ ssh2_pkt_addstring_start(); /* List server->client languages. Empty list. */ ssh2_pkt_addstring_start(); /* First KEX packet does _not_ follow, because we're not that brave. */ ssh2_pkt_addbool(FALSE); /* Reserved. */ ssh2_pkt_adduint32(0); exhash = exhashbase; sha_string(&exhash, pktout.data+5, pktout.length-5); ssh2_pkt_send(); if (!ispkt) crWaitUntil(ispkt); sha_string(&exhash, pktin.data+5, pktin.length-5); /* * Now examine the other side's KEXINIT to see what we're up * to. */ if (pktin.type != SSH2_MSG_KEXINIT) { bombout(("expected key exchange packet from server")); crReturn(0); } kex = NULL; hostkey = NULL; cscipher_tobe = NULL; sccipher_tobe = NULL; csmac_tobe = NULL; scmac_tobe = NULL; cscomp_tobe = NULL; sccomp_tobe = NULL; pktin.savedpos += 16; /* skip garbage cookie */ ssh2_pkt_getstring(&str, &len); /* key exchange algorithms */ for (i = 0; i < lenof(kex_algs); i++) { if (in_commasep_string(kex_algs[i]->name, str, len)) { kex = kex_algs[i]; break; } } ssh2_pkt_getstring(&str, &len); /* host key algorithms */ for (i = 0; i < lenof(hostkey_algs); i++) { if (in_commasep_string(hostkey_algs[i]->name, str, len)) { hostkey = hostkey_algs[i]; break; } } ssh2_pkt_getstring(&str, &len); /* client->server cipher */ for (i = 0; i < lenof(ciphers)+1; i++) { const struct ssh2_ciphers *c = i==0 ? preferred_cipher : ciphers[i-1]; for (j = 0; j < c->nciphers; j++) { if (in_commasep_string(c->list[j]->name, str, len)) { cscipher_tobe = c->list[j]; break; } } if (cscipher_tobe) break; } ssh2_pkt_getstring(&str, &len); /* server->client cipher */ for (i = 0; i < lenof(ciphers)+1; i++) { const struct ssh2_ciphers *c = i==0 ? preferred_cipher : ciphers[i-1]; for (j = 0; j < c->nciphers; j++) { if (in_commasep_string(c->list[j]->name, str, len)) { sccipher_tobe = c->list[j]; break; } } if (sccipher_tobe) break; } ssh2_pkt_getstring(&str, &len); /* client->server mac */ for (i = 0; i < nmacs; i++) { if (in_commasep_string(maclist[i]->name, str, len)) { csmac_tobe = maclist[i]; break; } } ssh2_pkt_getstring(&str, &len); /* server->client mac */ for (i = 0; i < nmacs; i++) { if (in_commasep_string(maclist[i]->name, str, len)) { scmac_tobe = maclist[i]; break; } } ssh2_pkt_getstring(&str, &len); /* client->server compression */ for (i = 0; i < lenof(compressions)+1; i++) { const struct ssh_compress *c = i==0 ? preferred_comp : compressions[i-1]; if (in_commasep_string(c->name, str, len)) { cscomp_tobe = c; break; } } ssh2_pkt_getstring(&str, &len); /* server->client compression */ for (i = 0; i < lenof(compressions)+1; i++) { const struct ssh_compress *c = i==0 ? preferred_comp : compressions[i-1]; if (in_commasep_string(c->name, str, len)) { sccomp_tobe = c; break; } } /* * 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 = cscipher_tobe->keylen; scbits = sccipher_tobe->keylen; 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 (nbits > 160) nbits = 160; /* * If we're doing Diffie-Hellman group exchange, start by * requesting a group. */ if (kex == &ssh_diffiehellman_gex) { logevent("Doing Diffie-Hellman group exchange"); /* * Work out how big a DH group we will need to allow that * much data. */ pbits = 512 << ((nbits-1) / 64); ssh2_pkt_init(SSH2_MSG_KEX_DH_GEX_REQUEST); ssh2_pkt_adduint32(pbits); ssh2_pkt_send(); crWaitUntil(ispkt); if (pktin.type != SSH2_MSG_KEX_DH_GEX_GROUP) { bombout(("expected key exchange group packet from server")); crReturn(0); } p = ssh2_pkt_getmp(); g = ssh2_pkt_getmp(); dh_setup_group(p, g); kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT; kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY; } else { dh_setup_group1(); kex_init_value = SSH2_MSG_KEXDH_INIT; kex_reply_value = SSH2_MSG_KEXDH_REPLY; } logevent("Doing Diffie-Hellman key exchange"); /* * Now generate and send e for Diffie-Hellman. */ e = dh_create_e(nbits*2); ssh2_pkt_init(kex_init_value); ssh2_pkt_addmp(e); ssh2_pkt_send(); crWaitUntil(ispkt); if (pktin.type != kex_reply_value) { bombout(("expected key exchange reply packet from server")); crReturn(0); } ssh2_pkt_getstring(&hostkeydata, &hostkeylen); f = ssh2_pkt_getmp(); ssh2_pkt_getstring(&sigdata, &siglen); K = dh_find_K(f); sha_string(&exhash, hostkeydata, hostkeylen); if (kex == &ssh_diffiehellman_gex) { sha_uint32(&exhash, pbits); sha_mpint(&exhash, p); sha_mpint(&exhash, g); } sha_mpint(&exhash, e); sha_mpint(&exhash, f); sha_mpint(&exhash, K); SHA_Final(&exhash, exchange_hash); dh_cleanup(); #if 0 debug(("Exchange hash is:\r\n")); for (i = 0; i < 20; i++) debug((" %02x", exchange_hash[i])); debug(("\r\n")); #endif hkey = hostkey->newkey(hostkeydata, hostkeylen); if (!hostkey->verifysig(hkey, sigdata, siglen, exchange_hash, 20)) { bombout(("Server failed host key check")); crReturn(0); } /* * Expect SSH2_MSG_NEWKEYS from server. */ crWaitUntil(ispkt); if (pktin.type != SSH2_MSG_NEWKEYS) { bombout(("expected new-keys packet from server")); crReturn(0); } /* * Authenticate remote host: verify host key. (We've already * checked the signature of the exchange hash.) */ keystr = hostkey->fmtkey(hkey); fingerprint = hostkey->fingerprint(hkey); verify_ssh_host_key(savedhost, savedport, hostkey->keytype, keystr, fingerprint); if (first_kex) { /* don't bother logging this in rekeys */ logevent("Host key fingerprint is:"); logevent(fingerprint); } sfree(fingerprint); sfree(keystr); hostkey->freekey(hkey); /* * Send SSH2_MSG_NEWKEYS. */ ssh2_pkt_init(SSH2_MSG_NEWKEYS); ssh2_pkt_send(); /* * Create and initialise session keys. */ cscipher = cscipher_tobe; sccipher = sccipher_tobe; csmac = csmac_tobe; scmac = scmac_tobe; cscomp = cscomp_tobe; sccomp = sccomp_tobe; cscomp->compress_init(); sccomp->decompress_init(); /* * Set IVs after keys. Here we use the exchange hash from the * _first_ key exchange. */ if (first_kex) memcpy(ssh2_session_id, exchange_hash, sizeof(exchange_hash)); ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'C', keyspace); cscipher->setcskey(keyspace); ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'D', keyspace); sccipher->setsckey(keyspace); ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'A', keyspace); cscipher->setcsiv(keyspace); ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'B', keyspace); sccipher->setsciv(keyspace); ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'E', keyspace); csmac->setcskey(keyspace); ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'F', keyspace); scmac->setsckey(keyspace); /* * 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 (!first_kex) { crReturn(0); } first_kex = 0; /* * 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. */ while (!(ispkt && pktin.type == SSH2_MSG_KEXINIT)) { crReturn(1); } logevent("Server initiated key re-exchange"); goto begin_key_exchange; crFinish(1); } /* * Add data to an SSH2 channel output buffer. */ static void ssh2_add_channel_data(struct ssh_channel *c, char *buf, int len) { if (c->v2.outbufsize < c->v2.outbuflen + len) { c->v2.outbufsize = c->v2.outbuflen + len + 1024; c->v2.outbuffer = srealloc(c->v2.outbuffer, c->v2.outbufsize); } memcpy(c->v2.outbuffer + c->v2.outbuflen, buf, len); c->v2.outbuflen += len; } /* * Attempt to send data on an SSH2 channel. */ static void ssh2_try_send(struct ssh_channel *c) { while (c->v2.remwindow > 0 && c->v2.outbuflen > 0) { unsigned len = c->v2.remwindow; if (len > c->v2.outbuflen) len = c->v2.outbuflen; if (len > c->v2.remmaxpkt) len = c->v2.remmaxpkt; ssh2_pkt_init(SSH2_MSG_CHANNEL_DATA); ssh2_pkt_adduint32(c->remoteid); ssh2_pkt_addstring_start(); ssh2_pkt_addstring_data(c->v2.outbuffer, len); ssh2_pkt_send(); c->v2.outbuflen -= len; memmove(c->v2.outbuffer, c->v2.outbuffer+len, c->v2.outbuflen); c->v2.remwindow -= len; } } /* * Handle the SSH2 userauth and connection layers. */ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) { static unsigned long remote_winsize; static unsigned long remote_maxpkt; static enum { AUTH_INVALID, AUTH_PUBLICKEY_AGENT, AUTH_PUBLICKEY_FILE, AUTH_PASSWORD } method; static enum { AUTH_TYPE_NONE, AUTH_TYPE_PUBLICKEY, AUTH_TYPE_PUBLICKEY_OFFER_LOUD, AUTH_TYPE_PUBLICKEY_OFFER_QUIET, AUTH_TYPE_PASSWORD } type; static int gotit, need_pw, can_pubkey, can_passwd; static int tried_pubkey_config, tried_agent; static int we_are_in; static char username[100]; static char pwprompt[200]; static char password[100]; crBegin; /* * Request userauth protocol, and await a response to it. */ ssh2_pkt_init(SSH2_MSG_SERVICE_REQUEST); ssh2_pkt_addstring("ssh-userauth"); ssh2_pkt_send(); crWaitUntilV(ispkt); if (pktin.type != SSH2_MSG_SERVICE_ACCEPT) { bombout(("Server refused user authentication protocol")); crReturnV; } /* * We repeat this whole loop, including the username prompt, * until we manage a successful authentication. If the user * types the wrong _password_, they are sent back to the * beginning to try another username. (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! */ do { static int pos; static char c; /* * Get a username. */ pos = 0; if ((flags & FLAG_INTERACTIVE) && !*cfg.username) { if (ssh_get_line) { if (!ssh_get_line("login as: ", username, sizeof(username), FALSE)) { /* * get_line failed to get a username. * Terminate. */ logevent("No username provided. Abandoning session."); ssh_state = SSH_STATE_CLOSED; crReturnV; } } else { c_write_str("login as: "); ssh_send_ok = 1; while (pos >= 0) { crWaitUntilV(!ispkt); while (inlen--) switch (c = *in++) { case 10: case 13: username[pos] = 0; pos = -1; break; case 8: case 127: if (pos > 0) { c_write_str("\b \b"); pos--; } break; case 21: case 27: while (pos > 0) { c_write_str("\b \b"); pos--; } break; case 3: case 4: random_save_seed(); exit(0); break; default: if (((c >= ' ' && c <= '~') || ((unsigned char)c >= 160)) && pos < 40) { username[pos++] = c; c_write(&c, 1); } break; } } } c_write_str("\r\n"); username[strcspn(username, "\n\r")] = '\0'; } else { char stuff[200]; strncpy(username, cfg.username, 99); username[99] = '\0'; if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) { sprintf(stuff, "Using username \"%s\".\r\n", username); c_write_str(stuff); } } /* * 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. */ ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST); ssh2_pkt_addstring(username); ssh2_pkt_addstring("ssh-connection"); /* service requested */ ssh2_pkt_addstring("none"); /* method */ ssh2_pkt_send(); type = AUTH_TYPE_NONE; gotit = FALSE; we_are_in = FALSE; tried_pubkey_config = FALSE; tried_agent = FALSE; while (1) { /* * Wait for the result of the last authentication request. */ if (!gotit) crWaitUntilV(ispkt); 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)) { ssh2_pkt_getstring(&banner, &size); if (banner) c_write_untrusted(banner, size); } crWaitUntilV(ispkt); } if (pktin.type == SSH2_MSG_USERAUTH_SUCCESS) { logevent("Access granted"); we_are_in = TRUE; break; } if (pktin.type != SSH2_MSG_USERAUTH_FAILURE) { bombout(("Strange packet received during authentication: type %d", pktin.type)); } 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. */ { char *methods; int methlen; ssh2_pkt_getstring(&methods, &methlen); if (!ssh2_pkt_getbool()) { /* * 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. */ if (type == AUTH_TYPE_NONE) { /* do nothing */ } else if (type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD || type == AUTH_TYPE_PUBLICKEY_OFFER_QUIET) { if (type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD) c_write_str("Server refused our key\r\n"); logevent("Server refused public key"); } else { c_write_str("Access denied\r\n"); logevent("Access denied"); if (type == AUTH_TYPE_PASSWORD) { we_are_in = FALSE; break; } } } else { c_write_str("Further authentication required\r\n"); logevent("Further authentication required"); } can_pubkey = in_commasep_string("publickey", methods, methlen); can_passwd = in_commasep_string("password", methods, methlen); } method = 0; if (!method && can_pubkey && agent_exists && !tried_agent) { /* * Attempt public-key authentication using Pageant. */ static unsigned char request[5], *response, *p; static int responselen; static int i, nkeys; static int authed = FALSE; void *r; tried_agent = TRUE; logevent("Pageant is running. Requesting keys."); /* Request the keys held by the agent. */ PUT_32BIT(request, 1); request[4] = SSH2_AGENTC_REQUEST_IDENTITIES; agent_query(request, 5, &r, &responselen); response = (unsigned char *)r; if (response && responselen >= 5 && response[4] == SSH2_AGENT_IDENTITIES_ANSWER) { p = response + 5; nkeys = GET_32BIT(p); p += 4; { char buf[64]; sprintf(buf, "Pageant has %d SSH2 keys", nkeys); logevent(buf); } for (i = 0; i < nkeys; i++) { static char *pkblob, *alg, *commentp; static int pklen, alglen, commentlen; static int siglen, retlen, len; static char *q, *agentreq, *ret; { char buf[64]; sprintf(buf, "Trying Pageant key #%d", i); logevent(buf); } pklen = GET_32BIT(p); p += 4; pkblob = p; p += pklen; alglen = GET_32BIT(pkblob); alg = pkblob + 4; commentlen = GET_32BIT(p); p += 4; commentp = p; p += commentlen; ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST); ssh2_pkt_addstring(username); ssh2_pkt_addstring("ssh-connection");/* service requested */ ssh2_pkt_addstring("publickey");/* method */ ssh2_pkt_addbool(FALSE); /* no signature included */ ssh2_pkt_addstring_start(); ssh2_pkt_addstring_data(alg, alglen); ssh2_pkt_addstring_start(); ssh2_pkt_addstring_data(pkblob, pklen); ssh2_pkt_send(); crWaitUntilV(ispkt); if (pktin.type != SSH2_MSG_USERAUTH_PK_OK) { logevent("Key refused"); continue; } if (flags & FLAG_VERBOSE) { c_write_str("Authenticating with public key \""); c_write(commentp, commentlen); c_write_str("\" from agent\r\n"); } /* * Server is willing to accept the key. * Construct a SIGN_REQUEST. */ ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST); ssh2_pkt_addstring(username); ssh2_pkt_addstring("ssh-connection"); /* service requested */ ssh2_pkt_addstring("publickey"); /* method */ ssh2_pkt_addbool(TRUE); ssh2_pkt_addstring_start(); ssh2_pkt_addstring_data(alg, alglen); ssh2_pkt_addstring_start(); ssh2_pkt_addstring_data(pkblob, pklen); siglen = pktout.length - 5 + 4 + 20; len = 1; /* message type */ len += 4 + pklen; /* key blob */ len += 4 + siglen; /* data to sign */ len += 4; /* flags */ agentreq = smalloc(4 + len); PUT_32BIT(agentreq, len); q = agentreq + 4; *q++ = SSH2_AGENTC_SIGN_REQUEST; PUT_32BIT(q, pklen); q += 4; memcpy(q, pkblob, pklen); q += pklen; PUT_32BIT(q, siglen); q += 4; /* Now the data to be signed... */ PUT_32BIT(q, 20); q += 4; memcpy(q, ssh2_session_id, 20); q += 20; memcpy(q, pktout.data+5, pktout.length-5); q += pktout.length-5; /* And finally the (zero) flags word. */ PUT_32BIT(q, 0); agent_query(agentreq, len+4, &ret, &retlen); sfree(agentreq); if (ret) { if (ret[4] == SSH2_AGENT_SIGN_RESPONSE) { logevent("Sending Pageant's response"); ssh2_pkt_addstring_start(); ssh2_pkt_addstring_data(ret+9, GET_32BIT(ret+5)); ssh2_pkt_send(); authed = TRUE; break; } else { logevent("Pageant failed to answer challenge"); sfree(ret); } } } if (authed) continue; } } if (!method && can_pubkey && *cfg.keyfile && !tried_pubkey_config) { unsigned char *pub_blob; char *algorithm, *comment; int pub_blob_len; tried_pubkey_config = TRUE; /* * 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 = ssh2_userkey_loadpub(cfg.keyfile, &algorithm, &pub_blob_len); if (pub_blob) { ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST); ssh2_pkt_addstring(username); ssh2_pkt_addstring("ssh-connection"); /* service requested */ ssh2_pkt_addstring("publickey");/* method */ ssh2_pkt_addbool(FALSE); /* no signature included */ ssh2_pkt_addstring(algorithm); ssh2_pkt_addstring_start(); ssh2_pkt_addstring_data(pub_blob, pub_blob_len); ssh2_pkt_send(); logevent("Offered public key"); /* FIXME */ crWaitUntilV(ispkt); if (pktin.type != SSH2_MSG_USERAUTH_PK_OK) { gotit = TRUE; 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(cfg.keyfile, &comment)) { sprintf(pwprompt, "Passphrase for key \"%.100s\": ", comment); need_pw = TRUE; } else { need_pw = FALSE; } c_write_str("Authenticating with public key \""); c_write_str(comment); c_write_str("\"\r\n"); method = AUTH_PUBLICKEY_FILE; } } if (!method && can_passwd) { method = AUTH_PASSWORD; sprintf(pwprompt, "%.90s@%.90s's password: ", username, savedhost); need_pw = TRUE; } if (need_pw) { if (ssh_get_line) { if (!ssh_get_line(pwprompt, password, sizeof(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. */ logevent("No more passwords to try"); ssh_state = SSH_STATE_CLOSED; crReturnV; } } else { static int pos = 0; static char c; c_write_str(pwprompt); ssh_send_ok = 1; pos = 0; while (pos >= 0) { crWaitUntilV(!ispkt); while (inlen--) switch (c = *in++) { case 10: case 13: password[pos] = 0; pos = -1; break; case 8: case 127: if (pos > 0) pos--; break; case 21: case 27: pos = 0; break; case 3: case 4: random_save_seed(); exit(0); break; default: if (((c >= ' ' && c <= '~') || ((unsigned char)c >= 160)) && pos < 40) password[pos++] = c; break; } } c_write_str("\r\n"); } } if (method == AUTH_PUBLICKEY_FILE) { /* * We have our passphrase. Now try the actual authentication. */ struct ssh2_userkey *key; key = ssh2_load_userkey(cfg.keyfile, password); if (key == SSH2_WRONG_PASSPHRASE || key == NULL) { if (key == SSH2_WRONG_PASSPHRASE) { c_write_str("Wrong passphrase\r\n"); tried_pubkey_config = FALSE; } else { c_write_str("Unable to load private key\r\n"); tried_pubkey_config = TRUE; } /* Send a spurious AUTH_NONE to return to the top. */ ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST); ssh2_pkt_addstring(username); ssh2_pkt_addstring("ssh-connection"); /* service requested */ ssh2_pkt_addstring("none"); /* method */ ssh2_pkt_send(); type = AUTH_TYPE_NONE; } else { unsigned char *blob, *sigdata; int blob_len, sigdata_len; /* * 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. */ ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST); ssh2_pkt_addstring(username); ssh2_pkt_addstring("ssh-connection"); /* service requested */ ssh2_pkt_addstring("publickey"); /* method */ ssh2_pkt_addbool(TRUE); ssh2_pkt_addstring(key->alg->name); blob = key->alg->public_blob(key->data, &blob_len); ssh2_pkt_addstring_start(); ssh2_pkt_addstring_data(blob, blob_len); sfree(blob); /* * The data to be signed is: * * string session-id * * followed by everything so far placed in the * outgoing packet. */ sigdata_len = pktout.length - 5 + 4 + 20; sigdata = smalloc(sigdata_len); PUT_32BIT(sigdata, 20); memcpy(sigdata+4, ssh2_session_id, 20); memcpy(sigdata+24, pktout.data+5, pktout.length-5); blob = key->alg->sign(key->data, sigdata, sigdata_len, &blob_len); ssh2_pkt_addstring_start(); ssh2_pkt_addstring_data(blob, blob_len); sfree(blob); sfree(sigdata); ssh2_pkt_send(); type = AUTH_TYPE_PUBLICKEY; } } else if (method == AUTH_PASSWORD) { /* * We send the password packet lumped tightly together with * an SSH_MSG_IGNORE packet. The IGNORE packet contains a * string long enough to make the total length of the two * packets constant. This should ensure that a passive * listener doing traffic analyis can't work out the length * of the password. * * For this to work, we need an assumption about the * maximum length of the password packet. I think 256 is * pretty conservative. Anyone using a password longer than * that probably doesn't have much to worry about from * people who find out how long their password is! */ ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST); ssh2_pkt_addstring(username); ssh2_pkt_addstring("ssh-connection"); /* service requested */ ssh2_pkt_addstring("password"); ssh2_pkt_addbool(FALSE); ssh2_pkt_addstring(password); ssh2_pkt_defer(); /* * We'll include a string that's an exact multiple of the * cipher block size. If the cipher is NULL for some * reason, we don't do this trick at all because we gain * nothing by it. */ if (cscipher) { int stringlen, i; stringlen = (256 - deferred_len); stringlen += cscipher->blksize - 1; stringlen -= (stringlen % cscipher->blksize); if (cscomp) { /* * Temporarily disable actual compression, * so we can guarantee to get this string * exactly the length we want it. The * compression-disabling routine should * return an integer indicating how many * bytes we should adjust our string length * by. */ stringlen -= cscomp->disable_compression(); } ssh2_pkt_init(SSH2_MSG_IGNORE); ssh2_pkt_addstring_start(); for (i = 0; i < stringlen; i++) { char c = (char)random_byte(); ssh2_pkt_addstring_data(&c, 1); } ssh2_pkt_defer(); } ssh_pkt_defersend(); logevent("Sent password"); type = AUTH_TYPE_PASSWORD; } else { c_write_str("No supported authentication methods left to try!\r\n"); logevent("No supported authentications offered. Disconnecting"); ssh2_pkt_init(SSH2_MSG_DISCONNECT); ssh2_pkt_adduint32(SSH2_DISCONNECT_BY_APPLICATION); ssh2_pkt_addstring("No supported authentication methods available"); ssh2_pkt_addstring("en"); /* language tag */ ssh2_pkt_send(); ssh_state = SSH_STATE_CLOSED; crReturnV; } } } while (!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. */ /* * So now create a channel with a session in it. */ mainchan = smalloc(sizeof(struct ssh_channel)); mainchan->localid = 100; /* as good as any */ ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN); ssh2_pkt_addstring("session"); ssh2_pkt_adduint32(mainchan->localid); ssh2_pkt_adduint32(0x8000UL); /* our window size */ ssh2_pkt_adduint32(0x4000UL); /* our max pkt size */ ssh2_pkt_send(); crWaitUntilV(ispkt); if (pktin.type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) { bombout(("Server refused to open a session")); crReturnV; /* FIXME: error data comes back in FAILURE packet */ } if (ssh2_pkt_getuint32() != mainchan->localid) { bombout(("Server's channel confirmation cited wrong channel")); crReturnV; } mainchan->remoteid = ssh2_pkt_getuint32(); mainchan->type = CHAN_MAINSESSION; mainchan->closes = 0; mainchan->v2.remwindow = ssh2_pkt_getuint32(); mainchan->v2.remmaxpkt = ssh2_pkt_getuint32(); mainchan->v2.outbuffer = NULL; mainchan->v2.outbuflen = mainchan->v2.outbufsize = 0; ssh_channels = newtree234(ssh_channelcmp); add234(ssh_channels, mainchan); logevent("Opened channel for session"); /* * Potentially enable X11 forwarding. */ if (cfg.x11_forward) { char proto[20], data[64]; logevent("Requesting X11 forwarding"); x11_invent_auth(proto, sizeof(proto), data, sizeof(data)); ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST); ssh2_pkt_adduint32(mainchan->remoteid); ssh2_pkt_addstring("x11-req"); ssh2_pkt_addbool(1); /* want reply */ ssh2_pkt_addbool(0); /* many connections */ ssh2_pkt_addstring(proto); ssh2_pkt_addstring(data); ssh2_pkt_adduint32(0); /* screen number */ ssh2_pkt_send(); do { crWaitUntilV(ispkt); if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) { unsigned i = ssh2_pkt_getuint32(); struct ssh_channel *c; c = find234(ssh_channels, &i, ssh_channelfind); if (!c) continue; /* nonexistent channel */ c->v2.remwindow += ssh2_pkt_getuint32(); } } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST); if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) { if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) { bombout(("Server got confused by X11 forwarding request")); crReturnV; } logevent("X11 forwarding refused"); } else { logevent("X11 forwarding enabled"); ssh_X11_fwd_enabled = TRUE; } } /* * Potentially enable agent forwarding. */ if (cfg.agentfwd && agent_exists()) { logevent("Requesting OpenSSH-style agent forwarding"); ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST); ssh2_pkt_adduint32(mainchan->remoteid); ssh2_pkt_addstring("auth-agent-req@openssh.com"); ssh2_pkt_addbool(1); /* want reply */ ssh2_pkt_send(); do { crWaitUntilV(ispkt); if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) { unsigned i = ssh2_pkt_getuint32(); struct ssh_channel *c; c = find234(ssh_channels, &i, ssh_channelfind); if (!c) continue; /* nonexistent channel */ c->v2.remwindow += ssh2_pkt_getuint32(); } } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST); if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) { if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) { bombout(("Server got confused by agent forwarding request")); crReturnV; } logevent("Agent forwarding refused"); } else { logevent("Agent forwarding enabled"); ssh_agentfwd_enabled = TRUE; } } /* * Now allocate a pty for the session. */ if (!cfg.nopty) { ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST); ssh2_pkt_adduint32(mainchan->remoteid); /* recipient channel */ ssh2_pkt_addstring("pty-req"); ssh2_pkt_addbool(1); /* want reply */ ssh2_pkt_addstring(cfg.termtype); ssh2_pkt_adduint32(cols); ssh2_pkt_adduint32(rows); ssh2_pkt_adduint32(0); /* pixel width */ ssh2_pkt_adduint32(0); /* pixel height */ ssh2_pkt_addstring_start(); ssh2_pkt_addstring_data("\0", 1);/* TTY_OP_END, no special options */ ssh2_pkt_send(); ssh_state = SSH_STATE_INTERMED; do { crWaitUntilV(ispkt); if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) { unsigned i = ssh2_pkt_getuint32(); struct ssh_channel *c; c = find234(ssh_channels, &i, ssh_channelfind); if (!c) continue; /* nonexistent channel */ c->v2.remwindow += ssh2_pkt_getuint32(); } } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST); if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) { if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) { bombout(("Server got confused by pty request")); crReturnV; } c_write_str("Server refused to allocate pty\r\n"); ssh_editing = ssh_echoing = 1; } else { logevent("Allocated pty"); } } else { ssh_editing = ssh_echoing = 1; } /* * Start a shell or a remote command. */ ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST); ssh2_pkt_adduint32(mainchan->remoteid); /* recipient channel */ if (cfg.ssh_subsys) { ssh2_pkt_addstring("subsystem"); ssh2_pkt_addbool(1); /* want reply */ ssh2_pkt_addstring(cfg.remote_cmd_ptr); } else if (*cfg.remote_cmd_ptr) { ssh2_pkt_addstring("exec"); ssh2_pkt_addbool(1); /* want reply */ ssh2_pkt_addstring(cfg.remote_cmd_ptr); } else { ssh2_pkt_addstring("shell"); ssh2_pkt_addbool(1); /* want reply */ } ssh2_pkt_send(); do { crWaitUntilV(ispkt); if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) { unsigned i = ssh2_pkt_getuint32(); struct ssh_channel *c; c = find234(ssh_channels, &i, ssh_channelfind); if (!c) continue; /* nonexistent channel */ c->v2.remwindow += ssh2_pkt_getuint32(); } } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST); if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) { if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) { bombout(("Server got confused by shell/command request")); crReturnV; } bombout(("Server refused to start a shell/command")); crReturnV; } else { logevent("Started a shell/command"); } ssh_state = SSH_STATE_SESSION; if (size_needed) ssh_size(); if (eof_needed) ssh_special(TS_EOF); /* * Transfer data! */ ldisc_send(NULL, 0); /* cause ldisc to notice changes */ ssh_send_ok = 1; while (1) { static int try_send; crReturnV; try_send = FALSE; if (ispkt) { if (pktin.type == SSH2_MSG_CHANNEL_DATA || pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA) { char *data; int length; unsigned i = ssh2_pkt_getuint32(); struct ssh_channel *c; c = find234(ssh_channels, &i, ssh_channelfind); if (!c) continue; /* nonexistent channel */ if (pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA && ssh2_pkt_getuint32() != SSH2_EXTENDED_DATA_STDERR) continue; /* extended but not stderr */ ssh2_pkt_getstring(&data, &length); if (data) { switch (c->type) { case CHAN_MAINSESSION: from_backend(pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA, data, length); break; case CHAN_X11: x11_send(c->u.x11.s, data, length); break; case CHAN_AGENT: while (length > 0) { if (c->u.a.lensofar < 4) { 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 = smalloc(c->u.a.totallen); memcpy(c->u.a.message, c->u.a.msglen, 4); } if (c->u.a.lensofar >= 4 && length > 0) { 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, *sentreply; int replylen; agent_query(c->u.a.message, c->u.a.totallen, &reply, &replylen); if (reply) sentreply = reply; else { /* Fake SSH_AGENT_FAILURE. */ sentreply = "\0\0\0\1\5"; replylen = 5; } ssh2_add_channel_data(c, sentreply, replylen); try_send = TRUE; if (reply) sfree(reply); sfree(c->u.a.message); c->u.a.lensofar = 0; } } break; } /* * Enlarge the window again at the remote * side, just in case it ever runs down and * they fail to send us any more data. */ ssh2_pkt_init(SSH2_MSG_CHANNEL_WINDOW_ADJUST); ssh2_pkt_adduint32(c->remoteid); ssh2_pkt_adduint32(length); ssh2_pkt_send(); } } else if (pktin.type == SSH2_MSG_DISCONNECT) { ssh_state = SSH_STATE_CLOSED; logevent("Received disconnect message"); crReturnV; } else if (pktin.type == SSH2_MSG_CHANNEL_REQUEST) { continue; /* exit status et al; ignore (FIXME?) */ } else if (pktin.type == SSH2_MSG_CHANNEL_EOF) { unsigned i = ssh2_pkt_getuint32(); struct ssh_channel *c; c = find234(ssh_channels, &i, ssh_channelfind); if (!c) continue; /* 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 (pktin.type == SSH2_MSG_CHANNEL_CLOSE) { unsigned i = ssh2_pkt_getuint32(); struct ssh_channel *c; enum234 e; c = find234(ssh_channels, &i, ssh_channelfind); if (!c) continue; /* nonexistent channel */ if (c->closes == 0) { ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE); ssh2_pkt_adduint32(c->remoteid); ssh2_pkt_send(); } /* Do pre-close processing on the channel. */ switch (c->type) { case CHAN_MAINSESSION: break; /* nothing to see here, move along */ case CHAN_X11: break; case CHAN_AGENT: break; } del234(ssh_channels, c); sfree(c->v2.outbuffer); sfree(c); /* * See if that was the last channel left open. */ c = first234(ssh_channels, &e); if (!c) { logevent("All channels closed. Disconnecting"); ssh2_pkt_init(SSH2_MSG_DISCONNECT); ssh2_pkt_adduint32(SSH2_DISCONNECT_BY_APPLICATION); ssh2_pkt_addstring("All open channels closed"); ssh2_pkt_addstring("en"); /* language tag */ ssh2_pkt_send(); ssh_state = SSH_STATE_CLOSED; crReturnV; } continue; /* remote sends close; ignore (FIXME) */ } else if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) { unsigned i = ssh2_pkt_getuint32(); struct ssh_channel *c; c = find234(ssh_channels, &i, ssh_channelfind); if (!c) continue; /* nonexistent channel */ c->v2.remwindow += ssh2_pkt_getuint32(); try_send = TRUE; } else if (pktin.type == SSH2_MSG_CHANNEL_OPEN) { char *type; int typelen; char *error = NULL; struct ssh_channel *c; ssh2_pkt_getstring(&type, &typelen); c = smalloc(sizeof(struct ssh_channel)); if (typelen == 3 && !memcmp(type, "x11", 3)) { if (!ssh_X11_fwd_enabled) error = "X11 forwarding is not enabled"; else if ( x11_init(&c->u.x11.s, cfg.x11_display, c) != NULL ) { error = "Unable to open an X11 connection"; } else { c->type = CHAN_X11; } } 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 = ssh2_pkt_getuint32(); if (error) { ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_FAILURE); ssh2_pkt_adduint32(c->remoteid); ssh2_pkt_adduint32(SSH2_OPEN_CONNECT_FAILED); ssh2_pkt_addstring(error); ssh2_pkt_addstring("en"); /* language tag */ ssh2_pkt_send(); sfree(c); } else { struct ssh_channel *d; unsigned i; enum234 e; for (i=1, d = first234(ssh_channels, &e); d; d = next234(&e)) { if (d->localid > i) break; /* found a free number */ i = d->localid + 1; } c->localid = i; c->closes = 0; c->v2.remwindow = ssh2_pkt_getuint32(); c->v2.remmaxpkt = ssh2_pkt_getuint32(); c->v2.outbuffer = NULL; c->v2.outbuflen = c->v2.outbufsize = 0; add234(ssh_channels, c); ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); ssh2_pkt_adduint32(c->remoteid); ssh2_pkt_adduint32(c->localid); ssh2_pkt_adduint32(0x8000UL); /* our window size */ ssh2_pkt_adduint32(0x4000UL); /* our max pkt size */ ssh2_pkt_send(); } } else { bombout(("Strange packet received: type %d", pktin.type)); crReturnV; } } else { /* * We have spare data. Add it to the channel buffer. */ ssh2_add_channel_data(mainchan, in, inlen); try_send = TRUE; } if (try_send) { enum234 e; struct ssh_channel *c; /* * Try to send data on all channels if we can. */ for (c = first234(ssh_channels, &e); c; c = next234(&e)) ssh2_try_send(c); } } crFinishV; } /* * Handle the top-level SSH2 protocol. */ static void ssh2_protocol(unsigned char *in, int inlen, int ispkt) { if (do_ssh2_transport(in, inlen, ispkt) == 0) return; do_ssh2_authconn(in, inlen, ispkt); } /* * Called to set up the connection. * * Returns an error message, or NULL on success. */ static char *ssh_init (char *host, int port, char **realhost) { char *p; #ifdef MSCRYPTOAPI if(crypto_startup() == 0) return "Microsoft high encryption pack not installed!"; #endif ssh_send_ok = 0; ssh_editing = 0; ssh_echoing = 0; p = connect_to_host(host, port, realhost); if (p != NULL) return p; return NULL; } /* * Called to send data down the Telnet connection. */ static void ssh_send (char *buf, int len) { if (s == NULL || ssh_protocol == NULL) return; ssh_protocol(buf, len, 0); } /* * Called to set the size of the window from SSH's POV. */ static void ssh_size(void) { switch (ssh_state) { case SSH_STATE_BEFORE_SIZE: case SSH_STATE_PREPACKET: case SSH_STATE_CLOSED: break; /* do nothing */ case SSH_STATE_INTERMED: size_needed = TRUE; /* buffer for later */ break; case SSH_STATE_SESSION: if (!cfg.nopty) { if (ssh_version == 1) { send_packet(SSH1_CMSG_WINDOW_SIZE, PKT_INT, rows, PKT_INT, cols, PKT_INT, 0, PKT_INT, 0, PKT_END); } else { ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST); ssh2_pkt_adduint32(mainchan->remoteid); ssh2_pkt_addstring("window-change"); ssh2_pkt_addbool(0); ssh2_pkt_adduint32(cols); ssh2_pkt_adduint32(rows); ssh2_pkt_adduint32(0); ssh2_pkt_adduint32(0); ssh2_pkt_send(); } } break; } } /* * 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 (Telnet_Special code) { 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) eof_needed = TRUE; return; } if (ssh_version == 1) { send_packet(SSH1_CMSG_EOF, PKT_END); } else { ssh2_pkt_init(SSH2_MSG_CHANNEL_EOF); ssh2_pkt_adduint32(mainchan->remoteid); ssh2_pkt_send(); } logevent("Sent EOF message"); } else if (code == TS_PING) { if (ssh_state == SSH_STATE_CLOSED || ssh_state == SSH_STATE_PREPACKET) return; if (ssh_version == 1) { send_packet(SSH1_MSG_IGNORE, PKT_STR, "", PKT_END); } else { ssh2_pkt_init(SSH2_MSG_IGNORE); ssh2_pkt_addstring_start(); ssh2_pkt_send(); } } else { /* do nothing */ } } static Socket ssh_socket(void) { return s; } static int ssh_sendok(void) { return ssh_send_ok; } static int ssh_ldisc(int option) { if (option == LD_ECHO) return ssh_echoing; if (option == LD_EDIT) return ssh_editing; return FALSE; } Backend ssh_backend = { ssh_init, ssh_send, ssh_size, ssh_special, ssh_socket, ssh_sendok, ssh_ldisc, 22 };