+ ssh2_pkt_addbyte(pktout, ssh_ttymodes[i].opcode);
+ ssh2_pkt_addbyte(pktout, arg);
+}
+
+
+static void do_ssh1_connection(Ssh ssh, unsigned char *in, int inlen,
+ struct Packet *pktin)
+{
+ crBegin(ssh->do_ssh1_connection_crstate);
+
+ ssh->packet_dispatch[SSH1_SMSG_STDOUT_DATA] =
+ ssh->packet_dispatch[SSH1_SMSG_STDERR_DATA] =
+ ssh1_smsg_stdout_stderr_data;
+
+ ssh->packet_dispatch[SSH1_MSG_CHANNEL_OPEN_CONFIRMATION] =
+ ssh1_msg_channel_open_confirmation;
+ ssh->packet_dispatch[SSH1_MSG_CHANNEL_OPEN_FAILURE] =
+ ssh1_msg_channel_open_failure;
+ ssh->packet_dispatch[SSH1_MSG_CHANNEL_CLOSE] =
+ ssh->packet_dispatch[SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION] =
+ ssh1_msg_channel_close;
+ ssh->packet_dispatch[SSH1_MSG_CHANNEL_DATA] = ssh1_msg_channel_data;
+ ssh->packet_dispatch[SSH1_SMSG_EXIT_STATUS] = ssh1_smsg_exit_status;
+
+ if (ssh->cfg.agentfwd && agent_exists()) {
+ logevent("Requesting agent forwarding");
+ send_packet(ssh, SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END);
+ do {
+ crReturnV;
+ } while (!pktin);
+ if (pktin->type != SSH1_SMSG_SUCCESS
+ && pktin->type != SSH1_SMSG_FAILURE) {
+ bombout(("Protocol confusion"));
+ crStopV;
+ } else if (pktin->type == SSH1_SMSG_FAILURE) {
+ logevent("Agent forwarding refused");
+ } else {
+ logevent("Agent forwarding enabled");
+ ssh->agentfwd_enabled = TRUE;
+ ssh->packet_dispatch[SSH1_SMSG_AGENT_OPEN] = ssh1_smsg_agent_open;
+ }
+ }
+
+ if (ssh->cfg.x11_forward) {
+ char proto[20], data[64];
+ logevent("Requesting X11 forwarding");
+ ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
+ data, sizeof(data), ssh->cfg.x11_auth);
+ x11_get_real_auth(ssh->x11auth, ssh->cfg.x11_display);
+ if (ssh->v1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) {
+ send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
+ PKT_STR, proto, PKT_STR, data,
+ PKT_INT, x11_get_screen_number(ssh->cfg.x11_display),
+ PKT_END);
+ } else {
+ send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
+ PKT_STR, proto, PKT_STR, data, PKT_END);
+ }
+ do {
+ crReturnV;
+ } while (!pktin);
+ if (pktin->type != SSH1_SMSG_SUCCESS
+ && pktin->type != SSH1_SMSG_FAILURE) {
+ bombout(("Protocol confusion"));
+ crStopV;
+ } else if (pktin->type == SSH1_SMSG_FAILURE) {
+ logevent("X11 forwarding refused");
+ } else {
+ logevent("X11 forwarding enabled");
+ ssh->X11_fwd_enabled = TRUE;
+ ssh->packet_dispatch[SSH1_SMSG_X11_OPEN] = ssh1_smsg_x11_open;
+ }
+ }
+
+ ssh_setup_portfwd(ssh, &ssh->cfg);
+ ssh->packet_dispatch[SSH1_MSG_PORT_OPEN] = ssh1_msg_port_open;
+
+ if (!ssh->cfg.nopty) {
+ struct Packet *pkt;
+ /* Unpick the terminal-speed string. */
+ /* XXX perhaps we should allow no speeds to be sent. */
+ ssh->ospeed = 38400; ssh->ispeed = 38400; /* last-resort defaults */
+ sscanf(ssh->cfg.termspeed, "%d,%d", &ssh->ospeed, &ssh->ispeed);
+ /* Send the pty request. */
+ pkt = ssh1_pkt_init(SSH1_CMSG_REQUEST_PTY);
+ ssh_pkt_addstring(pkt, ssh->cfg.termtype);
+ ssh_pkt_adduint32(pkt, ssh->term_height);
+ ssh_pkt_adduint32(pkt, ssh->term_width);
+ ssh_pkt_adduint32(pkt, 0); /* width in pixels */
+ ssh_pkt_adduint32(pkt, 0); /* height in pixels */
+ parse_ttymodes(ssh, ssh->cfg.ttymodes,
+ ssh1_send_ttymode, (void *)pkt);
+ ssh_pkt_addbyte(pkt, SSH1_TTY_OP_ISPEED);
+ ssh_pkt_adduint32(pkt, ssh->ispeed);
+ ssh_pkt_addbyte(pkt, SSH1_TTY_OP_OSPEED);
+ ssh_pkt_adduint32(pkt, ssh->ospeed);
+ ssh_pkt_addbyte(pkt, SSH_TTY_OP_END);
+ s_wrpkt(ssh, pkt);
+ ssh->state = SSH_STATE_INTERMED;
+ do {
+ crReturnV;
+ } while (!pktin);
+ if (pktin->type != SSH1_SMSG_SUCCESS
+ && pktin->type != SSH1_SMSG_FAILURE) {
+ bombout(("Protocol confusion"));
+ crStopV;
+ } else if (pktin->type == SSH1_SMSG_FAILURE) {
+ c_write_str(ssh, "Server refused to allocate pty\r\n");
+ ssh->editing = ssh->echoing = 1;
+ }
+ logeventf(ssh, "Allocated pty (ospeed %dbps, ispeed %dbps)",
+ ssh->ospeed, ssh->ispeed);
+ } else {
+ ssh->editing = ssh->echoing = 1;
+ }
+
+ if (ssh->cfg.compression) {
+ send_packet(ssh, SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
+ do {
+ crReturnV;
+ } while (!pktin);
+ if (pktin->type != SSH1_SMSG_SUCCESS
+ && pktin->type != SSH1_SMSG_FAILURE) {
+ bombout(("Protocol confusion"));
+ crStopV;
+ } else if (pktin->type == SSH1_SMSG_FAILURE) {
+ c_write_str(ssh, "Server refused to compress\r\n");
+ }
+ logevent("Started compression");
+ ssh->v1_compressing = TRUE;
+ ssh->cs_comp_ctx = zlib_compress_init();
+ logevent("Initialised zlib (RFC1950) compression");
+ ssh->sc_comp_ctx = zlib_decompress_init();
+ logevent("Initialised zlib (RFC1950) decompression");
+ }
+
+ /*
+ * Start the shell or command.
+ *
+ * Special case: if the first-choice command is an SSH-2
+ * subsystem (hence not usable here) and the second choice
+ * exists, we fall straight back to that.
+ */
+ {
+ char *cmd = ssh->cfg.remote_cmd_ptr;
+
+ if (!cmd) cmd = ssh->cfg.remote_cmd;
+
+ if (ssh->cfg.ssh_subsys && ssh->cfg.remote_cmd_ptr2) {
+ cmd = ssh->cfg.remote_cmd_ptr2;
+ ssh->fallback_cmd = TRUE;
+ }
+ if (*cmd)
+ send_packet(ssh, SSH1_CMSG_EXEC_CMD, PKT_STR, cmd, PKT_END);
+ else
+ send_packet(ssh, SSH1_CMSG_EXEC_SHELL, PKT_END);
+ logevent("Started session");
+ }
+
+ ssh->state = SSH_STATE_SESSION;
+ if (ssh->size_needed)
+ ssh_size(ssh, ssh->term_width, ssh->term_height);
+ if (ssh->eof_needed)
+ ssh_special(ssh, TS_EOF);
+
+ if (ssh->ldisc)
+ ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */
+ ssh->send_ok = 1;
+ ssh->channels = newtree234(ssh_channelcmp);
+ while (1) {
+
+ /*
+ * By this point, most incoming packets are already being
+ * handled by the dispatch table, and we need only pay
+ * attention to the unusual ones.
+ */
+
+ crReturnV;
+ if (pktin) {
+ if (pktin->type == SSH1_SMSG_SUCCESS) {
+ /* may be from EXEC_SHELL on some servers */
+ } else if (pktin->type == SSH1_SMSG_FAILURE) {
+ /* may be from EXEC_SHELL on some servers
+ * if no pty is available or in other odd cases. Ignore */
+ } else {
+ bombout(("Strange packet received: type %d", pktin->type));
+ crStopV;
+ }
+ } else {
+ while (inlen > 0) {
+ int len = min(inlen, 512);
+ send_packet(ssh, SSH1_CMSG_STDIN_DATA, PKTT_DATA,
+ PKT_INT, len, PKT_DATA, in, len,
+ PKTT_OTHER, PKT_END);
+ in += len;
+ inlen -= len;
+ }
+ }
+ }
+
+ crFinishV;
+}
+
+/*
+ * Handle the top-level SSH-2 protocol.
+ */
+static void ssh1_msg_debug(Ssh ssh, struct Packet *pktin)
+{
+ char *msg;
+ int msglen;
+
+ ssh_pkt_getstring(pktin, &msg, &msglen);
+ logeventf(ssh, "Remote debug message: %.*s", msglen, msg);
+}
+
+static void ssh1_msg_disconnect(Ssh ssh, struct Packet *pktin)
+{
+ /* log reason code in disconnect message */
+ char *msg;
+ int msglen;
+
+ ssh_pkt_getstring(pktin, &msg, &msglen);
+ bombout(("Server sent disconnect message:\n\"%.*s\"", msglen, msg));
+}
+
+static void ssh_msg_ignore(Ssh ssh, struct Packet *pktin)
+{
+ /* Do nothing, because we're ignoring it! Duhh. */
+}
+
+static void ssh1_protocol_setup(Ssh ssh)
+{
+ int i;
+
+ /*
+ * Most messages are handled by the coroutines.
+ */
+ for (i = 0; i < 256; i++)
+ ssh->packet_dispatch[i] = NULL;
+
+ /*
+ * These special message types we install handlers for.
+ */
+ ssh->packet_dispatch[SSH1_MSG_DISCONNECT] = ssh1_msg_disconnect;
+ ssh->packet_dispatch[SSH1_MSG_IGNORE] = ssh_msg_ignore;
+ ssh->packet_dispatch[SSH1_MSG_DEBUG] = ssh1_msg_debug;
+}
+
+static void ssh1_protocol(Ssh ssh, void *vin, int inlen,
+ struct Packet *pktin)
+{
+ unsigned char *in=(unsigned char*)vin;
+ if (ssh->state == SSH_STATE_CLOSED)
+ return;
+
+ if (pktin && ssh->packet_dispatch[pktin->type]) {
+ ssh->packet_dispatch[pktin->type](ssh, pktin);
+ return;
+ }
+
+ if (!ssh->protocol_initial_phase_done) {
+ if (do_ssh1_login(ssh, in, inlen, pktin))
+ ssh->protocol_initial_phase_done = TRUE;
+ else
+ return;
+ }
+
+ do_ssh1_connection(ssh, in, inlen, pktin);
+}
+
+/*
+ * Utility routine for decoding comma-separated strings in KEXINIT.
+ */
+static int in_commasep_string(char *needle, char *haystack, int haylen)
+{
+ int needlen;
+ if (!needle || !haystack) /* protect against null pointers */
+ return 0;
+ needlen = strlen(needle);
+ while (1) {
+ /*
+ * Is it at the start of the string?
+ */
+ if (haylen >= needlen && /* haystack is long enough */
+ !memcmp(needle, haystack, needlen) && /* initial match */
+ (haylen == needlen || haystack[needlen] == ',')
+ /* either , or EOS follows */
+ )
+ return 1;
+ /*
+ * If not, search for the next comma and resume after that.
+ * If no comma found, terminate.
+ */
+ while (haylen > 0 && *haystack != ',')
+ haylen--, haystack++;
+ if (haylen == 0)
+ return 0;
+ haylen--, haystack++; /* skip over comma itself */
+ }
+}
+
+/*
+ * Similar routine for checking whether we have the first string in a list.
+ */
+static int first_in_commasep_string(char *needle, char *haystack, int haylen)
+{
+ int needlen;
+ if (!needle || !haystack) /* protect against null pointers */
+ return 0;
+ needlen = strlen(needle);
+ /*
+ * Is it at the start of the string?
+ */
+ if (haylen >= needlen && /* haystack is long enough */
+ !memcmp(needle, haystack, needlen) && /* initial match */
+ (haylen == needlen || haystack[needlen] == ',')
+ /* either , or EOS follows */
+ )
+ return 1;
+ return 0;
+}
+
+
+/*
+ * SSH-2 key creation method.
+ */
+static void ssh2_mkkey(Ssh ssh, Bignum K, unsigned char *H,
+ unsigned char *sessid, char chr,
+ unsigned char *keyspace)
+{
+ SHA_State s;
+ /* First 20 bytes. */
+ SHA_Init(&s);
+ if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
+ sha_mpint(&s, K);
+ SHA_Bytes(&s, H, 20);
+ SHA_Bytes(&s, &chr, 1);
+ SHA_Bytes(&s, sessid, 20);
+ SHA_Final(&s, keyspace);
+ /* Next 20 bytes. */
+ SHA_Init(&s);
+ if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
+ sha_mpint(&s, K);
+ SHA_Bytes(&s, H, 20);
+ SHA_Bytes(&s, keyspace, 20);
+ SHA_Final(&s, keyspace + 20);
+}
+
+/*
+ * Handle the SSH-2 transport layer.
+ */
+static int do_ssh2_transport(Ssh ssh, void *vin, int inlen,
+ struct Packet *pktin)
+{
+ unsigned char *in = (unsigned char *)vin;
+ struct do_ssh2_transport_state {
+ int nbits, pbits, warn_kex, warn_cscipher, warn_sccipher;
+ Bignum p, g, e, f, K;
+ int kex_init_value, kex_reply_value;
+ const struct ssh_mac **maclist;
+ int nmacs;
+ const struct ssh2_cipher *cscipher_tobe;
+ const struct ssh2_cipher *sccipher_tobe;
+ const struct ssh_mac *csmac_tobe;
+ const struct ssh_mac *scmac_tobe;
+ const struct ssh_compress *cscomp_tobe;
+ const struct ssh_compress *sccomp_tobe;
+ char *hostkeydata, *sigdata, *keystr, *fingerprint;
+ int hostkeylen, siglen;
+ void *hkey; /* actual host key */
+ unsigned char exchange_hash[20];
+ int n_preferred_kex;
+ const struct ssh_kex *preferred_kex[KEX_MAX];
+ int n_preferred_ciphers;
+ const struct ssh2_ciphers *preferred_ciphers[CIPHER_MAX];
+ const struct ssh_compress *preferred_comp;
+ int got_session_id, activated_authconn;
+ struct Packet *pktout;
+ int dlgret;
+ int guessok;
+ int ignorepkt;
+ };
+ crState(do_ssh2_transport_state);
+
+ crBegin(ssh->do_ssh2_transport_crstate);
+
+ s->cscipher_tobe = s->sccipher_tobe = NULL;
+ s->csmac_tobe = s->scmac_tobe = NULL;
+ s->cscomp_tobe = s->sccomp_tobe = NULL;
+
+ s->got_session_id = s->activated_authconn = FALSE;
+
+ /*
+ * Be prepared to work around the buggy MAC problem.
+ */
+ if (ssh->remote_bugs & BUG_SSH2_HMAC)
+ s->maclist = buggymacs, s->nmacs = lenof(buggymacs);
+ else
+ s->maclist = macs, s->nmacs = lenof(macs);
+
+ begin_key_exchange:
+ ssh->pkt_ctx &= ~SSH2_PKTCTX_KEX_MASK;
+ {
+ int i, j, commalist_started;
+
+ /*
+ * Set up the preferred key exchange. (NULL => warn below here)
+ */
+ s->n_preferred_kex = 0;
+ for (i = 0; i < KEX_MAX; i++) {
+ switch (ssh->cfg.ssh_kexlist[i]) {
+ case KEX_DHGEX:
+ s->preferred_kex[s->n_preferred_kex++] =
+ &ssh_diffiehellman_gex;
+ break;
+ case KEX_DHGROUP14:
+ s->preferred_kex[s->n_preferred_kex++] =
+ &ssh_diffiehellman_group14;
+ break;
+ case KEX_DHGROUP1:
+ s->preferred_kex[s->n_preferred_kex++] =
+ &ssh_diffiehellman_group1;
+ break;
+ case CIPHER_WARN:
+ /* Flag for later. Don't bother if it's the last in
+ * the list. */
+ if (i < KEX_MAX - 1) {
+ s->preferred_kex[s->n_preferred_kex++] = NULL;
+ }
+ break;
+ }
+ }
+
+ /*
+ * Set up the preferred ciphers. (NULL => warn below here)
+ */
+ s->n_preferred_ciphers = 0;
+ for (i = 0; i < CIPHER_MAX; i++) {
+ switch (ssh->cfg.ssh_cipherlist[i]) {
+ case CIPHER_BLOWFISH:
+ s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_blowfish;
+ break;
+ case CIPHER_DES:
+ if (ssh->cfg.ssh2_des_cbc) {
+ s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_des;
+ }
+ break;
+ case CIPHER_3DES:
+ s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_3des;
+ break;
+ case CIPHER_AES:
+ s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_aes;
+ break;
+ case CIPHER_ARCFOUR:
+ s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_arcfour;
+ break;
+ case CIPHER_WARN:
+ /* Flag for later. Don't bother if it's the last in
+ * the list. */
+ if (i < CIPHER_MAX - 1) {
+ s->preferred_ciphers[s->n_preferred_ciphers++] = NULL;
+ }
+ break;
+ }
+ }
+
+ /*
+ * Set up preferred compression.
+ */
+ if (ssh->cfg.compression)
+ s->preferred_comp = &ssh_zlib;
+ else
+ s->preferred_comp = &ssh_comp_none;
+
+ /*
+ * Enable queueing of outgoing auth- or connection-layer
+ * packets while we are in the middle of a key exchange.
+ */
+ ssh->queueing = TRUE;
+
+ /*
+ * Flag that KEX is in progress.
+ */
+ ssh->kex_in_progress = TRUE;
+
+ /*
+ * Construct and send our key exchange packet.
+ */
+ s->pktout = ssh2_pkt_init(SSH2_MSG_KEXINIT);
+ for (i = 0; i < 16; i++)
+ ssh2_pkt_addbyte(s->pktout, (unsigned char) random_byte());
+ /* List key exchange algorithms. */
+ ssh2_pkt_addstring_start(s->pktout);
+ commalist_started = 0;
+ for (i = 0; i < s->n_preferred_kex; i++) {
+ const struct ssh_kex *k = s->preferred_kex[i];
+ if (!k) continue; /* warning flag */
+ if (commalist_started)
+ ssh2_pkt_addstring_str(s->pktout, ",");
+ ssh2_pkt_addstring_str(s->pktout, s->preferred_kex[i]->name);
+ commalist_started = 1;
+ }
+ /* List server host key algorithms. */
+ ssh2_pkt_addstring_start(s->pktout);
+ for (i = 0; i < lenof(hostkey_algs); i++) {
+ ssh2_pkt_addstring_str(s->pktout, hostkey_algs[i]->name);
+ if (i < lenof(hostkey_algs) - 1)
+ ssh2_pkt_addstring_str(s->pktout, ",");
+ }
+ /* List client->server encryption algorithms. */
+ ssh2_pkt_addstring_start(s->pktout);
+ commalist_started = 0;
+ for (i = 0; i < s->n_preferred_ciphers; i++) {
+ const struct ssh2_ciphers *c = s->preferred_ciphers[i];
+ if (!c) continue; /* warning flag */
+ for (j = 0; j < c->nciphers; j++) {
+ if (commalist_started)
+ ssh2_pkt_addstring_str(s->pktout, ",");
+ ssh2_pkt_addstring_str(s->pktout, c->list[j]->name);
+ commalist_started = 1;
+ }
+ }
+ /* List server->client encryption algorithms. */
+ ssh2_pkt_addstring_start(s->pktout);
+ commalist_started = 0;
+ for (i = 0; i < s->n_preferred_ciphers; i++) {
+ const struct ssh2_ciphers *c = s->preferred_ciphers[i];
+ if (!c) continue; /* warning flag */
+ for (j = 0; j < c->nciphers; j++) {
+ if (commalist_started)
+ ssh2_pkt_addstring_str(s->pktout, ",");
+ ssh2_pkt_addstring_str(s->pktout, c->list[j]->name);
+ commalist_started = 1;
+ }
+ }
+ /* List client->server MAC algorithms. */
+ ssh2_pkt_addstring_start(s->pktout);
+ for (i = 0; i < s->nmacs; i++) {
+ ssh2_pkt_addstring_str(s->pktout, s->maclist[i]->name);
+ if (i < s->nmacs - 1)
+ ssh2_pkt_addstring_str(s->pktout, ",");
+ }
+ /* List server->client MAC algorithms. */
+ ssh2_pkt_addstring_start(s->pktout);
+ for (i = 0; i < s->nmacs; i++) {
+ ssh2_pkt_addstring_str(s->pktout, s->maclist[i]->name);
+ if (i < s->nmacs - 1)
+ ssh2_pkt_addstring_str(s->pktout, ",");
+ }
+ /* List client->server compression algorithms. */
+ ssh2_pkt_addstring_start(s->pktout);
+ assert(lenof(compressions) > 1);
+ ssh2_pkt_addstring_str(s->pktout, s->preferred_comp->name);
+ for (i = 0; i < lenof(compressions); i++) {
+ const struct ssh_compress *c = compressions[i];
+ if (c != s->preferred_comp) {
+ ssh2_pkt_addstring_str(s->pktout, ",");
+ ssh2_pkt_addstring_str(s->pktout, c->name);
+ }
+ }
+ /* List server->client compression algorithms. */
+ ssh2_pkt_addstring_start(s->pktout);
+ assert(lenof(compressions) > 1);
+ ssh2_pkt_addstring_str(s->pktout, s->preferred_comp->name);
+ for (i = 0; i < lenof(compressions); i++) {
+ const struct ssh_compress *c = compressions[i];
+ if (c != s->preferred_comp) {
+ ssh2_pkt_addstring_str(s->pktout, ",");
+ ssh2_pkt_addstring_str(s->pktout, c->name);
+ }
+ }
+ /* List client->server languages. Empty list. */
+ ssh2_pkt_addstring_start(s->pktout);
+ /* List server->client languages. Empty list. */
+ ssh2_pkt_addstring_start(s->pktout);
+ /* First KEX packet does _not_ follow, because we're not that brave. */
+ ssh2_pkt_addbool(s->pktout, FALSE);
+ /* Reserved. */
+ ssh2_pkt_adduint32(s->pktout, 0);
+ }
+
+ ssh->exhash = ssh->exhashbase;
+ sha_string(&ssh->exhash, s->pktout->data + 5, s->pktout->length - 5);
+
+ ssh2_pkt_send_noqueue(ssh, s->pktout);
+
+ if (!pktin)
+ crWaitUntil(pktin);
+ if (pktin->length > 5)
+ sha_string(&ssh->exhash, pktin->data + 5, pktin->length - 5);
+
+ /*
+ * Now examine the other side's KEXINIT to see what we're up
+ * to.
+ */
+ {
+ char *str, *preferred;
+ int i, j, len;
+
+ if (pktin->type != SSH2_MSG_KEXINIT) {
+ bombout(("expected key exchange packet from server"));
+ crStop(0);
+ }
+ ssh->kex = NULL;
+ ssh->hostkey = NULL;
+ s->cscipher_tobe = NULL;
+ s->sccipher_tobe = NULL;
+ s->csmac_tobe = NULL;
+ s->scmac_tobe = NULL;
+ s->cscomp_tobe = NULL;
+ s->sccomp_tobe = NULL;
+ s->warn_kex = s->warn_cscipher = s->warn_sccipher = FALSE;
+
+ pktin->savedpos += 16; /* skip garbage cookie */
+ ssh_pkt_getstring(pktin, &str, &len); /* key exchange algorithms */
+
+ preferred = NULL;
+ for (i = 0; i < s->n_preferred_kex; i++) {
+ const struct ssh_kex *k = s->preferred_kex[i];
+ if (!k) {
+ s->warn_kex = TRUE;
+ } else {
+ if (!preferred) preferred = k->name;
+ if (in_commasep_string(k->name, str, len))
+ ssh->kex = k;
+ }
+ if (ssh->kex)
+ break;
+ }
+ if (!ssh->kex) {
+ bombout(("Couldn't agree a key exchange algorithm (available: %s)",
+ str ? str : "(null)"));
+ crStop(0);
+ }
+ /*
+ * Note that the server's guess is considered wrong if it doesn't match
+ * the first algorithm in our list, even if it's still the algorithm
+ * we end up using.
+ */
+ s->guessok = first_in_commasep_string(preferred, str, len);
+ ssh_pkt_getstring(pktin, &str, &len); /* host key algorithms */
+ for (i = 0; i < lenof(hostkey_algs); i++) {
+ if (in_commasep_string(hostkey_algs[i]->name, str, len)) {
+ ssh->hostkey = hostkey_algs[i];
+ break;
+ }
+ }
+ s->guessok = s->guessok &&
+ first_in_commasep_string(hostkey_algs[0]->name, str, len);
+ ssh_pkt_getstring(pktin, &str, &len); /* client->server cipher */
+ for (i = 0; i < s->n_preferred_ciphers; i++) {
+ const struct ssh2_ciphers *c = s->preferred_ciphers[i];
+ if (!c) {
+ s->warn_cscipher = TRUE;
+ } else {
+ for (j = 0; j < c->nciphers; j++) {
+ if (in_commasep_string(c->list[j]->name, str, len)) {
+ s->cscipher_tobe = c->list[j];
+ break;
+ }
+ }
+ }
+ if (s->cscipher_tobe)
+ break;
+ }
+ if (!s->cscipher_tobe) {
+ bombout(("Couldn't agree a client-to-server cipher (available: %s)",
+ str ? str : "(null)"));
+ crStop(0);
+ }
+
+ ssh_pkt_getstring(pktin, &str, &len); /* server->client cipher */
+ for (i = 0; i < s->n_preferred_ciphers; i++) {
+ const struct ssh2_ciphers *c = s->preferred_ciphers[i];
+ if (!c) {
+ s->warn_sccipher = TRUE;
+ } else {
+ for (j = 0; j < c->nciphers; j++) {
+ if (in_commasep_string(c->list[j]->name, str, len)) {
+ s->sccipher_tobe = c->list[j];
+ break;
+ }
+ }
+ }
+ if (s->sccipher_tobe)
+ break;
+ }
+ if (!s->sccipher_tobe) {
+ bombout(("Couldn't agree a server-to-client cipher (available: %s)",
+ str ? str : "(null)"));
+ crStop(0);
+ }
+
+ ssh_pkt_getstring(pktin, &str, &len); /* client->server mac */
+ for (i = 0; i < s->nmacs; i++) {
+ if (in_commasep_string(s->maclist[i]->name, str, len)) {
+ s->csmac_tobe = s->maclist[i];
+ break;
+ }
+ }
+ ssh_pkt_getstring(pktin, &str, &len); /* server->client mac */
+ for (i = 0; i < s->nmacs; i++) {
+ if (in_commasep_string(s->maclist[i]->name, str, len)) {
+ s->scmac_tobe = s->maclist[i];
+ break;
+ }
+ }
+ ssh_pkt_getstring(pktin, &str, &len); /* client->server compression */
+ for (i = 0; i < lenof(compressions) + 1; i++) {
+ const struct ssh_compress *c =
+ i == 0 ? s->preferred_comp : compressions[i - 1];
+ if (in_commasep_string(c->name, str, len)) {
+ s->cscomp_tobe = c;
+ break;
+ }
+ }
+ ssh_pkt_getstring(pktin, &str, &len); /* server->client compression */
+ for (i = 0; i < lenof(compressions) + 1; i++) {
+ const struct ssh_compress *c =
+ i == 0 ? s->preferred_comp : compressions[i - 1];
+ if (in_commasep_string(c->name, str, len)) {
+ s->sccomp_tobe = c;
+ break;
+ }
+ }
+ ssh_pkt_getstring(pktin, &str, &len); /* client->server language */
+ ssh_pkt_getstring(pktin, &str, &len); /* server->client language */
+ s->ignorepkt = ssh2_pkt_getbool(pktin) && !s->guessok;
+
+ if (s->warn_kex) {
+ ssh_set_frozen(ssh, 1);
+ s->dlgret = askalg(ssh->frontend, "key-exchange algorithm",
+ ssh->kex->name,
+ ssh_dialog_callback, ssh);
+ if (s->dlgret < 0) {
+ do {
+ crReturn(0);
+ if (pktin) {
+ bombout(("Unexpected data from server while"
+ " waiting for user response"));
+ crStop(0);
+ }
+ } while (pktin || inlen > 0);
+ s->dlgret = ssh->user_response;
+ }
+ ssh_set_frozen(ssh, 0);
+ if (s->dlgret == 0) {
+ ssh->close_expected = TRUE;
+ ssh_closing((Plug)ssh, NULL, 0, 0);
+ crStop(0);
+ }
+ }
+
+ if (s->warn_cscipher) {
+ ssh_set_frozen(ssh, 1);
+ s->dlgret = askalg(ssh->frontend,
+ "client-to-server cipher",
+ s->cscipher_tobe->name,
+ ssh_dialog_callback, ssh);
+ if (s->dlgret < 0) {
+ do {
+ crReturn(0);
+ if (pktin) {
+ bombout(("Unexpected data from server while"
+ " waiting for user response"));
+ crStop(0);
+ }
+ } while (pktin || inlen > 0);
+ s->dlgret = ssh->user_response;
+ }
+ ssh_set_frozen(ssh, 0);
+ if (s->dlgret == 0) {
+ ssh->close_expected = TRUE;
+ ssh_closing((Plug)ssh, NULL, 0, 0);
+ crStop(0);
+ }
+ }
+
+ if (s->warn_sccipher) {
+ ssh_set_frozen(ssh, 1);
+ s->dlgret = askalg(ssh->frontend,
+ "server-to-client cipher",
+ s->sccipher_tobe->name,
+ ssh_dialog_callback, ssh);
+ if (s->dlgret < 0) {
+ do {
+ crReturn(0);
+ if (pktin) {
+ bombout(("Unexpected data from server while"
+ " waiting for user response"));
+ crStop(0);
+ }
+ } while (pktin || inlen > 0);
+ s->dlgret = ssh->user_response;
+ }
+ ssh_set_frozen(ssh, 0);
+ if (s->dlgret == 0) {
+ ssh->close_expected = TRUE;
+ ssh_closing((Plug)ssh, NULL, 0, 0);
+ crStop(0);
+ }
+ }
+
+ if (s->ignorepkt) /* first_kex_packet_follows */
+ crWaitUntil(pktin); /* Ignore packet */