X-Git-Url: https://git.distorted.org.uk/u/mdw/putty/blobdiff_plain/84328ddb72b558b47ac1e59f15c7fce1653bd550..b59743d5e8caf832964543fab86839220e72cc90:/ssh.c diff --git a/ssh.c b/ssh.c index 163b2ea3..0bd89a40 100644 --- a/ssh.c +++ b/ssh.c @@ -106,6 +106,7 @@ */ #define SSH2_PKTCTX_DHGROUP 0x0001 #define SSH2_PKTCTX_DHGEX 0x0002 +#define SSH2_PKTCTX_KEX_MASK 0x000F #define SSH2_PKTCTX_PUBLICKEY 0x0010 #define SSH2_PKTCTX_PASSWORD 0x0020 #define SSH2_PKTCTX_KBDINTER 0x0040 @@ -162,7 +163,7 @@ static const char *const ssh2_disconnect_reasons[] = { #define BUG_CHOKES_ON_RSA 8 #define BUG_SSH2_RSA_PADDING 16 #define BUG_SSH2_DERIVEKEY 32 -/* 64 was BUG_SSH2_DH_GEX, now spare */ +#define BUG_SSH2_REKEY 64 #define BUG_SSH2_PK_SESSIONID 128 #define translate(x) if (type == x) return #x @@ -359,6 +360,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, #define SSH1_BUFFER_LIMIT 32768 #define SSH_MAX_BACKLOG 32768 #define OUR_V2_WINSIZE 16384 +#define OUR_V2_MAXPKT 0x4000UL const static struct ssh_signkey *hostkey_algs[] = { &ssh_rsa, &ssh_dss }; @@ -520,15 +522,18 @@ struct ssh_portfwd { int type; unsigned sport, dport; char *saddr, *daddr; + char *sserv, *dserv; struct ssh_rportfwd *remote; int addressfamily; void *local; }; #define free_portfwd(pf) ( \ - ((pf) ? (sfree((pf)->saddr), sfree((pf)->daddr)) : (void)0 ), sfree(pf) ) + ((pf) ? (sfree((pf)->saddr), sfree((pf)->daddr), \ + sfree((pf)->sserv), sfree((pf)->dserv)) : (void)0 ), sfree(pf) ) struct Packet { long length; + long forcepad; /* Force padding to at least this length */ int type; unsigned long sequence; unsigned char *data; @@ -545,9 +550,9 @@ struct Packet { struct logblank_t *blanks; }; -static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, +static void ssh1_protocol(Ssh ssh, void *vin, int inlen, struct Packet *pktin); -static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen, +static void ssh2_protocol(Ssh ssh, void *vin, int inlen, struct Packet *pktin); static void ssh1_protocol_setup(Ssh ssh); static void ssh2_protocol_setup(Ssh ssh); @@ -558,12 +563,12 @@ static void ssh2_add_channel_data(struct ssh_channel *c, char *buf, int len); static void ssh_throttle_all(Ssh ssh, int enable, int bufsize); static void ssh2_set_window(struct ssh_channel *c, unsigned newwin); static int ssh_sendbuffer(void *handle); -static void ssh_do_close(Ssh ssh); +static int ssh_do_close(Ssh ssh, int notify_exit); static unsigned long ssh_pkt_getuint32(struct Packet *pkt); static int ssh2_pkt_getbool(struct Packet *pkt); static void ssh_pkt_getstring(struct Packet *pkt, char **p, int *length); static void ssh2_timer(void *ctx, long now); -static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, +static int do_ssh2_transport(Ssh ssh, void *vin, int inlen, struct Packet *pktin); struct rdpkt1_state_tag { @@ -639,6 +644,7 @@ struct ssh_tag { tree234 *channels; /* indexed by local id */ struct ssh_channel *mainchan; /* primary session channel */ int exitcode; + int close_expected; tree234 *rportfwds, *portfwds; @@ -683,7 +689,7 @@ struct ssh_tag { int overall_bufsize; int throttled_all; int v1_stdout_throttling; - int v2_outgoing_sequence; + unsigned long v2_outgoing_sequence; int ssh1_rdpkt_crstate; int ssh2_rdpkt_crstate; @@ -705,7 +711,7 @@ struct ssh_tag { /* ssh1 and ssh2 use this for different things, but both use it */ int protocol_initial_phase_done; - void (*protocol) (Ssh ssh, unsigned char *in, int inlen, + void (*protocol) (Ssh ssh, void *vin, int inlen, struct Packet *pkt); struct Packet *(*s_rdpkt) (Ssh ssh, unsigned char **data, int *datalen); @@ -748,6 +754,7 @@ struct ssh_tag { unsigned long max_data_size; int kex_in_progress; long next_rekey, last_rekey; + char *deferred_rekey_reason; /* points to STATIC string; don't free */ }; #define logevent(s) logevent(ssh->frontend, s) @@ -768,7 +775,7 @@ static void logeventf(Ssh ssh, const char *fmt, ...) #define bombout(msg) \ do { \ char *text = dupprintf msg; \ - ssh_do_close(ssh); \ + ssh_do_close(ssh, FALSE); \ logevent(text); \ connection_fatal(ssh->frontend, "%s", text); \ sfree(text); \ @@ -1566,6 +1573,7 @@ static struct Packet *ssh2_pkt_init(int pkt_type) { struct Packet *pkt = ssh_new_packet(); pkt->length = 5; + pkt->forcepad = 0; ssh2_pkt_addbyte(pkt, (unsigned char) pkt_type); return pkt; } @@ -1662,12 +1670,17 @@ static int ssh2_pkt_construct(Ssh ssh, struct Packet *pkt) /* * Add padding. At least four bytes, and must also bring total * length (minus MAC) up to a multiple of the block size. + * If pkt->forcepad is set, make sure the packet is at least that size + * after padding. */ cipherblk = ssh->cscipher ? ssh->cscipher->blksize : 8; /* block size */ cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */ padding = 4; + if (pkt->length + padding < pkt->forcepad) + padding = pkt->forcepad - pkt->length; padding += (cipherblk - (pkt->length + padding) % cipherblk) % cipherblk; + assert(padding <= 255); maclen = ssh->csmac ? ssh->csmac->len : 0; ssh2_pkt_ensure(pkt, pkt->length + padding + maclen); pkt->data[4] = padding; @@ -1735,8 +1748,7 @@ static void ssh2_pkt_send_noqueue(Ssh ssh, struct Packet *pkt) if (!ssh->kex_in_progress && ssh->max_data_size != 0 && ssh->outgoing_data_size > ssh->max_data_size) - do_ssh2_transport(ssh, "Initiating key re-exchange " - "(too much data sent)", -1, NULL); + do_ssh2_transport(ssh, "too much data sent", -1, NULL); ssh_free_packet(pkt); } @@ -1786,6 +1798,7 @@ static void ssh2_pkt_send(Ssh ssh, struct Packet *pkt) ssh2_pkt_send_noqueue(ssh, pkt); } +#if 0 /* disused */ /* * Either queue or defer a packet, depending on whether queueing is * set. @@ -1797,6 +1810,7 @@ static void ssh2_pkt_defer(Ssh ssh, struct Packet *pkt) else ssh2_pkt_defer_noqueue(ssh, pkt); } +#endif /* * Send the whole deferred data block constructed by @@ -1826,8 +1840,7 @@ static void ssh_pkt_defersend(Ssh ssh) if (!ssh->kex_in_progress && ssh->max_data_size != 0 && ssh->outgoing_data_size > ssh->max_data_size) - do_ssh2_transport(ssh, "Initiating key re-exchange " - "(too much data sent)", -1, NULL); + do_ssh2_transport(ssh, "too much data sent", -1, NULL); ssh->deferred_data_size = 0; } @@ -2134,6 +2147,19 @@ static void ssh_detect_bugs(Ssh ssh, char *vstring) ssh->remote_bugs |= BUG_SSH2_PK_SESSIONID; logevent("We believe remote version has SSH2 public-key-session-ID bug"); } + + if (ssh->cfg.sshbug_rekey2 == FORCE_ON || + (ssh->cfg.sshbug_rekey2 == AUTO && + (wc_match("OpenSSH_2.[0-4]*", imp) || + wc_match("OpenSSH_2.5.[0-3]*", imp) || + wc_match("Sun_SSH_1.0", imp) || + wc_match("Sun_SSH_1.0.1", imp)))) { + /* + * These versions have the SSH2 rekey bug. + */ + ssh->remote_bugs |= BUG_SSH2_REKEY; + logevent("We believe remote version has SSH2 rekey bug"); + } } /* @@ -2353,16 +2379,19 @@ static void ssh_gotdata(Ssh ssh, unsigned char *data, int datalen) crFinishV; } -static void ssh_do_close(Ssh ssh) +static int ssh_do_close(Ssh ssh, int notify_exit) { - int i; + int i, ret = 0; struct ssh_channel *c; ssh->state = SSH_STATE_CLOSED; if (ssh->s) { sk_close(ssh->s); ssh->s = NULL; - notify_remote_exit(ssh->frontend); + if (notify_exit) + notify_remote_exit(ssh->frontend); + else + ret = 1; } /* * Now we must shut down any port and X forwardings going @@ -2384,20 +2413,45 @@ static void ssh_do_close(Ssh ssh) sfree(c); } } + + return ret; +} + +static void ssh_log(Plug plug, int type, SockAddr addr, int port, + const char *error_msg, int error_code) +{ + Ssh ssh = (Ssh) plug; + char addrbuf[256], *msg; + + sk_getaddr(addr, addrbuf, lenof(addrbuf)); + + if (type == 0) + msg = dupprintf("Connecting to %s port %d", addrbuf, port); + else + msg = dupprintf("Failed to connect to %s: %s", addrbuf, error_msg); + + logevent(msg); } static int ssh_closing(Plug plug, const char *error_msg, int error_code, int calling_back) { Ssh ssh = (Ssh) plug; - ssh_do_close(ssh); + int need_notify = ssh_do_close(ssh, FALSE); + + if (!error_msg && !ssh->close_expected) { + error_msg = "Server unexpectedly closed network connection"; + } + if (error_msg) { /* A socket error has occurred. */ logevent(error_msg); connection_fatal(ssh->frontend, "%s", error_msg); } else { - /* Otherwise, the remote side closed the connection normally. */ + logevent("Server closed network connection"); } + if (need_notify) + notify_remote_exit(ssh->frontend); return 0; } @@ -2406,7 +2460,7 @@ static int ssh_receive(Plug plug, int urgent, char *data, int len) Ssh ssh = (Ssh) plug; ssh_gotdata(ssh, (unsigned char *)data, len); if (ssh->state == SSH_STATE_CLOSED) { - ssh_do_close(ssh); + ssh_do_close(ssh, TRUE); return 0; } return 1; @@ -2433,6 +2487,7 @@ static const char *connect_to_host(Ssh ssh, char *host, int port, char **realhost, int nodelay, int keepalive) { static const struct plug_function_table fn_table = { + ssh_log, ssh_closing, ssh_receive, ssh_sent, @@ -2467,11 +2522,6 @@ static const char *connect_to_host(Ssh ssh, char *host, int port, /* * Open socket. */ - { - char addrbuf[100]; - sk_getaddr(addr, addrbuf, 100); - logeventf(ssh, "Connecting to %s port %d", addrbuf, port); - } ssh->fn = &fn_table; ssh->s = new_connection(addr, *realhost, port, 0, 1, nodelay, keepalive, (Plug) ssh, &ssh->cfg); @@ -2831,8 +2881,11 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, } /* Warn about chosen cipher if necessary. */ - if (warn) + if (warn) { + sk_set_frozen(ssh->s, 1); askalg(ssh->frontend, "cipher", cipher_string); + sk_set_frozen(ssh->s, 0); + } } switch (s->cipher_type) { @@ -2904,6 +2957,7 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, * Terminate. */ logevent("No username provided. Abandoning session."); + ssh->close_expected = TRUE; ssh_closing((Plug)ssh, NULL, 0, 0); crStop(1); } @@ -3252,6 +3306,7 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, PKT_END); logevent("Unable to authenticate"); connection_fatal(ssh->frontend, "Unable to authenticate"); + ssh->close_expected = TRUE; ssh_closing((Plug)ssh, NULL, 0, 0); crStop(1); } @@ -3784,8 +3839,10 @@ static void ssh_setup_portfwd(Ssh ssh, const Config *cfg) pfrec = snew(struct ssh_portfwd); pfrec->type = type; pfrec->saddr = *saddr ? dupstr(saddr) : NULL; + pfrec->sserv = sserv ? dupstr(sports) : NULL; pfrec->sport = sport; pfrec->daddr = *host ? dupstr(host) : NULL; + pfrec->dserv = dserv ? dupstr(dports) : NULL; pfrec->dport = dport; pfrec->local = NULL; pfrec->remote = NULL; @@ -3882,14 +3939,22 @@ static void ssh_setup_portfwd(Ssh ssh, const Config *cfg) for (i = 0; (epf = index234(ssh->portfwds, i)) != NULL; i++) if (epf->status == CREATE) { char *sportdesc, *dportdesc; - sportdesc = dupprintf("%s%s%d", + sportdesc = dupprintf("%s%s%s%s%d%s", epf->saddr ? epf->saddr : "", epf->saddr ? ":" : "", - epf->sport); + epf->sserv ? epf->sserv : "", + epf->sserv ? "(" : "", + epf->sport, + epf->sserv ? ")" : ""); if (epf->type == 'D') { dportdesc = NULL; } else { - dportdesc = dupprintf("%s:%d", epf->daddr, epf->dport); + dportdesc = dupprintf("%s:%s%s%d%s", + epf->daddr, + epf->dserv ? epf->dserv : "", + epf->dserv ? "(" : "", + epf->dport, + epf->dserv ? ")" : ""); } if (epf->type == 'L') { @@ -4214,7 +4279,7 @@ static void ssh1_msg_channel_data(Ssh ssh, struct Packet *pktin) /* Data sent down one of our channels. */ int i = ssh_pkt_getuint32(pktin); char *p; - unsigned int len; + int len; struct ssh_channel *c; ssh_pkt_getstring(pktin, &p, &len); @@ -4294,6 +4359,7 @@ static void ssh1_smsg_exit_status(Ssh ssh, struct Packet *pktin) * encrypted packet, we close the session once * we've sent EXIT_CONFIRMATION. */ + ssh->close_expected = TRUE; ssh_closing((Plug)ssh, NULL, 0, 0); } @@ -4533,9 +4599,10 @@ static void ssh1_protocol_setup(Ssh ssh) ssh->packet_dispatch[SSH1_MSG_DEBUG] = ssh1_msg_debug; } -static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, +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; @@ -4586,6 +4653,28 @@ static int in_commasep_string(char *needle, char *haystack, int haylen) } /* + * 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; +} + + +/* * SSH2 key creation method. */ static void ssh2_mkkey(Ssh ssh, Bignum K, unsigned char *H, @@ -4613,9 +4702,10 @@ static void ssh2_mkkey(Ssh ssh, Bignum K, unsigned char *H, /* * Handle the SSH2 transport layer. */ -static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, +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; Bignum p, g, e, f, K; @@ -4637,7 +4727,7 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int n_preferred_ciphers; const struct ssh2_ciphers *preferred_ciphers[CIPHER_MAX]; const struct ssh_compress *preferred_comp; - int first_kex; + int got_session_id, activated_authconn; struct Packet *pktout; }; crState(do_ssh2_transport_state); @@ -4648,10 +4738,21 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, s->csmac_tobe = s->scmac_tobe = NULL; s->cscomp_tobe = s->sccomp_tobe = NULL; - s->first_kex = 1; + 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; + int i, j, commalist_started; + /* * Set up the preferred key exchange. (NULL => warn below here) */ @@ -4679,10 +4780,7 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, break; } } - } - { - int i; /* * Set up the preferred ciphers. (NULL => warn below here) */ @@ -4712,27 +4810,14 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, break; } } - } - /* - * Set up preferred compression. - */ - if (ssh->cfg.compression) - s->preferred_comp = &ssh_zlib; - else - s->preferred_comp = &ssh_comp_none; - - /* - * 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: - { - int i, j, commalist_started; + /* + * 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 @@ -4857,7 +4942,7 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, */ { char *str; - int i, j, len; + int i, j, len, guessok; if (pktin->type != SSH2_MSG_KEXINIT) { bombout(("expected key exchange packet from server")); @@ -4882,9 +4967,12 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, ssh->kex = k; } if (ssh->kex) { - if (s->warn) + if (s->warn) { + sk_set_frozen(ssh->s, 1); askalg(ssh->frontend, "key-exchange algorithm", ssh->kex->name); + sk_set_frozen(ssh->s, 0); + } break; } } @@ -4893,6 +4981,13 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, 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. + */ + guessok = + first_in_commasep_string(s->preferred_kex[0]->name, 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)) { @@ -4900,6 +4995,8 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, break; } } + guessok = guessok && + first_in_commasep_string(hostkey_algs[0]->name, str, len); ssh_pkt_getstring(pktin, &str, &len); /* client->server cipher */ s->warn = 0; for (i = 0; i < s->n_preferred_ciphers; i++) { @@ -4915,9 +5012,12 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, } } if (s->cscipher_tobe) { - if (s->warn) + if (s->warn) { + sk_set_frozen(ssh->s, 1); askalg(ssh->frontend, "client-to-server cipher", s->cscipher_tobe->name); + sk_set_frozen(ssh->s, 0); + } break; } } @@ -4942,9 +5042,12 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, } } if (s->sccipher_tobe) { - if (s->warn) + if (s->warn) { + sk_set_frozen(ssh->s, 1); askalg(ssh->frontend, "server-to-client cipher", s->sccipher_tobe->name); + sk_set_frozen(ssh->s, 0); + } break; } } @@ -4986,6 +5089,10 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, break; } } + ssh_pkt_getstring(pktin, &str, &len); /* client->server language */ + ssh_pkt_getstring(pktin, &str, &len); /* server->client language */ + if (ssh2_pkt_getbool(pktin) && !guessok) /* first_kex_packet_follows */ + crWaitUntil(pktin); /* Ignore packet */ } /* @@ -5101,10 +5208,12 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, */ s->keystr = ssh->hostkey->fmtkey(s->hkey); s->fingerprint = ssh->hostkey->fingerprint(s->hkey); + sk_set_frozen(ssh->s, 1); verify_ssh_host_key(ssh->frontend, ssh->savedhost, ssh->savedport, ssh->hostkey->keytype, s->keystr, s->fingerprint); - if (s->first_kex) { /* don't bother logging this in rekeys */ + sk_set_frozen(ssh->s, 0); + if (!s->got_session_id) { /* don't bother logging this in rekeys */ logevent("Host key fingerprint is:"); logevent(s->fingerprint); } @@ -5117,9 +5226,11 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, * the session id, used in session key construction and * authentication. */ - if (s->first_kex) + if (!s->got_session_id) { memcpy(ssh->v2_session_id, s->exchange_hash, sizeof(s->exchange_hash)); + s->got_session_id = TRUE; + } /* * Send SSH2_MSG_NEWKEYS. @@ -5237,14 +5348,25 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, } /* - * Key exchange is over. Schedule a timer for our next rekey. + * Key exchange is over. Loop straight back round if we have a + * deferred rekey reason. + */ + if (ssh->deferred_rekey_reason) { + logevent(ssh->deferred_rekey_reason); + pktin = NULL; + ssh->deferred_rekey_reason = NULL; + goto begin_key_exchange; + } + + /* + * Otherwise, schedule a timer for our next rekey. */ ssh->kex_in_progress = FALSE; ssh->last_rekey = GETTICKCOUNT(); if (ssh->cfg.ssh_rekey_time != 0) ssh->next_rekey = schedule_timer(ssh->cfg.ssh_rekey_time*60*TICKSPERSEC, ssh2_timer, ssh); - + /* * If this is the first key exchange phase, we must pass the * SSH2_MSG_NEWKEYS packet to the next layer, not because it @@ -5253,10 +5375,10 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, * exchange phases, we don't pass SSH2_MSG_NEWKEYS on, because * it would only confuse the layer above. */ - if (!s->first_kex) { + if (s->activated_authconn) { crReturn(1); } - s->first_kex = 0; + s->activated_authconn = TRUE; /* * Now we're encrypting. Begin returning 1 to the protocol main @@ -5271,12 +5393,34 @@ static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, */ while (!((pktin && pktin->type == SSH2_MSG_KEXINIT) || (!pktin && inlen == -1))) { + wait_for_rekey: crReturn(1); } if (pktin) { logevent("Server initiated key re-exchange"); } else { - logevent((char *)in); + /* + * Special case: if the server bug is set that doesn't + * allow rekeying, we give a different log message and + * continue waiting. (If such a server _initiates_ a rekey, + * we process it anyway!) + */ + if ((ssh->remote_bugs & BUG_SSH2_REKEY)) { + logeventf(ssh, "Server bug prevents key re-exchange (%s)", + (char *)in); + /* Reset the counters, so that at least this message doesn't + * hit the event log _too_ often. */ + ssh->outgoing_data_size = 0; + ssh->incoming_data_size = 0; + if (ssh->cfg.ssh_rekey_time != 0) { + ssh->next_rekey = + schedule_timer(ssh->cfg.ssh_rekey_time*60*TICKSPERSEC, + ssh2_timer, ssh); + } + goto wait_for_rekey; /* this is utterly horrid */ + } else { + logeventf(ssh, "Initiating key re-exchange (%s)", (char *)in); + } } goto begin_key_exchange; @@ -5341,7 +5485,14 @@ static void ssh2_set_window(struct ssh_channel *c, unsigned newwin) if (c->closes != 0) return; - if (newwin > c->v.v2.locwindow) { + /* + * Only send a WINDOW_ADJUST if there's significantly more window + * available than the other end thinks there is. This saves us + * sending a WINDOW_ADJUST for every character in a shell session. + * + * "Significant" is arbitrarily defined as half the window size. + */ + if (newwin > c->v.v2.locwindow * 2) { struct Packet *pktout; pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_WINDOW_ADJUST); @@ -5364,7 +5515,7 @@ static void ssh2_msg_channel_window_adjust(Ssh ssh, struct Packet *pktin) static void ssh2_msg_channel_data(Ssh ssh, struct Packet *pktin) { char *data; - unsigned int length; + int length; unsigned i = ssh_pkt_getuint32(pktin); struct ssh_channel *c; c = find234(ssh->channels, &i, ssh_channelfind); @@ -5531,6 +5682,7 @@ static void ssh2_msg_channel_close(Ssh ssh, struct Packet *pktin) ssh2_pkt_addstring(s->pktout, "en"); /* language tag */ ssh2_pkt_send_noqueue(ssh, s->pktout); #endif + ssh->close_expected = TRUE; ssh_closing((Plug)ssh, NULL, 0, 0); } } @@ -5631,6 +5783,7 @@ static void ssh2_msg_channel_request(Ssh ssh, struct Packet *pktin) ssh2_pkt_addstring(pktout, "en"); /* language tag */ ssh2_pkt_send_noqueue(ssh, pktout); connection_fatal(ssh->frontend, "%s", buf); + ssh->close_expected = TRUE; ssh_closing((Plug)ssh, NULL, 0, 0); return; } @@ -5681,7 +5834,7 @@ static void ssh2_msg_channel_request(Ssh ssh, struct Packet *pktin) if (q >= 0 && q+4 <= len) { \ q = q + 4 + GET_32BIT(p+q); \ if (q >= 0 && q+4 <= len && \ - (q = q + 4 + GET_32BIT(p+q)) && q == len) \ + ((q = q + 4 + GET_32BIT(p+q))!= 0) && q == len) \ result = TRUE; \ } \ } while(0) @@ -5874,7 +6027,7 @@ static void ssh2_msg_channel_open(Ssh ssh, struct Packet *pktin) ssh2_pkt_adduint32(pktout, c->remoteid); ssh2_pkt_adduint32(pktout, c->localid); ssh2_pkt_adduint32(pktout, c->v.v2.locwindow); - ssh2_pkt_adduint32(pktout, 0x4000UL); /* our max pkt size */ + ssh2_pkt_adduint32(pktout, OUR_V2_MAXPKT); /* our max pkt size */ ssh2_pkt_send(ssh, pktout); } } @@ -5901,8 +6054,8 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET } type; int gotit, need_pw, can_pubkey, can_passwd, can_keyb_inter; - int tried_pubkey_config, tried_agent, tried_keyb_inter; - int kbd_inter_running; + int tried_pubkey_config, tried_agent; + int kbd_inter_running, kbd_inter_refused; int we_are_in; int num_prompts, curr_prompt, echo; char username[100]; @@ -5984,6 +6137,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, * Terminate. */ logevent("No username provided. Abandoning session."); + ssh->close_expected = TRUE; ssh_closing((Plug)ssh, NULL, 0, 0); crStopV; } @@ -6031,8 +6185,8 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, s->tried_pubkey_config = FALSE; s->tried_agent = FALSE; - s->tried_keyb_inter = FALSE; s->kbd_inter_running = FALSE; + s->kbd_inter_refused = FALSE; /* Load the pub half of ssh->cfg.keyfile so we notice if it's in Pageant */ if (!filename_is_null(ssh->cfg.keyfile)) { int keytype; @@ -6099,6 +6253,10 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, */ if (!s->gotit) s->curr_prompt = 0; + } else if (pktin->type == SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ) { + /* FIXME: perhaps we should support this? */ + bombout(("PASSWD_CHANGEREQ not yet supported")); + crStopV; } else if (pktin->type != SSH2_MSG_USERAUTH_FAILURE) { bombout(("Strange packet received during authentication: type %d", pktin->type)); @@ -6423,10 +6581,10 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, } } - if (!s->method && s->can_keyb_inter && !s->tried_keyb_inter) { + if (!s->method && s->can_keyb_inter && !s->kbd_inter_refused && + !s->kbd_inter_running) { s->method = AUTH_KEYBOARD_INTERACTIVE; s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE; - s->tried_keyb_inter = TRUE; ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK; ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER; @@ -6445,6 +6603,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, s->gotit = TRUE; logevent("Keyboard-interactive authentication refused"); s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET; + s->kbd_inter_refused = TRUE; /* don't try it again */ continue; } @@ -6455,7 +6614,6 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, if (s->kbd_inter_running) { s->method = AUTH_KEYBOARD_INTERACTIVE; s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE; - s->tried_keyb_inter = TRUE; ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK; ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER; @@ -6541,6 +6699,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, logevent("Unable to authenticate"); connection_fatal(ssh->frontend, "Unable to authenticate"); + ssh->close_expected = TRUE; ssh_closing((Plug)ssh, NULL, 0, 0); crStopV; } @@ -6643,20 +6802,16 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, } } else if (s->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. + * We pad out the password packet to 256 bytes to make + * it harder for an attacker to find the length of the + * user's password. * - * 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 + * Anyone using a password longer than 256 bytes + * probably doesn't have much to worry about from * people who find out how long their password is! */ s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST); + s->pktout->forcepad = 256; ssh2_pkt_addstring(s->pktout, s->username); ssh2_pkt_addstring(s->pktout, "ssh-connection"); /* service requested */ ssh2_pkt_addstring(s->pktout, "password"); @@ -6665,46 +6820,13 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, ssh2_pkt_addstring(s->pktout, s->password); memset(s->password, 0, sizeof(s->password)); end_log_omission(ssh, s->pktout); - ssh2_pkt_defer(ssh, s->pktout); - /* - * 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 (ssh->cscipher) { - int stringlen, i; - - stringlen = (256 - ssh->deferred_len); - stringlen += ssh->cscipher->blksize - 1; - stringlen -= (stringlen % ssh->cscipher->blksize); - if (ssh->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 -= - ssh->cscomp->disable_compression(ssh->cs_comp_ctx); - } - s->pktout = ssh2_pkt_init(SSH2_MSG_IGNORE); - ssh2_pkt_addstring_start(s->pktout); - for (i = 0; i < stringlen; i++) { - char c = (char) random_byte(); - ssh2_pkt_addstring_data(s->pktout, &c, 1); - } - ssh2_pkt_defer(ssh, s->pktout); - } - ssh_pkt_defersend(ssh); + ssh2_pkt_send(ssh, s->pktout); logevent("Sent password"); s->type = AUTH_TYPE_PASSWORD; } else if (s->method == AUTH_KEYBOARD_INTERACTIVE) { if (s->curr_prompt == 0) { s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_INFO_RESPONSE); + s->pktout->forcepad = 256; ssh2_pkt_adduint32(s->pktout, s->num_prompts); } if (s->need_pw) { /* only add pw if we just got one! */ @@ -6739,6 +6861,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, " methods available"); ssh2_pkt_addstring(s->pktout, "en"); /* language tag */ ssh2_pkt_send_noqueue(ssh, s->pktout); + ssh->close_expected = TRUE; ssh_closing((Plug)ssh, NULL, 0, 0); crStopV; } @@ -6774,7 +6897,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, ssh2_pkt_adduint32(s->pktout, ssh->mainchan->localid); ssh->mainchan->v.v2.locwindow = OUR_V2_WINSIZE; ssh2_pkt_adduint32(s->pktout, ssh->mainchan->v.v2.locwindow);/* our window size */ - ssh2_pkt_adduint32(s->pktout, 0x4000UL); /* our max pkt size */ + ssh2_pkt_adduint32(s->pktout, OUR_V2_MAXPKT); /* our max pkt size */ ssh2_pkt_send(ssh, s->pktout); crWaitUntilV(pktin); if (pktin->type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) { @@ -7246,14 +7369,14 @@ static void ssh2_timer(void *ctx, long now) if (!ssh->kex_in_progress && ssh->cfg.ssh_rekey_time != 0 && now - ssh->next_rekey >= 0) { - do_ssh2_transport(ssh, "Initiating key re-exchange (timeout)", - -1, NULL); + do_ssh2_transport(ssh, "timeout", -1, NULL); } } -static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen, +static void ssh2_protocol(Ssh ssh, void *vin, int inlen, struct Packet *pktin) { + unsigned char *in = (unsigned char *)vin; if (ssh->state == SSH_STATE_CLOSED) return; @@ -7262,8 +7385,7 @@ static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen, if (!ssh->kex_in_progress && ssh->max_data_size != 0 && ssh->incoming_data_size > ssh->max_data_size) - do_ssh2_transport(ssh, "Initiating key re-exchange " - "(too much data received)", -1, NULL); + do_ssh2_transport(ssh, "too much data received", -1, NULL); } if (pktin && ssh->packet_dispatch[pktin->type]) { @@ -7322,6 +7444,7 @@ static const char *ssh_init(void *frontend_handle, void **backend_handle, ssh->kex_ctx = NULL; ssh->hostkey = NULL; ssh->exitcode = -1; + ssh->close_expected = FALSE; ssh->state = SSH_STATE_PREPACKET; ssh->size_needed = FALSE; ssh->eof_needed = FALSE; @@ -7354,6 +7477,7 @@ static const char *ssh_init(void *frontend_handle, void **backend_handle, ssh->queuelen = ssh->queuesize = 0; ssh->queueing = FALSE; ssh->qhead = ssh->qtail = NULL; + ssh->deferred_rekey_reason = NULL; *backend_handle = ssh; @@ -7476,7 +7600,7 @@ static void ssh_free(void *handle) ssh->crcda_ctx = NULL; } if (ssh->s) - ssh_do_close(ssh); + ssh_do_close(ssh, TRUE); expire_timer_context(ssh); if (ssh->pinger) pinger_free(ssh->pinger); @@ -7491,7 +7615,7 @@ static void ssh_free(void *handle) static void ssh_reconfig(void *handle, Config *cfg) { Ssh ssh = (Ssh) handle; - char *rekeying = NULL; + char *rekeying = NULL, rekey_mandatory = FALSE; unsigned long old_max_data_size; pinger_reconfig(ssh->pinger, &ssh->cfg, cfg); @@ -7503,7 +7627,7 @@ static void ssh_reconfig(void *handle, Config *cfg) long now = GETTICKCOUNT(); if (new_next - now < 0) { - rekeying = "Initiating key re-exchange (timeout shortened)"; + rekeying = "timeout shortened"; } else { ssh->next_rekey = schedule_timer(new_next - now, ssh2_timer, ssh); } @@ -7515,14 +7639,30 @@ static void ssh_reconfig(void *handle, Config *cfg) ssh->max_data_size != 0) { if (ssh->outgoing_data_size > ssh->max_data_size || ssh->incoming_data_size > ssh->max_data_size) - rekeying = "Initiating key re-exchange (data limit lowered)"; + rekeying = "data limit lowered"; + } + + if (ssh->cfg.compression != cfg->compression) { + rekeying = "compression setting changed"; + rekey_mandatory = TRUE; } - if (rekeying && !ssh->kex_in_progress) { - do_ssh2_transport(ssh, rekeying, -1, NULL); + if (ssh->cfg.ssh2_des_cbc != cfg->ssh2_des_cbc || + memcmp(ssh->cfg.ssh_cipherlist, cfg->ssh_cipherlist, + sizeof(ssh->cfg.ssh_cipherlist))) { + rekeying = "cipher settings changed"; + rekey_mandatory = TRUE; } ssh->cfg = *cfg; /* STRUCTURE COPY */ + + if (rekeying) { + if (!ssh->kex_in_progress) { + do_ssh2_transport(ssh, rekeying, -1, NULL); + } else if (rekey_mandatory) { + ssh->deferred_rekey_reason = rekeying; + } + } } /* @@ -7723,8 +7863,7 @@ static void ssh_special(void *handle, Telnet_Special code) } } else if (code == TS_REKEY) { if (!ssh->kex_in_progress && ssh->version == 2) { - do_ssh2_transport(ssh, "Initiating key re-exchange at" - " user request", -1, NULL); + do_ssh2_transport(ssh, "at user request", -1, NULL); } } else if (code == TS_BRK) { if (ssh->state == SSH_STATE_CLOSED @@ -7832,7 +7971,7 @@ void ssh_send_port_open(void *channel, char *hostname, int port, char *org) ssh2_pkt_adduint32(pktout, c->localid); c->v.v2.locwindow = OUR_V2_WINSIZE; ssh2_pkt_adduint32(pktout, c->v.v2.locwindow);/* our window size */ - ssh2_pkt_adduint32(pktout, 0x4000UL); /* our max pkt size */ + ssh2_pkt_adduint32(pktout, OUR_V2_MAXPKT); /* our max pkt size */ ssh2_pkt_addstring(pktout, hostname); ssh2_pkt_adduint32(pktout, port); /*