X-Git-Url: https://git.distorted.org.uk/u/mdw/putty/blobdiff_plain/aacc46fab3288bb9ac32c5d50ccfb9c3ecbfd95d..HEAD:/ssh.c diff --git a/ssh.c b/ssh.c index 30ee4ba8..9eed54dc 100644 --- a/ssh.c +++ b/ssh.c @@ -460,14 +460,14 @@ struct Packet; static struct Packet *ssh1_pkt_init(int pkt_type); static struct Packet *ssh2_pkt_init(int pkt_type); static void ssh_pkt_ensure(struct Packet *, int length); -static void ssh_pkt_adddata(struct Packet *, void *data, int len); +static void ssh_pkt_adddata(struct Packet *, const void *data, int len); static void ssh_pkt_addbyte(struct Packet *, unsigned char value); static void ssh2_pkt_addbool(struct Packet *, unsigned char value); static void ssh_pkt_adduint32(struct Packet *, unsigned long value); static void ssh_pkt_addstring_start(struct Packet *); -static void ssh_pkt_addstring_str(struct Packet *, char *data); -static void ssh_pkt_addstring_data(struct Packet *, char *data, int len); -static void ssh_pkt_addstring(struct Packet *, char *data); +static void ssh_pkt_addstring_str(struct Packet *, const char *data); +static void ssh_pkt_addstring_data(struct Packet *, const char *data, int len); +static void ssh_pkt_addstring(struct Packet *, const char *data); static unsigned char *ssh2_mpint_fmt(Bignum b, int *len); static void ssh1_pkt_addmp(struct Packet *, Bignum b); static void ssh2_pkt_addmp(struct Packet *, Bignum b); @@ -1449,7 +1449,8 @@ static struct Packet *ssh2_rdpkt(Ssh ssh, unsigned char **data, int *datalen) /* See if that gives us a valid packet. */ if (ssh->scmac->verresult(ssh->sc_mac_ctx, st->pktin->data + st->packetlen) && - (st->len = GET_32BIT(st->pktin->data)) + 4 == st->packetlen) + ((st->len = toint(GET_32BIT(st->pktin->data))) == + st->packetlen-4)) break; if (st->packetlen >= OUR_V2_PACKETLIMIT) { bombout(("No valid incoming packet found")); @@ -1482,7 +1483,7 @@ static struct Packet *ssh2_rdpkt(Ssh ssh, unsigned char **data, int *datalen) /* * Now get the length figure. */ - st->len = GET_32BIT(st->pktin->data); + st->len = toint(GET_32BIT(st->pktin->data)); /* * _Completely_ silly lengths should be stomped on before they @@ -1828,7 +1829,7 @@ static void ssh_pkt_ensure(struct Packet *pkt, int length) if (body) pkt->body = pkt->data + offset; } } -static void ssh_pkt_adddata(struct Packet *pkt, void *data, int len) +static void ssh_pkt_adddata(struct Packet *pkt, const void *data, int len) { if (pkt->logmode != PKTLOG_EMIT) { pkt->nblanks++; @@ -1862,17 +1863,18 @@ static void ssh_pkt_addstring_start(struct Packet *pkt) ssh_pkt_adduint32(pkt, 0); pkt->savedpos = pkt->length; } -static void ssh_pkt_addstring_str(struct Packet *pkt, char *data) +static void ssh_pkt_addstring_str(struct Packet *pkt, const char *data) { ssh_pkt_adddata(pkt, data, strlen(data)); PUT_32BIT(pkt->data + pkt->savedpos - 4, pkt->length - pkt->savedpos); } -static void ssh_pkt_addstring_data(struct Packet *pkt, char *data, int len) +static void ssh_pkt_addstring_data(struct Packet *pkt, const char *data, + int len) { ssh_pkt_adddata(pkt, data, len); PUT_32BIT(pkt->data + pkt->savedpos - 4, pkt->length - pkt->savedpos); } -static void ssh_pkt_addstring(struct Packet *pkt, char *data) +static void ssh_pkt_addstring(struct Packet *pkt, const char *data) { ssh_pkt_addstring_start(pkt); ssh_pkt_addstring_str(pkt, data); @@ -2313,7 +2315,7 @@ static void ssh_pkt_getstring(struct Packet *pkt, char **p, int *length) *length = 0; if (pkt->length - pkt->savedpos < 4) return; - len = GET_32BIT(pkt->body + pkt->savedpos); + len = toint(GET_32BIT(pkt->body + pkt->savedpos)); if (len < 0) return; *length = len; @@ -2397,7 +2399,7 @@ static void ssh2_add_sigblob(Ssh ssh, struct Packet *pkt, * See if this is in fact an ssh-rsa signature and a buggy * server; otherwise we can just do this the easy way. */ - if ((ssh->remote_bugs & BUG_SSH2_RSA_PADDING) && + if ((ssh->remote_bugs & BUG_SSH2_RSA_PADDING) && pkblob_len > 4+7+4 && (GET_32BIT(pkblob) == 7 && !memcmp(pkblob+4, "ssh-rsa", 7))) { int pos, len, siglen; @@ -2406,8 +2408,15 @@ static void ssh2_add_sigblob(Ssh ssh, struct Packet *pkt, */ pos = 4+7; /* skip over "ssh-rsa" */ - pos += 4 + GET_32BIT(pkblob+pos); /* skip over exponent */ - len = GET_32BIT(pkblob+pos); /* find length of modulus */ + len = toint(GET_32BIT(pkblob+pos)); /* get length of exponent */ + if (len < 0 || len > pkblob_len - pos - 4) + goto give_up; + pos += 4 + len; /* skip over exponent */ + if (pkblob_len - pos < 4) + goto give_up; + len = toint(GET_32BIT(pkblob+pos)); /* find length of modulus */ + if (len < 0 || len > pkblob_len - pos - 4) + goto give_up; pos += 4; /* find modulus itself */ while (len > 0 && pkblob[pos] == 0) len--, pos++; @@ -2417,7 +2426,11 @@ static void ssh2_add_sigblob(Ssh ssh, struct Packet *pkt, * Now find the signature integer. */ pos = 4+7; /* skip over "ssh-rsa" */ - siglen = GET_32BIT(sigblob+pos); + if (sigblob_len < pos+4) + goto give_up; + siglen = toint(GET_32BIT(sigblob+pos)); + if (siglen != sigblob_len - pos - 4) + goto give_up; /* debug(("signature length is %d\n", siglen)); */ if (len != siglen) { @@ -2439,7 +2452,10 @@ static void ssh2_add_sigblob(Ssh ssh, struct Packet *pkt, return; } - /* Otherwise fall through and do it the easy way. */ + /* Otherwise fall through and do it the easy way. We also come + * here as a fallback if we discover above that the key blob + * is misformatted in some way. */ + give_up:; } ssh2_pkt_addstring_start(pkt); @@ -3677,7 +3693,12 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, if (s->response && s->responselen >= 5 && s->response[4] == SSH1_AGENT_RSA_IDENTITIES_ANSWER) { s->p = s->response + 5; - s->nkeys = GET_32BIT(s->p); + s->nkeys = toint(GET_32BIT(s->p)); + if (s->nkeys < 0) { + logeventf(ssh, "Pageant reported negative key count %d", + s->nkeys); + s->nkeys = 0; + } s->p += 4; logeventf(ssh, "Pageant has %d SSH-1 keys", s->nkeys); for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) { @@ -3687,22 +3708,23 @@ static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int n, ok = FALSE; do { /* do while (0) to make breaking easy */ n = ssh1_read_bignum - (s->p, s->responselen-(s->p-s->response), + (s->p, toint(s->responselen-(s->p-s->response)), &s->key.exponent); if (n < 0) break; s->p += n; n = ssh1_read_bignum - (s->p, s->responselen-(s->p-s->response), + (s->p, toint(s->responselen-(s->p-s->response)), &s->key.modulus); if (n < 0) - break; + break; s->p += n; if (s->responselen - (s->p-s->response) < 4) break; - s->commentlen = GET_32BIT(s->p); + s->commentlen = toint(GET_32BIT(s->p)); s->p += 4; - if (s->responselen - (s->p-s->response) < + if (s->commentlen < 0 || + toint(s->responselen - (s->p-s->response)) < s->commentlen) break; s->commentp = (char *)s->p; @@ -4848,14 +4870,11 @@ static void ssh1_msg_port_open(Ssh ssh, struct Packet *pktin) { /* Remote side is trying to open a channel to talk to a * forwarded port. Give them back a local channel number. */ - struct ssh_channel *c; struct ssh_rportfwd pf, *pfp; int remoteid; int hostsize, port; char *host; const char *e; - c = snew(struct ssh_channel); - c->ssh = ssh; remoteid = ssh_pkt_getuint32(pktin); ssh_pkt_getstring(pktin, &host, &hostsize); @@ -4874,6 +4893,9 @@ static void ssh1_msg_port_open(Ssh ssh, struct Packet *pktin) send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE, PKT_INT, remoteid, PKT_END); } else { + struct ssh_channel *c = snew(struct ssh_channel); + c->ssh = ssh; + logeventf(ssh, "Received remote port open request for %s:%d", pf.dhost, port); e = pfd_newconnect(&c->u.pfd.s, pf.dhost, port, @@ -5888,6 +5910,16 @@ static void do_ssh2_transport(Ssh ssh, void *vin, int inlen, ssh_pkt_getstring(pktin, &str, &len); /* server->client language */ s->ignorepkt = ssh2_pkt_getbool(pktin) && !s->guessok; + ssh->exhash = ssh->kex->hash->init(); + hash_string(ssh->kex->hash, ssh->exhash, ssh->v_c, strlen(ssh->v_c)); + hash_string(ssh->kex->hash, ssh->exhash, ssh->v_s, strlen(ssh->v_s)); + hash_string(ssh->kex->hash, ssh->exhash, + s->our_kexinit, s->our_kexinitlen); + sfree(s->our_kexinit); + if (pktin->length > 5) + hash_string(ssh->kex->hash, ssh->exhash, + pktin->data + 5, pktin->length - 5); + if (s->warn_kex) { ssh_set_frozen(ssh, 1); s->dlgret = askalg(ssh->frontend, "key-exchange algorithm", @@ -5962,16 +5994,6 @@ static void do_ssh2_transport(Ssh ssh, void *vin, int inlen, } } - ssh->exhash = ssh->kex->hash->init(); - hash_string(ssh->kex->hash, ssh->exhash, ssh->v_c, strlen(ssh->v_c)); - hash_string(ssh->kex->hash, ssh->exhash, ssh->v_s, strlen(ssh->v_s)); - hash_string(ssh->kex->hash, ssh->exhash, - s->our_kexinit, s->our_kexinitlen); - sfree(s->our_kexinit); - if (pktin->length > 5) - hash_string(ssh->kex->hash, ssh->exhash, - pktin->data + 5, pktin->length - 5); - if (s->ignorepkt) /* first_kex_packet_follows */ crWaitUntilV(pktin); /* Ignore packet */ } @@ -7073,6 +7095,15 @@ static void ssh2_msg_channel_close(Ssh ssh, struct Packet *pktin) } /* + * Abandon any buffered data we still wanted to send to this + * channel. Receiving a CHANNEL_CLOSE is an indication that + * the server really wants to get on and _destroy_ this + * channel, and it isn't going to send us any further + * WINDOW_ADJUSTs to permit us to send pending stuff. + */ + bufchain_clear(&c->v.v2.outbuffer); + + /* * Send outgoing EOF. */ sshfwd_write_eof(c); @@ -7193,16 +7224,18 @@ static void ssh2_msg_channel_request(Ssh ssh, struct Packet *pktin) is_int = FALSE; } else { int maybe_int = FALSE, maybe_str = FALSE; -#define CHECK_HYPOTHESIS(offset, result) \ - do { \ - long q = offset; \ - if (q >= 0 && q+4 <= len) { \ - q = q + 4 + GET_32BIT(p+q); \ - if (q >= 0 && q+4 <= len && \ - ((q = q + 4 + GET_32BIT(p+q))!= 0) && q == len) \ - result = TRUE; \ - } \ - } while(0) +#define CHECK_HYPOTHESIS(offset, result) \ + do \ + { \ + int q = toint(offset); \ + if (q >= 0 && q+4 <= len) { \ + q = toint(q + 4 + GET_32BIT(p+q)); \ + if (q >= 0 && q+4 <= len && \ + ((q = toint(q + 4 + GET_32BIT(p+q))) != 0) && \ + q == len) \ + result = TRUE; \ + } \ + } while(0) CHECK_HYPOTHESIS(4+1, maybe_int); CHECK_HYPOTHESIS(4+num+1, maybe_str); #undef CHECK_HYPOTHESIS @@ -7520,7 +7553,9 @@ static void ssh2_setup_x11(struct ssh_channel *c, struct Packet *pktin, ssh2_pkt_adduint32(pktout, ssh->x11disp->screennum); ssh2_pkt_send(ssh, pktout); - crWaitUntilV(pktin); + /* Wait to be called back with either a response packet, or NULL + * meaning clean up and free our data */ + crReturnV; if (pktin) { if (pktin->type == SSH2_MSG_CHANNEL_SUCCESS) { @@ -7550,7 +7585,9 @@ static void ssh2_setup_agent(struct ssh_channel *c, struct Packet *pktin, ssh2_setup_agent, s); ssh2_pkt_send(ssh, pktout); - crWaitUntilV(pktin); + /* Wait to be called back with either a response packet, or NULL + * meaning clean up and free our data */ + crReturnV; if (pktin) { if (pktin->type == SSH2_MSG_CHANNEL_SUCCESS) { @@ -7597,7 +7634,9 @@ static void ssh2_setup_pty(struct ssh_channel *c, struct Packet *pktin, ssh2_pkt_send(ssh, pktout); ssh->state = SSH_STATE_INTERMED; - crWaitUntilV(pktin); + /* Wait to be called back with either a response packet, or NULL + * meaning clean up and free our data */ + crReturnV; if (pktin) { if (pktin->type == SSH2_MSG_CHANNEL_SUCCESS) { @@ -7655,7 +7694,9 @@ static void ssh2_setup_env(struct ssh_channel *c, struct Packet *pktin, s->env_left = s->num_env; while (s->env_left > 0) { - crWaitUntilV(pktin); + /* Wait to be called back with either a response packet, + * or NULL meaning clean up and free our data */ + crReturnV; if (!pktin) goto out; if (pktin->type == SSH2_MSG_CHANNEL_SUCCESS) s->env_ok++; @@ -7896,13 +7937,53 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int keyi; unsigned char *p; p = s->agent_response + 5; - s->nkeys = GET_32BIT(p); + s->nkeys = toint(GET_32BIT(p)); + + /* + * Vet the Pageant response to ensure that the key + * count and blob lengths make sense. + */ + if (s->nkeys < 0) { + logeventf(ssh, "Pageant response contained a negative" + " key count %d", s->nkeys); + s->nkeys = 0; + goto done_agent_query; + } else { + unsigned char *q = p + 4; + int lenleft = s->agent_responselen - 5 - 4; + + for (keyi = 0; keyi < s->nkeys; keyi++) { + int bloblen, commentlen; + if (lenleft < 4) { + logeventf(ssh, "Pageant response was truncated"); + s->nkeys = 0; + goto done_agent_query; + } + bloblen = toint(GET_32BIT(q)); + if (bloblen < 0 || bloblen > lenleft) { + logeventf(ssh, "Pageant response was truncated"); + s->nkeys = 0; + goto done_agent_query; + } + lenleft -= 4 + bloblen; + q += 4 + bloblen; + commentlen = toint(GET_32BIT(q)); + if (commentlen < 0 || commentlen > lenleft) { + logeventf(ssh, "Pageant response was truncated"); + s->nkeys = 0; + goto done_agent_query; + } + lenleft -= 4 + commentlen; + q += 4 + commentlen; + } + } + p += 4; logeventf(ssh, "Pageant has %d SSH-2 keys", s->nkeys); if (s->publickey_blob) { /* See if configured key is in agent. */ for (keyi = 0; keyi < s->nkeys; keyi++) { - s->pklen = GET_32BIT(p); + s->pklen = toint(GET_32BIT(p)); if (s->pklen == s->publickey_bloblen && !memcmp(p+4, s->publickey_blob, s->publickey_bloblen)) { @@ -7913,7 +7994,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, break; } p += 4 + s->pklen; - p += GET_32BIT(p) + 4; /* comment */ + p += toint(GET_32BIT(p)) + 4; /* comment */ } if (!s->pkblob_in_agent) { logevent("Configured key file not in Pageant"); @@ -7923,6 +8004,7 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, } else { logevent("Failed to get reply from Pageant"); } + done_agent_query:; } } @@ -8174,13 +8256,13 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, logeventf(ssh, "Trying Pageant key #%d", s->keyi); /* Unpack key from agent response */ - s->pklen = GET_32BIT(s->agentp); + s->pklen = toint(GET_32BIT(s->agentp)); s->agentp += 4; s->pkblob = (char *)s->agentp; s->agentp += s->pklen; - s->alglen = GET_32BIT(s->pkblob); + s->alglen = toint(GET_32BIT(s->pkblob)); s->alg = s->pkblob + 4; - s->commentlen = GET_32BIT(s->agentp); + s->commentlen = toint(GET_32BIT(s->agentp)); s->agentp += 4; s->commentp = (char *)s->agentp; s->agentp += s->commentlen; @@ -8284,7 +8366,9 @@ static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, s->ret = vret; sfree(s->agentreq); if (s->ret) { - if (s->ret[4] == SSH2_AGENT_SIGN_RESPONSE) { + if (s->retlen >= 9 && + s->ret[4] == SSH2_AGENT_SIGN_RESPONSE && + GET_32BIT(s->ret + 5) <= (unsigned)(s->retlen-9)) { logevent("Sending Pageant's response"); ssh2_add_sigblob(ssh, s->pktout, s->pkblob, s->pklen,