PuTTy: Diff

Differences From Artifact [739a10a321]:

File ssh.c — part of check-in [86e974bb0e] at 2013-07-07 09:34:37 on branch trunk — Move the SSH-1 servkey and hostkey variables into the coroutine state, since there is a theoretical code path (via the crReturn loop after asking an interactive question about a host key or crypto algorithm) on which we can leave and return to do_ssh1_login between allocating and freeing those keys. (In practice it shouldn't come up anyway with any of the current implementations of the interactive question functions, not to mention the unlikelihood of anyone non-specialist still using SSH-1, but better safe than sorry.) (user: simon size: 310726)

To Artifact [74f3763e1d]:

File ssh.c — part of check-in [845f59bde8] at 2013-07-14 05:45:54 on branch trunk — Tighten up a lot of casts from unsigned to int which are read by one of the GET_32BIT macros and then used as length fields. Missing bounds checks against zero have been added, and also I've introduced a helper function toint() which casts from unsigned to int in such a way as to avoid C undefined behaviour, since I'm not sure I trust compilers any more to do the obviously sensible thing. (user: simon size: 314207)

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1445 1446 1447 1448 1449 1450 1451 ~~1452~~ 1453 1454 1455 1456 1457 1458 1459	1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460	- + +	/* Feed that block to the MAC. / ssh->scmac->bytes(ssh->sc_mac_ctx, st->pktin->data + st->packetlen, st->cipherblk); st->packetlen += st->cipherblk; / 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")); ssh_free_packet(st->pktin); crStop(NULL); } }
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1478 1479 1480 1481 1482 1483 1484 ~~1485~~ 1486 1487 1488 1489 1490 1491 1492	1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493	- +	if (ssh->sccipher) ssh->sccipher->decrypt(ssh->sc_cipher_ctx, st->pktin->data, st->cipherblk); /* * 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 * do us any more damage. */ if (st->len < 0 \|\| st->len > OUR_V2_PACKETLIMIT \|\| (st->len + 4) % st->cipherblk != 0) {
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2309 2310 2311 2312 2313 2314 2315 ~~2316~~ 2317 2318 2319 2320 2321 2322 2323	2310 2311 2312 2313 2314 2315 2316 2317 2318 2319 2320 2321 2322 2323 2324	- +	static void ssh_pkt_getstring(struct Packet pkt, char p, int length) { int len; p = NULL; length = 0; if (pkt->length - pkt->savedpos < 4) return; ~~len = GET_32BIT(pkt->body + pkt->savedpos);~~ len = toint(GET_32BIT(pkt->body + pkt->savedpos)); if (len < 0) return; length = len; pkt->savedpos += 4; if (pkt->length - pkt->savedpos < length) return; p = (char )(pkt->body + pkt->savedpos);
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2393 2394 2395 2396 2397 2398 2399 ~~2400~~ 2401 2402 2403 2404 2405 2406 2407 2408 ~~2409 2410~~ 2411 2412 2413 2414 2415 2416 2417 2418 2419 ~~2420~~ 2421 2422 2423 2424 2425 2426 2427	2394 2395 2396 2397 2398 2399 2400 2401 2402 2403 2404 2405 2406 2407 2408 2409 2410 2411 2412 2413 2414 2415 2416 2417 2418 2419 2420 2421 2422 2423 2424 2425 2426 2427 2428 2429 2430 2431 2432 2433 2434 2435 2436 2437 2438 2439	- + + + + - - + + + + + + + + - + + +	/* dmemdump(pkblob, pkblob_len); / / dmemdump(sigblob, sigblob_len); / / * See if this is in fact an ssh-rsa signature and a buggy * server; otherwise we can just do this the easy way. / ~~if ((ssh->remote_bugs & BUG_SSH2_RSA_PADDING) &&~~ 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; / * Find the byte length of the modulus. / pos = 4+7; / skip over "ssh-rsa" / len = toint(GET_32BIT(pkblob+pos)); / get length of exponent / if (len < 0 \|\| len > pkblob_len - pos - 4) goto give_up; ~~pos += 4 + ~~GET_32BIT(pkb~~l~~ob+pos)~~; / skip over exponent / len = GET_32BIT(pkblob+pos); / find length of modulus /~~ 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++; / debug(("modulus length is %d\n", len)); / / * Now find the signature integer. / pos = 4+7; / skip over "ssh-rsa" / if (sigblob_len < pos+4) goto give_up; ~~siglen = GET_32BIT(sigblob+pos);~~ 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) { unsigned char newlen[4]; ssh2_pkt_addstring_start(pkt); ssh2_pkt_addstring_data(pkt, (char )sigblob, pos); /* dmemdump(sigblob, pos); */
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2435 2436 2437 2438 2439 2440 2441 ~~2442~~ 2443 2444 2445 2446 2447 2448 2449	2447 2448 2449 2450 2451 2452 2453 2454 2455 2456 2457 2458 2459 2460 2461 2462 2463 2464	- + + + +	/* dmemdump(newlen, 1); / } ssh2_pkt_addstring_data(pkt, (char )(sigblob+pos), siglen); /* dmemdump(sigblob+pos, siglen); / return; } ~~/ Otherwise fall through and do it the easy way. /~~ / 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); ssh2_pkt_addstring_data(pkt, (char )sigblob, sigblob_len); } /*
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3673 3674 3675 3676 3677 3678 3679 ~~3680~~ 3681 3682 3683 3684 3685 3686 3687 3688 3689 ~~3690~~ 3691 3692 3693 3694 3695 ~~3696~~ 3697 3698 ~~3699~~ 3700 3701 3702 ~~3703~~ 3704 ~~3705~~ 3706 3707 3708 3709 3710 3711 3712	3688 3689 3690 3691 3692 3693 3694 3695 3696 3697 3698 3699 3700 3701 3702 3703 3704 3705 3706 3707 3708 3709 3710 3711 3712 3713 3714 3715 3716 3717 3718 3719 3720 3721 3722 3723 3724 3725 3726 3727 3728 3729 3730 3731 3732 3733	+ + + + - + + - + - + - + - + + - +	r = ssh->agent_response; s->responselen = ssh->agent_response_len; } s->response = (unsigned char ) r; if (s->response && s->responselen >= 5 && s->response[4] == SSH1_AGENT_RSA_IDENTITIES_ANSWER) { s->p = s->response + 5; s->nkeys = toint(GET_32BIT(s->p)); if (s->nkeys < 0) { logeventf(ssh, "Pageant reported negative key count %d", s->nkeys); ~~s->nkeys = ~~GET_32BIT(s->p)~~;~~ 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++) { unsigned char pkblob = s->p; s->p += 4; { int n, ok = FALSE; do { /* do while (0) to make breaking easy / n = ssh1_read_bignum ~~(s->p, s->responselen-(s->p-s->response),~~ (s->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->commentlen < 0 \|\| ~~if (s->responselen - (s->p-s->response) <~~ toint(s->responselen - (s->p-s->response)) < s->commentlen) break; s->commentp = (char )s->p; s->p += s->commentlen; ok = TRUE; } while (0); if (!ok) {
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7189 7190 7191 7192 7193 7194 7195 ~~7196 7197 7198 7199 7200 7201 7202 7203~~ ~~7204 7205~~ 7206 7207 7208 7209 7210 7211 7212	7210 7211 7212 7213 7214 7215 7216 7217 7218 7219 7220 7221 7222 7223 7224 7225 7226 7227 7228 7229 7230 7231 7232 7233 7234 7235	- - - - - - - - + + + + + + + + + + - - + +	long len = pktin->length - pktin->savedpos; unsigned long num = GET_32BIT(p); /* what is it? / / If it's 0, it hardly matters; assume string */ if (num == 0) { is_int = FALSE; } else { int maybe_int = FALSE, maybe_str = FALSE; #define CHECK_HYPOTHESIS(offset, result) \ ~~do {~~ \ ~~long~~ q = offset; \ if (q >= 0 && q+4 <= len) { \ q = q + 4 + GET_32BIT(p+q); \ if (q >= 0 && q+4 <= len && \ ((q = q + 4 + GET_32BIT(p+q))!= 0) && ~~q == len)~~ \ result = TRUE; \ #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)~~ } \ } while(0) CHECK_HYPOTHESIS(4+1, maybe_int); CHECK_HYPOTHESIS(4+num+1, maybe_str); #undef CHECK_HYPOTHESIS if (maybe_int && !maybe_str) is_int = TRUE; else if (!maybe_int && maybe_str) is_int = FALSE;
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7892 7893 7894 7895 7896 7897 7898 ~~7899~~ 7900 7901 7902 7903 7904 ~~7905~~ 7906 7907 7908 7909 7910 7911 7912 7913 7914 7915 ~~7916~~ 7917 7918 7919 7920 7921 7922 7923 7924 7925 7926 7927 7928 7929 7930 7931 7932	7915 7916 7917 7918 7919 7920 7921 7922 7923 7924 7925 7926 7927 7928 7929 7930 7931 7932 7933 7934 7935 7936 7937 7938 7939 7940 7941 7942 7943 7944 7945 7946 7947 7948 7949 7950 7951 7952 7953 7954 7955 7956 7957 7958 7959 7960 7961 7962 7963 7964 7965 7966 7967 7968 7969 7970 7971 7972 7973 7974 7975 7976 7977 7978 7979 7980 7981 7982 7983 7984 7985 7986 7987 7988 7989 7990 7991 7992 7993 7994 7995 7996	+ + + + + + + + + - + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + - + - + +	} s->agent_response = (unsigned char ) r; if (s->agent_response && s->agent_responselen >= 5 && s->agent_response[4] == SSH2_AGENT_IDENTITIES_ANSWER) { int keyi; unsigned char p; p = s->agent_response + 5; 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 = ~~GET_32BIT(p)~~;~~ 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)) { logeventf(ssh, "Pageant key #%d matches " "configured key file", keyi); s->keyi = keyi; s->pkblob_in_agent = p; 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"); s->nkeys = 0; } } } else { logevent("Failed to get reply from Pageant"); } done_agent_query:; } } / * We repeat this whole loop, including the username prompt, * until we manage a successful authentication. If the user
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8170 8171 8172 8173 8174 8175 8176 ~~8177~~ 8178 8179 8180 ~~8181~~ 8182 ~~8183~~ 8184 8185 8186 8187 8188 8189 8190	8234 8235 8236 8237 8238 8239 8240 8241 8242 8243 8244 8245 8246 8247 8248 8249 8250 8251 8252 8253 8254	- + - + - +	/ ssh->pkt_actx = SSH2_PKTCTX_PUBLICKEY; 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; / s->agentp now points at next key, if any / / See if server will accept it */ s->pktout = ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
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8280 8281 8282 8283 8284 8285 8286 ~~8287~~ 8288 8289 8290 8291 8292 8293 8294	8344 8345 8346 8347 8348 8349 8350 8351 8352 8353 8354 8355 8356 8357 8358 8359 8360	+ - + +	} while (pktin \|\| inlen > 0); vret = ssh->agent_response; s->retlen = ssh->agent_response_len; } s->ret = vret; sfree(s->agentreq); if (s->ret) { if (s->retlen >= 9 && ~~if (s->ret[4] == SSH2_AGENT_SIGN_RESPONSE~~) {~~~~ 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, s->ret + 9, GET_32BIT(s->ret + 5)); ssh2_pkt_send(ssh, s->pktout); s->type = AUTH_TYPE_PUBLICKEY;
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