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a306f2dd | 1 | /* |
2 | * Copyright (c) 2000 Markus Friedl. All rights reserved. | |
3 | * | |
4 | * Redistribution and use in source and binary forms, with or without | |
5 | * modification, are permitted provided that the following conditions | |
6 | * are met: | |
7 | * 1. Redistributions of source code must retain the above copyright | |
8 | * notice, this list of conditions and the following disclaimer. | |
9 | * 2. Redistributions in binary form must reproduce the above copyright | |
10 | * notice, this list of conditions and the following disclaimer in the | |
11 | * documentation and/or other materials provided with the distribution. | |
a306f2dd | 12 | * |
13 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR | |
14 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES | |
15 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. | |
16 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, | |
17 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
18 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
19 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
20 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
21 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | |
22 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
23 | */ | |
24 | ||
25 | #include "includes.h" | |
1ad64a93 | 26 | RCSID("$OpenBSD: sshconnect2.c,v 1.60 2001/03/29 21:06:21 stevesk Exp $"); |
a306f2dd | 27 | |
28 | #include <openssl/bn.h> | |
a306f2dd | 29 | #include <openssl/md5.h> |
30 | #include <openssl/dh.h> | |
31 | #include <openssl/hmac.h> | |
32 | ||
33 | #include "ssh.h" | |
42f11eb2 | 34 | #include "ssh2.h" |
a306f2dd | 35 | #include "xmalloc.h" |
36 | #include "rsa.h" | |
37 | #include "buffer.h" | |
38 | #include "packet.h" | |
a306f2dd | 39 | #include "uidswap.h" |
40 | #include "compat.h" | |
a306f2dd | 41 | #include "bufaux.h" |
42f11eb2 | 42 | #include "cipher.h" |
a306f2dd | 43 | #include "kex.h" |
44 | #include "myproposal.h" | |
45 | #include "key.h" | |
a306f2dd | 46 | #include "sshconnect.h" |
47 | #include "authfile.h" | |
94ec8c6b | 48 | #include "cli.h" |
db1cd2f3 | 49 | #include "dh.h" |
188adeb2 | 50 | #include "dispatch.h" |
2e73a022 | 51 | #include "authfd.h" |
42f11eb2 | 52 | #include "log.h" |
53 | #include "readconf.h" | |
54 | #include "readpass.h" | |
cab80f75 | 55 | #include "match.h" |
a306f2dd | 56 | |
94ec8c6b | 57 | void ssh_dh1_client(Kex *, char *, struct sockaddr *, Buffer *, Buffer *); |
58 | void ssh_dhgex_client(Kex *, char *, struct sockaddr *, Buffer *, Buffer *); | |
59 | ||
a306f2dd | 60 | /* import */ |
61 | extern char *client_version_string; | |
62 | extern char *server_version_string; | |
63 | extern Options options; | |
64 | ||
65 | /* | |
66 | * SSH2 key exchange | |
67 | */ | |
68 | ||
1e3b8b07 | 69 | u_char *session_id2 = NULL; |
a306f2dd | 70 | int session_id2_len = 0; |
71 | ||
72 | void | |
94ec8c6b | 73 | ssh_kex2(char *host, struct sockaddr *hostaddr) |
74 | { | |
75 | int i, plen; | |
76 | Kex *kex; | |
77 | Buffer *client_kexinit, *server_kexinit; | |
78 | char *sprop[PROPOSAL_MAX]; | |
79 | ||
c523303b | 80 | if (options.ciphers == (char *)-1) { |
81 | log("No valid ciphers for protocol version 2 given, using defaults."); | |
82 | options.ciphers = NULL; | |
94ec8c6b | 83 | } |
84 | if (options.ciphers != NULL) { | |
85 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = | |
86 | myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; | |
87 | } | |
1ad64a93 | 88 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = |
89 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); | |
90 | myproposal[PROPOSAL_ENC_ALGS_STOC] = | |
91 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); | |
94ec8c6b | 92 | if (options.compression) { |
b2552997 | 93 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = |
94ec8c6b | 94 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib"; |
95 | } else { | |
b2552997 | 96 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = |
94ec8c6b | 97 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none"; |
98 | } | |
b2552997 | 99 | if (options.macs != NULL) { |
100 | myproposal[PROPOSAL_MAC_ALGS_CTOS] = | |
101 | myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; | |
102 | } | |
94ec8c6b | 103 | |
104 | /* buffers with raw kexinit messages */ | |
105 | server_kexinit = xmalloc(sizeof(*server_kexinit)); | |
106 | buffer_init(server_kexinit); | |
107 | client_kexinit = kex_init(myproposal); | |
108 | ||
109 | /* algorithm negotiation */ | |
110 | kex_exchange_kexinit(client_kexinit, server_kexinit, sprop); | |
111 | kex = kex_choose_conf(myproposal, sprop, 0); | |
112 | for (i = 0; i < PROPOSAL_MAX; i++) | |
113 | xfree(sprop[i]); | |
114 | ||
115 | /* server authentication and session key agreement */ | |
116 | switch(kex->kex_type) { | |
117 | case DH_GRP1_SHA1: | |
118 | ssh_dh1_client(kex, host, hostaddr, | |
119 | client_kexinit, server_kexinit); | |
120 | break; | |
121 | case DH_GEX_SHA1: | |
122 | ssh_dhgex_client(kex, host, hostaddr, client_kexinit, | |
123 | server_kexinit); | |
124 | break; | |
125 | default: | |
126 | fatal("Unsupported key exchange %d", kex->kex_type); | |
127 | } | |
128 | ||
129 | buffer_free(client_kexinit); | |
130 | buffer_free(server_kexinit); | |
131 | xfree(client_kexinit); | |
132 | xfree(server_kexinit); | |
133 | ||
134 | debug("Wait SSH2_MSG_NEWKEYS."); | |
135 | packet_read_expect(&plen, SSH2_MSG_NEWKEYS); | |
136 | packet_done(); | |
137 | debug("GOT SSH2_MSG_NEWKEYS."); | |
138 | ||
139 | debug("send SSH2_MSG_NEWKEYS."); | |
140 | packet_start(SSH2_MSG_NEWKEYS); | |
141 | packet_send(); | |
142 | packet_write_wait(); | |
143 | debug("done: send SSH2_MSG_NEWKEYS."); | |
144 | ||
145 | #ifdef DEBUG_KEXDH | |
146 | /* send 1st encrypted/maced/compressed message */ | |
147 | packet_start(SSH2_MSG_IGNORE); | |
148 | packet_put_cstring("markus"); | |
149 | packet_send(); | |
150 | packet_write_wait(); | |
151 | #endif | |
152 | debug("done: KEX2."); | |
153 | } | |
154 | ||
155 | /* diffie-hellman-group1-sha1 */ | |
156 | ||
157 | void | |
2b87da3b | 158 | ssh_dh1_client(Kex *kex, char *host, struct sockaddr *hostaddr, |
94ec8c6b | 159 | Buffer *client_kexinit, Buffer *server_kexinit) |
a306f2dd | 160 | { |
188adeb2 | 161 | #ifdef DEBUG_KEXDH |
162 | int i; | |
163 | #endif | |
71276795 | 164 | int plen, dlen; |
1e3b8b07 | 165 | u_int klen, kout; |
a306f2dd | 166 | char *signature = NULL; |
1e3b8b07 | 167 | u_int slen; |
a306f2dd | 168 | char *server_host_key_blob = NULL; |
169 | Key *server_host_key; | |
1e3b8b07 | 170 | u_int sbloblen; |
a306f2dd | 171 | DH *dh; |
172 | BIGNUM *dh_server_pub = 0; | |
173 | BIGNUM *shared_secret = 0; | |
1e3b8b07 | 174 | u_char *kbuf; |
175 | u_char *hash; | |
a306f2dd | 176 | |
a306f2dd | 177 | debug("Sending SSH2_MSG_KEXDH_INIT."); |
a306f2dd | 178 | /* generate and send 'e', client DH public key */ |
179 | dh = dh_new_group1(); | |
7de5b06b | 180 | dh_gen_key(dh, kex->we_need * 8); |
a306f2dd | 181 | packet_start(SSH2_MSG_KEXDH_INIT); |
182 | packet_put_bignum2(dh->pub_key); | |
183 | packet_send(); | |
184 | packet_write_wait(); | |
185 | ||
186 | #ifdef DEBUG_KEXDH | |
187 | fprintf(stderr, "\np= "); | |
188adeb2 | 188 | BN_print_fp(stderr, dh->p); |
a306f2dd | 189 | fprintf(stderr, "\ng= "); |
188adeb2 | 190 | BN_print_fp(stderr, dh->g); |
a306f2dd | 191 | fprintf(stderr, "\npub= "); |
188adeb2 | 192 | BN_print_fp(stderr, dh->pub_key); |
a306f2dd | 193 | fprintf(stderr, "\n"); |
194 | DHparams_print_fp(stderr, dh); | |
195 | #endif | |
196 | ||
197 | debug("Wait SSH2_MSG_KEXDH_REPLY."); | |
198 | ||
71276795 | 199 | packet_read_expect(&plen, SSH2_MSG_KEXDH_REPLY); |
a306f2dd | 200 | |
201 | debug("Got SSH2_MSG_KEXDH_REPLY."); | |
202 | ||
203 | /* key, cert */ | |
204 | server_host_key_blob = packet_get_string(&sbloblen); | |
fa08c86b | 205 | server_host_key = key_from_blob(server_host_key_blob, sbloblen); |
a306f2dd | 206 | if (server_host_key == NULL) |
207 | fatal("cannot decode server_host_key_blob"); | |
208 | ||
209 | check_host_key(host, hostaddr, server_host_key, | |
94ec8c6b | 210 | options.user_hostfile2, options.system_hostfile2); |
a306f2dd | 211 | |
212 | /* DH paramter f, server public DH key */ | |
213 | dh_server_pub = BN_new(); | |
214 | if (dh_server_pub == NULL) | |
215 | fatal("dh_server_pub == NULL"); | |
216 | packet_get_bignum2(dh_server_pub, &dlen); | |
217 | ||
218 | #ifdef DEBUG_KEXDH | |
219 | fprintf(stderr, "\ndh_server_pub= "); | |
188adeb2 | 220 | BN_print_fp(stderr, dh_server_pub); |
a306f2dd | 221 | fprintf(stderr, "\n"); |
222 | debug("bits %d", BN_num_bits(dh_server_pub)); | |
223 | #endif | |
224 | ||
225 | /* signed H */ | |
226 | signature = packet_get_string(&slen); | |
227 | packet_done(); | |
228 | ||
229 | if (!dh_pub_is_valid(dh, dh_server_pub)) | |
230 | packet_disconnect("bad server public DH value"); | |
231 | ||
232 | klen = DH_size(dh); | |
233 | kbuf = xmalloc(klen); | |
234 | kout = DH_compute_key(kbuf, dh_server_pub, dh); | |
235 | #ifdef DEBUG_KEXDH | |
236 | debug("shared secret: len %d/%d", klen, kout); | |
237 | fprintf(stderr, "shared secret == "); | |
238 | for (i = 0; i< kout; i++) | |
239 | fprintf(stderr, "%02x", (kbuf[i])&0xff); | |
240 | fprintf(stderr, "\n"); | |
241 | #endif | |
242 | shared_secret = BN_new(); | |
243 | ||
244 | BN_bin2bn(kbuf, kout, shared_secret); | |
245 | memset(kbuf, 0, klen); | |
246 | xfree(kbuf); | |
247 | ||
248 | /* calc and verify H */ | |
249 | hash = kex_hash( | |
250 | client_version_string, | |
251 | server_version_string, | |
252 | buffer_ptr(client_kexinit), buffer_len(client_kexinit), | |
253 | buffer_ptr(server_kexinit), buffer_len(server_kexinit), | |
254 | server_host_key_blob, sbloblen, | |
255 | dh->pub_key, | |
256 | dh_server_pub, | |
257 | shared_secret | |
258 | ); | |
259 | xfree(server_host_key_blob); | |
71276795 | 260 | DH_free(dh); |
53a24016 | 261 | BN_free(dh_server_pub); |
a306f2dd | 262 | #ifdef DEBUG_KEXDH |
263 | fprintf(stderr, "hash == "); | |
264 | for (i = 0; i< 20; i++) | |
265 | fprintf(stderr, "%02x", (hash[i])&0xff); | |
266 | fprintf(stderr, "\n"); | |
267 | #endif | |
1e3b8b07 | 268 | if (key_verify(server_host_key, (u_char *)signature, slen, hash, 20) != 1) |
fa08c86b | 269 | fatal("key_verify failed for server_host_key"); |
a306f2dd | 270 | key_free(server_host_key); |
53a24016 | 271 | xfree(signature); |
a306f2dd | 272 | |
273 | kex_derive_keys(kex, hash, shared_secret); | |
53a24016 | 274 | BN_clear_free(shared_secret); |
a306f2dd | 275 | packet_set_kex(kex); |
276 | ||
a306f2dd | 277 | /* save session id */ |
278 | session_id2_len = 20; | |
279 | session_id2 = xmalloc(session_id2_len); | |
280 | memcpy(session_id2, hash, session_id2_len); | |
71276795 | 281 | } |
282 | ||
94ec8c6b | 283 | /* diffie-hellman-group-exchange-sha1 */ |
284 | ||
285 | /* | |
286 | * Estimates the group order for a Diffie-Hellman group that has an | |
287 | * attack complexity approximately the same as O(2**bits). Estimate | |
288 | * with: O(exp(1.9223 * (ln q)^(1/3) (ln ln q)^(2/3))) | |
289 | */ | |
290 | ||
291 | int | |
292 | dh_estimate(int bits) | |
293 | { | |
2b87da3b | 294 | |
94ec8c6b | 295 | if (bits < 64) |
296 | return (512); /* O(2**63) */ | |
297 | if (bits < 128) | |
298 | return (1024); /* O(2**86) */ | |
299 | if (bits < 192) | |
300 | return (2048); /* O(2**116) */ | |
301 | return (4096); /* O(2**156) */ | |
302 | } | |
303 | ||
71276795 | 304 | void |
94ec8c6b | 305 | ssh_dhgex_client(Kex *kex, char *host, struct sockaddr *hostaddr, |
306 | Buffer *client_kexinit, Buffer *server_kexinit) | |
71276795 | 307 | { |
94ec8c6b | 308 | #ifdef DEBUG_KEXDH |
309 | int i; | |
310 | #endif | |
311 | int plen, dlen; | |
1e3b8b07 | 312 | u_int klen, kout; |
94ec8c6b | 313 | char *signature = NULL; |
db1cd2f3 | 314 | u_int slen, nbits, min, max; |
94ec8c6b | 315 | char *server_host_key_blob = NULL; |
316 | Key *server_host_key; | |
1e3b8b07 | 317 | u_int sbloblen; |
94ec8c6b | 318 | DH *dh; |
319 | BIGNUM *dh_server_pub = 0; | |
320 | BIGNUM *shared_secret = 0; | |
321 | BIGNUM *p = 0, *g = 0; | |
1e3b8b07 | 322 | u_char *kbuf; |
323 | u_char *hash; | |
71276795 | 324 | |
7de5b06b | 325 | nbits = dh_estimate(kex->we_need * 8); |
71276795 | 326 | |
db1cd2f3 | 327 | if (datafellows & SSH_OLD_DHGEX) { |
328 | debug("Sending SSH2_MSG_KEX_DH_GEX_REQUEST_OLD."); | |
329 | ||
330 | /* Old GEX request */ | |
331 | packet_start(SSH2_MSG_KEX_DH_GEX_REQUEST_OLD); | |
332 | packet_put_int(nbits); | |
333 | min = DH_GRP_MIN; | |
334 | max = DH_GRP_MAX; | |
335 | } else { | |
336 | debug("Sending SSH2_MSG_KEX_DH_GEX_REQUEST."); | |
337 | ||
338 | /* New GEX request */ | |
339 | min = DH_GRP_MIN; | |
86b878d5 | 340 | max = DH_GRP_MAX; |
db1cd2f3 | 341 | |
342 | packet_start(SSH2_MSG_KEX_DH_GEX_REQUEST); | |
343 | packet_put_int(min); | |
344 | packet_put_int(nbits); | |
345 | packet_put_int(max); | |
346 | } | |
94ec8c6b | 347 | packet_send(); |
348 | packet_write_wait(); | |
71276795 | 349 | |
94ec8c6b | 350 | #ifdef DEBUG_KEXDH |
db1cd2f3 | 351 | fprintf(stderr, "\nmin = %d, nbits = %d, max = %d", min, nbits, max); |
94ec8c6b | 352 | #endif |
71276795 | 353 | |
94ec8c6b | 354 | debug("Wait SSH2_MSG_KEX_DH_GEX_GROUP."); |
71276795 | 355 | |
94ec8c6b | 356 | packet_read_expect(&plen, SSH2_MSG_KEX_DH_GEX_GROUP); |
a306f2dd | 357 | |
94ec8c6b | 358 | debug("Got SSH2_MSG_KEX_DH_GEX_GROUP."); |
a306f2dd | 359 | |
94ec8c6b | 360 | if ((p = BN_new()) == NULL) |
361 | fatal("BN_new"); | |
362 | packet_get_bignum2(p, &dlen); | |
363 | if ((g = BN_new()) == NULL) | |
364 | fatal("BN_new"); | |
365 | packet_get_bignum2(g, &dlen); | |
db1cd2f3 | 366 | |
367 | if (BN_num_bits(p) < min || BN_num_bits(p) > max) | |
368 | fatal("DH_GEX group out of range: %d !< %d !< %d", | |
369 | min, BN_num_bits(p), max); | |
370 | ||
42f11eb2 | 371 | dh = dh_new_group(g, p); |
a306f2dd | 372 | |
7de5b06b | 373 | dh_gen_key(dh, kex->we_need * 8); |
3e1caa83 | 374 | |
a306f2dd | 375 | #ifdef DEBUG_KEXDH |
94ec8c6b | 376 | fprintf(stderr, "\np= "); |
377 | BN_print_fp(stderr, dh->p); | |
378 | fprintf(stderr, "\ng= "); | |
379 | BN_print_fp(stderr, dh->g); | |
380 | fprintf(stderr, "\npub= "); | |
381 | BN_print_fp(stderr, dh->pub_key); | |
382 | fprintf(stderr, "\n"); | |
383 | DHparams_print_fp(stderr, dh); | |
384 | #endif | |
385 | ||
386 | debug("Sending SSH2_MSG_KEX_DH_GEX_INIT."); | |
387 | /* generate and send 'e', client DH public key */ | |
388 | packet_start(SSH2_MSG_KEX_DH_GEX_INIT); | |
389 | packet_put_bignum2(dh->pub_key); | |
a306f2dd | 390 | packet_send(); |
391 | packet_write_wait(); | |
94ec8c6b | 392 | |
393 | debug("Wait SSH2_MSG_KEX_DH_GEX_REPLY."); | |
394 | ||
395 | packet_read_expect(&plen, SSH2_MSG_KEX_DH_GEX_REPLY); | |
396 | ||
397 | debug("Got SSH2_MSG_KEXDH_REPLY."); | |
398 | ||
399 | /* key, cert */ | |
400 | server_host_key_blob = packet_get_string(&sbloblen); | |
fa08c86b | 401 | server_host_key = key_from_blob(server_host_key_blob, sbloblen); |
94ec8c6b | 402 | if (server_host_key == NULL) |
403 | fatal("cannot decode server_host_key_blob"); | |
404 | ||
405 | check_host_key(host, hostaddr, server_host_key, | |
406 | options.user_hostfile2, options.system_hostfile2); | |
407 | ||
408 | /* DH paramter f, server public DH key */ | |
409 | dh_server_pub = BN_new(); | |
410 | if (dh_server_pub == NULL) | |
411 | fatal("dh_server_pub == NULL"); | |
412 | packet_get_bignum2(dh_server_pub, &dlen); | |
413 | ||
414 | #ifdef DEBUG_KEXDH | |
415 | fprintf(stderr, "\ndh_server_pub= "); | |
416 | BN_print_fp(stderr, dh_server_pub); | |
417 | fprintf(stderr, "\n"); | |
418 | debug("bits %d", BN_num_bits(dh_server_pub)); | |
a306f2dd | 419 | #endif |
94ec8c6b | 420 | |
421 | /* signed H */ | |
422 | signature = packet_get_string(&slen); | |
423 | packet_done(); | |
424 | ||
425 | if (!dh_pub_is_valid(dh, dh_server_pub)) | |
426 | packet_disconnect("bad server public DH value"); | |
427 | ||
428 | klen = DH_size(dh); | |
429 | kbuf = xmalloc(klen); | |
430 | kout = DH_compute_key(kbuf, dh_server_pub, dh); | |
431 | #ifdef DEBUG_KEXDH | |
432 | debug("shared secret: len %d/%d", klen, kout); | |
433 | fprintf(stderr, "shared secret == "); | |
434 | for (i = 0; i< kout; i++) | |
435 | fprintf(stderr, "%02x", (kbuf[i])&0xff); | |
436 | fprintf(stderr, "\n"); | |
437 | #endif | |
438 | shared_secret = BN_new(); | |
439 | ||
440 | BN_bin2bn(kbuf, kout, shared_secret); | |
441 | memset(kbuf, 0, klen); | |
442 | xfree(kbuf); | |
443 | ||
4047d868 | 444 | if (datafellows & SSH_OLD_DHGEX) { |
445 | /* These values are not included in the hash */ | |
446 | min = -1; | |
447 | max = -1; | |
448 | } | |
449 | ||
94ec8c6b | 450 | /* calc and verify H */ |
451 | hash = kex_hash_gex( | |
452 | client_version_string, | |
453 | server_version_string, | |
454 | buffer_ptr(client_kexinit), buffer_len(client_kexinit), | |
455 | buffer_ptr(server_kexinit), buffer_len(server_kexinit), | |
456 | server_host_key_blob, sbloblen, | |
4047d868 | 457 | min, nbits, max, |
458 | dh->p, dh->g, | |
94ec8c6b | 459 | dh->pub_key, |
460 | dh_server_pub, | |
461 | shared_secret | |
462 | ); | |
463 | xfree(server_host_key_blob); | |
464 | DH_free(dh); | |
53a24016 | 465 | BN_free(dh_server_pub); |
94ec8c6b | 466 | #ifdef DEBUG_KEXDH |
467 | fprintf(stderr, "hash == "); | |
468 | for (i = 0; i< 20; i++) | |
469 | fprintf(stderr, "%02x", (hash[i])&0xff); | |
470 | fprintf(stderr, "\n"); | |
471 | #endif | |
1e3b8b07 | 472 | if (key_verify(server_host_key, (u_char *)signature, slen, hash, 20) != 1) |
fa08c86b | 473 | fatal("key_verify failed for server_host_key"); |
94ec8c6b | 474 | key_free(server_host_key); |
53a24016 | 475 | xfree(signature); |
94ec8c6b | 476 | |
477 | kex_derive_keys(kex, hash, shared_secret); | |
53a24016 | 478 | BN_clear_free(shared_secret); |
94ec8c6b | 479 | packet_set_kex(kex); |
480 | ||
481 | /* save session id */ | |
482 | session_id2_len = 20; | |
483 | session_id2 = xmalloc(session_id2_len); | |
484 | memcpy(session_id2, hash, session_id2_len); | |
a306f2dd | 485 | } |
71276795 | 486 | |
a306f2dd | 487 | /* |
488 | * Authenticate user | |
489 | */ | |
188adeb2 | 490 | |
491 | typedef struct Authctxt Authctxt; | |
492 | typedef struct Authmethod Authmethod; | |
493 | ||
494 | typedef int sign_cb_fn( | |
495 | Authctxt *authctxt, Key *key, | |
1e3b8b07 | 496 | u_char **sigp, int *lenp, u_char *data, int datalen); |
188adeb2 | 497 | |
498 | struct Authctxt { | |
499 | const char *server_user; | |
500 | const char *host; | |
501 | const char *service; | |
502 | AuthenticationConnection *agent; | |
188adeb2 | 503 | Authmethod *method; |
94ec8c6b | 504 | int success; |
fee56204 | 505 | char *authlist; |
506 | Key *last_key; | |
507 | sign_cb_fn *last_key_sign; | |
508 | int last_key_hint; | |
188adeb2 | 509 | }; |
510 | struct Authmethod { | |
511 | char *name; /* string to compare against server's list */ | |
512 | int (*userauth)(Authctxt *authctxt); | |
513 | int *enabled; /* flag in option struct that enables method */ | |
514 | int *batch_flag; /* flag in option struct that disables method */ | |
515 | }; | |
516 | ||
517 | void input_userauth_success(int type, int plen, void *ctxt); | |
518 | void input_userauth_failure(int type, int plen, void *ctxt); | |
9616313f | 519 | void input_userauth_banner(int type, int plen, void *ctxt); |
188adeb2 | 520 | void input_userauth_error(int type, int plen, void *ctxt); |
94ec8c6b | 521 | void input_userauth_info_req(int type, int plen, void *ctxt); |
fee56204 | 522 | void input_userauth_pk_ok(int type, int plen, void *ctxt); |
94ec8c6b | 523 | |
524 | int userauth_none(Authctxt *authctxt); | |
188adeb2 | 525 | int userauth_pubkey(Authctxt *authctxt); |
526 | int userauth_passwd(Authctxt *authctxt); | |
94ec8c6b | 527 | int userauth_kbdint(Authctxt *authctxt); |
188adeb2 | 528 | |
fee56204 | 529 | void userauth(Authctxt *authctxt, char *authlist); |
530 | ||
531 | int | |
532 | sign_and_send_pubkey(Authctxt *authctxt, Key *k, | |
533 | sign_cb_fn *sign_callback); | |
534 | void clear_auth_state(Authctxt *authctxt); | |
535 | ||
94ec8c6b | 536 | Authmethod *authmethod_get(char *authlist); |
537 | Authmethod *authmethod_lookup(const char *name); | |
cab80f75 | 538 | char *authmethods_get(void); |
188adeb2 | 539 | |
540 | Authmethod authmethods[] = { | |
541 | {"publickey", | |
542 | userauth_pubkey, | |
fa08c86b | 543 | &options.pubkey_authentication, |
188adeb2 | 544 | NULL}, |
545 | {"password", | |
546 | userauth_passwd, | |
547 | &options.password_authentication, | |
548 | &options.batch_mode}, | |
94ec8c6b | 549 | {"keyboard-interactive", |
550 | userauth_kbdint, | |
551 | &options.kbd_interactive_authentication, | |
552 | &options.batch_mode}, | |
553 | {"none", | |
554 | userauth_none, | |
555 | NULL, | |
556 | NULL}, | |
188adeb2 | 557 | {NULL, NULL, NULL, NULL} |
558 | }; | |
559 | ||
560 | void | |
561 | ssh_userauth2(const char *server_user, char *host) | |
562 | { | |
563 | Authctxt authctxt; | |
564 | int type; | |
565 | int plen; | |
566 | ||
d464095c | 567 | if (options.challenge_reponse_authentication) |
568 | options.kbd_interactive_authentication = 1; | |
569 | ||
188adeb2 | 570 | debug("send SSH2_MSG_SERVICE_REQUEST"); |
571 | packet_start(SSH2_MSG_SERVICE_REQUEST); | |
572 | packet_put_cstring("ssh-userauth"); | |
573 | packet_send(); | |
574 | packet_write_wait(); | |
575 | type = packet_read(&plen); | |
576 | if (type != SSH2_MSG_SERVICE_ACCEPT) { | |
577 | fatal("denied SSH2_MSG_SERVICE_ACCEPT: %d", type); | |
578 | } | |
579 | if (packet_remaining() > 0) { | |
580 | char *reply = packet_get_string(&plen); | |
581 | debug("service_accept: %s", reply); | |
582 | xfree(reply); | |
188adeb2 | 583 | } else { |
584 | debug("buggy server: service_accept w/o service"); | |
585 | } | |
586 | packet_done(); | |
587 | debug("got SSH2_MSG_SERVICE_ACCEPT"); | |
588 | ||
cab80f75 | 589 | if (options.preferred_authentications == NULL) |
590 | options.preferred_authentications = authmethods_get(); | |
591 | ||
188adeb2 | 592 | /* setup authentication context */ |
593 | authctxt.agent = ssh_get_authentication_connection(); | |
594 | authctxt.server_user = server_user; | |
595 | authctxt.host = host; | |
596 | authctxt.service = "ssh-connection"; /* service name */ | |
597 | authctxt.success = 0; | |
94ec8c6b | 598 | authctxt.method = authmethod_lookup("none"); |
fee56204 | 599 | authctxt.authlist = NULL; |
94ec8c6b | 600 | if (authctxt.method == NULL) |
601 | fatal("ssh_userauth2: internal error: cannot send userauth none request"); | |
188adeb2 | 602 | |
603 | /* initial userauth request */ | |
94ec8c6b | 604 | userauth_none(&authctxt); |
188adeb2 | 605 | |
606 | dispatch_init(&input_userauth_error); | |
607 | dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); | |
608 | dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure); | |
9616313f | 609 | dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner); |
188adeb2 | 610 | dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */ |
611 | ||
612 | if (authctxt.agent != NULL) | |
613 | ssh_close_authentication_connection(authctxt.agent); | |
614 | ||
8abcdba4 | 615 | debug("ssh-userauth2 successful: method %s", authctxt.method->name); |
188adeb2 | 616 | } |
617 | void | |
fee56204 | 618 | userauth(Authctxt *authctxt, char *authlist) |
619 | { | |
620 | if (authlist == NULL) { | |
621 | authlist = authctxt->authlist; | |
622 | } else { | |
623 | if (authctxt->authlist) | |
624 | xfree(authctxt->authlist); | |
625 | authctxt->authlist = authlist; | |
626 | } | |
627 | for (;;) { | |
628 | Authmethod *method = authmethod_get(authlist); | |
629 | if (method == NULL) | |
630 | fatal("Permission denied (%s).", authlist); | |
631 | authctxt->method = method; | |
632 | if (method->userauth(authctxt) != 0) { | |
633 | debug2("we sent a %s packet, wait for reply", method->name); | |
634 | break; | |
635 | } else { | |
636 | debug2("we did not send a packet, disable method"); | |
637 | method->enabled = NULL; | |
638 | } | |
639 | } | |
640 | } | |
641 | void | |
188adeb2 | 642 | input_userauth_error(int type, int plen, void *ctxt) |
643 | { | |
9616313f | 644 | fatal("input_userauth_error: bad message during authentication: " |
645 | "type %d", type); | |
646 | } | |
647 | void | |
648 | input_userauth_banner(int type, int plen, void *ctxt) | |
649 | { | |
650 | char *msg, *lang; | |
651 | debug3("input_userauth_banner"); | |
652 | msg = packet_get_string(NULL); | |
653 | lang = packet_get_string(NULL); | |
654 | fprintf(stderr, "%s", msg); | |
655 | xfree(msg); | |
656 | xfree(lang); | |
188adeb2 | 657 | } |
658 | void | |
659 | input_userauth_success(int type, int plen, void *ctxt) | |
660 | { | |
661 | Authctxt *authctxt = ctxt; | |
662 | if (authctxt == NULL) | |
663 | fatal("input_userauth_success: no authentication context"); | |
fee56204 | 664 | if (authctxt->authlist) |
665 | xfree(authctxt->authlist); | |
666 | clear_auth_state(authctxt); | |
188adeb2 | 667 | authctxt->success = 1; /* break out */ |
668 | } | |
669 | void | |
670 | input_userauth_failure(int type, int plen, void *ctxt) | |
671 | { | |
188adeb2 | 672 | Authctxt *authctxt = ctxt; |
673 | char *authlist = NULL; | |
674 | int partial; | |
188adeb2 | 675 | |
676 | if (authctxt == NULL) | |
677 | fatal("input_userauth_failure: no authentication context"); | |
678 | ||
94ec8c6b | 679 | authlist = packet_get_string(NULL); |
188adeb2 | 680 | partial = packet_get_char(); |
681 | packet_done(); | |
682 | ||
683 | if (partial != 0) | |
f72e01a5 | 684 | log("Authenticated with partial success."); |
188adeb2 | 685 | debug("authentications that can continue: %s", authlist); |
686 | ||
fee56204 | 687 | clear_auth_state(authctxt); |
688 | userauth(authctxt, authlist); | |
689 | } | |
690 | void | |
691 | input_userauth_pk_ok(int type, int plen, void *ctxt) | |
692 | { | |
693 | Authctxt *authctxt = ctxt; | |
694 | Key *key = NULL; | |
695 | Buffer b; | |
696 | int alen, blen, pktype, sent = 0; | |
22138a36 | 697 | char *pkalg, *pkblob, *fp; |
fee56204 | 698 | |
699 | if (authctxt == NULL) | |
700 | fatal("input_userauth_pk_ok: no authentication context"); | |
701 | if (datafellows & SSH_BUG_PKOK) { | |
702 | /* this is similar to SSH_BUG_PKAUTH */ | |
703 | debug2("input_userauth_pk_ok: SSH_BUG_PKOK"); | |
704 | pkblob = packet_get_string(&blen); | |
705 | buffer_init(&b); | |
706 | buffer_append(&b, pkblob, blen); | |
707 | pkalg = buffer_get_string(&b, &alen); | |
708 | buffer_free(&b); | |
709 | } else { | |
710 | pkalg = packet_get_string(&alen); | |
711 | pkblob = packet_get_string(&blen); | |
712 | } | |
713 | packet_done(); | |
714 | ||
715 | debug("input_userauth_pk_ok: pkalg %s blen %d lastkey %p hint %d", | |
716 | pkalg, blen, authctxt->last_key, authctxt->last_key_hint); | |
717 | ||
718 | do { | |
719 | if (authctxt->last_key == NULL || | |
720 | authctxt->last_key_sign == NULL) { | |
721 | debug("no last key or no sign cb"); | |
188adeb2 | 722 | break; |
188adeb2 | 723 | } |
fee56204 | 724 | if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) { |
725 | debug("unknown pkalg %s", pkalg); | |
726 | break; | |
727 | } | |
728 | if ((key = key_from_blob(pkblob, blen)) == NULL) { | |
729 | debug("no key from blob. pkalg %s", pkalg); | |
730 | break; | |
731 | } | |
22138a36 | 732 | fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX); |
733 | debug2("input_userauth_pk_ok: fp %s", fp); | |
734 | xfree(fp); | |
fee56204 | 735 | if (!key_equal(key, authctxt->last_key)) { |
736 | debug("key != last_key"); | |
737 | break; | |
738 | } | |
739 | sent = sign_and_send_pubkey(authctxt, key, | |
740 | authctxt->last_key_sign); | |
741 | } while(0); | |
742 | ||
743 | if (key != NULL) | |
744 | key_free(key); | |
745 | xfree(pkalg); | |
746 | xfree(pkblob); | |
747 | ||
748 | /* unregister */ | |
749 | clear_auth_state(authctxt); | |
750 | dispatch_set(SSH2_MSG_USERAUTH_PK_OK, NULL); | |
751 | ||
752 | /* try another method if we did not send a packet*/ | |
753 | if (sent == 0) | |
754 | userauth(authctxt, NULL); | |
755 | ||
188adeb2 | 756 | } |
757 | ||
94ec8c6b | 758 | int |
759 | userauth_none(Authctxt *authctxt) | |
760 | { | |
761 | /* initial userauth request */ | |
762 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
763 | packet_put_cstring(authctxt->server_user); | |
764 | packet_put_cstring(authctxt->service); | |
765 | packet_put_cstring(authctxt->method->name); | |
766 | packet_send(); | |
94ec8c6b | 767 | return 1; |
768 | } | |
769 | ||
a306f2dd | 770 | int |
188adeb2 | 771 | userauth_passwd(Authctxt *authctxt) |
a306f2dd | 772 | { |
1d1ffb87 | 773 | static int attempt = 0; |
a306f2dd | 774 | char prompt[80]; |
775 | char *password; | |
776 | ||
fa649821 | 777 | if (attempt++ >= options.number_of_password_prompts) |
1d1ffb87 | 778 | return 0; |
779 | ||
fa649821 | 780 | if(attempt != 1) |
781 | error("Permission denied, please try again."); | |
782 | ||
f72e01a5 | 783 | snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ", |
188adeb2 | 784 | authctxt->server_user, authctxt->host); |
a306f2dd | 785 | password = read_passphrase(prompt, 0); |
786 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
188adeb2 | 787 | packet_put_cstring(authctxt->server_user); |
788 | packet_put_cstring(authctxt->service); | |
94ec8c6b | 789 | packet_put_cstring(authctxt->method->name); |
a306f2dd | 790 | packet_put_char(0); |
a6215e53 | 791 | packet_put_cstring(password); |
a306f2dd | 792 | memset(password, 0, strlen(password)); |
793 | xfree(password); | |
a6215e53 | 794 | packet_inject_ignore(64); |
a306f2dd | 795 | packet_send(); |
a306f2dd | 796 | return 1; |
797 | } | |
798 | ||
fee56204 | 799 | void |
800 | clear_auth_state(Authctxt *authctxt) | |
801 | { | |
802 | /* XXX clear authentication state */ | |
803 | if (authctxt->last_key != NULL && authctxt->last_key_hint == -1) { | |
804 | debug3("clear_auth_state: key_free %p", authctxt->last_key); | |
805 | key_free(authctxt->last_key); | |
806 | } | |
807 | authctxt->last_key = NULL; | |
808 | authctxt->last_key_hint = -2; | |
809 | authctxt->last_key_sign = NULL; | |
810 | } | |
811 | ||
2e73a022 | 812 | int |
188adeb2 | 813 | sign_and_send_pubkey(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback) |
a306f2dd | 814 | { |
815 | Buffer b; | |
1e3b8b07 | 816 | u_char *blob, *signature; |
a306f2dd | 817 | int bloblen, slen; |
74fc9186 | 818 | int skip = 0; |
2e73a022 | 819 | int ret = -1; |
94ec8c6b | 820 | int have_sig = 1; |
a306f2dd | 821 | |
cbc5abf9 | 822 | debug3("sign_and_send_pubkey"); |
fee56204 | 823 | |
fa08c86b | 824 | if (key_to_blob(k, &blob, &bloblen) == 0) { |
825 | /* we cannot handle this key */ | |
cbc5abf9 | 826 | debug3("sign_and_send_pubkey: cannot handle key"); |
fa08c86b | 827 | return 0; |
828 | } | |
a306f2dd | 829 | /* data to be signed */ |
830 | buffer_init(&b); | |
33de75a3 | 831 | if (datafellows & SSH_OLD_SESSIONID) { |
74fc9186 | 832 | buffer_append(&b, session_id2, session_id2_len); |
2b87da3b | 833 | skip = session_id2_len; |
33de75a3 | 834 | } else { |
835 | buffer_put_string(&b, session_id2, session_id2_len); | |
836 | skip = buffer_len(&b); | |
74fc9186 | 837 | } |
a306f2dd | 838 | buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); |
188adeb2 | 839 | buffer_put_cstring(&b, authctxt->server_user); |
d0c832f3 | 840 | buffer_put_cstring(&b, |
cbc5abf9 | 841 | datafellows & SSH_BUG_PKSERVICE ? |
d0c832f3 | 842 | "ssh-userauth" : |
188adeb2 | 843 | authctxt->service); |
cbc5abf9 | 844 | if (datafellows & SSH_BUG_PKAUTH) { |
845 | buffer_put_char(&b, have_sig); | |
846 | } else { | |
847 | buffer_put_cstring(&b, authctxt->method->name); | |
848 | buffer_put_char(&b, have_sig); | |
2b87da3b | 849 | buffer_put_cstring(&b, key_ssh_name(k)); |
cbc5abf9 | 850 | } |
a306f2dd | 851 | buffer_put_string(&b, blob, bloblen); |
a306f2dd | 852 | |
853 | /* generate signature */ | |
fee56204 | 854 | ret = (*sign_callback)(authctxt, k, &signature, &slen, |
855 | buffer_ptr(&b), buffer_len(&b)); | |
2e73a022 | 856 | if (ret == -1) { |
857 | xfree(blob); | |
858 | buffer_free(&b); | |
859 | return 0; | |
860 | } | |
fa08c86b | 861 | #ifdef DEBUG_PK |
a306f2dd | 862 | buffer_dump(&b); |
863 | #endif | |
cbc5abf9 | 864 | if (datafellows & SSH_BUG_PKSERVICE) { |
d0c832f3 | 865 | buffer_clear(&b); |
866 | buffer_append(&b, session_id2, session_id2_len); | |
fee56204 | 867 | skip = session_id2_len; |
d0c832f3 | 868 | buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); |
188adeb2 | 869 | buffer_put_cstring(&b, authctxt->server_user); |
870 | buffer_put_cstring(&b, authctxt->service); | |
94ec8c6b | 871 | buffer_put_cstring(&b, authctxt->method->name); |
872 | buffer_put_char(&b, have_sig); | |
cbc5abf9 | 873 | if (!(datafellows & SSH_BUG_PKAUTH)) |
2b87da3b | 874 | buffer_put_cstring(&b, key_ssh_name(k)); |
d0c832f3 | 875 | buffer_put_string(&b, blob, bloblen); |
876 | } | |
877 | xfree(blob); | |
fee56204 | 878 | |
a306f2dd | 879 | /* append signature */ |
880 | buffer_put_string(&b, signature, slen); | |
881 | xfree(signature); | |
882 | ||
883 | /* skip session id and packet type */ | |
74fc9186 | 884 | if (buffer_len(&b) < skip + 1) |
188adeb2 | 885 | fatal("userauth_pubkey: internal error"); |
74fc9186 | 886 | buffer_consume(&b, skip + 1); |
a306f2dd | 887 | |
888 | /* put remaining data from buffer into packet */ | |
889 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
890 | packet_put_raw(buffer_ptr(&b), buffer_len(&b)); | |
891 | buffer_free(&b); | |
a306f2dd | 892 | packet_send(); |
2e73a022 | 893 | |
894 | return 1; | |
4c8722d9 | 895 | } |
896 | ||
897 | int | |
fee56204 | 898 | send_pubkey_test(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback, |
899 | int hint) | |
4c8722d9 | 900 | { |
fee56204 | 901 | u_char *blob; |
902 | int bloblen, have_sig = 0; | |
4c8722d9 | 903 | |
fee56204 | 904 | debug3("send_pubkey_test"); |
905 | ||
906 | if (key_to_blob(k, &blob, &bloblen) == 0) { | |
907 | /* we cannot handle this key */ | |
908 | debug3("send_pubkey_test: cannot handle key"); | |
4c8722d9 | 909 | return 0; |
910 | } | |
fee56204 | 911 | /* register callback for USERAUTH_PK_OK message */ |
912 | authctxt->last_key_sign = sign_callback; | |
913 | authctxt->last_key_hint = hint; | |
914 | authctxt->last_key = k; | |
915 | dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok); | |
4c8722d9 | 916 | |
fee56204 | 917 | packet_start(SSH2_MSG_USERAUTH_REQUEST); |
918 | packet_put_cstring(authctxt->server_user); | |
919 | packet_put_cstring(authctxt->service); | |
920 | packet_put_cstring(authctxt->method->name); | |
921 | packet_put_char(have_sig); | |
922 | if (!(datafellows & SSH_BUG_PKAUTH)) | |
923 | packet_put_cstring(key_ssh_name(k)); | |
924 | packet_put_string(blob, bloblen); | |
925 | xfree(blob); | |
926 | packet_send(); | |
927 | return 1; | |
928 | } | |
929 | ||
930 | Key * | |
931 | load_identity_file(char *filename) | |
932 | { | |
933 | Key *private; | |
934 | char prompt[300], *passphrase; | |
aeaa3d9e | 935 | int quit, i; |
d156519a | 936 | struct stat st; |
fee56204 | 937 | |
d156519a | 938 | if (stat(filename, &st) < 0) { |
939 | debug3("no such identity: %s", filename); | |
940 | return NULL; | |
941 | } | |
aeaa3d9e | 942 | private = key_load_private_type(KEY_UNSPEC, filename, "", NULL); |
943 | if (private == NULL) { | |
944 | if (options.batch_mode) | |
fee56204 | 945 | return NULL; |
4c8722d9 | 946 | snprintf(prompt, sizeof prompt, |
fa08c86b | 947 | "Enter passphrase for key '%.100s': ", filename); |
188adeb2 | 948 | for (i = 0; i < options.number_of_password_prompts; i++) { |
949 | passphrase = read_passphrase(prompt, 0); | |
950 | if (strcmp(passphrase, "") != 0) { | |
aeaa3d9e | 951 | private = key_load_private_type(KEY_UNSPEC, filename, |
952 | passphrase, NULL); | |
fee56204 | 953 | quit = 0; |
188adeb2 | 954 | } else { |
955 | debug2("no passphrase given, try next key"); | |
fee56204 | 956 | quit = 1; |
188adeb2 | 957 | } |
958 | memset(passphrase, 0, strlen(passphrase)); | |
959 | xfree(passphrase); | |
aeaa3d9e | 960 | if (private != NULL || quit) |
188adeb2 | 961 | break; |
962 | debug2("bad passphrase given, try again..."); | |
963 | } | |
4c8722d9 | 964 | } |
fee56204 | 965 | return private; |
966 | } | |
967 | ||
968 | int | |
969 | identity_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp, | |
970 | u_char *data, int datalen) | |
971 | { | |
972 | Key *private; | |
973 | int idx, ret; | |
974 | ||
975 | idx = authctxt->last_key_hint; | |
976 | if (idx < 0) | |
977 | return -1; | |
978 | private = load_identity_file(options.identity_files[idx]); | |
979 | if (private == NULL) | |
980 | return -1; | |
981 | ret = key_sign(private, sigp, lenp, data, datalen); | |
982 | key_free(private); | |
2e73a022 | 983 | return ret; |
984 | } | |
985 | ||
1e3b8b07 | 986 | int agent_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp, |
987 | u_char *data, int datalen) | |
2e73a022 | 988 | { |
188adeb2 | 989 | return ssh_agent_sign(authctxt->agent, key, sigp, lenp, data, datalen); |
2e73a022 | 990 | } |
991 | ||
fee56204 | 992 | int key_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp, |
993 | u_char *data, int datalen) | |
994 | { | |
995 | return key_sign(key, sigp, lenp, data, datalen); | |
996 | } | |
997 | ||
2e73a022 | 998 | int |
188adeb2 | 999 | userauth_pubkey_agent(Authctxt *authctxt) |
2e73a022 | 1000 | { |
1001 | static int called = 0; | |
fa08c86b | 1002 | int ret = 0; |
2e73a022 | 1003 | char *comment; |
1004 | Key *k; | |
2e73a022 | 1005 | |
1006 | if (called == 0) { | |
fa08c86b | 1007 | if (ssh_get_num_identities(authctxt->agent, 2) == 0) |
1008 | debug2("userauth_pubkey_agent: no keys at all"); | |
188adeb2 | 1009 | called = 1; |
2e73a022 | 1010 | } |
fa08c86b | 1011 | k = ssh_get_next_identity(authctxt->agent, &comment, 2); |
188adeb2 | 1012 | if (k == NULL) { |
fa08c86b | 1013 | debug2("userauth_pubkey_agent: no more keys"); |
1014 | } else { | |
fee56204 | 1015 | debug("userauth_pubkey_agent: testing agent key %s", comment); |
fa08c86b | 1016 | xfree(comment); |
fee56204 | 1017 | ret = send_pubkey_test(authctxt, k, agent_sign_cb, -1); |
1018 | if (ret == 0) | |
1019 | key_free(k); | |
188adeb2 | 1020 | } |
fa08c86b | 1021 | if (ret == 0) |
1022 | debug2("userauth_pubkey_agent: no message sent"); | |
2e73a022 | 1023 | return ret; |
a306f2dd | 1024 | } |
1025 | ||
188adeb2 | 1026 | int |
1027 | userauth_pubkey(Authctxt *authctxt) | |
a306f2dd | 1028 | { |
188adeb2 | 1029 | static int idx = 0; |
1030 | int sent = 0; | |
fee56204 | 1031 | Key *key; |
1032 | char *filename; | |
188adeb2 | 1033 | |
fa08c86b | 1034 | if (authctxt->agent != NULL) { |
1035 | do { | |
1036 | sent = userauth_pubkey_agent(authctxt); | |
1037 | } while(!sent && authctxt->agent->howmany > 0); | |
1038 | } | |
1039 | while (!sent && idx < options.num_identity_files) { | |
fee56204 | 1040 | key = options.identity_keys[idx]; |
1041 | filename = options.identity_files[idx]; | |
1042 | if (key == NULL) { | |
1043 | debug("try privkey: %s", filename); | |
1044 | key = load_identity_file(filename); | |
1045 | if (key != NULL) { | |
1046 | sent = sign_and_send_pubkey(authctxt, key, | |
1047 | key_sign_cb); | |
1048 | key_free(key); | |
1049 | } | |
1050 | } else if (key->type != KEY_RSA1) { | |
1051 | debug("try pubkey: %s", filename); | |
1052 | sent = send_pubkey_test(authctxt, key, | |
1053 | identity_sign_cb, idx); | |
1054 | } | |
fa08c86b | 1055 | idx++; |
1056 | } | |
188adeb2 | 1057 | return sent; |
1058 | } | |
a306f2dd | 1059 | |
94ec8c6b | 1060 | /* |
1061 | * Send userauth request message specifying keyboard-interactive method. | |
1062 | */ | |
1063 | int | |
1064 | userauth_kbdint(Authctxt *authctxt) | |
1065 | { | |
1066 | static int attempt = 0; | |
1067 | ||
1068 | if (attempt++ >= options.number_of_password_prompts) | |
1069 | return 0; | |
1070 | ||
1071 | debug2("userauth_kbdint"); | |
1072 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
1073 | packet_put_cstring(authctxt->server_user); | |
1074 | packet_put_cstring(authctxt->service); | |
1075 | packet_put_cstring(authctxt->method->name); | |
1076 | packet_put_cstring(""); /* lang */ | |
1077 | packet_put_cstring(options.kbd_interactive_devices ? | |
1078 | options.kbd_interactive_devices : ""); | |
1079 | packet_send(); | |
94ec8c6b | 1080 | |
1081 | dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req); | |
1082 | return 1; | |
1083 | } | |
1084 | ||
1085 | /* | |
f72e01a5 | 1086 | * parse INFO_REQUEST, prompt user and send INFO_RESPONSE |
94ec8c6b | 1087 | */ |
1088 | void | |
1089 | input_userauth_info_req(int type, int plen, void *ctxt) | |
1090 | { | |
1091 | Authctxt *authctxt = ctxt; | |
f72e01a5 | 1092 | char *name, *inst, *lang, *prompt, *response; |
1e3b8b07 | 1093 | u_int num_prompts, i; |
94ec8c6b | 1094 | int echo = 0; |
1095 | ||
1096 | debug2("input_userauth_info_req"); | |
1097 | ||
1098 | if (authctxt == NULL) | |
1099 | fatal("input_userauth_info_req: no authentication context"); | |
1100 | ||
1101 | name = packet_get_string(NULL); | |
1102 | inst = packet_get_string(NULL); | |
1103 | lang = packet_get_string(NULL); | |
94ec8c6b | 1104 | if (strlen(name) > 0) |
1105 | cli_mesg(name); | |
94ec8c6b | 1106 | if (strlen(inst) > 0) |
1107 | cli_mesg(inst); | |
f72e01a5 | 1108 | xfree(name); |
94ec8c6b | 1109 | xfree(inst); |
f72e01a5 | 1110 | xfree(lang); |
94ec8c6b | 1111 | |
1112 | num_prompts = packet_get_int(); | |
1113 | /* | |
1114 | * Begin to build info response packet based on prompts requested. | |
1115 | * We commit to providing the correct number of responses, so if | |
1116 | * further on we run into a problem that prevents this, we have to | |
1117 | * be sure and clean this up and send a correct error response. | |
1118 | */ | |
1119 | packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE); | |
1120 | packet_put_int(num_prompts); | |
1121 | ||
1122 | for (i = 0; i < num_prompts; i++) { | |
1123 | prompt = packet_get_string(NULL); | |
1124 | echo = packet_get_char(); | |
1125 | ||
1126 | response = cli_prompt(prompt, echo); | |
1127 | ||
a6215e53 | 1128 | packet_put_cstring(response); |
94ec8c6b | 1129 | memset(response, 0, strlen(response)); |
1130 | xfree(response); | |
1131 | xfree(prompt); | |
1132 | } | |
1133 | packet_done(); /* done with parsing incoming message. */ | |
1134 | ||
a6215e53 | 1135 | packet_inject_ignore(64); |
94ec8c6b | 1136 | packet_send(); |
94ec8c6b | 1137 | } |
a306f2dd | 1138 | |
188adeb2 | 1139 | /* find auth method */ |
1140 | ||
188adeb2 | 1141 | /* |
1142 | * given auth method name, if configurable options permit this method fill | |
1143 | * in auth_ident field and return true, otherwise return false. | |
1144 | */ | |
1145 | int | |
1146 | authmethod_is_enabled(Authmethod *method) | |
1147 | { | |
1148 | if (method == NULL) | |
1149 | return 0; | |
1150 | /* return false if options indicate this method is disabled */ | |
1151 | if (method->enabled == NULL || *method->enabled == 0) | |
1152 | return 0; | |
1153 | /* return false if batch mode is enabled but method needs interactive mode */ | |
1154 | if (method->batch_flag != NULL && *method->batch_flag != 0) | |
1155 | return 0; | |
1156 | return 1; | |
1157 | } | |
a306f2dd | 1158 | |
188adeb2 | 1159 | Authmethod * |
1160 | authmethod_lookup(const char *name) | |
1161 | { | |
1162 | Authmethod *method = NULL; | |
1163 | if (name != NULL) | |
1164 | for (method = authmethods; method->name != NULL; method++) | |
1165 | if (strcmp(name, method->name) == 0) | |
1166 | return method; | |
1167 | debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); | |
1168 | return NULL; | |
1169 | } | |
1170 | ||
cab80f75 | 1171 | /* XXX internal state */ |
1172 | static Authmethod *current = NULL; | |
1173 | static char *supported = NULL; | |
1174 | static char *preferred = NULL; | |
188adeb2 | 1175 | /* |
1176 | * Given the authentication method list sent by the server, return the | |
1177 | * next method we should try. If the server initially sends a nil list, | |
cab80f75 | 1178 | * use a built-in default list. |
2b87da3b | 1179 | */ |
188adeb2 | 1180 | Authmethod * |
1181 | authmethod_get(char *authlist) | |
1182 | { | |
cab80f75 | 1183 | |
1184 | char *name = NULL; | |
1185 | int next; | |
2b87da3b | 1186 | |
188adeb2 | 1187 | /* Use a suitable default if we're passed a nil list. */ |
1188 | if (authlist == NULL || strlen(authlist) == 0) | |
cab80f75 | 1189 | authlist = options.preferred_authentications; |
1190 | ||
1191 | if (supported == NULL || strcmp(authlist, supported) != 0) { | |
1192 | debug3("start over, passed a different list %s", authlist); | |
1193 | if (supported != NULL) | |
1194 | xfree(supported); | |
1195 | supported = xstrdup(authlist); | |
1196 | preferred = options.preferred_authentications; | |
1197 | debug3("preferred %s", preferred); | |
1198 | current = NULL; | |
1199 | } else if (current != NULL && authmethod_is_enabled(current)) | |
1200 | return current; | |
188adeb2 | 1201 | |
cab80f75 | 1202 | for (;;) { |
1203 | if ((name = match_list(preferred, supported, &next)) == NULL) { | |
1204 | debug("no more auth methods to try"); | |
1205 | current = NULL; | |
1206 | return NULL; | |
1207 | } | |
1208 | preferred += next; | |
94ec8c6b | 1209 | debug3("authmethod_lookup %s", name); |
cab80f75 | 1210 | debug3("remaining preferred: %s", preferred); |
1211 | if ((current = authmethod_lookup(name)) != NULL && | |
1212 | authmethod_is_enabled(current)) { | |
94ec8c6b | 1213 | debug3("authmethod_is_enabled %s", name); |
cab80f75 | 1214 | debug("next auth method to try is %s", name); |
1215 | return current; | |
94ec8c6b | 1216 | } |
a306f2dd | 1217 | } |
cab80f75 | 1218 | } |
a22aff1f | 1219 | |
a22aff1f | 1220 | |
cab80f75 | 1221 | #define DELIM "," |
1222 | char * | |
1223 | authmethods_get(void) | |
1224 | { | |
1225 | Authmethod *method = NULL; | |
1226 | char buf[1024]; | |
1227 | ||
1228 | buf[0] = '\0'; | |
1229 | for (method = authmethods; method->name != NULL; method++) { | |
1230 | if (authmethod_is_enabled(method)) { | |
1231 | if (buf[0] != '\0') | |
1232 | strlcat(buf, DELIM, sizeof buf); | |
1233 | strlcat(buf, method->name, sizeof buf); | |
1234 | } | |
1235 | } | |
1236 | return xstrdup(buf); | |
a306f2dd | 1237 | } |