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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" | |
db1cd2f3 | 26 | RCSID("$OpenBSD: sshconnect2.c,v 1.57 2001/03/27 17:46:49 provos 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 | } | |
88 | if (options.compression) { | |
b2552997 | 89 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = |
94ec8c6b | 90 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib"; |
91 | } else { | |
b2552997 | 92 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = |
94ec8c6b | 93 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none"; |
94 | } | |
b2552997 | 95 | if (options.macs != NULL) { |
96 | myproposal[PROPOSAL_MAC_ALGS_CTOS] = | |
97 | myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; | |
98 | } | |
94ec8c6b | 99 | |
80cd07ae | 100 | myproposal[PROPOSAL_ENC_ALGS_STOC] = |
101 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); | |
102 | ||
94ec8c6b | 103 | /* buffers with raw kexinit messages */ |
104 | server_kexinit = xmalloc(sizeof(*server_kexinit)); | |
105 | buffer_init(server_kexinit); | |
106 | client_kexinit = kex_init(myproposal); | |
107 | ||
108 | /* algorithm negotiation */ | |
109 | kex_exchange_kexinit(client_kexinit, server_kexinit, sprop); | |
110 | kex = kex_choose_conf(myproposal, sprop, 0); | |
111 | for (i = 0; i < PROPOSAL_MAX; i++) | |
112 | xfree(sprop[i]); | |
113 | ||
114 | /* server authentication and session key agreement */ | |
115 | switch(kex->kex_type) { | |
116 | case DH_GRP1_SHA1: | |
117 | ssh_dh1_client(kex, host, hostaddr, | |
118 | client_kexinit, server_kexinit); | |
119 | break; | |
120 | case DH_GEX_SHA1: | |
121 | ssh_dhgex_client(kex, host, hostaddr, client_kexinit, | |
122 | server_kexinit); | |
123 | break; | |
124 | default: | |
125 | fatal("Unsupported key exchange %d", kex->kex_type); | |
126 | } | |
127 | ||
128 | buffer_free(client_kexinit); | |
129 | buffer_free(server_kexinit); | |
130 | xfree(client_kexinit); | |
131 | xfree(server_kexinit); | |
132 | ||
133 | debug("Wait SSH2_MSG_NEWKEYS."); | |
134 | packet_read_expect(&plen, SSH2_MSG_NEWKEYS); | |
135 | packet_done(); | |
136 | debug("GOT SSH2_MSG_NEWKEYS."); | |
137 | ||
138 | debug("send SSH2_MSG_NEWKEYS."); | |
139 | packet_start(SSH2_MSG_NEWKEYS); | |
140 | packet_send(); | |
141 | packet_write_wait(); | |
142 | debug("done: send SSH2_MSG_NEWKEYS."); | |
143 | ||
144 | #ifdef DEBUG_KEXDH | |
145 | /* send 1st encrypted/maced/compressed message */ | |
146 | packet_start(SSH2_MSG_IGNORE); | |
147 | packet_put_cstring("markus"); | |
148 | packet_send(); | |
149 | packet_write_wait(); | |
150 | #endif | |
151 | debug("done: KEX2."); | |
152 | } | |
153 | ||
154 | /* diffie-hellman-group1-sha1 */ | |
155 | ||
156 | void | |
2b87da3b | 157 | ssh_dh1_client(Kex *kex, char *host, struct sockaddr *hostaddr, |
94ec8c6b | 158 | Buffer *client_kexinit, Buffer *server_kexinit) |
a306f2dd | 159 | { |
188adeb2 | 160 | #ifdef DEBUG_KEXDH |
161 | int i; | |
162 | #endif | |
71276795 | 163 | int plen, dlen; |
1e3b8b07 | 164 | u_int klen, kout; |
a306f2dd | 165 | char *signature = NULL; |
1e3b8b07 | 166 | u_int slen; |
a306f2dd | 167 | char *server_host_key_blob = NULL; |
168 | Key *server_host_key; | |
1e3b8b07 | 169 | u_int sbloblen; |
a306f2dd | 170 | DH *dh; |
171 | BIGNUM *dh_server_pub = 0; | |
172 | BIGNUM *shared_secret = 0; | |
1e3b8b07 | 173 | u_char *kbuf; |
174 | u_char *hash; | |
a306f2dd | 175 | |
a306f2dd | 176 | debug("Sending SSH2_MSG_KEXDH_INIT."); |
a306f2dd | 177 | /* generate and send 'e', client DH public key */ |
178 | dh = dh_new_group1(); | |
7de5b06b | 179 | dh_gen_key(dh, kex->we_need * 8); |
a306f2dd | 180 | packet_start(SSH2_MSG_KEXDH_INIT); |
181 | packet_put_bignum2(dh->pub_key); | |
182 | packet_send(); | |
183 | packet_write_wait(); | |
184 | ||
185 | #ifdef DEBUG_KEXDH | |
186 | fprintf(stderr, "\np= "); | |
188adeb2 | 187 | BN_print_fp(stderr, dh->p); |
a306f2dd | 188 | fprintf(stderr, "\ng= "); |
188adeb2 | 189 | BN_print_fp(stderr, dh->g); |
a306f2dd | 190 | fprintf(stderr, "\npub= "); |
188adeb2 | 191 | BN_print_fp(stderr, dh->pub_key); |
a306f2dd | 192 | fprintf(stderr, "\n"); |
193 | DHparams_print_fp(stderr, dh); | |
194 | #endif | |
195 | ||
196 | debug("Wait SSH2_MSG_KEXDH_REPLY."); | |
197 | ||
71276795 | 198 | packet_read_expect(&plen, SSH2_MSG_KEXDH_REPLY); |
a306f2dd | 199 | |
200 | debug("Got SSH2_MSG_KEXDH_REPLY."); | |
201 | ||
202 | /* key, cert */ | |
203 | server_host_key_blob = packet_get_string(&sbloblen); | |
fa08c86b | 204 | server_host_key = key_from_blob(server_host_key_blob, sbloblen); |
a306f2dd | 205 | if (server_host_key == NULL) |
206 | fatal("cannot decode server_host_key_blob"); | |
207 | ||
208 | check_host_key(host, hostaddr, server_host_key, | |
94ec8c6b | 209 | options.user_hostfile2, options.system_hostfile2); |
a306f2dd | 210 | |
211 | /* DH paramter f, server public DH key */ | |
212 | dh_server_pub = BN_new(); | |
213 | if (dh_server_pub == NULL) | |
214 | fatal("dh_server_pub == NULL"); | |
215 | packet_get_bignum2(dh_server_pub, &dlen); | |
216 | ||
217 | #ifdef DEBUG_KEXDH | |
218 | fprintf(stderr, "\ndh_server_pub= "); | |
188adeb2 | 219 | BN_print_fp(stderr, dh_server_pub); |
a306f2dd | 220 | fprintf(stderr, "\n"); |
221 | debug("bits %d", BN_num_bits(dh_server_pub)); | |
222 | #endif | |
223 | ||
224 | /* signed H */ | |
225 | signature = packet_get_string(&slen); | |
226 | packet_done(); | |
227 | ||
228 | if (!dh_pub_is_valid(dh, dh_server_pub)) | |
229 | packet_disconnect("bad server public DH value"); | |
230 | ||
231 | klen = DH_size(dh); | |
232 | kbuf = xmalloc(klen); | |
233 | kout = DH_compute_key(kbuf, dh_server_pub, dh); | |
234 | #ifdef DEBUG_KEXDH | |
235 | debug("shared secret: len %d/%d", klen, kout); | |
236 | fprintf(stderr, "shared secret == "); | |
237 | for (i = 0; i< kout; i++) | |
238 | fprintf(stderr, "%02x", (kbuf[i])&0xff); | |
239 | fprintf(stderr, "\n"); | |
240 | #endif | |
241 | shared_secret = BN_new(); | |
242 | ||
243 | BN_bin2bn(kbuf, kout, shared_secret); | |
244 | memset(kbuf, 0, klen); | |
245 | xfree(kbuf); | |
246 | ||
247 | /* calc and verify H */ | |
248 | hash = kex_hash( | |
249 | client_version_string, | |
250 | server_version_string, | |
251 | buffer_ptr(client_kexinit), buffer_len(client_kexinit), | |
252 | buffer_ptr(server_kexinit), buffer_len(server_kexinit), | |
253 | server_host_key_blob, sbloblen, | |
254 | dh->pub_key, | |
255 | dh_server_pub, | |
256 | shared_secret | |
257 | ); | |
258 | xfree(server_host_key_blob); | |
71276795 | 259 | DH_free(dh); |
53a24016 | 260 | BN_free(dh_server_pub); |
a306f2dd | 261 | #ifdef DEBUG_KEXDH |
262 | fprintf(stderr, "hash == "); | |
263 | for (i = 0; i< 20; i++) | |
264 | fprintf(stderr, "%02x", (hash[i])&0xff); | |
265 | fprintf(stderr, "\n"); | |
266 | #endif | |
1e3b8b07 | 267 | if (key_verify(server_host_key, (u_char *)signature, slen, hash, 20) != 1) |
fa08c86b | 268 | fatal("key_verify failed for server_host_key"); |
a306f2dd | 269 | key_free(server_host_key); |
53a24016 | 270 | xfree(signature); |
a306f2dd | 271 | |
272 | kex_derive_keys(kex, hash, shared_secret); | |
53a24016 | 273 | BN_clear_free(shared_secret); |
a306f2dd | 274 | packet_set_kex(kex); |
275 | ||
a306f2dd | 276 | /* save session id */ |
277 | session_id2_len = 20; | |
278 | session_id2 = xmalloc(session_id2_len); | |
279 | memcpy(session_id2, hash, session_id2_len); | |
71276795 | 280 | } |
281 | ||
94ec8c6b | 282 | /* diffie-hellman-group-exchange-sha1 */ |
283 | ||
284 | /* | |
285 | * Estimates the group order for a Diffie-Hellman group that has an | |
286 | * attack complexity approximately the same as O(2**bits). Estimate | |
287 | * with: O(exp(1.9223 * (ln q)^(1/3) (ln ln q)^(2/3))) | |
288 | */ | |
289 | ||
290 | int | |
291 | dh_estimate(int bits) | |
292 | { | |
2b87da3b | 293 | |
94ec8c6b | 294 | if (bits < 64) |
295 | return (512); /* O(2**63) */ | |
296 | if (bits < 128) | |
297 | return (1024); /* O(2**86) */ | |
298 | if (bits < 192) | |
299 | return (2048); /* O(2**116) */ | |
300 | return (4096); /* O(2**156) */ | |
301 | } | |
302 | ||
71276795 | 303 | void |
94ec8c6b | 304 | ssh_dhgex_client(Kex *kex, char *host, struct sockaddr *hostaddr, |
305 | Buffer *client_kexinit, Buffer *server_kexinit) | |
71276795 | 306 | { |
94ec8c6b | 307 | #ifdef DEBUG_KEXDH |
308 | int i; | |
309 | #endif | |
310 | int plen, dlen; | |
1e3b8b07 | 311 | u_int klen, kout; |
94ec8c6b | 312 | char *signature = NULL; |
db1cd2f3 | 313 | u_int slen, nbits, min, max; |
94ec8c6b | 314 | char *server_host_key_blob = NULL; |
315 | Key *server_host_key; | |
1e3b8b07 | 316 | u_int sbloblen; |
94ec8c6b | 317 | DH *dh; |
318 | BIGNUM *dh_server_pub = 0; | |
319 | BIGNUM *shared_secret = 0; | |
320 | BIGNUM *p = 0, *g = 0; | |
1e3b8b07 | 321 | u_char *kbuf; |
322 | u_char *hash; | |
71276795 | 323 | |
7de5b06b | 324 | nbits = dh_estimate(kex->we_need * 8); |
71276795 | 325 | |
db1cd2f3 | 326 | if (datafellows & SSH_OLD_DHGEX) { |
327 | debug("Sending SSH2_MSG_KEX_DH_GEX_REQUEST_OLD."); | |
328 | ||
329 | /* Old GEX request */ | |
330 | packet_start(SSH2_MSG_KEX_DH_GEX_REQUEST_OLD); | |
331 | packet_put_int(nbits); | |
332 | min = DH_GRP_MIN; | |
333 | max = DH_GRP_MAX; | |
334 | } else { | |
335 | debug("Sending SSH2_MSG_KEX_DH_GEX_REQUEST."); | |
336 | ||
337 | /* New GEX request */ | |
338 | min = DH_GRP_MIN; | |
339 | max = MIN(DH_GRP_MAX, nbits * 1.25); | |
340 | ||
341 | packet_start(SSH2_MSG_KEX_DH_GEX_REQUEST); | |
342 | packet_put_int(min); | |
343 | packet_put_int(nbits); | |
344 | packet_put_int(max); | |
345 | } | |
94ec8c6b | 346 | packet_send(); |
347 | packet_write_wait(); | |
71276795 | 348 | |
94ec8c6b | 349 | #ifdef DEBUG_KEXDH |
db1cd2f3 | 350 | fprintf(stderr, "\nmin = %d, nbits = %d, max = %d", min, nbits, max); |
94ec8c6b | 351 | #endif |
71276795 | 352 | |
94ec8c6b | 353 | debug("Wait SSH2_MSG_KEX_DH_GEX_GROUP."); |
71276795 | 354 | |
94ec8c6b | 355 | packet_read_expect(&plen, SSH2_MSG_KEX_DH_GEX_GROUP); |
a306f2dd | 356 | |
94ec8c6b | 357 | debug("Got SSH2_MSG_KEX_DH_GEX_GROUP."); |
a306f2dd | 358 | |
94ec8c6b | 359 | if ((p = BN_new()) == NULL) |
360 | fatal("BN_new"); | |
361 | packet_get_bignum2(p, &dlen); | |
362 | if ((g = BN_new()) == NULL) | |
363 | fatal("BN_new"); | |
364 | packet_get_bignum2(g, &dlen); | |
db1cd2f3 | 365 | |
366 | if (BN_num_bits(p) < min || BN_num_bits(p) > max) | |
367 | fatal("DH_GEX group out of range: %d !< %d !< %d", | |
368 | min, BN_num_bits(p), max); | |
369 | ||
42f11eb2 | 370 | dh = dh_new_group(g, p); |
a306f2dd | 371 | |
7de5b06b | 372 | dh_gen_key(dh, kex->we_need * 8); |
3e1caa83 | 373 | |
a306f2dd | 374 | #ifdef DEBUG_KEXDH |
94ec8c6b | 375 | fprintf(stderr, "\np= "); |
376 | BN_print_fp(stderr, dh->p); | |
377 | fprintf(stderr, "\ng= "); | |
378 | BN_print_fp(stderr, dh->g); | |
379 | fprintf(stderr, "\npub= "); | |
380 | BN_print_fp(stderr, dh->pub_key); | |
381 | fprintf(stderr, "\n"); | |
382 | DHparams_print_fp(stderr, dh); | |
383 | #endif | |
384 | ||
385 | debug("Sending SSH2_MSG_KEX_DH_GEX_INIT."); | |
386 | /* generate and send 'e', client DH public key */ | |
387 | packet_start(SSH2_MSG_KEX_DH_GEX_INIT); | |
388 | packet_put_bignum2(dh->pub_key); | |
a306f2dd | 389 | packet_send(); |
390 | packet_write_wait(); | |
94ec8c6b | 391 | |
392 | debug("Wait SSH2_MSG_KEX_DH_GEX_REPLY."); | |
393 | ||
394 | packet_read_expect(&plen, SSH2_MSG_KEX_DH_GEX_REPLY); | |
395 | ||
396 | debug("Got SSH2_MSG_KEXDH_REPLY."); | |
397 | ||
398 | /* key, cert */ | |
399 | server_host_key_blob = packet_get_string(&sbloblen); | |
fa08c86b | 400 | server_host_key = key_from_blob(server_host_key_blob, sbloblen); |
94ec8c6b | 401 | if (server_host_key == NULL) |
402 | fatal("cannot decode server_host_key_blob"); | |
403 | ||
404 | check_host_key(host, hostaddr, server_host_key, | |
405 | options.user_hostfile2, options.system_hostfile2); | |
406 | ||
407 | /* DH paramter f, server public DH key */ | |
408 | dh_server_pub = BN_new(); | |
409 | if (dh_server_pub == NULL) | |
410 | fatal("dh_server_pub == NULL"); | |
411 | packet_get_bignum2(dh_server_pub, &dlen); | |
412 | ||
413 | #ifdef DEBUG_KEXDH | |
414 | fprintf(stderr, "\ndh_server_pub= "); | |
415 | BN_print_fp(stderr, dh_server_pub); | |
416 | fprintf(stderr, "\n"); | |
417 | debug("bits %d", BN_num_bits(dh_server_pub)); | |
a306f2dd | 418 | #endif |
94ec8c6b | 419 | |
420 | /* signed H */ | |
421 | signature = packet_get_string(&slen); | |
422 | packet_done(); | |
423 | ||
424 | if (!dh_pub_is_valid(dh, dh_server_pub)) | |
425 | packet_disconnect("bad server public DH value"); | |
426 | ||
427 | klen = DH_size(dh); | |
428 | kbuf = xmalloc(klen); | |
429 | kout = DH_compute_key(kbuf, dh_server_pub, dh); | |
430 | #ifdef DEBUG_KEXDH | |
431 | debug("shared secret: len %d/%d", klen, kout); | |
432 | fprintf(stderr, "shared secret == "); | |
433 | for (i = 0; i< kout; i++) | |
434 | fprintf(stderr, "%02x", (kbuf[i])&0xff); | |
435 | fprintf(stderr, "\n"); | |
436 | #endif | |
437 | shared_secret = BN_new(); | |
438 | ||
439 | BN_bin2bn(kbuf, kout, shared_secret); | |
440 | memset(kbuf, 0, klen); | |
441 | xfree(kbuf); | |
442 | ||
443 | /* calc and verify H */ | |
444 | hash = kex_hash_gex( | |
445 | client_version_string, | |
446 | server_version_string, | |
447 | buffer_ptr(client_kexinit), buffer_len(client_kexinit), | |
448 | buffer_ptr(server_kexinit), buffer_len(server_kexinit), | |
449 | server_host_key_blob, sbloblen, | |
2b87da3b | 450 | nbits, dh->p, dh->g, |
94ec8c6b | 451 | dh->pub_key, |
452 | dh_server_pub, | |
453 | shared_secret | |
454 | ); | |
455 | xfree(server_host_key_blob); | |
456 | DH_free(dh); | |
53a24016 | 457 | BN_free(dh_server_pub); |
94ec8c6b | 458 | #ifdef DEBUG_KEXDH |
459 | fprintf(stderr, "hash == "); | |
460 | for (i = 0; i< 20; i++) | |
461 | fprintf(stderr, "%02x", (hash[i])&0xff); | |
462 | fprintf(stderr, "\n"); | |
463 | #endif | |
1e3b8b07 | 464 | if (key_verify(server_host_key, (u_char *)signature, slen, hash, 20) != 1) |
fa08c86b | 465 | fatal("key_verify failed for server_host_key"); |
94ec8c6b | 466 | key_free(server_host_key); |
53a24016 | 467 | xfree(signature); |
94ec8c6b | 468 | |
469 | kex_derive_keys(kex, hash, shared_secret); | |
53a24016 | 470 | BN_clear_free(shared_secret); |
94ec8c6b | 471 | packet_set_kex(kex); |
472 | ||
473 | /* save session id */ | |
474 | session_id2_len = 20; | |
475 | session_id2 = xmalloc(session_id2_len); | |
476 | memcpy(session_id2, hash, session_id2_len); | |
a306f2dd | 477 | } |
71276795 | 478 | |
a306f2dd | 479 | /* |
480 | * Authenticate user | |
481 | */ | |
188adeb2 | 482 | |
483 | typedef struct Authctxt Authctxt; | |
484 | typedef struct Authmethod Authmethod; | |
485 | ||
486 | typedef int sign_cb_fn( | |
487 | Authctxt *authctxt, Key *key, | |
1e3b8b07 | 488 | u_char **sigp, int *lenp, u_char *data, int datalen); |
188adeb2 | 489 | |
490 | struct Authctxt { | |
491 | const char *server_user; | |
492 | const char *host; | |
493 | const char *service; | |
494 | AuthenticationConnection *agent; | |
188adeb2 | 495 | Authmethod *method; |
94ec8c6b | 496 | int success; |
fee56204 | 497 | char *authlist; |
498 | Key *last_key; | |
499 | sign_cb_fn *last_key_sign; | |
500 | int last_key_hint; | |
188adeb2 | 501 | }; |
502 | struct Authmethod { | |
503 | char *name; /* string to compare against server's list */ | |
504 | int (*userauth)(Authctxt *authctxt); | |
505 | int *enabled; /* flag in option struct that enables method */ | |
506 | int *batch_flag; /* flag in option struct that disables method */ | |
507 | }; | |
508 | ||
509 | void input_userauth_success(int type, int plen, void *ctxt); | |
510 | void input_userauth_failure(int type, int plen, void *ctxt); | |
9616313f | 511 | void input_userauth_banner(int type, int plen, void *ctxt); |
188adeb2 | 512 | void input_userauth_error(int type, int plen, void *ctxt); |
94ec8c6b | 513 | void input_userauth_info_req(int type, int plen, void *ctxt); |
fee56204 | 514 | void input_userauth_pk_ok(int type, int plen, void *ctxt); |
94ec8c6b | 515 | |
516 | int userauth_none(Authctxt *authctxt); | |
188adeb2 | 517 | int userauth_pubkey(Authctxt *authctxt); |
518 | int userauth_passwd(Authctxt *authctxt); | |
94ec8c6b | 519 | int userauth_kbdint(Authctxt *authctxt); |
188adeb2 | 520 | |
fee56204 | 521 | void userauth(Authctxt *authctxt, char *authlist); |
522 | ||
523 | int | |
524 | sign_and_send_pubkey(Authctxt *authctxt, Key *k, | |
525 | sign_cb_fn *sign_callback); | |
526 | void clear_auth_state(Authctxt *authctxt); | |
527 | ||
94ec8c6b | 528 | Authmethod *authmethod_get(char *authlist); |
529 | Authmethod *authmethod_lookup(const char *name); | |
cab80f75 | 530 | char *authmethods_get(void); |
188adeb2 | 531 | |
532 | Authmethod authmethods[] = { | |
533 | {"publickey", | |
534 | userauth_pubkey, | |
fa08c86b | 535 | &options.pubkey_authentication, |
188adeb2 | 536 | NULL}, |
537 | {"password", | |
538 | userauth_passwd, | |
539 | &options.password_authentication, | |
540 | &options.batch_mode}, | |
94ec8c6b | 541 | {"keyboard-interactive", |
542 | userauth_kbdint, | |
543 | &options.kbd_interactive_authentication, | |
544 | &options.batch_mode}, | |
545 | {"none", | |
546 | userauth_none, | |
547 | NULL, | |
548 | NULL}, | |
188adeb2 | 549 | {NULL, NULL, NULL, NULL} |
550 | }; | |
551 | ||
552 | void | |
553 | ssh_userauth2(const char *server_user, char *host) | |
554 | { | |
555 | Authctxt authctxt; | |
556 | int type; | |
557 | int plen; | |
558 | ||
d464095c | 559 | if (options.challenge_reponse_authentication) |
560 | options.kbd_interactive_authentication = 1; | |
561 | ||
188adeb2 | 562 | debug("send SSH2_MSG_SERVICE_REQUEST"); |
563 | packet_start(SSH2_MSG_SERVICE_REQUEST); | |
564 | packet_put_cstring("ssh-userauth"); | |
565 | packet_send(); | |
566 | packet_write_wait(); | |
567 | type = packet_read(&plen); | |
568 | if (type != SSH2_MSG_SERVICE_ACCEPT) { | |
569 | fatal("denied SSH2_MSG_SERVICE_ACCEPT: %d", type); | |
570 | } | |
571 | if (packet_remaining() > 0) { | |
572 | char *reply = packet_get_string(&plen); | |
573 | debug("service_accept: %s", reply); | |
574 | xfree(reply); | |
188adeb2 | 575 | } else { |
576 | debug("buggy server: service_accept w/o service"); | |
577 | } | |
578 | packet_done(); | |
579 | debug("got SSH2_MSG_SERVICE_ACCEPT"); | |
580 | ||
cab80f75 | 581 | if (options.preferred_authentications == NULL) |
582 | options.preferred_authentications = authmethods_get(); | |
583 | ||
188adeb2 | 584 | /* setup authentication context */ |
585 | authctxt.agent = ssh_get_authentication_connection(); | |
586 | authctxt.server_user = server_user; | |
587 | authctxt.host = host; | |
588 | authctxt.service = "ssh-connection"; /* service name */ | |
589 | authctxt.success = 0; | |
94ec8c6b | 590 | authctxt.method = authmethod_lookup("none"); |
fee56204 | 591 | authctxt.authlist = NULL; |
94ec8c6b | 592 | if (authctxt.method == NULL) |
593 | fatal("ssh_userauth2: internal error: cannot send userauth none request"); | |
188adeb2 | 594 | |
595 | /* initial userauth request */ | |
94ec8c6b | 596 | userauth_none(&authctxt); |
188adeb2 | 597 | |
598 | dispatch_init(&input_userauth_error); | |
599 | dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); | |
600 | dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure); | |
9616313f | 601 | dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner); |
188adeb2 | 602 | dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */ |
603 | ||
604 | if (authctxt.agent != NULL) | |
605 | ssh_close_authentication_connection(authctxt.agent); | |
606 | ||
8abcdba4 | 607 | debug("ssh-userauth2 successful: method %s", authctxt.method->name); |
188adeb2 | 608 | } |
609 | void | |
fee56204 | 610 | userauth(Authctxt *authctxt, char *authlist) |
611 | { | |
612 | if (authlist == NULL) { | |
613 | authlist = authctxt->authlist; | |
614 | } else { | |
615 | if (authctxt->authlist) | |
616 | xfree(authctxt->authlist); | |
617 | authctxt->authlist = authlist; | |
618 | } | |
619 | for (;;) { | |
620 | Authmethod *method = authmethod_get(authlist); | |
621 | if (method == NULL) | |
622 | fatal("Permission denied (%s).", authlist); | |
623 | authctxt->method = method; | |
624 | if (method->userauth(authctxt) != 0) { | |
625 | debug2("we sent a %s packet, wait for reply", method->name); | |
626 | break; | |
627 | } else { | |
628 | debug2("we did not send a packet, disable method"); | |
629 | method->enabled = NULL; | |
630 | } | |
631 | } | |
632 | } | |
633 | void | |
188adeb2 | 634 | input_userauth_error(int type, int plen, void *ctxt) |
635 | { | |
9616313f | 636 | fatal("input_userauth_error: bad message during authentication: " |
637 | "type %d", type); | |
638 | } | |
639 | void | |
640 | input_userauth_banner(int type, int plen, void *ctxt) | |
641 | { | |
642 | char *msg, *lang; | |
643 | debug3("input_userauth_banner"); | |
644 | msg = packet_get_string(NULL); | |
645 | lang = packet_get_string(NULL); | |
646 | fprintf(stderr, "%s", msg); | |
647 | xfree(msg); | |
648 | xfree(lang); | |
188adeb2 | 649 | } |
650 | void | |
651 | input_userauth_success(int type, int plen, void *ctxt) | |
652 | { | |
653 | Authctxt *authctxt = ctxt; | |
654 | if (authctxt == NULL) | |
655 | fatal("input_userauth_success: no authentication context"); | |
fee56204 | 656 | if (authctxt->authlist) |
657 | xfree(authctxt->authlist); | |
658 | clear_auth_state(authctxt); | |
188adeb2 | 659 | authctxt->success = 1; /* break out */ |
660 | } | |
661 | void | |
662 | input_userauth_failure(int type, int plen, void *ctxt) | |
663 | { | |
188adeb2 | 664 | Authctxt *authctxt = ctxt; |
665 | char *authlist = NULL; | |
666 | int partial; | |
188adeb2 | 667 | |
668 | if (authctxt == NULL) | |
669 | fatal("input_userauth_failure: no authentication context"); | |
670 | ||
94ec8c6b | 671 | authlist = packet_get_string(NULL); |
188adeb2 | 672 | partial = packet_get_char(); |
673 | packet_done(); | |
674 | ||
675 | if (partial != 0) | |
f72e01a5 | 676 | log("Authenticated with partial success."); |
188adeb2 | 677 | debug("authentications that can continue: %s", authlist); |
678 | ||
fee56204 | 679 | clear_auth_state(authctxt); |
680 | userauth(authctxt, authlist); | |
681 | } | |
682 | void | |
683 | input_userauth_pk_ok(int type, int plen, void *ctxt) | |
684 | { | |
685 | Authctxt *authctxt = ctxt; | |
686 | Key *key = NULL; | |
687 | Buffer b; | |
688 | int alen, blen, pktype, sent = 0; | |
22138a36 | 689 | char *pkalg, *pkblob, *fp; |
fee56204 | 690 | |
691 | if (authctxt == NULL) | |
692 | fatal("input_userauth_pk_ok: no authentication context"); | |
693 | if (datafellows & SSH_BUG_PKOK) { | |
694 | /* this is similar to SSH_BUG_PKAUTH */ | |
695 | debug2("input_userauth_pk_ok: SSH_BUG_PKOK"); | |
696 | pkblob = packet_get_string(&blen); | |
697 | buffer_init(&b); | |
698 | buffer_append(&b, pkblob, blen); | |
699 | pkalg = buffer_get_string(&b, &alen); | |
700 | buffer_free(&b); | |
701 | } else { | |
702 | pkalg = packet_get_string(&alen); | |
703 | pkblob = packet_get_string(&blen); | |
704 | } | |
705 | packet_done(); | |
706 | ||
707 | debug("input_userauth_pk_ok: pkalg %s blen %d lastkey %p hint %d", | |
708 | pkalg, blen, authctxt->last_key, authctxt->last_key_hint); | |
709 | ||
710 | do { | |
711 | if (authctxt->last_key == NULL || | |
712 | authctxt->last_key_sign == NULL) { | |
713 | debug("no last key or no sign cb"); | |
188adeb2 | 714 | break; |
188adeb2 | 715 | } |
fee56204 | 716 | if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) { |
717 | debug("unknown pkalg %s", pkalg); | |
718 | break; | |
719 | } | |
720 | if ((key = key_from_blob(pkblob, blen)) == NULL) { | |
721 | debug("no key from blob. pkalg %s", pkalg); | |
722 | break; | |
723 | } | |
22138a36 | 724 | fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX); |
725 | debug2("input_userauth_pk_ok: fp %s", fp); | |
726 | xfree(fp); | |
fee56204 | 727 | if (!key_equal(key, authctxt->last_key)) { |
728 | debug("key != last_key"); | |
729 | break; | |
730 | } | |
731 | sent = sign_and_send_pubkey(authctxt, key, | |
732 | authctxt->last_key_sign); | |
733 | } while(0); | |
734 | ||
735 | if (key != NULL) | |
736 | key_free(key); | |
737 | xfree(pkalg); | |
738 | xfree(pkblob); | |
739 | ||
740 | /* unregister */ | |
741 | clear_auth_state(authctxt); | |
742 | dispatch_set(SSH2_MSG_USERAUTH_PK_OK, NULL); | |
743 | ||
744 | /* try another method if we did not send a packet*/ | |
745 | if (sent == 0) | |
746 | userauth(authctxt, NULL); | |
747 | ||
188adeb2 | 748 | } |
749 | ||
94ec8c6b | 750 | int |
751 | userauth_none(Authctxt *authctxt) | |
752 | { | |
753 | /* initial userauth request */ | |
754 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
755 | packet_put_cstring(authctxt->server_user); | |
756 | packet_put_cstring(authctxt->service); | |
757 | packet_put_cstring(authctxt->method->name); | |
758 | packet_send(); | |
94ec8c6b | 759 | return 1; |
760 | } | |
761 | ||
a306f2dd | 762 | int |
188adeb2 | 763 | userauth_passwd(Authctxt *authctxt) |
a306f2dd | 764 | { |
1d1ffb87 | 765 | static int attempt = 0; |
a306f2dd | 766 | char prompt[80]; |
767 | char *password; | |
768 | ||
fa649821 | 769 | if (attempt++ >= options.number_of_password_prompts) |
1d1ffb87 | 770 | return 0; |
771 | ||
fa649821 | 772 | if(attempt != 1) |
773 | error("Permission denied, please try again."); | |
774 | ||
f72e01a5 | 775 | snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ", |
188adeb2 | 776 | authctxt->server_user, authctxt->host); |
a306f2dd | 777 | password = read_passphrase(prompt, 0); |
778 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
188adeb2 | 779 | packet_put_cstring(authctxt->server_user); |
780 | packet_put_cstring(authctxt->service); | |
94ec8c6b | 781 | packet_put_cstring(authctxt->method->name); |
a306f2dd | 782 | packet_put_char(0); |
a6215e53 | 783 | packet_put_cstring(password); |
a306f2dd | 784 | memset(password, 0, strlen(password)); |
785 | xfree(password); | |
a6215e53 | 786 | packet_inject_ignore(64); |
a306f2dd | 787 | packet_send(); |
a306f2dd | 788 | return 1; |
789 | } | |
790 | ||
fee56204 | 791 | void |
792 | clear_auth_state(Authctxt *authctxt) | |
793 | { | |
794 | /* XXX clear authentication state */ | |
795 | if (authctxt->last_key != NULL && authctxt->last_key_hint == -1) { | |
796 | debug3("clear_auth_state: key_free %p", authctxt->last_key); | |
797 | key_free(authctxt->last_key); | |
798 | } | |
799 | authctxt->last_key = NULL; | |
800 | authctxt->last_key_hint = -2; | |
801 | authctxt->last_key_sign = NULL; | |
802 | } | |
803 | ||
2e73a022 | 804 | int |
188adeb2 | 805 | sign_and_send_pubkey(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback) |
a306f2dd | 806 | { |
807 | Buffer b; | |
1e3b8b07 | 808 | u_char *blob, *signature; |
a306f2dd | 809 | int bloblen, slen; |
74fc9186 | 810 | int skip = 0; |
2e73a022 | 811 | int ret = -1; |
94ec8c6b | 812 | int have_sig = 1; |
a306f2dd | 813 | |
cbc5abf9 | 814 | debug3("sign_and_send_pubkey"); |
fee56204 | 815 | |
fa08c86b | 816 | if (key_to_blob(k, &blob, &bloblen) == 0) { |
817 | /* we cannot handle this key */ | |
cbc5abf9 | 818 | debug3("sign_and_send_pubkey: cannot handle key"); |
fa08c86b | 819 | return 0; |
820 | } | |
a306f2dd | 821 | /* data to be signed */ |
822 | buffer_init(&b); | |
33de75a3 | 823 | if (datafellows & SSH_OLD_SESSIONID) { |
74fc9186 | 824 | buffer_append(&b, session_id2, session_id2_len); |
2b87da3b | 825 | skip = session_id2_len; |
33de75a3 | 826 | } else { |
827 | buffer_put_string(&b, session_id2, session_id2_len); | |
828 | skip = buffer_len(&b); | |
74fc9186 | 829 | } |
a306f2dd | 830 | buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); |
188adeb2 | 831 | buffer_put_cstring(&b, authctxt->server_user); |
d0c832f3 | 832 | buffer_put_cstring(&b, |
cbc5abf9 | 833 | datafellows & SSH_BUG_PKSERVICE ? |
d0c832f3 | 834 | "ssh-userauth" : |
188adeb2 | 835 | authctxt->service); |
cbc5abf9 | 836 | if (datafellows & SSH_BUG_PKAUTH) { |
837 | buffer_put_char(&b, have_sig); | |
838 | } else { | |
839 | buffer_put_cstring(&b, authctxt->method->name); | |
840 | buffer_put_char(&b, have_sig); | |
2b87da3b | 841 | buffer_put_cstring(&b, key_ssh_name(k)); |
cbc5abf9 | 842 | } |
a306f2dd | 843 | buffer_put_string(&b, blob, bloblen); |
a306f2dd | 844 | |
845 | /* generate signature */ | |
fee56204 | 846 | ret = (*sign_callback)(authctxt, k, &signature, &slen, |
847 | buffer_ptr(&b), buffer_len(&b)); | |
2e73a022 | 848 | if (ret == -1) { |
849 | xfree(blob); | |
850 | buffer_free(&b); | |
851 | return 0; | |
852 | } | |
fa08c86b | 853 | #ifdef DEBUG_PK |
a306f2dd | 854 | buffer_dump(&b); |
855 | #endif | |
cbc5abf9 | 856 | if (datafellows & SSH_BUG_PKSERVICE) { |
d0c832f3 | 857 | buffer_clear(&b); |
858 | buffer_append(&b, session_id2, session_id2_len); | |
fee56204 | 859 | skip = session_id2_len; |
d0c832f3 | 860 | buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); |
188adeb2 | 861 | buffer_put_cstring(&b, authctxt->server_user); |
862 | buffer_put_cstring(&b, authctxt->service); | |
94ec8c6b | 863 | buffer_put_cstring(&b, authctxt->method->name); |
864 | buffer_put_char(&b, have_sig); | |
cbc5abf9 | 865 | if (!(datafellows & SSH_BUG_PKAUTH)) |
2b87da3b | 866 | buffer_put_cstring(&b, key_ssh_name(k)); |
d0c832f3 | 867 | buffer_put_string(&b, blob, bloblen); |
868 | } | |
869 | xfree(blob); | |
fee56204 | 870 | |
a306f2dd | 871 | /* append signature */ |
872 | buffer_put_string(&b, signature, slen); | |
873 | xfree(signature); | |
874 | ||
875 | /* skip session id and packet type */ | |
74fc9186 | 876 | if (buffer_len(&b) < skip + 1) |
188adeb2 | 877 | fatal("userauth_pubkey: internal error"); |
74fc9186 | 878 | buffer_consume(&b, skip + 1); |
a306f2dd | 879 | |
880 | /* put remaining data from buffer into packet */ | |
881 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
882 | packet_put_raw(buffer_ptr(&b), buffer_len(&b)); | |
883 | buffer_free(&b); | |
a306f2dd | 884 | packet_send(); |
2e73a022 | 885 | |
886 | return 1; | |
4c8722d9 | 887 | } |
888 | ||
889 | int | |
fee56204 | 890 | send_pubkey_test(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback, |
891 | int hint) | |
4c8722d9 | 892 | { |
fee56204 | 893 | u_char *blob; |
894 | int bloblen, have_sig = 0; | |
4c8722d9 | 895 | |
fee56204 | 896 | debug3("send_pubkey_test"); |
897 | ||
898 | if (key_to_blob(k, &blob, &bloblen) == 0) { | |
899 | /* we cannot handle this key */ | |
900 | debug3("send_pubkey_test: cannot handle key"); | |
4c8722d9 | 901 | return 0; |
902 | } | |
fee56204 | 903 | /* register callback for USERAUTH_PK_OK message */ |
904 | authctxt->last_key_sign = sign_callback; | |
905 | authctxt->last_key_hint = hint; | |
906 | authctxt->last_key = k; | |
907 | dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok); | |
4c8722d9 | 908 | |
fee56204 | 909 | packet_start(SSH2_MSG_USERAUTH_REQUEST); |
910 | packet_put_cstring(authctxt->server_user); | |
911 | packet_put_cstring(authctxt->service); | |
912 | packet_put_cstring(authctxt->method->name); | |
913 | packet_put_char(have_sig); | |
914 | if (!(datafellows & SSH_BUG_PKAUTH)) | |
915 | packet_put_cstring(key_ssh_name(k)); | |
916 | packet_put_string(blob, bloblen); | |
917 | xfree(blob); | |
918 | packet_send(); | |
919 | return 1; | |
920 | } | |
921 | ||
922 | Key * | |
923 | load_identity_file(char *filename) | |
924 | { | |
925 | Key *private; | |
926 | char prompt[300], *passphrase; | |
aeaa3d9e | 927 | int quit, i; |
d156519a | 928 | struct stat st; |
fee56204 | 929 | |
d156519a | 930 | if (stat(filename, &st) < 0) { |
931 | debug3("no such identity: %s", filename); | |
932 | return NULL; | |
933 | } | |
aeaa3d9e | 934 | private = key_load_private_type(KEY_UNSPEC, filename, "", NULL); |
935 | if (private == NULL) { | |
936 | if (options.batch_mode) | |
fee56204 | 937 | return NULL; |
4c8722d9 | 938 | snprintf(prompt, sizeof prompt, |
fa08c86b | 939 | "Enter passphrase for key '%.100s': ", filename); |
188adeb2 | 940 | for (i = 0; i < options.number_of_password_prompts; i++) { |
941 | passphrase = read_passphrase(prompt, 0); | |
942 | if (strcmp(passphrase, "") != 0) { | |
aeaa3d9e | 943 | private = key_load_private_type(KEY_UNSPEC, filename, |
944 | passphrase, NULL); | |
fee56204 | 945 | quit = 0; |
188adeb2 | 946 | } else { |
947 | debug2("no passphrase given, try next key"); | |
fee56204 | 948 | quit = 1; |
188adeb2 | 949 | } |
950 | memset(passphrase, 0, strlen(passphrase)); | |
951 | xfree(passphrase); | |
aeaa3d9e | 952 | if (private != NULL || quit) |
188adeb2 | 953 | break; |
954 | debug2("bad passphrase given, try again..."); | |
955 | } | |
4c8722d9 | 956 | } |
fee56204 | 957 | return private; |
958 | } | |
959 | ||
960 | int | |
961 | identity_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp, | |
962 | u_char *data, int datalen) | |
963 | { | |
964 | Key *private; | |
965 | int idx, ret; | |
966 | ||
967 | idx = authctxt->last_key_hint; | |
968 | if (idx < 0) | |
969 | return -1; | |
970 | private = load_identity_file(options.identity_files[idx]); | |
971 | if (private == NULL) | |
972 | return -1; | |
973 | ret = key_sign(private, sigp, lenp, data, datalen); | |
974 | key_free(private); | |
2e73a022 | 975 | return ret; |
976 | } | |
977 | ||
1e3b8b07 | 978 | int agent_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp, |
979 | u_char *data, int datalen) | |
2e73a022 | 980 | { |
188adeb2 | 981 | return ssh_agent_sign(authctxt->agent, key, sigp, lenp, data, datalen); |
2e73a022 | 982 | } |
983 | ||
fee56204 | 984 | int key_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp, |
985 | u_char *data, int datalen) | |
986 | { | |
987 | return key_sign(key, sigp, lenp, data, datalen); | |
988 | } | |
989 | ||
2e73a022 | 990 | int |
188adeb2 | 991 | userauth_pubkey_agent(Authctxt *authctxt) |
2e73a022 | 992 | { |
993 | static int called = 0; | |
fa08c86b | 994 | int ret = 0; |
2e73a022 | 995 | char *comment; |
996 | Key *k; | |
2e73a022 | 997 | |
998 | if (called == 0) { | |
fa08c86b | 999 | if (ssh_get_num_identities(authctxt->agent, 2) == 0) |
1000 | debug2("userauth_pubkey_agent: no keys at all"); | |
188adeb2 | 1001 | called = 1; |
2e73a022 | 1002 | } |
fa08c86b | 1003 | k = ssh_get_next_identity(authctxt->agent, &comment, 2); |
188adeb2 | 1004 | if (k == NULL) { |
fa08c86b | 1005 | debug2("userauth_pubkey_agent: no more keys"); |
1006 | } else { | |
fee56204 | 1007 | debug("userauth_pubkey_agent: testing agent key %s", comment); |
fa08c86b | 1008 | xfree(comment); |
fee56204 | 1009 | ret = send_pubkey_test(authctxt, k, agent_sign_cb, -1); |
1010 | if (ret == 0) | |
1011 | key_free(k); | |
188adeb2 | 1012 | } |
fa08c86b | 1013 | if (ret == 0) |
1014 | debug2("userauth_pubkey_agent: no message sent"); | |
2e73a022 | 1015 | return ret; |
a306f2dd | 1016 | } |
1017 | ||
188adeb2 | 1018 | int |
1019 | userauth_pubkey(Authctxt *authctxt) | |
a306f2dd | 1020 | { |
188adeb2 | 1021 | static int idx = 0; |
1022 | int sent = 0; | |
fee56204 | 1023 | Key *key; |
1024 | char *filename; | |
188adeb2 | 1025 | |
fa08c86b | 1026 | if (authctxt->agent != NULL) { |
1027 | do { | |
1028 | sent = userauth_pubkey_agent(authctxt); | |
1029 | } while(!sent && authctxt->agent->howmany > 0); | |
1030 | } | |
1031 | while (!sent && idx < options.num_identity_files) { | |
fee56204 | 1032 | key = options.identity_keys[idx]; |
1033 | filename = options.identity_files[idx]; | |
1034 | if (key == NULL) { | |
1035 | debug("try privkey: %s", filename); | |
1036 | key = load_identity_file(filename); | |
1037 | if (key != NULL) { | |
1038 | sent = sign_and_send_pubkey(authctxt, key, | |
1039 | key_sign_cb); | |
1040 | key_free(key); | |
1041 | } | |
1042 | } else if (key->type != KEY_RSA1) { | |
1043 | debug("try pubkey: %s", filename); | |
1044 | sent = send_pubkey_test(authctxt, key, | |
1045 | identity_sign_cb, idx); | |
1046 | } | |
fa08c86b | 1047 | idx++; |
1048 | } | |
188adeb2 | 1049 | return sent; |
1050 | } | |
a306f2dd | 1051 | |
94ec8c6b | 1052 | /* |
1053 | * Send userauth request message specifying keyboard-interactive method. | |
1054 | */ | |
1055 | int | |
1056 | userauth_kbdint(Authctxt *authctxt) | |
1057 | { | |
1058 | static int attempt = 0; | |
1059 | ||
1060 | if (attempt++ >= options.number_of_password_prompts) | |
1061 | return 0; | |
1062 | ||
1063 | debug2("userauth_kbdint"); | |
1064 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
1065 | packet_put_cstring(authctxt->server_user); | |
1066 | packet_put_cstring(authctxt->service); | |
1067 | packet_put_cstring(authctxt->method->name); | |
1068 | packet_put_cstring(""); /* lang */ | |
1069 | packet_put_cstring(options.kbd_interactive_devices ? | |
1070 | options.kbd_interactive_devices : ""); | |
1071 | packet_send(); | |
94ec8c6b | 1072 | |
1073 | dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req); | |
1074 | return 1; | |
1075 | } | |
1076 | ||
1077 | /* | |
f72e01a5 | 1078 | * parse INFO_REQUEST, prompt user and send INFO_RESPONSE |
94ec8c6b | 1079 | */ |
1080 | void | |
1081 | input_userauth_info_req(int type, int plen, void *ctxt) | |
1082 | { | |
1083 | Authctxt *authctxt = ctxt; | |
f72e01a5 | 1084 | char *name, *inst, *lang, *prompt, *response; |
1e3b8b07 | 1085 | u_int num_prompts, i; |
94ec8c6b | 1086 | int echo = 0; |
1087 | ||
1088 | debug2("input_userauth_info_req"); | |
1089 | ||
1090 | if (authctxt == NULL) | |
1091 | fatal("input_userauth_info_req: no authentication context"); | |
1092 | ||
1093 | name = packet_get_string(NULL); | |
1094 | inst = packet_get_string(NULL); | |
1095 | lang = packet_get_string(NULL); | |
94ec8c6b | 1096 | if (strlen(name) > 0) |
1097 | cli_mesg(name); | |
94ec8c6b | 1098 | if (strlen(inst) > 0) |
1099 | cli_mesg(inst); | |
f72e01a5 | 1100 | xfree(name); |
94ec8c6b | 1101 | xfree(inst); |
f72e01a5 | 1102 | xfree(lang); |
94ec8c6b | 1103 | |
1104 | num_prompts = packet_get_int(); | |
1105 | /* | |
1106 | * Begin to build info response packet based on prompts requested. | |
1107 | * We commit to providing the correct number of responses, so if | |
1108 | * further on we run into a problem that prevents this, we have to | |
1109 | * be sure and clean this up and send a correct error response. | |
1110 | */ | |
1111 | packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE); | |
1112 | packet_put_int(num_prompts); | |
1113 | ||
1114 | for (i = 0; i < num_prompts; i++) { | |
1115 | prompt = packet_get_string(NULL); | |
1116 | echo = packet_get_char(); | |
1117 | ||
1118 | response = cli_prompt(prompt, echo); | |
1119 | ||
a6215e53 | 1120 | packet_put_cstring(response); |
94ec8c6b | 1121 | memset(response, 0, strlen(response)); |
1122 | xfree(response); | |
1123 | xfree(prompt); | |
1124 | } | |
1125 | packet_done(); /* done with parsing incoming message. */ | |
1126 | ||
a6215e53 | 1127 | packet_inject_ignore(64); |
94ec8c6b | 1128 | packet_send(); |
94ec8c6b | 1129 | } |
a306f2dd | 1130 | |
188adeb2 | 1131 | /* find auth method */ |
1132 | ||
188adeb2 | 1133 | /* |
1134 | * given auth method name, if configurable options permit this method fill | |
1135 | * in auth_ident field and return true, otherwise return false. | |
1136 | */ | |
1137 | int | |
1138 | authmethod_is_enabled(Authmethod *method) | |
1139 | { | |
1140 | if (method == NULL) | |
1141 | return 0; | |
1142 | /* return false if options indicate this method is disabled */ | |
1143 | if (method->enabled == NULL || *method->enabled == 0) | |
1144 | return 0; | |
1145 | /* return false if batch mode is enabled but method needs interactive mode */ | |
1146 | if (method->batch_flag != NULL && *method->batch_flag != 0) | |
1147 | return 0; | |
1148 | return 1; | |
1149 | } | |
a306f2dd | 1150 | |
188adeb2 | 1151 | Authmethod * |
1152 | authmethod_lookup(const char *name) | |
1153 | { | |
1154 | Authmethod *method = NULL; | |
1155 | if (name != NULL) | |
1156 | for (method = authmethods; method->name != NULL; method++) | |
1157 | if (strcmp(name, method->name) == 0) | |
1158 | return method; | |
1159 | debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); | |
1160 | return NULL; | |
1161 | } | |
1162 | ||
cab80f75 | 1163 | /* XXX internal state */ |
1164 | static Authmethod *current = NULL; | |
1165 | static char *supported = NULL; | |
1166 | static char *preferred = NULL; | |
188adeb2 | 1167 | /* |
1168 | * Given the authentication method list sent by the server, return the | |
1169 | * next method we should try. If the server initially sends a nil list, | |
cab80f75 | 1170 | * use a built-in default list. |
2b87da3b | 1171 | */ |
188adeb2 | 1172 | Authmethod * |
1173 | authmethod_get(char *authlist) | |
1174 | { | |
cab80f75 | 1175 | |
1176 | char *name = NULL; | |
1177 | int next; | |
2b87da3b | 1178 | |
188adeb2 | 1179 | /* Use a suitable default if we're passed a nil list. */ |
1180 | if (authlist == NULL || strlen(authlist) == 0) | |
cab80f75 | 1181 | authlist = options.preferred_authentications; |
1182 | ||
1183 | if (supported == NULL || strcmp(authlist, supported) != 0) { | |
1184 | debug3("start over, passed a different list %s", authlist); | |
1185 | if (supported != NULL) | |
1186 | xfree(supported); | |
1187 | supported = xstrdup(authlist); | |
1188 | preferred = options.preferred_authentications; | |
1189 | debug3("preferred %s", preferred); | |
1190 | current = NULL; | |
1191 | } else if (current != NULL && authmethod_is_enabled(current)) | |
1192 | return current; | |
188adeb2 | 1193 | |
cab80f75 | 1194 | for (;;) { |
1195 | if ((name = match_list(preferred, supported, &next)) == NULL) { | |
1196 | debug("no more auth methods to try"); | |
1197 | current = NULL; | |
1198 | return NULL; | |
1199 | } | |
1200 | preferred += next; | |
94ec8c6b | 1201 | debug3("authmethod_lookup %s", name); |
cab80f75 | 1202 | debug3("remaining preferred: %s", preferred); |
1203 | if ((current = authmethod_lookup(name)) != NULL && | |
1204 | authmethod_is_enabled(current)) { | |
94ec8c6b | 1205 | debug3("authmethod_is_enabled %s", name); |
cab80f75 | 1206 | debug("next auth method to try is %s", name); |
1207 | return current; | |
94ec8c6b | 1208 | } |
a306f2dd | 1209 | } |
cab80f75 | 1210 | } |
a22aff1f | 1211 | |
a22aff1f | 1212 | |
cab80f75 | 1213 | #define DELIM "," |
1214 | char * | |
1215 | authmethods_get(void) | |
1216 | { | |
1217 | Authmethod *method = NULL; | |
1218 | char buf[1024]; | |
1219 | ||
1220 | buf[0] = '\0'; | |
1221 | for (method = authmethods; method->name != NULL; method++) { | |
1222 | if (authmethod_is_enabled(method)) { | |
1223 | if (buf[0] != '\0') | |
1224 | strlcat(buf, DELIM, sizeof buf); | |
1225 | strlcat(buf, method->name, sizeof buf); | |
1226 | } | |
1227 | } | |
1228 | return xstrdup(buf); | |
a306f2dd | 1229 | } |