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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" | |
22138a36 | 26 | RCSID("$OpenBSD: sshconnect2.c,v 1.54 2001/03/12 22:02:02 markus 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" |
188adeb2 | 49 | #include "dispatch.h" |
2e73a022 | 50 | #include "authfd.h" |
42f11eb2 | 51 | #include "log.h" |
52 | #include "readconf.h" | |
53 | #include "readpass.h" | |
cab80f75 | 54 | #include "match.h" |
a306f2dd | 55 | |
94ec8c6b | 56 | void ssh_dh1_client(Kex *, char *, struct sockaddr *, Buffer *, Buffer *); |
57 | void ssh_dhgex_client(Kex *, char *, struct sockaddr *, Buffer *, Buffer *); | |
58 | ||
a306f2dd | 59 | /* import */ |
60 | extern char *client_version_string; | |
61 | extern char *server_version_string; | |
62 | extern Options options; | |
63 | ||
64 | /* | |
65 | * SSH2 key exchange | |
66 | */ | |
67 | ||
1e3b8b07 | 68 | u_char *session_id2 = NULL; |
a306f2dd | 69 | int session_id2_len = 0; |
70 | ||
71 | void | |
94ec8c6b | 72 | ssh_kex2(char *host, struct sockaddr *hostaddr) |
73 | { | |
74 | int i, plen; | |
75 | Kex *kex; | |
76 | Buffer *client_kexinit, *server_kexinit; | |
77 | char *sprop[PROPOSAL_MAX]; | |
78 | ||
c523303b | 79 | if (options.ciphers == (char *)-1) { |
80 | log("No valid ciphers for protocol version 2 given, using defaults."); | |
81 | options.ciphers = NULL; | |
94ec8c6b | 82 | } |
83 | if (options.ciphers != NULL) { | |
84 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = | |
85 | myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; | |
86 | } | |
87 | if (options.compression) { | |
b2552997 | 88 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = |
94ec8c6b | 89 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib"; |
90 | } else { | |
b2552997 | 91 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = |
94ec8c6b | 92 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none"; |
93 | } | |
b2552997 | 94 | if (options.macs != NULL) { |
95 | myproposal[PROPOSAL_MAC_ALGS_CTOS] = | |
96 | myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; | |
97 | } | |
94ec8c6b | 98 | |
99 | /* buffers with raw kexinit messages */ | |
100 | server_kexinit = xmalloc(sizeof(*server_kexinit)); | |
101 | buffer_init(server_kexinit); | |
102 | client_kexinit = kex_init(myproposal); | |
103 | ||
104 | /* algorithm negotiation */ | |
105 | kex_exchange_kexinit(client_kexinit, server_kexinit, sprop); | |
106 | kex = kex_choose_conf(myproposal, sprop, 0); | |
107 | for (i = 0; i < PROPOSAL_MAX; i++) | |
108 | xfree(sprop[i]); | |
109 | ||
110 | /* server authentication and session key agreement */ | |
111 | switch(kex->kex_type) { | |
112 | case DH_GRP1_SHA1: | |
113 | ssh_dh1_client(kex, host, hostaddr, | |
114 | client_kexinit, server_kexinit); | |
115 | break; | |
116 | case DH_GEX_SHA1: | |
117 | ssh_dhgex_client(kex, host, hostaddr, client_kexinit, | |
118 | server_kexinit); | |
119 | break; | |
120 | default: | |
121 | fatal("Unsupported key exchange %d", kex->kex_type); | |
122 | } | |
123 | ||
124 | buffer_free(client_kexinit); | |
125 | buffer_free(server_kexinit); | |
126 | xfree(client_kexinit); | |
127 | xfree(server_kexinit); | |
128 | ||
129 | debug("Wait SSH2_MSG_NEWKEYS."); | |
130 | packet_read_expect(&plen, SSH2_MSG_NEWKEYS); | |
131 | packet_done(); | |
132 | debug("GOT SSH2_MSG_NEWKEYS."); | |
133 | ||
134 | debug("send SSH2_MSG_NEWKEYS."); | |
135 | packet_start(SSH2_MSG_NEWKEYS); | |
136 | packet_send(); | |
137 | packet_write_wait(); | |
138 | debug("done: send SSH2_MSG_NEWKEYS."); | |
139 | ||
140 | #ifdef DEBUG_KEXDH | |
141 | /* send 1st encrypted/maced/compressed message */ | |
142 | packet_start(SSH2_MSG_IGNORE); | |
143 | packet_put_cstring("markus"); | |
144 | packet_send(); | |
145 | packet_write_wait(); | |
146 | #endif | |
147 | debug("done: KEX2."); | |
148 | } | |
149 | ||
150 | /* diffie-hellman-group1-sha1 */ | |
151 | ||
152 | void | |
2b87da3b | 153 | ssh_dh1_client(Kex *kex, char *host, struct sockaddr *hostaddr, |
94ec8c6b | 154 | Buffer *client_kexinit, Buffer *server_kexinit) |
a306f2dd | 155 | { |
188adeb2 | 156 | #ifdef DEBUG_KEXDH |
157 | int i; | |
158 | #endif | |
71276795 | 159 | int plen, dlen; |
1e3b8b07 | 160 | u_int klen, kout; |
a306f2dd | 161 | char *signature = NULL; |
1e3b8b07 | 162 | u_int slen; |
a306f2dd | 163 | char *server_host_key_blob = NULL; |
164 | Key *server_host_key; | |
1e3b8b07 | 165 | u_int sbloblen; |
a306f2dd | 166 | DH *dh; |
167 | BIGNUM *dh_server_pub = 0; | |
168 | BIGNUM *shared_secret = 0; | |
1e3b8b07 | 169 | u_char *kbuf; |
170 | u_char *hash; | |
a306f2dd | 171 | |
a306f2dd | 172 | debug("Sending SSH2_MSG_KEXDH_INIT."); |
a306f2dd | 173 | /* generate and send 'e', client DH public key */ |
174 | dh = dh_new_group1(); | |
7de5b06b | 175 | dh_gen_key(dh, kex->we_need * 8); |
a306f2dd | 176 | packet_start(SSH2_MSG_KEXDH_INIT); |
177 | packet_put_bignum2(dh->pub_key); | |
178 | packet_send(); | |
179 | packet_write_wait(); | |
180 | ||
181 | #ifdef DEBUG_KEXDH | |
182 | fprintf(stderr, "\np= "); | |
188adeb2 | 183 | BN_print_fp(stderr, dh->p); |
a306f2dd | 184 | fprintf(stderr, "\ng= "); |
188adeb2 | 185 | BN_print_fp(stderr, dh->g); |
a306f2dd | 186 | fprintf(stderr, "\npub= "); |
188adeb2 | 187 | BN_print_fp(stderr, dh->pub_key); |
a306f2dd | 188 | fprintf(stderr, "\n"); |
189 | DHparams_print_fp(stderr, dh); | |
190 | #endif | |
191 | ||
192 | debug("Wait SSH2_MSG_KEXDH_REPLY."); | |
193 | ||
71276795 | 194 | packet_read_expect(&plen, SSH2_MSG_KEXDH_REPLY); |
a306f2dd | 195 | |
196 | debug("Got SSH2_MSG_KEXDH_REPLY."); | |
197 | ||
198 | /* key, cert */ | |
199 | server_host_key_blob = packet_get_string(&sbloblen); | |
fa08c86b | 200 | server_host_key = key_from_blob(server_host_key_blob, sbloblen); |
a306f2dd | 201 | if (server_host_key == NULL) |
202 | fatal("cannot decode server_host_key_blob"); | |
203 | ||
204 | check_host_key(host, hostaddr, server_host_key, | |
94ec8c6b | 205 | options.user_hostfile2, options.system_hostfile2); |
a306f2dd | 206 | |
207 | /* DH paramter f, server public DH key */ | |
208 | dh_server_pub = BN_new(); | |
209 | if (dh_server_pub == NULL) | |
210 | fatal("dh_server_pub == NULL"); | |
211 | packet_get_bignum2(dh_server_pub, &dlen); | |
212 | ||
213 | #ifdef DEBUG_KEXDH | |
214 | fprintf(stderr, "\ndh_server_pub= "); | |
188adeb2 | 215 | BN_print_fp(stderr, dh_server_pub); |
a306f2dd | 216 | fprintf(stderr, "\n"); |
217 | debug("bits %d", BN_num_bits(dh_server_pub)); | |
218 | #endif | |
219 | ||
220 | /* signed H */ | |
221 | signature = packet_get_string(&slen); | |
222 | packet_done(); | |
223 | ||
224 | if (!dh_pub_is_valid(dh, dh_server_pub)) | |
225 | packet_disconnect("bad server public DH value"); | |
226 | ||
227 | klen = DH_size(dh); | |
228 | kbuf = xmalloc(klen); | |
229 | kout = DH_compute_key(kbuf, dh_server_pub, dh); | |
230 | #ifdef DEBUG_KEXDH | |
231 | debug("shared secret: len %d/%d", klen, kout); | |
232 | fprintf(stderr, "shared secret == "); | |
233 | for (i = 0; i< kout; i++) | |
234 | fprintf(stderr, "%02x", (kbuf[i])&0xff); | |
235 | fprintf(stderr, "\n"); | |
236 | #endif | |
237 | shared_secret = BN_new(); | |
238 | ||
239 | BN_bin2bn(kbuf, kout, shared_secret); | |
240 | memset(kbuf, 0, klen); | |
241 | xfree(kbuf); | |
242 | ||
243 | /* calc and verify H */ | |
244 | hash = kex_hash( | |
245 | client_version_string, | |
246 | server_version_string, | |
247 | buffer_ptr(client_kexinit), buffer_len(client_kexinit), | |
248 | buffer_ptr(server_kexinit), buffer_len(server_kexinit), | |
249 | server_host_key_blob, sbloblen, | |
250 | dh->pub_key, | |
251 | dh_server_pub, | |
252 | shared_secret | |
253 | ); | |
254 | xfree(server_host_key_blob); | |
71276795 | 255 | DH_free(dh); |
53a24016 | 256 | BN_free(dh_server_pub); |
a306f2dd | 257 | #ifdef DEBUG_KEXDH |
258 | fprintf(stderr, "hash == "); | |
259 | for (i = 0; i< 20; i++) | |
260 | fprintf(stderr, "%02x", (hash[i])&0xff); | |
261 | fprintf(stderr, "\n"); | |
262 | #endif | |
1e3b8b07 | 263 | if (key_verify(server_host_key, (u_char *)signature, slen, hash, 20) != 1) |
fa08c86b | 264 | fatal("key_verify failed for server_host_key"); |
a306f2dd | 265 | key_free(server_host_key); |
53a24016 | 266 | xfree(signature); |
a306f2dd | 267 | |
268 | kex_derive_keys(kex, hash, shared_secret); | |
53a24016 | 269 | BN_clear_free(shared_secret); |
a306f2dd | 270 | packet_set_kex(kex); |
271 | ||
a306f2dd | 272 | /* save session id */ |
273 | session_id2_len = 20; | |
274 | session_id2 = xmalloc(session_id2_len); | |
275 | memcpy(session_id2, hash, session_id2_len); | |
71276795 | 276 | } |
277 | ||
94ec8c6b | 278 | /* diffie-hellman-group-exchange-sha1 */ |
279 | ||
280 | /* | |
281 | * Estimates the group order for a Diffie-Hellman group that has an | |
282 | * attack complexity approximately the same as O(2**bits). Estimate | |
283 | * with: O(exp(1.9223 * (ln q)^(1/3) (ln ln q)^(2/3))) | |
284 | */ | |
285 | ||
286 | int | |
287 | dh_estimate(int bits) | |
288 | { | |
2b87da3b | 289 | |
94ec8c6b | 290 | if (bits < 64) |
291 | return (512); /* O(2**63) */ | |
292 | if (bits < 128) | |
293 | return (1024); /* O(2**86) */ | |
294 | if (bits < 192) | |
295 | return (2048); /* O(2**116) */ | |
296 | return (4096); /* O(2**156) */ | |
297 | } | |
298 | ||
71276795 | 299 | void |
94ec8c6b | 300 | ssh_dhgex_client(Kex *kex, char *host, struct sockaddr *hostaddr, |
301 | Buffer *client_kexinit, Buffer *server_kexinit) | |
71276795 | 302 | { |
94ec8c6b | 303 | #ifdef DEBUG_KEXDH |
304 | int i; | |
305 | #endif | |
306 | int plen, dlen; | |
1e3b8b07 | 307 | u_int klen, kout; |
94ec8c6b | 308 | char *signature = NULL; |
1e3b8b07 | 309 | u_int slen, nbits; |
94ec8c6b | 310 | char *server_host_key_blob = NULL; |
311 | Key *server_host_key; | |
1e3b8b07 | 312 | u_int sbloblen; |
94ec8c6b | 313 | DH *dh; |
314 | BIGNUM *dh_server_pub = 0; | |
315 | BIGNUM *shared_secret = 0; | |
316 | BIGNUM *p = 0, *g = 0; | |
1e3b8b07 | 317 | u_char *kbuf; |
318 | u_char *hash; | |
71276795 | 319 | |
7de5b06b | 320 | nbits = dh_estimate(kex->we_need * 8); |
71276795 | 321 | |
94ec8c6b | 322 | debug("Sending SSH2_MSG_KEX_DH_GEX_REQUEST."); |
323 | packet_start(SSH2_MSG_KEX_DH_GEX_REQUEST); | |
324 | packet_put_int(nbits); | |
325 | packet_send(); | |
326 | packet_write_wait(); | |
71276795 | 327 | |
94ec8c6b | 328 | #ifdef DEBUG_KEXDH |
329 | fprintf(stderr, "\nnbits = %d", nbits); | |
330 | #endif | |
71276795 | 331 | |
94ec8c6b | 332 | debug("Wait SSH2_MSG_KEX_DH_GEX_GROUP."); |
71276795 | 333 | |
94ec8c6b | 334 | packet_read_expect(&plen, SSH2_MSG_KEX_DH_GEX_GROUP); |
a306f2dd | 335 | |
94ec8c6b | 336 | debug("Got SSH2_MSG_KEX_DH_GEX_GROUP."); |
a306f2dd | 337 | |
94ec8c6b | 338 | if ((p = BN_new()) == NULL) |
339 | fatal("BN_new"); | |
340 | packet_get_bignum2(p, &dlen); | |
341 | if ((g = BN_new()) == NULL) | |
342 | fatal("BN_new"); | |
343 | packet_get_bignum2(g, &dlen); | |
42f11eb2 | 344 | dh = dh_new_group(g, p); |
a306f2dd | 345 | |
7de5b06b | 346 | dh_gen_key(dh, kex->we_need * 8); |
3e1caa83 | 347 | |
a306f2dd | 348 | #ifdef DEBUG_KEXDH |
94ec8c6b | 349 | fprintf(stderr, "\np= "); |
350 | BN_print_fp(stderr, dh->p); | |
351 | fprintf(stderr, "\ng= "); | |
352 | BN_print_fp(stderr, dh->g); | |
353 | fprintf(stderr, "\npub= "); | |
354 | BN_print_fp(stderr, dh->pub_key); | |
355 | fprintf(stderr, "\n"); | |
356 | DHparams_print_fp(stderr, dh); | |
357 | #endif | |
358 | ||
359 | debug("Sending SSH2_MSG_KEX_DH_GEX_INIT."); | |
360 | /* generate and send 'e', client DH public key */ | |
361 | packet_start(SSH2_MSG_KEX_DH_GEX_INIT); | |
362 | packet_put_bignum2(dh->pub_key); | |
a306f2dd | 363 | packet_send(); |
364 | packet_write_wait(); | |
94ec8c6b | 365 | |
366 | debug("Wait SSH2_MSG_KEX_DH_GEX_REPLY."); | |
367 | ||
368 | packet_read_expect(&plen, SSH2_MSG_KEX_DH_GEX_REPLY); | |
369 | ||
370 | debug("Got SSH2_MSG_KEXDH_REPLY."); | |
371 | ||
372 | /* key, cert */ | |
373 | server_host_key_blob = packet_get_string(&sbloblen); | |
fa08c86b | 374 | server_host_key = key_from_blob(server_host_key_blob, sbloblen); |
94ec8c6b | 375 | if (server_host_key == NULL) |
376 | fatal("cannot decode server_host_key_blob"); | |
377 | ||
378 | check_host_key(host, hostaddr, server_host_key, | |
379 | options.user_hostfile2, options.system_hostfile2); | |
380 | ||
381 | /* DH paramter f, server public DH key */ | |
382 | dh_server_pub = BN_new(); | |
383 | if (dh_server_pub == NULL) | |
384 | fatal("dh_server_pub == NULL"); | |
385 | packet_get_bignum2(dh_server_pub, &dlen); | |
386 | ||
387 | #ifdef DEBUG_KEXDH | |
388 | fprintf(stderr, "\ndh_server_pub= "); | |
389 | BN_print_fp(stderr, dh_server_pub); | |
390 | fprintf(stderr, "\n"); | |
391 | debug("bits %d", BN_num_bits(dh_server_pub)); | |
a306f2dd | 392 | #endif |
94ec8c6b | 393 | |
394 | /* signed H */ | |
395 | signature = packet_get_string(&slen); | |
396 | packet_done(); | |
397 | ||
398 | if (!dh_pub_is_valid(dh, dh_server_pub)) | |
399 | packet_disconnect("bad server public DH value"); | |
400 | ||
401 | klen = DH_size(dh); | |
402 | kbuf = xmalloc(klen); | |
403 | kout = DH_compute_key(kbuf, dh_server_pub, dh); | |
404 | #ifdef DEBUG_KEXDH | |
405 | debug("shared secret: len %d/%d", klen, kout); | |
406 | fprintf(stderr, "shared secret == "); | |
407 | for (i = 0; i< kout; i++) | |
408 | fprintf(stderr, "%02x", (kbuf[i])&0xff); | |
409 | fprintf(stderr, "\n"); | |
410 | #endif | |
411 | shared_secret = BN_new(); | |
412 | ||
413 | BN_bin2bn(kbuf, kout, shared_secret); | |
414 | memset(kbuf, 0, klen); | |
415 | xfree(kbuf); | |
416 | ||
417 | /* calc and verify H */ | |
418 | hash = kex_hash_gex( | |
419 | client_version_string, | |
420 | server_version_string, | |
421 | buffer_ptr(client_kexinit), buffer_len(client_kexinit), | |
422 | buffer_ptr(server_kexinit), buffer_len(server_kexinit), | |
423 | server_host_key_blob, sbloblen, | |
2b87da3b | 424 | nbits, dh->p, dh->g, |
94ec8c6b | 425 | dh->pub_key, |
426 | dh_server_pub, | |
427 | shared_secret | |
428 | ); | |
429 | xfree(server_host_key_blob); | |
430 | DH_free(dh); | |
53a24016 | 431 | BN_free(dh_server_pub); |
94ec8c6b | 432 | #ifdef DEBUG_KEXDH |
433 | fprintf(stderr, "hash == "); | |
434 | for (i = 0; i< 20; i++) | |
435 | fprintf(stderr, "%02x", (hash[i])&0xff); | |
436 | fprintf(stderr, "\n"); | |
437 | #endif | |
1e3b8b07 | 438 | if (key_verify(server_host_key, (u_char *)signature, slen, hash, 20) != 1) |
fa08c86b | 439 | fatal("key_verify failed for server_host_key"); |
94ec8c6b | 440 | key_free(server_host_key); |
53a24016 | 441 | xfree(signature); |
94ec8c6b | 442 | |
443 | kex_derive_keys(kex, hash, shared_secret); | |
53a24016 | 444 | BN_clear_free(shared_secret); |
94ec8c6b | 445 | packet_set_kex(kex); |
446 | ||
447 | /* save session id */ | |
448 | session_id2_len = 20; | |
449 | session_id2 = xmalloc(session_id2_len); | |
450 | memcpy(session_id2, hash, session_id2_len); | |
a306f2dd | 451 | } |
71276795 | 452 | |
a306f2dd | 453 | /* |
454 | * Authenticate user | |
455 | */ | |
188adeb2 | 456 | |
457 | typedef struct Authctxt Authctxt; | |
458 | typedef struct Authmethod Authmethod; | |
459 | ||
460 | typedef int sign_cb_fn( | |
461 | Authctxt *authctxt, Key *key, | |
1e3b8b07 | 462 | u_char **sigp, int *lenp, u_char *data, int datalen); |
188adeb2 | 463 | |
464 | struct Authctxt { | |
465 | const char *server_user; | |
466 | const char *host; | |
467 | const char *service; | |
468 | AuthenticationConnection *agent; | |
188adeb2 | 469 | Authmethod *method; |
94ec8c6b | 470 | int success; |
fee56204 | 471 | char *authlist; |
472 | Key *last_key; | |
473 | sign_cb_fn *last_key_sign; | |
474 | int last_key_hint; | |
188adeb2 | 475 | }; |
476 | struct Authmethod { | |
477 | char *name; /* string to compare against server's list */ | |
478 | int (*userauth)(Authctxt *authctxt); | |
479 | int *enabled; /* flag in option struct that enables method */ | |
480 | int *batch_flag; /* flag in option struct that disables method */ | |
481 | }; | |
482 | ||
483 | void input_userauth_success(int type, int plen, void *ctxt); | |
484 | void input_userauth_failure(int type, int plen, void *ctxt); | |
9616313f | 485 | void input_userauth_banner(int type, int plen, void *ctxt); |
188adeb2 | 486 | void input_userauth_error(int type, int plen, void *ctxt); |
94ec8c6b | 487 | void input_userauth_info_req(int type, int plen, void *ctxt); |
fee56204 | 488 | void input_userauth_pk_ok(int type, int plen, void *ctxt); |
94ec8c6b | 489 | |
490 | int userauth_none(Authctxt *authctxt); | |
188adeb2 | 491 | int userauth_pubkey(Authctxt *authctxt); |
492 | int userauth_passwd(Authctxt *authctxt); | |
94ec8c6b | 493 | int userauth_kbdint(Authctxt *authctxt); |
188adeb2 | 494 | |
fee56204 | 495 | void userauth(Authctxt *authctxt, char *authlist); |
496 | ||
497 | int | |
498 | sign_and_send_pubkey(Authctxt *authctxt, Key *k, | |
499 | sign_cb_fn *sign_callback); | |
500 | void clear_auth_state(Authctxt *authctxt); | |
501 | ||
94ec8c6b | 502 | Authmethod *authmethod_get(char *authlist); |
503 | Authmethod *authmethod_lookup(const char *name); | |
cab80f75 | 504 | char *authmethods_get(void); |
188adeb2 | 505 | |
506 | Authmethod authmethods[] = { | |
507 | {"publickey", | |
508 | userauth_pubkey, | |
fa08c86b | 509 | &options.pubkey_authentication, |
188adeb2 | 510 | NULL}, |
511 | {"password", | |
512 | userauth_passwd, | |
513 | &options.password_authentication, | |
514 | &options.batch_mode}, | |
94ec8c6b | 515 | {"keyboard-interactive", |
516 | userauth_kbdint, | |
517 | &options.kbd_interactive_authentication, | |
518 | &options.batch_mode}, | |
519 | {"none", | |
520 | userauth_none, | |
521 | NULL, | |
522 | NULL}, | |
188adeb2 | 523 | {NULL, NULL, NULL, NULL} |
524 | }; | |
525 | ||
526 | void | |
527 | ssh_userauth2(const char *server_user, char *host) | |
528 | { | |
529 | Authctxt authctxt; | |
530 | int type; | |
531 | int plen; | |
532 | ||
d464095c | 533 | if (options.challenge_reponse_authentication) |
534 | options.kbd_interactive_authentication = 1; | |
535 | ||
188adeb2 | 536 | debug("send SSH2_MSG_SERVICE_REQUEST"); |
537 | packet_start(SSH2_MSG_SERVICE_REQUEST); | |
538 | packet_put_cstring("ssh-userauth"); | |
539 | packet_send(); | |
540 | packet_write_wait(); | |
541 | type = packet_read(&plen); | |
542 | if (type != SSH2_MSG_SERVICE_ACCEPT) { | |
543 | fatal("denied SSH2_MSG_SERVICE_ACCEPT: %d", type); | |
544 | } | |
545 | if (packet_remaining() > 0) { | |
546 | char *reply = packet_get_string(&plen); | |
547 | debug("service_accept: %s", reply); | |
548 | xfree(reply); | |
188adeb2 | 549 | } else { |
550 | debug("buggy server: service_accept w/o service"); | |
551 | } | |
552 | packet_done(); | |
553 | debug("got SSH2_MSG_SERVICE_ACCEPT"); | |
554 | ||
cab80f75 | 555 | if (options.preferred_authentications == NULL) |
556 | options.preferred_authentications = authmethods_get(); | |
557 | ||
188adeb2 | 558 | /* setup authentication context */ |
559 | authctxt.agent = ssh_get_authentication_connection(); | |
560 | authctxt.server_user = server_user; | |
561 | authctxt.host = host; | |
562 | authctxt.service = "ssh-connection"; /* service name */ | |
563 | authctxt.success = 0; | |
94ec8c6b | 564 | authctxt.method = authmethod_lookup("none"); |
fee56204 | 565 | authctxt.authlist = NULL; |
94ec8c6b | 566 | if (authctxt.method == NULL) |
567 | fatal("ssh_userauth2: internal error: cannot send userauth none request"); | |
188adeb2 | 568 | |
569 | /* initial userauth request */ | |
94ec8c6b | 570 | userauth_none(&authctxt); |
188adeb2 | 571 | |
572 | dispatch_init(&input_userauth_error); | |
573 | dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); | |
574 | dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure); | |
9616313f | 575 | dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner); |
188adeb2 | 576 | dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */ |
577 | ||
578 | if (authctxt.agent != NULL) | |
579 | ssh_close_authentication_connection(authctxt.agent); | |
580 | ||
8abcdba4 | 581 | debug("ssh-userauth2 successful: method %s", authctxt.method->name); |
188adeb2 | 582 | } |
583 | void | |
fee56204 | 584 | userauth(Authctxt *authctxt, char *authlist) |
585 | { | |
586 | if (authlist == NULL) { | |
587 | authlist = authctxt->authlist; | |
588 | } else { | |
589 | if (authctxt->authlist) | |
590 | xfree(authctxt->authlist); | |
591 | authctxt->authlist = authlist; | |
592 | } | |
593 | for (;;) { | |
594 | Authmethod *method = authmethod_get(authlist); | |
595 | if (method == NULL) | |
596 | fatal("Permission denied (%s).", authlist); | |
597 | authctxt->method = method; | |
598 | if (method->userauth(authctxt) != 0) { | |
599 | debug2("we sent a %s packet, wait for reply", method->name); | |
600 | break; | |
601 | } else { | |
602 | debug2("we did not send a packet, disable method"); | |
603 | method->enabled = NULL; | |
604 | } | |
605 | } | |
606 | } | |
607 | void | |
188adeb2 | 608 | input_userauth_error(int type, int plen, void *ctxt) |
609 | { | |
9616313f | 610 | fatal("input_userauth_error: bad message during authentication: " |
611 | "type %d", type); | |
612 | } | |
613 | void | |
614 | input_userauth_banner(int type, int plen, void *ctxt) | |
615 | { | |
616 | char *msg, *lang; | |
617 | debug3("input_userauth_banner"); | |
618 | msg = packet_get_string(NULL); | |
619 | lang = packet_get_string(NULL); | |
620 | fprintf(stderr, "%s", msg); | |
621 | xfree(msg); | |
622 | xfree(lang); | |
188adeb2 | 623 | } |
624 | void | |
625 | input_userauth_success(int type, int plen, void *ctxt) | |
626 | { | |
627 | Authctxt *authctxt = ctxt; | |
628 | if (authctxt == NULL) | |
629 | fatal("input_userauth_success: no authentication context"); | |
fee56204 | 630 | if (authctxt->authlist) |
631 | xfree(authctxt->authlist); | |
632 | clear_auth_state(authctxt); | |
188adeb2 | 633 | authctxt->success = 1; /* break out */ |
634 | } | |
635 | void | |
636 | input_userauth_failure(int type, int plen, void *ctxt) | |
637 | { | |
188adeb2 | 638 | Authctxt *authctxt = ctxt; |
639 | char *authlist = NULL; | |
640 | int partial; | |
188adeb2 | 641 | |
642 | if (authctxt == NULL) | |
643 | fatal("input_userauth_failure: no authentication context"); | |
644 | ||
94ec8c6b | 645 | authlist = packet_get_string(NULL); |
188adeb2 | 646 | partial = packet_get_char(); |
647 | packet_done(); | |
648 | ||
649 | if (partial != 0) | |
f72e01a5 | 650 | log("Authenticated with partial success."); |
188adeb2 | 651 | debug("authentications that can continue: %s", authlist); |
652 | ||
fee56204 | 653 | clear_auth_state(authctxt); |
654 | userauth(authctxt, authlist); | |
655 | } | |
656 | void | |
657 | input_userauth_pk_ok(int type, int plen, void *ctxt) | |
658 | { | |
659 | Authctxt *authctxt = ctxt; | |
660 | Key *key = NULL; | |
661 | Buffer b; | |
662 | int alen, blen, pktype, sent = 0; | |
22138a36 | 663 | char *pkalg, *pkblob, *fp; |
fee56204 | 664 | |
665 | if (authctxt == NULL) | |
666 | fatal("input_userauth_pk_ok: no authentication context"); | |
667 | if (datafellows & SSH_BUG_PKOK) { | |
668 | /* this is similar to SSH_BUG_PKAUTH */ | |
669 | debug2("input_userauth_pk_ok: SSH_BUG_PKOK"); | |
670 | pkblob = packet_get_string(&blen); | |
671 | buffer_init(&b); | |
672 | buffer_append(&b, pkblob, blen); | |
673 | pkalg = buffer_get_string(&b, &alen); | |
674 | buffer_free(&b); | |
675 | } else { | |
676 | pkalg = packet_get_string(&alen); | |
677 | pkblob = packet_get_string(&blen); | |
678 | } | |
679 | packet_done(); | |
680 | ||
681 | debug("input_userauth_pk_ok: pkalg %s blen %d lastkey %p hint %d", | |
682 | pkalg, blen, authctxt->last_key, authctxt->last_key_hint); | |
683 | ||
684 | do { | |
685 | if (authctxt->last_key == NULL || | |
686 | authctxt->last_key_sign == NULL) { | |
687 | debug("no last key or no sign cb"); | |
188adeb2 | 688 | break; |
188adeb2 | 689 | } |
fee56204 | 690 | if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) { |
691 | debug("unknown pkalg %s", pkalg); | |
692 | break; | |
693 | } | |
694 | if ((key = key_from_blob(pkblob, blen)) == NULL) { | |
695 | debug("no key from blob. pkalg %s", pkalg); | |
696 | break; | |
697 | } | |
22138a36 | 698 | fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX); |
699 | debug2("input_userauth_pk_ok: fp %s", fp); | |
700 | xfree(fp); | |
fee56204 | 701 | if (!key_equal(key, authctxt->last_key)) { |
702 | debug("key != last_key"); | |
703 | break; | |
704 | } | |
705 | sent = sign_and_send_pubkey(authctxt, key, | |
706 | authctxt->last_key_sign); | |
707 | } while(0); | |
708 | ||
709 | if (key != NULL) | |
710 | key_free(key); | |
711 | xfree(pkalg); | |
712 | xfree(pkblob); | |
713 | ||
714 | /* unregister */ | |
715 | clear_auth_state(authctxt); | |
716 | dispatch_set(SSH2_MSG_USERAUTH_PK_OK, NULL); | |
717 | ||
718 | /* try another method if we did not send a packet*/ | |
719 | if (sent == 0) | |
720 | userauth(authctxt, NULL); | |
721 | ||
188adeb2 | 722 | } |
723 | ||
94ec8c6b | 724 | int |
725 | userauth_none(Authctxt *authctxt) | |
726 | { | |
727 | /* initial userauth request */ | |
728 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
729 | packet_put_cstring(authctxt->server_user); | |
730 | packet_put_cstring(authctxt->service); | |
731 | packet_put_cstring(authctxt->method->name); | |
732 | packet_send(); | |
94ec8c6b | 733 | return 1; |
734 | } | |
735 | ||
a306f2dd | 736 | int |
188adeb2 | 737 | userauth_passwd(Authctxt *authctxt) |
a306f2dd | 738 | { |
1d1ffb87 | 739 | static int attempt = 0; |
a306f2dd | 740 | char prompt[80]; |
741 | char *password; | |
742 | ||
fa649821 | 743 | if (attempt++ >= options.number_of_password_prompts) |
1d1ffb87 | 744 | return 0; |
745 | ||
fa649821 | 746 | if(attempt != 1) |
747 | error("Permission denied, please try again."); | |
748 | ||
f72e01a5 | 749 | snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ", |
188adeb2 | 750 | authctxt->server_user, authctxt->host); |
a306f2dd | 751 | password = read_passphrase(prompt, 0); |
752 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
188adeb2 | 753 | packet_put_cstring(authctxt->server_user); |
754 | packet_put_cstring(authctxt->service); | |
94ec8c6b | 755 | packet_put_cstring(authctxt->method->name); |
a306f2dd | 756 | packet_put_char(0); |
a6215e53 | 757 | packet_put_cstring(password); |
a306f2dd | 758 | memset(password, 0, strlen(password)); |
759 | xfree(password); | |
a6215e53 | 760 | packet_inject_ignore(64); |
a306f2dd | 761 | packet_send(); |
a306f2dd | 762 | return 1; |
763 | } | |
764 | ||
fee56204 | 765 | void |
766 | clear_auth_state(Authctxt *authctxt) | |
767 | { | |
768 | /* XXX clear authentication state */ | |
769 | if (authctxt->last_key != NULL && authctxt->last_key_hint == -1) { | |
770 | debug3("clear_auth_state: key_free %p", authctxt->last_key); | |
771 | key_free(authctxt->last_key); | |
772 | } | |
773 | authctxt->last_key = NULL; | |
774 | authctxt->last_key_hint = -2; | |
775 | authctxt->last_key_sign = NULL; | |
776 | } | |
777 | ||
2e73a022 | 778 | int |
188adeb2 | 779 | sign_and_send_pubkey(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback) |
a306f2dd | 780 | { |
781 | Buffer b; | |
1e3b8b07 | 782 | u_char *blob, *signature; |
a306f2dd | 783 | int bloblen, slen; |
74fc9186 | 784 | int skip = 0; |
2e73a022 | 785 | int ret = -1; |
94ec8c6b | 786 | int have_sig = 1; |
a306f2dd | 787 | |
cbc5abf9 | 788 | debug3("sign_and_send_pubkey"); |
fee56204 | 789 | |
fa08c86b | 790 | if (key_to_blob(k, &blob, &bloblen) == 0) { |
791 | /* we cannot handle this key */ | |
cbc5abf9 | 792 | debug3("sign_and_send_pubkey: cannot handle key"); |
fa08c86b | 793 | return 0; |
794 | } | |
a306f2dd | 795 | /* data to be signed */ |
796 | buffer_init(&b); | |
33de75a3 | 797 | if (datafellows & SSH_OLD_SESSIONID) { |
74fc9186 | 798 | buffer_append(&b, session_id2, session_id2_len); |
2b87da3b | 799 | skip = session_id2_len; |
33de75a3 | 800 | } else { |
801 | buffer_put_string(&b, session_id2, session_id2_len); | |
802 | skip = buffer_len(&b); | |
74fc9186 | 803 | } |
a306f2dd | 804 | buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); |
188adeb2 | 805 | buffer_put_cstring(&b, authctxt->server_user); |
d0c832f3 | 806 | buffer_put_cstring(&b, |
cbc5abf9 | 807 | datafellows & SSH_BUG_PKSERVICE ? |
d0c832f3 | 808 | "ssh-userauth" : |
188adeb2 | 809 | authctxt->service); |
cbc5abf9 | 810 | if (datafellows & SSH_BUG_PKAUTH) { |
811 | buffer_put_char(&b, have_sig); | |
812 | } else { | |
813 | buffer_put_cstring(&b, authctxt->method->name); | |
814 | buffer_put_char(&b, have_sig); | |
2b87da3b | 815 | buffer_put_cstring(&b, key_ssh_name(k)); |
cbc5abf9 | 816 | } |
a306f2dd | 817 | buffer_put_string(&b, blob, bloblen); |
a306f2dd | 818 | |
819 | /* generate signature */ | |
fee56204 | 820 | ret = (*sign_callback)(authctxt, k, &signature, &slen, |
821 | buffer_ptr(&b), buffer_len(&b)); | |
2e73a022 | 822 | if (ret == -1) { |
823 | xfree(blob); | |
824 | buffer_free(&b); | |
825 | return 0; | |
826 | } | |
fa08c86b | 827 | #ifdef DEBUG_PK |
a306f2dd | 828 | buffer_dump(&b); |
829 | #endif | |
cbc5abf9 | 830 | if (datafellows & SSH_BUG_PKSERVICE) { |
d0c832f3 | 831 | buffer_clear(&b); |
832 | buffer_append(&b, session_id2, session_id2_len); | |
fee56204 | 833 | skip = session_id2_len; |
d0c832f3 | 834 | buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); |
188adeb2 | 835 | buffer_put_cstring(&b, authctxt->server_user); |
836 | buffer_put_cstring(&b, authctxt->service); | |
94ec8c6b | 837 | buffer_put_cstring(&b, authctxt->method->name); |
838 | buffer_put_char(&b, have_sig); | |
cbc5abf9 | 839 | if (!(datafellows & SSH_BUG_PKAUTH)) |
2b87da3b | 840 | buffer_put_cstring(&b, key_ssh_name(k)); |
d0c832f3 | 841 | buffer_put_string(&b, blob, bloblen); |
842 | } | |
843 | xfree(blob); | |
fee56204 | 844 | |
a306f2dd | 845 | /* append signature */ |
846 | buffer_put_string(&b, signature, slen); | |
847 | xfree(signature); | |
848 | ||
849 | /* skip session id and packet type */ | |
74fc9186 | 850 | if (buffer_len(&b) < skip + 1) |
188adeb2 | 851 | fatal("userauth_pubkey: internal error"); |
74fc9186 | 852 | buffer_consume(&b, skip + 1); |
a306f2dd | 853 | |
854 | /* put remaining data from buffer into packet */ | |
855 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
856 | packet_put_raw(buffer_ptr(&b), buffer_len(&b)); | |
857 | buffer_free(&b); | |
a306f2dd | 858 | packet_send(); |
2e73a022 | 859 | |
860 | return 1; | |
4c8722d9 | 861 | } |
862 | ||
863 | int | |
fee56204 | 864 | send_pubkey_test(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback, |
865 | int hint) | |
4c8722d9 | 866 | { |
fee56204 | 867 | u_char *blob; |
868 | int bloblen, have_sig = 0; | |
4c8722d9 | 869 | |
fee56204 | 870 | debug3("send_pubkey_test"); |
871 | ||
872 | if (key_to_blob(k, &blob, &bloblen) == 0) { | |
873 | /* we cannot handle this key */ | |
874 | debug3("send_pubkey_test: cannot handle key"); | |
4c8722d9 | 875 | return 0; |
876 | } | |
fee56204 | 877 | /* register callback for USERAUTH_PK_OK message */ |
878 | authctxt->last_key_sign = sign_callback; | |
879 | authctxt->last_key_hint = hint; | |
880 | authctxt->last_key = k; | |
881 | dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok); | |
4c8722d9 | 882 | |
fee56204 | 883 | packet_start(SSH2_MSG_USERAUTH_REQUEST); |
884 | packet_put_cstring(authctxt->server_user); | |
885 | packet_put_cstring(authctxt->service); | |
886 | packet_put_cstring(authctxt->method->name); | |
887 | packet_put_char(have_sig); | |
888 | if (!(datafellows & SSH_BUG_PKAUTH)) | |
889 | packet_put_cstring(key_ssh_name(k)); | |
890 | packet_put_string(blob, bloblen); | |
891 | xfree(blob); | |
892 | packet_send(); | |
893 | return 1; | |
894 | } | |
895 | ||
896 | Key * | |
897 | load_identity_file(char *filename) | |
898 | { | |
899 | Key *private; | |
900 | char prompt[300], *passphrase; | |
901 | int success = 0, quit, i; | |
d156519a | 902 | struct stat st; |
fee56204 | 903 | |
d156519a | 904 | if (stat(filename, &st) < 0) { |
905 | debug3("no such identity: %s", filename); | |
906 | return NULL; | |
907 | } | |
fee56204 | 908 | private = key_new(KEY_UNSPEC); |
909 | if (!load_private_key(filename, "", private, NULL)) { | |
f72e01a5 | 910 | if (options.batch_mode) { |
fee56204 | 911 | key_free(private); |
912 | return NULL; | |
f72e01a5 | 913 | } |
4c8722d9 | 914 | snprintf(prompt, sizeof prompt, |
fa08c86b | 915 | "Enter passphrase for key '%.100s': ", filename); |
188adeb2 | 916 | for (i = 0; i < options.number_of_password_prompts; i++) { |
917 | passphrase = read_passphrase(prompt, 0); | |
918 | if (strcmp(passphrase, "") != 0) { | |
fee56204 | 919 | success = load_private_key(filename, |
920 | passphrase, private, NULL); | |
921 | quit = 0; | |
188adeb2 | 922 | } else { |
923 | debug2("no passphrase given, try next key"); | |
fee56204 | 924 | quit = 1; |
188adeb2 | 925 | } |
926 | memset(passphrase, 0, strlen(passphrase)); | |
927 | xfree(passphrase); | |
fee56204 | 928 | if (success || quit) |
188adeb2 | 929 | break; |
930 | debug2("bad passphrase given, try again..."); | |
931 | } | |
4c8722d9 | 932 | if (!success) { |
fee56204 | 933 | key_free(private); |
934 | return NULL; | |
4c8722d9 | 935 | } |
936 | } | |
fee56204 | 937 | return private; |
938 | } | |
939 | ||
940 | int | |
941 | identity_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp, | |
942 | u_char *data, int datalen) | |
943 | { | |
944 | Key *private; | |
945 | int idx, ret; | |
946 | ||
947 | idx = authctxt->last_key_hint; | |
948 | if (idx < 0) | |
949 | return -1; | |
950 | private = load_identity_file(options.identity_files[idx]); | |
951 | if (private == NULL) | |
952 | return -1; | |
953 | ret = key_sign(private, sigp, lenp, data, datalen); | |
954 | key_free(private); | |
2e73a022 | 955 | return ret; |
956 | } | |
957 | ||
1e3b8b07 | 958 | int agent_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp, |
959 | u_char *data, int datalen) | |
2e73a022 | 960 | { |
188adeb2 | 961 | return ssh_agent_sign(authctxt->agent, key, sigp, lenp, data, datalen); |
2e73a022 | 962 | } |
963 | ||
fee56204 | 964 | int key_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp, |
965 | u_char *data, int datalen) | |
966 | { | |
967 | return key_sign(key, sigp, lenp, data, datalen); | |
968 | } | |
969 | ||
2e73a022 | 970 | int |
188adeb2 | 971 | userauth_pubkey_agent(Authctxt *authctxt) |
2e73a022 | 972 | { |
973 | static int called = 0; | |
fa08c86b | 974 | int ret = 0; |
2e73a022 | 975 | char *comment; |
976 | Key *k; | |
2e73a022 | 977 | |
978 | if (called == 0) { | |
fa08c86b | 979 | if (ssh_get_num_identities(authctxt->agent, 2) == 0) |
980 | debug2("userauth_pubkey_agent: no keys at all"); | |
188adeb2 | 981 | called = 1; |
2e73a022 | 982 | } |
fa08c86b | 983 | k = ssh_get_next_identity(authctxt->agent, &comment, 2); |
188adeb2 | 984 | if (k == NULL) { |
fa08c86b | 985 | debug2("userauth_pubkey_agent: no more keys"); |
986 | } else { | |
fee56204 | 987 | debug("userauth_pubkey_agent: testing agent key %s", comment); |
fa08c86b | 988 | xfree(comment); |
fee56204 | 989 | ret = send_pubkey_test(authctxt, k, agent_sign_cb, -1); |
990 | if (ret == 0) | |
991 | key_free(k); | |
188adeb2 | 992 | } |
fa08c86b | 993 | if (ret == 0) |
994 | debug2("userauth_pubkey_agent: no message sent"); | |
2e73a022 | 995 | return ret; |
a306f2dd | 996 | } |
997 | ||
188adeb2 | 998 | int |
999 | userauth_pubkey(Authctxt *authctxt) | |
a306f2dd | 1000 | { |
188adeb2 | 1001 | static int idx = 0; |
1002 | int sent = 0; | |
fee56204 | 1003 | Key *key; |
1004 | char *filename; | |
188adeb2 | 1005 | |
fa08c86b | 1006 | if (authctxt->agent != NULL) { |
1007 | do { | |
1008 | sent = userauth_pubkey_agent(authctxt); | |
1009 | } while(!sent && authctxt->agent->howmany > 0); | |
1010 | } | |
1011 | while (!sent && idx < options.num_identity_files) { | |
fee56204 | 1012 | key = options.identity_keys[idx]; |
1013 | filename = options.identity_files[idx]; | |
1014 | if (key == NULL) { | |
1015 | debug("try privkey: %s", filename); | |
1016 | key = load_identity_file(filename); | |
1017 | if (key != NULL) { | |
1018 | sent = sign_and_send_pubkey(authctxt, key, | |
1019 | key_sign_cb); | |
1020 | key_free(key); | |
1021 | } | |
1022 | } else if (key->type != KEY_RSA1) { | |
1023 | debug("try pubkey: %s", filename); | |
1024 | sent = send_pubkey_test(authctxt, key, | |
1025 | identity_sign_cb, idx); | |
1026 | } | |
fa08c86b | 1027 | idx++; |
1028 | } | |
188adeb2 | 1029 | return sent; |
1030 | } | |
a306f2dd | 1031 | |
94ec8c6b | 1032 | /* |
1033 | * Send userauth request message specifying keyboard-interactive method. | |
1034 | */ | |
1035 | int | |
1036 | userauth_kbdint(Authctxt *authctxt) | |
1037 | { | |
1038 | static int attempt = 0; | |
1039 | ||
1040 | if (attempt++ >= options.number_of_password_prompts) | |
1041 | return 0; | |
1042 | ||
1043 | debug2("userauth_kbdint"); | |
1044 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
1045 | packet_put_cstring(authctxt->server_user); | |
1046 | packet_put_cstring(authctxt->service); | |
1047 | packet_put_cstring(authctxt->method->name); | |
1048 | packet_put_cstring(""); /* lang */ | |
1049 | packet_put_cstring(options.kbd_interactive_devices ? | |
1050 | options.kbd_interactive_devices : ""); | |
1051 | packet_send(); | |
94ec8c6b | 1052 | |
1053 | dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req); | |
1054 | return 1; | |
1055 | } | |
1056 | ||
1057 | /* | |
f72e01a5 | 1058 | * parse INFO_REQUEST, prompt user and send INFO_RESPONSE |
94ec8c6b | 1059 | */ |
1060 | void | |
1061 | input_userauth_info_req(int type, int plen, void *ctxt) | |
1062 | { | |
1063 | Authctxt *authctxt = ctxt; | |
f72e01a5 | 1064 | char *name, *inst, *lang, *prompt, *response; |
1e3b8b07 | 1065 | u_int num_prompts, i; |
94ec8c6b | 1066 | int echo = 0; |
1067 | ||
1068 | debug2("input_userauth_info_req"); | |
1069 | ||
1070 | if (authctxt == NULL) | |
1071 | fatal("input_userauth_info_req: no authentication context"); | |
1072 | ||
1073 | name = packet_get_string(NULL); | |
1074 | inst = packet_get_string(NULL); | |
1075 | lang = packet_get_string(NULL); | |
94ec8c6b | 1076 | if (strlen(name) > 0) |
1077 | cli_mesg(name); | |
94ec8c6b | 1078 | if (strlen(inst) > 0) |
1079 | cli_mesg(inst); | |
f72e01a5 | 1080 | xfree(name); |
94ec8c6b | 1081 | xfree(inst); |
f72e01a5 | 1082 | xfree(lang); |
94ec8c6b | 1083 | |
1084 | num_prompts = packet_get_int(); | |
1085 | /* | |
1086 | * Begin to build info response packet based on prompts requested. | |
1087 | * We commit to providing the correct number of responses, so if | |
1088 | * further on we run into a problem that prevents this, we have to | |
1089 | * be sure and clean this up and send a correct error response. | |
1090 | */ | |
1091 | packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE); | |
1092 | packet_put_int(num_prompts); | |
1093 | ||
1094 | for (i = 0; i < num_prompts; i++) { | |
1095 | prompt = packet_get_string(NULL); | |
1096 | echo = packet_get_char(); | |
1097 | ||
1098 | response = cli_prompt(prompt, echo); | |
1099 | ||
a6215e53 | 1100 | packet_put_cstring(response); |
94ec8c6b | 1101 | memset(response, 0, strlen(response)); |
1102 | xfree(response); | |
1103 | xfree(prompt); | |
1104 | } | |
1105 | packet_done(); /* done with parsing incoming message. */ | |
1106 | ||
a6215e53 | 1107 | packet_inject_ignore(64); |
94ec8c6b | 1108 | packet_send(); |
94ec8c6b | 1109 | } |
a306f2dd | 1110 | |
188adeb2 | 1111 | /* find auth method */ |
1112 | ||
188adeb2 | 1113 | /* |
1114 | * given auth method name, if configurable options permit this method fill | |
1115 | * in auth_ident field and return true, otherwise return false. | |
1116 | */ | |
1117 | int | |
1118 | authmethod_is_enabled(Authmethod *method) | |
1119 | { | |
1120 | if (method == NULL) | |
1121 | return 0; | |
1122 | /* return false if options indicate this method is disabled */ | |
1123 | if (method->enabled == NULL || *method->enabled == 0) | |
1124 | return 0; | |
1125 | /* return false if batch mode is enabled but method needs interactive mode */ | |
1126 | if (method->batch_flag != NULL && *method->batch_flag != 0) | |
1127 | return 0; | |
1128 | return 1; | |
1129 | } | |
a306f2dd | 1130 | |
188adeb2 | 1131 | Authmethod * |
1132 | authmethod_lookup(const char *name) | |
1133 | { | |
1134 | Authmethod *method = NULL; | |
1135 | if (name != NULL) | |
1136 | for (method = authmethods; method->name != NULL; method++) | |
1137 | if (strcmp(name, method->name) == 0) | |
1138 | return method; | |
1139 | debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); | |
1140 | return NULL; | |
1141 | } | |
1142 | ||
cab80f75 | 1143 | /* XXX internal state */ |
1144 | static Authmethod *current = NULL; | |
1145 | static char *supported = NULL; | |
1146 | static char *preferred = NULL; | |
188adeb2 | 1147 | /* |
1148 | * Given the authentication method list sent by the server, return the | |
1149 | * next method we should try. If the server initially sends a nil list, | |
cab80f75 | 1150 | * use a built-in default list. |
2b87da3b | 1151 | */ |
188adeb2 | 1152 | Authmethod * |
1153 | authmethod_get(char *authlist) | |
1154 | { | |
cab80f75 | 1155 | |
1156 | char *name = NULL; | |
1157 | int next; | |
2b87da3b | 1158 | |
188adeb2 | 1159 | /* Use a suitable default if we're passed a nil list. */ |
1160 | if (authlist == NULL || strlen(authlist) == 0) | |
cab80f75 | 1161 | authlist = options.preferred_authentications; |
1162 | ||
1163 | if (supported == NULL || strcmp(authlist, supported) != 0) { | |
1164 | debug3("start over, passed a different list %s", authlist); | |
1165 | if (supported != NULL) | |
1166 | xfree(supported); | |
1167 | supported = xstrdup(authlist); | |
1168 | preferred = options.preferred_authentications; | |
1169 | debug3("preferred %s", preferred); | |
1170 | current = NULL; | |
1171 | } else if (current != NULL && authmethod_is_enabled(current)) | |
1172 | return current; | |
188adeb2 | 1173 | |
cab80f75 | 1174 | for (;;) { |
1175 | if ((name = match_list(preferred, supported, &next)) == NULL) { | |
1176 | debug("no more auth methods to try"); | |
1177 | current = NULL; | |
1178 | return NULL; | |
1179 | } | |
1180 | preferred += next; | |
94ec8c6b | 1181 | debug3("authmethod_lookup %s", name); |
cab80f75 | 1182 | debug3("remaining preferred: %s", preferred); |
1183 | if ((current = authmethod_lookup(name)) != NULL && | |
1184 | authmethod_is_enabled(current)) { | |
94ec8c6b | 1185 | debug3("authmethod_is_enabled %s", name); |
cab80f75 | 1186 | debug("next auth method to try is %s", name); |
1187 | return current; | |
94ec8c6b | 1188 | } |
a306f2dd | 1189 | } |
cab80f75 | 1190 | } |
a22aff1f | 1191 | |
a22aff1f | 1192 | |
cab80f75 | 1193 | #define DELIM "," |
1194 | char * | |
1195 | authmethods_get(void) | |
1196 | { | |
1197 | Authmethod *method = NULL; | |
1198 | char buf[1024]; | |
1199 | ||
1200 | buf[0] = '\0'; | |
1201 | for (method = authmethods; method->name != NULL; method++) { | |
1202 | if (authmethod_is_enabled(method)) { | |
1203 | if (buf[0] != '\0') | |
1204 | strlcat(buf, DELIM, sizeof buf); | |
1205 | strlcat(buf, method->name, sizeof buf); | |
1206 | } | |
1207 | } | |
1208 | return xstrdup(buf); | |
a306f2dd | 1209 | } |