]>
Commit | Line | Data |
---|---|---|
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" | |
fee56204 | 26 | RCSID("$OpenBSD: sshconnect2.c,v 1.51 2001/03/08 21:42:33 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" | |
a306f2dd | 54 | |
94ec8c6b | 55 | void ssh_dh1_client(Kex *, char *, struct sockaddr *, Buffer *, Buffer *); |
56 | void ssh_dhgex_client(Kex *, char *, struct sockaddr *, Buffer *, Buffer *); | |
57 | ||
a306f2dd | 58 | /* import */ |
59 | extern char *client_version_string; | |
60 | extern char *server_version_string; | |
61 | extern Options options; | |
62 | ||
63 | /* | |
64 | * SSH2 key exchange | |
65 | */ | |
66 | ||
1e3b8b07 | 67 | u_char *session_id2 = NULL; |
a306f2dd | 68 | int session_id2_len = 0; |
69 | ||
70 | void | |
94ec8c6b | 71 | ssh_kex2(char *host, struct sockaddr *hostaddr) |
72 | { | |
73 | int i, plen; | |
74 | Kex *kex; | |
75 | Buffer *client_kexinit, *server_kexinit; | |
76 | char *sprop[PROPOSAL_MAX]; | |
77 | ||
c523303b | 78 | if (options.ciphers == (char *)-1) { |
79 | log("No valid ciphers for protocol version 2 given, using defaults."); | |
80 | options.ciphers = NULL; | |
94ec8c6b | 81 | } |
82 | if (options.ciphers != NULL) { | |
83 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = | |
84 | myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; | |
85 | } | |
86 | if (options.compression) { | |
b2552997 | 87 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = |
94ec8c6b | 88 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib"; |
89 | } else { | |
b2552997 | 90 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = |
94ec8c6b | 91 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none"; |
92 | } | |
b2552997 | 93 | if (options.macs != NULL) { |
94 | myproposal[PROPOSAL_MAC_ALGS_CTOS] = | |
95 | myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; | |
96 | } | |
94ec8c6b | 97 | |
98 | /* buffers with raw kexinit messages */ | |
99 | server_kexinit = xmalloc(sizeof(*server_kexinit)); | |
100 | buffer_init(server_kexinit); | |
101 | client_kexinit = kex_init(myproposal); | |
102 | ||
103 | /* algorithm negotiation */ | |
104 | kex_exchange_kexinit(client_kexinit, server_kexinit, sprop); | |
105 | kex = kex_choose_conf(myproposal, sprop, 0); | |
106 | for (i = 0; i < PROPOSAL_MAX; i++) | |
107 | xfree(sprop[i]); | |
108 | ||
109 | /* server authentication and session key agreement */ | |
110 | switch(kex->kex_type) { | |
111 | case DH_GRP1_SHA1: | |
112 | ssh_dh1_client(kex, host, hostaddr, | |
113 | client_kexinit, server_kexinit); | |
114 | break; | |
115 | case DH_GEX_SHA1: | |
116 | ssh_dhgex_client(kex, host, hostaddr, client_kexinit, | |
117 | server_kexinit); | |
118 | break; | |
119 | default: | |
120 | fatal("Unsupported key exchange %d", kex->kex_type); | |
121 | } | |
122 | ||
123 | buffer_free(client_kexinit); | |
124 | buffer_free(server_kexinit); | |
125 | xfree(client_kexinit); | |
126 | xfree(server_kexinit); | |
127 | ||
128 | debug("Wait SSH2_MSG_NEWKEYS."); | |
129 | packet_read_expect(&plen, SSH2_MSG_NEWKEYS); | |
130 | packet_done(); | |
131 | debug("GOT SSH2_MSG_NEWKEYS."); | |
132 | ||
133 | debug("send SSH2_MSG_NEWKEYS."); | |
134 | packet_start(SSH2_MSG_NEWKEYS); | |
135 | packet_send(); | |
136 | packet_write_wait(); | |
137 | debug("done: send SSH2_MSG_NEWKEYS."); | |
138 | ||
139 | #ifdef DEBUG_KEXDH | |
140 | /* send 1st encrypted/maced/compressed message */ | |
141 | packet_start(SSH2_MSG_IGNORE); | |
142 | packet_put_cstring("markus"); | |
143 | packet_send(); | |
144 | packet_write_wait(); | |
145 | #endif | |
146 | debug("done: KEX2."); | |
147 | } | |
148 | ||
149 | /* diffie-hellman-group1-sha1 */ | |
150 | ||
151 | void | |
2b87da3b | 152 | ssh_dh1_client(Kex *kex, char *host, struct sockaddr *hostaddr, |
94ec8c6b | 153 | Buffer *client_kexinit, Buffer *server_kexinit) |
a306f2dd | 154 | { |
188adeb2 | 155 | #ifdef DEBUG_KEXDH |
156 | int i; | |
157 | #endif | |
71276795 | 158 | int plen, dlen; |
1e3b8b07 | 159 | u_int klen, kout; |
a306f2dd | 160 | char *signature = NULL; |
1e3b8b07 | 161 | u_int slen; |
a306f2dd | 162 | char *server_host_key_blob = NULL; |
163 | Key *server_host_key; | |
1e3b8b07 | 164 | u_int sbloblen; |
a306f2dd | 165 | DH *dh; |
166 | BIGNUM *dh_server_pub = 0; | |
167 | BIGNUM *shared_secret = 0; | |
1e3b8b07 | 168 | u_char *kbuf; |
169 | u_char *hash; | |
a306f2dd | 170 | |
a306f2dd | 171 | debug("Sending SSH2_MSG_KEXDH_INIT."); |
a306f2dd | 172 | /* generate and send 'e', client DH public key */ |
173 | dh = dh_new_group1(); | |
7de5b06b | 174 | dh_gen_key(dh, kex->we_need * 8); |
a306f2dd | 175 | packet_start(SSH2_MSG_KEXDH_INIT); |
176 | packet_put_bignum2(dh->pub_key); | |
177 | packet_send(); | |
178 | packet_write_wait(); | |
179 | ||
180 | #ifdef DEBUG_KEXDH | |
181 | fprintf(stderr, "\np= "); | |
188adeb2 | 182 | BN_print_fp(stderr, dh->p); |
a306f2dd | 183 | fprintf(stderr, "\ng= "); |
188adeb2 | 184 | BN_print_fp(stderr, dh->g); |
a306f2dd | 185 | fprintf(stderr, "\npub= "); |
188adeb2 | 186 | BN_print_fp(stderr, dh->pub_key); |
a306f2dd | 187 | fprintf(stderr, "\n"); |
188 | DHparams_print_fp(stderr, dh); | |
189 | #endif | |
190 | ||
191 | debug("Wait SSH2_MSG_KEXDH_REPLY."); | |
192 | ||
71276795 | 193 | packet_read_expect(&plen, SSH2_MSG_KEXDH_REPLY); |
a306f2dd | 194 | |
195 | debug("Got SSH2_MSG_KEXDH_REPLY."); | |
196 | ||
197 | /* key, cert */ | |
198 | server_host_key_blob = packet_get_string(&sbloblen); | |
fa08c86b | 199 | server_host_key = key_from_blob(server_host_key_blob, sbloblen); |
a306f2dd | 200 | if (server_host_key == NULL) |
201 | fatal("cannot decode server_host_key_blob"); | |
202 | ||
203 | check_host_key(host, hostaddr, server_host_key, | |
94ec8c6b | 204 | options.user_hostfile2, options.system_hostfile2); |
a306f2dd | 205 | |
206 | /* DH paramter f, server public DH key */ | |
207 | dh_server_pub = BN_new(); | |
208 | if (dh_server_pub == NULL) | |
209 | fatal("dh_server_pub == NULL"); | |
210 | packet_get_bignum2(dh_server_pub, &dlen); | |
211 | ||
212 | #ifdef DEBUG_KEXDH | |
213 | fprintf(stderr, "\ndh_server_pub= "); | |
188adeb2 | 214 | BN_print_fp(stderr, dh_server_pub); |
a306f2dd | 215 | fprintf(stderr, "\n"); |
216 | debug("bits %d", BN_num_bits(dh_server_pub)); | |
217 | #endif | |
218 | ||
219 | /* signed H */ | |
220 | signature = packet_get_string(&slen); | |
221 | packet_done(); | |
222 | ||
223 | if (!dh_pub_is_valid(dh, dh_server_pub)) | |
224 | packet_disconnect("bad server public DH value"); | |
225 | ||
226 | klen = DH_size(dh); | |
227 | kbuf = xmalloc(klen); | |
228 | kout = DH_compute_key(kbuf, dh_server_pub, dh); | |
229 | #ifdef DEBUG_KEXDH | |
230 | debug("shared secret: len %d/%d", klen, kout); | |
231 | fprintf(stderr, "shared secret == "); | |
232 | for (i = 0; i< kout; i++) | |
233 | fprintf(stderr, "%02x", (kbuf[i])&0xff); | |
234 | fprintf(stderr, "\n"); | |
235 | #endif | |
236 | shared_secret = BN_new(); | |
237 | ||
238 | BN_bin2bn(kbuf, kout, shared_secret); | |
239 | memset(kbuf, 0, klen); | |
240 | xfree(kbuf); | |
241 | ||
242 | /* calc and verify H */ | |
243 | hash = kex_hash( | |
244 | client_version_string, | |
245 | server_version_string, | |
246 | buffer_ptr(client_kexinit), buffer_len(client_kexinit), | |
247 | buffer_ptr(server_kexinit), buffer_len(server_kexinit), | |
248 | server_host_key_blob, sbloblen, | |
249 | dh->pub_key, | |
250 | dh_server_pub, | |
251 | shared_secret | |
252 | ); | |
253 | xfree(server_host_key_blob); | |
71276795 | 254 | DH_free(dh); |
53a24016 | 255 | BN_free(dh_server_pub); |
a306f2dd | 256 | #ifdef DEBUG_KEXDH |
257 | fprintf(stderr, "hash == "); | |
258 | for (i = 0; i< 20; i++) | |
259 | fprintf(stderr, "%02x", (hash[i])&0xff); | |
260 | fprintf(stderr, "\n"); | |
261 | #endif | |
1e3b8b07 | 262 | if (key_verify(server_host_key, (u_char *)signature, slen, hash, 20) != 1) |
fa08c86b | 263 | fatal("key_verify failed for server_host_key"); |
a306f2dd | 264 | key_free(server_host_key); |
53a24016 | 265 | xfree(signature); |
a306f2dd | 266 | |
267 | kex_derive_keys(kex, hash, shared_secret); | |
53a24016 | 268 | BN_clear_free(shared_secret); |
a306f2dd | 269 | packet_set_kex(kex); |
270 | ||
a306f2dd | 271 | /* save session id */ |
272 | session_id2_len = 20; | |
273 | session_id2 = xmalloc(session_id2_len); | |
274 | memcpy(session_id2, hash, session_id2_len); | |
71276795 | 275 | } |
276 | ||
94ec8c6b | 277 | /* diffie-hellman-group-exchange-sha1 */ |
278 | ||
279 | /* | |
280 | * Estimates the group order for a Diffie-Hellman group that has an | |
281 | * attack complexity approximately the same as O(2**bits). Estimate | |
282 | * with: O(exp(1.9223 * (ln q)^(1/3) (ln ln q)^(2/3))) | |
283 | */ | |
284 | ||
285 | int | |
286 | dh_estimate(int bits) | |
287 | { | |
2b87da3b | 288 | |
94ec8c6b | 289 | if (bits < 64) |
290 | return (512); /* O(2**63) */ | |
291 | if (bits < 128) | |
292 | return (1024); /* O(2**86) */ | |
293 | if (bits < 192) | |
294 | return (2048); /* O(2**116) */ | |
295 | return (4096); /* O(2**156) */ | |
296 | } | |
297 | ||
71276795 | 298 | void |
94ec8c6b | 299 | ssh_dhgex_client(Kex *kex, char *host, struct sockaddr *hostaddr, |
300 | Buffer *client_kexinit, Buffer *server_kexinit) | |
71276795 | 301 | { |
94ec8c6b | 302 | #ifdef DEBUG_KEXDH |
303 | int i; | |
304 | #endif | |
305 | int plen, dlen; | |
1e3b8b07 | 306 | u_int klen, kout; |
94ec8c6b | 307 | char *signature = NULL; |
1e3b8b07 | 308 | u_int slen, nbits; |
94ec8c6b | 309 | char *server_host_key_blob = NULL; |
310 | Key *server_host_key; | |
1e3b8b07 | 311 | u_int sbloblen; |
94ec8c6b | 312 | DH *dh; |
313 | BIGNUM *dh_server_pub = 0; | |
314 | BIGNUM *shared_secret = 0; | |
315 | BIGNUM *p = 0, *g = 0; | |
1e3b8b07 | 316 | u_char *kbuf; |
317 | u_char *hash; | |
71276795 | 318 | |
7de5b06b | 319 | nbits = dh_estimate(kex->we_need * 8); |
71276795 | 320 | |
94ec8c6b | 321 | debug("Sending SSH2_MSG_KEX_DH_GEX_REQUEST."); |
322 | packet_start(SSH2_MSG_KEX_DH_GEX_REQUEST); | |
323 | packet_put_int(nbits); | |
324 | packet_send(); | |
325 | packet_write_wait(); | |
71276795 | 326 | |
94ec8c6b | 327 | #ifdef DEBUG_KEXDH |
328 | fprintf(stderr, "\nnbits = %d", nbits); | |
329 | #endif | |
71276795 | 330 | |
94ec8c6b | 331 | debug("Wait SSH2_MSG_KEX_DH_GEX_GROUP."); |
71276795 | 332 | |
94ec8c6b | 333 | packet_read_expect(&plen, SSH2_MSG_KEX_DH_GEX_GROUP); |
a306f2dd | 334 | |
94ec8c6b | 335 | debug("Got SSH2_MSG_KEX_DH_GEX_GROUP."); |
a306f2dd | 336 | |
94ec8c6b | 337 | if ((p = BN_new()) == NULL) |
338 | fatal("BN_new"); | |
339 | packet_get_bignum2(p, &dlen); | |
340 | if ((g = BN_new()) == NULL) | |
341 | fatal("BN_new"); | |
342 | packet_get_bignum2(g, &dlen); | |
42f11eb2 | 343 | dh = dh_new_group(g, p); |
a306f2dd | 344 | |
7de5b06b | 345 | dh_gen_key(dh, kex->we_need * 8); |
3e1caa83 | 346 | |
a306f2dd | 347 | #ifdef DEBUG_KEXDH |
94ec8c6b | 348 | fprintf(stderr, "\np= "); |
349 | BN_print_fp(stderr, dh->p); | |
350 | fprintf(stderr, "\ng= "); | |
351 | BN_print_fp(stderr, dh->g); | |
352 | fprintf(stderr, "\npub= "); | |
353 | BN_print_fp(stderr, dh->pub_key); | |
354 | fprintf(stderr, "\n"); | |
355 | DHparams_print_fp(stderr, dh); | |
356 | #endif | |
357 | ||
358 | debug("Sending SSH2_MSG_KEX_DH_GEX_INIT."); | |
359 | /* generate and send 'e', client DH public key */ | |
360 | packet_start(SSH2_MSG_KEX_DH_GEX_INIT); | |
361 | packet_put_bignum2(dh->pub_key); | |
a306f2dd | 362 | packet_send(); |
363 | packet_write_wait(); | |
94ec8c6b | 364 | |
365 | debug("Wait SSH2_MSG_KEX_DH_GEX_REPLY."); | |
366 | ||
367 | packet_read_expect(&plen, SSH2_MSG_KEX_DH_GEX_REPLY); | |
368 | ||
369 | debug("Got SSH2_MSG_KEXDH_REPLY."); | |
370 | ||
371 | /* key, cert */ | |
372 | server_host_key_blob = packet_get_string(&sbloblen); | |
fa08c86b | 373 | server_host_key = key_from_blob(server_host_key_blob, sbloblen); |
94ec8c6b | 374 | if (server_host_key == NULL) |
375 | fatal("cannot decode server_host_key_blob"); | |
376 | ||
377 | check_host_key(host, hostaddr, server_host_key, | |
378 | options.user_hostfile2, options.system_hostfile2); | |
379 | ||
380 | /* DH paramter f, server public DH key */ | |
381 | dh_server_pub = BN_new(); | |
382 | if (dh_server_pub == NULL) | |
383 | fatal("dh_server_pub == NULL"); | |
384 | packet_get_bignum2(dh_server_pub, &dlen); | |
385 | ||
386 | #ifdef DEBUG_KEXDH | |
387 | fprintf(stderr, "\ndh_server_pub= "); | |
388 | BN_print_fp(stderr, dh_server_pub); | |
389 | fprintf(stderr, "\n"); | |
390 | debug("bits %d", BN_num_bits(dh_server_pub)); | |
a306f2dd | 391 | #endif |
94ec8c6b | 392 | |
393 | /* signed H */ | |
394 | signature = packet_get_string(&slen); | |
395 | packet_done(); | |
396 | ||
397 | if (!dh_pub_is_valid(dh, dh_server_pub)) | |
398 | packet_disconnect("bad server public DH value"); | |
399 | ||
400 | klen = DH_size(dh); | |
401 | kbuf = xmalloc(klen); | |
402 | kout = DH_compute_key(kbuf, dh_server_pub, dh); | |
403 | #ifdef DEBUG_KEXDH | |
404 | debug("shared secret: len %d/%d", klen, kout); | |
405 | fprintf(stderr, "shared secret == "); | |
406 | for (i = 0; i< kout; i++) | |
407 | fprintf(stderr, "%02x", (kbuf[i])&0xff); | |
408 | fprintf(stderr, "\n"); | |
409 | #endif | |
410 | shared_secret = BN_new(); | |
411 | ||
412 | BN_bin2bn(kbuf, kout, shared_secret); | |
413 | memset(kbuf, 0, klen); | |
414 | xfree(kbuf); | |
415 | ||
416 | /* calc and verify H */ | |
417 | hash = kex_hash_gex( | |
418 | client_version_string, | |
419 | server_version_string, | |
420 | buffer_ptr(client_kexinit), buffer_len(client_kexinit), | |
421 | buffer_ptr(server_kexinit), buffer_len(server_kexinit), | |
422 | server_host_key_blob, sbloblen, | |
2b87da3b | 423 | nbits, dh->p, dh->g, |
94ec8c6b | 424 | dh->pub_key, |
425 | dh_server_pub, | |
426 | shared_secret | |
427 | ); | |
428 | xfree(server_host_key_blob); | |
429 | DH_free(dh); | |
53a24016 | 430 | BN_free(dh_server_pub); |
94ec8c6b | 431 | #ifdef DEBUG_KEXDH |
432 | fprintf(stderr, "hash == "); | |
433 | for (i = 0; i< 20; i++) | |
434 | fprintf(stderr, "%02x", (hash[i])&0xff); | |
435 | fprintf(stderr, "\n"); | |
436 | #endif | |
1e3b8b07 | 437 | if (key_verify(server_host_key, (u_char *)signature, slen, hash, 20) != 1) |
fa08c86b | 438 | fatal("key_verify failed for server_host_key"); |
94ec8c6b | 439 | key_free(server_host_key); |
53a24016 | 440 | xfree(signature); |
94ec8c6b | 441 | |
442 | kex_derive_keys(kex, hash, shared_secret); | |
53a24016 | 443 | BN_clear_free(shared_secret); |
94ec8c6b | 444 | packet_set_kex(kex); |
445 | ||
446 | /* save session id */ | |
447 | session_id2_len = 20; | |
448 | session_id2 = xmalloc(session_id2_len); | |
449 | memcpy(session_id2, hash, session_id2_len); | |
a306f2dd | 450 | } |
71276795 | 451 | |
a306f2dd | 452 | /* |
453 | * Authenticate user | |
454 | */ | |
188adeb2 | 455 | |
456 | typedef struct Authctxt Authctxt; | |
457 | typedef struct Authmethod Authmethod; | |
458 | ||
459 | typedef int sign_cb_fn( | |
460 | Authctxt *authctxt, Key *key, | |
1e3b8b07 | 461 | u_char **sigp, int *lenp, u_char *data, int datalen); |
188adeb2 | 462 | |
463 | struct Authctxt { | |
464 | const char *server_user; | |
465 | const char *host; | |
466 | const char *service; | |
467 | AuthenticationConnection *agent; | |
188adeb2 | 468 | Authmethod *method; |
94ec8c6b | 469 | int success; |
fee56204 | 470 | char *authlist; |
471 | Key *last_key; | |
472 | sign_cb_fn *last_key_sign; | |
473 | int last_key_hint; | |
188adeb2 | 474 | }; |
475 | struct Authmethod { | |
476 | char *name; /* string to compare against server's list */ | |
477 | int (*userauth)(Authctxt *authctxt); | |
478 | int *enabled; /* flag in option struct that enables method */ | |
479 | int *batch_flag; /* flag in option struct that disables method */ | |
480 | }; | |
481 | ||
482 | void input_userauth_success(int type, int plen, void *ctxt); | |
483 | void input_userauth_failure(int type, int plen, void *ctxt); | |
9616313f | 484 | void input_userauth_banner(int type, int plen, void *ctxt); |
188adeb2 | 485 | void input_userauth_error(int type, int plen, void *ctxt); |
94ec8c6b | 486 | void input_userauth_info_req(int type, int plen, void *ctxt); |
fee56204 | 487 | void input_userauth_pk_ok(int type, int plen, void *ctxt); |
94ec8c6b | 488 | |
489 | int userauth_none(Authctxt *authctxt); | |
188adeb2 | 490 | int userauth_pubkey(Authctxt *authctxt); |
491 | int userauth_passwd(Authctxt *authctxt); | |
94ec8c6b | 492 | int userauth_kbdint(Authctxt *authctxt); |
188adeb2 | 493 | |
fee56204 | 494 | void userauth(Authctxt *authctxt, char *authlist); |
495 | ||
496 | int | |
497 | sign_and_send_pubkey(Authctxt *authctxt, Key *k, | |
498 | sign_cb_fn *sign_callback); | |
499 | void clear_auth_state(Authctxt *authctxt); | |
500 | ||
1e3b8b07 | 501 | void authmethod_clear(void); |
94ec8c6b | 502 | Authmethod *authmethod_get(char *authlist); |
503 | Authmethod *authmethod_lookup(const char *name); | |
188adeb2 | 504 | |
505 | Authmethod authmethods[] = { | |
506 | {"publickey", | |
507 | userauth_pubkey, | |
fa08c86b | 508 | &options.pubkey_authentication, |
188adeb2 | 509 | NULL}, |
510 | {"password", | |
511 | userauth_passwd, | |
512 | &options.password_authentication, | |
513 | &options.batch_mode}, | |
94ec8c6b | 514 | {"keyboard-interactive", |
515 | userauth_kbdint, | |
516 | &options.kbd_interactive_authentication, | |
517 | &options.batch_mode}, | |
518 | {"none", | |
519 | userauth_none, | |
520 | NULL, | |
521 | NULL}, | |
188adeb2 | 522 | {NULL, NULL, NULL, NULL} |
523 | }; | |
524 | ||
525 | void | |
526 | ssh_userauth2(const char *server_user, char *host) | |
527 | { | |
528 | Authctxt authctxt; | |
529 | int type; | |
530 | int plen; | |
531 | ||
d464095c | 532 | if (options.challenge_reponse_authentication) |
533 | options.kbd_interactive_authentication = 1; | |
534 | ||
188adeb2 | 535 | debug("send SSH2_MSG_SERVICE_REQUEST"); |
536 | packet_start(SSH2_MSG_SERVICE_REQUEST); | |
537 | packet_put_cstring("ssh-userauth"); | |
538 | packet_send(); | |
539 | packet_write_wait(); | |
540 | type = packet_read(&plen); | |
541 | if (type != SSH2_MSG_SERVICE_ACCEPT) { | |
542 | fatal("denied SSH2_MSG_SERVICE_ACCEPT: %d", type); | |
543 | } | |
544 | if (packet_remaining() > 0) { | |
545 | char *reply = packet_get_string(&plen); | |
546 | debug("service_accept: %s", reply); | |
547 | xfree(reply); | |
188adeb2 | 548 | } else { |
549 | debug("buggy server: service_accept w/o service"); | |
550 | } | |
551 | packet_done(); | |
552 | debug("got SSH2_MSG_SERVICE_ACCEPT"); | |
553 | ||
554 | /* setup authentication context */ | |
555 | authctxt.agent = ssh_get_authentication_connection(); | |
556 | authctxt.server_user = server_user; | |
557 | authctxt.host = host; | |
558 | authctxt.service = "ssh-connection"; /* service name */ | |
559 | authctxt.success = 0; | |
94ec8c6b | 560 | authctxt.method = authmethod_lookup("none"); |
fee56204 | 561 | authctxt.authlist = NULL; |
94ec8c6b | 562 | if (authctxt.method == NULL) |
563 | fatal("ssh_userauth2: internal error: cannot send userauth none request"); | |
564 | authmethod_clear(); | |
188adeb2 | 565 | |
566 | /* initial userauth request */ | |
94ec8c6b | 567 | userauth_none(&authctxt); |
188adeb2 | 568 | |
569 | dispatch_init(&input_userauth_error); | |
570 | dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); | |
571 | dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure); | |
9616313f | 572 | dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner); |
188adeb2 | 573 | dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */ |
574 | ||
575 | if (authctxt.agent != NULL) | |
576 | ssh_close_authentication_connection(authctxt.agent); | |
577 | ||
8abcdba4 | 578 | debug("ssh-userauth2 successful: method %s", authctxt.method->name); |
188adeb2 | 579 | } |
580 | void | |
fee56204 | 581 | userauth(Authctxt *authctxt, char *authlist) |
582 | { | |
583 | if (authlist == NULL) { | |
584 | authlist = authctxt->authlist; | |
585 | } else { | |
586 | if (authctxt->authlist) | |
587 | xfree(authctxt->authlist); | |
588 | authctxt->authlist = authlist; | |
589 | } | |
590 | for (;;) { | |
591 | Authmethod *method = authmethod_get(authlist); | |
592 | if (method == NULL) | |
593 | fatal("Permission denied (%s).", authlist); | |
594 | authctxt->method = method; | |
595 | if (method->userauth(authctxt) != 0) { | |
596 | debug2("we sent a %s packet, wait for reply", method->name); | |
597 | break; | |
598 | } else { | |
599 | debug2("we did not send a packet, disable method"); | |
600 | method->enabled = NULL; | |
601 | } | |
602 | } | |
603 | } | |
604 | void | |
188adeb2 | 605 | input_userauth_error(int type, int plen, void *ctxt) |
606 | { | |
9616313f | 607 | fatal("input_userauth_error: bad message during authentication: " |
608 | "type %d", type); | |
609 | } | |
610 | void | |
611 | input_userauth_banner(int type, int plen, void *ctxt) | |
612 | { | |
613 | char *msg, *lang; | |
614 | debug3("input_userauth_banner"); | |
615 | msg = packet_get_string(NULL); | |
616 | lang = packet_get_string(NULL); | |
617 | fprintf(stderr, "%s", msg); | |
618 | xfree(msg); | |
619 | xfree(lang); | |
188adeb2 | 620 | } |
621 | void | |
622 | input_userauth_success(int type, int plen, void *ctxt) | |
623 | { | |
624 | Authctxt *authctxt = ctxt; | |
625 | if (authctxt == NULL) | |
626 | fatal("input_userauth_success: no authentication context"); | |
fee56204 | 627 | if (authctxt->authlist) |
628 | xfree(authctxt->authlist); | |
629 | clear_auth_state(authctxt); | |
188adeb2 | 630 | authctxt->success = 1; /* break out */ |
631 | } | |
632 | void | |
633 | input_userauth_failure(int type, int plen, void *ctxt) | |
634 | { | |
188adeb2 | 635 | Authctxt *authctxt = ctxt; |
636 | char *authlist = NULL; | |
637 | int partial; | |
188adeb2 | 638 | |
639 | if (authctxt == NULL) | |
640 | fatal("input_userauth_failure: no authentication context"); | |
641 | ||
94ec8c6b | 642 | authlist = packet_get_string(NULL); |
188adeb2 | 643 | partial = packet_get_char(); |
644 | packet_done(); | |
645 | ||
646 | if (partial != 0) | |
f72e01a5 | 647 | log("Authenticated with partial success."); |
188adeb2 | 648 | debug("authentications that can continue: %s", authlist); |
649 | ||
fee56204 | 650 | clear_auth_state(authctxt); |
651 | userauth(authctxt, authlist); | |
652 | } | |
653 | void | |
654 | input_userauth_pk_ok(int type, int plen, void *ctxt) | |
655 | { | |
656 | Authctxt *authctxt = ctxt; | |
657 | Key *key = NULL; | |
658 | Buffer b; | |
659 | int alen, blen, pktype, sent = 0; | |
660 | char *pkalg, *pkblob; | |
661 | ||
662 | if (authctxt == NULL) | |
663 | fatal("input_userauth_pk_ok: no authentication context"); | |
664 | if (datafellows & SSH_BUG_PKOK) { | |
665 | /* this is similar to SSH_BUG_PKAUTH */ | |
666 | debug2("input_userauth_pk_ok: SSH_BUG_PKOK"); | |
667 | pkblob = packet_get_string(&blen); | |
668 | buffer_init(&b); | |
669 | buffer_append(&b, pkblob, blen); | |
670 | pkalg = buffer_get_string(&b, &alen); | |
671 | buffer_free(&b); | |
672 | } else { | |
673 | pkalg = packet_get_string(&alen); | |
674 | pkblob = packet_get_string(&blen); | |
675 | } | |
676 | packet_done(); | |
677 | ||
678 | debug("input_userauth_pk_ok: pkalg %s blen %d lastkey %p hint %d", | |
679 | pkalg, blen, authctxt->last_key, authctxt->last_key_hint); | |
680 | ||
681 | do { | |
682 | if (authctxt->last_key == NULL || | |
683 | authctxt->last_key_sign == NULL) { | |
684 | debug("no last key or no sign cb"); | |
188adeb2 | 685 | break; |
188adeb2 | 686 | } |
fee56204 | 687 | debug2("last_key %s", key_fingerprint(authctxt->last_key)); |
688 | if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) { | |
689 | debug("unknown pkalg %s", pkalg); | |
690 | break; | |
691 | } | |
692 | if ((key = key_from_blob(pkblob, blen)) == NULL) { | |
693 | debug("no key from blob. pkalg %s", pkalg); | |
694 | break; | |
695 | } | |
696 | debug2("input_userauth_pk_ok: fp %s", key_fingerprint(key)); | |
697 | if (!key_equal(key, authctxt->last_key)) { | |
698 | debug("key != last_key"); | |
699 | break; | |
700 | } | |
701 | sent = sign_and_send_pubkey(authctxt, key, | |
702 | authctxt->last_key_sign); | |
703 | } while(0); | |
704 | ||
705 | if (key != NULL) | |
706 | key_free(key); | |
707 | xfree(pkalg); | |
708 | xfree(pkblob); | |
709 | ||
710 | /* unregister */ | |
711 | clear_auth_state(authctxt); | |
712 | dispatch_set(SSH2_MSG_USERAUTH_PK_OK, NULL); | |
713 | ||
714 | /* try another method if we did not send a packet*/ | |
715 | if (sent == 0) | |
716 | userauth(authctxt, NULL); | |
717 | ||
188adeb2 | 718 | } |
719 | ||
94ec8c6b | 720 | int |
721 | userauth_none(Authctxt *authctxt) | |
722 | { | |
723 | /* initial userauth request */ | |
724 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
725 | packet_put_cstring(authctxt->server_user); | |
726 | packet_put_cstring(authctxt->service); | |
727 | packet_put_cstring(authctxt->method->name); | |
728 | packet_send(); | |
94ec8c6b | 729 | return 1; |
730 | } | |
731 | ||
a306f2dd | 732 | int |
188adeb2 | 733 | userauth_passwd(Authctxt *authctxt) |
a306f2dd | 734 | { |
1d1ffb87 | 735 | static int attempt = 0; |
a306f2dd | 736 | char prompt[80]; |
737 | char *password; | |
738 | ||
fa649821 | 739 | if (attempt++ >= options.number_of_password_prompts) |
1d1ffb87 | 740 | return 0; |
741 | ||
fa649821 | 742 | if(attempt != 1) |
743 | error("Permission denied, please try again."); | |
744 | ||
f72e01a5 | 745 | snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ", |
188adeb2 | 746 | authctxt->server_user, authctxt->host); |
a306f2dd | 747 | password = read_passphrase(prompt, 0); |
748 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
188adeb2 | 749 | packet_put_cstring(authctxt->server_user); |
750 | packet_put_cstring(authctxt->service); | |
94ec8c6b | 751 | packet_put_cstring(authctxt->method->name); |
a306f2dd | 752 | packet_put_char(0); |
a6215e53 | 753 | packet_put_cstring(password); |
a306f2dd | 754 | memset(password, 0, strlen(password)); |
755 | xfree(password); | |
a6215e53 | 756 | packet_inject_ignore(64); |
a306f2dd | 757 | packet_send(); |
a306f2dd | 758 | return 1; |
759 | } | |
760 | ||
fee56204 | 761 | void |
762 | clear_auth_state(Authctxt *authctxt) | |
763 | { | |
764 | /* XXX clear authentication state */ | |
765 | if (authctxt->last_key != NULL && authctxt->last_key_hint == -1) { | |
766 | debug3("clear_auth_state: key_free %p", authctxt->last_key); | |
767 | key_free(authctxt->last_key); | |
768 | } | |
769 | authctxt->last_key = NULL; | |
770 | authctxt->last_key_hint = -2; | |
771 | authctxt->last_key_sign = NULL; | |
772 | } | |
773 | ||
2e73a022 | 774 | int |
188adeb2 | 775 | sign_and_send_pubkey(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback) |
a306f2dd | 776 | { |
777 | Buffer b; | |
1e3b8b07 | 778 | u_char *blob, *signature; |
a306f2dd | 779 | int bloblen, slen; |
74fc9186 | 780 | int skip = 0; |
2e73a022 | 781 | int ret = -1; |
94ec8c6b | 782 | int have_sig = 1; |
a306f2dd | 783 | |
cbc5abf9 | 784 | debug3("sign_and_send_pubkey"); |
fee56204 | 785 | |
fa08c86b | 786 | if (key_to_blob(k, &blob, &bloblen) == 0) { |
787 | /* we cannot handle this key */ | |
cbc5abf9 | 788 | debug3("sign_and_send_pubkey: cannot handle key"); |
fa08c86b | 789 | return 0; |
790 | } | |
a306f2dd | 791 | /* data to be signed */ |
792 | buffer_init(&b); | |
33de75a3 | 793 | if (datafellows & SSH_OLD_SESSIONID) { |
74fc9186 | 794 | buffer_append(&b, session_id2, session_id2_len); |
2b87da3b | 795 | skip = session_id2_len; |
33de75a3 | 796 | } else { |
797 | buffer_put_string(&b, session_id2, session_id2_len); | |
798 | skip = buffer_len(&b); | |
74fc9186 | 799 | } |
a306f2dd | 800 | buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); |
188adeb2 | 801 | buffer_put_cstring(&b, authctxt->server_user); |
d0c832f3 | 802 | buffer_put_cstring(&b, |
cbc5abf9 | 803 | datafellows & SSH_BUG_PKSERVICE ? |
d0c832f3 | 804 | "ssh-userauth" : |
188adeb2 | 805 | authctxt->service); |
cbc5abf9 | 806 | if (datafellows & SSH_BUG_PKAUTH) { |
807 | buffer_put_char(&b, have_sig); | |
808 | } else { | |
809 | buffer_put_cstring(&b, authctxt->method->name); | |
810 | buffer_put_char(&b, have_sig); | |
2b87da3b | 811 | buffer_put_cstring(&b, key_ssh_name(k)); |
cbc5abf9 | 812 | } |
a306f2dd | 813 | buffer_put_string(&b, blob, bloblen); |
a306f2dd | 814 | |
815 | /* generate signature */ | |
fee56204 | 816 | ret = (*sign_callback)(authctxt, k, &signature, &slen, |
817 | buffer_ptr(&b), buffer_len(&b)); | |
2e73a022 | 818 | if (ret == -1) { |
819 | xfree(blob); | |
820 | buffer_free(&b); | |
821 | return 0; | |
822 | } | |
fa08c86b | 823 | #ifdef DEBUG_PK |
a306f2dd | 824 | buffer_dump(&b); |
825 | #endif | |
cbc5abf9 | 826 | if (datafellows & SSH_BUG_PKSERVICE) { |
d0c832f3 | 827 | buffer_clear(&b); |
828 | buffer_append(&b, session_id2, session_id2_len); | |
fee56204 | 829 | skip = session_id2_len; |
d0c832f3 | 830 | buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); |
188adeb2 | 831 | buffer_put_cstring(&b, authctxt->server_user); |
832 | buffer_put_cstring(&b, authctxt->service); | |
94ec8c6b | 833 | buffer_put_cstring(&b, authctxt->method->name); |
834 | buffer_put_char(&b, have_sig); | |
cbc5abf9 | 835 | if (!(datafellows & SSH_BUG_PKAUTH)) |
2b87da3b | 836 | buffer_put_cstring(&b, key_ssh_name(k)); |
d0c832f3 | 837 | buffer_put_string(&b, blob, bloblen); |
838 | } | |
839 | xfree(blob); | |
fee56204 | 840 | |
a306f2dd | 841 | /* append signature */ |
842 | buffer_put_string(&b, signature, slen); | |
843 | xfree(signature); | |
844 | ||
845 | /* skip session id and packet type */ | |
74fc9186 | 846 | if (buffer_len(&b) < skip + 1) |
188adeb2 | 847 | fatal("userauth_pubkey: internal error"); |
74fc9186 | 848 | buffer_consume(&b, skip + 1); |
a306f2dd | 849 | |
850 | /* put remaining data from buffer into packet */ | |
851 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
852 | packet_put_raw(buffer_ptr(&b), buffer_len(&b)); | |
853 | buffer_free(&b); | |
a306f2dd | 854 | packet_send(); |
2e73a022 | 855 | |
856 | return 1; | |
4c8722d9 | 857 | } |
858 | ||
859 | int | |
fee56204 | 860 | send_pubkey_test(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback, |
861 | int hint) | |
4c8722d9 | 862 | { |
fee56204 | 863 | u_char *blob; |
864 | int bloblen, have_sig = 0; | |
4c8722d9 | 865 | |
fee56204 | 866 | debug3("send_pubkey_test"); |
867 | ||
868 | if (key_to_blob(k, &blob, &bloblen) == 0) { | |
869 | /* we cannot handle this key */ | |
870 | debug3("send_pubkey_test: cannot handle key"); | |
4c8722d9 | 871 | return 0; |
872 | } | |
fee56204 | 873 | /* register callback for USERAUTH_PK_OK message */ |
874 | authctxt->last_key_sign = sign_callback; | |
875 | authctxt->last_key_hint = hint; | |
876 | authctxt->last_key = k; | |
877 | dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok); | |
4c8722d9 | 878 | |
fee56204 | 879 | packet_start(SSH2_MSG_USERAUTH_REQUEST); |
880 | packet_put_cstring(authctxt->server_user); | |
881 | packet_put_cstring(authctxt->service); | |
882 | packet_put_cstring(authctxt->method->name); | |
883 | packet_put_char(have_sig); | |
884 | if (!(datafellows & SSH_BUG_PKAUTH)) | |
885 | packet_put_cstring(key_ssh_name(k)); | |
886 | packet_put_string(blob, bloblen); | |
887 | xfree(blob); | |
888 | packet_send(); | |
889 | return 1; | |
890 | } | |
891 | ||
892 | Key * | |
893 | load_identity_file(char *filename) | |
894 | { | |
895 | Key *private; | |
896 | char prompt[300], *passphrase; | |
897 | int success = 0, quit, i; | |
898 | ||
899 | private = key_new(KEY_UNSPEC); | |
900 | if (!load_private_key(filename, "", private, NULL)) { | |
f72e01a5 | 901 | if (options.batch_mode) { |
fee56204 | 902 | key_free(private); |
903 | return NULL; | |
f72e01a5 | 904 | } |
4c8722d9 | 905 | snprintf(prompt, sizeof prompt, |
fa08c86b | 906 | "Enter passphrase for key '%.100s': ", filename); |
188adeb2 | 907 | for (i = 0; i < options.number_of_password_prompts; i++) { |
908 | passphrase = read_passphrase(prompt, 0); | |
909 | if (strcmp(passphrase, "") != 0) { | |
fee56204 | 910 | success = load_private_key(filename, |
911 | passphrase, private, NULL); | |
912 | quit = 0; | |
188adeb2 | 913 | } else { |
914 | debug2("no passphrase given, try next key"); | |
fee56204 | 915 | quit = 1; |
188adeb2 | 916 | } |
917 | memset(passphrase, 0, strlen(passphrase)); | |
918 | xfree(passphrase); | |
fee56204 | 919 | if (success || quit) |
188adeb2 | 920 | break; |
921 | debug2("bad passphrase given, try again..."); | |
922 | } | |
4c8722d9 | 923 | if (!success) { |
fee56204 | 924 | key_free(private); |
925 | return NULL; | |
4c8722d9 | 926 | } |
927 | } | |
fee56204 | 928 | return private; |
929 | } | |
930 | ||
931 | int | |
932 | identity_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp, | |
933 | u_char *data, int datalen) | |
934 | { | |
935 | Key *private; | |
936 | int idx, ret; | |
937 | ||
938 | idx = authctxt->last_key_hint; | |
939 | if (idx < 0) | |
940 | return -1; | |
941 | private = load_identity_file(options.identity_files[idx]); | |
942 | if (private == NULL) | |
943 | return -1; | |
944 | ret = key_sign(private, sigp, lenp, data, datalen); | |
945 | key_free(private); | |
2e73a022 | 946 | return ret; |
947 | } | |
948 | ||
1e3b8b07 | 949 | int agent_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp, |
950 | u_char *data, int datalen) | |
2e73a022 | 951 | { |
188adeb2 | 952 | return ssh_agent_sign(authctxt->agent, key, sigp, lenp, data, datalen); |
2e73a022 | 953 | } |
954 | ||
fee56204 | 955 | int key_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp, |
956 | u_char *data, int datalen) | |
957 | { | |
958 | return key_sign(key, sigp, lenp, data, datalen); | |
959 | } | |
960 | ||
2e73a022 | 961 | int |
188adeb2 | 962 | userauth_pubkey_agent(Authctxt *authctxt) |
2e73a022 | 963 | { |
964 | static int called = 0; | |
fa08c86b | 965 | int ret = 0; |
2e73a022 | 966 | char *comment; |
967 | Key *k; | |
2e73a022 | 968 | |
969 | if (called == 0) { | |
fa08c86b | 970 | if (ssh_get_num_identities(authctxt->agent, 2) == 0) |
971 | debug2("userauth_pubkey_agent: no keys at all"); | |
188adeb2 | 972 | called = 1; |
2e73a022 | 973 | } |
fa08c86b | 974 | k = ssh_get_next_identity(authctxt->agent, &comment, 2); |
188adeb2 | 975 | if (k == NULL) { |
fa08c86b | 976 | debug2("userauth_pubkey_agent: no more keys"); |
977 | } else { | |
fee56204 | 978 | debug("userauth_pubkey_agent: testing agent key %s", comment); |
fa08c86b | 979 | xfree(comment); |
fee56204 | 980 | ret = send_pubkey_test(authctxt, k, agent_sign_cb, -1); |
981 | if (ret == 0) | |
982 | key_free(k); | |
188adeb2 | 983 | } |
fa08c86b | 984 | if (ret == 0) |
985 | debug2("userauth_pubkey_agent: no message sent"); | |
2e73a022 | 986 | return ret; |
a306f2dd | 987 | } |
988 | ||
188adeb2 | 989 | int |
990 | userauth_pubkey(Authctxt *authctxt) | |
a306f2dd | 991 | { |
188adeb2 | 992 | static int idx = 0; |
993 | int sent = 0; | |
fee56204 | 994 | Key *key; |
995 | char *filename; | |
188adeb2 | 996 | |
fa08c86b | 997 | if (authctxt->agent != NULL) { |
998 | do { | |
999 | sent = userauth_pubkey_agent(authctxt); | |
1000 | } while(!sent && authctxt->agent->howmany > 0); | |
1001 | } | |
1002 | while (!sent && idx < options.num_identity_files) { | |
fee56204 | 1003 | key = options.identity_keys[idx]; |
1004 | filename = options.identity_files[idx]; | |
1005 | if (key == NULL) { | |
1006 | debug("try privkey: %s", filename); | |
1007 | key = load_identity_file(filename); | |
1008 | if (key != NULL) { | |
1009 | sent = sign_and_send_pubkey(authctxt, key, | |
1010 | key_sign_cb); | |
1011 | key_free(key); | |
1012 | } | |
1013 | } else if (key->type != KEY_RSA1) { | |
1014 | debug("try pubkey: %s", filename); | |
1015 | sent = send_pubkey_test(authctxt, key, | |
1016 | identity_sign_cb, idx); | |
1017 | } | |
fa08c86b | 1018 | idx++; |
1019 | } | |
188adeb2 | 1020 | return sent; |
1021 | } | |
a306f2dd | 1022 | |
94ec8c6b | 1023 | /* |
1024 | * Send userauth request message specifying keyboard-interactive method. | |
1025 | */ | |
1026 | int | |
1027 | userauth_kbdint(Authctxt *authctxt) | |
1028 | { | |
1029 | static int attempt = 0; | |
1030 | ||
1031 | if (attempt++ >= options.number_of_password_prompts) | |
1032 | return 0; | |
1033 | ||
1034 | debug2("userauth_kbdint"); | |
1035 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
1036 | packet_put_cstring(authctxt->server_user); | |
1037 | packet_put_cstring(authctxt->service); | |
1038 | packet_put_cstring(authctxt->method->name); | |
1039 | packet_put_cstring(""); /* lang */ | |
1040 | packet_put_cstring(options.kbd_interactive_devices ? | |
1041 | options.kbd_interactive_devices : ""); | |
1042 | packet_send(); | |
94ec8c6b | 1043 | |
1044 | dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req); | |
1045 | return 1; | |
1046 | } | |
1047 | ||
1048 | /* | |
f72e01a5 | 1049 | * parse INFO_REQUEST, prompt user and send INFO_RESPONSE |
94ec8c6b | 1050 | */ |
1051 | void | |
1052 | input_userauth_info_req(int type, int plen, void *ctxt) | |
1053 | { | |
1054 | Authctxt *authctxt = ctxt; | |
f72e01a5 | 1055 | char *name, *inst, *lang, *prompt, *response; |
1e3b8b07 | 1056 | u_int num_prompts, i; |
94ec8c6b | 1057 | int echo = 0; |
1058 | ||
1059 | debug2("input_userauth_info_req"); | |
1060 | ||
1061 | if (authctxt == NULL) | |
1062 | fatal("input_userauth_info_req: no authentication context"); | |
1063 | ||
1064 | name = packet_get_string(NULL); | |
1065 | inst = packet_get_string(NULL); | |
1066 | lang = packet_get_string(NULL); | |
94ec8c6b | 1067 | if (strlen(name) > 0) |
1068 | cli_mesg(name); | |
94ec8c6b | 1069 | if (strlen(inst) > 0) |
1070 | cli_mesg(inst); | |
f72e01a5 | 1071 | xfree(name); |
94ec8c6b | 1072 | xfree(inst); |
f72e01a5 | 1073 | xfree(lang); |
94ec8c6b | 1074 | |
1075 | num_prompts = packet_get_int(); | |
1076 | /* | |
1077 | * Begin to build info response packet based on prompts requested. | |
1078 | * We commit to providing the correct number of responses, so if | |
1079 | * further on we run into a problem that prevents this, we have to | |
1080 | * be sure and clean this up and send a correct error response. | |
1081 | */ | |
1082 | packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE); | |
1083 | packet_put_int(num_prompts); | |
1084 | ||
1085 | for (i = 0; i < num_prompts; i++) { | |
1086 | prompt = packet_get_string(NULL); | |
1087 | echo = packet_get_char(); | |
1088 | ||
1089 | response = cli_prompt(prompt, echo); | |
1090 | ||
a6215e53 | 1091 | packet_put_cstring(response); |
94ec8c6b | 1092 | memset(response, 0, strlen(response)); |
1093 | xfree(response); | |
1094 | xfree(prompt); | |
1095 | } | |
1096 | packet_done(); /* done with parsing incoming message. */ | |
1097 | ||
a6215e53 | 1098 | packet_inject_ignore(64); |
94ec8c6b | 1099 | packet_send(); |
94ec8c6b | 1100 | } |
a306f2dd | 1101 | |
188adeb2 | 1102 | /* find auth method */ |
1103 | ||
1104 | #define DELIM "," | |
1105 | ||
1106 | static char *def_authlist = "publickey,password"; | |
1107 | static char *authlist_current = NULL; /* clean copy used for comparison */ | |
1108 | static char *authname_current = NULL; /* last used auth method */ | |
1109 | static char *authlist_working = NULL; /* copy that gets modified by strtok_r() */ | |
1110 | static char *authlist_state = NULL; /* state variable for strtok_r() */ | |
1111 | ||
1112 | /* | |
1113 | * Before starting to use a new authentication method list sent by the | |
1114 | * server, reset internal variables. This should also be called when | |
1115 | * finished processing server list to free resources. | |
1116 | */ | |
1117 | void | |
1e3b8b07 | 1118 | authmethod_clear(void) |
188adeb2 | 1119 | { |
1120 | if (authlist_current != NULL) { | |
1121 | xfree(authlist_current); | |
1122 | authlist_current = NULL; | |
a306f2dd | 1123 | } |
188adeb2 | 1124 | if (authlist_working != NULL) { |
1125 | xfree(authlist_working); | |
1126 | authlist_working = NULL; | |
a306f2dd | 1127 | } |
188adeb2 | 1128 | if (authname_current != NULL) { |
1129 | xfree(authname_current); | |
f72e01a5 | 1130 | authname_current = NULL; |
188adeb2 | 1131 | } |
1132 | if (authlist_state != NULL) | |
1133 | authlist_state = NULL; | |
1134 | return; | |
1135 | } | |
a306f2dd | 1136 | |
188adeb2 | 1137 | /* |
1138 | * given auth method name, if configurable options permit this method fill | |
1139 | * in auth_ident field and return true, otherwise return false. | |
1140 | */ | |
1141 | int | |
1142 | authmethod_is_enabled(Authmethod *method) | |
1143 | { | |
1144 | if (method == NULL) | |
1145 | return 0; | |
1146 | /* return false if options indicate this method is disabled */ | |
1147 | if (method->enabled == NULL || *method->enabled == 0) | |
1148 | return 0; | |
1149 | /* return false if batch mode is enabled but method needs interactive mode */ | |
1150 | if (method->batch_flag != NULL && *method->batch_flag != 0) | |
1151 | return 0; | |
1152 | return 1; | |
1153 | } | |
a306f2dd | 1154 | |
188adeb2 | 1155 | Authmethod * |
1156 | authmethod_lookup(const char *name) | |
1157 | { | |
1158 | Authmethod *method = NULL; | |
1159 | if (name != NULL) | |
1160 | for (method = authmethods; method->name != NULL; method++) | |
1161 | if (strcmp(name, method->name) == 0) | |
1162 | return method; | |
1163 | debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); | |
1164 | return NULL; | |
1165 | } | |
1166 | ||
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, | |
1170 | * use a built-in default list. If the server sends a nil list after | |
1171 | * previously sending a valid list, continue using the list originally | |
1172 | * sent. | |
2b87da3b | 1173 | */ |
188adeb2 | 1174 | |
1175 | Authmethod * | |
1176 | authmethod_get(char *authlist) | |
1177 | { | |
a22aff1f | 1178 | char *name = NULL, *authname_old; |
188adeb2 | 1179 | Authmethod *method = NULL; |
2b87da3b | 1180 | |
188adeb2 | 1181 | /* Use a suitable default if we're passed a nil list. */ |
1182 | if (authlist == NULL || strlen(authlist) == 0) | |
1183 | authlist = def_authlist; | |
1184 | ||
1185 | if (authlist_current == NULL || strcmp(authlist, authlist_current) != 0) { | |
1186 | /* start over if passed a different list */ | |
94ec8c6b | 1187 | debug3("start over, passed a different list"); |
188adeb2 | 1188 | authmethod_clear(); |
1189 | authlist_current = xstrdup(authlist); | |
1190 | authlist_working = xstrdup(authlist); | |
1191 | name = strtok_r(authlist_working, DELIM, &authlist_state); | |
1192 | } else { | |
1193 | /* | |
1194 | * try to use previously used authentication method | |
1195 | * or continue to use previously passed list | |
1196 | */ | |
1197 | name = (authname_current != NULL) ? | |
1198 | authname_current : strtok_r(NULL, DELIM, &authlist_state); | |
1199 | } | |
1200 | ||
1201 | while (name != NULL) { | |
94ec8c6b | 1202 | debug3("authmethod_lookup %s", name); |
188adeb2 | 1203 | method = authmethod_lookup(name); |
94ec8c6b | 1204 | if (method != NULL && authmethod_is_enabled(method)) { |
1205 | debug3("authmethod_is_enabled %s", name); | |
a306f2dd | 1206 | break; |
94ec8c6b | 1207 | } |
188adeb2 | 1208 | name = strtok_r(NULL, DELIM, &authlist_state); |
94ec8c6b | 1209 | method = NULL; |
188adeb2 | 1210 | } |
1211 | ||
a22aff1f | 1212 | authname_old = authname_current; |
94ec8c6b | 1213 | if (method != NULL) { |
188adeb2 | 1214 | debug("next auth method to try is %s", name); |
1215 | authname_current = xstrdup(name); | |
188adeb2 | 1216 | } else { |
1217 | debug("no more auth methods to try"); | |
1218 | authname_current = NULL; | |
a306f2dd | 1219 | } |
a22aff1f | 1220 | |
1221 | if (authname_old != NULL) | |
1222 | xfree(authname_old); | |
1223 | ||
1224 | return (method); | |
a306f2dd | 1225 | } |