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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" | |
aeaa3d9e | 26 | RCSID("$OpenBSD: sshconnect2.c,v 1.56 2001/03/26 08:07:09 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 | |
80cd07ae | 99 | myproposal[PROPOSAL_ENC_ALGS_STOC] = |
100 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); | |
101 | ||
94ec8c6b | 102 | /* buffers with raw kexinit messages */ |
103 | server_kexinit = xmalloc(sizeof(*server_kexinit)); | |
104 | buffer_init(server_kexinit); | |
105 | client_kexinit = kex_init(myproposal); | |
106 | ||
107 | /* algorithm negotiation */ | |
108 | kex_exchange_kexinit(client_kexinit, server_kexinit, sprop); | |
109 | kex = kex_choose_conf(myproposal, sprop, 0); | |
110 | for (i = 0; i < PROPOSAL_MAX; i++) | |
111 | xfree(sprop[i]); | |
112 | ||
113 | /* server authentication and session key agreement */ | |
114 | switch(kex->kex_type) { | |
115 | case DH_GRP1_SHA1: | |
116 | ssh_dh1_client(kex, host, hostaddr, | |
117 | client_kexinit, server_kexinit); | |
118 | break; | |
119 | case DH_GEX_SHA1: | |
120 | ssh_dhgex_client(kex, host, hostaddr, client_kexinit, | |
121 | server_kexinit); | |
122 | break; | |
123 | default: | |
124 | fatal("Unsupported key exchange %d", kex->kex_type); | |
125 | } | |
126 | ||
127 | buffer_free(client_kexinit); | |
128 | buffer_free(server_kexinit); | |
129 | xfree(client_kexinit); | |
130 | xfree(server_kexinit); | |
131 | ||
132 | debug("Wait SSH2_MSG_NEWKEYS."); | |
133 | packet_read_expect(&plen, SSH2_MSG_NEWKEYS); | |
134 | packet_done(); | |
135 | debug("GOT SSH2_MSG_NEWKEYS."); | |
136 | ||
137 | debug("send SSH2_MSG_NEWKEYS."); | |
138 | packet_start(SSH2_MSG_NEWKEYS); | |
139 | packet_send(); | |
140 | packet_write_wait(); | |
141 | debug("done: send SSH2_MSG_NEWKEYS."); | |
142 | ||
143 | #ifdef DEBUG_KEXDH | |
144 | /* send 1st encrypted/maced/compressed message */ | |
145 | packet_start(SSH2_MSG_IGNORE); | |
146 | packet_put_cstring("markus"); | |
147 | packet_send(); | |
148 | packet_write_wait(); | |
149 | #endif | |
150 | debug("done: KEX2."); | |
151 | } | |
152 | ||
153 | /* diffie-hellman-group1-sha1 */ | |
154 | ||
155 | void | |
2b87da3b | 156 | ssh_dh1_client(Kex *kex, char *host, struct sockaddr *hostaddr, |
94ec8c6b | 157 | Buffer *client_kexinit, Buffer *server_kexinit) |
a306f2dd | 158 | { |
188adeb2 | 159 | #ifdef DEBUG_KEXDH |
160 | int i; | |
161 | #endif | |
71276795 | 162 | int plen, dlen; |
1e3b8b07 | 163 | u_int klen, kout; |
a306f2dd | 164 | char *signature = NULL; |
1e3b8b07 | 165 | u_int slen; |
a306f2dd | 166 | char *server_host_key_blob = NULL; |
167 | Key *server_host_key; | |
1e3b8b07 | 168 | u_int sbloblen; |
a306f2dd | 169 | DH *dh; |
170 | BIGNUM *dh_server_pub = 0; | |
171 | BIGNUM *shared_secret = 0; | |
1e3b8b07 | 172 | u_char *kbuf; |
173 | u_char *hash; | |
a306f2dd | 174 | |
a306f2dd | 175 | debug("Sending SSH2_MSG_KEXDH_INIT."); |
a306f2dd | 176 | /* generate and send 'e', client DH public key */ |
177 | dh = dh_new_group1(); | |
7de5b06b | 178 | dh_gen_key(dh, kex->we_need * 8); |
a306f2dd | 179 | packet_start(SSH2_MSG_KEXDH_INIT); |
180 | packet_put_bignum2(dh->pub_key); | |
181 | packet_send(); | |
182 | packet_write_wait(); | |
183 | ||
184 | #ifdef DEBUG_KEXDH | |
185 | fprintf(stderr, "\np= "); | |
188adeb2 | 186 | BN_print_fp(stderr, dh->p); |
a306f2dd | 187 | fprintf(stderr, "\ng= "); |
188adeb2 | 188 | BN_print_fp(stderr, dh->g); |
a306f2dd | 189 | fprintf(stderr, "\npub= "); |
188adeb2 | 190 | BN_print_fp(stderr, dh->pub_key); |
a306f2dd | 191 | fprintf(stderr, "\n"); |
192 | DHparams_print_fp(stderr, dh); | |
193 | #endif | |
194 | ||
195 | debug("Wait SSH2_MSG_KEXDH_REPLY."); | |
196 | ||
71276795 | 197 | packet_read_expect(&plen, SSH2_MSG_KEXDH_REPLY); |
a306f2dd | 198 | |
199 | debug("Got SSH2_MSG_KEXDH_REPLY."); | |
200 | ||
201 | /* key, cert */ | |
202 | server_host_key_blob = packet_get_string(&sbloblen); | |
fa08c86b | 203 | server_host_key = key_from_blob(server_host_key_blob, sbloblen); |
a306f2dd | 204 | if (server_host_key == NULL) |
205 | fatal("cannot decode server_host_key_blob"); | |
206 | ||
207 | check_host_key(host, hostaddr, server_host_key, | |
94ec8c6b | 208 | options.user_hostfile2, options.system_hostfile2); |
a306f2dd | 209 | |
210 | /* DH paramter f, server public DH key */ | |
211 | dh_server_pub = BN_new(); | |
212 | if (dh_server_pub == NULL) | |
213 | fatal("dh_server_pub == NULL"); | |
214 | packet_get_bignum2(dh_server_pub, &dlen); | |
215 | ||
216 | #ifdef DEBUG_KEXDH | |
217 | fprintf(stderr, "\ndh_server_pub= "); | |
188adeb2 | 218 | BN_print_fp(stderr, dh_server_pub); |
a306f2dd | 219 | fprintf(stderr, "\n"); |
220 | debug("bits %d", BN_num_bits(dh_server_pub)); | |
221 | #endif | |
222 | ||
223 | /* signed H */ | |
224 | signature = packet_get_string(&slen); | |
225 | packet_done(); | |
226 | ||
227 | if (!dh_pub_is_valid(dh, dh_server_pub)) | |
228 | packet_disconnect("bad server public DH value"); | |
229 | ||
230 | klen = DH_size(dh); | |
231 | kbuf = xmalloc(klen); | |
232 | kout = DH_compute_key(kbuf, dh_server_pub, dh); | |
233 | #ifdef DEBUG_KEXDH | |
234 | debug("shared secret: len %d/%d", klen, kout); | |
235 | fprintf(stderr, "shared secret == "); | |
236 | for (i = 0; i< kout; i++) | |
237 | fprintf(stderr, "%02x", (kbuf[i])&0xff); | |
238 | fprintf(stderr, "\n"); | |
239 | #endif | |
240 | shared_secret = BN_new(); | |
241 | ||
242 | BN_bin2bn(kbuf, kout, shared_secret); | |
243 | memset(kbuf, 0, klen); | |
244 | xfree(kbuf); | |
245 | ||
246 | /* calc and verify H */ | |
247 | hash = kex_hash( | |
248 | client_version_string, | |
249 | server_version_string, | |
250 | buffer_ptr(client_kexinit), buffer_len(client_kexinit), | |
251 | buffer_ptr(server_kexinit), buffer_len(server_kexinit), | |
252 | server_host_key_blob, sbloblen, | |
253 | dh->pub_key, | |
254 | dh_server_pub, | |
255 | shared_secret | |
256 | ); | |
257 | xfree(server_host_key_blob); | |
71276795 | 258 | DH_free(dh); |
53a24016 | 259 | BN_free(dh_server_pub); |
a306f2dd | 260 | #ifdef DEBUG_KEXDH |
261 | fprintf(stderr, "hash == "); | |
262 | for (i = 0; i< 20; i++) | |
263 | fprintf(stderr, "%02x", (hash[i])&0xff); | |
264 | fprintf(stderr, "\n"); | |
265 | #endif | |
1e3b8b07 | 266 | if (key_verify(server_host_key, (u_char *)signature, slen, hash, 20) != 1) |
fa08c86b | 267 | fatal("key_verify failed for server_host_key"); |
a306f2dd | 268 | key_free(server_host_key); |
53a24016 | 269 | xfree(signature); |
a306f2dd | 270 | |
271 | kex_derive_keys(kex, hash, shared_secret); | |
53a24016 | 272 | BN_clear_free(shared_secret); |
a306f2dd | 273 | packet_set_kex(kex); |
274 | ||
a306f2dd | 275 | /* save session id */ |
276 | session_id2_len = 20; | |
277 | session_id2 = xmalloc(session_id2_len); | |
278 | memcpy(session_id2, hash, session_id2_len); | |
71276795 | 279 | } |
280 | ||
94ec8c6b | 281 | /* diffie-hellman-group-exchange-sha1 */ |
282 | ||
283 | /* | |
284 | * Estimates the group order for a Diffie-Hellman group that has an | |
285 | * attack complexity approximately the same as O(2**bits). Estimate | |
286 | * with: O(exp(1.9223 * (ln q)^(1/3) (ln ln q)^(2/3))) | |
287 | */ | |
288 | ||
289 | int | |
290 | dh_estimate(int bits) | |
291 | { | |
2b87da3b | 292 | |
94ec8c6b | 293 | if (bits < 64) |
294 | return (512); /* O(2**63) */ | |
295 | if (bits < 128) | |
296 | return (1024); /* O(2**86) */ | |
297 | if (bits < 192) | |
298 | return (2048); /* O(2**116) */ | |
299 | return (4096); /* O(2**156) */ | |
300 | } | |
301 | ||
71276795 | 302 | void |
94ec8c6b | 303 | ssh_dhgex_client(Kex *kex, char *host, struct sockaddr *hostaddr, |
304 | Buffer *client_kexinit, Buffer *server_kexinit) | |
71276795 | 305 | { |
94ec8c6b | 306 | #ifdef DEBUG_KEXDH |
307 | int i; | |
308 | #endif | |
309 | int plen, dlen; | |
1e3b8b07 | 310 | u_int klen, kout; |
94ec8c6b | 311 | char *signature = NULL; |
1e3b8b07 | 312 | u_int slen, nbits; |
94ec8c6b | 313 | char *server_host_key_blob = NULL; |
314 | Key *server_host_key; | |
1e3b8b07 | 315 | u_int sbloblen; |
94ec8c6b | 316 | DH *dh; |
317 | BIGNUM *dh_server_pub = 0; | |
318 | BIGNUM *shared_secret = 0; | |
319 | BIGNUM *p = 0, *g = 0; | |
1e3b8b07 | 320 | u_char *kbuf; |
321 | u_char *hash; | |
71276795 | 322 | |
7de5b06b | 323 | nbits = dh_estimate(kex->we_need * 8); |
71276795 | 324 | |
94ec8c6b | 325 | debug("Sending SSH2_MSG_KEX_DH_GEX_REQUEST."); |
326 | packet_start(SSH2_MSG_KEX_DH_GEX_REQUEST); | |
327 | packet_put_int(nbits); | |
328 | packet_send(); | |
329 | packet_write_wait(); | |
71276795 | 330 | |
94ec8c6b | 331 | #ifdef DEBUG_KEXDH |
332 | fprintf(stderr, "\nnbits = %d", nbits); | |
333 | #endif | |
71276795 | 334 | |
94ec8c6b | 335 | debug("Wait SSH2_MSG_KEX_DH_GEX_GROUP."); |
71276795 | 336 | |
94ec8c6b | 337 | packet_read_expect(&plen, SSH2_MSG_KEX_DH_GEX_GROUP); |
a306f2dd | 338 | |
94ec8c6b | 339 | debug("Got SSH2_MSG_KEX_DH_GEX_GROUP."); |
a306f2dd | 340 | |
94ec8c6b | 341 | if ((p = BN_new()) == NULL) |
342 | fatal("BN_new"); | |
343 | packet_get_bignum2(p, &dlen); | |
344 | if ((g = BN_new()) == NULL) | |
345 | fatal("BN_new"); | |
346 | packet_get_bignum2(g, &dlen); | |
42f11eb2 | 347 | dh = dh_new_group(g, p); |
a306f2dd | 348 | |
7de5b06b | 349 | dh_gen_key(dh, kex->we_need * 8); |
3e1caa83 | 350 | |
a306f2dd | 351 | #ifdef DEBUG_KEXDH |
94ec8c6b | 352 | fprintf(stderr, "\np= "); |
353 | BN_print_fp(stderr, dh->p); | |
354 | fprintf(stderr, "\ng= "); | |
355 | BN_print_fp(stderr, dh->g); | |
356 | fprintf(stderr, "\npub= "); | |
357 | BN_print_fp(stderr, dh->pub_key); | |
358 | fprintf(stderr, "\n"); | |
359 | DHparams_print_fp(stderr, dh); | |
360 | #endif | |
361 | ||
362 | debug("Sending SSH2_MSG_KEX_DH_GEX_INIT."); | |
363 | /* generate and send 'e', client DH public key */ | |
364 | packet_start(SSH2_MSG_KEX_DH_GEX_INIT); | |
365 | packet_put_bignum2(dh->pub_key); | |
a306f2dd | 366 | packet_send(); |
367 | packet_write_wait(); | |
94ec8c6b | 368 | |
369 | debug("Wait SSH2_MSG_KEX_DH_GEX_REPLY."); | |
370 | ||
371 | packet_read_expect(&plen, SSH2_MSG_KEX_DH_GEX_REPLY); | |
372 | ||
373 | debug("Got SSH2_MSG_KEXDH_REPLY."); | |
374 | ||
375 | /* key, cert */ | |
376 | server_host_key_blob = packet_get_string(&sbloblen); | |
fa08c86b | 377 | server_host_key = key_from_blob(server_host_key_blob, sbloblen); |
94ec8c6b | 378 | if (server_host_key == NULL) |
379 | fatal("cannot decode server_host_key_blob"); | |
380 | ||
381 | check_host_key(host, hostaddr, server_host_key, | |
382 | options.user_hostfile2, options.system_hostfile2); | |
383 | ||
384 | /* DH paramter f, server public DH key */ | |
385 | dh_server_pub = BN_new(); | |
386 | if (dh_server_pub == NULL) | |
387 | fatal("dh_server_pub == NULL"); | |
388 | packet_get_bignum2(dh_server_pub, &dlen); | |
389 | ||
390 | #ifdef DEBUG_KEXDH | |
391 | fprintf(stderr, "\ndh_server_pub= "); | |
392 | BN_print_fp(stderr, dh_server_pub); | |
393 | fprintf(stderr, "\n"); | |
394 | debug("bits %d", BN_num_bits(dh_server_pub)); | |
a306f2dd | 395 | #endif |
94ec8c6b | 396 | |
397 | /* signed H */ | |
398 | signature = packet_get_string(&slen); | |
399 | packet_done(); | |
400 | ||
401 | if (!dh_pub_is_valid(dh, dh_server_pub)) | |
402 | packet_disconnect("bad server public DH value"); | |
403 | ||
404 | klen = DH_size(dh); | |
405 | kbuf = xmalloc(klen); | |
406 | kout = DH_compute_key(kbuf, dh_server_pub, dh); | |
407 | #ifdef DEBUG_KEXDH | |
408 | debug("shared secret: len %d/%d", klen, kout); | |
409 | fprintf(stderr, "shared secret == "); | |
410 | for (i = 0; i< kout; i++) | |
411 | fprintf(stderr, "%02x", (kbuf[i])&0xff); | |
412 | fprintf(stderr, "\n"); | |
413 | #endif | |
414 | shared_secret = BN_new(); | |
415 | ||
416 | BN_bin2bn(kbuf, kout, shared_secret); | |
417 | memset(kbuf, 0, klen); | |
418 | xfree(kbuf); | |
419 | ||
420 | /* calc and verify H */ | |
421 | hash = kex_hash_gex( | |
422 | client_version_string, | |
423 | server_version_string, | |
424 | buffer_ptr(client_kexinit), buffer_len(client_kexinit), | |
425 | buffer_ptr(server_kexinit), buffer_len(server_kexinit), | |
426 | server_host_key_blob, sbloblen, | |
2b87da3b | 427 | nbits, dh->p, dh->g, |
94ec8c6b | 428 | dh->pub_key, |
429 | dh_server_pub, | |
430 | shared_secret | |
431 | ); | |
432 | xfree(server_host_key_blob); | |
433 | DH_free(dh); | |
53a24016 | 434 | BN_free(dh_server_pub); |
94ec8c6b | 435 | #ifdef DEBUG_KEXDH |
436 | fprintf(stderr, "hash == "); | |
437 | for (i = 0; i< 20; i++) | |
438 | fprintf(stderr, "%02x", (hash[i])&0xff); | |
439 | fprintf(stderr, "\n"); | |
440 | #endif | |
1e3b8b07 | 441 | if (key_verify(server_host_key, (u_char *)signature, slen, hash, 20) != 1) |
fa08c86b | 442 | fatal("key_verify failed for server_host_key"); |
94ec8c6b | 443 | key_free(server_host_key); |
53a24016 | 444 | xfree(signature); |
94ec8c6b | 445 | |
446 | kex_derive_keys(kex, hash, shared_secret); | |
53a24016 | 447 | BN_clear_free(shared_secret); |
94ec8c6b | 448 | packet_set_kex(kex); |
449 | ||
450 | /* save session id */ | |
451 | session_id2_len = 20; | |
452 | session_id2 = xmalloc(session_id2_len); | |
453 | memcpy(session_id2, hash, session_id2_len); | |
a306f2dd | 454 | } |
71276795 | 455 | |
a306f2dd | 456 | /* |
457 | * Authenticate user | |
458 | */ | |
188adeb2 | 459 | |
460 | typedef struct Authctxt Authctxt; | |
461 | typedef struct Authmethod Authmethod; | |
462 | ||
463 | typedef int sign_cb_fn( | |
464 | Authctxt *authctxt, Key *key, | |
1e3b8b07 | 465 | u_char **sigp, int *lenp, u_char *data, int datalen); |
188adeb2 | 466 | |
467 | struct Authctxt { | |
468 | const char *server_user; | |
469 | const char *host; | |
470 | const char *service; | |
471 | AuthenticationConnection *agent; | |
188adeb2 | 472 | Authmethod *method; |
94ec8c6b | 473 | int success; |
fee56204 | 474 | char *authlist; |
475 | Key *last_key; | |
476 | sign_cb_fn *last_key_sign; | |
477 | int last_key_hint; | |
188adeb2 | 478 | }; |
479 | struct Authmethod { | |
480 | char *name; /* string to compare against server's list */ | |
481 | int (*userauth)(Authctxt *authctxt); | |
482 | int *enabled; /* flag in option struct that enables method */ | |
483 | int *batch_flag; /* flag in option struct that disables method */ | |
484 | }; | |
485 | ||
486 | void input_userauth_success(int type, int plen, void *ctxt); | |
487 | void input_userauth_failure(int type, int plen, void *ctxt); | |
9616313f | 488 | void input_userauth_banner(int type, int plen, void *ctxt); |
188adeb2 | 489 | void input_userauth_error(int type, int plen, void *ctxt); |
94ec8c6b | 490 | void input_userauth_info_req(int type, int plen, void *ctxt); |
fee56204 | 491 | void input_userauth_pk_ok(int type, int plen, void *ctxt); |
94ec8c6b | 492 | |
493 | int userauth_none(Authctxt *authctxt); | |
188adeb2 | 494 | int userauth_pubkey(Authctxt *authctxt); |
495 | int userauth_passwd(Authctxt *authctxt); | |
94ec8c6b | 496 | int userauth_kbdint(Authctxt *authctxt); |
188adeb2 | 497 | |
fee56204 | 498 | void userauth(Authctxt *authctxt, char *authlist); |
499 | ||
500 | int | |
501 | sign_and_send_pubkey(Authctxt *authctxt, Key *k, | |
502 | sign_cb_fn *sign_callback); | |
503 | void clear_auth_state(Authctxt *authctxt); | |
504 | ||
94ec8c6b | 505 | Authmethod *authmethod_get(char *authlist); |
506 | Authmethod *authmethod_lookup(const char *name); | |
cab80f75 | 507 | char *authmethods_get(void); |
188adeb2 | 508 | |
509 | Authmethod authmethods[] = { | |
510 | {"publickey", | |
511 | userauth_pubkey, | |
fa08c86b | 512 | &options.pubkey_authentication, |
188adeb2 | 513 | NULL}, |
514 | {"password", | |
515 | userauth_passwd, | |
516 | &options.password_authentication, | |
517 | &options.batch_mode}, | |
94ec8c6b | 518 | {"keyboard-interactive", |
519 | userauth_kbdint, | |
520 | &options.kbd_interactive_authentication, | |
521 | &options.batch_mode}, | |
522 | {"none", | |
523 | userauth_none, | |
524 | NULL, | |
525 | NULL}, | |
188adeb2 | 526 | {NULL, NULL, NULL, NULL} |
527 | }; | |
528 | ||
529 | void | |
530 | ssh_userauth2(const char *server_user, char *host) | |
531 | { | |
532 | Authctxt authctxt; | |
533 | int type; | |
534 | int plen; | |
535 | ||
d464095c | 536 | if (options.challenge_reponse_authentication) |
537 | options.kbd_interactive_authentication = 1; | |
538 | ||
188adeb2 | 539 | debug("send SSH2_MSG_SERVICE_REQUEST"); |
540 | packet_start(SSH2_MSG_SERVICE_REQUEST); | |
541 | packet_put_cstring("ssh-userauth"); | |
542 | packet_send(); | |
543 | packet_write_wait(); | |
544 | type = packet_read(&plen); | |
545 | if (type != SSH2_MSG_SERVICE_ACCEPT) { | |
546 | fatal("denied SSH2_MSG_SERVICE_ACCEPT: %d", type); | |
547 | } | |
548 | if (packet_remaining() > 0) { | |
549 | char *reply = packet_get_string(&plen); | |
550 | debug("service_accept: %s", reply); | |
551 | xfree(reply); | |
188adeb2 | 552 | } else { |
553 | debug("buggy server: service_accept w/o service"); | |
554 | } | |
555 | packet_done(); | |
556 | debug("got SSH2_MSG_SERVICE_ACCEPT"); | |
557 | ||
cab80f75 | 558 | if (options.preferred_authentications == NULL) |
559 | options.preferred_authentications = authmethods_get(); | |
560 | ||
188adeb2 | 561 | /* setup authentication context */ |
562 | authctxt.agent = ssh_get_authentication_connection(); | |
563 | authctxt.server_user = server_user; | |
564 | authctxt.host = host; | |
565 | authctxt.service = "ssh-connection"; /* service name */ | |
566 | authctxt.success = 0; | |
94ec8c6b | 567 | authctxt.method = authmethod_lookup("none"); |
fee56204 | 568 | authctxt.authlist = NULL; |
94ec8c6b | 569 | if (authctxt.method == NULL) |
570 | fatal("ssh_userauth2: internal error: cannot send userauth none request"); | |
188adeb2 | 571 | |
572 | /* initial userauth request */ | |
94ec8c6b | 573 | userauth_none(&authctxt); |
188adeb2 | 574 | |
575 | dispatch_init(&input_userauth_error); | |
576 | dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); | |
577 | dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure); | |
9616313f | 578 | dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner); |
188adeb2 | 579 | dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */ |
580 | ||
581 | if (authctxt.agent != NULL) | |
582 | ssh_close_authentication_connection(authctxt.agent); | |
583 | ||
8abcdba4 | 584 | debug("ssh-userauth2 successful: method %s", authctxt.method->name); |
188adeb2 | 585 | } |
586 | void | |
fee56204 | 587 | userauth(Authctxt *authctxt, char *authlist) |
588 | { | |
589 | if (authlist == NULL) { | |
590 | authlist = authctxt->authlist; | |
591 | } else { | |
592 | if (authctxt->authlist) | |
593 | xfree(authctxt->authlist); | |
594 | authctxt->authlist = authlist; | |
595 | } | |
596 | for (;;) { | |
597 | Authmethod *method = authmethod_get(authlist); | |
598 | if (method == NULL) | |
599 | fatal("Permission denied (%s).", authlist); | |
600 | authctxt->method = method; | |
601 | if (method->userauth(authctxt) != 0) { | |
602 | debug2("we sent a %s packet, wait for reply", method->name); | |
603 | break; | |
604 | } else { | |
605 | debug2("we did not send a packet, disable method"); | |
606 | method->enabled = NULL; | |
607 | } | |
608 | } | |
609 | } | |
610 | void | |
188adeb2 | 611 | input_userauth_error(int type, int plen, void *ctxt) |
612 | { | |
9616313f | 613 | fatal("input_userauth_error: bad message during authentication: " |
614 | "type %d", type); | |
615 | } | |
616 | void | |
617 | input_userauth_banner(int type, int plen, void *ctxt) | |
618 | { | |
619 | char *msg, *lang; | |
620 | debug3("input_userauth_banner"); | |
621 | msg = packet_get_string(NULL); | |
622 | lang = packet_get_string(NULL); | |
623 | fprintf(stderr, "%s", msg); | |
624 | xfree(msg); | |
625 | xfree(lang); | |
188adeb2 | 626 | } |
627 | void | |
628 | input_userauth_success(int type, int plen, void *ctxt) | |
629 | { | |
630 | Authctxt *authctxt = ctxt; | |
631 | if (authctxt == NULL) | |
632 | fatal("input_userauth_success: no authentication context"); | |
fee56204 | 633 | if (authctxt->authlist) |
634 | xfree(authctxt->authlist); | |
635 | clear_auth_state(authctxt); | |
188adeb2 | 636 | authctxt->success = 1; /* break out */ |
637 | } | |
638 | void | |
639 | input_userauth_failure(int type, int plen, void *ctxt) | |
640 | { | |
188adeb2 | 641 | Authctxt *authctxt = ctxt; |
642 | char *authlist = NULL; | |
643 | int partial; | |
188adeb2 | 644 | |
645 | if (authctxt == NULL) | |
646 | fatal("input_userauth_failure: no authentication context"); | |
647 | ||
94ec8c6b | 648 | authlist = packet_get_string(NULL); |
188adeb2 | 649 | partial = packet_get_char(); |
650 | packet_done(); | |
651 | ||
652 | if (partial != 0) | |
f72e01a5 | 653 | log("Authenticated with partial success."); |
188adeb2 | 654 | debug("authentications that can continue: %s", authlist); |
655 | ||
fee56204 | 656 | clear_auth_state(authctxt); |
657 | userauth(authctxt, authlist); | |
658 | } | |
659 | void | |
660 | input_userauth_pk_ok(int type, int plen, void *ctxt) | |
661 | { | |
662 | Authctxt *authctxt = ctxt; | |
663 | Key *key = NULL; | |
664 | Buffer b; | |
665 | int alen, blen, pktype, sent = 0; | |
22138a36 | 666 | char *pkalg, *pkblob, *fp; |
fee56204 | 667 | |
668 | if (authctxt == NULL) | |
669 | fatal("input_userauth_pk_ok: no authentication context"); | |
670 | if (datafellows & SSH_BUG_PKOK) { | |
671 | /* this is similar to SSH_BUG_PKAUTH */ | |
672 | debug2("input_userauth_pk_ok: SSH_BUG_PKOK"); | |
673 | pkblob = packet_get_string(&blen); | |
674 | buffer_init(&b); | |
675 | buffer_append(&b, pkblob, blen); | |
676 | pkalg = buffer_get_string(&b, &alen); | |
677 | buffer_free(&b); | |
678 | } else { | |
679 | pkalg = packet_get_string(&alen); | |
680 | pkblob = packet_get_string(&blen); | |
681 | } | |
682 | packet_done(); | |
683 | ||
684 | debug("input_userauth_pk_ok: pkalg %s blen %d lastkey %p hint %d", | |
685 | pkalg, blen, authctxt->last_key, authctxt->last_key_hint); | |
686 | ||
687 | do { | |
688 | if (authctxt->last_key == NULL || | |
689 | authctxt->last_key_sign == NULL) { | |
690 | debug("no last key or no sign cb"); | |
188adeb2 | 691 | break; |
188adeb2 | 692 | } |
fee56204 | 693 | if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) { |
694 | debug("unknown pkalg %s", pkalg); | |
695 | break; | |
696 | } | |
697 | if ((key = key_from_blob(pkblob, blen)) == NULL) { | |
698 | debug("no key from blob. pkalg %s", pkalg); | |
699 | break; | |
700 | } | |
22138a36 | 701 | fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX); |
702 | debug2("input_userauth_pk_ok: fp %s", fp); | |
703 | xfree(fp); | |
fee56204 | 704 | if (!key_equal(key, authctxt->last_key)) { |
705 | debug("key != last_key"); | |
706 | break; | |
707 | } | |
708 | sent = sign_and_send_pubkey(authctxt, key, | |
709 | authctxt->last_key_sign); | |
710 | } while(0); | |
711 | ||
712 | if (key != NULL) | |
713 | key_free(key); | |
714 | xfree(pkalg); | |
715 | xfree(pkblob); | |
716 | ||
717 | /* unregister */ | |
718 | clear_auth_state(authctxt); | |
719 | dispatch_set(SSH2_MSG_USERAUTH_PK_OK, NULL); | |
720 | ||
721 | /* try another method if we did not send a packet*/ | |
722 | if (sent == 0) | |
723 | userauth(authctxt, NULL); | |
724 | ||
188adeb2 | 725 | } |
726 | ||
94ec8c6b | 727 | int |
728 | userauth_none(Authctxt *authctxt) | |
729 | { | |
730 | /* initial userauth request */ | |
731 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
732 | packet_put_cstring(authctxt->server_user); | |
733 | packet_put_cstring(authctxt->service); | |
734 | packet_put_cstring(authctxt->method->name); | |
735 | packet_send(); | |
94ec8c6b | 736 | return 1; |
737 | } | |
738 | ||
a306f2dd | 739 | int |
188adeb2 | 740 | userauth_passwd(Authctxt *authctxt) |
a306f2dd | 741 | { |
1d1ffb87 | 742 | static int attempt = 0; |
a306f2dd | 743 | char prompt[80]; |
744 | char *password; | |
745 | ||
fa649821 | 746 | if (attempt++ >= options.number_of_password_prompts) |
1d1ffb87 | 747 | return 0; |
748 | ||
fa649821 | 749 | if(attempt != 1) |
750 | error("Permission denied, please try again."); | |
751 | ||
f72e01a5 | 752 | snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ", |
188adeb2 | 753 | authctxt->server_user, authctxt->host); |
a306f2dd | 754 | password = read_passphrase(prompt, 0); |
755 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
188adeb2 | 756 | packet_put_cstring(authctxt->server_user); |
757 | packet_put_cstring(authctxt->service); | |
94ec8c6b | 758 | packet_put_cstring(authctxt->method->name); |
a306f2dd | 759 | packet_put_char(0); |
a6215e53 | 760 | packet_put_cstring(password); |
a306f2dd | 761 | memset(password, 0, strlen(password)); |
762 | xfree(password); | |
a6215e53 | 763 | packet_inject_ignore(64); |
a306f2dd | 764 | packet_send(); |
a306f2dd | 765 | return 1; |
766 | } | |
767 | ||
fee56204 | 768 | void |
769 | clear_auth_state(Authctxt *authctxt) | |
770 | { | |
771 | /* XXX clear authentication state */ | |
772 | if (authctxt->last_key != NULL && authctxt->last_key_hint == -1) { | |
773 | debug3("clear_auth_state: key_free %p", authctxt->last_key); | |
774 | key_free(authctxt->last_key); | |
775 | } | |
776 | authctxt->last_key = NULL; | |
777 | authctxt->last_key_hint = -2; | |
778 | authctxt->last_key_sign = NULL; | |
779 | } | |
780 | ||
2e73a022 | 781 | int |
188adeb2 | 782 | sign_and_send_pubkey(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback) |
a306f2dd | 783 | { |
784 | Buffer b; | |
1e3b8b07 | 785 | u_char *blob, *signature; |
a306f2dd | 786 | int bloblen, slen; |
74fc9186 | 787 | int skip = 0; |
2e73a022 | 788 | int ret = -1; |
94ec8c6b | 789 | int have_sig = 1; |
a306f2dd | 790 | |
cbc5abf9 | 791 | debug3("sign_and_send_pubkey"); |
fee56204 | 792 | |
fa08c86b | 793 | if (key_to_blob(k, &blob, &bloblen) == 0) { |
794 | /* we cannot handle this key */ | |
cbc5abf9 | 795 | debug3("sign_and_send_pubkey: cannot handle key"); |
fa08c86b | 796 | return 0; |
797 | } | |
a306f2dd | 798 | /* data to be signed */ |
799 | buffer_init(&b); | |
33de75a3 | 800 | if (datafellows & SSH_OLD_SESSIONID) { |
74fc9186 | 801 | buffer_append(&b, session_id2, session_id2_len); |
2b87da3b | 802 | skip = session_id2_len; |
33de75a3 | 803 | } else { |
804 | buffer_put_string(&b, session_id2, session_id2_len); | |
805 | skip = buffer_len(&b); | |
74fc9186 | 806 | } |
a306f2dd | 807 | buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); |
188adeb2 | 808 | buffer_put_cstring(&b, authctxt->server_user); |
d0c832f3 | 809 | buffer_put_cstring(&b, |
cbc5abf9 | 810 | datafellows & SSH_BUG_PKSERVICE ? |
d0c832f3 | 811 | "ssh-userauth" : |
188adeb2 | 812 | authctxt->service); |
cbc5abf9 | 813 | if (datafellows & SSH_BUG_PKAUTH) { |
814 | buffer_put_char(&b, have_sig); | |
815 | } else { | |
816 | buffer_put_cstring(&b, authctxt->method->name); | |
817 | buffer_put_char(&b, have_sig); | |
2b87da3b | 818 | buffer_put_cstring(&b, key_ssh_name(k)); |
cbc5abf9 | 819 | } |
a306f2dd | 820 | buffer_put_string(&b, blob, bloblen); |
a306f2dd | 821 | |
822 | /* generate signature */ | |
fee56204 | 823 | ret = (*sign_callback)(authctxt, k, &signature, &slen, |
824 | buffer_ptr(&b), buffer_len(&b)); | |
2e73a022 | 825 | if (ret == -1) { |
826 | xfree(blob); | |
827 | buffer_free(&b); | |
828 | return 0; | |
829 | } | |
fa08c86b | 830 | #ifdef DEBUG_PK |
a306f2dd | 831 | buffer_dump(&b); |
832 | #endif | |
cbc5abf9 | 833 | if (datafellows & SSH_BUG_PKSERVICE) { |
d0c832f3 | 834 | buffer_clear(&b); |
835 | buffer_append(&b, session_id2, session_id2_len); | |
fee56204 | 836 | skip = session_id2_len; |
d0c832f3 | 837 | buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); |
188adeb2 | 838 | buffer_put_cstring(&b, authctxt->server_user); |
839 | buffer_put_cstring(&b, authctxt->service); | |
94ec8c6b | 840 | buffer_put_cstring(&b, authctxt->method->name); |
841 | buffer_put_char(&b, have_sig); | |
cbc5abf9 | 842 | if (!(datafellows & SSH_BUG_PKAUTH)) |
2b87da3b | 843 | buffer_put_cstring(&b, key_ssh_name(k)); |
d0c832f3 | 844 | buffer_put_string(&b, blob, bloblen); |
845 | } | |
846 | xfree(blob); | |
fee56204 | 847 | |
a306f2dd | 848 | /* append signature */ |
849 | buffer_put_string(&b, signature, slen); | |
850 | xfree(signature); | |
851 | ||
852 | /* skip session id and packet type */ | |
74fc9186 | 853 | if (buffer_len(&b) < skip + 1) |
188adeb2 | 854 | fatal("userauth_pubkey: internal error"); |
74fc9186 | 855 | buffer_consume(&b, skip + 1); |
a306f2dd | 856 | |
857 | /* put remaining data from buffer into packet */ | |
858 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
859 | packet_put_raw(buffer_ptr(&b), buffer_len(&b)); | |
860 | buffer_free(&b); | |
a306f2dd | 861 | packet_send(); |
2e73a022 | 862 | |
863 | return 1; | |
4c8722d9 | 864 | } |
865 | ||
866 | int | |
fee56204 | 867 | send_pubkey_test(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback, |
868 | int hint) | |
4c8722d9 | 869 | { |
fee56204 | 870 | u_char *blob; |
871 | int bloblen, have_sig = 0; | |
4c8722d9 | 872 | |
fee56204 | 873 | debug3("send_pubkey_test"); |
874 | ||
875 | if (key_to_blob(k, &blob, &bloblen) == 0) { | |
876 | /* we cannot handle this key */ | |
877 | debug3("send_pubkey_test: cannot handle key"); | |
4c8722d9 | 878 | return 0; |
879 | } | |
fee56204 | 880 | /* register callback for USERAUTH_PK_OK message */ |
881 | authctxt->last_key_sign = sign_callback; | |
882 | authctxt->last_key_hint = hint; | |
883 | authctxt->last_key = k; | |
884 | dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok); | |
4c8722d9 | 885 | |
fee56204 | 886 | packet_start(SSH2_MSG_USERAUTH_REQUEST); |
887 | packet_put_cstring(authctxt->server_user); | |
888 | packet_put_cstring(authctxt->service); | |
889 | packet_put_cstring(authctxt->method->name); | |
890 | packet_put_char(have_sig); | |
891 | if (!(datafellows & SSH_BUG_PKAUTH)) | |
892 | packet_put_cstring(key_ssh_name(k)); | |
893 | packet_put_string(blob, bloblen); | |
894 | xfree(blob); | |
895 | packet_send(); | |
896 | return 1; | |
897 | } | |
898 | ||
899 | Key * | |
900 | load_identity_file(char *filename) | |
901 | { | |
902 | Key *private; | |
903 | char prompt[300], *passphrase; | |
aeaa3d9e | 904 | int quit, i; |
d156519a | 905 | struct stat st; |
fee56204 | 906 | |
d156519a | 907 | if (stat(filename, &st) < 0) { |
908 | debug3("no such identity: %s", filename); | |
909 | return NULL; | |
910 | } | |
aeaa3d9e | 911 | private = key_load_private_type(KEY_UNSPEC, filename, "", NULL); |
912 | if (private == NULL) { | |
913 | if (options.batch_mode) | |
fee56204 | 914 | return NULL; |
4c8722d9 | 915 | snprintf(prompt, sizeof prompt, |
fa08c86b | 916 | "Enter passphrase for key '%.100s': ", filename); |
188adeb2 | 917 | for (i = 0; i < options.number_of_password_prompts; i++) { |
918 | passphrase = read_passphrase(prompt, 0); | |
919 | if (strcmp(passphrase, "") != 0) { | |
aeaa3d9e | 920 | private = key_load_private_type(KEY_UNSPEC, filename, |
921 | passphrase, NULL); | |
fee56204 | 922 | quit = 0; |
188adeb2 | 923 | } else { |
924 | debug2("no passphrase given, try next key"); | |
fee56204 | 925 | quit = 1; |
188adeb2 | 926 | } |
927 | memset(passphrase, 0, strlen(passphrase)); | |
928 | xfree(passphrase); | |
aeaa3d9e | 929 | if (private != NULL || quit) |
188adeb2 | 930 | break; |
931 | debug2("bad passphrase given, try again..."); | |
932 | } | |
4c8722d9 | 933 | } |
fee56204 | 934 | return private; |
935 | } | |
936 | ||
937 | int | |
938 | identity_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp, | |
939 | u_char *data, int datalen) | |
940 | { | |
941 | Key *private; | |
942 | int idx, ret; | |
943 | ||
944 | idx = authctxt->last_key_hint; | |
945 | if (idx < 0) | |
946 | return -1; | |
947 | private = load_identity_file(options.identity_files[idx]); | |
948 | if (private == NULL) | |
949 | return -1; | |
950 | ret = key_sign(private, sigp, lenp, data, datalen); | |
951 | key_free(private); | |
2e73a022 | 952 | return ret; |
953 | } | |
954 | ||
1e3b8b07 | 955 | int agent_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp, |
956 | u_char *data, int datalen) | |
2e73a022 | 957 | { |
188adeb2 | 958 | return ssh_agent_sign(authctxt->agent, key, sigp, lenp, data, datalen); |
2e73a022 | 959 | } |
960 | ||
fee56204 | 961 | int key_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp, |
962 | u_char *data, int datalen) | |
963 | { | |
964 | return key_sign(key, sigp, lenp, data, datalen); | |
965 | } | |
966 | ||
2e73a022 | 967 | int |
188adeb2 | 968 | userauth_pubkey_agent(Authctxt *authctxt) |
2e73a022 | 969 | { |
970 | static int called = 0; | |
fa08c86b | 971 | int ret = 0; |
2e73a022 | 972 | char *comment; |
973 | Key *k; | |
2e73a022 | 974 | |
975 | if (called == 0) { | |
fa08c86b | 976 | if (ssh_get_num_identities(authctxt->agent, 2) == 0) |
977 | debug2("userauth_pubkey_agent: no keys at all"); | |
188adeb2 | 978 | called = 1; |
2e73a022 | 979 | } |
fa08c86b | 980 | k = ssh_get_next_identity(authctxt->agent, &comment, 2); |
188adeb2 | 981 | if (k == NULL) { |
fa08c86b | 982 | debug2("userauth_pubkey_agent: no more keys"); |
983 | } else { | |
fee56204 | 984 | debug("userauth_pubkey_agent: testing agent key %s", comment); |
fa08c86b | 985 | xfree(comment); |
fee56204 | 986 | ret = send_pubkey_test(authctxt, k, agent_sign_cb, -1); |
987 | if (ret == 0) | |
988 | key_free(k); | |
188adeb2 | 989 | } |
fa08c86b | 990 | if (ret == 0) |
991 | debug2("userauth_pubkey_agent: no message sent"); | |
2e73a022 | 992 | return ret; |
a306f2dd | 993 | } |
994 | ||
188adeb2 | 995 | int |
996 | userauth_pubkey(Authctxt *authctxt) | |
a306f2dd | 997 | { |
188adeb2 | 998 | static int idx = 0; |
999 | int sent = 0; | |
fee56204 | 1000 | Key *key; |
1001 | char *filename; | |
188adeb2 | 1002 | |
fa08c86b | 1003 | if (authctxt->agent != NULL) { |
1004 | do { | |
1005 | sent = userauth_pubkey_agent(authctxt); | |
1006 | } while(!sent && authctxt->agent->howmany > 0); | |
1007 | } | |
1008 | while (!sent && idx < options.num_identity_files) { | |
fee56204 | 1009 | key = options.identity_keys[idx]; |
1010 | filename = options.identity_files[idx]; | |
1011 | if (key == NULL) { | |
1012 | debug("try privkey: %s", filename); | |
1013 | key = load_identity_file(filename); | |
1014 | if (key != NULL) { | |
1015 | sent = sign_and_send_pubkey(authctxt, key, | |
1016 | key_sign_cb); | |
1017 | key_free(key); | |
1018 | } | |
1019 | } else if (key->type != KEY_RSA1) { | |
1020 | debug("try pubkey: %s", filename); | |
1021 | sent = send_pubkey_test(authctxt, key, | |
1022 | identity_sign_cb, idx); | |
1023 | } | |
fa08c86b | 1024 | idx++; |
1025 | } | |
188adeb2 | 1026 | return sent; |
1027 | } | |
a306f2dd | 1028 | |
94ec8c6b | 1029 | /* |
1030 | * Send userauth request message specifying keyboard-interactive method. | |
1031 | */ | |
1032 | int | |
1033 | userauth_kbdint(Authctxt *authctxt) | |
1034 | { | |
1035 | static int attempt = 0; | |
1036 | ||
1037 | if (attempt++ >= options.number_of_password_prompts) | |
1038 | return 0; | |
1039 | ||
1040 | debug2("userauth_kbdint"); | |
1041 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
1042 | packet_put_cstring(authctxt->server_user); | |
1043 | packet_put_cstring(authctxt->service); | |
1044 | packet_put_cstring(authctxt->method->name); | |
1045 | packet_put_cstring(""); /* lang */ | |
1046 | packet_put_cstring(options.kbd_interactive_devices ? | |
1047 | options.kbd_interactive_devices : ""); | |
1048 | packet_send(); | |
94ec8c6b | 1049 | |
1050 | dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req); | |
1051 | return 1; | |
1052 | } | |
1053 | ||
1054 | /* | |
f72e01a5 | 1055 | * parse INFO_REQUEST, prompt user and send INFO_RESPONSE |
94ec8c6b | 1056 | */ |
1057 | void | |
1058 | input_userauth_info_req(int type, int plen, void *ctxt) | |
1059 | { | |
1060 | Authctxt *authctxt = ctxt; | |
f72e01a5 | 1061 | char *name, *inst, *lang, *prompt, *response; |
1e3b8b07 | 1062 | u_int num_prompts, i; |
94ec8c6b | 1063 | int echo = 0; |
1064 | ||
1065 | debug2("input_userauth_info_req"); | |
1066 | ||
1067 | if (authctxt == NULL) | |
1068 | fatal("input_userauth_info_req: no authentication context"); | |
1069 | ||
1070 | name = packet_get_string(NULL); | |
1071 | inst = packet_get_string(NULL); | |
1072 | lang = packet_get_string(NULL); | |
94ec8c6b | 1073 | if (strlen(name) > 0) |
1074 | cli_mesg(name); | |
94ec8c6b | 1075 | if (strlen(inst) > 0) |
1076 | cli_mesg(inst); | |
f72e01a5 | 1077 | xfree(name); |
94ec8c6b | 1078 | xfree(inst); |
f72e01a5 | 1079 | xfree(lang); |
94ec8c6b | 1080 | |
1081 | num_prompts = packet_get_int(); | |
1082 | /* | |
1083 | * Begin to build info response packet based on prompts requested. | |
1084 | * We commit to providing the correct number of responses, so if | |
1085 | * further on we run into a problem that prevents this, we have to | |
1086 | * be sure and clean this up and send a correct error response. | |
1087 | */ | |
1088 | packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE); | |
1089 | packet_put_int(num_prompts); | |
1090 | ||
1091 | for (i = 0; i < num_prompts; i++) { | |
1092 | prompt = packet_get_string(NULL); | |
1093 | echo = packet_get_char(); | |
1094 | ||
1095 | response = cli_prompt(prompt, echo); | |
1096 | ||
a6215e53 | 1097 | packet_put_cstring(response); |
94ec8c6b | 1098 | memset(response, 0, strlen(response)); |
1099 | xfree(response); | |
1100 | xfree(prompt); | |
1101 | } | |
1102 | packet_done(); /* done with parsing incoming message. */ | |
1103 | ||
a6215e53 | 1104 | packet_inject_ignore(64); |
94ec8c6b | 1105 | packet_send(); |
94ec8c6b | 1106 | } |
a306f2dd | 1107 | |
188adeb2 | 1108 | /* find auth method */ |
1109 | ||
188adeb2 | 1110 | /* |
1111 | * given auth method name, if configurable options permit this method fill | |
1112 | * in auth_ident field and return true, otherwise return false. | |
1113 | */ | |
1114 | int | |
1115 | authmethod_is_enabled(Authmethod *method) | |
1116 | { | |
1117 | if (method == NULL) | |
1118 | return 0; | |
1119 | /* return false if options indicate this method is disabled */ | |
1120 | if (method->enabled == NULL || *method->enabled == 0) | |
1121 | return 0; | |
1122 | /* return false if batch mode is enabled but method needs interactive mode */ | |
1123 | if (method->batch_flag != NULL && *method->batch_flag != 0) | |
1124 | return 0; | |
1125 | return 1; | |
1126 | } | |
a306f2dd | 1127 | |
188adeb2 | 1128 | Authmethod * |
1129 | authmethod_lookup(const char *name) | |
1130 | { | |
1131 | Authmethod *method = NULL; | |
1132 | if (name != NULL) | |
1133 | for (method = authmethods; method->name != NULL; method++) | |
1134 | if (strcmp(name, method->name) == 0) | |
1135 | return method; | |
1136 | debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); | |
1137 | return NULL; | |
1138 | } | |
1139 | ||
cab80f75 | 1140 | /* XXX internal state */ |
1141 | static Authmethod *current = NULL; | |
1142 | static char *supported = NULL; | |
1143 | static char *preferred = NULL; | |
188adeb2 | 1144 | /* |
1145 | * Given the authentication method list sent by the server, return the | |
1146 | * next method we should try. If the server initially sends a nil list, | |
cab80f75 | 1147 | * use a built-in default list. |
2b87da3b | 1148 | */ |
188adeb2 | 1149 | Authmethod * |
1150 | authmethod_get(char *authlist) | |
1151 | { | |
cab80f75 | 1152 | |
1153 | char *name = NULL; | |
1154 | int next; | |
2b87da3b | 1155 | |
188adeb2 | 1156 | /* Use a suitable default if we're passed a nil list. */ |
1157 | if (authlist == NULL || strlen(authlist) == 0) | |
cab80f75 | 1158 | authlist = options.preferred_authentications; |
1159 | ||
1160 | if (supported == NULL || strcmp(authlist, supported) != 0) { | |
1161 | debug3("start over, passed a different list %s", authlist); | |
1162 | if (supported != NULL) | |
1163 | xfree(supported); | |
1164 | supported = xstrdup(authlist); | |
1165 | preferred = options.preferred_authentications; | |
1166 | debug3("preferred %s", preferred); | |
1167 | current = NULL; | |
1168 | } else if (current != NULL && authmethod_is_enabled(current)) | |
1169 | return current; | |
188adeb2 | 1170 | |
cab80f75 | 1171 | for (;;) { |
1172 | if ((name = match_list(preferred, supported, &next)) == NULL) { | |
1173 | debug("no more auth methods to try"); | |
1174 | current = NULL; | |
1175 | return NULL; | |
1176 | } | |
1177 | preferred += next; | |
94ec8c6b | 1178 | debug3("authmethod_lookup %s", name); |
cab80f75 | 1179 | debug3("remaining preferred: %s", preferred); |
1180 | if ((current = authmethod_lookup(name)) != NULL && | |
1181 | authmethod_is_enabled(current)) { | |
94ec8c6b | 1182 | debug3("authmethod_is_enabled %s", name); |
cab80f75 | 1183 | debug("next auth method to try is %s", name); |
1184 | return current; | |
94ec8c6b | 1185 | } |
a306f2dd | 1186 | } |
cab80f75 | 1187 | } |
a22aff1f | 1188 | |
a22aff1f | 1189 | |
cab80f75 | 1190 | #define DELIM "," |
1191 | char * | |
1192 | authmethods_get(void) | |
1193 | { | |
1194 | Authmethod *method = NULL; | |
1195 | char buf[1024]; | |
1196 | ||
1197 | buf[0] = '\0'; | |
1198 | for (method = authmethods; method->name != NULL; method++) { | |
1199 | if (authmethod_is_enabled(method)) { | |
1200 | if (buf[0] != '\0') | |
1201 | strlcat(buf, DELIM, sizeof buf); | |
1202 | strlcat(buf, method->name, sizeof buf); | |
1203 | } | |
1204 | } | |
1205 | return xstrdup(buf); | |
a306f2dd | 1206 | } |