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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" | |
e092ce67 | 26 | RCSID("$OpenBSD: sshconnect2.c,v 1.63 2001/04/04 00:06:54 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" |
db1cd2f3 | 49 | #include "dh.h" |
2e73a022 | 50 | #include "authfd.h" |
42f11eb2 | 51 | #include "log.h" |
52 | #include "readconf.h" | |
53 | #include "readpass.h" | |
cab80f75 | 54 | #include "match.h" |
a5c9ffdb | 55 | #include "dispatch.h" |
94ec8c6b | 56 | |
a306f2dd | 57 | /* import */ |
58 | extern char *client_version_string; | |
59 | extern char *server_version_string; | |
60 | extern Options options; | |
61 | ||
62 | /* | |
63 | * SSH2 key exchange | |
64 | */ | |
65 | ||
1e3b8b07 | 66 | u_char *session_id2 = NULL; |
a306f2dd | 67 | int session_id2_len = 0; |
68 | ||
a5c9ffdb | 69 | char *xxx_host; |
70 | struct sockaddr *xxx_hostaddr; | |
71 | ||
e092ce67 | 72 | Kex *xxx_kex = NULL; |
73 | ||
a5c9ffdb | 74 | int |
75 | check_host_key_callback(Key *hostkey) | |
76 | { | |
77 | check_host_key(xxx_host, xxx_hostaddr, hostkey, | |
78 | options.user_hostfile2, options.system_hostfile2); | |
79 | return 0; | |
80 | } | |
81 | ||
a306f2dd | 82 | void |
94ec8c6b | 83 | ssh_kex2(char *host, struct sockaddr *hostaddr) |
84 | { | |
94ec8c6b | 85 | Kex *kex; |
a5c9ffdb | 86 | |
87 | xxx_host = host; | |
88 | xxx_hostaddr = hostaddr; | |
94ec8c6b | 89 | |
c523303b | 90 | if (options.ciphers == (char *)-1) { |
91 | log("No valid ciphers for protocol version 2 given, using defaults."); | |
92 | options.ciphers = NULL; | |
94ec8c6b | 93 | } |
94 | if (options.ciphers != NULL) { | |
95 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = | |
96 | myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; | |
97 | } | |
1ad64a93 | 98 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = |
99 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); | |
100 | myproposal[PROPOSAL_ENC_ALGS_STOC] = | |
101 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); | |
94ec8c6b | 102 | if (options.compression) { |
b2552997 | 103 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = |
94ec8c6b | 104 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib"; |
105 | } else { | |
b2552997 | 106 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = |
94ec8c6b | 107 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none"; |
108 | } | |
b2552997 | 109 | if (options.macs != NULL) { |
110 | myproposal[PROPOSAL_MAC_ALGS_CTOS] = | |
111 | myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; | |
112 | } | |
94ec8c6b | 113 | |
a5c9ffdb | 114 | kex = kex_start(myproposal); |
115 | kex->client_version_string=client_version_string; | |
116 | kex->server_version_string=server_version_string; | |
117 | kex->check_host_key=&check_host_key_callback; | |
94ec8c6b | 118 | |
e092ce67 | 119 | xxx_kex = kex; |
120 | ||
a5c9ffdb | 121 | /* start key exchange */ |
122 | dispatch_run(DISPATCH_BLOCK, &kex->newkeys, kex); | |
94ec8c6b | 123 | |
d1ac6175 | 124 | session_id2 = kex->session_id; |
125 | session_id2_len = kex->session_id_len; | |
126 | ||
94ec8c6b | 127 | #ifdef DEBUG_KEXDH |
128 | /* send 1st encrypted/maced/compressed message */ | |
129 | packet_start(SSH2_MSG_IGNORE); | |
130 | packet_put_cstring("markus"); | |
131 | packet_send(); | |
132 | packet_write_wait(); | |
133 | #endif | |
a5c9ffdb | 134 | debug("done: ssh_kex2."); |
a306f2dd | 135 | } |
71276795 | 136 | |
a306f2dd | 137 | /* |
138 | * Authenticate user | |
139 | */ | |
188adeb2 | 140 | |
141 | typedef struct Authctxt Authctxt; | |
142 | typedef struct Authmethod Authmethod; | |
143 | ||
144 | typedef int sign_cb_fn( | |
145 | Authctxt *authctxt, Key *key, | |
1e3b8b07 | 146 | u_char **sigp, int *lenp, u_char *data, int datalen); |
188adeb2 | 147 | |
148 | struct Authctxt { | |
149 | const char *server_user; | |
150 | const char *host; | |
151 | const char *service; | |
152 | AuthenticationConnection *agent; | |
188adeb2 | 153 | Authmethod *method; |
94ec8c6b | 154 | int success; |
fee56204 | 155 | char *authlist; |
156 | Key *last_key; | |
157 | sign_cb_fn *last_key_sign; | |
158 | int last_key_hint; | |
188adeb2 | 159 | }; |
160 | struct Authmethod { | |
161 | char *name; /* string to compare against server's list */ | |
162 | int (*userauth)(Authctxt *authctxt); | |
163 | int *enabled; /* flag in option struct that enables method */ | |
164 | int *batch_flag; /* flag in option struct that disables method */ | |
165 | }; | |
166 | ||
167 | void input_userauth_success(int type, int plen, void *ctxt); | |
168 | void input_userauth_failure(int type, int plen, void *ctxt); | |
9616313f | 169 | void input_userauth_banner(int type, int plen, void *ctxt); |
188adeb2 | 170 | void input_userauth_error(int type, int plen, void *ctxt); |
94ec8c6b | 171 | void input_userauth_info_req(int type, int plen, void *ctxt); |
fee56204 | 172 | void input_userauth_pk_ok(int type, int plen, void *ctxt); |
94ec8c6b | 173 | |
174 | int userauth_none(Authctxt *authctxt); | |
188adeb2 | 175 | int userauth_pubkey(Authctxt *authctxt); |
176 | int userauth_passwd(Authctxt *authctxt); | |
94ec8c6b | 177 | int userauth_kbdint(Authctxt *authctxt); |
188adeb2 | 178 | |
fee56204 | 179 | void userauth(Authctxt *authctxt, char *authlist); |
180 | ||
181 | int | |
182 | sign_and_send_pubkey(Authctxt *authctxt, Key *k, | |
183 | sign_cb_fn *sign_callback); | |
184 | void clear_auth_state(Authctxt *authctxt); | |
185 | ||
94ec8c6b | 186 | Authmethod *authmethod_get(char *authlist); |
187 | Authmethod *authmethod_lookup(const char *name); | |
cab80f75 | 188 | char *authmethods_get(void); |
188adeb2 | 189 | |
190 | Authmethod authmethods[] = { | |
191 | {"publickey", | |
192 | userauth_pubkey, | |
fa08c86b | 193 | &options.pubkey_authentication, |
188adeb2 | 194 | NULL}, |
195 | {"password", | |
196 | userauth_passwd, | |
197 | &options.password_authentication, | |
198 | &options.batch_mode}, | |
94ec8c6b | 199 | {"keyboard-interactive", |
200 | userauth_kbdint, | |
201 | &options.kbd_interactive_authentication, | |
202 | &options.batch_mode}, | |
203 | {"none", | |
204 | userauth_none, | |
205 | NULL, | |
206 | NULL}, | |
188adeb2 | 207 | {NULL, NULL, NULL, NULL} |
208 | }; | |
209 | ||
210 | void | |
211 | ssh_userauth2(const char *server_user, char *host) | |
212 | { | |
213 | Authctxt authctxt; | |
214 | int type; | |
215 | int plen; | |
a5c9ffdb | 216 | int i; |
188adeb2 | 217 | |
d464095c | 218 | if (options.challenge_reponse_authentication) |
219 | options.kbd_interactive_authentication = 1; | |
220 | ||
188adeb2 | 221 | debug("send SSH2_MSG_SERVICE_REQUEST"); |
222 | packet_start(SSH2_MSG_SERVICE_REQUEST); | |
223 | packet_put_cstring("ssh-userauth"); | |
224 | packet_send(); | |
225 | packet_write_wait(); | |
226 | type = packet_read(&plen); | |
227 | if (type != SSH2_MSG_SERVICE_ACCEPT) { | |
228 | fatal("denied SSH2_MSG_SERVICE_ACCEPT: %d", type); | |
229 | } | |
230 | if (packet_remaining() > 0) { | |
231 | char *reply = packet_get_string(&plen); | |
232 | debug("service_accept: %s", reply); | |
233 | xfree(reply); | |
188adeb2 | 234 | } else { |
235 | debug("buggy server: service_accept w/o service"); | |
236 | } | |
237 | packet_done(); | |
238 | debug("got SSH2_MSG_SERVICE_ACCEPT"); | |
239 | ||
cab80f75 | 240 | if (options.preferred_authentications == NULL) |
241 | options.preferred_authentications = authmethods_get(); | |
242 | ||
188adeb2 | 243 | /* setup authentication context */ |
244 | authctxt.agent = ssh_get_authentication_connection(); | |
245 | authctxt.server_user = server_user; | |
246 | authctxt.host = host; | |
247 | authctxt.service = "ssh-connection"; /* service name */ | |
248 | authctxt.success = 0; | |
94ec8c6b | 249 | authctxt.method = authmethod_lookup("none"); |
fee56204 | 250 | authctxt.authlist = NULL; |
94ec8c6b | 251 | if (authctxt.method == NULL) |
252 | fatal("ssh_userauth2: internal error: cannot send userauth none request"); | |
188adeb2 | 253 | |
254 | /* initial userauth request */ | |
94ec8c6b | 255 | userauth_none(&authctxt); |
188adeb2 | 256 | |
a5c9ffdb | 257 | //dispatch_init(&input_userauth_error); |
258 | for (i = 50; i <= 254; i++) { | |
259 | dispatch_set(i, &input_userauth_error); | |
260 | } | |
188adeb2 | 261 | dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); |
262 | dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure); | |
9616313f | 263 | dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner); |
188adeb2 | 264 | dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */ |
265 | ||
266 | if (authctxt.agent != NULL) | |
267 | ssh_close_authentication_connection(authctxt.agent); | |
268 | ||
8abcdba4 | 269 | debug("ssh-userauth2 successful: method %s", authctxt.method->name); |
188adeb2 | 270 | } |
271 | void | |
fee56204 | 272 | userauth(Authctxt *authctxt, char *authlist) |
273 | { | |
274 | if (authlist == NULL) { | |
275 | authlist = authctxt->authlist; | |
276 | } else { | |
277 | if (authctxt->authlist) | |
278 | xfree(authctxt->authlist); | |
279 | authctxt->authlist = authlist; | |
280 | } | |
281 | for (;;) { | |
282 | Authmethod *method = authmethod_get(authlist); | |
283 | if (method == NULL) | |
284 | fatal("Permission denied (%s).", authlist); | |
285 | authctxt->method = method; | |
286 | if (method->userauth(authctxt) != 0) { | |
287 | debug2("we sent a %s packet, wait for reply", method->name); | |
288 | break; | |
289 | } else { | |
290 | debug2("we did not send a packet, disable method"); | |
291 | method->enabled = NULL; | |
292 | } | |
293 | } | |
294 | } | |
295 | void | |
188adeb2 | 296 | input_userauth_error(int type, int plen, void *ctxt) |
297 | { | |
9616313f | 298 | fatal("input_userauth_error: bad message during authentication: " |
299 | "type %d", type); | |
300 | } | |
301 | void | |
302 | input_userauth_banner(int type, int plen, void *ctxt) | |
303 | { | |
304 | char *msg, *lang; | |
305 | debug3("input_userauth_banner"); | |
306 | msg = packet_get_string(NULL); | |
307 | lang = packet_get_string(NULL); | |
308 | fprintf(stderr, "%s", msg); | |
309 | xfree(msg); | |
310 | xfree(lang); | |
188adeb2 | 311 | } |
312 | void | |
313 | input_userauth_success(int type, int plen, void *ctxt) | |
314 | { | |
315 | Authctxt *authctxt = ctxt; | |
316 | if (authctxt == NULL) | |
317 | fatal("input_userauth_success: no authentication context"); | |
fee56204 | 318 | if (authctxt->authlist) |
319 | xfree(authctxt->authlist); | |
320 | clear_auth_state(authctxt); | |
188adeb2 | 321 | authctxt->success = 1; /* break out */ |
322 | } | |
323 | void | |
324 | input_userauth_failure(int type, int plen, void *ctxt) | |
325 | { | |
188adeb2 | 326 | Authctxt *authctxt = ctxt; |
327 | char *authlist = NULL; | |
328 | int partial; | |
188adeb2 | 329 | |
330 | if (authctxt == NULL) | |
331 | fatal("input_userauth_failure: no authentication context"); | |
332 | ||
94ec8c6b | 333 | authlist = packet_get_string(NULL); |
188adeb2 | 334 | partial = packet_get_char(); |
335 | packet_done(); | |
336 | ||
337 | if (partial != 0) | |
f72e01a5 | 338 | log("Authenticated with partial success."); |
188adeb2 | 339 | debug("authentications that can continue: %s", authlist); |
340 | ||
fee56204 | 341 | clear_auth_state(authctxt); |
342 | userauth(authctxt, authlist); | |
343 | } | |
344 | void | |
345 | input_userauth_pk_ok(int type, int plen, void *ctxt) | |
346 | { | |
347 | Authctxt *authctxt = ctxt; | |
348 | Key *key = NULL; | |
349 | Buffer b; | |
350 | int alen, blen, pktype, sent = 0; | |
22138a36 | 351 | char *pkalg, *pkblob, *fp; |
fee56204 | 352 | |
353 | if (authctxt == NULL) | |
354 | fatal("input_userauth_pk_ok: no authentication context"); | |
355 | if (datafellows & SSH_BUG_PKOK) { | |
356 | /* this is similar to SSH_BUG_PKAUTH */ | |
357 | debug2("input_userauth_pk_ok: SSH_BUG_PKOK"); | |
358 | pkblob = packet_get_string(&blen); | |
359 | buffer_init(&b); | |
360 | buffer_append(&b, pkblob, blen); | |
361 | pkalg = buffer_get_string(&b, &alen); | |
362 | buffer_free(&b); | |
363 | } else { | |
364 | pkalg = packet_get_string(&alen); | |
365 | pkblob = packet_get_string(&blen); | |
366 | } | |
367 | packet_done(); | |
368 | ||
369 | debug("input_userauth_pk_ok: pkalg %s blen %d lastkey %p hint %d", | |
370 | pkalg, blen, authctxt->last_key, authctxt->last_key_hint); | |
371 | ||
372 | do { | |
373 | if (authctxt->last_key == NULL || | |
374 | authctxt->last_key_sign == NULL) { | |
375 | debug("no last key or no sign cb"); | |
188adeb2 | 376 | break; |
188adeb2 | 377 | } |
fee56204 | 378 | if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) { |
379 | debug("unknown pkalg %s", pkalg); | |
380 | break; | |
381 | } | |
382 | if ((key = key_from_blob(pkblob, blen)) == NULL) { | |
383 | debug("no key from blob. pkalg %s", pkalg); | |
384 | break; | |
385 | } | |
22138a36 | 386 | fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX); |
387 | debug2("input_userauth_pk_ok: fp %s", fp); | |
388 | xfree(fp); | |
fee56204 | 389 | if (!key_equal(key, authctxt->last_key)) { |
390 | debug("key != last_key"); | |
391 | break; | |
392 | } | |
393 | sent = sign_and_send_pubkey(authctxt, key, | |
394 | authctxt->last_key_sign); | |
395 | } while(0); | |
396 | ||
397 | if (key != NULL) | |
398 | key_free(key); | |
399 | xfree(pkalg); | |
400 | xfree(pkblob); | |
401 | ||
402 | /* unregister */ | |
403 | clear_auth_state(authctxt); | |
404 | dispatch_set(SSH2_MSG_USERAUTH_PK_OK, NULL); | |
405 | ||
406 | /* try another method if we did not send a packet*/ | |
407 | if (sent == 0) | |
408 | userauth(authctxt, NULL); | |
409 | ||
188adeb2 | 410 | } |
411 | ||
94ec8c6b | 412 | int |
413 | userauth_none(Authctxt *authctxt) | |
414 | { | |
415 | /* initial userauth request */ | |
416 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
417 | packet_put_cstring(authctxt->server_user); | |
418 | packet_put_cstring(authctxt->service); | |
419 | packet_put_cstring(authctxt->method->name); | |
420 | packet_send(); | |
94ec8c6b | 421 | return 1; |
422 | } | |
423 | ||
a306f2dd | 424 | int |
188adeb2 | 425 | userauth_passwd(Authctxt *authctxt) |
a306f2dd | 426 | { |
1d1ffb87 | 427 | static int attempt = 0; |
a306f2dd | 428 | char prompt[80]; |
429 | char *password; | |
430 | ||
fa649821 | 431 | if (attempt++ >= options.number_of_password_prompts) |
1d1ffb87 | 432 | return 0; |
433 | ||
fa649821 | 434 | if(attempt != 1) |
435 | error("Permission denied, please try again."); | |
436 | ||
f72e01a5 | 437 | snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ", |
188adeb2 | 438 | authctxt->server_user, authctxt->host); |
a306f2dd | 439 | password = read_passphrase(prompt, 0); |
440 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
188adeb2 | 441 | packet_put_cstring(authctxt->server_user); |
442 | packet_put_cstring(authctxt->service); | |
94ec8c6b | 443 | packet_put_cstring(authctxt->method->name); |
a306f2dd | 444 | packet_put_char(0); |
a6215e53 | 445 | packet_put_cstring(password); |
a306f2dd | 446 | memset(password, 0, strlen(password)); |
447 | xfree(password); | |
a6215e53 | 448 | packet_inject_ignore(64); |
a306f2dd | 449 | packet_send(); |
a306f2dd | 450 | return 1; |
451 | } | |
452 | ||
fee56204 | 453 | void |
454 | clear_auth_state(Authctxt *authctxt) | |
455 | { | |
456 | /* XXX clear authentication state */ | |
457 | if (authctxt->last_key != NULL && authctxt->last_key_hint == -1) { | |
458 | debug3("clear_auth_state: key_free %p", authctxt->last_key); | |
459 | key_free(authctxt->last_key); | |
460 | } | |
461 | authctxt->last_key = NULL; | |
462 | authctxt->last_key_hint = -2; | |
463 | authctxt->last_key_sign = NULL; | |
464 | } | |
465 | ||
2e73a022 | 466 | int |
188adeb2 | 467 | sign_and_send_pubkey(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback) |
a306f2dd | 468 | { |
469 | Buffer b; | |
1e3b8b07 | 470 | u_char *blob, *signature; |
a306f2dd | 471 | int bloblen, slen; |
74fc9186 | 472 | int skip = 0; |
2e73a022 | 473 | int ret = -1; |
94ec8c6b | 474 | int have_sig = 1; |
a306f2dd | 475 | |
cbc5abf9 | 476 | debug3("sign_and_send_pubkey"); |
fee56204 | 477 | |
fa08c86b | 478 | if (key_to_blob(k, &blob, &bloblen) == 0) { |
479 | /* we cannot handle this key */ | |
cbc5abf9 | 480 | debug3("sign_and_send_pubkey: cannot handle key"); |
fa08c86b | 481 | return 0; |
482 | } | |
a306f2dd | 483 | /* data to be signed */ |
484 | buffer_init(&b); | |
33de75a3 | 485 | if (datafellows & SSH_OLD_SESSIONID) { |
74fc9186 | 486 | buffer_append(&b, session_id2, session_id2_len); |
2b87da3b | 487 | skip = session_id2_len; |
33de75a3 | 488 | } else { |
489 | buffer_put_string(&b, session_id2, session_id2_len); | |
490 | skip = buffer_len(&b); | |
74fc9186 | 491 | } |
a306f2dd | 492 | buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); |
188adeb2 | 493 | buffer_put_cstring(&b, authctxt->server_user); |
d0c832f3 | 494 | buffer_put_cstring(&b, |
cbc5abf9 | 495 | datafellows & SSH_BUG_PKSERVICE ? |
d0c832f3 | 496 | "ssh-userauth" : |
188adeb2 | 497 | authctxt->service); |
cbc5abf9 | 498 | if (datafellows & SSH_BUG_PKAUTH) { |
499 | buffer_put_char(&b, have_sig); | |
500 | } else { | |
501 | buffer_put_cstring(&b, authctxt->method->name); | |
502 | buffer_put_char(&b, have_sig); | |
2b87da3b | 503 | buffer_put_cstring(&b, key_ssh_name(k)); |
cbc5abf9 | 504 | } |
a306f2dd | 505 | buffer_put_string(&b, blob, bloblen); |
a306f2dd | 506 | |
507 | /* generate signature */ | |
fee56204 | 508 | ret = (*sign_callback)(authctxt, k, &signature, &slen, |
509 | buffer_ptr(&b), buffer_len(&b)); | |
2e73a022 | 510 | if (ret == -1) { |
511 | xfree(blob); | |
512 | buffer_free(&b); | |
513 | return 0; | |
514 | } | |
fa08c86b | 515 | #ifdef DEBUG_PK |
a306f2dd | 516 | buffer_dump(&b); |
517 | #endif | |
cbc5abf9 | 518 | if (datafellows & SSH_BUG_PKSERVICE) { |
d0c832f3 | 519 | buffer_clear(&b); |
520 | buffer_append(&b, session_id2, session_id2_len); | |
fee56204 | 521 | skip = session_id2_len; |
d0c832f3 | 522 | buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); |
188adeb2 | 523 | buffer_put_cstring(&b, authctxt->server_user); |
524 | buffer_put_cstring(&b, authctxt->service); | |
94ec8c6b | 525 | buffer_put_cstring(&b, authctxt->method->name); |
526 | buffer_put_char(&b, have_sig); | |
cbc5abf9 | 527 | if (!(datafellows & SSH_BUG_PKAUTH)) |
2b87da3b | 528 | buffer_put_cstring(&b, key_ssh_name(k)); |
d0c832f3 | 529 | buffer_put_string(&b, blob, bloblen); |
530 | } | |
531 | xfree(blob); | |
fee56204 | 532 | |
a306f2dd | 533 | /* append signature */ |
534 | buffer_put_string(&b, signature, slen); | |
535 | xfree(signature); | |
536 | ||
537 | /* skip session id and packet type */ | |
74fc9186 | 538 | if (buffer_len(&b) < skip + 1) |
188adeb2 | 539 | fatal("userauth_pubkey: internal error"); |
74fc9186 | 540 | buffer_consume(&b, skip + 1); |
a306f2dd | 541 | |
542 | /* put remaining data from buffer into packet */ | |
543 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
544 | packet_put_raw(buffer_ptr(&b), buffer_len(&b)); | |
545 | buffer_free(&b); | |
a306f2dd | 546 | packet_send(); |
2e73a022 | 547 | |
548 | return 1; | |
4c8722d9 | 549 | } |
550 | ||
551 | int | |
fee56204 | 552 | send_pubkey_test(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback, |
553 | int hint) | |
4c8722d9 | 554 | { |
fee56204 | 555 | u_char *blob; |
556 | int bloblen, have_sig = 0; | |
4c8722d9 | 557 | |
fee56204 | 558 | debug3("send_pubkey_test"); |
559 | ||
560 | if (key_to_blob(k, &blob, &bloblen) == 0) { | |
561 | /* we cannot handle this key */ | |
562 | debug3("send_pubkey_test: cannot handle key"); | |
4c8722d9 | 563 | return 0; |
564 | } | |
fee56204 | 565 | /* register callback for USERAUTH_PK_OK message */ |
566 | authctxt->last_key_sign = sign_callback; | |
567 | authctxt->last_key_hint = hint; | |
568 | authctxt->last_key = k; | |
569 | dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok); | |
4c8722d9 | 570 | |
fee56204 | 571 | packet_start(SSH2_MSG_USERAUTH_REQUEST); |
572 | packet_put_cstring(authctxt->server_user); | |
573 | packet_put_cstring(authctxt->service); | |
574 | packet_put_cstring(authctxt->method->name); | |
575 | packet_put_char(have_sig); | |
576 | if (!(datafellows & SSH_BUG_PKAUTH)) | |
577 | packet_put_cstring(key_ssh_name(k)); | |
578 | packet_put_string(blob, bloblen); | |
579 | xfree(blob); | |
580 | packet_send(); | |
581 | return 1; | |
582 | } | |
583 | ||
584 | Key * | |
585 | load_identity_file(char *filename) | |
586 | { | |
587 | Key *private; | |
588 | char prompt[300], *passphrase; | |
aeaa3d9e | 589 | int quit, i; |
d156519a | 590 | struct stat st; |
fee56204 | 591 | |
d156519a | 592 | if (stat(filename, &st) < 0) { |
593 | debug3("no such identity: %s", filename); | |
594 | return NULL; | |
595 | } | |
aeaa3d9e | 596 | private = key_load_private_type(KEY_UNSPEC, filename, "", NULL); |
597 | if (private == NULL) { | |
598 | if (options.batch_mode) | |
fee56204 | 599 | return NULL; |
4c8722d9 | 600 | snprintf(prompt, sizeof prompt, |
fa08c86b | 601 | "Enter passphrase for key '%.100s': ", filename); |
188adeb2 | 602 | for (i = 0; i < options.number_of_password_prompts; i++) { |
603 | passphrase = read_passphrase(prompt, 0); | |
604 | if (strcmp(passphrase, "") != 0) { | |
aeaa3d9e | 605 | private = key_load_private_type(KEY_UNSPEC, filename, |
606 | passphrase, NULL); | |
fee56204 | 607 | quit = 0; |
188adeb2 | 608 | } else { |
609 | debug2("no passphrase given, try next key"); | |
fee56204 | 610 | quit = 1; |
188adeb2 | 611 | } |
612 | memset(passphrase, 0, strlen(passphrase)); | |
613 | xfree(passphrase); | |
aeaa3d9e | 614 | if (private != NULL || quit) |
188adeb2 | 615 | break; |
616 | debug2("bad passphrase given, try again..."); | |
617 | } | |
4c8722d9 | 618 | } |
fee56204 | 619 | return private; |
620 | } | |
621 | ||
622 | int | |
623 | identity_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp, | |
624 | u_char *data, int datalen) | |
625 | { | |
626 | Key *private; | |
627 | int idx, ret; | |
628 | ||
629 | idx = authctxt->last_key_hint; | |
630 | if (idx < 0) | |
631 | return -1; | |
632 | private = load_identity_file(options.identity_files[idx]); | |
633 | if (private == NULL) | |
634 | return -1; | |
635 | ret = key_sign(private, sigp, lenp, data, datalen); | |
636 | key_free(private); | |
2e73a022 | 637 | return ret; |
638 | } | |
639 | ||
1e3b8b07 | 640 | int agent_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp, |
641 | u_char *data, int datalen) | |
2e73a022 | 642 | { |
188adeb2 | 643 | return ssh_agent_sign(authctxt->agent, key, sigp, lenp, data, datalen); |
2e73a022 | 644 | } |
645 | ||
fee56204 | 646 | int key_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp, |
647 | u_char *data, int datalen) | |
648 | { | |
649 | return key_sign(key, sigp, lenp, data, datalen); | |
650 | } | |
651 | ||
2e73a022 | 652 | int |
188adeb2 | 653 | userauth_pubkey_agent(Authctxt *authctxt) |
2e73a022 | 654 | { |
655 | static int called = 0; | |
fa08c86b | 656 | int ret = 0; |
2e73a022 | 657 | char *comment; |
658 | Key *k; | |
2e73a022 | 659 | |
660 | if (called == 0) { | |
fa08c86b | 661 | if (ssh_get_num_identities(authctxt->agent, 2) == 0) |
662 | debug2("userauth_pubkey_agent: no keys at all"); | |
188adeb2 | 663 | called = 1; |
2e73a022 | 664 | } |
fa08c86b | 665 | k = ssh_get_next_identity(authctxt->agent, &comment, 2); |
188adeb2 | 666 | if (k == NULL) { |
fa08c86b | 667 | debug2("userauth_pubkey_agent: no more keys"); |
668 | } else { | |
fee56204 | 669 | debug("userauth_pubkey_agent: testing agent key %s", comment); |
fa08c86b | 670 | xfree(comment); |
fee56204 | 671 | ret = send_pubkey_test(authctxt, k, agent_sign_cb, -1); |
672 | if (ret == 0) | |
673 | key_free(k); | |
188adeb2 | 674 | } |
fa08c86b | 675 | if (ret == 0) |
676 | debug2("userauth_pubkey_agent: no message sent"); | |
2e73a022 | 677 | return ret; |
a306f2dd | 678 | } |
679 | ||
188adeb2 | 680 | int |
681 | userauth_pubkey(Authctxt *authctxt) | |
a306f2dd | 682 | { |
188adeb2 | 683 | static int idx = 0; |
684 | int sent = 0; | |
fee56204 | 685 | Key *key; |
686 | char *filename; | |
188adeb2 | 687 | |
fa08c86b | 688 | if (authctxt->agent != NULL) { |
689 | do { | |
690 | sent = userauth_pubkey_agent(authctxt); | |
691 | } while(!sent && authctxt->agent->howmany > 0); | |
692 | } | |
693 | while (!sent && idx < options.num_identity_files) { | |
fee56204 | 694 | key = options.identity_keys[idx]; |
695 | filename = options.identity_files[idx]; | |
696 | if (key == NULL) { | |
697 | debug("try privkey: %s", filename); | |
698 | key = load_identity_file(filename); | |
699 | if (key != NULL) { | |
700 | sent = sign_and_send_pubkey(authctxt, key, | |
701 | key_sign_cb); | |
702 | key_free(key); | |
703 | } | |
704 | } else if (key->type != KEY_RSA1) { | |
705 | debug("try pubkey: %s", filename); | |
706 | sent = send_pubkey_test(authctxt, key, | |
707 | identity_sign_cb, idx); | |
708 | } | |
fa08c86b | 709 | idx++; |
710 | } | |
188adeb2 | 711 | return sent; |
712 | } | |
a306f2dd | 713 | |
94ec8c6b | 714 | /* |
715 | * Send userauth request message specifying keyboard-interactive method. | |
716 | */ | |
717 | int | |
718 | userauth_kbdint(Authctxt *authctxt) | |
719 | { | |
720 | static int attempt = 0; | |
721 | ||
722 | if (attempt++ >= options.number_of_password_prompts) | |
723 | return 0; | |
724 | ||
725 | debug2("userauth_kbdint"); | |
726 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
727 | packet_put_cstring(authctxt->server_user); | |
728 | packet_put_cstring(authctxt->service); | |
729 | packet_put_cstring(authctxt->method->name); | |
730 | packet_put_cstring(""); /* lang */ | |
731 | packet_put_cstring(options.kbd_interactive_devices ? | |
732 | options.kbd_interactive_devices : ""); | |
733 | packet_send(); | |
94ec8c6b | 734 | |
735 | dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req); | |
736 | return 1; | |
737 | } | |
738 | ||
739 | /* | |
f72e01a5 | 740 | * parse INFO_REQUEST, prompt user and send INFO_RESPONSE |
94ec8c6b | 741 | */ |
742 | void | |
743 | input_userauth_info_req(int type, int plen, void *ctxt) | |
744 | { | |
745 | Authctxt *authctxt = ctxt; | |
f72e01a5 | 746 | char *name, *inst, *lang, *prompt, *response; |
1e3b8b07 | 747 | u_int num_prompts, i; |
94ec8c6b | 748 | int echo = 0; |
749 | ||
750 | debug2("input_userauth_info_req"); | |
751 | ||
752 | if (authctxt == NULL) | |
753 | fatal("input_userauth_info_req: no authentication context"); | |
754 | ||
755 | name = packet_get_string(NULL); | |
756 | inst = packet_get_string(NULL); | |
757 | lang = packet_get_string(NULL); | |
94ec8c6b | 758 | if (strlen(name) > 0) |
759 | cli_mesg(name); | |
94ec8c6b | 760 | if (strlen(inst) > 0) |
761 | cli_mesg(inst); | |
f72e01a5 | 762 | xfree(name); |
94ec8c6b | 763 | xfree(inst); |
f72e01a5 | 764 | xfree(lang); |
94ec8c6b | 765 | |
766 | num_prompts = packet_get_int(); | |
767 | /* | |
768 | * Begin to build info response packet based on prompts requested. | |
769 | * We commit to providing the correct number of responses, so if | |
770 | * further on we run into a problem that prevents this, we have to | |
771 | * be sure and clean this up and send a correct error response. | |
772 | */ | |
773 | packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE); | |
774 | packet_put_int(num_prompts); | |
775 | ||
776 | for (i = 0; i < num_prompts; i++) { | |
777 | prompt = packet_get_string(NULL); | |
778 | echo = packet_get_char(); | |
779 | ||
780 | response = cli_prompt(prompt, echo); | |
781 | ||
a6215e53 | 782 | packet_put_cstring(response); |
94ec8c6b | 783 | memset(response, 0, strlen(response)); |
784 | xfree(response); | |
785 | xfree(prompt); | |
786 | } | |
787 | packet_done(); /* done with parsing incoming message. */ | |
788 | ||
a6215e53 | 789 | packet_inject_ignore(64); |
94ec8c6b | 790 | packet_send(); |
94ec8c6b | 791 | } |
a306f2dd | 792 | |
188adeb2 | 793 | /* find auth method */ |
794 | ||
188adeb2 | 795 | /* |
796 | * given auth method name, if configurable options permit this method fill | |
797 | * in auth_ident field and return true, otherwise return false. | |
798 | */ | |
799 | int | |
800 | authmethod_is_enabled(Authmethod *method) | |
801 | { | |
802 | if (method == NULL) | |
803 | return 0; | |
804 | /* return false if options indicate this method is disabled */ | |
805 | if (method->enabled == NULL || *method->enabled == 0) | |
806 | return 0; | |
807 | /* return false if batch mode is enabled but method needs interactive mode */ | |
808 | if (method->batch_flag != NULL && *method->batch_flag != 0) | |
809 | return 0; | |
810 | return 1; | |
811 | } | |
a306f2dd | 812 | |
188adeb2 | 813 | Authmethod * |
814 | authmethod_lookup(const char *name) | |
815 | { | |
816 | Authmethod *method = NULL; | |
817 | if (name != NULL) | |
818 | for (method = authmethods; method->name != NULL; method++) | |
819 | if (strcmp(name, method->name) == 0) | |
820 | return method; | |
821 | debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); | |
822 | return NULL; | |
823 | } | |
824 | ||
cab80f75 | 825 | /* XXX internal state */ |
826 | static Authmethod *current = NULL; | |
827 | static char *supported = NULL; | |
828 | static char *preferred = NULL; | |
188adeb2 | 829 | /* |
830 | * Given the authentication method list sent by the server, return the | |
831 | * next method we should try. If the server initially sends a nil list, | |
cab80f75 | 832 | * use a built-in default list. |
2b87da3b | 833 | */ |
188adeb2 | 834 | Authmethod * |
835 | authmethod_get(char *authlist) | |
836 | { | |
cab80f75 | 837 | |
838 | char *name = NULL; | |
839 | int next; | |
2b87da3b | 840 | |
188adeb2 | 841 | /* Use a suitable default if we're passed a nil list. */ |
842 | if (authlist == NULL || strlen(authlist) == 0) | |
cab80f75 | 843 | authlist = options.preferred_authentications; |
844 | ||
845 | if (supported == NULL || strcmp(authlist, supported) != 0) { | |
846 | debug3("start over, passed a different list %s", authlist); | |
847 | if (supported != NULL) | |
848 | xfree(supported); | |
849 | supported = xstrdup(authlist); | |
850 | preferred = options.preferred_authentications; | |
851 | debug3("preferred %s", preferred); | |
852 | current = NULL; | |
853 | } else if (current != NULL && authmethod_is_enabled(current)) | |
854 | return current; | |
188adeb2 | 855 | |
cab80f75 | 856 | for (;;) { |
857 | if ((name = match_list(preferred, supported, &next)) == NULL) { | |
858 | debug("no more auth methods to try"); | |
859 | current = NULL; | |
860 | return NULL; | |
861 | } | |
862 | preferred += next; | |
94ec8c6b | 863 | debug3("authmethod_lookup %s", name); |
cab80f75 | 864 | debug3("remaining preferred: %s", preferred); |
865 | if ((current = authmethod_lookup(name)) != NULL && | |
866 | authmethod_is_enabled(current)) { | |
94ec8c6b | 867 | debug3("authmethod_is_enabled %s", name); |
cab80f75 | 868 | debug("next auth method to try is %s", name); |
869 | return current; | |
94ec8c6b | 870 | } |
a306f2dd | 871 | } |
cab80f75 | 872 | } |
a22aff1f | 873 | |
a22aff1f | 874 | |
cab80f75 | 875 | #define DELIM "," |
876 | char * | |
877 | authmethods_get(void) | |
878 | { | |
879 | Authmethod *method = NULL; | |
880 | char buf[1024]; | |
881 | ||
882 | buf[0] = '\0'; | |
883 | for (method = authmethods; method->name != NULL; method++) { | |
884 | if (authmethod_is_enabled(method)) { | |
885 | if (buf[0] != '\0') | |
886 | strlcat(buf, DELIM, sizeof buf); | |
887 | strlcat(buf, method->name, sizeof buf); | |
888 | } | |
889 | } | |
890 | return xstrdup(buf); | |
a306f2dd | 891 | } |