]>
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" | |
a5c9ffdb | 26 | RCSID("$OpenBSD: sshconnect2.c,v 1.61 2001/04/03 19:53:29 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 | ||
72 | int | |
73 | check_host_key_callback(Key *hostkey) | |
74 | { | |
75 | check_host_key(xxx_host, xxx_hostaddr, hostkey, | |
76 | options.user_hostfile2, options.system_hostfile2); | |
77 | return 0; | |
78 | } | |
79 | ||
a306f2dd | 80 | void |
94ec8c6b | 81 | ssh_kex2(char *host, struct sockaddr *hostaddr) |
82 | { | |
94ec8c6b | 83 | Kex *kex; |
a5c9ffdb | 84 | |
85 | xxx_host = host; | |
86 | xxx_hostaddr = hostaddr; | |
94ec8c6b | 87 | |
c523303b | 88 | if (options.ciphers == (char *)-1) { |
89 | log("No valid ciphers for protocol version 2 given, using defaults."); | |
90 | options.ciphers = NULL; | |
94ec8c6b | 91 | } |
92 | if (options.ciphers != NULL) { | |
93 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = | |
94 | myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; | |
95 | } | |
1ad64a93 | 96 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = |
97 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); | |
98 | myproposal[PROPOSAL_ENC_ALGS_STOC] = | |
99 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); | |
94ec8c6b | 100 | if (options.compression) { |
b2552997 | 101 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = |
94ec8c6b | 102 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib"; |
103 | } else { | |
b2552997 | 104 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = |
94ec8c6b | 105 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none"; |
106 | } | |
b2552997 | 107 | if (options.macs != NULL) { |
108 | myproposal[PROPOSAL_MAC_ALGS_CTOS] = | |
109 | myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; | |
110 | } | |
94ec8c6b | 111 | |
a5c9ffdb | 112 | kex = kex_start(myproposal); |
113 | kex->client_version_string=client_version_string; | |
114 | kex->server_version_string=server_version_string; | |
115 | kex->check_host_key=&check_host_key_callback; | |
94ec8c6b | 116 | |
a5c9ffdb | 117 | /* start key exchange */ |
118 | dispatch_run(DISPATCH_BLOCK, &kex->newkeys, kex); | |
94ec8c6b | 119 | |
120 | #ifdef DEBUG_KEXDH | |
121 | /* send 1st encrypted/maced/compressed message */ | |
122 | packet_start(SSH2_MSG_IGNORE); | |
123 | packet_put_cstring("markus"); | |
124 | packet_send(); | |
125 | packet_write_wait(); | |
126 | #endif | |
a5c9ffdb | 127 | debug("done: ssh_kex2."); |
a306f2dd | 128 | } |
71276795 | 129 | |
a306f2dd | 130 | /* |
131 | * Authenticate user | |
132 | */ | |
188adeb2 | 133 | |
134 | typedef struct Authctxt Authctxt; | |
135 | typedef struct Authmethod Authmethod; | |
136 | ||
137 | typedef int sign_cb_fn( | |
138 | Authctxt *authctxt, Key *key, | |
1e3b8b07 | 139 | u_char **sigp, int *lenp, u_char *data, int datalen); |
188adeb2 | 140 | |
141 | struct Authctxt { | |
142 | const char *server_user; | |
143 | const char *host; | |
144 | const char *service; | |
145 | AuthenticationConnection *agent; | |
188adeb2 | 146 | Authmethod *method; |
94ec8c6b | 147 | int success; |
fee56204 | 148 | char *authlist; |
149 | Key *last_key; | |
150 | sign_cb_fn *last_key_sign; | |
151 | int last_key_hint; | |
188adeb2 | 152 | }; |
153 | struct Authmethod { | |
154 | char *name; /* string to compare against server's list */ | |
155 | int (*userauth)(Authctxt *authctxt); | |
156 | int *enabled; /* flag in option struct that enables method */ | |
157 | int *batch_flag; /* flag in option struct that disables method */ | |
158 | }; | |
159 | ||
160 | void input_userauth_success(int type, int plen, void *ctxt); | |
161 | void input_userauth_failure(int type, int plen, void *ctxt); | |
9616313f | 162 | void input_userauth_banner(int type, int plen, void *ctxt); |
188adeb2 | 163 | void input_userauth_error(int type, int plen, void *ctxt); |
94ec8c6b | 164 | void input_userauth_info_req(int type, int plen, void *ctxt); |
fee56204 | 165 | void input_userauth_pk_ok(int type, int plen, void *ctxt); |
94ec8c6b | 166 | |
167 | int userauth_none(Authctxt *authctxt); | |
188adeb2 | 168 | int userauth_pubkey(Authctxt *authctxt); |
169 | int userauth_passwd(Authctxt *authctxt); | |
94ec8c6b | 170 | int userauth_kbdint(Authctxt *authctxt); |
188adeb2 | 171 | |
fee56204 | 172 | void userauth(Authctxt *authctxt, char *authlist); |
173 | ||
174 | int | |
175 | sign_and_send_pubkey(Authctxt *authctxt, Key *k, | |
176 | sign_cb_fn *sign_callback); | |
177 | void clear_auth_state(Authctxt *authctxt); | |
178 | ||
94ec8c6b | 179 | Authmethod *authmethod_get(char *authlist); |
180 | Authmethod *authmethod_lookup(const char *name); | |
cab80f75 | 181 | char *authmethods_get(void); |
188adeb2 | 182 | |
183 | Authmethod authmethods[] = { | |
184 | {"publickey", | |
185 | userauth_pubkey, | |
fa08c86b | 186 | &options.pubkey_authentication, |
188adeb2 | 187 | NULL}, |
188 | {"password", | |
189 | userauth_passwd, | |
190 | &options.password_authentication, | |
191 | &options.batch_mode}, | |
94ec8c6b | 192 | {"keyboard-interactive", |
193 | userauth_kbdint, | |
194 | &options.kbd_interactive_authentication, | |
195 | &options.batch_mode}, | |
196 | {"none", | |
197 | userauth_none, | |
198 | NULL, | |
199 | NULL}, | |
188adeb2 | 200 | {NULL, NULL, NULL, NULL} |
201 | }; | |
202 | ||
203 | void | |
204 | ssh_userauth2(const char *server_user, char *host) | |
205 | { | |
206 | Authctxt authctxt; | |
207 | int type; | |
208 | int plen; | |
a5c9ffdb | 209 | int i; |
188adeb2 | 210 | |
d464095c | 211 | if (options.challenge_reponse_authentication) |
212 | options.kbd_interactive_authentication = 1; | |
213 | ||
188adeb2 | 214 | debug("send SSH2_MSG_SERVICE_REQUEST"); |
215 | packet_start(SSH2_MSG_SERVICE_REQUEST); | |
216 | packet_put_cstring("ssh-userauth"); | |
217 | packet_send(); | |
218 | packet_write_wait(); | |
219 | type = packet_read(&plen); | |
220 | if (type != SSH2_MSG_SERVICE_ACCEPT) { | |
221 | fatal("denied SSH2_MSG_SERVICE_ACCEPT: %d", type); | |
222 | } | |
223 | if (packet_remaining() > 0) { | |
224 | char *reply = packet_get_string(&plen); | |
225 | debug("service_accept: %s", reply); | |
226 | xfree(reply); | |
188adeb2 | 227 | } else { |
228 | debug("buggy server: service_accept w/o service"); | |
229 | } | |
230 | packet_done(); | |
231 | debug("got SSH2_MSG_SERVICE_ACCEPT"); | |
232 | ||
cab80f75 | 233 | if (options.preferred_authentications == NULL) |
234 | options.preferred_authentications = authmethods_get(); | |
235 | ||
188adeb2 | 236 | /* setup authentication context */ |
237 | authctxt.agent = ssh_get_authentication_connection(); | |
238 | authctxt.server_user = server_user; | |
239 | authctxt.host = host; | |
240 | authctxt.service = "ssh-connection"; /* service name */ | |
241 | authctxt.success = 0; | |
94ec8c6b | 242 | authctxt.method = authmethod_lookup("none"); |
fee56204 | 243 | authctxt.authlist = NULL; |
94ec8c6b | 244 | if (authctxt.method == NULL) |
245 | fatal("ssh_userauth2: internal error: cannot send userauth none request"); | |
188adeb2 | 246 | |
247 | /* initial userauth request */ | |
94ec8c6b | 248 | userauth_none(&authctxt); |
188adeb2 | 249 | |
a5c9ffdb | 250 | //dispatch_init(&input_userauth_error); |
251 | for (i = 50; i <= 254; i++) { | |
252 | dispatch_set(i, &input_userauth_error); | |
253 | } | |
188adeb2 | 254 | dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); |
255 | dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure); | |
9616313f | 256 | dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner); |
188adeb2 | 257 | dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */ |
258 | ||
259 | if (authctxt.agent != NULL) | |
260 | ssh_close_authentication_connection(authctxt.agent); | |
261 | ||
8abcdba4 | 262 | debug("ssh-userauth2 successful: method %s", authctxt.method->name); |
188adeb2 | 263 | } |
264 | void | |
fee56204 | 265 | userauth(Authctxt *authctxt, char *authlist) |
266 | { | |
267 | if (authlist == NULL) { | |
268 | authlist = authctxt->authlist; | |
269 | } else { | |
270 | if (authctxt->authlist) | |
271 | xfree(authctxt->authlist); | |
272 | authctxt->authlist = authlist; | |
273 | } | |
274 | for (;;) { | |
275 | Authmethod *method = authmethod_get(authlist); | |
276 | if (method == NULL) | |
277 | fatal("Permission denied (%s).", authlist); | |
278 | authctxt->method = method; | |
279 | if (method->userauth(authctxt) != 0) { | |
280 | debug2("we sent a %s packet, wait for reply", method->name); | |
281 | break; | |
282 | } else { | |
283 | debug2("we did not send a packet, disable method"); | |
284 | method->enabled = NULL; | |
285 | } | |
286 | } | |
287 | } | |
288 | void | |
188adeb2 | 289 | input_userauth_error(int type, int plen, void *ctxt) |
290 | { | |
9616313f | 291 | fatal("input_userauth_error: bad message during authentication: " |
292 | "type %d", type); | |
293 | } | |
294 | void | |
295 | input_userauth_banner(int type, int plen, void *ctxt) | |
296 | { | |
297 | char *msg, *lang; | |
298 | debug3("input_userauth_banner"); | |
299 | msg = packet_get_string(NULL); | |
300 | lang = packet_get_string(NULL); | |
301 | fprintf(stderr, "%s", msg); | |
302 | xfree(msg); | |
303 | xfree(lang); | |
188adeb2 | 304 | } |
305 | void | |
306 | input_userauth_success(int type, int plen, void *ctxt) | |
307 | { | |
308 | Authctxt *authctxt = ctxt; | |
309 | if (authctxt == NULL) | |
310 | fatal("input_userauth_success: no authentication context"); | |
fee56204 | 311 | if (authctxt->authlist) |
312 | xfree(authctxt->authlist); | |
313 | clear_auth_state(authctxt); | |
188adeb2 | 314 | authctxt->success = 1; /* break out */ |
315 | } | |
316 | void | |
317 | input_userauth_failure(int type, int plen, void *ctxt) | |
318 | { | |
188adeb2 | 319 | Authctxt *authctxt = ctxt; |
320 | char *authlist = NULL; | |
321 | int partial; | |
188adeb2 | 322 | |
323 | if (authctxt == NULL) | |
324 | fatal("input_userauth_failure: no authentication context"); | |
325 | ||
94ec8c6b | 326 | authlist = packet_get_string(NULL); |
188adeb2 | 327 | partial = packet_get_char(); |
328 | packet_done(); | |
329 | ||
330 | if (partial != 0) | |
f72e01a5 | 331 | log("Authenticated with partial success."); |
188adeb2 | 332 | debug("authentications that can continue: %s", authlist); |
333 | ||
fee56204 | 334 | clear_auth_state(authctxt); |
335 | userauth(authctxt, authlist); | |
336 | } | |
337 | void | |
338 | input_userauth_pk_ok(int type, int plen, void *ctxt) | |
339 | { | |
340 | Authctxt *authctxt = ctxt; | |
341 | Key *key = NULL; | |
342 | Buffer b; | |
343 | int alen, blen, pktype, sent = 0; | |
22138a36 | 344 | char *pkalg, *pkblob, *fp; |
fee56204 | 345 | |
346 | if (authctxt == NULL) | |
347 | fatal("input_userauth_pk_ok: no authentication context"); | |
348 | if (datafellows & SSH_BUG_PKOK) { | |
349 | /* this is similar to SSH_BUG_PKAUTH */ | |
350 | debug2("input_userauth_pk_ok: SSH_BUG_PKOK"); | |
351 | pkblob = packet_get_string(&blen); | |
352 | buffer_init(&b); | |
353 | buffer_append(&b, pkblob, blen); | |
354 | pkalg = buffer_get_string(&b, &alen); | |
355 | buffer_free(&b); | |
356 | } else { | |
357 | pkalg = packet_get_string(&alen); | |
358 | pkblob = packet_get_string(&blen); | |
359 | } | |
360 | packet_done(); | |
361 | ||
362 | debug("input_userauth_pk_ok: pkalg %s blen %d lastkey %p hint %d", | |
363 | pkalg, blen, authctxt->last_key, authctxt->last_key_hint); | |
364 | ||
365 | do { | |
366 | if (authctxt->last_key == NULL || | |
367 | authctxt->last_key_sign == NULL) { | |
368 | debug("no last key or no sign cb"); | |
188adeb2 | 369 | break; |
188adeb2 | 370 | } |
fee56204 | 371 | if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) { |
372 | debug("unknown pkalg %s", pkalg); | |
373 | break; | |
374 | } | |
375 | if ((key = key_from_blob(pkblob, blen)) == NULL) { | |
376 | debug("no key from blob. pkalg %s", pkalg); | |
377 | break; | |
378 | } | |
22138a36 | 379 | fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX); |
380 | debug2("input_userauth_pk_ok: fp %s", fp); | |
381 | xfree(fp); | |
fee56204 | 382 | if (!key_equal(key, authctxt->last_key)) { |
383 | debug("key != last_key"); | |
384 | break; | |
385 | } | |
386 | sent = sign_and_send_pubkey(authctxt, key, | |
387 | authctxt->last_key_sign); | |
388 | } while(0); | |
389 | ||
390 | if (key != NULL) | |
391 | key_free(key); | |
392 | xfree(pkalg); | |
393 | xfree(pkblob); | |
394 | ||
395 | /* unregister */ | |
396 | clear_auth_state(authctxt); | |
397 | dispatch_set(SSH2_MSG_USERAUTH_PK_OK, NULL); | |
398 | ||
399 | /* try another method if we did not send a packet*/ | |
400 | if (sent == 0) | |
401 | userauth(authctxt, NULL); | |
402 | ||
188adeb2 | 403 | } |
404 | ||
94ec8c6b | 405 | int |
406 | userauth_none(Authctxt *authctxt) | |
407 | { | |
408 | /* initial userauth request */ | |
409 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
410 | packet_put_cstring(authctxt->server_user); | |
411 | packet_put_cstring(authctxt->service); | |
412 | packet_put_cstring(authctxt->method->name); | |
413 | packet_send(); | |
94ec8c6b | 414 | return 1; |
415 | } | |
416 | ||
a306f2dd | 417 | int |
188adeb2 | 418 | userauth_passwd(Authctxt *authctxt) |
a306f2dd | 419 | { |
1d1ffb87 | 420 | static int attempt = 0; |
a306f2dd | 421 | char prompt[80]; |
422 | char *password; | |
423 | ||
fa649821 | 424 | if (attempt++ >= options.number_of_password_prompts) |
1d1ffb87 | 425 | return 0; |
426 | ||
fa649821 | 427 | if(attempt != 1) |
428 | error("Permission denied, please try again."); | |
429 | ||
f72e01a5 | 430 | snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ", |
188adeb2 | 431 | authctxt->server_user, authctxt->host); |
a306f2dd | 432 | password = read_passphrase(prompt, 0); |
433 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
188adeb2 | 434 | packet_put_cstring(authctxt->server_user); |
435 | packet_put_cstring(authctxt->service); | |
94ec8c6b | 436 | packet_put_cstring(authctxt->method->name); |
a306f2dd | 437 | packet_put_char(0); |
a6215e53 | 438 | packet_put_cstring(password); |
a306f2dd | 439 | memset(password, 0, strlen(password)); |
440 | xfree(password); | |
a6215e53 | 441 | packet_inject_ignore(64); |
a306f2dd | 442 | packet_send(); |
a306f2dd | 443 | return 1; |
444 | } | |
445 | ||
fee56204 | 446 | void |
447 | clear_auth_state(Authctxt *authctxt) | |
448 | { | |
449 | /* XXX clear authentication state */ | |
450 | if (authctxt->last_key != NULL && authctxt->last_key_hint == -1) { | |
451 | debug3("clear_auth_state: key_free %p", authctxt->last_key); | |
452 | key_free(authctxt->last_key); | |
453 | } | |
454 | authctxt->last_key = NULL; | |
455 | authctxt->last_key_hint = -2; | |
456 | authctxt->last_key_sign = NULL; | |
457 | } | |
458 | ||
2e73a022 | 459 | int |
188adeb2 | 460 | sign_and_send_pubkey(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback) |
a306f2dd | 461 | { |
462 | Buffer b; | |
1e3b8b07 | 463 | u_char *blob, *signature; |
a306f2dd | 464 | int bloblen, slen; |
74fc9186 | 465 | int skip = 0; |
2e73a022 | 466 | int ret = -1; |
94ec8c6b | 467 | int have_sig = 1; |
a306f2dd | 468 | |
cbc5abf9 | 469 | debug3("sign_and_send_pubkey"); |
fee56204 | 470 | |
fa08c86b | 471 | if (key_to_blob(k, &blob, &bloblen) == 0) { |
472 | /* we cannot handle this key */ | |
cbc5abf9 | 473 | debug3("sign_and_send_pubkey: cannot handle key"); |
fa08c86b | 474 | return 0; |
475 | } | |
a306f2dd | 476 | /* data to be signed */ |
477 | buffer_init(&b); | |
33de75a3 | 478 | if (datafellows & SSH_OLD_SESSIONID) { |
74fc9186 | 479 | buffer_append(&b, session_id2, session_id2_len); |
2b87da3b | 480 | skip = session_id2_len; |
33de75a3 | 481 | } else { |
482 | buffer_put_string(&b, session_id2, session_id2_len); | |
483 | skip = buffer_len(&b); | |
74fc9186 | 484 | } |
a306f2dd | 485 | buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); |
188adeb2 | 486 | buffer_put_cstring(&b, authctxt->server_user); |
d0c832f3 | 487 | buffer_put_cstring(&b, |
cbc5abf9 | 488 | datafellows & SSH_BUG_PKSERVICE ? |
d0c832f3 | 489 | "ssh-userauth" : |
188adeb2 | 490 | authctxt->service); |
cbc5abf9 | 491 | if (datafellows & SSH_BUG_PKAUTH) { |
492 | buffer_put_char(&b, have_sig); | |
493 | } else { | |
494 | buffer_put_cstring(&b, authctxt->method->name); | |
495 | buffer_put_char(&b, have_sig); | |
2b87da3b | 496 | buffer_put_cstring(&b, key_ssh_name(k)); |
cbc5abf9 | 497 | } |
a306f2dd | 498 | buffer_put_string(&b, blob, bloblen); |
a306f2dd | 499 | |
500 | /* generate signature */ | |
fee56204 | 501 | ret = (*sign_callback)(authctxt, k, &signature, &slen, |
502 | buffer_ptr(&b), buffer_len(&b)); | |
2e73a022 | 503 | if (ret == -1) { |
504 | xfree(blob); | |
505 | buffer_free(&b); | |
506 | return 0; | |
507 | } | |
fa08c86b | 508 | #ifdef DEBUG_PK |
a306f2dd | 509 | buffer_dump(&b); |
510 | #endif | |
cbc5abf9 | 511 | if (datafellows & SSH_BUG_PKSERVICE) { |
d0c832f3 | 512 | buffer_clear(&b); |
513 | buffer_append(&b, session_id2, session_id2_len); | |
fee56204 | 514 | skip = session_id2_len; |
d0c832f3 | 515 | buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); |
188adeb2 | 516 | buffer_put_cstring(&b, authctxt->server_user); |
517 | buffer_put_cstring(&b, authctxt->service); | |
94ec8c6b | 518 | buffer_put_cstring(&b, authctxt->method->name); |
519 | buffer_put_char(&b, have_sig); | |
cbc5abf9 | 520 | if (!(datafellows & SSH_BUG_PKAUTH)) |
2b87da3b | 521 | buffer_put_cstring(&b, key_ssh_name(k)); |
d0c832f3 | 522 | buffer_put_string(&b, blob, bloblen); |
523 | } | |
524 | xfree(blob); | |
fee56204 | 525 | |
a306f2dd | 526 | /* append signature */ |
527 | buffer_put_string(&b, signature, slen); | |
528 | xfree(signature); | |
529 | ||
530 | /* skip session id and packet type */ | |
74fc9186 | 531 | if (buffer_len(&b) < skip + 1) |
188adeb2 | 532 | fatal("userauth_pubkey: internal error"); |
74fc9186 | 533 | buffer_consume(&b, skip + 1); |
a306f2dd | 534 | |
535 | /* put remaining data from buffer into packet */ | |
536 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
537 | packet_put_raw(buffer_ptr(&b), buffer_len(&b)); | |
538 | buffer_free(&b); | |
a306f2dd | 539 | packet_send(); |
2e73a022 | 540 | |
541 | return 1; | |
4c8722d9 | 542 | } |
543 | ||
544 | int | |
fee56204 | 545 | send_pubkey_test(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback, |
546 | int hint) | |
4c8722d9 | 547 | { |
fee56204 | 548 | u_char *blob; |
549 | int bloblen, have_sig = 0; | |
4c8722d9 | 550 | |
fee56204 | 551 | debug3("send_pubkey_test"); |
552 | ||
553 | if (key_to_blob(k, &blob, &bloblen) == 0) { | |
554 | /* we cannot handle this key */ | |
555 | debug3("send_pubkey_test: cannot handle key"); | |
4c8722d9 | 556 | return 0; |
557 | } | |
fee56204 | 558 | /* register callback for USERAUTH_PK_OK message */ |
559 | authctxt->last_key_sign = sign_callback; | |
560 | authctxt->last_key_hint = hint; | |
561 | authctxt->last_key = k; | |
562 | dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok); | |
4c8722d9 | 563 | |
fee56204 | 564 | packet_start(SSH2_MSG_USERAUTH_REQUEST); |
565 | packet_put_cstring(authctxt->server_user); | |
566 | packet_put_cstring(authctxt->service); | |
567 | packet_put_cstring(authctxt->method->name); | |
568 | packet_put_char(have_sig); | |
569 | if (!(datafellows & SSH_BUG_PKAUTH)) | |
570 | packet_put_cstring(key_ssh_name(k)); | |
571 | packet_put_string(blob, bloblen); | |
572 | xfree(blob); | |
573 | packet_send(); | |
574 | return 1; | |
575 | } | |
576 | ||
577 | Key * | |
578 | load_identity_file(char *filename) | |
579 | { | |
580 | Key *private; | |
581 | char prompt[300], *passphrase; | |
aeaa3d9e | 582 | int quit, i; |
d156519a | 583 | struct stat st; |
fee56204 | 584 | |
d156519a | 585 | if (stat(filename, &st) < 0) { |
586 | debug3("no such identity: %s", filename); | |
587 | return NULL; | |
588 | } | |
aeaa3d9e | 589 | private = key_load_private_type(KEY_UNSPEC, filename, "", NULL); |
590 | if (private == NULL) { | |
591 | if (options.batch_mode) | |
fee56204 | 592 | return NULL; |
4c8722d9 | 593 | snprintf(prompt, sizeof prompt, |
fa08c86b | 594 | "Enter passphrase for key '%.100s': ", filename); |
188adeb2 | 595 | for (i = 0; i < options.number_of_password_prompts; i++) { |
596 | passphrase = read_passphrase(prompt, 0); | |
597 | if (strcmp(passphrase, "") != 0) { | |
aeaa3d9e | 598 | private = key_load_private_type(KEY_UNSPEC, filename, |
599 | passphrase, NULL); | |
fee56204 | 600 | quit = 0; |
188adeb2 | 601 | } else { |
602 | debug2("no passphrase given, try next key"); | |
fee56204 | 603 | quit = 1; |
188adeb2 | 604 | } |
605 | memset(passphrase, 0, strlen(passphrase)); | |
606 | xfree(passphrase); | |
aeaa3d9e | 607 | if (private != NULL || quit) |
188adeb2 | 608 | break; |
609 | debug2("bad passphrase given, try again..."); | |
610 | } | |
4c8722d9 | 611 | } |
fee56204 | 612 | return private; |
613 | } | |
614 | ||
615 | int | |
616 | identity_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp, | |
617 | u_char *data, int datalen) | |
618 | { | |
619 | Key *private; | |
620 | int idx, ret; | |
621 | ||
622 | idx = authctxt->last_key_hint; | |
623 | if (idx < 0) | |
624 | return -1; | |
625 | private = load_identity_file(options.identity_files[idx]); | |
626 | if (private == NULL) | |
627 | return -1; | |
628 | ret = key_sign(private, sigp, lenp, data, datalen); | |
629 | key_free(private); | |
2e73a022 | 630 | return ret; |
631 | } | |
632 | ||
1e3b8b07 | 633 | int agent_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp, |
634 | u_char *data, int datalen) | |
2e73a022 | 635 | { |
188adeb2 | 636 | return ssh_agent_sign(authctxt->agent, key, sigp, lenp, data, datalen); |
2e73a022 | 637 | } |
638 | ||
fee56204 | 639 | int key_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp, |
640 | u_char *data, int datalen) | |
641 | { | |
642 | return key_sign(key, sigp, lenp, data, datalen); | |
643 | } | |
644 | ||
2e73a022 | 645 | int |
188adeb2 | 646 | userauth_pubkey_agent(Authctxt *authctxt) |
2e73a022 | 647 | { |
648 | static int called = 0; | |
fa08c86b | 649 | int ret = 0; |
2e73a022 | 650 | char *comment; |
651 | Key *k; | |
2e73a022 | 652 | |
653 | if (called == 0) { | |
fa08c86b | 654 | if (ssh_get_num_identities(authctxt->agent, 2) == 0) |
655 | debug2("userauth_pubkey_agent: no keys at all"); | |
188adeb2 | 656 | called = 1; |
2e73a022 | 657 | } |
fa08c86b | 658 | k = ssh_get_next_identity(authctxt->agent, &comment, 2); |
188adeb2 | 659 | if (k == NULL) { |
fa08c86b | 660 | debug2("userauth_pubkey_agent: no more keys"); |
661 | } else { | |
fee56204 | 662 | debug("userauth_pubkey_agent: testing agent key %s", comment); |
fa08c86b | 663 | xfree(comment); |
fee56204 | 664 | ret = send_pubkey_test(authctxt, k, agent_sign_cb, -1); |
665 | if (ret == 0) | |
666 | key_free(k); | |
188adeb2 | 667 | } |
fa08c86b | 668 | if (ret == 0) |
669 | debug2("userauth_pubkey_agent: no message sent"); | |
2e73a022 | 670 | return ret; |
a306f2dd | 671 | } |
672 | ||
188adeb2 | 673 | int |
674 | userauth_pubkey(Authctxt *authctxt) | |
a306f2dd | 675 | { |
188adeb2 | 676 | static int idx = 0; |
677 | int sent = 0; | |
fee56204 | 678 | Key *key; |
679 | char *filename; | |
188adeb2 | 680 | |
fa08c86b | 681 | if (authctxt->agent != NULL) { |
682 | do { | |
683 | sent = userauth_pubkey_agent(authctxt); | |
684 | } while(!sent && authctxt->agent->howmany > 0); | |
685 | } | |
686 | while (!sent && idx < options.num_identity_files) { | |
fee56204 | 687 | key = options.identity_keys[idx]; |
688 | filename = options.identity_files[idx]; | |
689 | if (key == NULL) { | |
690 | debug("try privkey: %s", filename); | |
691 | key = load_identity_file(filename); | |
692 | if (key != NULL) { | |
693 | sent = sign_and_send_pubkey(authctxt, key, | |
694 | key_sign_cb); | |
695 | key_free(key); | |
696 | } | |
697 | } else if (key->type != KEY_RSA1) { | |
698 | debug("try pubkey: %s", filename); | |
699 | sent = send_pubkey_test(authctxt, key, | |
700 | identity_sign_cb, idx); | |
701 | } | |
fa08c86b | 702 | idx++; |
703 | } | |
188adeb2 | 704 | return sent; |
705 | } | |
a306f2dd | 706 | |
94ec8c6b | 707 | /* |
708 | * Send userauth request message specifying keyboard-interactive method. | |
709 | */ | |
710 | int | |
711 | userauth_kbdint(Authctxt *authctxt) | |
712 | { | |
713 | static int attempt = 0; | |
714 | ||
715 | if (attempt++ >= options.number_of_password_prompts) | |
716 | return 0; | |
717 | ||
718 | debug2("userauth_kbdint"); | |
719 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
720 | packet_put_cstring(authctxt->server_user); | |
721 | packet_put_cstring(authctxt->service); | |
722 | packet_put_cstring(authctxt->method->name); | |
723 | packet_put_cstring(""); /* lang */ | |
724 | packet_put_cstring(options.kbd_interactive_devices ? | |
725 | options.kbd_interactive_devices : ""); | |
726 | packet_send(); | |
94ec8c6b | 727 | |
728 | dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req); | |
729 | return 1; | |
730 | } | |
731 | ||
732 | /* | |
f72e01a5 | 733 | * parse INFO_REQUEST, prompt user and send INFO_RESPONSE |
94ec8c6b | 734 | */ |
735 | void | |
736 | input_userauth_info_req(int type, int plen, void *ctxt) | |
737 | { | |
738 | Authctxt *authctxt = ctxt; | |
f72e01a5 | 739 | char *name, *inst, *lang, *prompt, *response; |
1e3b8b07 | 740 | u_int num_prompts, i; |
94ec8c6b | 741 | int echo = 0; |
742 | ||
743 | debug2("input_userauth_info_req"); | |
744 | ||
745 | if (authctxt == NULL) | |
746 | fatal("input_userauth_info_req: no authentication context"); | |
747 | ||
748 | name = packet_get_string(NULL); | |
749 | inst = packet_get_string(NULL); | |
750 | lang = packet_get_string(NULL); | |
94ec8c6b | 751 | if (strlen(name) > 0) |
752 | cli_mesg(name); | |
94ec8c6b | 753 | if (strlen(inst) > 0) |
754 | cli_mesg(inst); | |
f72e01a5 | 755 | xfree(name); |
94ec8c6b | 756 | xfree(inst); |
f72e01a5 | 757 | xfree(lang); |
94ec8c6b | 758 | |
759 | num_prompts = packet_get_int(); | |
760 | /* | |
761 | * Begin to build info response packet based on prompts requested. | |
762 | * We commit to providing the correct number of responses, so if | |
763 | * further on we run into a problem that prevents this, we have to | |
764 | * be sure and clean this up and send a correct error response. | |
765 | */ | |
766 | packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE); | |
767 | packet_put_int(num_prompts); | |
768 | ||
769 | for (i = 0; i < num_prompts; i++) { | |
770 | prompt = packet_get_string(NULL); | |
771 | echo = packet_get_char(); | |
772 | ||
773 | response = cli_prompt(prompt, echo); | |
774 | ||
a6215e53 | 775 | packet_put_cstring(response); |
94ec8c6b | 776 | memset(response, 0, strlen(response)); |
777 | xfree(response); | |
778 | xfree(prompt); | |
779 | } | |
780 | packet_done(); /* done with parsing incoming message. */ | |
781 | ||
a6215e53 | 782 | packet_inject_ignore(64); |
94ec8c6b | 783 | packet_send(); |
94ec8c6b | 784 | } |
a306f2dd | 785 | |
188adeb2 | 786 | /* find auth method */ |
787 | ||
188adeb2 | 788 | /* |
789 | * given auth method name, if configurable options permit this method fill | |
790 | * in auth_ident field and return true, otherwise return false. | |
791 | */ | |
792 | int | |
793 | authmethod_is_enabled(Authmethod *method) | |
794 | { | |
795 | if (method == NULL) | |
796 | return 0; | |
797 | /* return false if options indicate this method is disabled */ | |
798 | if (method->enabled == NULL || *method->enabled == 0) | |
799 | return 0; | |
800 | /* return false if batch mode is enabled but method needs interactive mode */ | |
801 | if (method->batch_flag != NULL && *method->batch_flag != 0) | |
802 | return 0; | |
803 | return 1; | |
804 | } | |
a306f2dd | 805 | |
188adeb2 | 806 | Authmethod * |
807 | authmethod_lookup(const char *name) | |
808 | { | |
809 | Authmethod *method = NULL; | |
810 | if (name != NULL) | |
811 | for (method = authmethods; method->name != NULL; method++) | |
812 | if (strcmp(name, method->name) == 0) | |
813 | return method; | |
814 | debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); | |
815 | return NULL; | |
816 | } | |
817 | ||
cab80f75 | 818 | /* XXX internal state */ |
819 | static Authmethod *current = NULL; | |
820 | static char *supported = NULL; | |
821 | static char *preferred = NULL; | |
188adeb2 | 822 | /* |
823 | * Given the authentication method list sent by the server, return the | |
824 | * next method we should try. If the server initially sends a nil list, | |
cab80f75 | 825 | * use a built-in default list. |
2b87da3b | 826 | */ |
188adeb2 | 827 | Authmethod * |
828 | authmethod_get(char *authlist) | |
829 | { | |
cab80f75 | 830 | |
831 | char *name = NULL; | |
832 | int next; | |
2b87da3b | 833 | |
188adeb2 | 834 | /* Use a suitable default if we're passed a nil list. */ |
835 | if (authlist == NULL || strlen(authlist) == 0) | |
cab80f75 | 836 | authlist = options.preferred_authentications; |
837 | ||
838 | if (supported == NULL || strcmp(authlist, supported) != 0) { | |
839 | debug3("start over, passed a different list %s", authlist); | |
840 | if (supported != NULL) | |
841 | xfree(supported); | |
842 | supported = xstrdup(authlist); | |
843 | preferred = options.preferred_authentications; | |
844 | debug3("preferred %s", preferred); | |
845 | current = NULL; | |
846 | } else if (current != NULL && authmethod_is_enabled(current)) | |
847 | return current; | |
188adeb2 | 848 | |
cab80f75 | 849 | for (;;) { |
850 | if ((name = match_list(preferred, supported, &next)) == NULL) { | |
851 | debug("no more auth methods to try"); | |
852 | current = NULL; | |
853 | return NULL; | |
854 | } | |
855 | preferred += next; | |
94ec8c6b | 856 | debug3("authmethod_lookup %s", name); |
cab80f75 | 857 | debug3("remaining preferred: %s", preferred); |
858 | if ((current = authmethod_lookup(name)) != NULL && | |
859 | authmethod_is_enabled(current)) { | |
94ec8c6b | 860 | debug3("authmethod_is_enabled %s", name); |
cab80f75 | 861 | debug("next auth method to try is %s", name); |
862 | return current; | |
94ec8c6b | 863 | } |
a306f2dd | 864 | } |
cab80f75 | 865 | } |
a22aff1f | 866 | |
a22aff1f | 867 | |
cab80f75 | 868 | #define DELIM "," |
869 | char * | |
870 | authmethods_get(void) | |
871 | { | |
872 | Authmethod *method = NULL; | |
873 | char buf[1024]; | |
874 | ||
875 | buf[0] = '\0'; | |
876 | for (method = authmethods; method->name != NULL; method++) { | |
877 | if (authmethod_is_enabled(method)) { | |
878 | if (buf[0] != '\0') | |
879 | strlcat(buf, DELIM, sizeof buf); | |
880 | strlcat(buf, method->name, sizeof buf); | |
881 | } | |
882 | } | |
883 | return xstrdup(buf); | |
a306f2dd | 884 | } |