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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" | |
396c147e | 26 | RCSID("$OpenBSD: sshconnect2.c,v 1.76 2001/06/23 15:12:21 itojun 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" |
8002af61 | 56 | #include "canohost.h" |
94ec8c6b | 57 | |
a306f2dd | 58 | /* import */ |
59 | extern char *client_version_string; | |
60 | extern char *server_version_string; | |
61 | extern Options options; | |
62 | ||
63 | /* | |
64 | * SSH2 key exchange | |
65 | */ | |
66 | ||
1e3b8b07 | 67 | u_char *session_id2 = NULL; |
a306f2dd | 68 | int session_id2_len = 0; |
69 | ||
a5c9ffdb | 70 | char *xxx_host; |
71 | struct sockaddr *xxx_hostaddr; | |
72 | ||
e092ce67 | 73 | Kex *xxx_kex = NULL; |
74 | ||
396c147e | 75 | static int |
f49bc4f7 | 76 | verify_host_key_callback(Key *hostkey) |
a5c9ffdb | 77 | { |
f49bc4f7 | 78 | if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1) |
79 | fatal("verify_host_key failed"); | |
a5c9ffdb | 80 | return 0; |
81 | } | |
82 | ||
a306f2dd | 83 | void |
94ec8c6b | 84 | ssh_kex2(char *host, struct sockaddr *hostaddr) |
85 | { | |
94ec8c6b | 86 | Kex *kex; |
a5c9ffdb | 87 | |
88 | xxx_host = host; | |
89 | xxx_hostaddr = hostaddr; | |
94ec8c6b | 90 | |
c523303b | 91 | if (options.ciphers == (char *)-1) { |
92 | log("No valid ciphers for protocol version 2 given, using defaults."); | |
93 | options.ciphers = NULL; | |
94ec8c6b | 94 | } |
95 | if (options.ciphers != NULL) { | |
96 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = | |
97 | myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; | |
98 | } | |
1ad64a93 | 99 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = |
100 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); | |
101 | myproposal[PROPOSAL_ENC_ALGS_STOC] = | |
102 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); | |
94ec8c6b | 103 | if (options.compression) { |
b2552997 | 104 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = |
94ec8c6b | 105 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib"; |
106 | } else { | |
b2552997 | 107 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = |
94ec8c6b | 108 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none"; |
109 | } | |
b2552997 | 110 | if (options.macs != NULL) { |
111 | myproposal[PROPOSAL_MAC_ALGS_CTOS] = | |
112 | myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; | |
113 | } | |
e961a8f9 | 114 | if (options.hostkeyalgorithms != NULL) |
115 | myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = | |
116 | options.hostkeyalgorithms; | |
94ec8c6b | 117 | |
7a37c112 | 118 | /* start key exchange */ |
d8ee838b | 119 | kex = kex_setup(myproposal); |
a5c9ffdb | 120 | kex->client_version_string=client_version_string; |
121 | kex->server_version_string=server_version_string; | |
f49bc4f7 | 122 | kex->verify_host_key=&verify_host_key_callback; |
94ec8c6b | 123 | |
e092ce67 | 124 | xxx_kex = kex; |
125 | ||
c422989b | 126 | dispatch_run(DISPATCH_BLOCK, &kex->done, kex); |
94ec8c6b | 127 | |
d1ac6175 | 128 | session_id2 = kex->session_id; |
129 | session_id2_len = kex->session_id_len; | |
130 | ||
94ec8c6b | 131 | #ifdef DEBUG_KEXDH |
132 | /* send 1st encrypted/maced/compressed message */ | |
133 | packet_start(SSH2_MSG_IGNORE); | |
134 | packet_put_cstring("markus"); | |
135 | packet_send(); | |
136 | packet_write_wait(); | |
137 | #endif | |
a5c9ffdb | 138 | debug("done: ssh_kex2."); |
a306f2dd | 139 | } |
71276795 | 140 | |
a306f2dd | 141 | /* |
142 | * Authenticate user | |
143 | */ | |
188adeb2 | 144 | |
145 | typedef struct Authctxt Authctxt; | |
146 | typedef struct Authmethod Authmethod; | |
147 | ||
148 | typedef int sign_cb_fn( | |
149 | Authctxt *authctxt, Key *key, | |
1e3b8b07 | 150 | u_char **sigp, int *lenp, u_char *data, int datalen); |
188adeb2 | 151 | |
152 | struct Authctxt { | |
153 | const char *server_user; | |
8002af61 | 154 | const char *local_user; |
188adeb2 | 155 | const char *host; |
156 | const char *service; | |
188adeb2 | 157 | Authmethod *method; |
94ec8c6b | 158 | int success; |
fee56204 | 159 | char *authlist; |
8002af61 | 160 | /* pubkey */ |
fee56204 | 161 | Key *last_key; |
162 | sign_cb_fn *last_key_sign; | |
163 | int last_key_hint; | |
8002af61 | 164 | AuthenticationConnection *agent; |
165 | /* hostbased */ | |
166 | Key **keys; | |
167 | int nkeys; | |
188adeb2 | 168 | }; |
169 | struct Authmethod { | |
170 | char *name; /* string to compare against server's list */ | |
171 | int (*userauth)(Authctxt *authctxt); | |
172 | int *enabled; /* flag in option struct that enables method */ | |
173 | int *batch_flag; /* flag in option struct that disables method */ | |
174 | }; | |
175 | ||
176 | void input_userauth_success(int type, int plen, void *ctxt); | |
177 | void input_userauth_failure(int type, int plen, void *ctxt); | |
9616313f | 178 | void input_userauth_banner(int type, int plen, void *ctxt); |
188adeb2 | 179 | void input_userauth_error(int type, int plen, void *ctxt); |
94ec8c6b | 180 | void input_userauth_info_req(int type, int plen, void *ctxt); |
fee56204 | 181 | void input_userauth_pk_ok(int type, int plen, void *ctxt); |
94ec8c6b | 182 | |
183 | int userauth_none(Authctxt *authctxt); | |
188adeb2 | 184 | int userauth_pubkey(Authctxt *authctxt); |
185 | int userauth_passwd(Authctxt *authctxt); | |
94ec8c6b | 186 | int userauth_kbdint(Authctxt *authctxt); |
8002af61 | 187 | int userauth_hostbased(Authctxt *authctxt); |
188adeb2 | 188 | |
fee56204 | 189 | void userauth(Authctxt *authctxt, char *authlist); |
190 | ||
396c147e | 191 | static int sign_and_send_pubkey(Authctxt *, Key *, sign_cb_fn *); |
192 | static void clear_auth_state(Authctxt *); | |
fee56204 | 193 | |
396c147e | 194 | static Authmethod *authmethod_get(char *authlist); |
195 | static Authmethod *authmethod_lookup(const char *name); | |
196 | static char *authmethods_get(void); | |
188adeb2 | 197 | |
198 | Authmethod authmethods[] = { | |
199 | {"publickey", | |
200 | userauth_pubkey, | |
fa08c86b | 201 | &options.pubkey_authentication, |
188adeb2 | 202 | NULL}, |
3398dda9 | 203 | {"hostbased", |
204 | userauth_hostbased, | |
205 | &options.hostbased_authentication, | |
206 | NULL}, | |
188adeb2 | 207 | {"password", |
208 | userauth_passwd, | |
209 | &options.password_authentication, | |
210 | &options.batch_mode}, | |
94ec8c6b | 211 | {"keyboard-interactive", |
212 | userauth_kbdint, | |
213 | &options.kbd_interactive_authentication, | |
214 | &options.batch_mode}, | |
215 | {"none", | |
216 | userauth_none, | |
217 | NULL, | |
218 | NULL}, | |
188adeb2 | 219 | {NULL, NULL, NULL, NULL} |
220 | }; | |
221 | ||
222 | void | |
8002af61 | 223 | ssh_userauth2(const char *local_user, const char *server_user, char *host, |
224 | Key **keys, int nkeys) | |
188adeb2 | 225 | { |
226 | Authctxt authctxt; | |
227 | int type; | |
228 | int plen; | |
229 | ||
5ba55ada | 230 | if (options.challenge_response_authentication) |
d464095c | 231 | options.kbd_interactive_authentication = 1; |
232 | ||
188adeb2 | 233 | debug("send SSH2_MSG_SERVICE_REQUEST"); |
234 | packet_start(SSH2_MSG_SERVICE_REQUEST); | |
235 | packet_put_cstring("ssh-userauth"); | |
236 | packet_send(); | |
237 | packet_write_wait(); | |
238 | type = packet_read(&plen); | |
239 | if (type != SSH2_MSG_SERVICE_ACCEPT) { | |
240 | fatal("denied SSH2_MSG_SERVICE_ACCEPT: %d", type); | |
241 | } | |
242 | if (packet_remaining() > 0) { | |
243 | char *reply = packet_get_string(&plen); | |
244 | debug("service_accept: %s", reply); | |
245 | xfree(reply); | |
188adeb2 | 246 | } else { |
247 | debug("buggy server: service_accept w/o service"); | |
248 | } | |
249 | packet_done(); | |
250 | debug("got SSH2_MSG_SERVICE_ACCEPT"); | |
251 | ||
cab80f75 | 252 | if (options.preferred_authentications == NULL) |
253 | options.preferred_authentications = authmethods_get(); | |
254 | ||
188adeb2 | 255 | /* setup authentication context */ |
256 | authctxt.agent = ssh_get_authentication_connection(); | |
257 | authctxt.server_user = server_user; | |
8002af61 | 258 | authctxt.local_user = local_user; |
188adeb2 | 259 | authctxt.host = host; |
260 | authctxt.service = "ssh-connection"; /* service name */ | |
261 | authctxt.success = 0; | |
94ec8c6b | 262 | authctxt.method = authmethod_lookup("none"); |
fee56204 | 263 | authctxt.authlist = NULL; |
8002af61 | 264 | authctxt.keys = keys; |
265 | authctxt.nkeys = nkeys; | |
94ec8c6b | 266 | if (authctxt.method == NULL) |
267 | fatal("ssh_userauth2: internal error: cannot send userauth none request"); | |
188adeb2 | 268 | |
269 | /* initial userauth request */ | |
94ec8c6b | 270 | userauth_none(&authctxt); |
188adeb2 | 271 | |
7a37c112 | 272 | dispatch_init(&input_userauth_error); |
188adeb2 | 273 | dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); |
274 | dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure); | |
9616313f | 275 | dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner); |
188adeb2 | 276 | dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */ |
277 | ||
278 | if (authctxt.agent != NULL) | |
279 | ssh_close_authentication_connection(authctxt.agent); | |
280 | ||
8abcdba4 | 281 | debug("ssh-userauth2 successful: method %s", authctxt.method->name); |
188adeb2 | 282 | } |
283 | void | |
fee56204 | 284 | userauth(Authctxt *authctxt, char *authlist) |
285 | { | |
286 | if (authlist == NULL) { | |
287 | authlist = authctxt->authlist; | |
288 | } else { | |
289 | if (authctxt->authlist) | |
290 | xfree(authctxt->authlist); | |
291 | authctxt->authlist = authlist; | |
292 | } | |
293 | for (;;) { | |
294 | Authmethod *method = authmethod_get(authlist); | |
295 | if (method == NULL) | |
296 | fatal("Permission denied (%s).", authlist); | |
297 | authctxt->method = method; | |
298 | if (method->userauth(authctxt) != 0) { | |
299 | debug2("we sent a %s packet, wait for reply", method->name); | |
300 | break; | |
301 | } else { | |
302 | debug2("we did not send a packet, disable method"); | |
303 | method->enabled = NULL; | |
304 | } | |
305 | } | |
306 | } | |
307 | void | |
188adeb2 | 308 | input_userauth_error(int type, int plen, void *ctxt) |
309 | { | |
9616313f | 310 | fatal("input_userauth_error: bad message during authentication: " |
311 | "type %d", type); | |
312 | } | |
313 | void | |
314 | input_userauth_banner(int type, int plen, void *ctxt) | |
315 | { | |
316 | char *msg, *lang; | |
317 | debug3("input_userauth_banner"); | |
318 | msg = packet_get_string(NULL); | |
319 | lang = packet_get_string(NULL); | |
320 | fprintf(stderr, "%s", msg); | |
321 | xfree(msg); | |
322 | xfree(lang); | |
188adeb2 | 323 | } |
324 | void | |
325 | input_userauth_success(int type, int plen, void *ctxt) | |
326 | { | |
327 | Authctxt *authctxt = ctxt; | |
328 | if (authctxt == NULL) | |
329 | fatal("input_userauth_success: no authentication context"); | |
fee56204 | 330 | if (authctxt->authlist) |
331 | xfree(authctxt->authlist); | |
332 | clear_auth_state(authctxt); | |
188adeb2 | 333 | authctxt->success = 1; /* break out */ |
334 | } | |
335 | void | |
336 | input_userauth_failure(int type, int plen, void *ctxt) | |
337 | { | |
188adeb2 | 338 | Authctxt *authctxt = ctxt; |
339 | char *authlist = NULL; | |
340 | int partial; | |
188adeb2 | 341 | |
342 | if (authctxt == NULL) | |
343 | fatal("input_userauth_failure: no authentication context"); | |
344 | ||
94ec8c6b | 345 | authlist = packet_get_string(NULL); |
188adeb2 | 346 | partial = packet_get_char(); |
347 | packet_done(); | |
348 | ||
349 | if (partial != 0) | |
f72e01a5 | 350 | log("Authenticated with partial success."); |
188adeb2 | 351 | debug("authentications that can continue: %s", authlist); |
352 | ||
fee56204 | 353 | clear_auth_state(authctxt); |
354 | userauth(authctxt, authlist); | |
355 | } | |
356 | void | |
357 | input_userauth_pk_ok(int type, int plen, void *ctxt) | |
358 | { | |
359 | Authctxt *authctxt = ctxt; | |
360 | Key *key = NULL; | |
361 | Buffer b; | |
ec1f12d3 | 362 | int alen, blen, sent = 0; |
22138a36 | 363 | char *pkalg, *pkblob, *fp; |
fee56204 | 364 | |
365 | if (authctxt == NULL) | |
366 | fatal("input_userauth_pk_ok: no authentication context"); | |
367 | if (datafellows & SSH_BUG_PKOK) { | |
368 | /* this is similar to SSH_BUG_PKAUTH */ | |
369 | debug2("input_userauth_pk_ok: SSH_BUG_PKOK"); | |
370 | pkblob = packet_get_string(&blen); | |
371 | buffer_init(&b); | |
372 | buffer_append(&b, pkblob, blen); | |
373 | pkalg = buffer_get_string(&b, &alen); | |
374 | buffer_free(&b); | |
375 | } else { | |
376 | pkalg = packet_get_string(&alen); | |
377 | pkblob = packet_get_string(&blen); | |
378 | } | |
379 | packet_done(); | |
380 | ||
381 | debug("input_userauth_pk_ok: pkalg %s blen %d lastkey %p hint %d", | |
382 | pkalg, blen, authctxt->last_key, authctxt->last_key_hint); | |
383 | ||
384 | do { | |
385 | if (authctxt->last_key == NULL || | |
386 | authctxt->last_key_sign == NULL) { | |
387 | debug("no last key or no sign cb"); | |
188adeb2 | 388 | break; |
188adeb2 | 389 | } |
ec1f12d3 | 390 | if (key_type_from_name(pkalg) == KEY_UNSPEC) { |
fee56204 | 391 | debug("unknown pkalg %s", pkalg); |
392 | break; | |
393 | } | |
394 | if ((key = key_from_blob(pkblob, blen)) == NULL) { | |
395 | debug("no key from blob. pkalg %s", pkalg); | |
396 | break; | |
397 | } | |
22138a36 | 398 | fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX); |
399 | debug2("input_userauth_pk_ok: fp %s", fp); | |
400 | xfree(fp); | |
fee56204 | 401 | if (!key_equal(key, authctxt->last_key)) { |
402 | debug("key != last_key"); | |
403 | break; | |
404 | } | |
405 | sent = sign_and_send_pubkey(authctxt, key, | |
406 | authctxt->last_key_sign); | |
407 | } while(0); | |
408 | ||
409 | if (key != NULL) | |
410 | key_free(key); | |
411 | xfree(pkalg); | |
412 | xfree(pkblob); | |
413 | ||
414 | /* unregister */ | |
415 | clear_auth_state(authctxt); | |
416 | dispatch_set(SSH2_MSG_USERAUTH_PK_OK, NULL); | |
417 | ||
418 | /* try another method if we did not send a packet*/ | |
419 | if (sent == 0) | |
420 | userauth(authctxt, NULL); | |
421 | ||
188adeb2 | 422 | } |
423 | ||
94ec8c6b | 424 | int |
425 | userauth_none(Authctxt *authctxt) | |
426 | { | |
427 | /* initial userauth request */ | |
428 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
429 | packet_put_cstring(authctxt->server_user); | |
430 | packet_put_cstring(authctxt->service); | |
431 | packet_put_cstring(authctxt->method->name); | |
432 | packet_send(); | |
94ec8c6b | 433 | return 1; |
434 | } | |
435 | ||
a306f2dd | 436 | int |
188adeb2 | 437 | userauth_passwd(Authctxt *authctxt) |
a306f2dd | 438 | { |
1d1ffb87 | 439 | static int attempt = 0; |
a306f2dd | 440 | char prompt[80]; |
441 | char *password; | |
442 | ||
fa649821 | 443 | if (attempt++ >= options.number_of_password_prompts) |
1d1ffb87 | 444 | return 0; |
445 | ||
fa649821 | 446 | if(attempt != 1) |
447 | error("Permission denied, please try again."); | |
448 | ||
f72e01a5 | 449 | snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ", |
188adeb2 | 450 | authctxt->server_user, authctxt->host); |
a306f2dd | 451 | password = read_passphrase(prompt, 0); |
452 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
188adeb2 | 453 | packet_put_cstring(authctxt->server_user); |
454 | packet_put_cstring(authctxt->service); | |
94ec8c6b | 455 | packet_put_cstring(authctxt->method->name); |
a306f2dd | 456 | packet_put_char(0); |
a6215e53 | 457 | packet_put_cstring(password); |
a306f2dd | 458 | memset(password, 0, strlen(password)); |
459 | xfree(password); | |
a6215e53 | 460 | packet_inject_ignore(64); |
a306f2dd | 461 | packet_send(); |
a306f2dd | 462 | return 1; |
463 | } | |
464 | ||
fee56204 | 465 | void |
466 | clear_auth_state(Authctxt *authctxt) | |
467 | { | |
468 | /* XXX clear authentication state */ | |
469 | if (authctxt->last_key != NULL && authctxt->last_key_hint == -1) { | |
470 | debug3("clear_auth_state: key_free %p", authctxt->last_key); | |
471 | key_free(authctxt->last_key); | |
472 | } | |
473 | authctxt->last_key = NULL; | |
474 | authctxt->last_key_hint = -2; | |
475 | authctxt->last_key_sign = NULL; | |
476 | } | |
477 | ||
396c147e | 478 | static int |
188adeb2 | 479 | sign_and_send_pubkey(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback) |
a306f2dd | 480 | { |
481 | Buffer b; | |
1e3b8b07 | 482 | u_char *blob, *signature; |
a306f2dd | 483 | int bloblen, slen; |
74fc9186 | 484 | int skip = 0; |
2e73a022 | 485 | int ret = -1; |
94ec8c6b | 486 | int have_sig = 1; |
a306f2dd | 487 | |
cbc5abf9 | 488 | debug3("sign_and_send_pubkey"); |
fee56204 | 489 | |
fa08c86b | 490 | if (key_to_blob(k, &blob, &bloblen) == 0) { |
491 | /* we cannot handle this key */ | |
cbc5abf9 | 492 | debug3("sign_and_send_pubkey: cannot handle key"); |
fa08c86b | 493 | return 0; |
494 | } | |
a306f2dd | 495 | /* data to be signed */ |
496 | buffer_init(&b); | |
33de75a3 | 497 | if (datafellows & SSH_OLD_SESSIONID) { |
74fc9186 | 498 | buffer_append(&b, session_id2, session_id2_len); |
2b87da3b | 499 | skip = session_id2_len; |
33de75a3 | 500 | } else { |
501 | buffer_put_string(&b, session_id2, session_id2_len); | |
502 | skip = buffer_len(&b); | |
74fc9186 | 503 | } |
a306f2dd | 504 | buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); |
188adeb2 | 505 | buffer_put_cstring(&b, authctxt->server_user); |
d0c832f3 | 506 | buffer_put_cstring(&b, |
cbc5abf9 | 507 | datafellows & SSH_BUG_PKSERVICE ? |
d0c832f3 | 508 | "ssh-userauth" : |
188adeb2 | 509 | authctxt->service); |
cbc5abf9 | 510 | if (datafellows & SSH_BUG_PKAUTH) { |
511 | buffer_put_char(&b, have_sig); | |
512 | } else { | |
513 | buffer_put_cstring(&b, authctxt->method->name); | |
514 | buffer_put_char(&b, have_sig); | |
2b87da3b | 515 | buffer_put_cstring(&b, key_ssh_name(k)); |
cbc5abf9 | 516 | } |
a306f2dd | 517 | buffer_put_string(&b, blob, bloblen); |
a306f2dd | 518 | |
519 | /* generate signature */ | |
fee56204 | 520 | ret = (*sign_callback)(authctxt, k, &signature, &slen, |
521 | buffer_ptr(&b), buffer_len(&b)); | |
2e73a022 | 522 | if (ret == -1) { |
523 | xfree(blob); | |
524 | buffer_free(&b); | |
525 | return 0; | |
526 | } | |
fa08c86b | 527 | #ifdef DEBUG_PK |
a306f2dd | 528 | buffer_dump(&b); |
529 | #endif | |
cbc5abf9 | 530 | if (datafellows & SSH_BUG_PKSERVICE) { |
d0c832f3 | 531 | buffer_clear(&b); |
532 | buffer_append(&b, session_id2, session_id2_len); | |
fee56204 | 533 | skip = session_id2_len; |
d0c832f3 | 534 | buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); |
188adeb2 | 535 | buffer_put_cstring(&b, authctxt->server_user); |
536 | buffer_put_cstring(&b, authctxt->service); | |
94ec8c6b | 537 | buffer_put_cstring(&b, authctxt->method->name); |
538 | buffer_put_char(&b, have_sig); | |
cbc5abf9 | 539 | if (!(datafellows & SSH_BUG_PKAUTH)) |
2b87da3b | 540 | buffer_put_cstring(&b, key_ssh_name(k)); |
d0c832f3 | 541 | buffer_put_string(&b, blob, bloblen); |
542 | } | |
543 | xfree(blob); | |
fee56204 | 544 | |
a306f2dd | 545 | /* append signature */ |
546 | buffer_put_string(&b, signature, slen); | |
547 | xfree(signature); | |
548 | ||
549 | /* skip session id and packet type */ | |
74fc9186 | 550 | if (buffer_len(&b) < skip + 1) |
188adeb2 | 551 | fatal("userauth_pubkey: internal error"); |
74fc9186 | 552 | buffer_consume(&b, skip + 1); |
a306f2dd | 553 | |
554 | /* put remaining data from buffer into packet */ | |
555 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
556 | packet_put_raw(buffer_ptr(&b), buffer_len(&b)); | |
557 | buffer_free(&b); | |
a306f2dd | 558 | packet_send(); |
2e73a022 | 559 | |
560 | return 1; | |
4c8722d9 | 561 | } |
562 | ||
396c147e | 563 | static int |
fee56204 | 564 | send_pubkey_test(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback, |
565 | int hint) | |
4c8722d9 | 566 | { |
fee56204 | 567 | u_char *blob; |
568 | int bloblen, have_sig = 0; | |
4c8722d9 | 569 | |
fee56204 | 570 | debug3("send_pubkey_test"); |
571 | ||
572 | if (key_to_blob(k, &blob, &bloblen) == 0) { | |
573 | /* we cannot handle this key */ | |
574 | debug3("send_pubkey_test: cannot handle key"); | |
4c8722d9 | 575 | return 0; |
576 | } | |
fee56204 | 577 | /* register callback for USERAUTH_PK_OK message */ |
578 | authctxt->last_key_sign = sign_callback; | |
579 | authctxt->last_key_hint = hint; | |
580 | authctxt->last_key = k; | |
581 | dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok); | |
4c8722d9 | 582 | |
fee56204 | 583 | packet_start(SSH2_MSG_USERAUTH_REQUEST); |
584 | packet_put_cstring(authctxt->server_user); | |
585 | packet_put_cstring(authctxt->service); | |
586 | packet_put_cstring(authctxt->method->name); | |
587 | packet_put_char(have_sig); | |
588 | if (!(datafellows & SSH_BUG_PKAUTH)) | |
589 | packet_put_cstring(key_ssh_name(k)); | |
590 | packet_put_string(blob, bloblen); | |
591 | xfree(blob); | |
592 | packet_send(); | |
593 | return 1; | |
594 | } | |
595 | ||
396c147e | 596 | static Key * |
fee56204 | 597 | load_identity_file(char *filename) |
598 | { | |
599 | Key *private; | |
600 | char prompt[300], *passphrase; | |
aeaa3d9e | 601 | int quit, i; |
d156519a | 602 | struct stat st; |
fee56204 | 603 | |
d156519a | 604 | if (stat(filename, &st) < 0) { |
605 | debug3("no such identity: %s", filename); | |
606 | return NULL; | |
607 | } | |
aeaa3d9e | 608 | private = key_load_private_type(KEY_UNSPEC, filename, "", NULL); |
609 | if (private == NULL) { | |
610 | if (options.batch_mode) | |
fee56204 | 611 | return NULL; |
4c8722d9 | 612 | snprintf(prompt, sizeof prompt, |
fa08c86b | 613 | "Enter passphrase for key '%.100s': ", filename); |
188adeb2 | 614 | for (i = 0; i < options.number_of_password_prompts; i++) { |
615 | passphrase = read_passphrase(prompt, 0); | |
616 | if (strcmp(passphrase, "") != 0) { | |
aeaa3d9e | 617 | private = key_load_private_type(KEY_UNSPEC, filename, |
618 | passphrase, NULL); | |
fee56204 | 619 | quit = 0; |
188adeb2 | 620 | } else { |
621 | debug2("no passphrase given, try next key"); | |
fee56204 | 622 | quit = 1; |
188adeb2 | 623 | } |
624 | memset(passphrase, 0, strlen(passphrase)); | |
625 | xfree(passphrase); | |
aeaa3d9e | 626 | if (private != NULL || quit) |
188adeb2 | 627 | break; |
628 | debug2("bad passphrase given, try again..."); | |
629 | } | |
4c8722d9 | 630 | } |
fee56204 | 631 | return private; |
632 | } | |
633 | ||
396c147e | 634 | static int |
fee56204 | 635 | identity_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp, |
636 | u_char *data, int datalen) | |
637 | { | |
638 | Key *private; | |
639 | int idx, ret; | |
640 | ||
641 | idx = authctxt->last_key_hint; | |
642 | if (idx < 0) | |
643 | return -1; | |
644 | private = load_identity_file(options.identity_files[idx]); | |
645 | if (private == NULL) | |
646 | return -1; | |
647 | ret = key_sign(private, sigp, lenp, data, datalen); | |
648 | key_free(private); | |
2e73a022 | 649 | return ret; |
650 | } | |
651 | ||
396c147e | 652 | static int |
653 | agent_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp, | |
1e3b8b07 | 654 | u_char *data, int datalen) |
2e73a022 | 655 | { |
188adeb2 | 656 | return ssh_agent_sign(authctxt->agent, key, sigp, lenp, data, datalen); |
2e73a022 | 657 | } |
658 | ||
396c147e | 659 | static int |
660 | key_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp, | |
fee56204 | 661 | u_char *data, int datalen) |
662 | { | |
cd332296 | 663 | return key_sign(key, sigp, lenp, data, datalen); |
fee56204 | 664 | } |
665 | ||
396c147e | 666 | static int |
188adeb2 | 667 | userauth_pubkey_agent(Authctxt *authctxt) |
2e73a022 | 668 | { |
669 | static int called = 0; | |
fa08c86b | 670 | int ret = 0; |
2e73a022 | 671 | char *comment; |
672 | Key *k; | |
2e73a022 | 673 | |
674 | if (called == 0) { | |
fa08c86b | 675 | if (ssh_get_num_identities(authctxt->agent, 2) == 0) |
676 | debug2("userauth_pubkey_agent: no keys at all"); | |
188adeb2 | 677 | called = 1; |
2e73a022 | 678 | } |
fa08c86b | 679 | k = ssh_get_next_identity(authctxt->agent, &comment, 2); |
188adeb2 | 680 | if (k == NULL) { |
fa08c86b | 681 | debug2("userauth_pubkey_agent: no more keys"); |
682 | } else { | |
fee56204 | 683 | debug("userauth_pubkey_agent: testing agent key %s", comment); |
fa08c86b | 684 | xfree(comment); |
fee56204 | 685 | ret = send_pubkey_test(authctxt, k, agent_sign_cb, -1); |
686 | if (ret == 0) | |
687 | key_free(k); | |
188adeb2 | 688 | } |
fa08c86b | 689 | if (ret == 0) |
690 | debug2("userauth_pubkey_agent: no message sent"); | |
2e73a022 | 691 | return ret; |
a306f2dd | 692 | } |
693 | ||
188adeb2 | 694 | int |
695 | userauth_pubkey(Authctxt *authctxt) | |
a306f2dd | 696 | { |
188adeb2 | 697 | static int idx = 0; |
698 | int sent = 0; | |
fee56204 | 699 | Key *key; |
700 | char *filename; | |
188adeb2 | 701 | |
fa08c86b | 702 | if (authctxt->agent != NULL) { |
703 | do { | |
704 | sent = userauth_pubkey_agent(authctxt); | |
705 | } while(!sent && authctxt->agent->howmany > 0); | |
706 | } | |
707 | while (!sent && idx < options.num_identity_files) { | |
fee56204 | 708 | key = options.identity_keys[idx]; |
709 | filename = options.identity_files[idx]; | |
710 | if (key == NULL) { | |
711 | debug("try privkey: %s", filename); | |
712 | key = load_identity_file(filename); | |
713 | if (key != NULL) { | |
714 | sent = sign_and_send_pubkey(authctxt, key, | |
715 | key_sign_cb); | |
716 | key_free(key); | |
717 | } | |
718 | } else if (key->type != KEY_RSA1) { | |
719 | debug("try pubkey: %s", filename); | |
720 | sent = send_pubkey_test(authctxt, key, | |
721 | identity_sign_cb, idx); | |
722 | } | |
fa08c86b | 723 | idx++; |
724 | } | |
188adeb2 | 725 | return sent; |
726 | } | |
a306f2dd | 727 | |
94ec8c6b | 728 | /* |
729 | * Send userauth request message specifying keyboard-interactive method. | |
730 | */ | |
731 | int | |
732 | userauth_kbdint(Authctxt *authctxt) | |
733 | { | |
734 | static int attempt = 0; | |
735 | ||
736 | if (attempt++ >= options.number_of_password_prompts) | |
737 | return 0; | |
738 | ||
739 | debug2("userauth_kbdint"); | |
740 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
741 | packet_put_cstring(authctxt->server_user); | |
742 | packet_put_cstring(authctxt->service); | |
743 | packet_put_cstring(authctxt->method->name); | |
744 | packet_put_cstring(""); /* lang */ | |
745 | packet_put_cstring(options.kbd_interactive_devices ? | |
746 | options.kbd_interactive_devices : ""); | |
747 | packet_send(); | |
94ec8c6b | 748 | |
749 | dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req); | |
750 | return 1; | |
751 | } | |
752 | ||
753 | /* | |
f72e01a5 | 754 | * parse INFO_REQUEST, prompt user and send INFO_RESPONSE |
94ec8c6b | 755 | */ |
756 | void | |
757 | input_userauth_info_req(int type, int plen, void *ctxt) | |
758 | { | |
759 | Authctxt *authctxt = ctxt; | |
f72e01a5 | 760 | char *name, *inst, *lang, *prompt, *response; |
1e3b8b07 | 761 | u_int num_prompts, i; |
94ec8c6b | 762 | int echo = 0; |
763 | ||
764 | debug2("input_userauth_info_req"); | |
765 | ||
766 | if (authctxt == NULL) | |
767 | fatal("input_userauth_info_req: no authentication context"); | |
768 | ||
769 | name = packet_get_string(NULL); | |
770 | inst = packet_get_string(NULL); | |
771 | lang = packet_get_string(NULL); | |
94ec8c6b | 772 | if (strlen(name) > 0) |
773 | cli_mesg(name); | |
94ec8c6b | 774 | if (strlen(inst) > 0) |
775 | cli_mesg(inst); | |
f72e01a5 | 776 | xfree(name); |
94ec8c6b | 777 | xfree(inst); |
f72e01a5 | 778 | xfree(lang); |
94ec8c6b | 779 | |
780 | num_prompts = packet_get_int(); | |
781 | /* | |
782 | * Begin to build info response packet based on prompts requested. | |
783 | * We commit to providing the correct number of responses, so if | |
784 | * further on we run into a problem that prevents this, we have to | |
785 | * be sure and clean this up and send a correct error response. | |
786 | */ | |
787 | packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE); | |
788 | packet_put_int(num_prompts); | |
789 | ||
5ba55ada | 790 | debug2("input_userauth_info_req: num_prompts %d", num_prompts); |
94ec8c6b | 791 | for (i = 0; i < num_prompts; i++) { |
792 | prompt = packet_get_string(NULL); | |
793 | echo = packet_get_char(); | |
794 | ||
795 | response = cli_prompt(prompt, echo); | |
796 | ||
a6215e53 | 797 | packet_put_cstring(response); |
94ec8c6b | 798 | memset(response, 0, strlen(response)); |
799 | xfree(response); | |
800 | xfree(prompt); | |
801 | } | |
802 | packet_done(); /* done with parsing incoming message. */ | |
803 | ||
a6215e53 | 804 | packet_inject_ignore(64); |
94ec8c6b | 805 | packet_send(); |
94ec8c6b | 806 | } |
a306f2dd | 807 | |
8002af61 | 808 | /* |
809 | * this will be move to an external program (ssh-keysign) ASAP. ssh-keysign | |
810 | * will be setuid-root and the sbit can be removed from /usr/bin/ssh. | |
811 | */ | |
812 | int | |
813 | userauth_hostbased(Authctxt *authctxt) | |
814 | { | |
815 | Key *private = NULL; | |
816 | Buffer b; | |
817 | u_char *signature, *blob; | |
818 | char *chost, *pkalg, *p; | |
8dddf799 | 819 | const char *service; |
8002af61 | 820 | u_int blen, slen; |
f98c3421 | 821 | int ok, i, len, found = 0; |
8002af61 | 822 | |
823 | p = get_local_name(packet_get_connection_in()); | |
824 | if (p == NULL) { | |
825 | error("userauth_hostbased: cannot get local ipaddr/name"); | |
826 | return 0; | |
827 | } | |
f98c3421 | 828 | len = strlen(p) + 2; |
829 | chost = xmalloc(len); | |
830 | strlcpy(chost, p, len); | |
831 | strlcat(chost, ".", len); | |
8002af61 | 832 | debug2("userauth_hostbased: chost %s", chost); |
833 | /* check for a useful key */ | |
834 | for (i = 0; i < authctxt->nkeys; i++) { | |
835 | private = authctxt->keys[i]; | |
836 | if (private && private->type != KEY_RSA1) { | |
837 | found = 1; | |
838 | /* we take and free the key */ | |
839 | authctxt->keys[i] = NULL; | |
840 | break; | |
841 | } | |
842 | } | |
843 | if (!found) { | |
844 | xfree(chost); | |
845 | return 0; | |
846 | } | |
847 | if (key_to_blob(private, &blob, &blen) == 0) { | |
848 | key_free(private); | |
849 | xfree(chost); | |
850 | return 0; | |
851 | } | |
8dddf799 | 852 | service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" : |
853 | authctxt->service; | |
8002af61 | 854 | pkalg = xstrdup(key_ssh_name(private)); |
855 | buffer_init(&b); | |
8002af61 | 856 | /* construct data */ |
8dddf799 | 857 | buffer_put_string(&b, session_id2, session_id2_len); |
8002af61 | 858 | buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); |
859 | buffer_put_cstring(&b, authctxt->server_user); | |
8dddf799 | 860 | buffer_put_cstring(&b, service); |
8002af61 | 861 | buffer_put_cstring(&b, authctxt->method->name); |
862 | buffer_put_cstring(&b, pkalg); | |
863 | buffer_put_string(&b, blob, blen); | |
864 | buffer_put_cstring(&b, chost); | |
865 | buffer_put_cstring(&b, authctxt->local_user); | |
866 | #ifdef DEBUG_PK | |
867 | buffer_dump(&b); | |
868 | #endif | |
869 | debug2("xxx: chost %s", chost); | |
870 | ok = key_sign(private, &signature, &slen, buffer_ptr(&b), buffer_len(&b)); | |
871 | key_free(private); | |
872 | buffer_free(&b); | |
873 | if (ok != 0) { | |
874 | error("key_sign failed"); | |
875 | xfree(chost); | |
876 | xfree(pkalg); | |
877 | return 0; | |
878 | } | |
879 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
880 | packet_put_cstring(authctxt->server_user); | |
881 | packet_put_cstring(authctxt->service); | |
882 | packet_put_cstring(authctxt->method->name); | |
883 | packet_put_cstring(pkalg); | |
884 | packet_put_string(blob, blen); | |
885 | packet_put_cstring(chost); | |
886 | packet_put_cstring(authctxt->local_user); | |
887 | packet_put_string(signature, slen); | |
888 | memset(signature, 's', slen); | |
889 | xfree(signature); | |
890 | xfree(chost); | |
891 | xfree(pkalg); | |
892 | ||
893 | packet_send(); | |
894 | return 1; | |
895 | } | |
896 | ||
188adeb2 | 897 | /* find auth method */ |
898 | ||
188adeb2 | 899 | /* |
900 | * given auth method name, if configurable options permit this method fill | |
901 | * in auth_ident field and return true, otherwise return false. | |
902 | */ | |
396c147e | 903 | static int |
188adeb2 | 904 | authmethod_is_enabled(Authmethod *method) |
905 | { | |
906 | if (method == NULL) | |
907 | return 0; | |
908 | /* return false if options indicate this method is disabled */ | |
909 | if (method->enabled == NULL || *method->enabled == 0) | |
910 | return 0; | |
911 | /* return false if batch mode is enabled but method needs interactive mode */ | |
912 | if (method->batch_flag != NULL && *method->batch_flag != 0) | |
913 | return 0; | |
914 | return 1; | |
915 | } | |
a306f2dd | 916 | |
396c147e | 917 | static Authmethod * |
188adeb2 | 918 | authmethod_lookup(const char *name) |
919 | { | |
920 | Authmethod *method = NULL; | |
921 | if (name != NULL) | |
922 | for (method = authmethods; method->name != NULL; method++) | |
923 | if (strcmp(name, method->name) == 0) | |
924 | return method; | |
925 | debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); | |
926 | return NULL; | |
927 | } | |
928 | ||
cab80f75 | 929 | /* XXX internal state */ |
930 | static Authmethod *current = NULL; | |
931 | static char *supported = NULL; | |
932 | static char *preferred = NULL; | |
188adeb2 | 933 | /* |
934 | * Given the authentication method list sent by the server, return the | |
935 | * next method we should try. If the server initially sends a nil list, | |
cd332296 | 936 | * use a built-in default list. |
2b87da3b | 937 | */ |
396c147e | 938 | static Authmethod * |
188adeb2 | 939 | authmethod_get(char *authlist) |
940 | { | |
cab80f75 | 941 | |
942 | char *name = NULL; | |
943 | int next; | |
2b87da3b | 944 | |
188adeb2 | 945 | /* Use a suitable default if we're passed a nil list. */ |
946 | if (authlist == NULL || strlen(authlist) == 0) | |
cab80f75 | 947 | authlist = options.preferred_authentications; |
948 | ||
949 | if (supported == NULL || strcmp(authlist, supported) != 0) { | |
950 | debug3("start over, passed a different list %s", authlist); | |
951 | if (supported != NULL) | |
952 | xfree(supported); | |
953 | supported = xstrdup(authlist); | |
954 | preferred = options.preferred_authentications; | |
955 | debug3("preferred %s", preferred); | |
956 | current = NULL; | |
957 | } else if (current != NULL && authmethod_is_enabled(current)) | |
958 | return current; | |
188adeb2 | 959 | |
cab80f75 | 960 | for (;;) { |
961 | if ((name = match_list(preferred, supported, &next)) == NULL) { | |
962 | debug("no more auth methods to try"); | |
963 | current = NULL; | |
964 | return NULL; | |
965 | } | |
966 | preferred += next; | |
94ec8c6b | 967 | debug3("authmethod_lookup %s", name); |
cab80f75 | 968 | debug3("remaining preferred: %s", preferred); |
969 | if ((current = authmethod_lookup(name)) != NULL && | |
970 | authmethod_is_enabled(current)) { | |
94ec8c6b | 971 | debug3("authmethod_is_enabled %s", name); |
cab80f75 | 972 | debug("next auth method to try is %s", name); |
973 | return current; | |
94ec8c6b | 974 | } |
a306f2dd | 975 | } |
cab80f75 | 976 | } |
a22aff1f | 977 | |
a22aff1f | 978 | |
cab80f75 | 979 | #define DELIM "," |
980 | char * | |
981 | authmethods_get(void) | |
982 | { | |
983 | Authmethod *method = NULL; | |
984 | char buf[1024]; | |
985 | ||
986 | buf[0] = '\0'; | |
987 | for (method = authmethods; method->name != NULL; method++) { | |
988 | if (authmethod_is_enabled(method)) { | |
989 | if (buf[0] != '\0') | |
990 | strlcat(buf, DELIM, sizeof buf); | |
991 | strlcat(buf, method->name, sizeof buf); | |
992 | } | |
993 | } | |
994 | return xstrdup(buf); | |
a306f2dd | 995 | } |