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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" | |
383546c4 | 26 | RCSID("$OpenBSD: sshconnect2.c,v 1.80 2001/06/26 20:14:11 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" | |
db1cd2f3 | 48 | #include "dh.h" |
2e73a022 | 49 | #include "authfd.h" |
42f11eb2 | 50 | #include "log.h" |
51 | #include "readconf.h" | |
52 | #include "readpass.h" | |
cab80f75 | 53 | #include "match.h" |
a5c9ffdb | 54 | #include "dispatch.h" |
8002af61 | 55 | #include "canohost.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 | ||
396c147e | 74 | static int |
f49bc4f7 | 75 | verify_host_key_callback(Key *hostkey) |
a5c9ffdb | 76 | { |
f49bc4f7 | 77 | if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1) |
78 | fatal("verify_host_key failed"); | |
a5c9ffdb | 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 | } | |
e961a8f9 | 113 | if (options.hostkeyalgorithms != NULL) |
114 | myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = | |
115 | options.hostkeyalgorithms; | |
94ec8c6b | 116 | |
7a37c112 | 117 | /* start key exchange */ |
d8ee838b | 118 | kex = kex_setup(myproposal); |
a5c9ffdb | 119 | kex->client_version_string=client_version_string; |
120 | kex->server_version_string=server_version_string; | |
f49bc4f7 | 121 | kex->verify_host_key=&verify_host_key_callback; |
94ec8c6b | 122 | |
e092ce67 | 123 | xxx_kex = kex; |
124 | ||
c422989b | 125 | dispatch_run(DISPATCH_BLOCK, &kex->done, kex); |
94ec8c6b | 126 | |
d1ac6175 | 127 | session_id2 = kex->session_id; |
128 | session_id2_len = kex->session_id_len; | |
129 | ||
94ec8c6b | 130 | #ifdef DEBUG_KEXDH |
131 | /* send 1st encrypted/maced/compressed message */ | |
132 | packet_start(SSH2_MSG_IGNORE); | |
133 | packet_put_cstring("markus"); | |
134 | packet_send(); | |
135 | packet_write_wait(); | |
136 | #endif | |
a5c9ffdb | 137 | debug("done: ssh_kex2."); |
a306f2dd | 138 | } |
71276795 | 139 | |
a306f2dd | 140 | /* |
141 | * Authenticate user | |
142 | */ | |
188adeb2 | 143 | |
144 | typedef struct Authctxt Authctxt; | |
145 | typedef struct Authmethod Authmethod; | |
146 | ||
147 | typedef int sign_cb_fn( | |
148 | Authctxt *authctxt, Key *key, | |
1e3b8b07 | 149 | u_char **sigp, int *lenp, u_char *data, int datalen); |
188adeb2 | 150 | |
151 | struct Authctxt { | |
152 | const char *server_user; | |
8002af61 | 153 | const char *local_user; |
188adeb2 | 154 | const char *host; |
155 | const char *service; | |
188adeb2 | 156 | Authmethod *method; |
94ec8c6b | 157 | int success; |
fee56204 | 158 | char *authlist; |
8002af61 | 159 | /* pubkey */ |
fee56204 | 160 | Key *last_key; |
161 | sign_cb_fn *last_key_sign; | |
162 | int last_key_hint; | |
8002af61 | 163 | AuthenticationConnection *agent; |
164 | /* hostbased */ | |
165 | Key **keys; | |
166 | int nkeys; | |
188adeb2 | 167 | }; |
168 | struct Authmethod { | |
169 | char *name; /* string to compare against server's list */ | |
170 | int (*userauth)(Authctxt *authctxt); | |
171 | int *enabled; /* flag in option struct that enables method */ | |
172 | int *batch_flag; /* flag in option struct that disables method */ | |
173 | }; | |
174 | ||
175 | void input_userauth_success(int type, int plen, void *ctxt); | |
176 | void input_userauth_failure(int type, int plen, void *ctxt); | |
9616313f | 177 | void input_userauth_banner(int type, int plen, void *ctxt); |
188adeb2 | 178 | void input_userauth_error(int type, int plen, void *ctxt); |
94ec8c6b | 179 | void input_userauth_info_req(int type, int plen, void *ctxt); |
fee56204 | 180 | void input_userauth_pk_ok(int type, int plen, void *ctxt); |
94ec8c6b | 181 | |
182 | int userauth_none(Authctxt *authctxt); | |
188adeb2 | 183 | int userauth_pubkey(Authctxt *authctxt); |
184 | int userauth_passwd(Authctxt *authctxt); | |
94ec8c6b | 185 | int userauth_kbdint(Authctxt *authctxt); |
8002af61 | 186 | int userauth_hostbased(Authctxt *authctxt); |
188adeb2 | 187 | |
fee56204 | 188 | void userauth(Authctxt *authctxt, char *authlist); |
189 | ||
396c147e | 190 | static int sign_and_send_pubkey(Authctxt *, Key *, sign_cb_fn *); |
191 | static void clear_auth_state(Authctxt *); | |
fee56204 | 192 | |
396c147e | 193 | static Authmethod *authmethod_get(char *authlist); |
194 | static Authmethod *authmethod_lookup(const char *name); | |
195 | static char *authmethods_get(void); | |
188adeb2 | 196 | |
197 | Authmethod authmethods[] = { | |
198 | {"publickey", | |
199 | userauth_pubkey, | |
fa08c86b | 200 | &options.pubkey_authentication, |
188adeb2 | 201 | NULL}, |
3398dda9 | 202 | {"hostbased", |
203 | userauth_hostbased, | |
204 | &options.hostbased_authentication, | |
205 | NULL}, | |
188adeb2 | 206 | {"password", |
207 | userauth_passwd, | |
208 | &options.password_authentication, | |
209 | &options.batch_mode}, | |
94ec8c6b | 210 | {"keyboard-interactive", |
211 | userauth_kbdint, | |
212 | &options.kbd_interactive_authentication, | |
213 | &options.batch_mode}, | |
214 | {"none", | |
215 | userauth_none, | |
216 | NULL, | |
217 | NULL}, | |
188adeb2 | 218 | {NULL, NULL, NULL, NULL} |
219 | }; | |
220 | ||
221 | void | |
8002af61 | 222 | ssh_userauth2(const char *local_user, const char *server_user, char *host, |
223 | Key **keys, int nkeys) | |
188adeb2 | 224 | { |
225 | Authctxt authctxt; | |
226 | int type; | |
227 | int plen; | |
228 | ||
5ba55ada | 229 | if (options.challenge_response_authentication) |
d464095c | 230 | options.kbd_interactive_authentication = 1; |
231 | ||
188adeb2 | 232 | debug("send SSH2_MSG_SERVICE_REQUEST"); |
233 | packet_start(SSH2_MSG_SERVICE_REQUEST); | |
234 | packet_put_cstring("ssh-userauth"); | |
235 | packet_send(); | |
236 | packet_write_wait(); | |
237 | type = packet_read(&plen); | |
238 | if (type != SSH2_MSG_SERVICE_ACCEPT) { | |
239 | fatal("denied SSH2_MSG_SERVICE_ACCEPT: %d", type); | |
240 | } | |
241 | if (packet_remaining() > 0) { | |
242 | char *reply = packet_get_string(&plen); | |
243 | debug("service_accept: %s", reply); | |
244 | xfree(reply); | |
188adeb2 | 245 | } else { |
246 | debug("buggy server: service_accept w/o service"); | |
247 | } | |
248 | packet_done(); | |
249 | debug("got SSH2_MSG_SERVICE_ACCEPT"); | |
250 | ||
cab80f75 | 251 | if (options.preferred_authentications == NULL) |
252 | options.preferred_authentications = authmethods_get(); | |
253 | ||
188adeb2 | 254 | /* setup authentication context */ |
255 | authctxt.agent = ssh_get_authentication_connection(); | |
256 | authctxt.server_user = server_user; | |
8002af61 | 257 | authctxt.local_user = local_user; |
188adeb2 | 258 | authctxt.host = host; |
259 | authctxt.service = "ssh-connection"; /* service name */ | |
260 | authctxt.success = 0; | |
94ec8c6b | 261 | authctxt.method = authmethod_lookup("none"); |
fee56204 | 262 | authctxt.authlist = NULL; |
8002af61 | 263 | authctxt.keys = keys; |
264 | authctxt.nkeys = nkeys; | |
94ec8c6b | 265 | if (authctxt.method == NULL) |
266 | fatal("ssh_userauth2: internal error: cannot send userauth none request"); | |
188adeb2 | 267 | |
268 | /* initial userauth request */ | |
94ec8c6b | 269 | userauth_none(&authctxt); |
188adeb2 | 270 | |
7a37c112 | 271 | dispatch_init(&input_userauth_error); |
188adeb2 | 272 | dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); |
273 | dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure); | |
9616313f | 274 | dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner); |
188adeb2 | 275 | dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */ |
276 | ||
277 | if (authctxt.agent != NULL) | |
278 | ssh_close_authentication_connection(authctxt.agent); | |
279 | ||
8abcdba4 | 280 | debug("ssh-userauth2 successful: method %s", authctxt.method->name); |
188adeb2 | 281 | } |
282 | void | |
fee56204 | 283 | userauth(Authctxt *authctxt, char *authlist) |
284 | { | |
285 | if (authlist == NULL) { | |
286 | authlist = authctxt->authlist; | |
287 | } else { | |
288 | if (authctxt->authlist) | |
289 | xfree(authctxt->authlist); | |
290 | authctxt->authlist = authlist; | |
291 | } | |
292 | for (;;) { | |
293 | Authmethod *method = authmethod_get(authlist); | |
294 | if (method == NULL) | |
295 | fatal("Permission denied (%s).", authlist); | |
296 | authctxt->method = method; | |
297 | if (method->userauth(authctxt) != 0) { | |
298 | debug2("we sent a %s packet, wait for reply", method->name); | |
299 | break; | |
300 | } else { | |
301 | debug2("we did not send a packet, disable method"); | |
302 | method->enabled = NULL; | |
303 | } | |
304 | } | |
305 | } | |
306 | void | |
188adeb2 | 307 | input_userauth_error(int type, int plen, void *ctxt) |
308 | { | |
9616313f | 309 | fatal("input_userauth_error: bad message during authentication: " |
310 | "type %d", type); | |
311 | } | |
312 | void | |
313 | input_userauth_banner(int type, int plen, void *ctxt) | |
314 | { | |
315 | char *msg, *lang; | |
316 | debug3("input_userauth_banner"); | |
317 | msg = packet_get_string(NULL); | |
318 | lang = packet_get_string(NULL); | |
319 | fprintf(stderr, "%s", msg); | |
320 | xfree(msg); | |
321 | xfree(lang); | |
188adeb2 | 322 | } |
323 | void | |
324 | input_userauth_success(int type, int plen, void *ctxt) | |
325 | { | |
326 | Authctxt *authctxt = ctxt; | |
327 | if (authctxt == NULL) | |
328 | fatal("input_userauth_success: no authentication context"); | |
fee56204 | 329 | if (authctxt->authlist) |
330 | xfree(authctxt->authlist); | |
331 | clear_auth_state(authctxt); | |
188adeb2 | 332 | authctxt->success = 1; /* break out */ |
333 | } | |
334 | void | |
335 | input_userauth_failure(int type, int plen, void *ctxt) | |
336 | { | |
188adeb2 | 337 | Authctxt *authctxt = ctxt; |
338 | char *authlist = NULL; | |
339 | int partial; | |
188adeb2 | 340 | |
341 | if (authctxt == NULL) | |
342 | fatal("input_userauth_failure: no authentication context"); | |
343 | ||
94ec8c6b | 344 | authlist = packet_get_string(NULL); |
188adeb2 | 345 | partial = packet_get_char(); |
346 | packet_done(); | |
347 | ||
348 | if (partial != 0) | |
f72e01a5 | 349 | log("Authenticated with partial success."); |
188adeb2 | 350 | debug("authentications that can continue: %s", authlist); |
351 | ||
fee56204 | 352 | clear_auth_state(authctxt); |
353 | userauth(authctxt, authlist); | |
354 | } | |
355 | void | |
356 | input_userauth_pk_ok(int type, int plen, void *ctxt) | |
357 | { | |
358 | Authctxt *authctxt = ctxt; | |
359 | Key *key = NULL; | |
360 | Buffer b; | |
ec1f12d3 | 361 | int alen, blen, sent = 0; |
22138a36 | 362 | char *pkalg, *pkblob, *fp; |
fee56204 | 363 | |
364 | if (authctxt == NULL) | |
365 | fatal("input_userauth_pk_ok: no authentication context"); | |
366 | if (datafellows & SSH_BUG_PKOK) { | |
367 | /* this is similar to SSH_BUG_PKAUTH */ | |
368 | debug2("input_userauth_pk_ok: SSH_BUG_PKOK"); | |
369 | pkblob = packet_get_string(&blen); | |
370 | buffer_init(&b); | |
371 | buffer_append(&b, pkblob, blen); | |
372 | pkalg = buffer_get_string(&b, &alen); | |
373 | buffer_free(&b); | |
374 | } else { | |
375 | pkalg = packet_get_string(&alen); | |
376 | pkblob = packet_get_string(&blen); | |
377 | } | |
378 | packet_done(); | |
379 | ||
380 | debug("input_userauth_pk_ok: pkalg %s blen %d lastkey %p hint %d", | |
381 | pkalg, blen, authctxt->last_key, authctxt->last_key_hint); | |
382 | ||
383 | do { | |
384 | if (authctxt->last_key == NULL || | |
385 | authctxt->last_key_sign == NULL) { | |
386 | debug("no last key or no sign cb"); | |
188adeb2 | 387 | break; |
188adeb2 | 388 | } |
ec1f12d3 | 389 | if (key_type_from_name(pkalg) == KEY_UNSPEC) { |
fee56204 | 390 | debug("unknown pkalg %s", pkalg); |
391 | break; | |
392 | } | |
393 | if ((key = key_from_blob(pkblob, blen)) == NULL) { | |
394 | debug("no key from blob. pkalg %s", pkalg); | |
395 | break; | |
396 | } | |
22138a36 | 397 | fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX); |
398 | debug2("input_userauth_pk_ok: fp %s", fp); | |
399 | xfree(fp); | |
fee56204 | 400 | if (!key_equal(key, authctxt->last_key)) { |
401 | debug("key != last_key"); | |
402 | break; | |
403 | } | |
404 | sent = sign_and_send_pubkey(authctxt, key, | |
405 | authctxt->last_key_sign); | |
406 | } while(0); | |
407 | ||
408 | if (key != NULL) | |
409 | key_free(key); | |
410 | xfree(pkalg); | |
411 | xfree(pkblob); | |
412 | ||
413 | /* unregister */ | |
414 | clear_auth_state(authctxt); | |
415 | dispatch_set(SSH2_MSG_USERAUTH_PK_OK, NULL); | |
416 | ||
417 | /* try another method if we did not send a packet*/ | |
418 | if (sent == 0) | |
419 | userauth(authctxt, NULL); | |
420 | ||
188adeb2 | 421 | } |
422 | ||
94ec8c6b | 423 | int |
424 | userauth_none(Authctxt *authctxt) | |
425 | { | |
426 | /* initial userauth request */ | |
427 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
428 | packet_put_cstring(authctxt->server_user); | |
429 | packet_put_cstring(authctxt->service); | |
430 | packet_put_cstring(authctxt->method->name); | |
431 | packet_send(); | |
94ec8c6b | 432 | return 1; |
433 | } | |
434 | ||
a306f2dd | 435 | int |
188adeb2 | 436 | userauth_passwd(Authctxt *authctxt) |
a306f2dd | 437 | { |
1d1ffb87 | 438 | static int attempt = 0; |
a306f2dd | 439 | char prompt[80]; |
440 | char *password; | |
441 | ||
fa649821 | 442 | if (attempt++ >= options.number_of_password_prompts) |
1d1ffb87 | 443 | return 0; |
444 | ||
fa649821 | 445 | if(attempt != 1) |
446 | error("Permission denied, please try again."); | |
447 | ||
f72e01a5 | 448 | snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ", |
188adeb2 | 449 | authctxt->server_user, authctxt->host); |
a306f2dd | 450 | password = read_passphrase(prompt, 0); |
451 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
188adeb2 | 452 | packet_put_cstring(authctxt->server_user); |
453 | packet_put_cstring(authctxt->service); | |
94ec8c6b | 454 | packet_put_cstring(authctxt->method->name); |
a306f2dd | 455 | packet_put_char(0); |
a6215e53 | 456 | packet_put_cstring(password); |
a306f2dd | 457 | memset(password, 0, strlen(password)); |
458 | xfree(password); | |
a6215e53 | 459 | packet_inject_ignore(64); |
a306f2dd | 460 | packet_send(); |
a306f2dd | 461 | return 1; |
462 | } | |
463 | ||
ffb215be | 464 | static void |
fee56204 | 465 | clear_auth_state(Authctxt *authctxt) |
466 | { | |
467 | /* XXX clear authentication state */ | |
468 | if (authctxt->last_key != NULL && authctxt->last_key_hint == -1) { | |
469 | debug3("clear_auth_state: key_free %p", authctxt->last_key); | |
470 | key_free(authctxt->last_key); | |
471 | } | |
472 | authctxt->last_key = NULL; | |
473 | authctxt->last_key_hint = -2; | |
474 | authctxt->last_key_sign = NULL; | |
475 | } | |
476 | ||
396c147e | 477 | static int |
188adeb2 | 478 | sign_and_send_pubkey(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback) |
a306f2dd | 479 | { |
480 | Buffer b; | |
1e3b8b07 | 481 | u_char *blob, *signature; |
a306f2dd | 482 | int bloblen, slen; |
74fc9186 | 483 | int skip = 0; |
2e73a022 | 484 | int ret = -1; |
94ec8c6b | 485 | int have_sig = 1; |
a306f2dd | 486 | |
cbc5abf9 | 487 | debug3("sign_and_send_pubkey"); |
fee56204 | 488 | |
fa08c86b | 489 | if (key_to_blob(k, &blob, &bloblen) == 0) { |
490 | /* we cannot handle this key */ | |
cbc5abf9 | 491 | debug3("sign_and_send_pubkey: cannot handle key"); |
fa08c86b | 492 | return 0; |
493 | } | |
a306f2dd | 494 | /* data to be signed */ |
495 | buffer_init(&b); | |
33de75a3 | 496 | if (datafellows & SSH_OLD_SESSIONID) { |
74fc9186 | 497 | buffer_append(&b, session_id2, session_id2_len); |
2b87da3b | 498 | skip = session_id2_len; |
33de75a3 | 499 | } else { |
500 | buffer_put_string(&b, session_id2, session_id2_len); | |
501 | skip = buffer_len(&b); | |
74fc9186 | 502 | } |
a306f2dd | 503 | buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); |
188adeb2 | 504 | buffer_put_cstring(&b, authctxt->server_user); |
d0c832f3 | 505 | buffer_put_cstring(&b, |
cbc5abf9 | 506 | datafellows & SSH_BUG_PKSERVICE ? |
d0c832f3 | 507 | "ssh-userauth" : |
188adeb2 | 508 | authctxt->service); |
cbc5abf9 | 509 | if (datafellows & SSH_BUG_PKAUTH) { |
510 | buffer_put_char(&b, have_sig); | |
511 | } else { | |
512 | buffer_put_cstring(&b, authctxt->method->name); | |
513 | buffer_put_char(&b, have_sig); | |
2b87da3b | 514 | buffer_put_cstring(&b, key_ssh_name(k)); |
cbc5abf9 | 515 | } |
a306f2dd | 516 | buffer_put_string(&b, blob, bloblen); |
a306f2dd | 517 | |
518 | /* generate signature */ | |
fee56204 | 519 | ret = (*sign_callback)(authctxt, k, &signature, &slen, |
520 | buffer_ptr(&b), buffer_len(&b)); | |
2e73a022 | 521 | if (ret == -1) { |
522 | xfree(blob); | |
523 | buffer_free(&b); | |
524 | return 0; | |
525 | } | |
fa08c86b | 526 | #ifdef DEBUG_PK |
a306f2dd | 527 | buffer_dump(&b); |
528 | #endif | |
cbc5abf9 | 529 | if (datafellows & SSH_BUG_PKSERVICE) { |
d0c832f3 | 530 | buffer_clear(&b); |
531 | buffer_append(&b, session_id2, session_id2_len); | |
fee56204 | 532 | skip = session_id2_len; |
d0c832f3 | 533 | buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); |
188adeb2 | 534 | buffer_put_cstring(&b, authctxt->server_user); |
535 | buffer_put_cstring(&b, authctxt->service); | |
94ec8c6b | 536 | buffer_put_cstring(&b, authctxt->method->name); |
537 | buffer_put_char(&b, have_sig); | |
cbc5abf9 | 538 | if (!(datafellows & SSH_BUG_PKAUTH)) |
2b87da3b | 539 | buffer_put_cstring(&b, key_ssh_name(k)); |
d0c832f3 | 540 | buffer_put_string(&b, blob, bloblen); |
541 | } | |
542 | xfree(blob); | |
fee56204 | 543 | |
a306f2dd | 544 | /* append signature */ |
545 | buffer_put_string(&b, signature, slen); | |
546 | xfree(signature); | |
547 | ||
548 | /* skip session id and packet type */ | |
74fc9186 | 549 | if (buffer_len(&b) < skip + 1) |
188adeb2 | 550 | fatal("userauth_pubkey: internal error"); |
74fc9186 | 551 | buffer_consume(&b, skip + 1); |
a306f2dd | 552 | |
553 | /* put remaining data from buffer into packet */ | |
554 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
555 | packet_put_raw(buffer_ptr(&b), buffer_len(&b)); | |
556 | buffer_free(&b); | |
a306f2dd | 557 | packet_send(); |
2e73a022 | 558 | |
559 | return 1; | |
4c8722d9 | 560 | } |
561 | ||
396c147e | 562 | static int |
fee56204 | 563 | send_pubkey_test(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback, |
564 | int hint) | |
4c8722d9 | 565 | { |
fee56204 | 566 | u_char *blob; |
567 | int bloblen, have_sig = 0; | |
4c8722d9 | 568 | |
fee56204 | 569 | debug3("send_pubkey_test"); |
570 | ||
571 | if (key_to_blob(k, &blob, &bloblen) == 0) { | |
572 | /* we cannot handle this key */ | |
573 | debug3("send_pubkey_test: cannot handle key"); | |
4c8722d9 | 574 | return 0; |
575 | } | |
fee56204 | 576 | /* register callback for USERAUTH_PK_OK message */ |
577 | authctxt->last_key_sign = sign_callback; | |
578 | authctxt->last_key_hint = hint; | |
579 | authctxt->last_key = k; | |
580 | dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok); | |
4c8722d9 | 581 | |
fee56204 | 582 | packet_start(SSH2_MSG_USERAUTH_REQUEST); |
583 | packet_put_cstring(authctxt->server_user); | |
584 | packet_put_cstring(authctxt->service); | |
585 | packet_put_cstring(authctxt->method->name); | |
586 | packet_put_char(have_sig); | |
587 | if (!(datafellows & SSH_BUG_PKAUTH)) | |
588 | packet_put_cstring(key_ssh_name(k)); | |
589 | packet_put_string(blob, bloblen); | |
590 | xfree(blob); | |
591 | packet_send(); | |
592 | return 1; | |
593 | } | |
594 | ||
396c147e | 595 | static Key * |
fee56204 | 596 | load_identity_file(char *filename) |
597 | { | |
598 | Key *private; | |
599 | char prompt[300], *passphrase; | |
aeaa3d9e | 600 | int quit, i; |
d156519a | 601 | struct stat st; |
fee56204 | 602 | |
d156519a | 603 | if (stat(filename, &st) < 0) { |
604 | debug3("no such identity: %s", filename); | |
605 | return NULL; | |
606 | } | |
aeaa3d9e | 607 | private = key_load_private_type(KEY_UNSPEC, filename, "", NULL); |
608 | if (private == NULL) { | |
609 | if (options.batch_mode) | |
fee56204 | 610 | return NULL; |
4c8722d9 | 611 | snprintf(prompt, sizeof prompt, |
fa08c86b | 612 | "Enter passphrase for key '%.100s': ", filename); |
188adeb2 | 613 | for (i = 0; i < options.number_of_password_prompts; i++) { |
614 | passphrase = read_passphrase(prompt, 0); | |
615 | if (strcmp(passphrase, "") != 0) { | |
aeaa3d9e | 616 | private = key_load_private_type(KEY_UNSPEC, filename, |
617 | passphrase, NULL); | |
fee56204 | 618 | quit = 0; |
188adeb2 | 619 | } else { |
620 | debug2("no passphrase given, try next key"); | |
fee56204 | 621 | quit = 1; |
188adeb2 | 622 | } |
623 | memset(passphrase, 0, strlen(passphrase)); | |
624 | xfree(passphrase); | |
aeaa3d9e | 625 | if (private != NULL || quit) |
188adeb2 | 626 | break; |
627 | debug2("bad passphrase given, try again..."); | |
628 | } | |
4c8722d9 | 629 | } |
fee56204 | 630 | return private; |
631 | } | |
632 | ||
396c147e | 633 | static int |
fee56204 | 634 | identity_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp, |
635 | u_char *data, int datalen) | |
636 | { | |
637 | Key *private; | |
638 | int idx, ret; | |
639 | ||
640 | idx = authctxt->last_key_hint; | |
641 | if (idx < 0) | |
642 | return -1; | |
383546c4 | 643 | |
644 | /* private key is stored in external hardware */ | |
645 | if (options.identity_keys[idx]->flags & KEY_FLAG_EXT) | |
646 | return key_sign(options.identity_keys[idx], sigp, lenp, data, datalen); | |
647 | ||
fee56204 | 648 | private = load_identity_file(options.identity_files[idx]); |
649 | if (private == NULL) | |
650 | return -1; | |
651 | ret = key_sign(private, sigp, lenp, data, datalen); | |
652 | key_free(private); | |
2e73a022 | 653 | return ret; |
654 | } | |
655 | ||
396c147e | 656 | static int |
657 | agent_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp, | |
1e3b8b07 | 658 | u_char *data, int datalen) |
2e73a022 | 659 | { |
188adeb2 | 660 | return ssh_agent_sign(authctxt->agent, key, sigp, lenp, data, datalen); |
2e73a022 | 661 | } |
662 | ||
396c147e | 663 | static int |
664 | key_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, int *lenp, | |
fee56204 | 665 | u_char *data, int datalen) |
666 | { | |
cd332296 | 667 | return key_sign(key, sigp, lenp, data, datalen); |
fee56204 | 668 | } |
669 | ||
396c147e | 670 | static int |
188adeb2 | 671 | userauth_pubkey_agent(Authctxt *authctxt) |
2e73a022 | 672 | { |
673 | static int called = 0; | |
fa08c86b | 674 | int ret = 0; |
2e73a022 | 675 | char *comment; |
676 | Key *k; | |
2e73a022 | 677 | |
678 | if (called == 0) { | |
fa08c86b | 679 | if (ssh_get_num_identities(authctxt->agent, 2) == 0) |
680 | debug2("userauth_pubkey_agent: no keys at all"); | |
188adeb2 | 681 | called = 1; |
2e73a022 | 682 | } |
fa08c86b | 683 | k = ssh_get_next_identity(authctxt->agent, &comment, 2); |
188adeb2 | 684 | if (k == NULL) { |
fa08c86b | 685 | debug2("userauth_pubkey_agent: no more keys"); |
686 | } else { | |
fee56204 | 687 | debug("userauth_pubkey_agent: testing agent key %s", comment); |
fa08c86b | 688 | xfree(comment); |
fee56204 | 689 | ret = send_pubkey_test(authctxt, k, agent_sign_cb, -1); |
690 | if (ret == 0) | |
691 | key_free(k); | |
188adeb2 | 692 | } |
fa08c86b | 693 | if (ret == 0) |
694 | debug2("userauth_pubkey_agent: no message sent"); | |
2e73a022 | 695 | return ret; |
a306f2dd | 696 | } |
697 | ||
188adeb2 | 698 | int |
699 | userauth_pubkey(Authctxt *authctxt) | |
a306f2dd | 700 | { |
188adeb2 | 701 | static int idx = 0; |
702 | int sent = 0; | |
fee56204 | 703 | Key *key; |
704 | char *filename; | |
188adeb2 | 705 | |
fa08c86b | 706 | if (authctxt->agent != NULL) { |
707 | do { | |
708 | sent = userauth_pubkey_agent(authctxt); | |
709 | } while(!sent && authctxt->agent->howmany > 0); | |
710 | } | |
711 | while (!sent && idx < options.num_identity_files) { | |
fee56204 | 712 | key = options.identity_keys[idx]; |
713 | filename = options.identity_files[idx]; | |
714 | if (key == NULL) { | |
715 | debug("try privkey: %s", filename); | |
716 | key = load_identity_file(filename); | |
717 | if (key != NULL) { | |
718 | sent = sign_and_send_pubkey(authctxt, key, | |
719 | key_sign_cb); | |
720 | key_free(key); | |
721 | } | |
722 | } else if (key->type != KEY_RSA1) { | |
723 | debug("try pubkey: %s", filename); | |
724 | sent = send_pubkey_test(authctxt, key, | |
725 | identity_sign_cb, idx); | |
726 | } | |
fa08c86b | 727 | idx++; |
728 | } | |
188adeb2 | 729 | return sent; |
730 | } | |
a306f2dd | 731 | |
94ec8c6b | 732 | /* |
733 | * Send userauth request message specifying keyboard-interactive method. | |
734 | */ | |
735 | int | |
736 | userauth_kbdint(Authctxt *authctxt) | |
737 | { | |
738 | static int attempt = 0; | |
739 | ||
740 | if (attempt++ >= options.number_of_password_prompts) | |
741 | return 0; | |
742 | ||
743 | debug2("userauth_kbdint"); | |
744 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
745 | packet_put_cstring(authctxt->server_user); | |
746 | packet_put_cstring(authctxt->service); | |
747 | packet_put_cstring(authctxt->method->name); | |
748 | packet_put_cstring(""); /* lang */ | |
749 | packet_put_cstring(options.kbd_interactive_devices ? | |
750 | options.kbd_interactive_devices : ""); | |
751 | packet_send(); | |
94ec8c6b | 752 | |
753 | dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req); | |
754 | return 1; | |
755 | } | |
756 | ||
757 | /* | |
f72e01a5 | 758 | * parse INFO_REQUEST, prompt user and send INFO_RESPONSE |
94ec8c6b | 759 | */ |
760 | void | |
761 | input_userauth_info_req(int type, int plen, void *ctxt) | |
762 | { | |
763 | Authctxt *authctxt = ctxt; | |
f72e01a5 | 764 | char *name, *inst, *lang, *prompt, *response; |
1e3b8b07 | 765 | u_int num_prompts, i; |
94ec8c6b | 766 | int echo = 0; |
767 | ||
768 | debug2("input_userauth_info_req"); | |
769 | ||
770 | if (authctxt == NULL) | |
771 | fatal("input_userauth_info_req: no authentication context"); | |
772 | ||
773 | name = packet_get_string(NULL); | |
774 | inst = packet_get_string(NULL); | |
775 | lang = packet_get_string(NULL); | |
94ec8c6b | 776 | if (strlen(name) > 0) |
80097c54 | 777 | log("%s", name); |
94ec8c6b | 778 | if (strlen(inst) > 0) |
80097c54 | 779 | log("%s", inst); |
f72e01a5 | 780 | xfree(name); |
94ec8c6b | 781 | xfree(inst); |
f72e01a5 | 782 | xfree(lang); |
94ec8c6b | 783 | |
784 | num_prompts = packet_get_int(); | |
785 | /* | |
786 | * Begin to build info response packet based on prompts requested. | |
787 | * We commit to providing the correct number of responses, so if | |
788 | * further on we run into a problem that prevents this, we have to | |
789 | * be sure and clean this up and send a correct error response. | |
790 | */ | |
791 | packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE); | |
792 | packet_put_int(num_prompts); | |
793 | ||
5ba55ada | 794 | debug2("input_userauth_info_req: num_prompts %d", num_prompts); |
94ec8c6b | 795 | for (i = 0; i < num_prompts; i++) { |
796 | prompt = packet_get_string(NULL); | |
797 | echo = packet_get_char(); | |
798 | ||
1843a425 | 799 | response = read_passphrase(prompt, echo ? RP_ECHO : 0); |
94ec8c6b | 800 | |
a6215e53 | 801 | packet_put_cstring(response); |
94ec8c6b | 802 | memset(response, 0, strlen(response)); |
803 | xfree(response); | |
804 | xfree(prompt); | |
805 | } | |
806 | packet_done(); /* done with parsing incoming message. */ | |
807 | ||
a6215e53 | 808 | packet_inject_ignore(64); |
94ec8c6b | 809 | packet_send(); |
94ec8c6b | 810 | } |
a306f2dd | 811 | |
8002af61 | 812 | /* |
813 | * this will be move to an external program (ssh-keysign) ASAP. ssh-keysign | |
814 | * will be setuid-root and the sbit can be removed from /usr/bin/ssh. | |
815 | */ | |
816 | int | |
817 | userauth_hostbased(Authctxt *authctxt) | |
818 | { | |
819 | Key *private = NULL; | |
820 | Buffer b; | |
821 | u_char *signature, *blob; | |
822 | char *chost, *pkalg, *p; | |
8dddf799 | 823 | const char *service; |
8002af61 | 824 | u_int blen, slen; |
f98c3421 | 825 | int ok, i, len, found = 0; |
8002af61 | 826 | |
827 | p = get_local_name(packet_get_connection_in()); | |
828 | if (p == NULL) { | |
829 | error("userauth_hostbased: cannot get local ipaddr/name"); | |
830 | return 0; | |
831 | } | |
f98c3421 | 832 | len = strlen(p) + 2; |
833 | chost = xmalloc(len); | |
834 | strlcpy(chost, p, len); | |
835 | strlcat(chost, ".", len); | |
8002af61 | 836 | debug2("userauth_hostbased: chost %s", chost); |
837 | /* check for a useful key */ | |
838 | for (i = 0; i < authctxt->nkeys; i++) { | |
839 | private = authctxt->keys[i]; | |
840 | if (private && private->type != KEY_RSA1) { | |
841 | found = 1; | |
842 | /* we take and free the key */ | |
843 | authctxt->keys[i] = NULL; | |
844 | break; | |
845 | } | |
846 | } | |
847 | if (!found) { | |
848 | xfree(chost); | |
849 | return 0; | |
850 | } | |
851 | if (key_to_blob(private, &blob, &blen) == 0) { | |
852 | key_free(private); | |
853 | xfree(chost); | |
854 | return 0; | |
855 | } | |
8dddf799 | 856 | service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" : |
857 | authctxt->service; | |
8002af61 | 858 | pkalg = xstrdup(key_ssh_name(private)); |
859 | buffer_init(&b); | |
8002af61 | 860 | /* construct data */ |
8dddf799 | 861 | buffer_put_string(&b, session_id2, session_id2_len); |
8002af61 | 862 | buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); |
863 | buffer_put_cstring(&b, authctxt->server_user); | |
8dddf799 | 864 | buffer_put_cstring(&b, service); |
8002af61 | 865 | buffer_put_cstring(&b, authctxt->method->name); |
866 | buffer_put_cstring(&b, pkalg); | |
867 | buffer_put_string(&b, blob, blen); | |
868 | buffer_put_cstring(&b, chost); | |
869 | buffer_put_cstring(&b, authctxt->local_user); | |
870 | #ifdef DEBUG_PK | |
871 | buffer_dump(&b); | |
872 | #endif | |
873 | debug2("xxx: chost %s", chost); | |
874 | ok = key_sign(private, &signature, &slen, buffer_ptr(&b), buffer_len(&b)); | |
875 | key_free(private); | |
876 | buffer_free(&b); | |
877 | if (ok != 0) { | |
878 | error("key_sign failed"); | |
879 | xfree(chost); | |
880 | xfree(pkalg); | |
881 | return 0; | |
882 | } | |
883 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
884 | packet_put_cstring(authctxt->server_user); | |
885 | packet_put_cstring(authctxt->service); | |
886 | packet_put_cstring(authctxt->method->name); | |
887 | packet_put_cstring(pkalg); | |
888 | packet_put_string(blob, blen); | |
889 | packet_put_cstring(chost); | |
890 | packet_put_cstring(authctxt->local_user); | |
891 | packet_put_string(signature, slen); | |
892 | memset(signature, 's', slen); | |
893 | xfree(signature); | |
894 | xfree(chost); | |
895 | xfree(pkalg); | |
896 | ||
897 | packet_send(); | |
898 | return 1; | |
899 | } | |
900 | ||
188adeb2 | 901 | /* find auth method */ |
902 | ||
188adeb2 | 903 | /* |
904 | * given auth method name, if configurable options permit this method fill | |
905 | * in auth_ident field and return true, otherwise return false. | |
906 | */ | |
396c147e | 907 | static int |
188adeb2 | 908 | authmethod_is_enabled(Authmethod *method) |
909 | { | |
910 | if (method == NULL) | |
911 | return 0; | |
912 | /* return false if options indicate this method is disabled */ | |
913 | if (method->enabled == NULL || *method->enabled == 0) | |
914 | return 0; | |
915 | /* return false if batch mode is enabled but method needs interactive mode */ | |
916 | if (method->batch_flag != NULL && *method->batch_flag != 0) | |
917 | return 0; | |
918 | return 1; | |
919 | } | |
a306f2dd | 920 | |
396c147e | 921 | static Authmethod * |
188adeb2 | 922 | authmethod_lookup(const char *name) |
923 | { | |
924 | Authmethod *method = NULL; | |
925 | if (name != NULL) | |
926 | for (method = authmethods; method->name != NULL; method++) | |
927 | if (strcmp(name, method->name) == 0) | |
928 | return method; | |
929 | debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); | |
930 | return NULL; | |
931 | } | |
932 | ||
cab80f75 | 933 | /* XXX internal state */ |
934 | static Authmethod *current = NULL; | |
935 | static char *supported = NULL; | |
936 | static char *preferred = NULL; | |
188adeb2 | 937 | /* |
938 | * Given the authentication method list sent by the server, return the | |
939 | * next method we should try. If the server initially sends a nil list, | |
cd332296 | 940 | * use a built-in default list. |
2b87da3b | 941 | */ |
396c147e | 942 | static Authmethod * |
188adeb2 | 943 | authmethod_get(char *authlist) |
944 | { | |
cab80f75 | 945 | |
946 | char *name = NULL; | |
947 | int next; | |
2b87da3b | 948 | |
188adeb2 | 949 | /* Use a suitable default if we're passed a nil list. */ |
950 | if (authlist == NULL || strlen(authlist) == 0) | |
cab80f75 | 951 | authlist = options.preferred_authentications; |
952 | ||
953 | if (supported == NULL || strcmp(authlist, supported) != 0) { | |
954 | debug3("start over, passed a different list %s", authlist); | |
955 | if (supported != NULL) | |
956 | xfree(supported); | |
957 | supported = xstrdup(authlist); | |
958 | preferred = options.preferred_authentications; | |
959 | debug3("preferred %s", preferred); | |
960 | current = NULL; | |
961 | } else if (current != NULL && authmethod_is_enabled(current)) | |
962 | return current; | |
188adeb2 | 963 | |
cab80f75 | 964 | for (;;) { |
965 | if ((name = match_list(preferred, supported, &next)) == NULL) { | |
966 | debug("no more auth methods to try"); | |
967 | current = NULL; | |
968 | return NULL; | |
969 | } | |
970 | preferred += next; | |
94ec8c6b | 971 | debug3("authmethod_lookup %s", name); |
cab80f75 | 972 | debug3("remaining preferred: %s", preferred); |
973 | if ((current = authmethod_lookup(name)) != NULL && | |
974 | authmethod_is_enabled(current)) { | |
94ec8c6b | 975 | debug3("authmethod_is_enabled %s", name); |
cab80f75 | 976 | debug("next auth method to try is %s", name); |
977 | return current; | |
94ec8c6b | 978 | } |
a306f2dd | 979 | } |
cab80f75 | 980 | } |
a22aff1f | 981 | |
a22aff1f | 982 | |
cab80f75 | 983 | #define DELIM "," |
ffb215be | 984 | |
985 | static char * | |
cab80f75 | 986 | authmethods_get(void) |
987 | { | |
988 | Authmethod *method = NULL; | |
989 | char buf[1024]; | |
990 | ||
991 | buf[0] = '\0'; | |
992 | for (method = authmethods; method->name != NULL; method++) { | |
993 | if (authmethod_is_enabled(method)) { | |
994 | if (buf[0] != '\0') | |
995 | strlcat(buf, DELIM, sizeof buf); | |
996 | strlcat(buf, method->name, sizeof buf); | |
997 | } | |
998 | } | |
999 | return xstrdup(buf); | |
a306f2dd | 1000 | } |