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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 | */ | |
bcbf86ec | 24 | |
a306f2dd | 25 | #include "includes.h" |
d5bb9418 | 26 | RCSID("$OpenBSD: auth2.c,v 1.74 2001/12/05 03:56:39 itojun Exp $"); |
94ec8c6b | 27 | |
a306f2dd | 28 | #include <openssl/evp.h> |
29 | ||
42f11eb2 | 30 | #include "ssh2.h" |
a306f2dd | 31 | #include "xmalloc.h" |
32 | #include "rsa.h" | |
1729c161 | 33 | #include "sshpty.h" |
a306f2dd | 34 | #include "packet.h" |
35 | #include "buffer.h" | |
42f11eb2 | 36 | #include "log.h" |
a306f2dd | 37 | #include "servconf.h" |
38 | #include "compat.h" | |
a5efa1bb | 39 | #include "channels.h" |
a306f2dd | 40 | #include "bufaux.h" |
a306f2dd | 41 | #include "auth.h" |
42 | #include "session.h" | |
43 | #include "dispatch.h" | |
a306f2dd | 44 | #include "key.h" |
b0e305c9 | 45 | #include "cipher.h" |
a306f2dd | 46 | #include "kex.h" |
42f11eb2 | 47 | #include "pathnames.h" |
a306f2dd | 48 | #include "uidswap.h" |
38c295d6 | 49 | #include "auth-options.h" |
3b1a83df | 50 | #include "misc.h" |
8002af61 | 51 | #include "hostfile.h" |
52 | #include "canohost.h" | |
5ba55ada | 53 | #include "match.h" |
a306f2dd | 54 | |
55 | /* import */ | |
56 | extern ServerOptions options; | |
1e3b8b07 | 57 | extern u_char *session_id2; |
a306f2dd | 58 | extern int session_id2_len; |
59 | ||
94ec8c6b | 60 | static Authctxt *x_authctxt = NULL; |
61 | static int one = 1; | |
62 | ||
63 | typedef struct Authmethod Authmethod; | |
64 | struct Authmethod { | |
65 | char *name; | |
66 | int (*userauth)(Authctxt *authctxt); | |
67 | int *enabled; | |
68 | }; | |
69 | ||
a306f2dd | 70 | /* protocol */ |
71 | ||
396c147e | 72 | static void input_service_request(int, int, void *); |
73 | static void input_userauth_request(int, int, void *); | |
74 | static void protocol_error(int, int, void *); | |
a306f2dd | 75 | |
a306f2dd | 76 | /* helper */ |
396c147e | 77 | static Authmethod *authmethod_lookup(const char *); |
ffb215be | 78 | static char *authmethods_get(void); |
396c147e | 79 | static int user_key_allowed(struct passwd *, Key *); |
80 | static int hostbased_key_allowed(struct passwd *, const char *, char *, Key *); | |
a306f2dd | 81 | |
94ec8c6b | 82 | /* auth */ |
396c147e | 83 | static void userauth_banner(void); |
84 | static int userauth_none(Authctxt *); | |
85 | static int userauth_passwd(Authctxt *); | |
86 | static int userauth_pubkey(Authctxt *); | |
87 | static int userauth_hostbased(Authctxt *); | |
88 | static int userauth_kbdint(Authctxt *); | |
94ec8c6b | 89 | |
90 | Authmethod authmethods[] = { | |
91 | {"none", | |
92 | userauth_none, | |
93 | &one}, | |
94 | {"publickey", | |
95 | userauth_pubkey, | |
fa08c86b | 96 | &options.pubkey_authentication}, |
94ec8c6b | 97 | {"password", |
98 | userauth_passwd, | |
99 | &options.password_authentication}, | |
c845316f | 100 | {"keyboard-interactive", |
101 | userauth_kbdint, | |
102 | &options.kbd_interactive_authentication}, | |
8002af61 | 103 | {"hostbased", |
104 | userauth_hostbased, | |
105 | &options.hostbased_authentication}, | |
94ec8c6b | 106 | {NULL, NULL, NULL} |
a306f2dd | 107 | }; |
a306f2dd | 108 | |
109 | /* | |
94ec8c6b | 110 | * loop until authctxt->success == TRUE |
a306f2dd | 111 | */ |
112 | ||
113 | void | |
d5bb9418 | 114 | do_authentication2(void) |
a306f2dd | 115 | { |
59c97189 | 116 | Authctxt *authctxt = authctxt_new(); |
117 | ||
94ec8c6b | 118 | x_authctxt = authctxt; /*XXX*/ |
119 | ||
aa8003d6 | 120 | /* challenge-response is implemented via keyboard interactive */ |
5ba55ada | 121 | if (options.challenge_response_authentication) |
d464095c | 122 | options.kbd_interactive_authentication = 1; |
10f72868 | 123 | if (options.pam_authentication_via_kbd_int) |
124 | options.kbd_interactive_authentication = 1; | |
d464095c | 125 | |
a306f2dd | 126 | dispatch_init(&protocol_error); |
127 | dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request); | |
94ec8c6b | 128 | dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt); |
bb5639fe | 129 | do_authenticated(authctxt); |
a306f2dd | 130 | } |
131 | ||
396c147e | 132 | static void |
188adeb2 | 133 | protocol_error(int type, int plen, void *ctxt) |
a306f2dd | 134 | { |
135 | log("auth: protocol error: type %d plen %d", type, plen); | |
136 | packet_start(SSH2_MSG_UNIMPLEMENTED); | |
137 | packet_put_int(0); | |
138 | packet_send(); | |
139 | packet_write_wait(); | |
140 | } | |
141 | ||
396c147e | 142 | static void |
188adeb2 | 143 | input_service_request(int type, int plen, void *ctxt) |
a306f2dd | 144 | { |
94ec8c6b | 145 | Authctxt *authctxt = ctxt; |
1e3b8b07 | 146 | u_int len; |
a306f2dd | 147 | int accept = 0; |
148 | char *service = packet_get_string(&len); | |
149 | packet_done(); | |
150 | ||
94ec8c6b | 151 | if (authctxt == NULL) |
152 | fatal("input_service_request: no authctxt"); | |
153 | ||
a306f2dd | 154 | if (strcmp(service, "ssh-userauth") == 0) { |
94ec8c6b | 155 | if (!authctxt->success) { |
a306f2dd | 156 | accept = 1; |
157 | /* now we can handle user-auth requests */ | |
158 | dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request); | |
159 | } | |
160 | } | |
161 | /* XXX all other service requests are denied */ | |
162 | ||
163 | if (accept) { | |
164 | packet_start(SSH2_MSG_SERVICE_ACCEPT); | |
165 | packet_put_cstring(service); | |
166 | packet_send(); | |
167 | packet_write_wait(); | |
168 | } else { | |
169 | debug("bad service request %s", service); | |
170 | packet_disconnect("bad service request %s", service); | |
171 | } | |
172 | xfree(service); | |
173 | } | |
174 | ||
396c147e | 175 | static void |
188adeb2 | 176 | input_userauth_request(int type, int plen, void *ctxt) |
a306f2dd | 177 | { |
94ec8c6b | 178 | Authctxt *authctxt = ctxt; |
179 | Authmethod *m = NULL; | |
59c97189 | 180 | char *user, *service, *method, *style = NULL; |
a306f2dd | 181 | int authenticated = 0; |
a306f2dd | 182 | |
94ec8c6b | 183 | if (authctxt == NULL) |
184 | fatal("input_userauth_request: no authctxt"); | |
a306f2dd | 185 | |
94ec8c6b | 186 | user = packet_get_string(NULL); |
187 | service = packet_get_string(NULL); | |
188 | method = packet_get_string(NULL); | |
189 | debug("userauth-request for user %s service %s method %s", user, service, method); | |
8abcdba4 | 190 | debug("attempt %d failures %d", authctxt->attempt, authctxt->failures); |
94ec8c6b | 191 | |
59c97189 | 192 | if ((style = strchr(user, ':')) != NULL) |
193 | *style++ = 0; | |
194 | ||
2b87da3b | 195 | if (authctxt->attempt++ == 0) { |
94ec8c6b | 196 | /* setup auth context */ |
197 | struct passwd *pw = NULL; | |
94ec8c6b | 198 | pw = getpwnam(user); |
199 | if (pw && allowed_user(pw) && strcmp(service, "ssh-connection")==0) { | |
200 | authctxt->pw = pwcopy(pw); | |
201 | authctxt->valid = 1; | |
202 | debug2("input_userauth_request: setting up authctxt for %s", user); | |
203 | #ifdef USE_PAM | |
04fc7a67 | 204 | start_pam(pw->pw_name); |
94ec8c6b | 205 | #endif |
206 | } else { | |
207 | log("input_userauth_request: illegal user %s", user); | |
04fc7a67 | 208 | #ifdef USE_PAM |
209 | start_pam("NOUSER"); | |
210 | #endif | |
94ec8c6b | 211 | } |
6172e290 | 212 | setproctitle("%s", pw ? user : "unknown"); |
94ec8c6b | 213 | authctxt->user = xstrdup(user); |
214 | authctxt->service = xstrdup(service); | |
2a6a054e | 215 | authctxt->style = style ? xstrdup(style) : NULL; |
216 | } else if (strcmp(user, authctxt->user) != 0 || | |
217 | strcmp(service, authctxt->service) != 0) { | |
218 | packet_disconnect("Change of username or service not allowed: " | |
219 | "(%s,%s) -> (%s,%s)", | |
220 | authctxt->user, authctxt->service, user, service); | |
a306f2dd | 221 | } |
59c97189 | 222 | /* reset state */ |
223 | dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE, &protocol_error); | |
224 | authctxt->postponed = 0; | |
af774732 | 225 | #ifdef BSD_AUTH |
226 | if (authctxt->as) { | |
227 | auth_close(authctxt->as); | |
228 | authctxt->as = NULL; | |
229 | } | |
230 | #endif | |
9cd45ea4 | 231 | |
59c97189 | 232 | /* try to authenticate user */ |
94ec8c6b | 233 | m = authmethod_lookup(method); |
234 | if (m != NULL) { | |
235 | debug2("input_userauth_request: try method %s", method); | |
236 | authenticated = m->userauth(authctxt); | |
9cd45ea4 | 237 | } |
d9cd3575 | 238 | userauth_finish(authctxt, authenticated, method); |
239 | ||
240 | xfree(service); | |
241 | xfree(user); | |
242 | xfree(method); | |
243 | } | |
244 | ||
245 | void | |
246 | userauth_finish(Authctxt *authctxt, int authenticated, char *method) | |
247 | { | |
4e81159c | 248 | char *methods; |
249 | ||
59c97189 | 250 | if (!authctxt->valid && authenticated) |
251 | fatal("INTERNAL ERROR: authenticated invalid user %s", | |
252 | authctxt->user); | |
9cd45ea4 | 253 | |
94ec8c6b | 254 | /* Special handling for root */ |
15853e93 | 255 | if (authenticated && authctxt->pw->pw_uid == 0 && |
256 | !auth_root_allowed(method)) | |
a306f2dd | 257 | authenticated = 0; |
a306f2dd | 258 | |
259 | #ifdef USE_PAM | |
edef62bf | 260 | if (authenticated && authctxt->user && !do_pam_account(authctxt->user, |
261 | NULL)) | |
9cd45ea4 | 262 | authenticated = 0; |
a306f2dd | 263 | #endif /* USE_PAM */ |
264 | ||
94ec8c6b | 265 | /* Log before sending the reply */ |
59c97189 | 266 | auth_log(authctxt, authenticated, method, " ssh2"); |
267 | ||
4e81159c | 268 | if (authctxt->postponed) |
269 | return; | |
270 | ||
271 | /* XXX todo: check if multiple auth methods are needed */ | |
272 | if (authenticated == 1) { | |
273 | /* turn off userauth */ | |
274 | dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &protocol_error); | |
275 | packet_start(SSH2_MSG_USERAUTH_SUCCESS); | |
276 | packet_send(); | |
277 | packet_write_wait(); | |
278 | /* now we can break out */ | |
279 | authctxt->success = 1; | |
280 | } else { | |
19e810f6 | 281 | if (authctxt->failures++ > AUTH_FAIL_MAX) { |
282 | #ifdef WITH_AIXAUTHENTICATE | |
283 | loginfailed(authctxt->user, | |
284 | get_canonical_hostname(options.reverse_mapping_check), | |
285 | "ssh"); | |
286 | #endif /* WITH_AIXAUTHENTICATE */ | |
4e81159c | 287 | packet_disconnect(AUTH_FAIL_MSG, authctxt->user); |
19e810f6 | 288 | } |
4e81159c | 289 | methods = authmethods_get(); |
290 | packet_start(SSH2_MSG_USERAUTH_FAILURE); | |
291 | packet_put_cstring(methods); | |
292 | packet_put_char(0); /* XXX partial success, unused */ | |
293 | packet_send(); | |
294 | packet_write_wait(); | |
295 | xfree(methods); | |
296 | } | |
94ec8c6b | 297 | } |
298 | ||
396c147e | 299 | static void |
eea39c02 | 300 | userauth_banner(void) |
301 | { | |
302 | struct stat st; | |
303 | char *banner = NULL; | |
304 | off_t len, n; | |
305 | int fd; | |
306 | ||
307 | if (options.banner == NULL || (datafellows & SSH_BUG_BANNER)) | |
308 | return; | |
0715ec6c | 309 | if ((fd = open(options.banner, O_RDONLY)) < 0) |
eea39c02 | 310 | return; |
eea39c02 | 311 | if (fstat(fd, &st) < 0) |
312 | goto done; | |
313 | len = st.st_size; | |
314 | banner = xmalloc(len + 1); | |
315 | if ((n = read(fd, banner, len)) < 0) | |
316 | goto done; | |
317 | banner[n] = '\0'; | |
318 | packet_start(SSH2_MSG_USERAUTH_BANNER); | |
319 | packet_put_cstring(banner); | |
320 | packet_put_cstring(""); /* language, unused */ | |
321 | packet_send(); | |
322 | debug("userauth_banner: sent"); | |
323 | done: | |
324 | if (banner) | |
325 | xfree(banner); | |
326 | close(fd); | |
327 | return; | |
328 | } | |
94ec8c6b | 329 | |
396c147e | 330 | static int |
94ec8c6b | 331 | userauth_none(Authctxt *authctxt) |
a306f2dd | 332 | { |
94ec8c6b | 333 | /* disable method "none", only allowed one time */ |
334 | Authmethod *m = authmethod_lookup("none"); | |
335 | if (m != NULL) | |
336 | m->enabled = NULL; | |
a306f2dd | 337 | packet_done(); |
2b87da3b | 338 | userauth_banner(); |
4d33e531 | 339 | |
94ec8c6b | 340 | if (authctxt->valid == 0) |
341 | return(0); | |
2b87da3b | 342 | |
94ec8c6b | 343 | #ifdef HAVE_CYGWIN |
344 | if (check_nt_auth(1, authctxt->pw->pw_uid) == 0) | |
345 | return(0); | |
346 | #endif | |
a306f2dd | 347 | #ifdef USE_PAM |
94ec8c6b | 348 | return auth_pam_password(authctxt->pw, ""); |
4d33e531 | 349 | #elif defined(HAVE_OSF_SIA) |
b7ccb051 | 350 | return 0; |
4d33e531 | 351 | #else /* !HAVE_OSF_SIA && !USE_PAM */ |
af774732 | 352 | return auth_password(authctxt, ""); |
a306f2dd | 353 | #endif /* USE_PAM */ |
354 | } | |
94ec8c6b | 355 | |
396c147e | 356 | static int |
94ec8c6b | 357 | userauth_passwd(Authctxt *authctxt) |
a306f2dd | 358 | { |
359 | char *password; | |
360 | int authenticated = 0; | |
361 | int change; | |
1e3b8b07 | 362 | u_int len; |
a306f2dd | 363 | change = packet_get_char(); |
364 | if (change) | |
365 | log("password change not supported"); | |
366 | password = packet_get_string(&len); | |
367 | packet_done(); | |
94ec8c6b | 368 | if (authctxt->valid && |
369 | #ifdef HAVE_CYGWIN | |
370 | check_nt_auth(1, authctxt->pw->pw_uid) && | |
371 | #endif | |
a306f2dd | 372 | #ifdef USE_PAM |
94ec8c6b | 373 | auth_pam_password(authctxt->pw, password) == 1) |
4d33e531 | 374 | #elif defined(HAVE_OSF_SIA) |
b7ccb051 | 375 | auth_sia_password(authctxt->user, password) == 1) |
4d33e531 | 376 | #else /* !USE_PAM && !HAVE_OSF_SIA */ |
af774732 | 377 | auth_password(authctxt, password) == 1) |
a306f2dd | 378 | #endif /* USE_PAM */ |
379 | authenticated = 1; | |
380 | memset(password, 0, len); | |
381 | xfree(password); | |
382 | return authenticated; | |
383 | } | |
94ec8c6b | 384 | |
396c147e | 385 | static int |
94ec8c6b | 386 | userauth_kbdint(Authctxt *authctxt) |
387 | { | |
388 | int authenticated = 0; | |
5ba55ada | 389 | char *lang, *devs; |
94ec8c6b | 390 | |
391 | lang = packet_get_string(NULL); | |
392 | devs = packet_get_string(NULL); | |
393 | packet_done(); | |
394 | ||
5ba55ada | 395 | debug("keyboard-interactive devs %s", devs); |
59c97189 | 396 | |
5ba55ada | 397 | if (options.challenge_response_authentication) |
d464095c | 398 | authenticated = auth2_challenge(authctxt, devs); |
59c97189 | 399 | |
8c9fe09e | 400 | #ifdef USE_PAM |
10f72868 | 401 | if (authenticated == 0 && options.pam_authentication_via_kbd_int) |
8c9fe09e | 402 | authenticated = auth2_pam(authctxt); |
94ec8c6b | 403 | #endif |
94ec8c6b | 404 | xfree(devs); |
5ba55ada | 405 | xfree(lang); |
94ec8c6b | 406 | #ifdef HAVE_CYGWIN |
407 | if (check_nt_auth(0, authctxt->pw->pw_uid) == 0) | |
408 | return(0); | |
409 | #endif | |
410 | return authenticated; | |
411 | } | |
412 | ||
396c147e | 413 | static int |
94ec8c6b | 414 | userauth_pubkey(Authctxt *authctxt) |
a306f2dd | 415 | { |
416 | Buffer b; | |
417 | Key *key; | |
418 | char *pkalg, *pkblob, *sig; | |
1e3b8b07 | 419 | u_int alen, blen, slen; |
fa08c86b | 420 | int have_sig, pktype; |
a306f2dd | 421 | int authenticated = 0; |
422 | ||
94ec8c6b | 423 | if (!authctxt->valid) { |
424 | debug2("userauth_pubkey: disabled because of invalid user"); | |
a306f2dd | 425 | return 0; |
426 | } | |
427 | have_sig = packet_get_char(); | |
cbc5abf9 | 428 | if (datafellows & SSH_BUG_PKAUTH) { |
429 | debug2("userauth_pubkey: SSH_BUG_PKAUTH"); | |
430 | /* no explicit pkalg given */ | |
431 | pkblob = packet_get_string(&blen); | |
432 | buffer_init(&b); | |
433 | buffer_append(&b, pkblob, blen); | |
434 | /* so we have to extract the pkalg from the pkblob */ | |
435 | pkalg = buffer_get_string(&b, &alen); | |
436 | buffer_free(&b); | |
437 | } else { | |
438 | pkalg = packet_get_string(&alen); | |
439 | pkblob = packet_get_string(&blen); | |
440 | } | |
fa08c86b | 441 | pktype = key_type_from_name(pkalg); |
442 | if (pktype == KEY_UNSPEC) { | |
cbc5abf9 | 443 | /* this is perfectly legal */ |
444 | log("userauth_pubkey: unsupported public key algorithm: %s", pkalg); | |
94ec8c6b | 445 | xfree(pkalg); |
cbc5abf9 | 446 | xfree(pkblob); |
a306f2dd | 447 | return 0; |
448 | } | |
fa08c86b | 449 | key = key_from_blob(pkblob, blen); |
a306f2dd | 450 | if (key != NULL) { |
451 | if (have_sig) { | |
452 | sig = packet_get_string(&slen); | |
453 | packet_done(); | |
454 | buffer_init(&b); | |
33de75a3 | 455 | if (datafellows & SSH_OLD_SESSIONID) { |
74fc9186 | 456 | buffer_append(&b, session_id2, session_id2_len); |
33de75a3 | 457 | } else { |
458 | buffer_put_string(&b, session_id2, session_id2_len); | |
74fc9186 | 459 | } |
38c295d6 | 460 | /* reconstruct packet */ |
a306f2dd | 461 | buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); |
94ec8c6b | 462 | buffer_put_cstring(&b, authctxt->user); |
38c295d6 | 463 | buffer_put_cstring(&b, |
cbc5abf9 | 464 | datafellows & SSH_BUG_PKSERVICE ? |
38c295d6 | 465 | "ssh-userauth" : |
94ec8c6b | 466 | authctxt->service); |
cbc5abf9 | 467 | if (datafellows & SSH_BUG_PKAUTH) { |
468 | buffer_put_char(&b, have_sig); | |
469 | } else { | |
470 | buffer_put_cstring(&b, "publickey"); | |
471 | buffer_put_char(&b, have_sig); | |
5cf13595 | 472 | buffer_put_cstring(&b, pkalg); |
cbc5abf9 | 473 | } |
38c295d6 | 474 | buffer_put_string(&b, pkblob, blen); |
fa08c86b | 475 | #ifdef DEBUG_PK |
a306f2dd | 476 | buffer_dump(&b); |
477 | #endif | |
478 | /* test for correct signature */ | |
fa08c86b | 479 | if (user_key_allowed(authctxt->pw, key) && |
480 | key_verify(key, sig, slen, buffer_ptr(&b), buffer_len(&b)) == 1) | |
a306f2dd | 481 | authenticated = 1; |
482 | buffer_clear(&b); | |
483 | xfree(sig); | |
484 | } else { | |
94ec8c6b | 485 | debug("test whether pkalg/pkblob are acceptable"); |
a306f2dd | 486 | packet_done(); |
94ec8c6b | 487 | |
a306f2dd | 488 | /* XXX fake reply and always send PK_OK ? */ |
1d1ffb87 | 489 | /* |
490 | * XXX this allows testing whether a user is allowed | |
491 | * to login: if you happen to have a valid pubkey this | |
492 | * message is sent. the message is NEVER sent at all | |
493 | * if a user is not allowed to login. is this an | |
494 | * issue? -markus | |
495 | */ | |
fa08c86b | 496 | if (user_key_allowed(authctxt->pw, key)) { |
a306f2dd | 497 | packet_start(SSH2_MSG_USERAUTH_PK_OK); |
498 | packet_put_string(pkalg, alen); | |
499 | packet_put_string(pkblob, blen); | |
500 | packet_send(); | |
501 | packet_write_wait(); | |
25f4c264 | 502 | authctxt->postponed = 1; |
a306f2dd | 503 | } |
504 | } | |
94ec8c6b | 505 | if (authenticated != 1) |
506 | auth_clear_options(); | |
a306f2dd | 507 | key_free(key); |
508 | } | |
fa08c86b | 509 | debug2("userauth_pubkey: authenticated %d pkalg %s", authenticated, pkalg); |
a306f2dd | 510 | xfree(pkalg); |
511 | xfree(pkblob); | |
94ec8c6b | 512 | #ifdef HAVE_CYGWIN |
513 | if (check_nt_auth(0, authctxt->pw->pw_uid) == 0) | |
514 | return(0); | |
515 | #endif | |
a306f2dd | 516 | return authenticated; |
517 | } | |
518 | ||
396c147e | 519 | static int |
8002af61 | 520 | userauth_hostbased(Authctxt *authctxt) |
521 | { | |
522 | Buffer b; | |
523 | Key *key; | |
8dddf799 | 524 | char *pkalg, *pkblob, *sig, *cuser, *chost, *service; |
8002af61 | 525 | u_int alen, blen, slen; |
526 | int pktype; | |
527 | int authenticated = 0; | |
528 | ||
529 | if (!authctxt->valid) { | |
530 | debug2("userauth_hostbased: disabled because of invalid user"); | |
531 | return 0; | |
532 | } | |
533 | pkalg = packet_get_string(&alen); | |
534 | pkblob = packet_get_string(&blen); | |
535 | chost = packet_get_string(NULL); | |
536 | cuser = packet_get_string(NULL); | |
537 | sig = packet_get_string(&slen); | |
538 | ||
539 | debug("userauth_hostbased: cuser %s chost %s pkalg %s slen %d", | |
540 | cuser, chost, pkalg, slen); | |
541 | #ifdef DEBUG_PK | |
542 | debug("signature:"); | |
543 | buffer_init(&b); | |
544 | buffer_append(&b, sig, slen); | |
545 | buffer_dump(&b); | |
546 | buffer_free(&b); | |
547 | #endif | |
548 | pktype = key_type_from_name(pkalg); | |
549 | if (pktype == KEY_UNSPEC) { | |
550 | /* this is perfectly legal */ | |
551 | log("userauth_hostbased: unsupported " | |
552 | "public key algorithm: %s", pkalg); | |
553 | goto done; | |
554 | } | |
555 | key = key_from_blob(pkblob, blen); | |
556 | if (key == NULL) { | |
557 | debug("userauth_hostbased: cannot decode key: %s", pkalg); | |
558 | goto done; | |
559 | } | |
8dddf799 | 560 | service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" : |
561 | authctxt->service; | |
8002af61 | 562 | buffer_init(&b); |
8dddf799 | 563 | buffer_put_string(&b, session_id2, session_id2_len); |
8002af61 | 564 | /* reconstruct packet */ |
565 | buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); | |
566 | buffer_put_cstring(&b, authctxt->user); | |
8dddf799 | 567 | buffer_put_cstring(&b, service); |
8002af61 | 568 | buffer_put_cstring(&b, "hostbased"); |
569 | buffer_put_string(&b, pkalg, alen); | |
570 | buffer_put_string(&b, pkblob, blen); | |
571 | buffer_put_cstring(&b, chost); | |
572 | buffer_put_cstring(&b, cuser); | |
573 | #ifdef DEBUG_PK | |
574 | buffer_dump(&b); | |
575 | #endif | |
576 | /* test for allowed key and correct signature */ | |
577 | if (hostbased_key_allowed(authctxt->pw, cuser, chost, key) && | |
578 | key_verify(key, sig, slen, buffer_ptr(&b), buffer_len(&b)) == 1) | |
579 | authenticated = 1; | |
580 | ||
581 | buffer_clear(&b); | |
582 | key_free(key); | |
583 | ||
584 | done: | |
585 | debug2("userauth_hostbased: authenticated %d", authenticated); | |
586 | xfree(pkalg); | |
587 | xfree(pkblob); | |
588 | xfree(cuser); | |
589 | xfree(chost); | |
590 | xfree(sig); | |
591 | return authenticated; | |
592 | } | |
593 | ||
94ec8c6b | 594 | /* get current user */ |
a306f2dd | 595 | |
596 | struct passwd* | |
597 | auth_get_user(void) | |
598 | { | |
94ec8c6b | 599 | return (x_authctxt != NULL && x_authctxt->valid) ? x_authctxt->pw : NULL; |
a306f2dd | 600 | } |
601 | ||
94ec8c6b | 602 | #define DELIM "," |
603 | ||
ffb215be | 604 | static char * |
94ec8c6b | 605 | authmethods_get(void) |
a306f2dd | 606 | { |
94ec8c6b | 607 | Authmethod *method = NULL; |
1e3b8b07 | 608 | u_int size = 0; |
94ec8c6b | 609 | char *list; |
610 | ||
611 | for (method = authmethods; method->name != NULL; method++) { | |
612 | if (strcmp(method->name, "none") == 0) | |
613 | continue; | |
614 | if (method->enabled != NULL && *(method->enabled) != 0) { | |
615 | if (size != 0) | |
616 | size += strlen(DELIM); | |
617 | size += strlen(method->name); | |
a306f2dd | 618 | } |
94ec8c6b | 619 | } |
620 | size++; /* trailing '\0' */ | |
621 | list = xmalloc(size); | |
622 | list[0] = '\0'; | |
623 | ||
624 | for (method = authmethods; method->name != NULL; method++) { | |
625 | if (strcmp(method->name, "none") == 0) | |
626 | continue; | |
627 | if (method->enabled != NULL && *(method->enabled) != 0) { | |
628 | if (list[0] != '\0') | |
629 | strlcat(list, DELIM, size); | |
630 | strlcat(list, method->name, size); | |
a306f2dd | 631 | } |
632 | } | |
94ec8c6b | 633 | return list; |
634 | } | |
635 | ||
396c147e | 636 | static Authmethod * |
94ec8c6b | 637 | authmethod_lookup(const char *name) |
638 | { | |
639 | Authmethod *method = NULL; | |
640 | if (name != NULL) | |
641 | for (method = authmethods; method->name != NULL; method++) | |
642 | if (method->enabled != NULL && | |
643 | *(method->enabled) != 0 && | |
644 | strcmp(name, method->name) == 0) | |
645 | return method; | |
646 | debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); | |
647 | return NULL; | |
a306f2dd | 648 | } |
649 | ||
650 | /* return 1 if user allows given key */ | |
396c147e | 651 | static int |
96a7b0cc | 652 | user_key_allowed2(struct passwd *pw, Key *key, char *file) |
a306f2dd | 653 | { |
96a7b0cc | 654 | char line[8192]; |
a306f2dd | 655 | int found_key = 0; |
a306f2dd | 656 | FILE *f; |
1e3b8b07 | 657 | u_long linenum = 0; |
a306f2dd | 658 | struct stat st; |
659 | Key *found; | |
660 | ||
94ec8c6b | 661 | if (pw == NULL) |
662 | return 0; | |
663 | ||
a306f2dd | 664 | /* Temporarily use the user's uid. */ |
63bd8c36 | 665 | temporarily_use_uid(pw); |
a306f2dd | 666 | |
c8445989 | 667 | debug("trying public key file %s", file); |
a306f2dd | 668 | |
669 | /* Fail quietly if file does not exist */ | |
670 | if (stat(file, &st) < 0) { | |
671 | /* Restore the privileged uid. */ | |
672 | restore_uid(); | |
673 | return 0; | |
674 | } | |
675 | /* Open the file containing the authorized keys. */ | |
676 | f = fopen(file, "r"); | |
677 | if (!f) { | |
678 | /* Restore the privileged uid. */ | |
679 | restore_uid(); | |
680 | return 0; | |
681 | } | |
c8445989 | 682 | if (options.strict_modes && |
0c9664c2 | 683 | secure_filename(f, file, pw, line, sizeof(line)) != 0) { |
c8445989 | 684 | fclose(f); |
685 | log("Authentication refused: %s", line); | |
686 | restore_uid(); | |
687 | return 0; | |
a306f2dd | 688 | } |
c8445989 | 689 | |
a306f2dd | 690 | found_key = 0; |
de273eef | 691 | found = key_new(key->type); |
a306f2dd | 692 | |
693 | while (fgets(line, sizeof(line), f)) { | |
38c295d6 | 694 | char *cp, *options = NULL; |
a306f2dd | 695 | linenum++; |
696 | /* Skip leading whitespace, empty and comment lines. */ | |
697 | for (cp = line; *cp == ' ' || *cp == '\t'; cp++) | |
698 | ; | |
699 | if (!*cp || *cp == '\n' || *cp == '#') | |
700 | continue; | |
38c295d6 | 701 | |
ddcfed57 | 702 | if (key_read(found, &cp) != 1) { |
38c295d6 | 703 | /* no key? check if there are options for this key */ |
704 | int quoted = 0; | |
fa08c86b | 705 | debug2("user_key_allowed: check options: '%s'", cp); |
38c295d6 | 706 | options = cp; |
707 | for (; *cp && (quoted || (*cp != ' ' && *cp != '\t')); cp++) { | |
708 | if (*cp == '\\' && cp[1] == '"') | |
709 | cp++; /* Skip both */ | |
710 | else if (*cp == '"') | |
711 | quoted = !quoted; | |
712 | } | |
713 | /* Skip remaining whitespace. */ | |
714 | for (; *cp == ' ' || *cp == '\t'; cp++) | |
715 | ; | |
ddcfed57 | 716 | if (key_read(found, &cp) != 1) { |
fa08c86b | 717 | debug2("user_key_allowed: advance: '%s'", cp); |
38c295d6 | 718 | /* still no key? advance to next line*/ |
719 | continue; | |
720 | } | |
721 | } | |
722 | if (key_equal(found, key) && | |
42f11eb2 | 723 | auth_parse_options(pw, options, file, linenum) == 1) { |
a306f2dd | 724 | found_key = 1; |
1bdee08c | 725 | debug("matching key found: file %s, line %lu", |
a306f2dd | 726 | file, linenum); |
727 | break; | |
728 | } | |
729 | } | |
730 | restore_uid(); | |
731 | fclose(f); | |
732 | key_free(found); | |
539af7f5 | 733 | if (!found_key) |
734 | debug2("key not found"); | |
a306f2dd | 735 | return found_key; |
736 | } | |
8002af61 | 737 | |
96a7b0cc | 738 | /* check whether given key is in .ssh/authorized_keys* */ |
396c147e | 739 | static int |
96a7b0cc | 740 | user_key_allowed(struct passwd *pw, Key *key) |
741 | { | |
742 | int success; | |
743 | char *file; | |
744 | ||
745 | file = authorized_keys_file(pw); | |
746 | success = user_key_allowed2(pw, key, file); | |
747 | xfree(file); | |
748 | if (success) | |
749 | return success; | |
750 | ||
751 | /* try suffix "2" for backward compat, too */ | |
752 | file = authorized_keys_file2(pw); | |
753 | success = user_key_allowed2(pw, key, file); | |
754 | xfree(file); | |
755 | return success; | |
756 | } | |
757 | ||
8002af61 | 758 | /* return 1 if given hostkey is allowed */ |
396c147e | 759 | static int |
57a5edd8 | 760 | hostbased_key_allowed(struct passwd *pw, const char *cuser, char *chost, |
8002af61 | 761 | Key *key) |
762 | { | |
8002af61 | 763 | const char *resolvedname, *ipaddr, *lookup; |
17a3011c | 764 | HostStatus host_status; |
765 | int len; | |
8002af61 | 766 | |
767 | resolvedname = get_canonical_hostname(options.reverse_mapping_check); | |
768 | ipaddr = get_remote_ipaddr(); | |
769 | ||
f98c3421 | 770 | debug2("userauth_hostbased: chost %s resolvedname %s ipaddr %s", |
771 | chost, resolvedname, ipaddr); | |
8002af61 | 772 | |
773 | if (options.hostbased_uses_name_from_packet_only) { | |
774 | if (auth_rhosts2(pw, cuser, chost, chost) == 0) | |
775 | return 0; | |
776 | lookup = chost; | |
777 | } else { | |
f98c3421 | 778 | if (((len = strlen(chost)) > 0) && chost[len - 1] == '.') { |
779 | debug2("stripping trailing dot from chost %s", chost); | |
780 | chost[len - 1] = '\0'; | |
781 | } | |
8002af61 | 782 | if (strcasecmp(resolvedname, chost) != 0) |
783 | log("userauth_hostbased mismatch: " | |
784 | "client sends %s, but we resolve %s to %s", | |
785 | chost, ipaddr, resolvedname); | |
786 | if (auth_rhosts2(pw, cuser, resolvedname, ipaddr) == 0) | |
787 | return 0; | |
788 | lookup = resolvedname; | |
789 | } | |
790 | debug2("userauth_hostbased: access allowed by auth_rhosts2"); | |
791 | ||
d0c8ca5c | 792 | host_status = check_key_in_hostfiles(pw, key, lookup, |
793 | _PATH_SSH_SYSTEM_HOSTFILE, | |
73473230 | 794 | options.ignore_user_known_hosts ? NULL : _PATH_SSH_USER_HOSTFILE); |
d0c8ca5c | 795 | |
796 | /* backward compat if no key has been found. */ | |
797 | if (host_status == HOST_NEW) | |
798 | host_status = check_key_in_hostfiles(pw, key, lookup, | |
799 | _PATH_SSH_SYSTEM_HOSTFILE2, | |
73473230 | 800 | options.ignore_user_known_hosts ? NULL : |
801 | _PATH_SSH_USER_HOSTFILE2); | |
8002af61 | 802 | |
8002af61 | 803 | return (host_status == HOST_OK); |
804 | } | |
d0c8ca5c | 805 |