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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" |
d9cd3575 | 26 | RCSID("$OpenBSD: auth2.c,v 1.49 2001/03/28 22:43:31 markus 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" | |
39 | #include "channels.h" | |
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" |
a306f2dd | 51 | |
52 | /* import */ | |
53 | extern ServerOptions options; | |
1e3b8b07 | 54 | extern u_char *session_id2; |
a306f2dd | 55 | extern int session_id2_len; |
56 | ||
94ec8c6b | 57 | #ifdef WITH_AIXAUTHENTICATE |
58 | extern char *aixloginmsg; | |
59 | #endif | |
94ec8c6b | 60 | |
61 | static Authctxt *x_authctxt = NULL; | |
62 | static int one = 1; | |
63 | ||
64 | typedef struct Authmethod Authmethod; | |
65 | struct Authmethod { | |
66 | char *name; | |
67 | int (*userauth)(Authctxt *authctxt); | |
68 | int *enabled; | |
69 | }; | |
70 | ||
a306f2dd | 71 | /* protocol */ |
72 | ||
188adeb2 | 73 | void input_service_request(int type, int plen, void *ctxt); |
74 | void input_userauth_request(int type, int plen, void *ctxt); | |
75 | void protocol_error(int type, int plen, void *ctxt); | |
a306f2dd | 76 | |
a306f2dd | 77 | /* helper */ |
94ec8c6b | 78 | Authmethod *authmethod_lookup(const char *name); |
fa08c86b | 79 | int user_key_allowed(struct passwd *pw, Key *key); |
94ec8c6b | 80 | char *authmethods_get(void); |
a306f2dd | 81 | |
94ec8c6b | 82 | /* auth */ |
eea39c02 | 83 | void userauth_banner(void); |
d9cd3575 | 84 | void userauth_reply(Authctxt *authctxt, int authenticated); |
94ec8c6b | 85 | int userauth_none(Authctxt *authctxt); |
86 | int userauth_passwd(Authctxt *authctxt); | |
87 | int userauth_pubkey(Authctxt *authctxt); | |
88 | int userauth_kbdint(Authctxt *authctxt); | |
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}, | |
94ec8c6b | 103 | {NULL, NULL, NULL} |
a306f2dd | 104 | }; |
a306f2dd | 105 | |
106 | /* | |
94ec8c6b | 107 | * loop until authctxt->success == TRUE |
a306f2dd | 108 | */ |
109 | ||
110 | void | |
111 | do_authentication2() | |
112 | { | |
59c97189 | 113 | Authctxt *authctxt = authctxt_new(); |
114 | ||
94ec8c6b | 115 | x_authctxt = authctxt; /*XXX*/ |
116 | ||
d464095c | 117 | /* challenge-reponse is implemented via keyboard interactive */ |
118 | if (options.challenge_reponse_authentication) | |
119 | options.kbd_interactive_authentication = 1; | |
120 | ||
a306f2dd | 121 | dispatch_init(&protocol_error); |
122 | dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request); | |
94ec8c6b | 123 | dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt); |
bb5639fe | 124 | do_authenticated(authctxt); |
a306f2dd | 125 | } |
126 | ||
127 | void | |
188adeb2 | 128 | protocol_error(int type, int plen, void *ctxt) |
a306f2dd | 129 | { |
130 | log("auth: protocol error: type %d plen %d", type, plen); | |
131 | packet_start(SSH2_MSG_UNIMPLEMENTED); | |
132 | packet_put_int(0); | |
133 | packet_send(); | |
134 | packet_write_wait(); | |
135 | } | |
136 | ||
137 | void | |
188adeb2 | 138 | input_service_request(int type, int plen, void *ctxt) |
a306f2dd | 139 | { |
94ec8c6b | 140 | Authctxt *authctxt = ctxt; |
1e3b8b07 | 141 | u_int len; |
a306f2dd | 142 | int accept = 0; |
143 | char *service = packet_get_string(&len); | |
144 | packet_done(); | |
145 | ||
94ec8c6b | 146 | if (authctxt == NULL) |
147 | fatal("input_service_request: no authctxt"); | |
148 | ||
a306f2dd | 149 | if (strcmp(service, "ssh-userauth") == 0) { |
94ec8c6b | 150 | if (!authctxt->success) { |
a306f2dd | 151 | accept = 1; |
152 | /* now we can handle user-auth requests */ | |
153 | dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request); | |
154 | } | |
155 | } | |
156 | /* XXX all other service requests are denied */ | |
157 | ||
158 | if (accept) { | |
159 | packet_start(SSH2_MSG_SERVICE_ACCEPT); | |
160 | packet_put_cstring(service); | |
161 | packet_send(); | |
162 | packet_write_wait(); | |
163 | } else { | |
164 | debug("bad service request %s", service); | |
165 | packet_disconnect("bad service request %s", service); | |
166 | } | |
167 | xfree(service); | |
168 | } | |
169 | ||
170 | void | |
188adeb2 | 171 | input_userauth_request(int type, int plen, void *ctxt) |
a306f2dd | 172 | { |
94ec8c6b | 173 | Authctxt *authctxt = ctxt; |
174 | Authmethod *m = NULL; | |
59c97189 | 175 | char *user, *service, *method, *style = NULL; |
a306f2dd | 176 | int authenticated = 0; |
a306f2dd | 177 | |
94ec8c6b | 178 | if (authctxt == NULL) |
179 | fatal("input_userauth_request: no authctxt"); | |
a306f2dd | 180 | |
94ec8c6b | 181 | user = packet_get_string(NULL); |
182 | service = packet_get_string(NULL); | |
183 | method = packet_get_string(NULL); | |
184 | debug("userauth-request for user %s service %s method %s", user, service, method); | |
8abcdba4 | 185 | debug("attempt %d failures %d", authctxt->attempt, authctxt->failures); |
94ec8c6b | 186 | |
59c97189 | 187 | if ((style = strchr(user, ':')) != NULL) |
188 | *style++ = 0; | |
189 | ||
2b87da3b | 190 | if (authctxt->attempt++ == 0) { |
94ec8c6b | 191 | /* setup auth context */ |
192 | struct passwd *pw = NULL; | |
94ec8c6b | 193 | pw = getpwnam(user); |
194 | if (pw && allowed_user(pw) && strcmp(service, "ssh-connection")==0) { | |
195 | authctxt->pw = pwcopy(pw); | |
196 | authctxt->valid = 1; | |
197 | debug2("input_userauth_request: setting up authctxt for %s", user); | |
198 | #ifdef USE_PAM | |
04fc7a67 | 199 | start_pam(pw->pw_name); |
94ec8c6b | 200 | #endif |
201 | } else { | |
202 | log("input_userauth_request: illegal user %s", user); | |
04fc7a67 | 203 | #ifdef USE_PAM |
204 | start_pam("NOUSER"); | |
205 | #endif | |
94ec8c6b | 206 | } |
6172e290 | 207 | setproctitle("%s", pw ? user : "unknown"); |
94ec8c6b | 208 | authctxt->user = xstrdup(user); |
209 | authctxt->service = xstrdup(service); | |
59c97189 | 210 | authctxt->style = style ? xstrdup(style) : NULL; /* currently unused */ |
94ec8c6b | 211 | } else if (authctxt->valid) { |
212 | if (strcmp(user, authctxt->user) != 0 || | |
213 | strcmp(service, authctxt->service) != 0) { | |
214 | log("input_userauth_request: missmatch: (%s,%s)!=(%s,%s)", | |
215 | user, service, authctxt->user, authctxt->service); | |
216 | authctxt->valid = 0; | |
a306f2dd | 217 | } |
218 | } | |
59c97189 | 219 | /* reset state */ |
220 | dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE, &protocol_error); | |
221 | authctxt->postponed = 0; | |
af774732 | 222 | #ifdef BSD_AUTH |
223 | if (authctxt->as) { | |
224 | auth_close(authctxt->as); | |
225 | authctxt->as = NULL; | |
226 | } | |
227 | #endif | |
9cd45ea4 | 228 | |
59c97189 | 229 | /* try to authenticate user */ |
94ec8c6b | 230 | m = authmethod_lookup(method); |
231 | if (m != NULL) { | |
232 | debug2("input_userauth_request: try method %s", method); | |
233 | authenticated = m->userauth(authctxt); | |
9cd45ea4 | 234 | } |
d9cd3575 | 235 | userauth_finish(authctxt, authenticated, method); |
236 | ||
237 | xfree(service); | |
238 | xfree(user); | |
239 | xfree(method); | |
240 | } | |
241 | ||
242 | void | |
243 | userauth_finish(Authctxt *authctxt, int authenticated, char *method) | |
244 | { | |
59c97189 | 245 | if (!authctxt->valid && authenticated) |
246 | fatal("INTERNAL ERROR: authenticated invalid user %s", | |
247 | authctxt->user); | |
9cd45ea4 | 248 | |
94ec8c6b | 249 | /* Special handling for root */ |
15853e93 | 250 | if (authenticated && authctxt->pw->pw_uid == 0 && |
251 | !auth_root_allowed(method)) | |
a306f2dd | 252 | authenticated = 0; |
a306f2dd | 253 | |
254 | #ifdef USE_PAM | |
edef62bf | 255 | if (authenticated && authctxt->user && !do_pam_account(authctxt->user, |
256 | NULL)) | |
9cd45ea4 | 257 | authenticated = 0; |
a306f2dd | 258 | #endif /* USE_PAM */ |
259 | ||
94ec8c6b | 260 | /* Log before sending the reply */ |
59c97189 | 261 | auth_log(authctxt, authenticated, method, " ssh2"); |
262 | ||
263 | if (!authctxt->postponed) | |
264 | userauth_reply(authctxt, authenticated); | |
94ec8c6b | 265 | } |
266 | ||
eea39c02 | 267 | void |
268 | userauth_banner(void) | |
269 | { | |
270 | struct stat st; | |
271 | char *banner = NULL; | |
272 | off_t len, n; | |
273 | int fd; | |
274 | ||
275 | if (options.banner == NULL || (datafellows & SSH_BUG_BANNER)) | |
276 | return; | |
277 | if ((fd = open(options.banner, O_RDONLY)) < 0) { | |
278 | error("userauth_banner: open %s failed: %s", | |
279 | options.banner, strerror(errno)); | |
280 | return; | |
281 | } | |
282 | if (fstat(fd, &st) < 0) | |
283 | goto done; | |
284 | len = st.st_size; | |
285 | banner = xmalloc(len + 1); | |
286 | if ((n = read(fd, banner, len)) < 0) | |
287 | goto done; | |
288 | banner[n] = '\0'; | |
289 | packet_start(SSH2_MSG_USERAUTH_BANNER); | |
290 | packet_put_cstring(banner); | |
291 | packet_put_cstring(""); /* language, unused */ | |
292 | packet_send(); | |
293 | debug("userauth_banner: sent"); | |
294 | done: | |
295 | if (banner) | |
296 | xfree(banner); | |
297 | close(fd); | |
298 | return; | |
299 | } | |
94ec8c6b | 300 | |
2b87da3b | 301 | void |
94ec8c6b | 302 | userauth_reply(Authctxt *authctxt, int authenticated) |
303 | { | |
8abcdba4 | 304 | char *methods; |
59c97189 | 305 | |
1d1ffb87 | 306 | /* XXX todo: check if multiple auth methods are needed */ |
25f4c264 | 307 | if (authenticated == 1) { |
c1ef8333 | 308 | #ifdef WITH_AIXAUTHENTICATE |
309 | /* We don't have a pty yet, so just label the line as "ssh" */ | |
2b87da3b | 310 | if (loginsuccess(authctxt->user?authctxt->user:"NOUSER", |
311 | get_canonical_hostname(options.reverse_mapping_check), | |
61e96248 | 312 | "ssh", &aixloginmsg) < 0) |
c1ef8333 | 313 | aixloginmsg = NULL; |
314 | #endif /* WITH_AIXAUTHENTICATE */ | |
a306f2dd | 315 | /* turn off userauth */ |
316 | dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &protocol_error); | |
317 | packet_start(SSH2_MSG_USERAUTH_SUCCESS); | |
318 | packet_send(); | |
319 | packet_write_wait(); | |
320 | /* now we can break out */ | |
94ec8c6b | 321 | authctxt->success = 1; |
59c97189 | 322 | } else { |
323 | if (authctxt->failures++ > AUTH_FAIL_MAX) | |
2b87da3b | 324 | packet_disconnect(AUTH_FAIL_MSG, authctxt->user); |
8abcdba4 | 325 | methods = authmethods_get(); |
a306f2dd | 326 | packet_start(SSH2_MSG_USERAUTH_FAILURE); |
94ec8c6b | 327 | packet_put_cstring(methods); |
328 | packet_put_char(0); /* XXX partial success, unused */ | |
a306f2dd | 329 | packet_send(); |
330 | packet_write_wait(); | |
94ec8c6b | 331 | xfree(methods); |
a306f2dd | 332 | } |
a306f2dd | 333 | } |
334 | ||
335 | int | |
94ec8c6b | 336 | userauth_none(Authctxt *authctxt) |
a306f2dd | 337 | { |
94ec8c6b | 338 | /* disable method "none", only allowed one time */ |
339 | Authmethod *m = authmethod_lookup("none"); | |
340 | if (m != NULL) | |
341 | m->enabled = NULL; | |
a306f2dd | 342 | packet_done(); |
2b87da3b | 343 | userauth_banner(); |
4d33e531 | 344 | |
94ec8c6b | 345 | if (authctxt->valid == 0) |
346 | return(0); | |
2b87da3b | 347 | |
94ec8c6b | 348 | #ifdef HAVE_CYGWIN |
349 | if (check_nt_auth(1, authctxt->pw->pw_uid) == 0) | |
350 | return(0); | |
351 | #endif | |
a306f2dd | 352 | #ifdef USE_PAM |
94ec8c6b | 353 | return auth_pam_password(authctxt->pw, ""); |
4d33e531 | 354 | #elif defined(HAVE_OSF_SIA) |
b7ccb051 | 355 | return 0; |
4d33e531 | 356 | #else /* !HAVE_OSF_SIA && !USE_PAM */ |
af774732 | 357 | return auth_password(authctxt, ""); |
a306f2dd | 358 | #endif /* USE_PAM */ |
359 | } | |
94ec8c6b | 360 | |
a306f2dd | 361 | int |
94ec8c6b | 362 | userauth_passwd(Authctxt *authctxt) |
a306f2dd | 363 | { |
364 | char *password; | |
365 | int authenticated = 0; | |
366 | int change; | |
1e3b8b07 | 367 | u_int len; |
a306f2dd | 368 | change = packet_get_char(); |
369 | if (change) | |
370 | log("password change not supported"); | |
371 | password = packet_get_string(&len); | |
372 | packet_done(); | |
94ec8c6b | 373 | if (authctxt->valid && |
374 | #ifdef HAVE_CYGWIN | |
375 | check_nt_auth(1, authctxt->pw->pw_uid) && | |
376 | #endif | |
a306f2dd | 377 | #ifdef USE_PAM |
94ec8c6b | 378 | auth_pam_password(authctxt->pw, password) == 1) |
4d33e531 | 379 | #elif defined(HAVE_OSF_SIA) |
b7ccb051 | 380 | auth_sia_password(authctxt->user, password) == 1) |
4d33e531 | 381 | #else /* !USE_PAM && !HAVE_OSF_SIA */ |
af774732 | 382 | auth_password(authctxt, password) == 1) |
a306f2dd | 383 | #endif /* USE_PAM */ |
384 | authenticated = 1; | |
385 | memset(password, 0, len); | |
386 | xfree(password); | |
387 | return authenticated; | |
388 | } | |
94ec8c6b | 389 | |
390 | int | |
391 | userauth_kbdint(Authctxt *authctxt) | |
392 | { | |
393 | int authenticated = 0; | |
394 | char *lang = NULL; | |
395 | char *devs = NULL; | |
396 | ||
397 | lang = packet_get_string(NULL); | |
398 | devs = packet_get_string(NULL); | |
399 | packet_done(); | |
400 | ||
401 | debug("keyboard-interactive language %s devs %s", lang, devs); | |
59c97189 | 402 | |
d464095c | 403 | if (options.challenge_reponse_authentication) |
404 | authenticated = auth2_challenge(authctxt, devs); | |
59c97189 | 405 | |
8c9fe09e | 406 | #ifdef USE_PAM |
407 | if (authenticated == 0) | |
408 | authenticated = auth2_pam(authctxt); | |
94ec8c6b | 409 | #endif |
410 | xfree(lang); | |
411 | xfree(devs); | |
412 | #ifdef HAVE_CYGWIN | |
413 | if (check_nt_auth(0, authctxt->pw->pw_uid) == 0) | |
414 | return(0); | |
415 | #endif | |
416 | return authenticated; | |
417 | } | |
418 | ||
a306f2dd | 419 | int |
94ec8c6b | 420 | userauth_pubkey(Authctxt *authctxt) |
a306f2dd | 421 | { |
422 | Buffer b; | |
423 | Key *key; | |
424 | char *pkalg, *pkblob, *sig; | |
1e3b8b07 | 425 | u_int alen, blen, slen; |
fa08c86b | 426 | int have_sig, pktype; |
a306f2dd | 427 | int authenticated = 0; |
428 | ||
94ec8c6b | 429 | if (!authctxt->valid) { |
430 | debug2("userauth_pubkey: disabled because of invalid user"); | |
a306f2dd | 431 | return 0; |
432 | } | |
433 | have_sig = packet_get_char(); | |
cbc5abf9 | 434 | if (datafellows & SSH_BUG_PKAUTH) { |
435 | debug2("userauth_pubkey: SSH_BUG_PKAUTH"); | |
436 | /* no explicit pkalg given */ | |
437 | pkblob = packet_get_string(&blen); | |
438 | buffer_init(&b); | |
439 | buffer_append(&b, pkblob, blen); | |
440 | /* so we have to extract the pkalg from the pkblob */ | |
441 | pkalg = buffer_get_string(&b, &alen); | |
442 | buffer_free(&b); | |
443 | } else { | |
444 | pkalg = packet_get_string(&alen); | |
445 | pkblob = packet_get_string(&blen); | |
446 | } | |
fa08c86b | 447 | pktype = key_type_from_name(pkalg); |
448 | if (pktype == KEY_UNSPEC) { | |
cbc5abf9 | 449 | /* this is perfectly legal */ |
450 | log("userauth_pubkey: unsupported public key algorithm: %s", pkalg); | |
94ec8c6b | 451 | xfree(pkalg); |
cbc5abf9 | 452 | xfree(pkblob); |
a306f2dd | 453 | return 0; |
454 | } | |
fa08c86b | 455 | key = key_from_blob(pkblob, blen); |
a306f2dd | 456 | if (key != NULL) { |
457 | if (have_sig) { | |
458 | sig = packet_get_string(&slen); | |
459 | packet_done(); | |
460 | buffer_init(&b); | |
33de75a3 | 461 | if (datafellows & SSH_OLD_SESSIONID) { |
74fc9186 | 462 | buffer_append(&b, session_id2, session_id2_len); |
33de75a3 | 463 | } else { |
464 | buffer_put_string(&b, session_id2, session_id2_len); | |
74fc9186 | 465 | } |
38c295d6 | 466 | /* reconstruct packet */ |
a306f2dd | 467 | buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); |
94ec8c6b | 468 | buffer_put_cstring(&b, authctxt->user); |
38c295d6 | 469 | buffer_put_cstring(&b, |
cbc5abf9 | 470 | datafellows & SSH_BUG_PKSERVICE ? |
38c295d6 | 471 | "ssh-userauth" : |
94ec8c6b | 472 | authctxt->service); |
cbc5abf9 | 473 | if (datafellows & SSH_BUG_PKAUTH) { |
474 | buffer_put_char(&b, have_sig); | |
475 | } else { | |
476 | buffer_put_cstring(&b, "publickey"); | |
477 | buffer_put_char(&b, have_sig); | |
478 | buffer_put_cstring(&b, key_ssh_name(key)); | |
479 | } | |
38c295d6 | 480 | buffer_put_string(&b, pkblob, blen); |
fa08c86b | 481 | #ifdef DEBUG_PK |
a306f2dd | 482 | buffer_dump(&b); |
483 | #endif | |
484 | /* test for correct signature */ | |
fa08c86b | 485 | if (user_key_allowed(authctxt->pw, key) && |
486 | key_verify(key, sig, slen, buffer_ptr(&b), buffer_len(&b)) == 1) | |
a306f2dd | 487 | authenticated = 1; |
488 | buffer_clear(&b); | |
489 | xfree(sig); | |
490 | } else { | |
94ec8c6b | 491 | debug("test whether pkalg/pkblob are acceptable"); |
a306f2dd | 492 | packet_done(); |
94ec8c6b | 493 | |
a306f2dd | 494 | /* XXX fake reply and always send PK_OK ? */ |
1d1ffb87 | 495 | /* |
496 | * XXX this allows testing whether a user is allowed | |
497 | * to login: if you happen to have a valid pubkey this | |
498 | * message is sent. the message is NEVER sent at all | |
499 | * if a user is not allowed to login. is this an | |
500 | * issue? -markus | |
501 | */ | |
fa08c86b | 502 | if (user_key_allowed(authctxt->pw, key)) { |
a306f2dd | 503 | packet_start(SSH2_MSG_USERAUTH_PK_OK); |
504 | packet_put_string(pkalg, alen); | |
505 | packet_put_string(pkblob, blen); | |
506 | packet_send(); | |
507 | packet_write_wait(); | |
25f4c264 | 508 | authctxt->postponed = 1; |
a306f2dd | 509 | } |
510 | } | |
94ec8c6b | 511 | if (authenticated != 1) |
512 | auth_clear_options(); | |
a306f2dd | 513 | key_free(key); |
514 | } | |
fa08c86b | 515 | debug2("userauth_pubkey: authenticated %d pkalg %s", authenticated, pkalg); |
a306f2dd | 516 | xfree(pkalg); |
517 | xfree(pkblob); | |
94ec8c6b | 518 | #ifdef HAVE_CYGWIN |
519 | if (check_nt_auth(0, authctxt->pw->pw_uid) == 0) | |
520 | return(0); | |
521 | #endif | |
a306f2dd | 522 | return authenticated; |
523 | } | |
524 | ||
94ec8c6b | 525 | /* get current user */ |
a306f2dd | 526 | |
527 | struct passwd* | |
528 | auth_get_user(void) | |
529 | { | |
94ec8c6b | 530 | return (x_authctxt != NULL && x_authctxt->valid) ? x_authctxt->pw : NULL; |
a306f2dd | 531 | } |
532 | ||
94ec8c6b | 533 | #define DELIM "," |
534 | ||
535 | char * | |
536 | authmethods_get(void) | |
a306f2dd | 537 | { |
94ec8c6b | 538 | Authmethod *method = NULL; |
1e3b8b07 | 539 | u_int size = 0; |
94ec8c6b | 540 | char *list; |
541 | ||
542 | for (method = authmethods; method->name != NULL; method++) { | |
543 | if (strcmp(method->name, "none") == 0) | |
544 | continue; | |
545 | if (method->enabled != NULL && *(method->enabled) != 0) { | |
546 | if (size != 0) | |
547 | size += strlen(DELIM); | |
548 | size += strlen(method->name); | |
a306f2dd | 549 | } |
94ec8c6b | 550 | } |
551 | size++; /* trailing '\0' */ | |
552 | list = xmalloc(size); | |
553 | list[0] = '\0'; | |
554 | ||
555 | for (method = authmethods; method->name != NULL; method++) { | |
556 | if (strcmp(method->name, "none") == 0) | |
557 | continue; | |
558 | if (method->enabled != NULL && *(method->enabled) != 0) { | |
559 | if (list[0] != '\0') | |
560 | strlcat(list, DELIM, size); | |
561 | strlcat(list, method->name, size); | |
a306f2dd | 562 | } |
563 | } | |
94ec8c6b | 564 | return list; |
565 | } | |
566 | ||
567 | Authmethod * | |
568 | authmethod_lookup(const char *name) | |
569 | { | |
570 | Authmethod *method = NULL; | |
571 | if (name != NULL) | |
572 | for (method = authmethods; method->name != NULL; method++) | |
573 | if (method->enabled != NULL && | |
574 | *(method->enabled) != 0 && | |
575 | strcmp(name, method->name) == 0) | |
576 | return method; | |
577 | debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); | |
578 | return NULL; | |
a306f2dd | 579 | } |
580 | ||
581 | /* return 1 if user allows given key */ | |
582 | int | |
fa08c86b | 583 | user_key_allowed(struct passwd *pw, Key *key) |
a306f2dd | 584 | { |
42f11eb2 | 585 | char line[8192], file[MAXPATHLEN]; |
a306f2dd | 586 | int found_key = 0; |
a306f2dd | 587 | FILE *f; |
1e3b8b07 | 588 | u_long linenum = 0; |
a306f2dd | 589 | struct stat st; |
590 | Key *found; | |
591 | ||
94ec8c6b | 592 | if (pw == NULL) |
593 | return 0; | |
594 | ||
a306f2dd | 595 | /* Temporarily use the user's uid. */ |
596 | temporarily_use_uid(pw->pw_uid); | |
597 | ||
598 | /* The authorized keys. */ | |
599 | snprintf(file, sizeof file, "%.500s/%.100s", pw->pw_dir, | |
42f11eb2 | 600 | _PATH_SSH_USER_PERMITTED_KEYS2); |
a306f2dd | 601 | |
602 | /* Fail quietly if file does not exist */ | |
603 | if (stat(file, &st) < 0) { | |
604 | /* Restore the privileged uid. */ | |
605 | restore_uid(); | |
606 | return 0; | |
607 | } | |
608 | /* Open the file containing the authorized keys. */ | |
609 | f = fopen(file, "r"); | |
610 | if (!f) { | |
611 | /* Restore the privileged uid. */ | |
612 | restore_uid(); | |
613 | return 0; | |
614 | } | |
615 | if (options.strict_modes) { | |
616 | int fail = 0; | |
617 | char buf[1024]; | |
618 | /* Check open file in order to avoid open/stat races */ | |
619 | if (fstat(fileno(f), &st) < 0 || | |
620 | (st.st_uid != 0 && st.st_uid != pw->pw_uid) || | |
621 | (st.st_mode & 022) != 0) { | |
de273eef | 622 | snprintf(buf, sizeof buf, |
623 | "%s authentication refused for %.100s: " | |
624 | "bad ownership or modes for '%s'.", | |
625 | key_type(key), pw->pw_name, file); | |
a306f2dd | 626 | fail = 1; |
627 | } else { | |
42f11eb2 | 628 | /* Check path to _PATH_SSH_USER_PERMITTED_KEYS */ |
a306f2dd | 629 | int i; |
630 | static const char *check[] = { | |
42f11eb2 | 631 | "", _PATH_SSH_USER_DIR, NULL |
a306f2dd | 632 | }; |
633 | for (i = 0; check[i]; i++) { | |
634 | snprintf(line, sizeof line, "%.500s/%.100s", | |
635 | pw->pw_dir, check[i]); | |
636 | if (stat(line, &st) < 0 || | |
637 | (st.st_uid != 0 && st.st_uid != pw->pw_uid) || | |
638 | (st.st_mode & 022) != 0) { | |
639 | snprintf(buf, sizeof buf, | |
de273eef | 640 | "%s authentication refused for %.100s: " |
a306f2dd | 641 | "bad ownership or modes for '%s'.", |
de273eef | 642 | key_type(key), pw->pw_name, line); |
a306f2dd | 643 | fail = 1; |
644 | break; | |
645 | } | |
646 | } | |
647 | } | |
648 | if (fail) { | |
a306f2dd | 649 | fclose(f); |
12bf85ed | 650 | log("%s", buf); |
a306f2dd | 651 | restore_uid(); |
652 | return 0; | |
653 | } | |
654 | } | |
655 | found_key = 0; | |
de273eef | 656 | found = key_new(key->type); |
a306f2dd | 657 | |
658 | while (fgets(line, sizeof(line), f)) { | |
38c295d6 | 659 | char *cp, *options = NULL; |
a306f2dd | 660 | linenum++; |
661 | /* Skip leading whitespace, empty and comment lines. */ | |
662 | for (cp = line; *cp == ' ' || *cp == '\t'; cp++) | |
663 | ; | |
664 | if (!*cp || *cp == '\n' || *cp == '#') | |
665 | continue; | |
38c295d6 | 666 | |
fa08c86b | 667 | if (key_read(found, &cp) == -1) { |
38c295d6 | 668 | /* no key? check if there are options for this key */ |
669 | int quoted = 0; | |
fa08c86b | 670 | debug2("user_key_allowed: check options: '%s'", cp); |
38c295d6 | 671 | options = cp; |
672 | for (; *cp && (quoted || (*cp != ' ' && *cp != '\t')); cp++) { | |
673 | if (*cp == '\\' && cp[1] == '"') | |
674 | cp++; /* Skip both */ | |
675 | else if (*cp == '"') | |
676 | quoted = !quoted; | |
677 | } | |
678 | /* Skip remaining whitespace. */ | |
679 | for (; *cp == ' ' || *cp == '\t'; cp++) | |
680 | ; | |
fa08c86b | 681 | if (key_read(found, &cp) == -1) { |
682 | debug2("user_key_allowed: advance: '%s'", cp); | |
38c295d6 | 683 | /* still no key? advance to next line*/ |
684 | continue; | |
685 | } | |
686 | } | |
687 | if (key_equal(found, key) && | |
42f11eb2 | 688 | auth_parse_options(pw, options, file, linenum) == 1) { |
a306f2dd | 689 | found_key = 1; |
690 | debug("matching key found: file %s, line %ld", | |
691 | file, linenum); | |
692 | break; | |
693 | } | |
694 | } | |
695 | restore_uid(); | |
696 | fclose(f); | |
697 | key_free(found); | |
539af7f5 | 698 | if (!found_key) |
699 | debug2("key not found"); | |
a306f2dd | 700 | return found_key; |
701 | } |