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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" |
d464095c | 26 | RCSID("$OpenBSD: auth2.c,v 1.34 2001/01/22 23:06:39 markus Exp $"); |
94ec8c6b | 27 | |
28 | #ifdef HAVE_OSF_SIA | |
29 | # include <sia.h> | |
30 | # include <siad.h> | |
31 | #endif | |
a306f2dd | 32 | |
a306f2dd | 33 | #include <openssl/evp.h> |
34 | ||
42f11eb2 | 35 | #include "ssh2.h" |
a306f2dd | 36 | #include "xmalloc.h" |
37 | #include "rsa.h" | |
a306f2dd | 38 | #include "pty.h" |
39 | #include "packet.h" | |
40 | #include "buffer.h" | |
42f11eb2 | 41 | #include "log.h" |
a306f2dd | 42 | #include "servconf.h" |
43 | #include "compat.h" | |
44 | #include "channels.h" | |
45 | #include "bufaux.h" | |
a306f2dd | 46 | #include "auth.h" |
47 | #include "session.h" | |
48 | #include "dispatch.h" | |
49 | #include "auth.h" | |
42f11eb2 | 50 | #include "cipher.h" |
a306f2dd | 51 | #include "key.h" |
52 | #include "kex.h" | |
42f11eb2 | 53 | #include "pathnames.h" |
a306f2dd | 54 | #include "uidswap.h" |
38c295d6 | 55 | #include "auth-options.h" |
a306f2dd | 56 | |
57 | /* import */ | |
58 | extern ServerOptions options; | |
1e3b8b07 | 59 | extern u_char *session_id2; |
a306f2dd | 60 | extern int session_id2_len; |
61 | ||
94ec8c6b | 62 | #ifdef WITH_AIXAUTHENTICATE |
63 | extern char *aixloginmsg; | |
64 | #endif | |
65 | #ifdef HAVE_OSF_SIA | |
66 | extern int saved_argc; | |
67 | extern char **saved_argv; | |
68 | #endif | |
69 | ||
70 | static Authctxt *x_authctxt = NULL; | |
71 | static int one = 1; | |
72 | ||
73 | typedef struct Authmethod Authmethod; | |
74 | struct Authmethod { | |
75 | char *name; | |
76 | int (*userauth)(Authctxt *authctxt); | |
77 | int *enabled; | |
78 | }; | |
79 | ||
a306f2dd | 80 | /* protocol */ |
81 | ||
188adeb2 | 82 | void input_service_request(int type, int plen, void *ctxt); |
83 | void input_userauth_request(int type, int plen, void *ctxt); | |
84 | void protocol_error(int type, int plen, void *ctxt); | |
a306f2dd | 85 | |
a306f2dd | 86 | /* helper */ |
94ec8c6b | 87 | Authmethod *authmethod_lookup(const char *name); |
88 | struct passwd *pwcopy(struct passwd *pw); | |
fa08c86b | 89 | int user_key_allowed(struct passwd *pw, Key *key); |
94ec8c6b | 90 | char *authmethods_get(void); |
a306f2dd | 91 | |
94ec8c6b | 92 | /* auth */ |
eea39c02 | 93 | void userauth_banner(void); |
94ec8c6b | 94 | int userauth_none(Authctxt *authctxt); |
95 | int userauth_passwd(Authctxt *authctxt); | |
96 | int userauth_pubkey(Authctxt *authctxt); | |
97 | int userauth_kbdint(Authctxt *authctxt); | |
98 | ||
99 | Authmethod authmethods[] = { | |
100 | {"none", | |
101 | userauth_none, | |
102 | &one}, | |
103 | {"publickey", | |
104 | userauth_pubkey, | |
fa08c86b | 105 | &options.pubkey_authentication}, |
94ec8c6b | 106 | {"keyboard-interactive", |
107 | userauth_kbdint, | |
108 | &options.kbd_interactive_authentication}, | |
109 | {"password", | |
110 | userauth_passwd, | |
111 | &options.password_authentication}, | |
112 | {NULL, NULL, NULL} | |
a306f2dd | 113 | }; |
a306f2dd | 114 | |
115 | /* | |
94ec8c6b | 116 | * loop until authctxt->success == TRUE |
a306f2dd | 117 | */ |
118 | ||
119 | void | |
120 | do_authentication2() | |
121 | { | |
59c97189 | 122 | Authctxt *authctxt = authctxt_new(); |
123 | ||
94ec8c6b | 124 | x_authctxt = authctxt; /*XXX*/ |
125 | ||
d464095c | 126 | /* challenge-reponse is implemented via keyboard interactive */ |
127 | if (options.challenge_reponse_authentication) | |
128 | options.kbd_interactive_authentication = 1; | |
129 | ||
59c97189 | 130 | #ifdef AFS |
131 | /* If machine has AFS, set process authentication group. */ | |
132 | if (k_hasafs()) { | |
133 | k_setpag(); | |
134 | k_unlog(); | |
135 | } | |
8cb940db | 136 | #endif |
a306f2dd | 137 | dispatch_init(&protocol_error); |
138 | dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request); | |
94ec8c6b | 139 | dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt); |
59c97189 | 140 | do_authenticated2(authctxt); |
a306f2dd | 141 | } |
142 | ||
143 | void | |
188adeb2 | 144 | protocol_error(int type, int plen, void *ctxt) |
a306f2dd | 145 | { |
146 | log("auth: protocol error: type %d plen %d", type, plen); | |
147 | packet_start(SSH2_MSG_UNIMPLEMENTED); | |
148 | packet_put_int(0); | |
149 | packet_send(); | |
150 | packet_write_wait(); | |
151 | } | |
152 | ||
153 | void | |
188adeb2 | 154 | input_service_request(int type, int plen, void *ctxt) |
a306f2dd | 155 | { |
94ec8c6b | 156 | Authctxt *authctxt = ctxt; |
1e3b8b07 | 157 | u_int len; |
a306f2dd | 158 | int accept = 0; |
159 | char *service = packet_get_string(&len); | |
160 | packet_done(); | |
161 | ||
94ec8c6b | 162 | if (authctxt == NULL) |
163 | fatal("input_service_request: no authctxt"); | |
164 | ||
a306f2dd | 165 | if (strcmp(service, "ssh-userauth") == 0) { |
94ec8c6b | 166 | if (!authctxt->success) { |
a306f2dd | 167 | accept = 1; |
168 | /* now we can handle user-auth requests */ | |
169 | dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request); | |
170 | } | |
171 | } | |
172 | /* XXX all other service requests are denied */ | |
173 | ||
174 | if (accept) { | |
175 | packet_start(SSH2_MSG_SERVICE_ACCEPT); | |
176 | packet_put_cstring(service); | |
177 | packet_send(); | |
178 | packet_write_wait(); | |
179 | } else { | |
180 | debug("bad service request %s", service); | |
181 | packet_disconnect("bad service request %s", service); | |
182 | } | |
183 | xfree(service); | |
184 | } | |
185 | ||
186 | void | |
188adeb2 | 187 | input_userauth_request(int type, int plen, void *ctxt) |
a306f2dd | 188 | { |
94ec8c6b | 189 | Authctxt *authctxt = ctxt; |
190 | Authmethod *m = NULL; | |
59c97189 | 191 | char *user, *service, *method, *style = NULL; |
a306f2dd | 192 | int authenticated = 0; |
a306f2dd | 193 | |
94ec8c6b | 194 | if (authctxt == NULL) |
195 | fatal("input_userauth_request: no authctxt"); | |
a306f2dd | 196 | |
94ec8c6b | 197 | user = packet_get_string(NULL); |
198 | service = packet_get_string(NULL); | |
199 | method = packet_get_string(NULL); | |
200 | debug("userauth-request for user %s service %s method %s", user, service, method); | |
8abcdba4 | 201 | debug("attempt %d failures %d", authctxt->attempt, authctxt->failures); |
94ec8c6b | 202 | |
59c97189 | 203 | if ((style = strchr(user, ':')) != NULL) |
204 | *style++ = 0; | |
205 | ||
8abcdba4 | 206 | if (authctxt->attempt++ == 0) { |
94ec8c6b | 207 | /* setup auth context */ |
208 | struct passwd *pw = NULL; | |
209 | setproctitle("%s", user); | |
210 | pw = getpwnam(user); | |
211 | if (pw && allowed_user(pw) && strcmp(service, "ssh-connection")==0) { | |
212 | authctxt->pw = pwcopy(pw); | |
213 | authctxt->valid = 1; | |
214 | debug2("input_userauth_request: setting up authctxt for %s", user); | |
215 | #ifdef USE_PAM | |
04fc7a67 | 216 | start_pam(pw->pw_name); |
94ec8c6b | 217 | #endif |
218 | } else { | |
219 | log("input_userauth_request: illegal user %s", user); | |
04fc7a67 | 220 | #ifdef USE_PAM |
221 | start_pam("NOUSER"); | |
222 | #endif | |
94ec8c6b | 223 | } |
224 | authctxt->user = xstrdup(user); | |
225 | authctxt->service = xstrdup(service); | |
59c97189 | 226 | authctxt->style = style ? xstrdup(style) : NULL; /* currently unused */ |
94ec8c6b | 227 | } else if (authctxt->valid) { |
228 | if (strcmp(user, authctxt->user) != 0 || | |
229 | strcmp(service, authctxt->service) != 0) { | |
230 | log("input_userauth_request: missmatch: (%s,%s)!=(%s,%s)", | |
231 | user, service, authctxt->user, authctxt->service); | |
232 | authctxt->valid = 0; | |
a306f2dd | 233 | } |
234 | } | |
59c97189 | 235 | /* reset state */ |
236 | dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE, &protocol_error); | |
237 | authctxt->postponed = 0; | |
9cd45ea4 | 238 | |
59c97189 | 239 | /* try to authenticate user */ |
94ec8c6b | 240 | m = authmethod_lookup(method); |
241 | if (m != NULL) { | |
242 | debug2("input_userauth_request: try method %s", method); | |
243 | authenticated = m->userauth(authctxt); | |
9cd45ea4 | 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 */ |
59c97189 | 250 | if (authenticated && authctxt->pw->pw_uid == 0 && !auth_root_allowed()) |
a306f2dd | 251 | authenticated = 0; |
a306f2dd | 252 | |
253 | #ifdef USE_PAM | |
606ea390 | 254 | if (authenticated && authctxt->user && !do_pam_account(authctxt->user, NULL)) |
9cd45ea4 | 255 | authenticated = 0; |
a306f2dd | 256 | #endif /* USE_PAM */ |
257 | ||
94ec8c6b | 258 | /* Log before sending the reply */ |
59c97189 | 259 | auth_log(authctxt, authenticated, method, " ssh2"); |
260 | ||
261 | if (!authctxt->postponed) | |
262 | userauth_reply(authctxt, authenticated); | |
94ec8c6b | 263 | |
264 | xfree(service); | |
265 | xfree(user); | |
266 | xfree(method); | |
267 | } | |
268 | ||
eea39c02 | 269 | void |
270 | userauth_banner(void) | |
271 | { | |
272 | struct stat st; | |
273 | char *banner = NULL; | |
274 | off_t len, n; | |
275 | int fd; | |
276 | ||
277 | if (options.banner == NULL || (datafellows & SSH_BUG_BANNER)) | |
278 | return; | |
279 | if ((fd = open(options.banner, O_RDONLY)) < 0) { | |
280 | error("userauth_banner: open %s failed: %s", | |
281 | options.banner, strerror(errno)); | |
282 | return; | |
283 | } | |
284 | if (fstat(fd, &st) < 0) | |
285 | goto done; | |
286 | len = st.st_size; | |
287 | banner = xmalloc(len + 1); | |
288 | if ((n = read(fd, banner, len)) < 0) | |
289 | goto done; | |
290 | banner[n] = '\0'; | |
291 | packet_start(SSH2_MSG_USERAUTH_BANNER); | |
292 | packet_put_cstring(banner); | |
293 | packet_put_cstring(""); /* language, unused */ | |
294 | packet_send(); | |
295 | debug("userauth_banner: sent"); | |
296 | done: | |
297 | if (banner) | |
298 | xfree(banner); | |
299 | close(fd); | |
300 | return; | |
301 | } | |
94ec8c6b | 302 | |
94ec8c6b | 303 | void |
304 | userauth_reply(Authctxt *authctxt, int authenticated) | |
305 | { | |
8abcdba4 | 306 | char *methods; |
59c97189 | 307 | |
1d1ffb87 | 308 | /* XXX todo: check if multiple auth methods are needed */ |
59c97189 | 309 | if (authenticated) { |
c1ef8333 | 310 | #ifdef WITH_AIXAUTHENTICATE |
311 | /* We don't have a pty yet, so just label the line as "ssh" */ | |
606ea390 | 312 | if (loginsuccess(authctxt->user?authctxt->user:"NOUSER", |
313 | get_canonical_hostname(), "ssh", &aixloginmsg) < 0) | |
c1ef8333 | 314 | aixloginmsg = NULL; |
315 | #endif /* WITH_AIXAUTHENTICATE */ | |
a306f2dd | 316 | /* turn off userauth */ |
317 | dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &protocol_error); | |
318 | packet_start(SSH2_MSG_USERAUTH_SUCCESS); | |
319 | packet_send(); | |
320 | packet_write_wait(); | |
321 | /* now we can break out */ | |
94ec8c6b | 322 | authctxt->success = 1; |
59c97189 | 323 | } else { |
324 | if (authctxt->failures++ > AUTH_FAIL_MAX) | |
325 | packet_disconnect(AUTH_FAIL_MSG, authctxt->user); | |
8abcdba4 | 326 | methods = authmethods_get(); |
a306f2dd | 327 | packet_start(SSH2_MSG_USERAUTH_FAILURE); |
94ec8c6b | 328 | packet_put_cstring(methods); |
329 | packet_put_char(0); /* XXX partial success, unused */ | |
a306f2dd | 330 | packet_send(); |
331 | packet_write_wait(); | |
94ec8c6b | 332 | xfree(methods); |
a306f2dd | 333 | } |
a306f2dd | 334 | } |
335 | ||
336 | int | |
94ec8c6b | 337 | userauth_none(Authctxt *authctxt) |
a306f2dd | 338 | { |
94ec8c6b | 339 | /* disable method "none", only allowed one time */ |
340 | Authmethod *m = authmethod_lookup("none"); | |
341 | if (m != NULL) | |
342 | m->enabled = NULL; | |
a306f2dd | 343 | packet_done(); |
eea39c02 | 344 | userauth_banner(); |
4d33e531 | 345 | |
94ec8c6b | 346 | if (authctxt->valid == 0) |
347 | return(0); | |
348 | ||
349 | #ifdef HAVE_CYGWIN | |
350 | if (check_nt_auth(1, authctxt->pw->pw_uid) == 0) | |
351 | return(0); | |
352 | #endif | |
a306f2dd | 353 | #ifdef USE_PAM |
94ec8c6b | 354 | return auth_pam_password(authctxt->pw, ""); |
4d33e531 | 355 | #elif defined(HAVE_OSF_SIA) |
94ec8c6b | 356 | return (sia_validate_user(NULL, saved_argc, saved_argv, |
606ea390 | 357 | get_canonical_hostname(), authctxt->user?authctxt->user:"NOUSER", |
358 | NULL, 0, NULL, "") == SIASUCCESS); | |
4d33e531 | 359 | #else /* !HAVE_OSF_SIA && !USE_PAM */ |
94ec8c6b | 360 | return auth_password(authctxt->pw, ""); |
a306f2dd | 361 | #endif /* USE_PAM */ |
362 | } | |
94ec8c6b | 363 | |
a306f2dd | 364 | int |
94ec8c6b | 365 | userauth_passwd(Authctxt *authctxt) |
a306f2dd | 366 | { |
367 | char *password; | |
368 | int authenticated = 0; | |
369 | int change; | |
1e3b8b07 | 370 | u_int len; |
a306f2dd | 371 | change = packet_get_char(); |
372 | if (change) | |
373 | log("password change not supported"); | |
374 | password = packet_get_string(&len); | |
375 | packet_done(); | |
94ec8c6b | 376 | if (authctxt->valid && |
377 | #ifdef HAVE_CYGWIN | |
378 | check_nt_auth(1, authctxt->pw->pw_uid) && | |
379 | #endif | |
a306f2dd | 380 | #ifdef USE_PAM |
94ec8c6b | 381 | auth_pam_password(authctxt->pw, password) == 1) |
4d33e531 | 382 | #elif defined(HAVE_OSF_SIA) |
383 | sia_validate_user(NULL, saved_argc, saved_argv, | |
606ea390 | 384 | get_canonical_hostname(), authctxt->user?authctxt->user:"NOUSER", |
385 | NULL, 0, NULL, password) == SIASUCCESS) | |
4d33e531 | 386 | #else /* !USE_PAM && !HAVE_OSF_SIA */ |
94ec8c6b | 387 | auth_password(authctxt->pw, password) == 1) |
a306f2dd | 388 | #endif /* USE_PAM */ |
389 | authenticated = 1; | |
390 | memset(password, 0, len); | |
391 | xfree(password); | |
392 | return authenticated; | |
393 | } | |
94ec8c6b | 394 | |
395 | int | |
396 | userauth_kbdint(Authctxt *authctxt) | |
397 | { | |
398 | int authenticated = 0; | |
399 | char *lang = NULL; | |
400 | char *devs = NULL; | |
401 | ||
402 | lang = packet_get_string(NULL); | |
403 | devs = packet_get_string(NULL); | |
404 | packet_done(); | |
405 | ||
406 | debug("keyboard-interactive language %s devs %s", lang, devs); | |
59c97189 | 407 | |
d464095c | 408 | if (options.challenge_reponse_authentication) |
409 | authenticated = auth2_challenge(authctxt, devs); | |
59c97189 | 410 | |
8c9fe09e | 411 | #ifdef USE_PAM |
412 | if (authenticated == 0) | |
413 | authenticated = auth2_pam(authctxt); | |
94ec8c6b | 414 | #endif |
415 | xfree(lang); | |
416 | xfree(devs); | |
417 | #ifdef HAVE_CYGWIN | |
418 | if (check_nt_auth(0, authctxt->pw->pw_uid) == 0) | |
419 | return(0); | |
420 | #endif | |
421 | return authenticated; | |
422 | } | |
423 | ||
a306f2dd | 424 | int |
94ec8c6b | 425 | userauth_pubkey(Authctxt *authctxt) |
a306f2dd | 426 | { |
427 | Buffer b; | |
428 | Key *key; | |
429 | char *pkalg, *pkblob, *sig; | |
1e3b8b07 | 430 | u_int alen, blen, slen; |
fa08c86b | 431 | int have_sig, pktype; |
a306f2dd | 432 | int authenticated = 0; |
433 | ||
94ec8c6b | 434 | if (!authctxt->valid) { |
435 | debug2("userauth_pubkey: disabled because of invalid user"); | |
a306f2dd | 436 | return 0; |
437 | } | |
438 | have_sig = packet_get_char(); | |
cbc5abf9 | 439 | if (datafellows & SSH_BUG_PKAUTH) { |
440 | debug2("userauth_pubkey: SSH_BUG_PKAUTH"); | |
441 | /* no explicit pkalg given */ | |
442 | pkblob = packet_get_string(&blen); | |
443 | buffer_init(&b); | |
444 | buffer_append(&b, pkblob, blen); | |
445 | /* so we have to extract the pkalg from the pkblob */ | |
446 | pkalg = buffer_get_string(&b, &alen); | |
447 | buffer_free(&b); | |
448 | } else { | |
449 | pkalg = packet_get_string(&alen); | |
450 | pkblob = packet_get_string(&blen); | |
451 | } | |
fa08c86b | 452 | pktype = key_type_from_name(pkalg); |
453 | if (pktype == KEY_UNSPEC) { | |
cbc5abf9 | 454 | /* this is perfectly legal */ |
455 | log("userauth_pubkey: unsupported public key algorithm: %s", pkalg); | |
94ec8c6b | 456 | xfree(pkalg); |
cbc5abf9 | 457 | xfree(pkblob); |
a306f2dd | 458 | return 0; |
459 | } | |
fa08c86b | 460 | key = key_from_blob(pkblob, blen); |
a306f2dd | 461 | if (key != NULL) { |
462 | if (have_sig) { | |
463 | sig = packet_get_string(&slen); | |
464 | packet_done(); | |
465 | buffer_init(&b); | |
33de75a3 | 466 | if (datafellows & SSH_OLD_SESSIONID) { |
74fc9186 | 467 | buffer_append(&b, session_id2, session_id2_len); |
33de75a3 | 468 | } else { |
469 | buffer_put_string(&b, session_id2, session_id2_len); | |
74fc9186 | 470 | } |
38c295d6 | 471 | /* reconstruct packet */ |
a306f2dd | 472 | buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); |
94ec8c6b | 473 | buffer_put_cstring(&b, authctxt->user); |
38c295d6 | 474 | buffer_put_cstring(&b, |
cbc5abf9 | 475 | datafellows & SSH_BUG_PKSERVICE ? |
38c295d6 | 476 | "ssh-userauth" : |
94ec8c6b | 477 | authctxt->service); |
cbc5abf9 | 478 | if (datafellows & SSH_BUG_PKAUTH) { |
479 | buffer_put_char(&b, have_sig); | |
480 | } else { | |
481 | buffer_put_cstring(&b, "publickey"); | |
482 | buffer_put_char(&b, have_sig); | |
483 | buffer_put_cstring(&b, key_ssh_name(key)); | |
484 | } | |
38c295d6 | 485 | buffer_put_string(&b, pkblob, blen); |
fa08c86b | 486 | #ifdef DEBUG_PK |
a306f2dd | 487 | buffer_dump(&b); |
488 | #endif | |
489 | /* test for correct signature */ | |
fa08c86b | 490 | if (user_key_allowed(authctxt->pw, key) && |
491 | key_verify(key, sig, slen, buffer_ptr(&b), buffer_len(&b)) == 1) | |
a306f2dd | 492 | authenticated = 1; |
493 | buffer_clear(&b); | |
494 | xfree(sig); | |
495 | } else { | |
94ec8c6b | 496 | debug("test whether pkalg/pkblob are acceptable"); |
a306f2dd | 497 | packet_done(); |
94ec8c6b | 498 | |
a306f2dd | 499 | /* XXX fake reply and always send PK_OK ? */ |
1d1ffb87 | 500 | /* |
501 | * XXX this allows testing whether a user is allowed | |
502 | * to login: if you happen to have a valid pubkey this | |
503 | * message is sent. the message is NEVER sent at all | |
504 | * if a user is not allowed to login. is this an | |
505 | * issue? -markus | |
506 | */ | |
fa08c86b | 507 | if (user_key_allowed(authctxt->pw, key)) { |
a306f2dd | 508 | packet_start(SSH2_MSG_USERAUTH_PK_OK); |
509 | packet_put_string(pkalg, alen); | |
510 | packet_put_string(pkblob, blen); | |
511 | packet_send(); | |
512 | packet_write_wait(); | |
513 | authenticated = -1; | |
514 | } | |
515 | } | |
94ec8c6b | 516 | if (authenticated != 1) |
517 | auth_clear_options(); | |
a306f2dd | 518 | key_free(key); |
519 | } | |
fa08c86b | 520 | debug2("userauth_pubkey: authenticated %d pkalg %s", authenticated, pkalg); |
a306f2dd | 521 | xfree(pkalg); |
522 | xfree(pkblob); | |
94ec8c6b | 523 | #ifdef HAVE_CYGWIN |
524 | if (check_nt_auth(0, authctxt->pw->pw_uid) == 0) | |
525 | return(0); | |
526 | #endif | |
a306f2dd | 527 | return authenticated; |
528 | } | |
529 | ||
94ec8c6b | 530 | /* get current user */ |
a306f2dd | 531 | |
532 | struct passwd* | |
533 | auth_get_user(void) | |
534 | { | |
94ec8c6b | 535 | return (x_authctxt != NULL && x_authctxt->valid) ? x_authctxt->pw : NULL; |
a306f2dd | 536 | } |
537 | ||
94ec8c6b | 538 | #define DELIM "," |
539 | ||
540 | char * | |
541 | authmethods_get(void) | |
a306f2dd | 542 | { |
94ec8c6b | 543 | Authmethod *method = NULL; |
1e3b8b07 | 544 | u_int size = 0; |
94ec8c6b | 545 | char *list; |
546 | ||
547 | for (method = authmethods; method->name != NULL; method++) { | |
548 | if (strcmp(method->name, "none") == 0) | |
549 | continue; | |
550 | if (method->enabled != NULL && *(method->enabled) != 0) { | |
551 | if (size != 0) | |
552 | size += strlen(DELIM); | |
553 | size += strlen(method->name); | |
a306f2dd | 554 | } |
94ec8c6b | 555 | } |
556 | size++; /* trailing '\0' */ | |
557 | list = xmalloc(size); | |
558 | list[0] = '\0'; | |
559 | ||
560 | for (method = authmethods; method->name != NULL; method++) { | |
561 | if (strcmp(method->name, "none") == 0) | |
562 | continue; | |
563 | if (method->enabled != NULL && *(method->enabled) != 0) { | |
564 | if (list[0] != '\0') | |
565 | strlcat(list, DELIM, size); | |
566 | strlcat(list, method->name, size); | |
a306f2dd | 567 | } |
568 | } | |
94ec8c6b | 569 | return list; |
570 | } | |
571 | ||
572 | Authmethod * | |
573 | authmethod_lookup(const char *name) | |
574 | { | |
575 | Authmethod *method = NULL; | |
576 | if (name != NULL) | |
577 | for (method = authmethods; method->name != NULL; method++) | |
578 | if (method->enabled != NULL && | |
579 | *(method->enabled) != 0 && | |
580 | strcmp(name, method->name) == 0) | |
581 | return method; | |
582 | debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); | |
583 | return NULL; | |
a306f2dd | 584 | } |
585 | ||
586 | /* return 1 if user allows given key */ | |
587 | int | |
fa08c86b | 588 | user_key_allowed(struct passwd *pw, Key *key) |
a306f2dd | 589 | { |
42f11eb2 | 590 | char line[8192], file[MAXPATHLEN]; |
a306f2dd | 591 | int found_key = 0; |
a306f2dd | 592 | FILE *f; |
1e3b8b07 | 593 | u_long linenum = 0; |
a306f2dd | 594 | struct stat st; |
595 | Key *found; | |
596 | ||
94ec8c6b | 597 | if (pw == NULL) |
598 | return 0; | |
599 | ||
a306f2dd | 600 | /* Temporarily use the user's uid. */ |
601 | temporarily_use_uid(pw->pw_uid); | |
602 | ||
603 | /* The authorized keys. */ | |
604 | snprintf(file, sizeof file, "%.500s/%.100s", pw->pw_dir, | |
42f11eb2 | 605 | _PATH_SSH_USER_PERMITTED_KEYS2); |
a306f2dd | 606 | |
607 | /* Fail quietly if file does not exist */ | |
608 | if (stat(file, &st) < 0) { | |
609 | /* Restore the privileged uid. */ | |
610 | restore_uid(); | |
611 | return 0; | |
612 | } | |
613 | /* Open the file containing the authorized keys. */ | |
614 | f = fopen(file, "r"); | |
615 | if (!f) { | |
616 | /* Restore the privileged uid. */ | |
617 | restore_uid(); | |
618 | return 0; | |
619 | } | |
620 | if (options.strict_modes) { | |
621 | int fail = 0; | |
622 | char buf[1024]; | |
623 | /* Check open file in order to avoid open/stat races */ | |
624 | if (fstat(fileno(f), &st) < 0 || | |
625 | (st.st_uid != 0 && st.st_uid != pw->pw_uid) || | |
626 | (st.st_mode & 022) != 0) { | |
de273eef | 627 | snprintf(buf, sizeof buf, |
628 | "%s authentication refused for %.100s: " | |
629 | "bad ownership or modes for '%s'.", | |
630 | key_type(key), pw->pw_name, file); | |
a306f2dd | 631 | fail = 1; |
632 | } else { | |
42f11eb2 | 633 | /* Check path to _PATH_SSH_USER_PERMITTED_KEYS */ |
a306f2dd | 634 | int i; |
635 | static const char *check[] = { | |
42f11eb2 | 636 | "", _PATH_SSH_USER_DIR, NULL |
a306f2dd | 637 | }; |
638 | for (i = 0; check[i]; i++) { | |
639 | snprintf(line, sizeof line, "%.500s/%.100s", | |
640 | pw->pw_dir, check[i]); | |
641 | if (stat(line, &st) < 0 || | |
642 | (st.st_uid != 0 && st.st_uid != pw->pw_uid) || | |
643 | (st.st_mode & 022) != 0) { | |
644 | snprintf(buf, sizeof buf, | |
de273eef | 645 | "%s authentication refused for %.100s: " |
a306f2dd | 646 | "bad ownership or modes for '%s'.", |
de273eef | 647 | key_type(key), pw->pw_name, line); |
a306f2dd | 648 | fail = 1; |
649 | break; | |
650 | } | |
651 | } | |
652 | } | |
653 | if (fail) { | |
a306f2dd | 654 | fclose(f); |
089fbbd2 | 655 | log("%s",buf); |
a306f2dd | 656 | restore_uid(); |
657 | return 0; | |
658 | } | |
659 | } | |
660 | found_key = 0; | |
de273eef | 661 | found = key_new(key->type); |
a306f2dd | 662 | |
663 | while (fgets(line, sizeof(line), f)) { | |
38c295d6 | 664 | char *cp, *options = NULL; |
a306f2dd | 665 | linenum++; |
666 | /* Skip leading whitespace, empty and comment lines. */ | |
667 | for (cp = line; *cp == ' ' || *cp == '\t'; cp++) | |
668 | ; | |
669 | if (!*cp || *cp == '\n' || *cp == '#') | |
670 | continue; | |
38c295d6 | 671 | |
fa08c86b | 672 | if (key_read(found, &cp) == -1) { |
38c295d6 | 673 | /* no key? check if there are options for this key */ |
674 | int quoted = 0; | |
fa08c86b | 675 | debug2("user_key_allowed: check options: '%s'", cp); |
38c295d6 | 676 | options = cp; |
677 | for (; *cp && (quoted || (*cp != ' ' && *cp != '\t')); cp++) { | |
678 | if (*cp == '\\' && cp[1] == '"') | |
679 | cp++; /* Skip both */ | |
680 | else if (*cp == '"') | |
681 | quoted = !quoted; | |
682 | } | |
683 | /* Skip remaining whitespace. */ | |
684 | for (; *cp == ' ' || *cp == '\t'; cp++) | |
685 | ; | |
fa08c86b | 686 | if (key_read(found, &cp) == -1) { |
687 | debug2("user_key_allowed: advance: '%s'", cp); | |
38c295d6 | 688 | /* still no key? advance to next line*/ |
689 | continue; | |
690 | } | |
691 | } | |
692 | if (key_equal(found, key) && | |
42f11eb2 | 693 | auth_parse_options(pw, options, file, linenum) == 1) { |
a306f2dd | 694 | found_key = 1; |
695 | debug("matching key found: file %s, line %ld", | |
696 | file, linenum); | |
697 | break; | |
698 | } | |
699 | } | |
700 | restore_uid(); | |
701 | fclose(f); | |
702 | key_free(found); | |
703 | return found_key; | |
704 | } |