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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" |
53a24016 | 26 | RCSID("$OpenBSD: auth2.c,v 1.33 2001/01/22 08:32:53 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 | ||
59c97189 | 126 | #ifdef AFS |
127 | /* If machine has AFS, set process authentication group. */ | |
128 | if (k_hasafs()) { | |
129 | k_setpag(); | |
130 | k_unlog(); | |
131 | } | |
8cb940db | 132 | #endif |
a306f2dd | 133 | dispatch_init(&protocol_error); |
134 | dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request); | |
94ec8c6b | 135 | dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt); |
59c97189 | 136 | do_authenticated2(authctxt); |
a306f2dd | 137 | } |
138 | ||
139 | void | |
188adeb2 | 140 | protocol_error(int type, int plen, void *ctxt) |
a306f2dd | 141 | { |
142 | log("auth: protocol error: type %d plen %d", type, plen); | |
143 | packet_start(SSH2_MSG_UNIMPLEMENTED); | |
144 | packet_put_int(0); | |
145 | packet_send(); | |
146 | packet_write_wait(); | |
147 | } | |
148 | ||
149 | void | |
188adeb2 | 150 | input_service_request(int type, int plen, void *ctxt) |
a306f2dd | 151 | { |
94ec8c6b | 152 | Authctxt *authctxt = ctxt; |
1e3b8b07 | 153 | u_int len; |
a306f2dd | 154 | int accept = 0; |
155 | char *service = packet_get_string(&len); | |
156 | packet_done(); | |
157 | ||
94ec8c6b | 158 | if (authctxt == NULL) |
159 | fatal("input_service_request: no authctxt"); | |
160 | ||
a306f2dd | 161 | if (strcmp(service, "ssh-userauth") == 0) { |
94ec8c6b | 162 | if (!authctxt->success) { |
a306f2dd | 163 | accept = 1; |
164 | /* now we can handle user-auth requests */ | |
165 | dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request); | |
166 | } | |
167 | } | |
168 | /* XXX all other service requests are denied */ | |
169 | ||
170 | if (accept) { | |
171 | packet_start(SSH2_MSG_SERVICE_ACCEPT); | |
172 | packet_put_cstring(service); | |
173 | packet_send(); | |
174 | packet_write_wait(); | |
175 | } else { | |
176 | debug("bad service request %s", service); | |
177 | packet_disconnect("bad service request %s", service); | |
178 | } | |
179 | xfree(service); | |
180 | } | |
181 | ||
182 | void | |
188adeb2 | 183 | input_userauth_request(int type, int plen, void *ctxt) |
a306f2dd | 184 | { |
94ec8c6b | 185 | Authctxt *authctxt = ctxt; |
186 | Authmethod *m = NULL; | |
59c97189 | 187 | char *user, *service, *method, *style = NULL; |
a306f2dd | 188 | int authenticated = 0; |
a306f2dd | 189 | |
94ec8c6b | 190 | if (authctxt == NULL) |
191 | fatal("input_userauth_request: no authctxt"); | |
a306f2dd | 192 | |
94ec8c6b | 193 | user = packet_get_string(NULL); |
194 | service = packet_get_string(NULL); | |
195 | method = packet_get_string(NULL); | |
196 | debug("userauth-request for user %s service %s method %s", user, service, method); | |
8abcdba4 | 197 | debug("attempt %d failures %d", authctxt->attempt, authctxt->failures); |
94ec8c6b | 198 | |
59c97189 | 199 | if ((style = strchr(user, ':')) != NULL) |
200 | *style++ = 0; | |
201 | ||
8abcdba4 | 202 | if (authctxt->attempt++ == 0) { |
94ec8c6b | 203 | /* setup auth context */ |
204 | struct passwd *pw = NULL; | |
205 | setproctitle("%s", user); | |
206 | pw = getpwnam(user); | |
207 | if (pw && allowed_user(pw) && strcmp(service, "ssh-connection")==0) { | |
208 | authctxt->pw = pwcopy(pw); | |
209 | authctxt->valid = 1; | |
210 | debug2("input_userauth_request: setting up authctxt for %s", user); | |
211 | #ifdef USE_PAM | |
04fc7a67 | 212 | start_pam(pw->pw_name); |
94ec8c6b | 213 | #endif |
214 | } else { | |
215 | log("input_userauth_request: illegal user %s", user); | |
04fc7a67 | 216 | #ifdef USE_PAM |
217 | start_pam("NOUSER"); | |
218 | #endif | |
94ec8c6b | 219 | } |
220 | authctxt->user = xstrdup(user); | |
221 | authctxt->service = xstrdup(service); | |
59c97189 | 222 | authctxt->style = style ? xstrdup(style) : NULL; /* currently unused */ |
94ec8c6b | 223 | } else if (authctxt->valid) { |
224 | if (strcmp(user, authctxt->user) != 0 || | |
225 | strcmp(service, authctxt->service) != 0) { | |
226 | log("input_userauth_request: missmatch: (%s,%s)!=(%s,%s)", | |
227 | user, service, authctxt->user, authctxt->service); | |
228 | authctxt->valid = 0; | |
a306f2dd | 229 | } |
230 | } | |
59c97189 | 231 | /* reset state */ |
232 | dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE, &protocol_error); | |
233 | authctxt->postponed = 0; | |
9cd45ea4 | 234 | |
59c97189 | 235 | /* try to authenticate user */ |
94ec8c6b | 236 | m = authmethod_lookup(method); |
237 | if (m != NULL) { | |
238 | debug2("input_userauth_request: try method %s", method); | |
239 | authenticated = m->userauth(authctxt); | |
9cd45ea4 | 240 | } |
59c97189 | 241 | if (!authctxt->valid && authenticated) |
242 | fatal("INTERNAL ERROR: authenticated invalid user %s", | |
243 | authctxt->user); | |
9cd45ea4 | 244 | |
94ec8c6b | 245 | /* Special handling for root */ |
59c97189 | 246 | if (authenticated && authctxt->pw->pw_uid == 0 && !auth_root_allowed()) |
a306f2dd | 247 | authenticated = 0; |
a306f2dd | 248 | |
249 | #ifdef USE_PAM | |
606ea390 | 250 | if (authenticated && authctxt->user && !do_pam_account(authctxt->user, NULL)) |
9cd45ea4 | 251 | authenticated = 0; |
a306f2dd | 252 | #endif /* USE_PAM */ |
253 | ||
94ec8c6b | 254 | /* Log before sending the reply */ |
59c97189 | 255 | auth_log(authctxt, authenticated, method, " ssh2"); |
256 | ||
257 | if (!authctxt->postponed) | |
258 | userauth_reply(authctxt, authenticated); | |
94ec8c6b | 259 | |
260 | xfree(service); | |
261 | xfree(user); | |
262 | xfree(method); | |
263 | } | |
264 | ||
eea39c02 | 265 | void |
266 | userauth_banner(void) | |
267 | { | |
268 | struct stat st; | |
269 | char *banner = NULL; | |
270 | off_t len, n; | |
271 | int fd; | |
272 | ||
273 | if (options.banner == NULL || (datafellows & SSH_BUG_BANNER)) | |
274 | return; | |
275 | if ((fd = open(options.banner, O_RDONLY)) < 0) { | |
276 | error("userauth_banner: open %s failed: %s", | |
277 | options.banner, strerror(errno)); | |
278 | return; | |
279 | } | |
280 | if (fstat(fd, &st) < 0) | |
281 | goto done; | |
282 | len = st.st_size; | |
283 | banner = xmalloc(len + 1); | |
284 | if ((n = read(fd, banner, len)) < 0) | |
285 | goto done; | |
286 | banner[n] = '\0'; | |
287 | packet_start(SSH2_MSG_USERAUTH_BANNER); | |
288 | packet_put_cstring(banner); | |
289 | packet_put_cstring(""); /* language, unused */ | |
290 | packet_send(); | |
291 | debug("userauth_banner: sent"); | |
292 | done: | |
293 | if (banner) | |
294 | xfree(banner); | |
295 | close(fd); | |
296 | return; | |
297 | } | |
94ec8c6b | 298 | |
94ec8c6b | 299 | void |
300 | userauth_reply(Authctxt *authctxt, int authenticated) | |
301 | { | |
8abcdba4 | 302 | char *methods; |
59c97189 | 303 | |
1d1ffb87 | 304 | /* XXX todo: check if multiple auth methods are needed */ |
59c97189 | 305 | if (authenticated) { |
c1ef8333 | 306 | #ifdef WITH_AIXAUTHENTICATE |
307 | /* We don't have a pty yet, so just label the line as "ssh" */ | |
606ea390 | 308 | if (loginsuccess(authctxt->user?authctxt->user:"NOUSER", |
309 | get_canonical_hostname(), "ssh", &aixloginmsg) < 0) | |
c1ef8333 | 310 | aixloginmsg = NULL; |
311 | #endif /* WITH_AIXAUTHENTICATE */ | |
a306f2dd | 312 | /* turn off userauth */ |
313 | dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &protocol_error); | |
314 | packet_start(SSH2_MSG_USERAUTH_SUCCESS); | |
315 | packet_send(); | |
316 | packet_write_wait(); | |
317 | /* now we can break out */ | |
94ec8c6b | 318 | authctxt->success = 1; |
59c97189 | 319 | } else { |
320 | if (authctxt->failures++ > AUTH_FAIL_MAX) | |
321 | packet_disconnect(AUTH_FAIL_MSG, authctxt->user); | |
8abcdba4 | 322 | methods = authmethods_get(); |
a306f2dd | 323 | packet_start(SSH2_MSG_USERAUTH_FAILURE); |
94ec8c6b | 324 | packet_put_cstring(methods); |
325 | packet_put_char(0); /* XXX partial success, unused */ | |
a306f2dd | 326 | packet_send(); |
327 | packet_write_wait(); | |
94ec8c6b | 328 | xfree(methods); |
a306f2dd | 329 | } |
a306f2dd | 330 | } |
331 | ||
332 | int | |
94ec8c6b | 333 | userauth_none(Authctxt *authctxt) |
a306f2dd | 334 | { |
94ec8c6b | 335 | /* disable method "none", only allowed one time */ |
336 | Authmethod *m = authmethod_lookup("none"); | |
337 | if (m != NULL) | |
338 | m->enabled = NULL; | |
a306f2dd | 339 | packet_done(); |
eea39c02 | 340 | userauth_banner(); |
4d33e531 | 341 | |
94ec8c6b | 342 | if (authctxt->valid == 0) |
343 | return(0); | |
344 | ||
345 | #ifdef HAVE_CYGWIN | |
346 | if (check_nt_auth(1, authctxt->pw->pw_uid) == 0) | |
347 | return(0); | |
348 | #endif | |
a306f2dd | 349 | #ifdef USE_PAM |
94ec8c6b | 350 | return auth_pam_password(authctxt->pw, ""); |
4d33e531 | 351 | #elif defined(HAVE_OSF_SIA) |
94ec8c6b | 352 | return (sia_validate_user(NULL, saved_argc, saved_argv, |
606ea390 | 353 | get_canonical_hostname(), authctxt->user?authctxt->user:"NOUSER", |
354 | NULL, 0, NULL, "") == SIASUCCESS); | |
4d33e531 | 355 | #else /* !HAVE_OSF_SIA && !USE_PAM */ |
94ec8c6b | 356 | return auth_password(authctxt->pw, ""); |
a306f2dd | 357 | #endif /* USE_PAM */ |
358 | } | |
94ec8c6b | 359 | |
a306f2dd | 360 | int |
94ec8c6b | 361 | userauth_passwd(Authctxt *authctxt) |
a306f2dd | 362 | { |
363 | char *password; | |
364 | int authenticated = 0; | |
365 | int change; | |
1e3b8b07 | 366 | u_int len; |
a306f2dd | 367 | change = packet_get_char(); |
368 | if (change) | |
369 | log("password change not supported"); | |
370 | password = packet_get_string(&len); | |
371 | packet_done(); | |
94ec8c6b | 372 | if (authctxt->valid && |
373 | #ifdef HAVE_CYGWIN | |
374 | check_nt_auth(1, authctxt->pw->pw_uid) && | |
375 | #endif | |
a306f2dd | 376 | #ifdef USE_PAM |
94ec8c6b | 377 | auth_pam_password(authctxt->pw, password) == 1) |
4d33e531 | 378 | #elif defined(HAVE_OSF_SIA) |
379 | sia_validate_user(NULL, saved_argc, saved_argv, | |
606ea390 | 380 | get_canonical_hostname(), authctxt->user?authctxt->user:"NOUSER", |
381 | NULL, 0, NULL, password) == SIASUCCESS) | |
4d33e531 | 382 | #else /* !USE_PAM && !HAVE_OSF_SIA */ |
94ec8c6b | 383 | auth_password(authctxt->pw, password) == 1) |
a306f2dd | 384 | #endif /* USE_PAM */ |
385 | authenticated = 1; | |
386 | memset(password, 0, len); | |
387 | xfree(password); | |
388 | return authenticated; | |
389 | } | |
94ec8c6b | 390 | |
391 | int | |
392 | userauth_kbdint(Authctxt *authctxt) | |
393 | { | |
394 | int authenticated = 0; | |
395 | char *lang = NULL; | |
396 | char *devs = NULL; | |
397 | ||
398 | lang = packet_get_string(NULL); | |
399 | devs = packet_get_string(NULL); | |
400 | packet_done(); | |
401 | ||
402 | debug("keyboard-interactive language %s devs %s", lang, devs); | |
59c97189 | 403 | |
404 | authenticated = auth2_challenge(authctxt, devs); | |
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(); | |
508 | authenticated = -1; | |
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); |
089fbbd2 | 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); | |
698 | return found_key; | |
699 | } |