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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" |
5ba55ada | 26 | RCSID("$OpenBSD: auth2.c,v 1.57 2001/05/18 14:13:28 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" |
8002af61 | 51 | #include "hostfile.h" |
52 | #include "canohost.h" | |
53 | #include "tildexpand.h" | |
5ba55ada | 54 | #include "match.h" |
a306f2dd | 55 | |
56 | /* import */ | |
57 | extern ServerOptions options; | |
1e3b8b07 | 58 | extern u_char *session_id2; |
a306f2dd | 59 | extern int session_id2_len; |
60 | ||
94ec8c6b | 61 | #ifdef WITH_AIXAUTHENTICATE |
62 | extern char *aixloginmsg; | |
63 | #endif | |
94ec8c6b | 64 | |
65 | static Authctxt *x_authctxt = NULL; | |
66 | static int one = 1; | |
67 | ||
68 | typedef struct Authmethod Authmethod; | |
69 | struct Authmethod { | |
70 | char *name; | |
71 | int (*userauth)(Authctxt *authctxt); | |
72 | int *enabled; | |
73 | }; | |
74 | ||
a306f2dd | 75 | /* protocol */ |
76 | ||
188adeb2 | 77 | void input_service_request(int type, int plen, void *ctxt); |
78 | void input_userauth_request(int type, int plen, void *ctxt); | |
79 | void protocol_error(int type, int plen, void *ctxt); | |
a306f2dd | 80 | |
a306f2dd | 81 | /* helper */ |
94ec8c6b | 82 | Authmethod *authmethod_lookup(const char *name); |
94ec8c6b | 83 | char *authmethods_get(void); |
8002af61 | 84 | int user_key_allowed(struct passwd *pw, Key *key); |
85 | int | |
57a5edd8 | 86 | hostbased_key_allowed(struct passwd *pw, const char *cuser, char *chost, |
8002af61 | 87 | Key *key); |
a306f2dd | 88 | |
94ec8c6b | 89 | /* auth */ |
eea39c02 | 90 | void userauth_banner(void); |
d9cd3575 | 91 | void userauth_reply(Authctxt *authctxt, int authenticated); |
94ec8c6b | 92 | int userauth_none(Authctxt *authctxt); |
93 | int userauth_passwd(Authctxt *authctxt); | |
94 | int userauth_pubkey(Authctxt *authctxt); | |
8002af61 | 95 | int userauth_hostbased(Authctxt *authctxt); |
94ec8c6b | 96 | int userauth_kbdint(Authctxt *authctxt); |
97 | ||
98 | Authmethod authmethods[] = { | |
99 | {"none", | |
100 | userauth_none, | |
101 | &one}, | |
102 | {"publickey", | |
103 | userauth_pubkey, | |
fa08c86b | 104 | &options.pubkey_authentication}, |
94ec8c6b | 105 | {"password", |
106 | userauth_passwd, | |
107 | &options.password_authentication}, | |
c845316f | 108 | {"keyboard-interactive", |
109 | userauth_kbdint, | |
110 | &options.kbd_interactive_authentication}, | |
8002af61 | 111 | {"hostbased", |
112 | userauth_hostbased, | |
113 | &options.hostbased_authentication}, | |
94ec8c6b | 114 | {NULL, NULL, NULL} |
a306f2dd | 115 | }; |
a306f2dd | 116 | |
117 | /* | |
94ec8c6b | 118 | * loop until authctxt->success == TRUE |
a306f2dd | 119 | */ |
120 | ||
121 | void | |
122 | do_authentication2() | |
123 | { | |
59c97189 | 124 | Authctxt *authctxt = authctxt_new(); |
125 | ||
94ec8c6b | 126 | x_authctxt = authctxt; /*XXX*/ |
127 | ||
d464095c | 128 | /* challenge-reponse is implemented via keyboard interactive */ |
5ba55ada | 129 | if (options.challenge_response_authentication) |
d464095c | 130 | options.kbd_interactive_authentication = 1; |
10f72868 | 131 | if (options.pam_authentication_via_kbd_int) |
132 | options.kbd_interactive_authentication = 1; | |
d464095c | 133 | |
a306f2dd | 134 | dispatch_init(&protocol_error); |
135 | dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request); | |
94ec8c6b | 136 | dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt); |
bb5639fe | 137 | do_authenticated(authctxt); |
a306f2dd | 138 | } |
139 | ||
140 | void | |
188adeb2 | 141 | protocol_error(int type, int plen, void *ctxt) |
a306f2dd | 142 | { |
143 | log("auth: protocol error: type %d plen %d", type, plen); | |
144 | packet_start(SSH2_MSG_UNIMPLEMENTED); | |
145 | packet_put_int(0); | |
146 | packet_send(); | |
147 | packet_write_wait(); | |
148 | } | |
149 | ||
150 | void | |
188adeb2 | 151 | input_service_request(int type, int plen, void *ctxt) |
a306f2dd | 152 | { |
94ec8c6b | 153 | Authctxt *authctxt = ctxt; |
1e3b8b07 | 154 | u_int len; |
a306f2dd | 155 | int accept = 0; |
156 | char *service = packet_get_string(&len); | |
157 | packet_done(); | |
158 | ||
94ec8c6b | 159 | if (authctxt == NULL) |
160 | fatal("input_service_request: no authctxt"); | |
161 | ||
a306f2dd | 162 | if (strcmp(service, "ssh-userauth") == 0) { |
94ec8c6b | 163 | if (!authctxt->success) { |
a306f2dd | 164 | accept = 1; |
165 | /* now we can handle user-auth requests */ | |
166 | dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request); | |
167 | } | |
168 | } | |
169 | /* XXX all other service requests are denied */ | |
170 | ||
171 | if (accept) { | |
172 | packet_start(SSH2_MSG_SERVICE_ACCEPT); | |
173 | packet_put_cstring(service); | |
174 | packet_send(); | |
175 | packet_write_wait(); | |
176 | } else { | |
177 | debug("bad service request %s", service); | |
178 | packet_disconnect("bad service request %s", service); | |
179 | } | |
180 | xfree(service); | |
181 | } | |
182 | ||
183 | void | |
188adeb2 | 184 | input_userauth_request(int type, int plen, void *ctxt) |
a306f2dd | 185 | { |
94ec8c6b | 186 | Authctxt *authctxt = ctxt; |
187 | Authmethod *m = NULL; | |
59c97189 | 188 | char *user, *service, *method, *style = NULL; |
a306f2dd | 189 | int authenticated = 0; |
a306f2dd | 190 | |
94ec8c6b | 191 | if (authctxt == NULL) |
192 | fatal("input_userauth_request: no authctxt"); | |
a306f2dd | 193 | |
94ec8c6b | 194 | user = packet_get_string(NULL); |
195 | service = packet_get_string(NULL); | |
196 | method = packet_get_string(NULL); | |
197 | debug("userauth-request for user %s service %s method %s", user, service, method); | |
8abcdba4 | 198 | debug("attempt %d failures %d", authctxt->attempt, authctxt->failures); |
94ec8c6b | 199 | |
59c97189 | 200 | if ((style = strchr(user, ':')) != NULL) |
201 | *style++ = 0; | |
202 | ||
2b87da3b | 203 | if (authctxt->attempt++ == 0) { |
94ec8c6b | 204 | /* setup auth context */ |
205 | struct passwd *pw = NULL; | |
94ec8c6b | 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 | } |
6172e290 | 220 | setproctitle("%s", pw ? user : "unknown"); |
94ec8c6b | 221 | authctxt->user = xstrdup(user); |
222 | authctxt->service = xstrdup(service); | |
59c97189 | 223 | authctxt->style = style ? xstrdup(style) : NULL; /* currently unused */ |
94ec8c6b | 224 | } else if (authctxt->valid) { |
225 | if (strcmp(user, authctxt->user) != 0 || | |
226 | strcmp(service, authctxt->service) != 0) { | |
8002af61 | 227 | log("input_userauth_request: mismatch: (%s,%s)!=(%s,%s)", |
94ec8c6b | 228 | user, service, authctxt->user, authctxt->service); |
229 | authctxt->valid = 0; | |
a306f2dd | 230 | } |
231 | } | |
59c97189 | 232 | /* reset state */ |
233 | dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE, &protocol_error); | |
234 | authctxt->postponed = 0; | |
af774732 | 235 | #ifdef BSD_AUTH |
236 | if (authctxt->as) { | |
237 | auth_close(authctxt->as); | |
238 | authctxt->as = NULL; | |
239 | } | |
240 | #endif | |
9cd45ea4 | 241 | |
59c97189 | 242 | /* try to authenticate user */ |
94ec8c6b | 243 | m = authmethod_lookup(method); |
244 | if (m != NULL) { | |
245 | debug2("input_userauth_request: try method %s", method); | |
246 | authenticated = m->userauth(authctxt); | |
9cd45ea4 | 247 | } |
d9cd3575 | 248 | userauth_finish(authctxt, authenticated, method); |
249 | ||
250 | xfree(service); | |
251 | xfree(user); | |
252 | xfree(method); | |
253 | } | |
254 | ||
255 | void | |
256 | userauth_finish(Authctxt *authctxt, int authenticated, char *method) | |
257 | { | |
59c97189 | 258 | if (!authctxt->valid && authenticated) |
259 | fatal("INTERNAL ERROR: authenticated invalid user %s", | |
260 | authctxt->user); | |
9cd45ea4 | 261 | |
94ec8c6b | 262 | /* Special handling for root */ |
15853e93 | 263 | if (authenticated && authctxt->pw->pw_uid == 0 && |
264 | !auth_root_allowed(method)) | |
a306f2dd | 265 | authenticated = 0; |
a306f2dd | 266 | |
267 | #ifdef USE_PAM | |
edef62bf | 268 | if (authenticated && authctxt->user && !do_pam_account(authctxt->user, |
269 | NULL)) | |
9cd45ea4 | 270 | authenticated = 0; |
a306f2dd | 271 | #endif /* USE_PAM */ |
272 | ||
94ec8c6b | 273 | /* Log before sending the reply */ |
59c97189 | 274 | auth_log(authctxt, authenticated, method, " ssh2"); |
275 | ||
276 | if (!authctxt->postponed) | |
277 | userauth_reply(authctxt, authenticated); | |
94ec8c6b | 278 | } |
279 | ||
eea39c02 | 280 | void |
281 | userauth_banner(void) | |
282 | { | |
283 | struct stat st; | |
284 | char *banner = NULL; | |
285 | off_t len, n; | |
286 | int fd; | |
287 | ||
288 | if (options.banner == NULL || (datafellows & SSH_BUG_BANNER)) | |
289 | return; | |
0715ec6c | 290 | if ((fd = open(options.banner, O_RDONLY)) < 0) |
eea39c02 | 291 | return; |
eea39c02 | 292 | if (fstat(fd, &st) < 0) |
293 | goto done; | |
294 | len = st.st_size; | |
295 | banner = xmalloc(len + 1); | |
296 | if ((n = read(fd, banner, len)) < 0) | |
297 | goto done; | |
298 | banner[n] = '\0'; | |
299 | packet_start(SSH2_MSG_USERAUTH_BANNER); | |
300 | packet_put_cstring(banner); | |
301 | packet_put_cstring(""); /* language, unused */ | |
302 | packet_send(); | |
303 | debug("userauth_banner: sent"); | |
304 | done: | |
305 | if (banner) | |
306 | xfree(banner); | |
307 | close(fd); | |
308 | return; | |
309 | } | |
94ec8c6b | 310 | |
2b87da3b | 311 | void |
94ec8c6b | 312 | userauth_reply(Authctxt *authctxt, int authenticated) |
313 | { | |
8abcdba4 | 314 | char *methods; |
59c97189 | 315 | |
1d1ffb87 | 316 | /* XXX todo: check if multiple auth methods are needed */ |
25f4c264 | 317 | if (authenticated == 1) { |
c1ef8333 | 318 | #ifdef WITH_AIXAUTHENTICATE |
319 | /* We don't have a pty yet, so just label the line as "ssh" */ | |
2b87da3b | 320 | if (loginsuccess(authctxt->user?authctxt->user:"NOUSER", |
321 | get_canonical_hostname(options.reverse_mapping_check), | |
61e96248 | 322 | "ssh", &aixloginmsg) < 0) |
c1ef8333 | 323 | aixloginmsg = NULL; |
324 | #endif /* WITH_AIXAUTHENTICATE */ | |
a306f2dd | 325 | /* turn off userauth */ |
326 | dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &protocol_error); | |
327 | packet_start(SSH2_MSG_USERAUTH_SUCCESS); | |
328 | packet_send(); | |
329 | packet_write_wait(); | |
330 | /* now we can break out */ | |
94ec8c6b | 331 | authctxt->success = 1; |
59c97189 | 332 | } else { |
333 | if (authctxt->failures++ > AUTH_FAIL_MAX) | |
2b87da3b | 334 | packet_disconnect(AUTH_FAIL_MSG, authctxt->user); |
8abcdba4 | 335 | methods = authmethods_get(); |
a306f2dd | 336 | packet_start(SSH2_MSG_USERAUTH_FAILURE); |
94ec8c6b | 337 | packet_put_cstring(methods); |
338 | packet_put_char(0); /* XXX partial success, unused */ | |
a306f2dd | 339 | packet_send(); |
340 | packet_write_wait(); | |
94ec8c6b | 341 | xfree(methods); |
a306f2dd | 342 | } |
a306f2dd | 343 | } |
344 | ||
345 | int | |
94ec8c6b | 346 | userauth_none(Authctxt *authctxt) |
a306f2dd | 347 | { |
94ec8c6b | 348 | /* disable method "none", only allowed one time */ |
349 | Authmethod *m = authmethod_lookup("none"); | |
350 | if (m != NULL) | |
351 | m->enabled = NULL; | |
a306f2dd | 352 | packet_done(); |
2b87da3b | 353 | userauth_banner(); |
4d33e531 | 354 | |
94ec8c6b | 355 | if (authctxt->valid == 0) |
356 | return(0); | |
2b87da3b | 357 | |
94ec8c6b | 358 | #ifdef HAVE_CYGWIN |
359 | if (check_nt_auth(1, authctxt->pw->pw_uid) == 0) | |
360 | return(0); | |
361 | #endif | |
a306f2dd | 362 | #ifdef USE_PAM |
94ec8c6b | 363 | return auth_pam_password(authctxt->pw, ""); |
4d33e531 | 364 | #elif defined(HAVE_OSF_SIA) |
b7ccb051 | 365 | return 0; |
4d33e531 | 366 | #else /* !HAVE_OSF_SIA && !USE_PAM */ |
af774732 | 367 | return auth_password(authctxt, ""); |
a306f2dd | 368 | #endif /* USE_PAM */ |
369 | } | |
94ec8c6b | 370 | |
a306f2dd | 371 | int |
94ec8c6b | 372 | userauth_passwd(Authctxt *authctxt) |
a306f2dd | 373 | { |
374 | char *password; | |
375 | int authenticated = 0; | |
376 | int change; | |
1e3b8b07 | 377 | u_int len; |
a306f2dd | 378 | change = packet_get_char(); |
379 | if (change) | |
380 | log("password change not supported"); | |
381 | password = packet_get_string(&len); | |
382 | packet_done(); | |
94ec8c6b | 383 | if (authctxt->valid && |
384 | #ifdef HAVE_CYGWIN | |
385 | check_nt_auth(1, authctxt->pw->pw_uid) && | |
386 | #endif | |
a306f2dd | 387 | #ifdef USE_PAM |
94ec8c6b | 388 | auth_pam_password(authctxt->pw, password) == 1) |
4d33e531 | 389 | #elif defined(HAVE_OSF_SIA) |
b7ccb051 | 390 | auth_sia_password(authctxt->user, password) == 1) |
4d33e531 | 391 | #else /* !USE_PAM && !HAVE_OSF_SIA */ |
af774732 | 392 | auth_password(authctxt, password) == 1) |
a306f2dd | 393 | #endif /* USE_PAM */ |
394 | authenticated = 1; | |
395 | memset(password, 0, len); | |
396 | xfree(password); | |
397 | return authenticated; | |
398 | } | |
94ec8c6b | 399 | |
400 | int | |
401 | userauth_kbdint(Authctxt *authctxt) | |
402 | { | |
403 | int authenticated = 0; | |
5ba55ada | 404 | char *lang, *devs; |
94ec8c6b | 405 | |
406 | lang = packet_get_string(NULL); | |
407 | devs = packet_get_string(NULL); | |
408 | packet_done(); | |
409 | ||
5ba55ada | 410 | debug("keyboard-interactive devs %s", devs); |
59c97189 | 411 | |
5ba55ada | 412 | if (options.challenge_response_authentication) |
d464095c | 413 | authenticated = auth2_challenge(authctxt, devs); |
59c97189 | 414 | |
8c9fe09e | 415 | #ifdef USE_PAM |
10f72868 | 416 | if (authenticated == 0 && options.pam_authentication_via_kbd_int) |
8c9fe09e | 417 | authenticated = auth2_pam(authctxt); |
94ec8c6b | 418 | #endif |
94ec8c6b | 419 | xfree(devs); |
5ba55ada | 420 | xfree(lang); |
94ec8c6b | 421 | #ifdef HAVE_CYGWIN |
422 | if (check_nt_auth(0, authctxt->pw->pw_uid) == 0) | |
423 | return(0); | |
424 | #endif | |
425 | return authenticated; | |
426 | } | |
427 | ||
a306f2dd | 428 | int |
94ec8c6b | 429 | userauth_pubkey(Authctxt *authctxt) |
a306f2dd | 430 | { |
431 | Buffer b; | |
432 | Key *key; | |
433 | char *pkalg, *pkblob, *sig; | |
1e3b8b07 | 434 | u_int alen, blen, slen; |
fa08c86b | 435 | int have_sig, pktype; |
a306f2dd | 436 | int authenticated = 0; |
437 | ||
94ec8c6b | 438 | if (!authctxt->valid) { |
439 | debug2("userauth_pubkey: disabled because of invalid user"); | |
a306f2dd | 440 | return 0; |
441 | } | |
442 | have_sig = packet_get_char(); | |
cbc5abf9 | 443 | if (datafellows & SSH_BUG_PKAUTH) { |
444 | debug2("userauth_pubkey: SSH_BUG_PKAUTH"); | |
445 | /* no explicit pkalg given */ | |
446 | pkblob = packet_get_string(&blen); | |
447 | buffer_init(&b); | |
448 | buffer_append(&b, pkblob, blen); | |
449 | /* so we have to extract the pkalg from the pkblob */ | |
450 | pkalg = buffer_get_string(&b, &alen); | |
451 | buffer_free(&b); | |
452 | } else { | |
453 | pkalg = packet_get_string(&alen); | |
454 | pkblob = packet_get_string(&blen); | |
455 | } | |
fa08c86b | 456 | pktype = key_type_from_name(pkalg); |
457 | if (pktype == KEY_UNSPEC) { | |
cbc5abf9 | 458 | /* this is perfectly legal */ |
459 | log("userauth_pubkey: unsupported public key algorithm: %s", pkalg); | |
94ec8c6b | 460 | xfree(pkalg); |
cbc5abf9 | 461 | xfree(pkblob); |
a306f2dd | 462 | return 0; |
463 | } | |
fa08c86b | 464 | key = key_from_blob(pkblob, blen); |
a306f2dd | 465 | if (key != NULL) { |
466 | if (have_sig) { | |
467 | sig = packet_get_string(&slen); | |
468 | packet_done(); | |
469 | buffer_init(&b); | |
33de75a3 | 470 | if (datafellows & SSH_OLD_SESSIONID) { |
74fc9186 | 471 | buffer_append(&b, session_id2, session_id2_len); |
33de75a3 | 472 | } else { |
473 | buffer_put_string(&b, session_id2, session_id2_len); | |
74fc9186 | 474 | } |
38c295d6 | 475 | /* reconstruct packet */ |
a306f2dd | 476 | buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); |
94ec8c6b | 477 | buffer_put_cstring(&b, authctxt->user); |
38c295d6 | 478 | buffer_put_cstring(&b, |
cbc5abf9 | 479 | datafellows & SSH_BUG_PKSERVICE ? |
38c295d6 | 480 | "ssh-userauth" : |
94ec8c6b | 481 | authctxt->service); |
cbc5abf9 | 482 | if (datafellows & SSH_BUG_PKAUTH) { |
483 | buffer_put_char(&b, have_sig); | |
484 | } else { | |
485 | buffer_put_cstring(&b, "publickey"); | |
486 | buffer_put_char(&b, have_sig); | |
5cf13595 | 487 | buffer_put_cstring(&b, pkalg); |
cbc5abf9 | 488 | } |
38c295d6 | 489 | buffer_put_string(&b, pkblob, blen); |
fa08c86b | 490 | #ifdef DEBUG_PK |
a306f2dd | 491 | buffer_dump(&b); |
492 | #endif | |
493 | /* test for correct signature */ | |
fa08c86b | 494 | if (user_key_allowed(authctxt->pw, key) && |
495 | key_verify(key, sig, slen, buffer_ptr(&b), buffer_len(&b)) == 1) | |
a306f2dd | 496 | authenticated = 1; |
497 | buffer_clear(&b); | |
498 | xfree(sig); | |
499 | } else { | |
94ec8c6b | 500 | debug("test whether pkalg/pkblob are acceptable"); |
a306f2dd | 501 | packet_done(); |
94ec8c6b | 502 | |
a306f2dd | 503 | /* XXX fake reply and always send PK_OK ? */ |
1d1ffb87 | 504 | /* |
505 | * XXX this allows testing whether a user is allowed | |
506 | * to login: if you happen to have a valid pubkey this | |
507 | * message is sent. the message is NEVER sent at all | |
508 | * if a user is not allowed to login. is this an | |
509 | * issue? -markus | |
510 | */ | |
fa08c86b | 511 | if (user_key_allowed(authctxt->pw, key)) { |
a306f2dd | 512 | packet_start(SSH2_MSG_USERAUTH_PK_OK); |
513 | packet_put_string(pkalg, alen); | |
514 | packet_put_string(pkblob, blen); | |
515 | packet_send(); | |
516 | packet_write_wait(); | |
25f4c264 | 517 | authctxt->postponed = 1; |
a306f2dd | 518 | } |
519 | } | |
94ec8c6b | 520 | if (authenticated != 1) |
521 | auth_clear_options(); | |
a306f2dd | 522 | key_free(key); |
523 | } | |
fa08c86b | 524 | debug2("userauth_pubkey: authenticated %d pkalg %s", authenticated, pkalg); |
a306f2dd | 525 | xfree(pkalg); |
526 | xfree(pkblob); | |
94ec8c6b | 527 | #ifdef HAVE_CYGWIN |
528 | if (check_nt_auth(0, authctxt->pw->pw_uid) == 0) | |
529 | return(0); | |
530 | #endif | |
a306f2dd | 531 | return authenticated; |
532 | } | |
533 | ||
8002af61 | 534 | int |
535 | userauth_hostbased(Authctxt *authctxt) | |
536 | { | |
537 | Buffer b; | |
538 | Key *key; | |
8dddf799 | 539 | char *pkalg, *pkblob, *sig, *cuser, *chost, *service; |
8002af61 | 540 | u_int alen, blen, slen; |
541 | int pktype; | |
542 | int authenticated = 0; | |
543 | ||
544 | if (!authctxt->valid) { | |
545 | debug2("userauth_hostbased: disabled because of invalid user"); | |
546 | return 0; | |
547 | } | |
548 | pkalg = packet_get_string(&alen); | |
549 | pkblob = packet_get_string(&blen); | |
550 | chost = packet_get_string(NULL); | |
551 | cuser = packet_get_string(NULL); | |
552 | sig = packet_get_string(&slen); | |
553 | ||
554 | debug("userauth_hostbased: cuser %s chost %s pkalg %s slen %d", | |
555 | cuser, chost, pkalg, slen); | |
556 | #ifdef DEBUG_PK | |
557 | debug("signature:"); | |
558 | buffer_init(&b); | |
559 | buffer_append(&b, sig, slen); | |
560 | buffer_dump(&b); | |
561 | buffer_free(&b); | |
562 | #endif | |
563 | pktype = key_type_from_name(pkalg); | |
564 | if (pktype == KEY_UNSPEC) { | |
565 | /* this is perfectly legal */ | |
566 | log("userauth_hostbased: unsupported " | |
567 | "public key algorithm: %s", pkalg); | |
568 | goto done; | |
569 | } | |
570 | key = key_from_blob(pkblob, blen); | |
571 | if (key == NULL) { | |
572 | debug("userauth_hostbased: cannot decode key: %s", pkalg); | |
573 | goto done; | |
574 | } | |
8dddf799 | 575 | service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" : |
576 | authctxt->service; | |
8002af61 | 577 | buffer_init(&b); |
8dddf799 | 578 | buffer_put_string(&b, session_id2, session_id2_len); |
8002af61 | 579 | /* reconstruct packet */ |
580 | buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); | |
581 | buffer_put_cstring(&b, authctxt->user); | |
8dddf799 | 582 | buffer_put_cstring(&b, service); |
8002af61 | 583 | buffer_put_cstring(&b, "hostbased"); |
584 | buffer_put_string(&b, pkalg, alen); | |
585 | buffer_put_string(&b, pkblob, blen); | |
586 | buffer_put_cstring(&b, chost); | |
587 | buffer_put_cstring(&b, cuser); | |
588 | #ifdef DEBUG_PK | |
589 | buffer_dump(&b); | |
590 | #endif | |
591 | /* test for allowed key and correct signature */ | |
592 | if (hostbased_key_allowed(authctxt->pw, cuser, chost, key) && | |
593 | key_verify(key, sig, slen, buffer_ptr(&b), buffer_len(&b)) == 1) | |
594 | authenticated = 1; | |
595 | ||
596 | buffer_clear(&b); | |
597 | key_free(key); | |
598 | ||
599 | done: | |
600 | debug2("userauth_hostbased: authenticated %d", authenticated); | |
601 | xfree(pkalg); | |
602 | xfree(pkblob); | |
603 | xfree(cuser); | |
604 | xfree(chost); | |
605 | xfree(sig); | |
606 | return authenticated; | |
607 | } | |
608 | ||
94ec8c6b | 609 | /* get current user */ |
a306f2dd | 610 | |
611 | struct passwd* | |
612 | auth_get_user(void) | |
613 | { | |
94ec8c6b | 614 | return (x_authctxt != NULL && x_authctxt->valid) ? x_authctxt->pw : NULL; |
a306f2dd | 615 | } |
616 | ||
94ec8c6b | 617 | #define DELIM "," |
618 | ||
619 | char * | |
620 | authmethods_get(void) | |
a306f2dd | 621 | { |
94ec8c6b | 622 | Authmethod *method = NULL; |
1e3b8b07 | 623 | u_int size = 0; |
94ec8c6b | 624 | char *list; |
625 | ||
626 | for (method = authmethods; method->name != NULL; method++) { | |
627 | if (strcmp(method->name, "none") == 0) | |
628 | continue; | |
629 | if (method->enabled != NULL && *(method->enabled) != 0) { | |
630 | if (size != 0) | |
631 | size += strlen(DELIM); | |
632 | size += strlen(method->name); | |
a306f2dd | 633 | } |
94ec8c6b | 634 | } |
635 | size++; /* trailing '\0' */ | |
636 | list = xmalloc(size); | |
637 | list[0] = '\0'; | |
638 | ||
639 | for (method = authmethods; method->name != NULL; method++) { | |
640 | if (strcmp(method->name, "none") == 0) | |
641 | continue; | |
642 | if (method->enabled != NULL && *(method->enabled) != 0) { | |
643 | if (list[0] != '\0') | |
644 | strlcat(list, DELIM, size); | |
645 | strlcat(list, method->name, size); | |
a306f2dd | 646 | } |
647 | } | |
94ec8c6b | 648 | return list; |
649 | } | |
650 | ||
651 | Authmethod * | |
652 | authmethod_lookup(const char *name) | |
653 | { | |
654 | Authmethod *method = NULL; | |
655 | if (name != NULL) | |
656 | for (method = authmethods; method->name != NULL; method++) | |
657 | if (method->enabled != NULL && | |
658 | *(method->enabled) != 0 && | |
659 | strcmp(name, method->name) == 0) | |
660 | return method; | |
661 | debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); | |
662 | return NULL; | |
a306f2dd | 663 | } |
664 | ||
665 | /* return 1 if user allows given key */ | |
666 | int | |
fa08c86b | 667 | user_key_allowed(struct passwd *pw, Key *key) |
a306f2dd | 668 | { |
42f11eb2 | 669 | char line[8192], file[MAXPATHLEN]; |
a306f2dd | 670 | int found_key = 0; |
a306f2dd | 671 | FILE *f; |
1e3b8b07 | 672 | u_long linenum = 0; |
a306f2dd | 673 | struct stat st; |
674 | Key *found; | |
675 | ||
94ec8c6b | 676 | if (pw == NULL) |
677 | return 0; | |
678 | ||
a306f2dd | 679 | /* Temporarily use the user's uid. */ |
63bd8c36 | 680 | temporarily_use_uid(pw); |
a306f2dd | 681 | |
682 | /* The authorized keys. */ | |
683 | snprintf(file, sizeof file, "%.500s/%.100s", pw->pw_dir, | |
42f11eb2 | 684 | _PATH_SSH_USER_PERMITTED_KEYS2); |
a306f2dd | 685 | |
686 | /* Fail quietly if file does not exist */ | |
687 | if (stat(file, &st) < 0) { | |
688 | /* Restore the privileged uid. */ | |
689 | restore_uid(); | |
690 | return 0; | |
691 | } | |
692 | /* Open the file containing the authorized keys. */ | |
693 | f = fopen(file, "r"); | |
694 | if (!f) { | |
695 | /* Restore the privileged uid. */ | |
696 | restore_uid(); | |
697 | return 0; | |
698 | } | |
699 | if (options.strict_modes) { | |
700 | int fail = 0; | |
701 | char buf[1024]; | |
702 | /* Check open file in order to avoid open/stat races */ | |
703 | if (fstat(fileno(f), &st) < 0 || | |
704 | (st.st_uid != 0 && st.st_uid != pw->pw_uid) || | |
705 | (st.st_mode & 022) != 0) { | |
de273eef | 706 | snprintf(buf, sizeof buf, |
707 | "%s authentication refused for %.100s: " | |
708 | "bad ownership or modes for '%s'.", | |
709 | key_type(key), pw->pw_name, file); | |
a306f2dd | 710 | fail = 1; |
711 | } else { | |
42f11eb2 | 712 | /* Check path to _PATH_SSH_USER_PERMITTED_KEYS */ |
a306f2dd | 713 | int i; |
714 | static const char *check[] = { | |
42f11eb2 | 715 | "", _PATH_SSH_USER_DIR, NULL |
a306f2dd | 716 | }; |
717 | for (i = 0; check[i]; i++) { | |
718 | snprintf(line, sizeof line, "%.500s/%.100s", | |
719 | pw->pw_dir, check[i]); | |
720 | if (stat(line, &st) < 0 || | |
721 | (st.st_uid != 0 && st.st_uid != pw->pw_uid) || | |
722 | (st.st_mode & 022) != 0) { | |
723 | snprintf(buf, sizeof buf, | |
de273eef | 724 | "%s authentication refused for %.100s: " |
a306f2dd | 725 | "bad ownership or modes for '%s'.", |
de273eef | 726 | key_type(key), pw->pw_name, line); |
a306f2dd | 727 | fail = 1; |
728 | break; | |
729 | } | |
730 | } | |
731 | } | |
732 | if (fail) { | |
a306f2dd | 733 | fclose(f); |
12bf85ed | 734 | log("%s", buf); |
a306f2dd | 735 | restore_uid(); |
736 | return 0; | |
737 | } | |
738 | } | |
739 | found_key = 0; | |
de273eef | 740 | found = key_new(key->type); |
a306f2dd | 741 | |
742 | while (fgets(line, sizeof(line), f)) { | |
38c295d6 | 743 | char *cp, *options = NULL; |
a306f2dd | 744 | linenum++; |
745 | /* Skip leading whitespace, empty and comment lines. */ | |
746 | for (cp = line; *cp == ' ' || *cp == '\t'; cp++) | |
747 | ; | |
748 | if (!*cp || *cp == '\n' || *cp == '#') | |
749 | continue; | |
38c295d6 | 750 | |
fa08c86b | 751 | if (key_read(found, &cp) == -1) { |
38c295d6 | 752 | /* no key? check if there are options for this key */ |
753 | int quoted = 0; | |
fa08c86b | 754 | debug2("user_key_allowed: check options: '%s'", cp); |
38c295d6 | 755 | options = cp; |
756 | for (; *cp && (quoted || (*cp != ' ' && *cp != '\t')); cp++) { | |
757 | if (*cp == '\\' && cp[1] == '"') | |
758 | cp++; /* Skip both */ | |
759 | else if (*cp == '"') | |
760 | quoted = !quoted; | |
761 | } | |
762 | /* Skip remaining whitespace. */ | |
763 | for (; *cp == ' ' || *cp == '\t'; cp++) | |
764 | ; | |
fa08c86b | 765 | if (key_read(found, &cp) == -1) { |
766 | debug2("user_key_allowed: advance: '%s'", cp); | |
38c295d6 | 767 | /* still no key? advance to next line*/ |
768 | continue; | |
769 | } | |
770 | } | |
771 | if (key_equal(found, key) && | |
42f11eb2 | 772 | auth_parse_options(pw, options, file, linenum) == 1) { |
a306f2dd | 773 | found_key = 1; |
774 | debug("matching key found: file %s, line %ld", | |
775 | file, linenum); | |
776 | break; | |
777 | } | |
778 | } | |
779 | restore_uid(); | |
780 | fclose(f); | |
781 | key_free(found); | |
539af7f5 | 782 | if (!found_key) |
783 | debug2("key not found"); | |
a306f2dd | 784 | return found_key; |
785 | } | |
8002af61 | 786 | |
787 | /* return 1 if given hostkey is allowed */ | |
788 | int | |
57a5edd8 | 789 | hostbased_key_allowed(struct passwd *pw, const char *cuser, char *chost, |
8002af61 | 790 | Key *key) |
791 | { | |
792 | Key *found; | |
793 | const char *resolvedname, *ipaddr, *lookup; | |
794 | struct stat st; | |
795 | char *user_hostfile; | |
f98c3421 | 796 | int host_status, len; |
8002af61 | 797 | |
798 | resolvedname = get_canonical_hostname(options.reverse_mapping_check); | |
799 | ipaddr = get_remote_ipaddr(); | |
800 | ||
f98c3421 | 801 | debug2("userauth_hostbased: chost %s resolvedname %s ipaddr %s", |
802 | chost, resolvedname, ipaddr); | |
8002af61 | 803 | |
804 | if (options.hostbased_uses_name_from_packet_only) { | |
805 | if (auth_rhosts2(pw, cuser, chost, chost) == 0) | |
806 | return 0; | |
807 | lookup = chost; | |
808 | } else { | |
f98c3421 | 809 | if (((len = strlen(chost)) > 0) && chost[len - 1] == '.') { |
810 | debug2("stripping trailing dot from chost %s", chost); | |
811 | chost[len - 1] = '\0'; | |
812 | } | |
8002af61 | 813 | if (strcasecmp(resolvedname, chost) != 0) |
814 | log("userauth_hostbased mismatch: " | |
815 | "client sends %s, but we resolve %s to %s", | |
816 | chost, ipaddr, resolvedname); | |
817 | if (auth_rhosts2(pw, cuser, resolvedname, ipaddr) == 0) | |
818 | return 0; | |
819 | lookup = resolvedname; | |
820 | } | |
821 | debug2("userauth_hostbased: access allowed by auth_rhosts2"); | |
822 | ||
823 | /* XXX this is copied from auth-rh-rsa.c and should be shared */ | |
824 | found = key_new(key->type); | |
825 | host_status = check_host_in_hostfile(_PATH_SSH_SYSTEM_HOSTFILE2, lookup, | |
826 | key, found, NULL); | |
827 | ||
828 | if (host_status != HOST_OK && !options.ignore_user_known_hosts) { | |
829 | user_hostfile = tilde_expand_filename(_PATH_SSH_USER_HOSTFILE2, | |
830 | pw->pw_uid); | |
831 | if (options.strict_modes && | |
832 | (stat(user_hostfile, &st) == 0) && | |
833 | ((st.st_uid != 0 && st.st_uid != pw->pw_uid) || | |
834 | (st.st_mode & 022) != 0)) { | |
835 | log("Hostbased authentication refused for %.100s: " | |
836 | "bad owner or modes for %.200s", | |
837 | pw->pw_name, user_hostfile); | |
838 | } else { | |
839 | temporarily_use_uid(pw); | |
840 | host_status = check_host_in_hostfile(user_hostfile, | |
841 | lookup, key, found, NULL); | |
842 | restore_uid(); | |
843 | } | |
844 | xfree(user_hostfile); | |
845 | } | |
846 | key_free(found); | |
847 | ||
848 | debug2("userauth_hostbased: key %s for %s", host_status == HOST_OK ? | |
849 | "ok" : "not found", lookup); | |
850 | return (host_status == HOST_OK); | |
851 | } |