81
82/* import */
83extern ServerOptions options;
84extern int use_privsep;
85extern Buffer loginmsg;
86extern struct passwd *privsep_pw;
87
88/* Debugging messages */
89Buffer auth_debug;
90int auth_debug_init;
91
92/*
93 * Check if the user is allowed to log in via ssh. If user is listed
94 * in DenyUsers or one of user's groups is listed in DenyGroups, false
95 * will be returned. If AllowUsers isn't empty and user isn't listed
96 * there, or if AllowGroups isn't empty and one of user's groups isn't
97 * listed there, false will be returned.
98 * If the user's shell is not executable, false will be returned.
99 * Otherwise true is returned.
100 */
101int
102allowed_user(struct passwd * pw)
103{
104 struct stat st;
105 const char *hostname = NULL, *ipaddr = NULL, *passwd = NULL;
106 u_int i;
107#ifdef USE_SHADOW
108 struct spwd *spw = NULL;
109#endif
110
111 /* Shouldn't be called if pw is NULL, but better safe than sorry... */
112 if (!pw || !pw->pw_name)
113 return 0;
114
115#ifdef USE_SHADOW
116 if (!options.use_pam)
117 spw = getspnam(pw->pw_name);
118#ifdef HAS_SHADOW_EXPIRE
119 if (!options.use_pam && spw != NULL && auth_shadow_acctexpired(spw))
120 return 0;
121#endif /* HAS_SHADOW_EXPIRE */
122#endif /* USE_SHADOW */
123
124 /* grab passwd field for locked account check */
125 passwd = pw->pw_passwd;
126#ifdef USE_SHADOW
127 if (spw != NULL)
128#ifdef USE_LIBIAF
129 passwd = get_iaf_password(pw);
130#else
131 passwd = spw->sp_pwdp;
132#endif /* USE_LIBIAF */
133#endif
134
135 /* check for locked account */
136 if (!options.use_pam && passwd && *passwd) {
137 int locked = 0;
138
139#ifdef LOCKED_PASSWD_STRING
140 if (strcmp(passwd, LOCKED_PASSWD_STRING) == 0)
141 locked = 1;
142#endif
143#ifdef LOCKED_PASSWD_PREFIX
144 if (strncmp(passwd, LOCKED_PASSWD_PREFIX,
145 strlen(LOCKED_PASSWD_PREFIX)) == 0)
146 locked = 1;
147#endif
148#ifdef LOCKED_PASSWD_SUBSTR
149 if (strstr(passwd, LOCKED_PASSWD_SUBSTR))
150 locked = 1;
151#endif
152#ifdef USE_LIBIAF
153 free((void *) passwd);
154#endif /* USE_LIBIAF */
155 if (locked) {
156 logit("User %.100s not allowed because account is locked",
157 pw->pw_name);
158 return 0;
159 }
160 }
161
162 /*
163 * Deny if shell does not exist or is not executable unless we
164 * are chrooting.
165 */
166 if (options.chroot_directory == NULL ||
167 strcasecmp(options.chroot_directory, "none") == 0) {
168 char *shell = xstrdup((pw->pw_shell[0] == '\0') ?
169 _PATH_BSHELL : pw->pw_shell); /* empty = /bin/sh */
170
171 if (stat(shell, &st) != 0) {
172 logit("User %.100s not allowed because shell %.100s "
173 "does not exist", pw->pw_name, shell);
174 free(shell);
175 return 0;
176 }
177 if (S_ISREG(st.st_mode) == 0 ||
178 (st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP)) == 0) {
179 logit("User %.100s not allowed because shell %.100s "
180 "is not executable", pw->pw_name, shell);
181 free(shell);
182 return 0;
183 }
184 free(shell);
185 }
186
187 if (options.num_deny_users > 0 || options.num_allow_users > 0 ||
188 options.num_deny_groups > 0 || options.num_allow_groups > 0) {
189 hostname = get_canonical_hostname(options.use_dns);
190 ipaddr = get_remote_ipaddr();
191 }
192
193 /* Return false if user is listed in DenyUsers */
194 if (options.num_deny_users > 0) {
195 for (i = 0; i < options.num_deny_users; i++)
196 if (match_user(pw->pw_name, hostname, ipaddr,
197 options.deny_users[i])) {
198 logit("User %.100s from %.100s not allowed "
199 "because listed in DenyUsers",
200 pw->pw_name, hostname);
201 return 0;
202 }
203 }
204 /* Return false if AllowUsers isn't empty and user isn't listed there */
205 if (options.num_allow_users > 0) {
206 for (i = 0; i < options.num_allow_users; i++)
207 if (match_user(pw->pw_name, hostname, ipaddr,
208 options.allow_users[i]))
209 break;
210 /* i < options.num_allow_users iff we break for loop */
211 if (i >= options.num_allow_users) {
212 logit("User %.100s from %.100s not allowed because "
213 "not listed in AllowUsers", pw->pw_name, hostname);
214 return 0;
215 }
216 }
217 if (options.num_deny_groups > 0 || options.num_allow_groups > 0) {
218 /* Get the user's group access list (primary and supplementary) */
219 if (ga_init(pw->pw_name, pw->pw_gid) == 0) {
220 logit("User %.100s from %.100s not allowed because "
221 "not in any group", pw->pw_name, hostname);
222 return 0;
223 }
224
225 /* Return false if one of user's groups is listed in DenyGroups */
226 if (options.num_deny_groups > 0)
227 if (ga_match(options.deny_groups,
228 options.num_deny_groups)) {
229 ga_free();
230 logit("User %.100s from %.100s not allowed "
231 "because a group is listed in DenyGroups",
232 pw->pw_name, hostname);
233 return 0;
234 }
235 /*
236 * Return false if AllowGroups isn't empty and one of user's groups
237 * isn't listed there
238 */
239 if (options.num_allow_groups > 0)
240 if (!ga_match(options.allow_groups,
241 options.num_allow_groups)) {
242 ga_free();
243 logit("User %.100s from %.100s not allowed "
244 "because none of user's groups are listed "
245 "in AllowGroups", pw->pw_name, hostname);
246 return 0;
247 }
248 ga_free();
249 }
250
251#ifdef CUSTOM_SYS_AUTH_ALLOWED_USER
252 if (!sys_auth_allowed_user(pw, &loginmsg))
253 return 0;
254#endif
255
256 /* We found no reason not to let this user try to log on... */
257 return 1;
258}
259
260void
261auth_info(Authctxt *authctxt, const char *fmt, ...)
262{
263 va_list ap;
264 int i;
265
266 free(authctxt->info);
267 authctxt->info = NULL;
268
269 va_start(ap, fmt);
270 i = vasprintf(&authctxt->info, fmt, ap);
271 va_end(ap);
272
273 if (i < 0 || authctxt->info == NULL)
274 fatal("vasprintf failed");
275}
276
277void
278auth_log(Authctxt *authctxt, int authenticated, int partial,
279 const char *method, const char *submethod)
280{
281 void (*authlog) (const char *fmt,...) = verbose;
282 char *authmsg;
283
284 if (use_privsep && !mm_is_monitor() && !authctxt->postponed)
285 return;
286
287 /* Raise logging level */
288 if (authenticated == 1 ||
289 !authctxt->valid ||
290 authctxt->failures >= options.max_authtries / 2 ||
291 strcmp(method, "password") == 0)
292 authlog = logit;
293
294 if (authctxt->postponed)
295 authmsg = "Postponed";
296 else if (partial)
297 authmsg = "Partial";
298 else
299 authmsg = authenticated ? "Accepted" : "Failed";
300
301 authlog("%s %s%s%s for %s%.100s from %.200s port %d %s%s%s",
302 authmsg,
303 method,
304 submethod != NULL ? "/" : "", submethod == NULL ? "" : submethod,
305 authctxt->valid ? "" : "invalid user ",
306 authctxt->user,
307 get_remote_ipaddr(),
308 get_remote_port(),
309 compat20 ? "ssh2" : "ssh1",
310 authctxt->info != NULL ? ": " : "",
311 authctxt->info != NULL ? authctxt->info : "");
| 78
79/* import */
80extern ServerOptions options;
81extern int use_privsep;
82extern Buffer loginmsg;
83extern struct passwd *privsep_pw;
84
85/* Debugging messages */
86Buffer auth_debug;
87int auth_debug_init;
88
89/*
90 * Check if the user is allowed to log in via ssh. If user is listed
91 * in DenyUsers or one of user's groups is listed in DenyGroups, false
92 * will be returned. If AllowUsers isn't empty and user isn't listed
93 * there, or if AllowGroups isn't empty and one of user's groups isn't
94 * listed there, false will be returned.
95 * If the user's shell is not executable, false will be returned.
96 * Otherwise true is returned.
97 */
98int
99allowed_user(struct passwd * pw)
100{
101 struct stat st;
102 const char *hostname = NULL, *ipaddr = NULL, *passwd = NULL;
103 u_int i;
104#ifdef USE_SHADOW
105 struct spwd *spw = NULL;
106#endif
107
108 /* Shouldn't be called if pw is NULL, but better safe than sorry... */
109 if (!pw || !pw->pw_name)
110 return 0;
111
112#ifdef USE_SHADOW
113 if (!options.use_pam)
114 spw = getspnam(pw->pw_name);
115#ifdef HAS_SHADOW_EXPIRE
116 if (!options.use_pam && spw != NULL && auth_shadow_acctexpired(spw))
117 return 0;
118#endif /* HAS_SHADOW_EXPIRE */
119#endif /* USE_SHADOW */
120
121 /* grab passwd field for locked account check */
122 passwd = pw->pw_passwd;
123#ifdef USE_SHADOW
124 if (spw != NULL)
125#ifdef USE_LIBIAF
126 passwd = get_iaf_password(pw);
127#else
128 passwd = spw->sp_pwdp;
129#endif /* USE_LIBIAF */
130#endif
131
132 /* check for locked account */
133 if (!options.use_pam && passwd && *passwd) {
134 int locked = 0;
135
136#ifdef LOCKED_PASSWD_STRING
137 if (strcmp(passwd, LOCKED_PASSWD_STRING) == 0)
138 locked = 1;
139#endif
140#ifdef LOCKED_PASSWD_PREFIX
141 if (strncmp(passwd, LOCKED_PASSWD_PREFIX,
142 strlen(LOCKED_PASSWD_PREFIX)) == 0)
143 locked = 1;
144#endif
145#ifdef LOCKED_PASSWD_SUBSTR
146 if (strstr(passwd, LOCKED_PASSWD_SUBSTR))
147 locked = 1;
148#endif
149#ifdef USE_LIBIAF
150 free((void *) passwd);
151#endif /* USE_LIBIAF */
152 if (locked) {
153 logit("User %.100s not allowed because account is locked",
154 pw->pw_name);
155 return 0;
156 }
157 }
158
159 /*
160 * Deny if shell does not exist or is not executable unless we
161 * are chrooting.
162 */
163 if (options.chroot_directory == NULL ||
164 strcasecmp(options.chroot_directory, "none") == 0) {
165 char *shell = xstrdup((pw->pw_shell[0] == '\0') ?
166 _PATH_BSHELL : pw->pw_shell); /* empty = /bin/sh */
167
168 if (stat(shell, &st) != 0) {
169 logit("User %.100s not allowed because shell %.100s "
170 "does not exist", pw->pw_name, shell);
171 free(shell);
172 return 0;
173 }
174 if (S_ISREG(st.st_mode) == 0 ||
175 (st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP)) == 0) {
176 logit("User %.100s not allowed because shell %.100s "
177 "is not executable", pw->pw_name, shell);
178 free(shell);
179 return 0;
180 }
181 free(shell);
182 }
183
184 if (options.num_deny_users > 0 || options.num_allow_users > 0 ||
185 options.num_deny_groups > 0 || options.num_allow_groups > 0) {
186 hostname = get_canonical_hostname(options.use_dns);
187 ipaddr = get_remote_ipaddr();
188 }
189
190 /* Return false if user is listed in DenyUsers */
191 if (options.num_deny_users > 0) {
192 for (i = 0; i < options.num_deny_users; i++)
193 if (match_user(pw->pw_name, hostname, ipaddr,
194 options.deny_users[i])) {
195 logit("User %.100s from %.100s not allowed "
196 "because listed in DenyUsers",
197 pw->pw_name, hostname);
198 return 0;
199 }
200 }
201 /* Return false if AllowUsers isn't empty and user isn't listed there */
202 if (options.num_allow_users > 0) {
203 for (i = 0; i < options.num_allow_users; i++)
204 if (match_user(pw->pw_name, hostname, ipaddr,
205 options.allow_users[i]))
206 break;
207 /* i < options.num_allow_users iff we break for loop */
208 if (i >= options.num_allow_users) {
209 logit("User %.100s from %.100s not allowed because "
210 "not listed in AllowUsers", pw->pw_name, hostname);
211 return 0;
212 }
213 }
214 if (options.num_deny_groups > 0 || options.num_allow_groups > 0) {
215 /* Get the user's group access list (primary and supplementary) */
216 if (ga_init(pw->pw_name, pw->pw_gid) == 0) {
217 logit("User %.100s from %.100s not allowed because "
218 "not in any group", pw->pw_name, hostname);
219 return 0;
220 }
221
222 /* Return false if one of user's groups is listed in DenyGroups */
223 if (options.num_deny_groups > 0)
224 if (ga_match(options.deny_groups,
225 options.num_deny_groups)) {
226 ga_free();
227 logit("User %.100s from %.100s not allowed "
228 "because a group is listed in DenyGroups",
229 pw->pw_name, hostname);
230 return 0;
231 }
232 /*
233 * Return false if AllowGroups isn't empty and one of user's groups
234 * isn't listed there
235 */
236 if (options.num_allow_groups > 0)
237 if (!ga_match(options.allow_groups,
238 options.num_allow_groups)) {
239 ga_free();
240 logit("User %.100s from %.100s not allowed "
241 "because none of user's groups are listed "
242 "in AllowGroups", pw->pw_name, hostname);
243 return 0;
244 }
245 ga_free();
246 }
247
248#ifdef CUSTOM_SYS_AUTH_ALLOWED_USER
249 if (!sys_auth_allowed_user(pw, &loginmsg))
250 return 0;
251#endif
252
253 /* We found no reason not to let this user try to log on... */
254 return 1;
255}
256
257void
258auth_info(Authctxt *authctxt, const char *fmt, ...)
259{
260 va_list ap;
261 int i;
262
263 free(authctxt->info);
264 authctxt->info = NULL;
265
266 va_start(ap, fmt);
267 i = vasprintf(&authctxt->info, fmt, ap);
268 va_end(ap);
269
270 if (i < 0 || authctxt->info == NULL)
271 fatal("vasprintf failed");
272}
273
274void
275auth_log(Authctxt *authctxt, int authenticated, int partial,
276 const char *method, const char *submethod)
277{
278 void (*authlog) (const char *fmt,...) = verbose;
279 char *authmsg;
280
281 if (use_privsep && !mm_is_monitor() && !authctxt->postponed)
282 return;
283
284 /* Raise logging level */
285 if (authenticated == 1 ||
286 !authctxt->valid ||
287 authctxt->failures >= options.max_authtries / 2 ||
288 strcmp(method, "password") == 0)
289 authlog = logit;
290
291 if (authctxt->postponed)
292 authmsg = "Postponed";
293 else if (partial)
294 authmsg = "Partial";
295 else
296 authmsg = authenticated ? "Accepted" : "Failed";
297
298 authlog("%s %s%s%s for %s%.100s from %.200s port %d %s%s%s",
299 authmsg,
300 method,
301 submethod != NULL ? "/" : "", submethod == NULL ? "" : submethod,
302 authctxt->valid ? "" : "invalid user ",
303 authctxt->user,
304 get_remote_ipaddr(),
305 get_remote_port(),
306 compat20 ? "ssh2" : "ssh1",
307 authctxt->info != NULL ? ": " : "",
308 authctxt->info != NULL ? authctxt->info : "");
|
316 free(authctxt->info);
317 authctxt->info = NULL;
318
319#ifdef CUSTOM_FAILED_LOGIN
320 if (authenticated == 0 && !authctxt->postponed &&
321 (strcmp(method, "password") == 0 ||
322 strncmp(method, "keyboard-interactive", 20) == 0 ||
323 strcmp(method, "challenge-response") == 0))
324 record_failed_login(authctxt->user,
325 get_canonical_hostname(options.use_dns), "ssh");
326# ifdef WITH_AIXAUTHENTICATE
327 if (authenticated)
328 sys_auth_record_login(authctxt->user,
329 get_canonical_hostname(options.use_dns), "ssh", &loginmsg);
330# endif
331#endif
332#ifdef SSH_AUDIT_EVENTS
333 if (authenticated == 0 && !authctxt->postponed)
334 audit_event(audit_classify_auth(method));
335#endif
336}
337
338
339void
340auth_maxtries_exceeded(Authctxt *authctxt)
341{
342 error("maximum authentication attempts exceeded for "
343 "%s%.100s from %.200s port %d %s",
344 authctxt->valid ? "" : "invalid user ",
345 authctxt->user,
346 get_remote_ipaddr(),
347 get_remote_port(),
348 compat20 ? "ssh2" : "ssh1");
349 packet_disconnect("Too many authentication failures");
350 /* NOTREACHED */
351}
352
353/*
354 * Check whether root logins are disallowed.
355 */
356int
357auth_root_allowed(const char *method)
358{
359 switch (options.permit_root_login) {
360 case PERMIT_YES:
361 return 1;
362 case PERMIT_NO_PASSWD:
363 if (strcmp(method, "publickey") == 0 ||
364 strcmp(method, "hostbased") == 0 ||
365 strcmp(method, "gssapi-with-mic") == 0)
366 return 1;
367 break;
368 case PERMIT_FORCED_ONLY:
369 if (forced_command) {
370 logit("Root login accepted for forced command.");
371 return 1;
372 }
373 break;
374 }
375 logit("ROOT LOGIN REFUSED FROM %.200s", get_remote_ipaddr());
376 return 0;
377}
378
379
380/*
381 * Given a template and a passwd structure, build a filename
382 * by substituting % tokenised options. Currently, %% becomes '%',
383 * %h becomes the home directory and %u the username.
384 *
385 * This returns a buffer allocated by xmalloc.
386 */
387char *
388expand_authorized_keys(const char *filename, struct passwd *pw)
389{
390 char *file, ret[PATH_MAX];
391 int i;
392
393 file = percent_expand(filename, "h", pw->pw_dir,
394 "u", pw->pw_name, (char *)NULL);
395
396 /*
397 * Ensure that filename starts anchored. If not, be backward
398 * compatible and prepend the '%h/'
399 */
400 if (*file == '/')
401 return (file);
402
403 i = snprintf(ret, sizeof(ret), "%s/%s", pw->pw_dir, file);
404 if (i < 0 || (size_t)i >= sizeof(ret))
405 fatal("expand_authorized_keys: path too long");
406 free(file);
407 return (xstrdup(ret));
408}
409
410char *
411authorized_principals_file(struct passwd *pw)
412{
413 if (options.authorized_principals_file == NULL)
414 return NULL;
415 return expand_authorized_keys(options.authorized_principals_file, pw);
416}
417
418/* return ok if key exists in sysfile or userfile */
419HostStatus
420check_key_in_hostfiles(struct passwd *pw, Key *key, const char *host,
421 const char *sysfile, const char *userfile)
422{
423 char *user_hostfile;
424 struct stat st;
425 HostStatus host_status;
426 struct hostkeys *hostkeys;
427 const struct hostkey_entry *found;
428
429 hostkeys = init_hostkeys();
430 load_hostkeys(hostkeys, host, sysfile);
431 if (userfile != NULL) {
432 user_hostfile = tilde_expand_filename(userfile, pw->pw_uid);
433 if (options.strict_modes &&
434 (stat(user_hostfile, &st) == 0) &&
435 ((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
436 (st.st_mode & 022) != 0)) {
437 logit("Authentication refused for %.100s: "
438 "bad owner or modes for %.200s",
439 pw->pw_name, user_hostfile);
440 auth_debug_add("Ignored %.200s: bad ownership or modes",
441 user_hostfile);
442 } else {
443 temporarily_use_uid(pw);
444 load_hostkeys(hostkeys, host, user_hostfile);
445 restore_uid();
446 }
447 free(user_hostfile);
448 }
449 host_status = check_key_in_hostkeys(hostkeys, key, &found);
450 if (host_status == HOST_REVOKED)
451 error("WARNING: revoked key for %s attempted authentication",
452 found->host);
453 else if (host_status == HOST_OK)
454 debug("%s: key for %s found at %s:%ld", __func__,
455 found->host, found->file, found->line);
456 else
457 debug("%s: key for host %s not found", __func__, host);
458
459 free_hostkeys(hostkeys);
460
461 return host_status;
462}
463
464/*
465 * Check a given path for security. This is defined as all components
466 * of the path to the file must be owned by either the owner of
467 * of the file or root and no directories must be group or world writable.
468 *
469 * XXX Should any specific check be done for sym links ?
470 *
471 * Takes a file name, its stat information (preferably from fstat() to
472 * avoid races), the uid of the expected owner, their home directory and an
473 * error buffer plus max size as arguments.
474 *
475 * Returns 0 on success and -1 on failure
476 */
477int
478auth_secure_path(const char *name, struct stat *stp, const char *pw_dir,
479 uid_t uid, char *err, size_t errlen)
480{
481 char buf[PATH_MAX], homedir[PATH_MAX];
482 char *cp;
483 int comparehome = 0;
484 struct stat st;
485
486 if (realpath(name, buf) == NULL) {
487 snprintf(err, errlen, "realpath %s failed: %s", name,
488 strerror(errno));
489 return -1;
490 }
491 if (pw_dir != NULL && realpath(pw_dir, homedir) != NULL)
492 comparehome = 1;
493
494 if (!S_ISREG(stp->st_mode)) {
495 snprintf(err, errlen, "%s is not a regular file", buf);
496 return -1;
497 }
498 if ((!platform_sys_dir_uid(stp->st_uid) && stp->st_uid != uid) ||
499 (stp->st_mode & 022) != 0) {
500 snprintf(err, errlen, "bad ownership or modes for file %s",
501 buf);
502 return -1;
503 }
504
505 /* for each component of the canonical path, walking upwards */
506 for (;;) {
507 if ((cp = dirname(buf)) == NULL) {
508 snprintf(err, errlen, "dirname() failed");
509 return -1;
510 }
511 strlcpy(buf, cp, sizeof(buf));
512
513 if (stat(buf, &st) < 0 ||
514 (!platform_sys_dir_uid(st.st_uid) && st.st_uid != uid) ||
515 (st.st_mode & 022) != 0) {
516 snprintf(err, errlen,
517 "bad ownership or modes for directory %s", buf);
518 return -1;
519 }
520
521 /* If are past the homedir then we can stop */
522 if (comparehome && strcmp(homedir, buf) == 0)
523 break;
524
525 /*
526 * dirname should always complete with a "/" path,
527 * but we can be paranoid and check for "." too
528 */
529 if ((strcmp("/", buf) == 0) || (strcmp(".", buf) == 0))
530 break;
531 }
532 return 0;
533}
534
535/*
536 * Version of secure_path() that accepts an open file descriptor to
537 * avoid races.
538 *
539 * Returns 0 on success and -1 on failure
540 */
541static int
542secure_filename(FILE *f, const char *file, struct passwd *pw,
543 char *err, size_t errlen)
544{
545 struct stat st;
546
547 /* check the open file to avoid races */
548 if (fstat(fileno(f), &st) < 0) {
549 snprintf(err, errlen, "cannot stat file %s: %s",
550 file, strerror(errno));
551 return -1;
552 }
553 return auth_secure_path(file, &st, pw->pw_dir, pw->pw_uid, err, errlen);
554}
555
556static FILE *
557auth_openfile(const char *file, struct passwd *pw, int strict_modes,
558 int log_missing, char *file_type)
559{
560 char line[1024];
561 struct stat st;
562 int fd;
563 FILE *f;
564
565 if ((fd = open(file, O_RDONLY|O_NONBLOCK)) == -1) {
566 if (log_missing || errno != ENOENT)
567 debug("Could not open %s '%s': %s", file_type, file,
568 strerror(errno));
569 return NULL;
570 }
571
572 if (fstat(fd, &st) < 0) {
573 close(fd);
574 return NULL;
575 }
576 if (!S_ISREG(st.st_mode)) {
577 logit("User %s %s %s is not a regular file",
578 pw->pw_name, file_type, file);
579 close(fd);
580 return NULL;
581 }
582 unset_nonblock(fd);
583 if ((f = fdopen(fd, "r")) == NULL) {
584 close(fd);
585 return NULL;
586 }
587 if (strict_modes &&
588 secure_filename(f, file, pw, line, sizeof(line)) != 0) {
589 fclose(f);
590 logit("Authentication refused: %s", line);
591 auth_debug_add("Ignored %s: %s", file_type, line);
592 return NULL;
593 }
594
595 return f;
596}
597
598
599FILE *
600auth_openkeyfile(const char *file, struct passwd *pw, int strict_modes)
601{
602 return auth_openfile(file, pw, strict_modes, 1, "authorized keys");
603}
604
605FILE *
606auth_openprincipals(const char *file, struct passwd *pw, int strict_modes)
607{
608 return auth_openfile(file, pw, strict_modes, 0,
609 "authorized principals");
610}
611
612struct passwd *
613getpwnamallow(const char *user)
614{
615#ifdef HAVE_LOGIN_CAP
616 extern login_cap_t *lc;
617#ifdef BSD_AUTH
618 auth_session_t *as;
619#endif
620#endif
621 struct passwd *pw;
622 struct connection_info *ci = get_connection_info(1, options.use_dns);
623
624 ci->user = user;
625 parse_server_match_config(&options, ci);
626
627#if defined(_AIX) && defined(HAVE_SETAUTHDB)
628 aix_setauthdb(user);
629#endif
630
631 pw = getpwnam(user);
632
633#if defined(_AIX) && defined(HAVE_SETAUTHDB)
634 aix_restoreauthdb();
635#endif
636#ifdef HAVE_CYGWIN
637 /*
638 * Windows usernames are case-insensitive. To avoid later problems
639 * when trying to match the username, the user is only allowed to
640 * login if the username is given in the same case as stored in the
641 * user database.
642 */
643 if (pw != NULL && strcmp(user, pw->pw_name) != 0) {
644 logit("Login name %.100s does not match stored username %.100s",
645 user, pw->pw_name);
646 pw = NULL;
647 }
648#endif
649 if (pw == NULL) {
| 309 free(authctxt->info);
310 authctxt->info = NULL;
311
312#ifdef CUSTOM_FAILED_LOGIN
313 if (authenticated == 0 && !authctxt->postponed &&
314 (strcmp(method, "password") == 0 ||
315 strncmp(method, "keyboard-interactive", 20) == 0 ||
316 strcmp(method, "challenge-response") == 0))
317 record_failed_login(authctxt->user,
318 get_canonical_hostname(options.use_dns), "ssh");
319# ifdef WITH_AIXAUTHENTICATE
320 if (authenticated)
321 sys_auth_record_login(authctxt->user,
322 get_canonical_hostname(options.use_dns), "ssh", &loginmsg);
323# endif
324#endif
325#ifdef SSH_AUDIT_EVENTS
326 if (authenticated == 0 && !authctxt->postponed)
327 audit_event(audit_classify_auth(method));
328#endif
329}
330
331
332void
333auth_maxtries_exceeded(Authctxt *authctxt)
334{
335 error("maximum authentication attempts exceeded for "
336 "%s%.100s from %.200s port %d %s",
337 authctxt->valid ? "" : "invalid user ",
338 authctxt->user,
339 get_remote_ipaddr(),
340 get_remote_port(),
341 compat20 ? "ssh2" : "ssh1");
342 packet_disconnect("Too many authentication failures");
343 /* NOTREACHED */
344}
345
346/*
347 * Check whether root logins are disallowed.
348 */
349int
350auth_root_allowed(const char *method)
351{
352 switch (options.permit_root_login) {
353 case PERMIT_YES:
354 return 1;
355 case PERMIT_NO_PASSWD:
356 if (strcmp(method, "publickey") == 0 ||
357 strcmp(method, "hostbased") == 0 ||
358 strcmp(method, "gssapi-with-mic") == 0)
359 return 1;
360 break;
361 case PERMIT_FORCED_ONLY:
362 if (forced_command) {
363 logit("Root login accepted for forced command.");
364 return 1;
365 }
366 break;
367 }
368 logit("ROOT LOGIN REFUSED FROM %.200s", get_remote_ipaddr());
369 return 0;
370}
371
372
373/*
374 * Given a template and a passwd structure, build a filename
375 * by substituting % tokenised options. Currently, %% becomes '%',
376 * %h becomes the home directory and %u the username.
377 *
378 * This returns a buffer allocated by xmalloc.
379 */
380char *
381expand_authorized_keys(const char *filename, struct passwd *pw)
382{
383 char *file, ret[PATH_MAX];
384 int i;
385
386 file = percent_expand(filename, "h", pw->pw_dir,
387 "u", pw->pw_name, (char *)NULL);
388
389 /*
390 * Ensure that filename starts anchored. If not, be backward
391 * compatible and prepend the '%h/'
392 */
393 if (*file == '/')
394 return (file);
395
396 i = snprintf(ret, sizeof(ret), "%s/%s", pw->pw_dir, file);
397 if (i < 0 || (size_t)i >= sizeof(ret))
398 fatal("expand_authorized_keys: path too long");
399 free(file);
400 return (xstrdup(ret));
401}
402
403char *
404authorized_principals_file(struct passwd *pw)
405{
406 if (options.authorized_principals_file == NULL)
407 return NULL;
408 return expand_authorized_keys(options.authorized_principals_file, pw);
409}
410
411/* return ok if key exists in sysfile or userfile */
412HostStatus
413check_key_in_hostfiles(struct passwd *pw, Key *key, const char *host,
414 const char *sysfile, const char *userfile)
415{
416 char *user_hostfile;
417 struct stat st;
418 HostStatus host_status;
419 struct hostkeys *hostkeys;
420 const struct hostkey_entry *found;
421
422 hostkeys = init_hostkeys();
423 load_hostkeys(hostkeys, host, sysfile);
424 if (userfile != NULL) {
425 user_hostfile = tilde_expand_filename(userfile, pw->pw_uid);
426 if (options.strict_modes &&
427 (stat(user_hostfile, &st) == 0) &&
428 ((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
429 (st.st_mode & 022) != 0)) {
430 logit("Authentication refused for %.100s: "
431 "bad owner or modes for %.200s",
432 pw->pw_name, user_hostfile);
433 auth_debug_add("Ignored %.200s: bad ownership or modes",
434 user_hostfile);
435 } else {
436 temporarily_use_uid(pw);
437 load_hostkeys(hostkeys, host, user_hostfile);
438 restore_uid();
439 }
440 free(user_hostfile);
441 }
442 host_status = check_key_in_hostkeys(hostkeys, key, &found);
443 if (host_status == HOST_REVOKED)
444 error("WARNING: revoked key for %s attempted authentication",
445 found->host);
446 else if (host_status == HOST_OK)
447 debug("%s: key for %s found at %s:%ld", __func__,
448 found->host, found->file, found->line);
449 else
450 debug("%s: key for host %s not found", __func__, host);
451
452 free_hostkeys(hostkeys);
453
454 return host_status;
455}
456
457/*
458 * Check a given path for security. This is defined as all components
459 * of the path to the file must be owned by either the owner of
460 * of the file or root and no directories must be group or world writable.
461 *
462 * XXX Should any specific check be done for sym links ?
463 *
464 * Takes a file name, its stat information (preferably from fstat() to
465 * avoid races), the uid of the expected owner, their home directory and an
466 * error buffer plus max size as arguments.
467 *
468 * Returns 0 on success and -1 on failure
469 */
470int
471auth_secure_path(const char *name, struct stat *stp, const char *pw_dir,
472 uid_t uid, char *err, size_t errlen)
473{
474 char buf[PATH_MAX], homedir[PATH_MAX];
475 char *cp;
476 int comparehome = 0;
477 struct stat st;
478
479 if (realpath(name, buf) == NULL) {
480 snprintf(err, errlen, "realpath %s failed: %s", name,
481 strerror(errno));
482 return -1;
483 }
484 if (pw_dir != NULL && realpath(pw_dir, homedir) != NULL)
485 comparehome = 1;
486
487 if (!S_ISREG(stp->st_mode)) {
488 snprintf(err, errlen, "%s is not a regular file", buf);
489 return -1;
490 }
491 if ((!platform_sys_dir_uid(stp->st_uid) && stp->st_uid != uid) ||
492 (stp->st_mode & 022) != 0) {
493 snprintf(err, errlen, "bad ownership or modes for file %s",
494 buf);
495 return -1;
496 }
497
498 /* for each component of the canonical path, walking upwards */
499 for (;;) {
500 if ((cp = dirname(buf)) == NULL) {
501 snprintf(err, errlen, "dirname() failed");
502 return -1;
503 }
504 strlcpy(buf, cp, sizeof(buf));
505
506 if (stat(buf, &st) < 0 ||
507 (!platform_sys_dir_uid(st.st_uid) && st.st_uid != uid) ||
508 (st.st_mode & 022) != 0) {
509 snprintf(err, errlen,
510 "bad ownership or modes for directory %s", buf);
511 return -1;
512 }
513
514 /* If are past the homedir then we can stop */
515 if (comparehome && strcmp(homedir, buf) == 0)
516 break;
517
518 /*
519 * dirname should always complete with a "/" path,
520 * but we can be paranoid and check for "." too
521 */
522 if ((strcmp("/", buf) == 0) || (strcmp(".", buf) == 0))
523 break;
524 }
525 return 0;
526}
527
528/*
529 * Version of secure_path() that accepts an open file descriptor to
530 * avoid races.
531 *
532 * Returns 0 on success and -1 on failure
533 */
534static int
535secure_filename(FILE *f, const char *file, struct passwd *pw,
536 char *err, size_t errlen)
537{
538 struct stat st;
539
540 /* check the open file to avoid races */
541 if (fstat(fileno(f), &st) < 0) {
542 snprintf(err, errlen, "cannot stat file %s: %s",
543 file, strerror(errno));
544 return -1;
545 }
546 return auth_secure_path(file, &st, pw->pw_dir, pw->pw_uid, err, errlen);
547}
548
549static FILE *
550auth_openfile(const char *file, struct passwd *pw, int strict_modes,
551 int log_missing, char *file_type)
552{
553 char line[1024];
554 struct stat st;
555 int fd;
556 FILE *f;
557
558 if ((fd = open(file, O_RDONLY|O_NONBLOCK)) == -1) {
559 if (log_missing || errno != ENOENT)
560 debug("Could not open %s '%s': %s", file_type, file,
561 strerror(errno));
562 return NULL;
563 }
564
565 if (fstat(fd, &st) < 0) {
566 close(fd);
567 return NULL;
568 }
569 if (!S_ISREG(st.st_mode)) {
570 logit("User %s %s %s is not a regular file",
571 pw->pw_name, file_type, file);
572 close(fd);
573 return NULL;
574 }
575 unset_nonblock(fd);
576 if ((f = fdopen(fd, "r")) == NULL) {
577 close(fd);
578 return NULL;
579 }
580 if (strict_modes &&
581 secure_filename(f, file, pw, line, sizeof(line)) != 0) {
582 fclose(f);
583 logit("Authentication refused: %s", line);
584 auth_debug_add("Ignored %s: %s", file_type, line);
585 return NULL;
586 }
587
588 return f;
589}
590
591
592FILE *
593auth_openkeyfile(const char *file, struct passwd *pw, int strict_modes)
594{
595 return auth_openfile(file, pw, strict_modes, 1, "authorized keys");
596}
597
598FILE *
599auth_openprincipals(const char *file, struct passwd *pw, int strict_modes)
600{
601 return auth_openfile(file, pw, strict_modes, 0,
602 "authorized principals");
603}
604
605struct passwd *
606getpwnamallow(const char *user)
607{
608#ifdef HAVE_LOGIN_CAP
609 extern login_cap_t *lc;
610#ifdef BSD_AUTH
611 auth_session_t *as;
612#endif
613#endif
614 struct passwd *pw;
615 struct connection_info *ci = get_connection_info(1, options.use_dns);
616
617 ci->user = user;
618 parse_server_match_config(&options, ci);
619
620#if defined(_AIX) && defined(HAVE_SETAUTHDB)
621 aix_setauthdb(user);
622#endif
623
624 pw = getpwnam(user);
625
626#if defined(_AIX) && defined(HAVE_SETAUTHDB)
627 aix_restoreauthdb();
628#endif
629#ifdef HAVE_CYGWIN
630 /*
631 * Windows usernames are case-insensitive. To avoid later problems
632 * when trying to match the username, the user is only allowed to
633 * login if the username is given in the same case as stored in the
634 * user database.
635 */
636 if (pw != NULL && strcmp(user, pw->pw_name) != 0) {
637 logit("Login name %.100s does not match stored username %.100s",
638 user, pw->pw_name);
639 pw = NULL;
640 }
641#endif
642 if (pw == NULL) {
|
653 logit("Invalid user %.100s from %.100s",
654 user, get_remote_ipaddr());
655#ifdef CUSTOM_FAILED_LOGIN
656 record_failed_login(user,
657 get_canonical_hostname(options.use_dns), "ssh");
658#endif
659#ifdef SSH_AUDIT_EVENTS
660 audit_event(SSH_INVALID_USER);
661#endif /* SSH_AUDIT_EVENTS */
662 return (NULL);
663 }
664 if (!allowed_user(pw))
665 return (NULL);
666#ifdef HAVE_LOGIN_CAP
667 if ((lc = login_getpwclass(pw)) == NULL) {
668 debug("unable to get login class: %s", user);
669 return (NULL);
670 }
671#ifdef BSD_AUTH
672 if ((as = auth_open()) == NULL || auth_setpwd(as, pw) != 0 ||
673 auth_approval(as, lc, pw->pw_name, "ssh") <= 0) {
674 debug("Approval failure for %s", user);
675 pw = NULL;
676 }
677 if (as != NULL)
678 auth_close(as);
679#endif
680#endif
681 if (pw != NULL)
682 return (pwcopy(pw));
683 return (NULL);
684}
685
686/* Returns 1 if key is revoked by revoked_keys_file, 0 otherwise */
687int
688auth_key_is_revoked(Key *key)
689{
690 char *fp = NULL;
691 int r;
692
693 if (options.revoked_keys_file == NULL)
694 return 0;
695 if ((fp = sshkey_fingerprint(key, options.fingerprint_hash,
696 SSH_FP_DEFAULT)) == NULL) {
697 r = SSH_ERR_ALLOC_FAIL;
698 error("%s: fingerprint key: %s", __func__, ssh_err(r));
699 goto out;
700 }
701
702 r = sshkey_check_revoked(key, options.revoked_keys_file);
703 switch (r) {
704 case 0:
705 break; /* not revoked */
706 case SSH_ERR_KEY_REVOKED:
707 error("Authentication key %s %s revoked by file %s",
708 sshkey_type(key), fp, options.revoked_keys_file);
709 goto out;
710 default:
711 error("Error checking authentication key %s %s in "
712 "revoked keys file %s: %s", sshkey_type(key), fp,
713 options.revoked_keys_file, ssh_err(r));
714 goto out;
715 }
716
717 /* Success */
718 r = 0;
719
720 out:
721 free(fp);
722 return r == 0 ? 0 : 1;
723}
724
725void
726auth_debug_add(const char *fmt,...)
727{
728 char buf[1024];
729 va_list args;
730
731 if (!auth_debug_init)
732 return;
733
734 va_start(args, fmt);
735 vsnprintf(buf, sizeof(buf), fmt, args);
736 va_end(args);
737 buffer_put_cstring(&auth_debug, buf);
738}
739
740void
741auth_debug_send(void)
742{
743 char *msg;
744
745 if (!auth_debug_init)
746 return;
747 while (buffer_len(&auth_debug)) {
748 msg = buffer_get_string(&auth_debug, NULL);
749 packet_send_debug("%s", msg);
750 free(msg);
751 }
752}
753
754void
755auth_debug_reset(void)
756{
757 if (auth_debug_init)
758 buffer_clear(&auth_debug);
759 else {
760 buffer_init(&auth_debug);
761 auth_debug_init = 1;
762 }
763}
764
765struct passwd *
766fakepw(void)
767{
768 static struct passwd fake;
769
770 memset(&fake, 0, sizeof(fake));
771 fake.pw_name = "NOUSER";
772 fake.pw_passwd =
773 "$2a$06$r3.juUaHZDlIbQaO2dS9FuYxL1W9M81R1Tc92PoSNmzvpEqLkLGrK";
774#ifdef HAVE_STRUCT_PASSWD_PW_GECOS
775 fake.pw_gecos = "NOUSER";
776#endif
777 fake.pw_uid = privsep_pw == NULL ? (uid_t)-1 : privsep_pw->pw_uid;
778 fake.pw_gid = privsep_pw == NULL ? (gid_t)-1 : privsep_pw->pw_gid;
779#ifdef HAVE_STRUCT_PASSWD_PW_CLASS
780 fake.pw_class = "";
781#endif
782 fake.pw_dir = "/nonexist";
783 fake.pw_shell = "/nonexist";
784
785 return (&fake);
786}
| 643 logit("Invalid user %.100s from %.100s",
644 user, get_remote_ipaddr());
645#ifdef CUSTOM_FAILED_LOGIN
646 record_failed_login(user,
647 get_canonical_hostname(options.use_dns), "ssh");
648#endif
649#ifdef SSH_AUDIT_EVENTS
650 audit_event(SSH_INVALID_USER);
651#endif /* SSH_AUDIT_EVENTS */
652 return (NULL);
653 }
654 if (!allowed_user(pw))
655 return (NULL);
656#ifdef HAVE_LOGIN_CAP
657 if ((lc = login_getpwclass(pw)) == NULL) {
658 debug("unable to get login class: %s", user);
659 return (NULL);
660 }
661#ifdef BSD_AUTH
662 if ((as = auth_open()) == NULL || auth_setpwd(as, pw) != 0 ||
663 auth_approval(as, lc, pw->pw_name, "ssh") <= 0) {
664 debug("Approval failure for %s", user);
665 pw = NULL;
666 }
667 if (as != NULL)
668 auth_close(as);
669#endif
670#endif
671 if (pw != NULL)
672 return (pwcopy(pw));
673 return (NULL);
674}
675
676/* Returns 1 if key is revoked by revoked_keys_file, 0 otherwise */
677int
678auth_key_is_revoked(Key *key)
679{
680 char *fp = NULL;
681 int r;
682
683 if (options.revoked_keys_file == NULL)
684 return 0;
685 if ((fp = sshkey_fingerprint(key, options.fingerprint_hash,
686 SSH_FP_DEFAULT)) == NULL) {
687 r = SSH_ERR_ALLOC_FAIL;
688 error("%s: fingerprint key: %s", __func__, ssh_err(r));
689 goto out;
690 }
691
692 r = sshkey_check_revoked(key, options.revoked_keys_file);
693 switch (r) {
694 case 0:
695 break; /* not revoked */
696 case SSH_ERR_KEY_REVOKED:
697 error("Authentication key %s %s revoked by file %s",
698 sshkey_type(key), fp, options.revoked_keys_file);
699 goto out;
700 default:
701 error("Error checking authentication key %s %s in "
702 "revoked keys file %s: %s", sshkey_type(key), fp,
703 options.revoked_keys_file, ssh_err(r));
704 goto out;
705 }
706
707 /* Success */
708 r = 0;
709
710 out:
711 free(fp);
712 return r == 0 ? 0 : 1;
713}
714
715void
716auth_debug_add(const char *fmt,...)
717{
718 char buf[1024];
719 va_list args;
720
721 if (!auth_debug_init)
722 return;
723
724 va_start(args, fmt);
725 vsnprintf(buf, sizeof(buf), fmt, args);
726 va_end(args);
727 buffer_put_cstring(&auth_debug, buf);
728}
729
730void
731auth_debug_send(void)
732{
733 char *msg;
734
735 if (!auth_debug_init)
736 return;
737 while (buffer_len(&auth_debug)) {
738 msg = buffer_get_string(&auth_debug, NULL);
739 packet_send_debug("%s", msg);
740 free(msg);
741 }
742}
743
744void
745auth_debug_reset(void)
746{
747 if (auth_debug_init)
748 buffer_clear(&auth_debug);
749 else {
750 buffer_init(&auth_debug);
751 auth_debug_init = 1;
752 }
753}
754
755struct passwd *
756fakepw(void)
757{
758 static struct passwd fake;
759
760 memset(&fake, 0, sizeof(fake));
761 fake.pw_name = "NOUSER";
762 fake.pw_passwd =
763 "$2a$06$r3.juUaHZDlIbQaO2dS9FuYxL1W9M81R1Tc92PoSNmzvpEqLkLGrK";
764#ifdef HAVE_STRUCT_PASSWD_PW_GECOS
765 fake.pw_gecos = "NOUSER";
766#endif
767 fake.pw_uid = privsep_pw == NULL ? (uid_t)-1 : privsep_pw->pw_uid;
768 fake.pw_gid = privsep_pw == NULL ? (gid_t)-1 : privsep_pw->pw_gid;
769#ifdef HAVE_STRUCT_PASSWD_PW_CLASS
770 fake.pw_class = "";
771#endif
772 fake.pw_dir = "/nonexist";
773 fake.pw_shell = "/nonexist";
774
775 return (&fake);
776}
|