Greg Hartman | bd77cf7 | 2015-02-25 13:21:06 -0800 | [diff] [blame] | 1 | /* $OpenBSD: auth.c,v 1.94 2011/05/23 03:33:38 djm Exp $ */ |
| 2 | /* |
| 3 | * Copyright (c) 2000 Markus Friedl. All rights reserved. |
| 4 | * |
| 5 | * Redistribution and use in source and binary forms, with or without |
| 6 | * modification, are permitted provided that the following conditions |
| 7 | * are met: |
| 8 | * 1. Redistributions of source code must retain the above copyright |
| 9 | * notice, this list of conditions and the following disclaimer. |
| 10 | * 2. Redistributions in binary form must reproduce the above copyright |
| 11 | * notice, this list of conditions and the following disclaimer in the |
| 12 | * documentation and/or other materials provided with the distribution. |
| 13 | * |
| 14 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| 15 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| 16 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| 17 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| 18 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| 19 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 20 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 21 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 22 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| 23 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 24 | */ |
| 25 | |
| 26 | #include "includes.h" |
| 27 | |
| 28 | #include <sys/types.h> |
| 29 | #include <sys/stat.h> |
| 30 | #include <sys/param.h> |
| 31 | |
| 32 | #include <netinet/in.h> |
| 33 | |
| 34 | #include <errno.h> |
| 35 | #include <fcntl.h> |
| 36 | #ifdef HAVE_PATHS_H |
| 37 | # include <paths.h> |
| 38 | #endif |
| 39 | #include <pwd.h> |
| 40 | #ifdef HAVE_LOGIN_H |
| 41 | #include <login.h> |
| 42 | #endif |
| 43 | #ifdef USE_SHADOW |
| 44 | #include <shadow.h> |
| 45 | #endif |
| 46 | #ifdef HAVE_LIBGEN_H |
| 47 | #include <libgen.h> |
| 48 | #endif |
| 49 | #include <stdarg.h> |
| 50 | #include <stdio.h> |
| 51 | #include <string.h> |
| 52 | #include <unistd.h> |
| 53 | |
| 54 | #include "xmalloc.h" |
| 55 | #include "match.h" |
| 56 | #include "groupaccess.h" |
| 57 | #include "log.h" |
| 58 | #include "buffer.h" |
| 59 | #include "servconf.h" |
| 60 | #include "key.h" |
| 61 | #include "hostfile.h" |
| 62 | #include "auth.h" |
| 63 | #include "auth-options.h" |
| 64 | #include "canohost.h" |
| 65 | #include "uidswap.h" |
| 66 | #include "misc.h" |
| 67 | #include "packet.h" |
| 68 | #include "loginrec.h" |
| 69 | #ifdef GSSAPI |
| 70 | #include "ssh-gss.h" |
| 71 | #endif |
| 72 | #include "authfile.h" |
| 73 | #include "monitor_wrap.h" |
| 74 | |
| 75 | /* import */ |
| 76 | extern ServerOptions options; |
| 77 | extern int use_privsep; |
| 78 | extern Buffer loginmsg; |
| 79 | extern struct passwd *privsep_pw; |
| 80 | |
| 81 | /* Debugging messages */ |
| 82 | Buffer auth_debug; |
| 83 | int auth_debug_init; |
| 84 | |
| 85 | /* |
| 86 | * Check if the user is allowed to log in via ssh. If user is listed |
| 87 | * in DenyUsers or one of user's groups is listed in DenyGroups, false |
| 88 | * will be returned. If AllowUsers isn't empty and user isn't listed |
| 89 | * there, or if AllowGroups isn't empty and one of user's groups isn't |
| 90 | * listed there, false will be returned. |
| 91 | * If the user's shell is not executable, false will be returned. |
| 92 | * Otherwise true is returned. |
| 93 | */ |
| 94 | int |
| 95 | allowed_user(struct passwd * pw) |
| 96 | { |
| 97 | struct stat st; |
| 98 | const char *hostname = NULL, *ipaddr = NULL, *passwd = NULL; |
| 99 | u_int i; |
| 100 | #ifdef USE_SHADOW |
| 101 | struct spwd *spw = NULL; |
| 102 | #endif |
| 103 | |
| 104 | /* Shouldn't be called if pw is NULL, but better safe than sorry... */ |
| 105 | if (!pw || !pw->pw_name) |
| 106 | return 0; |
| 107 | |
| 108 | #ifdef USE_SHADOW |
| 109 | if (!options.use_pam) |
| 110 | spw = getspnam(pw->pw_name); |
| 111 | #ifdef HAS_SHADOW_EXPIRE |
| 112 | if (!options.use_pam && spw != NULL && auth_shadow_acctexpired(spw)) |
| 113 | return 0; |
| 114 | #endif /* HAS_SHADOW_EXPIRE */ |
| 115 | #endif /* USE_SHADOW */ |
| 116 | |
| 117 | /* grab passwd field for locked account check */ |
| 118 | passwd = pw->pw_passwd; |
| 119 | #ifdef USE_SHADOW |
| 120 | if (spw != NULL) |
| 121 | #ifdef USE_LIBIAF |
| 122 | passwd = get_iaf_password(pw); |
| 123 | #else |
| 124 | passwd = spw->sp_pwdp; |
| 125 | #endif /* USE_LIBIAF */ |
| 126 | #endif |
| 127 | |
| 128 | /* check for locked account */ |
| 129 | if (!options.use_pam && passwd && *passwd) { |
| 130 | int locked = 0; |
| 131 | |
| 132 | #ifdef LOCKED_PASSWD_STRING |
| 133 | if (strcmp(passwd, LOCKED_PASSWD_STRING) == 0) |
| 134 | locked = 1; |
| 135 | #endif |
| 136 | #ifdef LOCKED_PASSWD_PREFIX |
| 137 | if (strncmp(passwd, LOCKED_PASSWD_PREFIX, |
| 138 | strlen(LOCKED_PASSWD_PREFIX)) == 0) |
| 139 | locked = 1; |
| 140 | #endif |
| 141 | #ifdef LOCKED_PASSWD_SUBSTR |
| 142 | if (strstr(passwd, LOCKED_PASSWD_SUBSTR)) |
| 143 | locked = 1; |
| 144 | #endif |
| 145 | #ifdef USE_LIBIAF |
| 146 | free((void *) passwd); |
| 147 | #endif /* USE_LIBIAF */ |
| 148 | if (locked) { |
| 149 | logit("User %.100s not allowed because account is locked", |
| 150 | pw->pw_name); |
| 151 | return 0; |
| 152 | } |
| 153 | } |
| 154 | |
| 155 | /* |
| 156 | * Deny if shell does not exist or is not executable unless we |
| 157 | * are chrooting. |
| 158 | */ |
| 159 | if (options.chroot_directory == NULL || |
| 160 | strcasecmp(options.chroot_directory, "none") == 0) { |
| 161 | char *shell = xstrdup((pw->pw_shell[0] == '\0') ? |
| 162 | _PATH_BSHELL : pw->pw_shell); /* empty = /bin/sh */ |
| 163 | |
| 164 | if (stat(shell, &st) != 0) { |
| 165 | logit("User %.100s not allowed because shell %.100s " |
| 166 | "does not exist", pw->pw_name, shell); |
| 167 | xfree(shell); |
| 168 | return 0; |
| 169 | } |
| 170 | if (S_ISREG(st.st_mode) == 0 || |
| 171 | (st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP)) == 0) { |
| 172 | logit("User %.100s not allowed because shell %.100s " |
| 173 | "is not executable", pw->pw_name, shell); |
| 174 | xfree(shell); |
| 175 | return 0; |
| 176 | } |
| 177 | xfree(shell); |
| 178 | } |
| 179 | |
| 180 | if (options.num_deny_users > 0 || options.num_allow_users > 0 || |
| 181 | options.num_deny_groups > 0 || options.num_allow_groups > 0) { |
| 182 | hostname = get_canonical_hostname(options.use_dns); |
| 183 | ipaddr = get_remote_ipaddr(); |
| 184 | } |
| 185 | |
| 186 | /* Return false if user is listed in DenyUsers */ |
| 187 | if (options.num_deny_users > 0) { |
| 188 | for (i = 0; i < options.num_deny_users; i++) |
| 189 | if (match_user(pw->pw_name, hostname, ipaddr, |
| 190 | options.deny_users[i])) { |
| 191 | logit("User %.100s from %.100s not allowed " |
| 192 | "because listed in DenyUsers", |
| 193 | pw->pw_name, hostname); |
| 194 | return 0; |
| 195 | } |
| 196 | } |
| 197 | /* Return false if AllowUsers isn't empty and user isn't listed there */ |
| 198 | if (options.num_allow_users > 0) { |
| 199 | for (i = 0; i < options.num_allow_users; i++) |
| 200 | if (match_user(pw->pw_name, hostname, ipaddr, |
| 201 | options.allow_users[i])) |
| 202 | break; |
| 203 | /* i < options.num_allow_users iff we break for loop */ |
| 204 | if (i >= options.num_allow_users) { |
| 205 | logit("User %.100s from %.100s not allowed because " |
| 206 | "not listed in AllowUsers", pw->pw_name, hostname); |
| 207 | return 0; |
| 208 | } |
| 209 | } |
| 210 | if (options.num_deny_groups > 0 || options.num_allow_groups > 0) { |
| 211 | /* Get the user's group access list (primary and supplementary) */ |
| 212 | if (ga_init(pw->pw_name, pw->pw_gid) == 0) { |
| 213 | logit("User %.100s from %.100s not allowed because " |
| 214 | "not in any group", pw->pw_name, hostname); |
| 215 | return 0; |
| 216 | } |
| 217 | |
| 218 | /* Return false if one of user's groups is listed in DenyGroups */ |
| 219 | if (options.num_deny_groups > 0) |
| 220 | if (ga_match(options.deny_groups, |
| 221 | options.num_deny_groups)) { |
| 222 | ga_free(); |
| 223 | logit("User %.100s from %.100s not allowed " |
| 224 | "because a group is listed in DenyGroups", |
| 225 | pw->pw_name, hostname); |
| 226 | return 0; |
| 227 | } |
| 228 | /* |
| 229 | * Return false if AllowGroups isn't empty and one of user's groups |
| 230 | * isn't listed there |
| 231 | */ |
| 232 | if (options.num_allow_groups > 0) |
| 233 | if (!ga_match(options.allow_groups, |
| 234 | options.num_allow_groups)) { |
| 235 | ga_free(); |
| 236 | logit("User %.100s from %.100s not allowed " |
| 237 | "because none of user's groups are listed " |
| 238 | "in AllowGroups", pw->pw_name, hostname); |
| 239 | return 0; |
| 240 | } |
| 241 | ga_free(); |
| 242 | } |
| 243 | |
| 244 | #ifdef CUSTOM_SYS_AUTH_ALLOWED_USER |
| 245 | if (!sys_auth_allowed_user(pw, &loginmsg)) |
| 246 | return 0; |
| 247 | #endif |
| 248 | |
| 249 | /* We found no reason not to let this user try to log on... */ |
| 250 | return 1; |
| 251 | } |
| 252 | |
| 253 | void |
| 254 | auth_log(Authctxt *authctxt, int authenticated, char *method, char *info) |
| 255 | { |
| 256 | void (*authlog) (const char *fmt,...) = verbose; |
| 257 | char *authmsg; |
| 258 | |
| 259 | if (use_privsep && !mm_is_monitor() && !authctxt->postponed) |
| 260 | return; |
| 261 | |
| 262 | /* Raise logging level */ |
| 263 | if (authenticated == 1 || |
| 264 | !authctxt->valid || |
| 265 | authctxt->failures >= options.max_authtries / 2 || |
| 266 | strcmp(method, "password") == 0) |
| 267 | authlog = logit; |
| 268 | |
| 269 | if (authctxt->postponed) |
| 270 | authmsg = "Postponed"; |
| 271 | else |
| 272 | authmsg = authenticated ? "Accepted" : "Failed"; |
| 273 | |
| 274 | authlog("%s %s for %s%.100s from %.200s port %d%s", |
| 275 | authmsg, |
| 276 | method, |
| 277 | authctxt->valid ? "" : "invalid user ", |
| 278 | authctxt->user, |
| 279 | get_remote_ipaddr(), |
| 280 | get_remote_port(), |
| 281 | info); |
| 282 | |
| 283 | #ifdef CUSTOM_FAILED_LOGIN |
| 284 | if (authenticated == 0 && !authctxt->postponed && |
| 285 | (strcmp(method, "password") == 0 || |
| 286 | strncmp(method, "keyboard-interactive", 20) == 0 || |
| 287 | strcmp(method, "challenge-response") == 0)) |
| 288 | record_failed_login(authctxt->user, |
| 289 | get_canonical_hostname(options.use_dns), "ssh"); |
| 290 | # ifdef WITH_AIXAUTHENTICATE |
| 291 | if (authenticated) |
| 292 | sys_auth_record_login(authctxt->user, |
| 293 | get_canonical_hostname(options.use_dns), "ssh", &loginmsg); |
| 294 | # endif |
| 295 | #endif |
| 296 | #ifdef SSH_AUDIT_EVENTS |
| 297 | if (authenticated == 0 && !authctxt->postponed) |
| 298 | audit_event(audit_classify_auth(method)); |
| 299 | #endif |
| 300 | } |
| 301 | |
| 302 | /* |
| 303 | * Check whether root logins are disallowed. |
| 304 | */ |
| 305 | int |
| 306 | auth_root_allowed(char *method) |
| 307 | { |
| 308 | switch (options.permit_root_login) { |
| 309 | case PERMIT_YES: |
| 310 | return 1; |
| 311 | case PERMIT_NO_PASSWD: |
| 312 | if (strcmp(method, "password") != 0) |
| 313 | return 1; |
| 314 | break; |
| 315 | case PERMIT_FORCED_ONLY: |
| 316 | if (forced_command) { |
| 317 | logit("Root login accepted for forced command."); |
| 318 | return 1; |
| 319 | } |
| 320 | break; |
| 321 | } |
| 322 | logit("ROOT LOGIN REFUSED FROM %.200s", get_remote_ipaddr()); |
| 323 | return 0; |
| 324 | } |
| 325 | |
| 326 | |
| 327 | /* |
| 328 | * Given a template and a passwd structure, build a filename |
| 329 | * by substituting % tokenised options. Currently, %% becomes '%', |
| 330 | * %h becomes the home directory and %u the username. |
| 331 | * |
| 332 | * This returns a buffer allocated by xmalloc. |
| 333 | */ |
| 334 | char * |
| 335 | expand_authorized_keys(const char *filename, struct passwd *pw) |
| 336 | { |
| 337 | char *file, ret[MAXPATHLEN]; |
| 338 | int i; |
| 339 | |
| 340 | file = percent_expand(filename, "h", pw->pw_dir, |
| 341 | "u", pw->pw_name, (char *)NULL); |
| 342 | |
| 343 | /* |
| 344 | * Ensure that filename starts anchored. If not, be backward |
| 345 | * compatible and prepend the '%h/' |
| 346 | */ |
| 347 | if (*file == '/') |
| 348 | return (file); |
| 349 | |
| 350 | i = snprintf(ret, sizeof(ret), "%s/%s", pw->pw_dir, file); |
| 351 | if (i < 0 || (size_t)i >= sizeof(ret)) |
| 352 | fatal("expand_authorized_keys: path too long"); |
| 353 | xfree(file); |
| 354 | return (xstrdup(ret)); |
| 355 | } |
| 356 | |
| 357 | char * |
| 358 | authorized_principals_file(struct passwd *pw) |
| 359 | { |
| 360 | if (options.authorized_principals_file == NULL) |
| 361 | return NULL; |
| 362 | return expand_authorized_keys(options.authorized_principals_file, pw); |
| 363 | } |
| 364 | |
| 365 | /* return ok if key exists in sysfile or userfile */ |
| 366 | HostStatus |
| 367 | check_key_in_hostfiles(struct passwd *pw, Key *key, const char *host, |
| 368 | const char *sysfile, const char *userfile) |
| 369 | { |
| 370 | char *user_hostfile; |
| 371 | struct stat st; |
| 372 | HostStatus host_status; |
| 373 | struct hostkeys *hostkeys; |
| 374 | const struct hostkey_entry *found; |
| 375 | |
| 376 | hostkeys = init_hostkeys(); |
| 377 | load_hostkeys(hostkeys, host, sysfile); |
| 378 | if (userfile != NULL) { |
| 379 | user_hostfile = tilde_expand_filename(userfile, pw->pw_uid); |
| 380 | if (options.strict_modes && |
| 381 | (stat(user_hostfile, &st) == 0) && |
| 382 | ((st.st_uid != 0 && st.st_uid != pw->pw_uid) || |
| 383 | (st.st_mode & 022) != 0)) { |
| 384 | logit("Authentication refused for %.100s: " |
| 385 | "bad owner or modes for %.200s", |
| 386 | pw->pw_name, user_hostfile); |
| 387 | auth_debug_add("Ignored %.200s: bad ownership or modes", |
| 388 | user_hostfile); |
| 389 | } else { |
| 390 | temporarily_use_uid(pw); |
| 391 | load_hostkeys(hostkeys, host, user_hostfile); |
| 392 | restore_uid(); |
| 393 | } |
| 394 | xfree(user_hostfile); |
| 395 | } |
| 396 | host_status = check_key_in_hostkeys(hostkeys, key, &found); |
| 397 | if (host_status == HOST_REVOKED) |
| 398 | error("WARNING: revoked key for %s attempted authentication", |
| 399 | found->host); |
| 400 | else if (host_status == HOST_OK) |
| 401 | debug("%s: key for %s found at %s:%ld", __func__, |
| 402 | found->host, found->file, found->line); |
| 403 | else |
| 404 | debug("%s: key for host %s not found", __func__, host); |
| 405 | |
| 406 | free_hostkeys(hostkeys); |
| 407 | |
| 408 | return host_status; |
| 409 | } |
| 410 | |
| 411 | |
| 412 | /* |
| 413 | * Check a given file for security. This is defined as all components |
| 414 | * of the path to the file must be owned by either the owner of |
| 415 | * of the file or root and no directories must be group or world writable. |
| 416 | * |
| 417 | * XXX Should any specific check be done for sym links ? |
| 418 | * |
| 419 | * Takes an open file descriptor, the file name, a uid and and |
| 420 | * error buffer plus max size as arguments. |
| 421 | * |
| 422 | * Returns 0 on success and -1 on failure |
| 423 | */ |
| 424 | static int |
| 425 | secure_filename(FILE *f, const char *file, struct passwd *pw, |
| 426 | char *err, size_t errlen) |
| 427 | { |
| 428 | uid_t uid = pw->pw_uid; |
| 429 | char buf[MAXPATHLEN], homedir[MAXPATHLEN]; |
| 430 | char *cp; |
| 431 | int comparehome = 0; |
| 432 | struct stat st; |
| 433 | |
| 434 | if (realpath(file, buf) == NULL) { |
| 435 | snprintf(err, errlen, "realpath %s failed: %s", file, |
| 436 | strerror(errno)); |
| 437 | return -1; |
| 438 | } |
| 439 | if (realpath(pw->pw_dir, homedir) != NULL) |
| 440 | comparehome = 1; |
| 441 | |
| 442 | /* check the open file to avoid races */ |
| 443 | if (fstat(fileno(f), &st) < 0 || |
| 444 | (st.st_uid != 0 && st.st_uid != uid) || |
| 445 | (st.st_mode & 022) != 0) { |
| 446 | #ifdef ANDROID |
| 447 | /* needed to allow root login on android */ |
| 448 | if (getuid() != 0) |
| 449 | #endif |
| 450 | { |
| 451 | snprintf(err, errlen, "bad ownership or modes for file %s", |
| 452 | buf); |
| 453 | return -1; |
| 454 | } |
| 455 | } |
| 456 | |
| 457 | /* for each component of the canonical path, walking upwards */ |
| 458 | for (;;) { |
| 459 | if ((cp = dirname(buf)) == NULL) { |
| 460 | snprintf(err, errlen, "dirname() failed"); |
| 461 | return -1; |
| 462 | } |
| 463 | strlcpy(buf, cp, sizeof(buf)); |
| 464 | |
| 465 | #ifndef ANDROID |
| 466 | /* /data is owned by system user, which causes this check to fail */ |
| 467 | if (stat(buf, &st) < 0 || |
| 468 | (st.st_uid != 0 && st.st_uid != uid) || |
| 469 | (st.st_mode & 022) != 0) { |
| 470 | snprintf(err, errlen, |
| 471 | "bad ownership or modes for directory %s", buf); |
| 472 | return -1; |
| 473 | } |
| 474 | #endif |
| 475 | /* If are past the homedir then we can stop */ |
| 476 | if (comparehome && strcmp(homedir, buf) == 0) |
| 477 | break; |
| 478 | |
| 479 | /* |
| 480 | * dirname should always complete with a "/" path, |
| 481 | * but we can be paranoid and check for "." too |
| 482 | */ |
| 483 | if ((strcmp("/", buf) == 0) || (strcmp(".", buf) == 0)) |
| 484 | break; |
| 485 | } |
| 486 | return 0; |
| 487 | } |
| 488 | |
| 489 | static FILE * |
| 490 | auth_openfile(const char *file, struct passwd *pw, int strict_modes, |
| 491 | int log_missing, char *file_type) |
| 492 | { |
| 493 | char line[1024]; |
| 494 | struct stat st; |
| 495 | int fd; |
| 496 | FILE *f; |
| 497 | |
| 498 | if ((fd = open(file, O_RDONLY|O_NONBLOCK)) == -1) { |
| 499 | if (log_missing || errno != ENOENT) |
| 500 | debug("Could not open %s '%s': %s", file_type, file, |
| 501 | strerror(errno)); |
| 502 | return NULL; |
| 503 | } |
| 504 | |
| 505 | if (fstat(fd, &st) < 0) { |
| 506 | close(fd); |
| 507 | return NULL; |
| 508 | } |
| 509 | if (!S_ISREG(st.st_mode)) { |
| 510 | logit("User %s %s %s is not a regular file", |
| 511 | pw->pw_name, file_type, file); |
| 512 | close(fd); |
| 513 | return NULL; |
| 514 | } |
| 515 | unset_nonblock(fd); |
| 516 | if ((f = fdopen(fd, "r")) == NULL) { |
| 517 | close(fd); |
| 518 | return NULL; |
| 519 | } |
| 520 | if (strict_modes && |
| 521 | secure_filename(f, file, pw, line, sizeof(line)) != 0) { |
| 522 | fclose(f); |
| 523 | logit("Authentication refused: %s", line); |
| 524 | auth_debug_add("Ignored %s: %s", file_type, line); |
| 525 | return NULL; |
| 526 | } |
| 527 | |
| 528 | return f; |
| 529 | } |
| 530 | |
| 531 | |
| 532 | FILE * |
| 533 | auth_openkeyfile(const char *file, struct passwd *pw, int strict_modes) |
| 534 | { |
| 535 | return auth_openfile(file, pw, strict_modes, 1, "authorized keys"); |
| 536 | } |
| 537 | |
| 538 | FILE * |
| 539 | auth_openprincipals(const char *file, struct passwd *pw, int strict_modes) |
| 540 | { |
| 541 | return auth_openfile(file, pw, strict_modes, 0, |
| 542 | "authorized principals"); |
| 543 | } |
| 544 | |
| 545 | struct passwd * |
| 546 | getpwnamallow(const char *user) |
| 547 | { |
| 548 | #ifdef HAVE_LOGIN_CAP |
| 549 | extern login_cap_t *lc; |
| 550 | #ifdef BSD_AUTH |
| 551 | auth_session_t *as; |
| 552 | #endif |
| 553 | #endif |
| 554 | struct passwd *pw; |
| 555 | |
| 556 | parse_server_match_config(&options, user, |
| 557 | get_canonical_hostname(options.use_dns), get_remote_ipaddr()); |
| 558 | |
| 559 | #if defined(_AIX) && defined(HAVE_SETAUTHDB) |
| 560 | aix_setauthdb(user); |
| 561 | #endif |
| 562 | |
| 563 | pw = getpwnam(user); |
| 564 | |
| 565 | #if defined(_AIX) && defined(HAVE_SETAUTHDB) |
| 566 | aix_restoreauthdb(); |
| 567 | #endif |
| 568 | #ifdef HAVE_CYGWIN |
| 569 | /* |
| 570 | * Windows usernames are case-insensitive. To avoid later problems |
| 571 | * when trying to match the username, the user is only allowed to |
| 572 | * login if the username is given in the same case as stored in the |
| 573 | * user database. |
| 574 | */ |
| 575 | if (pw != NULL && strcmp(user, pw->pw_name) != 0) { |
| 576 | logit("Login name %.100s does not match stored username %.100s", |
| 577 | user, pw->pw_name); |
| 578 | pw = NULL; |
| 579 | } |
| 580 | #endif |
| 581 | if (pw == NULL) { |
| 582 | logit("Invalid user %.100s from %.100s", |
| 583 | user, get_remote_ipaddr()); |
| 584 | #ifdef CUSTOM_FAILED_LOGIN |
| 585 | record_failed_login(user, |
| 586 | get_canonical_hostname(options.use_dns), "ssh"); |
| 587 | #endif |
| 588 | #ifdef SSH_AUDIT_EVENTS |
| 589 | audit_event(SSH_INVALID_USER); |
| 590 | #endif /* SSH_AUDIT_EVENTS */ |
| 591 | return (NULL); |
| 592 | } |
| 593 | if (!allowed_user(pw)) |
| 594 | return (NULL); |
| 595 | #ifdef HAVE_LOGIN_CAP |
| 596 | if ((lc = login_getclass(pw->pw_class)) == NULL) { |
| 597 | debug("unable to get login class: %s", user); |
| 598 | return (NULL); |
| 599 | } |
| 600 | #ifdef BSD_AUTH |
| 601 | if ((as = auth_open()) == NULL || auth_setpwd(as, pw) != 0 || |
| 602 | auth_approval(as, lc, pw->pw_name, "ssh") <= 0) { |
| 603 | debug("Approval failure for %s", user); |
| 604 | pw = NULL; |
| 605 | } |
| 606 | if (as != NULL) |
| 607 | auth_close(as); |
| 608 | #endif |
| 609 | #endif |
| 610 | if (pw != NULL) |
| 611 | return (pwcopy(pw)); |
| 612 | return (NULL); |
| 613 | } |
| 614 | |
| 615 | /* Returns 1 if key is revoked by revoked_keys_file, 0 otherwise */ |
| 616 | int |
| 617 | auth_key_is_revoked(Key *key) |
| 618 | { |
| 619 | char *key_fp; |
| 620 | |
| 621 | if (options.revoked_keys_file == NULL) |
| 622 | return 0; |
| 623 | |
| 624 | switch (key_in_file(key, options.revoked_keys_file, 0)) { |
| 625 | case 0: |
| 626 | /* key not revoked */ |
| 627 | return 0; |
| 628 | case -1: |
| 629 | /* Error opening revoked_keys_file: refuse all keys */ |
| 630 | error("Revoked keys file is unreadable: refusing public key " |
| 631 | "authentication"); |
| 632 | return 1; |
| 633 | case 1: |
| 634 | /* Key revoked */ |
| 635 | key_fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX); |
| 636 | error("WARNING: authentication attempt with a revoked " |
| 637 | "%s key %s ", key_type(key), key_fp); |
| 638 | xfree(key_fp); |
| 639 | return 1; |
| 640 | } |
| 641 | fatal("key_in_file returned junk"); |
| 642 | } |
| 643 | |
| 644 | void |
| 645 | auth_debug_add(const char *fmt,...) |
| 646 | { |
| 647 | char buf[1024]; |
| 648 | va_list args; |
| 649 | |
| 650 | if (!auth_debug_init) |
| 651 | return; |
| 652 | |
| 653 | va_start(args, fmt); |
| 654 | vsnprintf(buf, sizeof(buf), fmt, args); |
| 655 | va_end(args); |
| 656 | buffer_put_cstring(&auth_debug, buf); |
| 657 | } |
| 658 | |
| 659 | void |
| 660 | auth_debug_send(void) |
| 661 | { |
| 662 | char *msg; |
| 663 | |
| 664 | if (!auth_debug_init) |
| 665 | return; |
| 666 | while (buffer_len(&auth_debug)) { |
| 667 | msg = buffer_get_string(&auth_debug, NULL); |
| 668 | packet_send_debug("%s", msg); |
| 669 | xfree(msg); |
| 670 | } |
| 671 | } |
| 672 | |
| 673 | void |
| 674 | auth_debug_reset(void) |
| 675 | { |
| 676 | if (auth_debug_init) |
| 677 | buffer_clear(&auth_debug); |
| 678 | else { |
| 679 | buffer_init(&auth_debug); |
| 680 | auth_debug_init = 1; |
| 681 | } |
| 682 | } |
| 683 | |
| 684 | struct passwd * |
| 685 | fakepw(void) |
| 686 | { |
| 687 | static struct passwd fake; |
| 688 | |
| 689 | memset(&fake, 0, sizeof(fake)); |
| 690 | fake.pw_name = "NOUSER"; |
| 691 | fake.pw_passwd = |
| 692 | "$2a$06$r3.juUaHZDlIbQaO2dS9FuYxL1W9M81R1Tc92PoSNmzvpEqLkLGrK"; |
| 693 | #ifdef HAVE_PW_GECOS_IN_PASSWD |
| 694 | fake.pw_gecos = "NOUSER"; |
| 695 | #endif |
| 696 | fake.pw_uid = privsep_pw == NULL ? (uid_t)-1 : privsep_pw->pw_uid; |
| 697 | fake.pw_gid = privsep_pw == NULL ? (gid_t)-1 : privsep_pw->pw_gid; |
| 698 | #ifdef HAVE_PW_CLASS_IN_PASSWD |
| 699 | fake.pw_class = ""; |
| 700 | #endif |
| 701 | fake.pw_dir = "/nonexist"; |
| 702 | fake.pw_shell = "/nonexist"; |
| 703 | |
| 704 | return (&fake); |
| 705 | } |