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) {
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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}
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