1 /* $OpenBSD: hostfile.c,v 1.82 2020/06/26 05:42:16 djm Exp $ */ 2 /* 3 * Author: Tatu Ylonen <ylo@cs.hut.fi> 4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 5 * All rights reserved 6 * Functions for manipulating the known hosts files. 7 * 8 * As far as I am concerned, the code I have written for this software 9 * can be used freely for any purpose. Any derived versions of this 10 * software must be clearly marked as such, and if the derived work is 11 * incompatible with the protocol description in the RFC file, it must be 12 * called by a name other than "ssh" or "Secure Shell". 13 * 14 * 15 * Copyright (c) 1999, 2000 Markus Friedl. All rights reserved. 16 * Copyright (c) 1999 Niels Provos. All rights reserved. 17 * 18 * Redistribution and use in source and binary forms, with or without 19 * modification, are permitted provided that the following conditions 20 * are met: 21 * 1. Redistributions of source code must retain the above copyright 22 * notice, this list of conditions and the following disclaimer. 23 * 2. Redistributions in binary form must reproduce the above copyright 24 * notice, this list of conditions and the following disclaimer in the 25 * documentation and/or other materials provided with the distribution. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 28 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 29 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 30 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 31 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 32 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 33 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 34 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 35 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 36 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39 #include <sys/types.h> 40 #include <sys/stat.h> 41 42 #include <netinet/in.h> 43 44 #include <errno.h> 45 #include <resolv.h> 46 #include <stdio.h> 47 #include <stdlib.h> 48 #include <string.h> 49 #include <stdarg.h> 50 #include <unistd.h> 51 52 #include "xmalloc.h" 53 #include "match.h" 54 #include "sshkey.h" 55 #include "hostfile.h" 56 #include "log.h" 57 #include "misc.h" 58 #include "pathnames.h" 59 #include "ssherr.h" 60 #include "digest.h" 61 #include "hmac.h" 62 63 struct hostkeys { 64 struct hostkey_entry *entries; 65 u_int num_entries; 66 }; 67 68 /* XXX hmac is too easy to dictionary attack; use bcrypt? */ 69 70 static int 71 extract_salt(const char *s, u_int l, u_char *salt, size_t salt_len) 72 { 73 char *p, *b64salt; 74 u_int b64len; 75 int ret; 76 77 if (l < sizeof(HASH_MAGIC) - 1) { 78 debug2("extract_salt: string too short"); 79 return (-1); 80 } 81 if (strncmp(s, HASH_MAGIC, sizeof(HASH_MAGIC) - 1) != 0) { 82 debug2("extract_salt: invalid magic identifier"); 83 return (-1); 84 } 85 s += sizeof(HASH_MAGIC) - 1; 86 l -= sizeof(HASH_MAGIC) - 1; 87 if ((p = memchr(s, HASH_DELIM, l)) == NULL) { 88 debug2("extract_salt: missing salt termination character"); 89 return (-1); 90 } 91 92 b64len = p - s; 93 /* Sanity check */ 94 if (b64len == 0 || b64len > 1024) { 95 debug2("extract_salt: bad encoded salt length %u", b64len); 96 return (-1); 97 } 98 b64salt = xmalloc(1 + b64len); 99 memcpy(b64salt, s, b64len); 100 b64salt[b64len] = '\0'; 101 102 ret = __b64_pton(b64salt, salt, salt_len); 103 free(b64salt); 104 if (ret == -1) { 105 debug2("extract_salt: salt decode error"); 106 return (-1); 107 } 108 if (ret != (int)ssh_hmac_bytes(SSH_DIGEST_SHA1)) { 109 debug2("extract_salt: expected salt len %zd, got %d", 110 ssh_hmac_bytes(SSH_DIGEST_SHA1), ret); 111 return (-1); 112 } 113 114 return (0); 115 } 116 117 char * 118 host_hash(const char *host, const char *name_from_hostfile, u_int src_len) 119 { 120 struct ssh_hmac_ctx *ctx; 121 u_char salt[256], result[256]; 122 char uu_salt[512], uu_result[512]; 123 static char encoded[1024]; 124 u_int len; 125 126 len = ssh_digest_bytes(SSH_DIGEST_SHA1); 127 128 if (name_from_hostfile == NULL) { 129 /* Create new salt */ 130 arc4random_buf(salt, len); 131 } else { 132 /* Extract salt from known host entry */ 133 if (extract_salt(name_from_hostfile, src_len, salt, 134 sizeof(salt)) == -1) 135 return (NULL); 136 } 137 138 if ((ctx = ssh_hmac_start(SSH_DIGEST_SHA1)) == NULL || 139 ssh_hmac_init(ctx, salt, len) < 0 || 140 ssh_hmac_update(ctx, host, strlen(host)) < 0 || 141 ssh_hmac_final(ctx, result, sizeof(result))) 142 fatal("%s: ssh_hmac failed", __func__); 143 ssh_hmac_free(ctx); 144 145 if (__b64_ntop(salt, len, uu_salt, sizeof(uu_salt)) == -1 || 146 __b64_ntop(result, len, uu_result, sizeof(uu_result)) == -1) 147 fatal("%s: __b64_ntop failed", __func__); 148 149 snprintf(encoded, sizeof(encoded), "%s%s%c%s", HASH_MAGIC, uu_salt, 150 HASH_DELIM, uu_result); 151 152 return (encoded); 153 } 154 155 /* 156 * Parses an RSA (number of bits, e, n) or DSA key from a string. Moves the 157 * pointer over the key. Skips any whitespace at the beginning and at end. 158 */ 159 160 int 161 hostfile_read_key(char **cpp, u_int *bitsp, struct sshkey *ret) 162 { 163 char *cp; 164 165 /* Skip leading whitespace. */ 166 for (cp = *cpp; *cp == ' ' || *cp == '\t'; cp++) 167 ; 168 169 if (sshkey_read(ret, &cp) != 0) 170 return 0; 171 172 /* Skip trailing whitespace. */ 173 for (; *cp == ' ' || *cp == '\t'; cp++) 174 ; 175 176 /* Return results. */ 177 *cpp = cp; 178 if (bitsp != NULL) 179 *bitsp = sshkey_size(ret); 180 return 1; 181 } 182 183 static HostkeyMarker 184 check_markers(char **cpp) 185 { 186 char marker[32], *sp, *cp = *cpp; 187 int ret = MRK_NONE; 188 189 while (*cp == '@') { 190 /* Only one marker is allowed */ 191 if (ret != MRK_NONE) 192 return MRK_ERROR; 193 /* Markers are terminated by whitespace */ 194 if ((sp = strchr(cp, ' ')) == NULL && 195 (sp = strchr(cp, '\t')) == NULL) 196 return MRK_ERROR; 197 /* Extract marker for comparison */ 198 if (sp <= cp + 1 || sp >= cp + sizeof(marker)) 199 return MRK_ERROR; 200 memcpy(marker, cp, sp - cp); 201 marker[sp - cp] = '\0'; 202 if (strcmp(marker, CA_MARKER) == 0) 203 ret = MRK_CA; 204 else if (strcmp(marker, REVOKE_MARKER) == 0) 205 ret = MRK_REVOKE; 206 else 207 return MRK_ERROR; 208 209 /* Skip past marker and any whitespace that follows it */ 210 cp = sp; 211 for (; *cp == ' ' || *cp == '\t'; cp++) 212 ; 213 } 214 *cpp = cp; 215 return ret; 216 } 217 218 struct hostkeys * 219 init_hostkeys(void) 220 { 221 struct hostkeys *ret = xcalloc(1, sizeof(*ret)); 222 223 ret->entries = NULL; 224 return ret; 225 } 226 227 struct load_callback_ctx { 228 const char *host; 229 u_long num_loaded; 230 struct hostkeys *hostkeys; 231 }; 232 233 static int 234 record_hostkey(struct hostkey_foreach_line *l, void *_ctx) 235 { 236 struct load_callback_ctx *ctx = (struct load_callback_ctx *)_ctx; 237 struct hostkeys *hostkeys = ctx->hostkeys; 238 struct hostkey_entry *tmp; 239 240 if (l->status == HKF_STATUS_INVALID) { 241 /* XXX make this verbose() in the future */ 242 debug("%s:%ld: parse error in hostkeys file", 243 l->path, l->linenum); 244 return 0; 245 } 246 247 debug3("%s: found %skey type %s in file %s:%lu", __func__, 248 l->marker == MRK_NONE ? "" : 249 (l->marker == MRK_CA ? "ca " : "revoked "), 250 sshkey_type(l->key), l->path, l->linenum); 251 if ((tmp = recallocarray(hostkeys->entries, hostkeys->num_entries, 252 hostkeys->num_entries + 1, sizeof(*hostkeys->entries))) == NULL) 253 return SSH_ERR_ALLOC_FAIL; 254 hostkeys->entries = tmp; 255 hostkeys->entries[hostkeys->num_entries].host = xstrdup(ctx->host); 256 hostkeys->entries[hostkeys->num_entries].file = xstrdup(l->path); 257 hostkeys->entries[hostkeys->num_entries].line = l->linenum; 258 hostkeys->entries[hostkeys->num_entries].key = l->key; 259 l->key = NULL; /* steal it */ 260 hostkeys->entries[hostkeys->num_entries].marker = l->marker; 261 hostkeys->num_entries++; 262 ctx->num_loaded++; 263 264 return 0; 265 } 266 267 void 268 load_hostkeys(struct hostkeys *hostkeys, const char *host, const char *path) 269 { 270 int r; 271 struct load_callback_ctx ctx; 272 273 ctx.host = host; 274 ctx.num_loaded = 0; 275 ctx.hostkeys = hostkeys; 276 277 if ((r = hostkeys_foreach(path, record_hostkey, &ctx, host, NULL, 278 HKF_WANT_MATCH|HKF_WANT_PARSE_KEY)) != 0) { 279 if (r != SSH_ERR_SYSTEM_ERROR && errno != ENOENT) 280 debug("%s: hostkeys_foreach failed for %s: %s", 281 __func__, path, ssh_err(r)); 282 } 283 if (ctx.num_loaded != 0) 284 debug3("%s: loaded %lu keys from %s", __func__, 285 ctx.num_loaded, host); 286 } 287 288 void 289 free_hostkeys(struct hostkeys *hostkeys) 290 { 291 u_int i; 292 293 for (i = 0; i < hostkeys->num_entries; i++) { 294 free(hostkeys->entries[i].host); 295 free(hostkeys->entries[i].file); 296 sshkey_free(hostkeys->entries[i].key); 297 explicit_bzero(hostkeys->entries + i, sizeof(*hostkeys->entries)); 298 } 299 free(hostkeys->entries); 300 freezero(hostkeys, sizeof(*hostkeys)); 301 } 302 303 static int 304 check_key_not_revoked(struct hostkeys *hostkeys, struct sshkey *k) 305 { 306 int is_cert = sshkey_is_cert(k); 307 u_int i; 308 309 for (i = 0; i < hostkeys->num_entries; i++) { 310 if (hostkeys->entries[i].marker != MRK_REVOKE) 311 continue; 312 if (sshkey_equal_public(k, hostkeys->entries[i].key)) 313 return -1; 314 if (is_cert && k != NULL && 315 sshkey_equal_public(k->cert->signature_key, 316 hostkeys->entries[i].key)) 317 return -1; 318 } 319 return 0; 320 } 321 322 /* 323 * Match keys against a specified key, or look one up by key type. 324 * 325 * If looking for a keytype (key == NULL) and one is found then return 326 * HOST_FOUND, otherwise HOST_NEW. 327 * 328 * If looking for a key (key != NULL): 329 * 1. If the key is a cert and a matching CA is found, return HOST_OK 330 * 2. If the key is not a cert and a matching key is found, return HOST_OK 331 * 3. If no key matches but a key with a different type is found, then 332 * return HOST_CHANGED 333 * 4. If no matching keys are found, then return HOST_NEW. 334 * 335 * Finally, check any found key is not revoked. 336 */ 337 static HostStatus 338 check_hostkeys_by_key_or_type(struct hostkeys *hostkeys, 339 struct sshkey *k, int keytype, const struct hostkey_entry **found) 340 { 341 u_int i; 342 HostStatus end_return = HOST_NEW; 343 int want_cert = sshkey_is_cert(k); 344 HostkeyMarker want_marker = want_cert ? MRK_CA : MRK_NONE; 345 346 if (found != NULL) 347 *found = NULL; 348 349 for (i = 0; i < hostkeys->num_entries; i++) { 350 if (hostkeys->entries[i].marker != want_marker) 351 continue; 352 if (k == NULL) { 353 if (hostkeys->entries[i].key->type != keytype) 354 continue; 355 end_return = HOST_FOUND; 356 if (found != NULL) 357 *found = hostkeys->entries + i; 358 k = hostkeys->entries[i].key; 359 break; 360 } 361 if (want_cert) { 362 if (sshkey_equal_public(k->cert->signature_key, 363 hostkeys->entries[i].key)) { 364 /* A matching CA exists */ 365 end_return = HOST_OK; 366 if (found != NULL) 367 *found = hostkeys->entries + i; 368 break; 369 } 370 } else { 371 if (sshkey_equal(k, hostkeys->entries[i].key)) { 372 end_return = HOST_OK; 373 if (found != NULL) 374 *found = hostkeys->entries + i; 375 break; 376 } 377 /* A non-maching key exists */ 378 end_return = HOST_CHANGED; 379 if (found != NULL) 380 *found = hostkeys->entries + i; 381 } 382 } 383 if (check_key_not_revoked(hostkeys, k) != 0) { 384 end_return = HOST_REVOKED; 385 if (found != NULL) 386 *found = NULL; 387 } 388 return end_return; 389 } 390 391 HostStatus 392 check_key_in_hostkeys(struct hostkeys *hostkeys, struct sshkey *key, 393 const struct hostkey_entry **found) 394 { 395 if (key == NULL) 396 fatal("no key to look up"); 397 return check_hostkeys_by_key_or_type(hostkeys, key, 0, found); 398 } 399 400 int 401 lookup_key_in_hostkeys_by_type(struct hostkeys *hostkeys, int keytype, 402 const struct hostkey_entry **found) 403 { 404 return (check_hostkeys_by_key_or_type(hostkeys, NULL, keytype, 405 found) == HOST_FOUND); 406 } 407 408 int 409 lookup_marker_in_hostkeys(struct hostkeys *hostkeys, int want_marker) 410 { 411 u_int i; 412 413 for (i = 0; i < hostkeys->num_entries; i++) { 414 if (hostkeys->entries[i].marker == (HostkeyMarker)want_marker) 415 return 1; 416 } 417 return 0; 418 } 419 420 static int 421 write_host_entry(FILE *f, const char *host, const char *ip, 422 const struct sshkey *key, int store_hash) 423 { 424 int r, success = 0; 425 char *hashed_host = NULL, *lhost; 426 427 lhost = xstrdup(host); 428 lowercase(lhost); 429 430 if (store_hash) { 431 if ((hashed_host = host_hash(lhost, NULL, 0)) == NULL) { 432 error("%s: host_hash failed", __func__); 433 free(lhost); 434 return 0; 435 } 436 fprintf(f, "%s ", hashed_host); 437 } else if (ip != NULL) 438 fprintf(f, "%s,%s ", lhost, ip); 439 else { 440 fprintf(f, "%s ", lhost); 441 } 442 free(lhost); 443 if ((r = sshkey_write(key, f)) == 0) 444 success = 1; 445 else 446 error("%s: sshkey_write failed: %s", __func__, ssh_err(r)); 447 fputc('\n', f); 448 return success; 449 } 450 451 /* 452 * Create user ~/.ssh directory if it doesn't exist and we want to write to it. 453 * If notify is set, a message will be emitted if the directory is created. 454 */ 455 void 456 hostfile_create_user_ssh_dir(const char *filename, int notify) 457 { 458 char *dotsshdir = NULL, *p; 459 size_t len; 460 struct stat st; 461 462 if ((p = strrchr(filename, '/')) == NULL) 463 return; 464 len = p - filename; 465 dotsshdir = tilde_expand_filename("~/" _PATH_SSH_USER_DIR, getuid()); 466 if (strlen(dotsshdir) > len || strncmp(filename, dotsshdir, len) != 0) 467 goto out; /* not ~/.ssh prefixed */ 468 if (stat(dotsshdir, &st) == 0) 469 goto out; /* dir already exists */ 470 else if (errno != ENOENT) 471 error("Could not stat %s: %s", dotsshdir, strerror(errno)); 472 else { 473 if (mkdir(dotsshdir, 0700) == -1) 474 error("Could not create directory '%.200s' (%s).", 475 dotsshdir, strerror(errno)); 476 else if (notify) 477 logit("Created directory '%s'.", dotsshdir); 478 } 479 out: 480 free(dotsshdir); 481 } 482 483 484 /* 485 * Appends an entry to the host file. Returns false if the entry could not 486 * be appended. 487 */ 488 int 489 add_host_to_hostfile(const char *filename, const char *host, 490 const struct sshkey *key, int store_hash) 491 { 492 FILE *f; 493 int success; 494 495 if (key == NULL) 496 return 1; /* XXX ? */ 497 hostfile_create_user_ssh_dir(filename, 0); 498 f = fopen(filename, "a"); 499 if (!f) 500 return 0; 501 success = write_host_entry(f, host, NULL, key, store_hash); 502 fclose(f); 503 return success; 504 } 505 506 struct host_delete_ctx { 507 FILE *out; 508 int quiet; 509 const char *host; 510 int *skip_keys; /* XXX split for host/ip? might want to ensure both */ 511 struct sshkey * const *keys; 512 size_t nkeys; 513 int modified; 514 }; 515 516 static int 517 host_delete(struct hostkey_foreach_line *l, void *_ctx) 518 { 519 struct host_delete_ctx *ctx = (struct host_delete_ctx *)_ctx; 520 int loglevel = ctx->quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE; 521 size_t i; 522 523 if (l->status == HKF_STATUS_MATCHED) { 524 if (l->marker != MRK_NONE) { 525 /* Don't remove CA and revocation lines */ 526 fprintf(ctx->out, "%s\n", l->line); 527 return 0; 528 } 529 530 /* 531 * If this line contains one of the keys that we will be 532 * adding later, then don't change it and mark the key for 533 * skipping. 534 */ 535 for (i = 0; i < ctx->nkeys; i++) { 536 if (sshkey_equal(ctx->keys[i], l->key)) { 537 ctx->skip_keys[i] = 1; 538 fprintf(ctx->out, "%s\n", l->line); 539 debug3("%s: %s key already at %s:%ld", __func__, 540 sshkey_type(l->key), l->path, l->linenum); 541 return 0; 542 } 543 } 544 545 /* 546 * Hostname matches and has no CA/revoke marker, delete it 547 * by *not* writing the line to ctx->out. 548 */ 549 do_log2(loglevel, "%s%s%s:%ld: Removed %s key for host %s", 550 ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "", 551 l->path, l->linenum, sshkey_type(l->key), ctx->host); 552 ctx->modified = 1; 553 return 0; 554 } 555 /* Retain non-matching hosts and invalid lines when deleting */ 556 if (l->status == HKF_STATUS_INVALID) { 557 do_log2(loglevel, "%s%s%s:%ld: invalid known_hosts entry", 558 ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "", 559 l->path, l->linenum); 560 } 561 fprintf(ctx->out, "%s\n", l->line); 562 return 0; 563 } 564 565 int 566 hostfile_replace_entries(const char *filename, const char *host, const char *ip, 567 struct sshkey **keys, size_t nkeys, int store_hash, int quiet, int hash_alg) 568 { 569 int r, fd, oerrno = 0; 570 int loglevel = quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE; 571 struct host_delete_ctx ctx; 572 char *fp, *temp = NULL, *back = NULL; 573 mode_t omask; 574 size_t i; 575 576 omask = umask(077); 577 578 memset(&ctx, 0, sizeof(ctx)); 579 ctx.host = host; 580 ctx.quiet = quiet; 581 if ((ctx.skip_keys = calloc(nkeys, sizeof(*ctx.skip_keys))) == NULL) 582 return SSH_ERR_ALLOC_FAIL; 583 ctx.keys = keys; 584 ctx.nkeys = nkeys; 585 ctx.modified = 0; 586 587 /* 588 * Prepare temporary file for in-place deletion. 589 */ 590 if ((r = asprintf(&temp, "%s.XXXXXXXXXXX", filename)) == -1 || 591 (r = asprintf(&back, "%s.old", filename)) == -1) { 592 r = SSH_ERR_ALLOC_FAIL; 593 goto fail; 594 } 595 596 if ((fd = mkstemp(temp)) == -1) { 597 oerrno = errno; 598 error("%s: mkstemp: %s", __func__, strerror(oerrno)); 599 r = SSH_ERR_SYSTEM_ERROR; 600 goto fail; 601 } 602 if ((ctx.out = fdopen(fd, "w")) == NULL) { 603 oerrno = errno; 604 close(fd); 605 error("%s: fdopen: %s", __func__, strerror(oerrno)); 606 r = SSH_ERR_SYSTEM_ERROR; 607 goto fail; 608 } 609 610 /* Remove all entries for the specified host from the file */ 611 if ((r = hostkeys_foreach(filename, host_delete, &ctx, host, ip, 612 HKF_WANT_PARSE_KEY)) != 0) { 613 oerrno = errno; 614 error("%s: hostkeys_foreach failed: %s", __func__, ssh_err(r)); 615 goto fail; 616 } 617 618 /* Add the requested keys */ 619 for (i = 0; i < nkeys; i++) { 620 if (ctx.skip_keys[i]) 621 continue; 622 if ((fp = sshkey_fingerprint(keys[i], hash_alg, 623 SSH_FP_DEFAULT)) == NULL) { 624 r = SSH_ERR_ALLOC_FAIL; 625 goto fail; 626 } 627 do_log2(loglevel, "%s%sAdding new key for %s to %s: %s %s", 628 quiet ? __func__ : "", quiet ? ": " : "", host, filename, 629 sshkey_ssh_name(keys[i]), fp); 630 free(fp); 631 if (!write_host_entry(ctx.out, host, ip, keys[i], store_hash)) { 632 r = SSH_ERR_INTERNAL_ERROR; 633 goto fail; 634 } 635 ctx.modified = 1; 636 } 637 fclose(ctx.out); 638 ctx.out = NULL; 639 640 if (ctx.modified) { 641 /* Backup the original file and replace it with the temporary */ 642 if (unlink(back) == -1 && errno != ENOENT) { 643 oerrno = errno; 644 error("%s: unlink %.100s: %s", __func__, 645 back, strerror(errno)); 646 r = SSH_ERR_SYSTEM_ERROR; 647 goto fail; 648 } 649 if (link(filename, back) == -1) { 650 oerrno = errno; 651 error("%s: link %.100s to %.100s: %s", __func__, 652 filename, back, strerror(errno)); 653 r = SSH_ERR_SYSTEM_ERROR; 654 goto fail; 655 } 656 if (rename(temp, filename) == -1) { 657 oerrno = errno; 658 error("%s: rename \"%s\" to \"%s\": %s", __func__, 659 temp, filename, strerror(errno)); 660 r = SSH_ERR_SYSTEM_ERROR; 661 goto fail; 662 } 663 } else { 664 /* No changes made; just delete the temporary file */ 665 if (unlink(temp) != 0) 666 error("%s: unlink \"%s\": %s", __func__, 667 temp, strerror(errno)); 668 } 669 670 /* success */ 671 r = 0; 672 fail: 673 if (temp != NULL && r != 0) 674 unlink(temp); 675 free(temp); 676 free(back); 677 if (ctx.out != NULL) 678 fclose(ctx.out); 679 free(ctx.skip_keys); 680 umask(omask); 681 if (r == SSH_ERR_SYSTEM_ERROR) 682 errno = oerrno; 683 return r; 684 } 685 686 static int 687 match_maybe_hashed(const char *host, const char *names, int *was_hashed) 688 { 689 int hashed = *names == HASH_DELIM; 690 const char *hashed_host; 691 size_t nlen = strlen(names); 692 693 if (was_hashed != NULL) 694 *was_hashed = hashed; 695 if (hashed) { 696 if ((hashed_host = host_hash(host, names, nlen)) == NULL) 697 return -1; 698 return nlen == strlen(hashed_host) && 699 strncmp(hashed_host, names, nlen) == 0; 700 } 701 return match_hostname(host, names) == 1; 702 } 703 704 int 705 hostkeys_foreach(const char *path, hostkeys_foreach_fn *callback, void *ctx, 706 const char *host, const char *ip, u_int options) 707 { 708 FILE *f; 709 char *line = NULL, ktype[128]; 710 u_long linenum = 0; 711 char *cp, *cp2; 712 u_int kbits; 713 int hashed; 714 int s, r = 0; 715 struct hostkey_foreach_line lineinfo; 716 size_t linesize = 0, l; 717 718 memset(&lineinfo, 0, sizeof(lineinfo)); 719 if (host == NULL && (options & HKF_WANT_MATCH) != 0) 720 return SSH_ERR_INVALID_ARGUMENT; 721 if ((f = fopen(path, "r")) == NULL) 722 return SSH_ERR_SYSTEM_ERROR; 723 724 debug3("%s: reading file \"%s\"", __func__, path); 725 while (getline(&line, &linesize, f) != -1) { 726 linenum++; 727 line[strcspn(line, "\n")] = '\0'; 728 729 free(lineinfo.line); 730 sshkey_free(lineinfo.key); 731 memset(&lineinfo, 0, sizeof(lineinfo)); 732 lineinfo.path = path; 733 lineinfo.linenum = linenum; 734 lineinfo.line = xstrdup(line); 735 lineinfo.marker = MRK_NONE; 736 lineinfo.status = HKF_STATUS_OK; 737 lineinfo.keytype = KEY_UNSPEC; 738 739 /* Skip any leading whitespace, comments and empty lines. */ 740 for (cp = line; *cp == ' ' || *cp == '\t'; cp++) 741 ; 742 if (!*cp || *cp == '#' || *cp == '\n') { 743 if ((options & HKF_WANT_MATCH) == 0) { 744 lineinfo.status = HKF_STATUS_COMMENT; 745 if ((r = callback(&lineinfo, ctx)) != 0) 746 break; 747 } 748 continue; 749 } 750 751 if ((lineinfo.marker = check_markers(&cp)) == MRK_ERROR) { 752 verbose("%s: invalid marker at %s:%lu", 753 __func__, path, linenum); 754 if ((options & HKF_WANT_MATCH) == 0) 755 goto bad; 756 continue; 757 } 758 759 /* Find the end of the host name portion. */ 760 for (cp2 = cp; *cp2 && *cp2 != ' ' && *cp2 != '\t'; cp2++) 761 ; 762 lineinfo.hosts = cp; 763 *cp2++ = '\0'; 764 765 /* Check if the host name matches. */ 766 if (host != NULL) { 767 if ((s = match_maybe_hashed(host, lineinfo.hosts, 768 &hashed)) == -1) { 769 debug2("%s: %s:%ld: bad host hash \"%.32s\"", 770 __func__, path, linenum, lineinfo.hosts); 771 goto bad; 772 } 773 if (s == 1) { 774 lineinfo.status = HKF_STATUS_MATCHED; 775 lineinfo.match |= HKF_MATCH_HOST | 776 (hashed ? HKF_MATCH_HOST_HASHED : 0); 777 } 778 /* Try matching IP address if supplied */ 779 if (ip != NULL) { 780 if ((s = match_maybe_hashed(ip, lineinfo.hosts, 781 &hashed)) == -1) { 782 debug2("%s: %s:%ld: bad ip hash " 783 "\"%.32s\"", __func__, path, 784 linenum, lineinfo.hosts); 785 goto bad; 786 } 787 if (s == 1) { 788 lineinfo.status = HKF_STATUS_MATCHED; 789 lineinfo.match |= HKF_MATCH_IP | 790 (hashed ? HKF_MATCH_IP_HASHED : 0); 791 } 792 } 793 /* 794 * Skip this line if host matching requested and 795 * neither host nor address matched. 796 */ 797 if ((options & HKF_WANT_MATCH) != 0 && 798 lineinfo.status != HKF_STATUS_MATCHED) 799 continue; 800 } 801 802 /* Got a match. Skip host name and any following whitespace */ 803 for (; *cp2 == ' ' || *cp2 == '\t'; cp2++) 804 ; 805 if (*cp2 == '\0' || *cp2 == '#') { 806 debug2("%s:%ld: truncated before key type", 807 path, linenum); 808 goto bad; 809 } 810 lineinfo.rawkey = cp = cp2; 811 812 if ((options & HKF_WANT_PARSE_KEY) != 0) { 813 /* 814 * Extract the key from the line. This will skip 815 * any leading whitespace. Ignore badly formatted 816 * lines. 817 */ 818 if ((lineinfo.key = sshkey_new(KEY_UNSPEC)) == NULL) { 819 error("%s: sshkey_new failed", __func__); 820 r = SSH_ERR_ALLOC_FAIL; 821 break; 822 } 823 if (!hostfile_read_key(&cp, &kbits, lineinfo.key)) { 824 goto bad; 825 } 826 lineinfo.keytype = lineinfo.key->type; 827 lineinfo.comment = cp; 828 } else { 829 /* Extract and parse key type */ 830 l = strcspn(lineinfo.rawkey, " \t"); 831 if (l <= 1 || l >= sizeof(ktype) || 832 lineinfo.rawkey[l] == '\0') 833 goto bad; 834 memcpy(ktype, lineinfo.rawkey, l); 835 ktype[l] = '\0'; 836 lineinfo.keytype = sshkey_type_from_name(ktype); 837 838 /* 839 * Assume legacy RSA1 if the first component is a short 840 * decimal number. 841 */ 842 if (lineinfo.keytype == KEY_UNSPEC && l < 8 && 843 strspn(ktype, "0123456789") == l) 844 goto bad; 845 846 /* 847 * Check that something other than whitespace follows 848 * the key type. This won't catch all corruption, but 849 * it does catch trivial truncation. 850 */ 851 cp2 += l; /* Skip past key type */ 852 for (; *cp2 == ' ' || *cp2 == '\t'; cp2++) 853 ; 854 if (*cp2 == '\0' || *cp2 == '#') { 855 debug2("%s:%ld: truncated after key type", 856 path, linenum); 857 lineinfo.keytype = KEY_UNSPEC; 858 } 859 if (lineinfo.keytype == KEY_UNSPEC) { 860 bad: 861 sshkey_free(lineinfo.key); 862 lineinfo.key = NULL; 863 lineinfo.status = HKF_STATUS_INVALID; 864 if ((r = callback(&lineinfo, ctx)) != 0) 865 break; 866 continue; 867 } 868 } 869 if ((r = callback(&lineinfo, ctx)) != 0) 870 break; 871 } 872 sshkey_free(lineinfo.key); 873 free(lineinfo.line); 874 free(line); 875 fclose(f); 876 return r; 877 } 878