1 /* $OpenBSD: hostfile.c,v 1.81 2020/06/26 05:02:03 dtucker 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 "includes.h" 40 41 #include <sys/types.h> 42 #include <sys/stat.h> 43 44 #include <netinet/in.h> 45 46 #include <errno.h> 47 #include <resolv.h> 48 #include <stdarg.h> 49 #include <stdio.h> 50 #include <stdlib.h> 51 #include <string.h> 52 #include <unistd.h> 53 54 #include "xmalloc.h" 55 #include "match.h" 56 #include "sshkey.h" 57 #include "hostfile.h" 58 #include "log.h" 59 #include "misc.h" 60 #include "pathnames.h" 61 #include "ssherr.h" 62 #include "digest.h" 63 #include "hmac.h" 64 65 struct hostkeys { 66 struct hostkey_entry *entries; 67 u_int num_entries; 68 }; 69 70 /* XXX hmac is too easy to dictionary attack; use bcrypt? */ 71 72 static int 73 extract_salt(const char *s, u_int l, u_char *salt, size_t salt_len) 74 { 75 char *p, *b64salt; 76 u_int b64len; 77 int ret; 78 79 if (l < sizeof(HASH_MAGIC) - 1) { 80 debug2("extract_salt: string too short"); 81 return (-1); 82 } 83 if (strncmp(s, HASH_MAGIC, sizeof(HASH_MAGIC) - 1) != 0) { 84 debug2("extract_salt: invalid magic identifier"); 85 return (-1); 86 } 87 s += sizeof(HASH_MAGIC) - 1; 88 l -= sizeof(HASH_MAGIC) - 1; 89 if ((p = memchr(s, HASH_DELIM, l)) == NULL) { 90 debug2("extract_salt: missing salt termination character"); 91 return (-1); 92 } 93 94 b64len = p - s; 95 /* Sanity check */ 96 if (b64len == 0 || b64len > 1024) { 97 debug2("extract_salt: bad encoded salt length %u", b64len); 98 return (-1); 99 } 100 b64salt = xmalloc(1 + b64len); 101 memcpy(b64salt, s, b64len); 102 b64salt[b64len] = '\0'; 103 104 ret = __b64_pton(b64salt, salt, salt_len); 105 free(b64salt); 106 if (ret == -1) { 107 debug2("extract_salt: salt decode error"); 108 return (-1); 109 } 110 if (ret != (int)ssh_hmac_bytes(SSH_DIGEST_SHA1)) { 111 debug2("extract_salt: expected salt len %zd, got %d", 112 ssh_hmac_bytes(SSH_DIGEST_SHA1), ret); 113 return (-1); 114 } 115 116 return (0); 117 } 118 119 char * 120 host_hash(const char *host, const char *name_from_hostfile, u_int src_len) 121 { 122 struct ssh_hmac_ctx *ctx; 123 u_char salt[256], result[256]; 124 char uu_salt[512], uu_result[512]; 125 static char encoded[1024]; 126 u_int len; 127 128 len = ssh_digest_bytes(SSH_DIGEST_SHA1); 129 130 if (name_from_hostfile == NULL) { 131 /* Create new salt */ 132 arc4random_buf(salt, len); 133 } else { 134 /* Extract salt from known host entry */ 135 if (extract_salt(name_from_hostfile, src_len, salt, 136 sizeof(salt)) == -1) 137 return (NULL); 138 } 139 140 if ((ctx = ssh_hmac_start(SSH_DIGEST_SHA1)) == NULL || 141 ssh_hmac_init(ctx, salt, len) < 0 || 142 ssh_hmac_update(ctx, host, strlen(host)) < 0 || 143 ssh_hmac_final(ctx, result, sizeof(result))) 144 fatal("%s: ssh_hmac failed", __func__); 145 ssh_hmac_free(ctx); 146 147 if (__b64_ntop(salt, len, uu_salt, sizeof(uu_salt)) == -1 || 148 __b64_ntop(result, len, uu_result, sizeof(uu_result)) == -1) 149 fatal("%s: __b64_ntop failed", __func__); 150 151 snprintf(encoded, sizeof(encoded), "%s%s%c%s", HASH_MAGIC, uu_salt, 152 HASH_DELIM, uu_result); 153 154 return (encoded); 155 } 156 157 /* 158 * Parses an RSA (number of bits, e, n) or DSA key from a string. Moves the 159 * pointer over the key. Skips any whitespace at the beginning and at end. 160 */ 161 162 int 163 hostfile_read_key(char **cpp, u_int *bitsp, struct sshkey *ret) 164 { 165 char *cp; 166 167 /* Skip leading whitespace. */ 168 for (cp = *cpp; *cp == ' ' || *cp == '\t'; cp++) 169 ; 170 171 if (sshkey_read(ret, &cp) != 0) 172 return 0; 173 174 /* Skip trailing whitespace. */ 175 for (; *cp == ' ' || *cp == '\t'; cp++) 176 ; 177 178 /* Return results. */ 179 *cpp = cp; 180 if (bitsp != NULL) 181 *bitsp = sshkey_size(ret); 182 return 1; 183 } 184 185 static HostkeyMarker 186 check_markers(char **cpp) 187 { 188 char marker[32], *sp, *cp = *cpp; 189 int ret = MRK_NONE; 190 191 while (*cp == '@') { 192 /* Only one marker is allowed */ 193 if (ret != MRK_NONE) 194 return MRK_ERROR; 195 /* Markers are terminated by whitespace */ 196 if ((sp = strchr(cp, ' ')) == NULL && 197 (sp = strchr(cp, '\t')) == NULL) 198 return MRK_ERROR; 199 /* Extract marker for comparison */ 200 if (sp <= cp + 1 || sp >= cp + sizeof(marker)) 201 return MRK_ERROR; 202 memcpy(marker, cp, sp - cp); 203 marker[sp - cp] = '\0'; 204 if (strcmp(marker, CA_MARKER) == 0) 205 ret = MRK_CA; 206 else if (strcmp(marker, REVOKE_MARKER) == 0) 207 ret = MRK_REVOKE; 208 else 209 return MRK_ERROR; 210 211 /* Skip past marker and any whitespace that follows it */ 212 cp = sp; 213 for (; *cp == ' ' || *cp == '\t'; cp++) 214 ; 215 } 216 *cpp = cp; 217 return ret; 218 } 219 220 struct hostkeys * 221 init_hostkeys(void) 222 { 223 struct hostkeys *ret = xcalloc(1, sizeof(*ret)); 224 225 ret->entries = NULL; 226 return ret; 227 } 228 229 struct load_callback_ctx { 230 const char *host; 231 u_long num_loaded; 232 struct hostkeys *hostkeys; 233 }; 234 235 static int 236 record_hostkey(struct hostkey_foreach_line *l, void *_ctx) 237 { 238 struct load_callback_ctx *ctx = (struct load_callback_ctx *)_ctx; 239 struct hostkeys *hostkeys = ctx->hostkeys; 240 struct hostkey_entry *tmp; 241 242 if (l->status == HKF_STATUS_INVALID) { 243 /* XXX make this verbose() in the future */ 244 debug("%s:%ld: parse error in hostkeys file", 245 l->path, l->linenum); 246 return 0; 247 } 248 249 debug3("%s: found %skey type %s in file %s:%lu", __func__, 250 l->marker == MRK_NONE ? "" : 251 (l->marker == MRK_CA ? "ca " : "revoked "), 252 sshkey_type(l->key), l->path, l->linenum); 253 if ((tmp = recallocarray(hostkeys->entries, hostkeys->num_entries, 254 hostkeys->num_entries + 1, sizeof(*hostkeys->entries))) == NULL) 255 return SSH_ERR_ALLOC_FAIL; 256 hostkeys->entries = tmp; 257 hostkeys->entries[hostkeys->num_entries].host = xstrdup(ctx->host); 258 hostkeys->entries[hostkeys->num_entries].file = xstrdup(l->path); 259 hostkeys->entries[hostkeys->num_entries].line = l->linenum; 260 hostkeys->entries[hostkeys->num_entries].key = l->key; 261 l->key = NULL; /* steal it */ 262 hostkeys->entries[hostkeys->num_entries].marker = l->marker; 263 hostkeys->num_entries++; 264 ctx->num_loaded++; 265 266 return 0; 267 } 268 269 void 270 load_hostkeys(struct hostkeys *hostkeys, const char *host, const char *path) 271 { 272 int r; 273 struct load_callback_ctx ctx; 274 275 ctx.host = host; 276 ctx.num_loaded = 0; 277 ctx.hostkeys = hostkeys; 278 279 if ((r = hostkeys_foreach(path, record_hostkey, &ctx, host, NULL, 280 HKF_WANT_MATCH|HKF_WANT_PARSE_KEY)) != 0) { 281 if (r != SSH_ERR_SYSTEM_ERROR && errno != ENOENT) 282 debug("%s: hostkeys_foreach failed for %s: %s", 283 __func__, path, ssh_err(r)); 284 } 285 if (ctx.num_loaded != 0) 286 debug3("%s: loaded %lu keys from %s", __func__, 287 ctx.num_loaded, host); 288 } 289 290 void 291 free_hostkeys(struct hostkeys *hostkeys) 292 { 293 u_int i; 294 295 for (i = 0; i < hostkeys->num_entries; i++) { 296 free(hostkeys->entries[i].host); 297 free(hostkeys->entries[i].file); 298 sshkey_free(hostkeys->entries[i].key); 299 explicit_bzero(hostkeys->entries + i, sizeof(*hostkeys->entries)); 300 } 301 free(hostkeys->entries); 302 freezero(hostkeys, sizeof(*hostkeys)); 303 } 304 305 static int 306 check_key_not_revoked(struct hostkeys *hostkeys, struct sshkey *k) 307 { 308 int is_cert = sshkey_is_cert(k); 309 u_int i; 310 311 for (i = 0; i < hostkeys->num_entries; i++) { 312 if (hostkeys->entries[i].marker != MRK_REVOKE) 313 continue; 314 if (sshkey_equal_public(k, hostkeys->entries[i].key)) 315 return -1; 316 if (is_cert && k != NULL && 317 sshkey_equal_public(k->cert->signature_key, 318 hostkeys->entries[i].key)) 319 return -1; 320 } 321 return 0; 322 } 323 324 /* 325 * Match keys against a specified key, or look one up by key type. 326 * 327 * If looking for a keytype (key == NULL) and one is found then return 328 * HOST_FOUND, otherwise HOST_NEW. 329 * 330 * If looking for a key (key != NULL): 331 * 1. If the key is a cert and a matching CA is found, return HOST_OK 332 * 2. If the key is not a cert and a matching key is found, return HOST_OK 333 * 3. If no key matches but a key with a different type is found, then 334 * return HOST_CHANGED 335 * 4. If no matching keys are found, then return HOST_NEW. 336 * 337 * Finally, check any found key is not revoked. 338 */ 339 static HostStatus 340 check_hostkeys_by_key_or_type(struct hostkeys *hostkeys, 341 struct sshkey *k, int keytype, const struct hostkey_entry **found) 342 { 343 u_int i; 344 HostStatus end_return = HOST_NEW; 345 int want_cert = sshkey_is_cert(k); 346 HostkeyMarker want_marker = want_cert ? MRK_CA : MRK_NONE; 347 348 if (found != NULL) 349 *found = NULL; 350 351 for (i = 0; i < hostkeys->num_entries; i++) { 352 if (hostkeys->entries[i].marker != want_marker) 353 continue; 354 if (k == NULL) { 355 if (hostkeys->entries[i].key->type != keytype) 356 continue; 357 end_return = HOST_FOUND; 358 if (found != NULL) 359 *found = hostkeys->entries + i; 360 k = hostkeys->entries[i].key; 361 break; 362 } 363 if (want_cert) { 364 if (sshkey_equal_public(k->cert->signature_key, 365 hostkeys->entries[i].key)) { 366 /* A matching CA exists */ 367 end_return = HOST_OK; 368 if (found != NULL) 369 *found = hostkeys->entries + i; 370 break; 371 } 372 } else { 373 if (sshkey_equal(k, hostkeys->entries[i].key)) { 374 end_return = HOST_OK; 375 if (found != NULL) 376 *found = hostkeys->entries + i; 377 break; 378 } 379 /* A non-maching key exists */ 380 end_return = HOST_CHANGED; 381 if (found != NULL) 382 *found = hostkeys->entries + i; 383 } 384 } 385 if (check_key_not_revoked(hostkeys, k) != 0) { 386 end_return = HOST_REVOKED; 387 if (found != NULL) 388 *found = NULL; 389 } 390 return end_return; 391 } 392 393 HostStatus 394 check_key_in_hostkeys(struct hostkeys *hostkeys, struct sshkey *key, 395 const struct hostkey_entry **found) 396 { 397 if (key == NULL) 398 fatal("no key to look up"); 399 return check_hostkeys_by_key_or_type(hostkeys, key, 0, found); 400 } 401 402 int 403 lookup_key_in_hostkeys_by_type(struct hostkeys *hostkeys, int keytype, 404 const struct hostkey_entry **found) 405 { 406 return (check_hostkeys_by_key_or_type(hostkeys, NULL, keytype, 407 found) == HOST_FOUND); 408 } 409 410 int 411 lookup_marker_in_hostkeys(struct hostkeys *hostkeys, int want_marker) 412 { 413 u_int i; 414 415 for (i = 0; i < hostkeys->num_entries; i++) { 416 if (hostkeys->entries[i].marker == (HostkeyMarker)want_marker) 417 return 1; 418 } 419 return 0; 420 } 421 422 static int 423 write_host_entry(FILE *f, const char *host, const char *ip, 424 const struct sshkey *key, int store_hash) 425 { 426 int r, success = 0; 427 char *hashed_host = NULL, *lhost; 428 429 lhost = xstrdup(host); 430 lowercase(lhost); 431 432 if (store_hash) { 433 if ((hashed_host = host_hash(lhost, NULL, 0)) == NULL) { 434 error("%s: host_hash failed", __func__); 435 free(lhost); 436 return 0; 437 } 438 fprintf(f, "%s ", hashed_host); 439 } else if (ip != NULL) 440 fprintf(f, "%s,%s ", lhost, ip); 441 else { 442 fprintf(f, "%s ", lhost); 443 } 444 free(lhost); 445 if ((r = sshkey_write(key, f)) == 0) 446 success = 1; 447 else 448 error("%s: sshkey_write failed: %s", __func__, ssh_err(r)); 449 fputc('\n', f); 450 return success; 451 } 452 453 /* 454 * Create user ~/.ssh directory if it doesn't exist and we want to write to it. 455 * If notify is set, a message will be emitted if the directory is created. 456 */ 457 void 458 hostfile_create_user_ssh_dir(const char *filename, int notify) 459 { 460 char *dotsshdir = NULL, *p; 461 size_t len; 462 struct stat st; 463 464 if ((p = strrchr(filename, '/')) == NULL) 465 return; 466 len = p - filename; 467 dotsshdir = tilde_expand_filename("~/" _PATH_SSH_USER_DIR, getuid()); 468 if ((strlen(dotsshdir) > len || strncmp(filename, dotsshdir, len) != 0 469 || stat(dotsshdir, &st)) == 0) 470 ; /* do nothing, path not in ~/.ssh or dir already exists */ 471 else if (errno != ENOENT) 472 error("Could not stat %s: %s", dotsshdir, strerror(errno)); 473 else { 474 #ifdef WITH_SELINUX 475 ssh_selinux_setfscreatecon(dotsshdir); 476 #endif 477 if (mkdir(dotsshdir, 0700) == -1) 478 error("Could not create directory '%.200s' (%s).", 479 dotsshdir, strerror(errno)); 480 else if (notify) 481 logit("Created directory '%s'.", dotsshdir); 482 #ifdef WITH_SELINUX 483 ssh_selinux_setfscreatecon(NULL); 484 #endif 485 } 486 free(dotsshdir); 487 } 488 489 /* 490 * Appends an entry to the host file. Returns false if the entry could not 491 * be appended. 492 */ 493 int 494 add_host_to_hostfile(const char *filename, const char *host, 495 const struct sshkey *key, int store_hash) 496 { 497 FILE *f; 498 int success; 499 500 if (key == NULL) 501 return 1; /* XXX ? */ 502 hostfile_create_user_ssh_dir(filename, 0); 503 f = fopen(filename, "a"); 504 if (!f) 505 return 0; 506 success = write_host_entry(f, host, NULL, key, store_hash); 507 fclose(f); 508 return success; 509 } 510 511 struct host_delete_ctx { 512 FILE *out; 513 int quiet; 514 const char *host; 515 int *skip_keys; /* XXX split for host/ip? might want to ensure both */ 516 struct sshkey * const *keys; 517 size_t nkeys; 518 int modified; 519 }; 520 521 static int 522 host_delete(struct hostkey_foreach_line *l, void *_ctx) 523 { 524 struct host_delete_ctx *ctx = (struct host_delete_ctx *)_ctx; 525 int loglevel = ctx->quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE; 526 size_t i; 527 528 if (l->status == HKF_STATUS_MATCHED) { 529 if (l->marker != MRK_NONE) { 530 /* Don't remove CA and revocation lines */ 531 fprintf(ctx->out, "%s\n", l->line); 532 return 0; 533 } 534 535 /* 536 * If this line contains one of the keys that we will be 537 * adding later, then don't change it and mark the key for 538 * skipping. 539 */ 540 for (i = 0; i < ctx->nkeys; i++) { 541 if (sshkey_equal(ctx->keys[i], l->key)) { 542 ctx->skip_keys[i] = 1; 543 fprintf(ctx->out, "%s\n", l->line); 544 debug3("%s: %s key already at %s:%ld", __func__, 545 sshkey_type(l->key), l->path, l->linenum); 546 return 0; 547 } 548 } 549 550 /* 551 * Hostname matches and has no CA/revoke marker, delete it 552 * by *not* writing the line to ctx->out. 553 */ 554 do_log2(loglevel, "%s%s%s:%ld: Removed %s key for host %s", 555 ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "", 556 l->path, l->linenum, sshkey_type(l->key), ctx->host); 557 ctx->modified = 1; 558 return 0; 559 } 560 /* Retain non-matching hosts and invalid lines when deleting */ 561 if (l->status == HKF_STATUS_INVALID) { 562 do_log2(loglevel, "%s%s%s:%ld: invalid known_hosts entry", 563 ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "", 564 l->path, l->linenum); 565 } 566 fprintf(ctx->out, "%s\n", l->line); 567 return 0; 568 } 569 570 int 571 hostfile_replace_entries(const char *filename, const char *host, const char *ip, 572 struct sshkey **keys, size_t nkeys, int store_hash, int quiet, int hash_alg) 573 { 574 int r, fd, oerrno = 0; 575 int loglevel = quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE; 576 struct host_delete_ctx ctx; 577 char *fp, *temp = NULL, *back = NULL; 578 mode_t omask; 579 size_t i; 580 581 omask = umask(077); 582 583 memset(&ctx, 0, sizeof(ctx)); 584 ctx.host = host; 585 ctx.quiet = quiet; 586 if ((ctx.skip_keys = calloc(nkeys, sizeof(*ctx.skip_keys))) == NULL) 587 return SSH_ERR_ALLOC_FAIL; 588 ctx.keys = keys; 589 ctx.nkeys = nkeys; 590 ctx.modified = 0; 591 592 /* 593 * Prepare temporary file for in-place deletion. 594 */ 595 if ((r = asprintf(&temp, "%s.XXXXXXXXXXX", filename)) == -1 || 596 (r = asprintf(&back, "%s.old", filename)) == -1) { 597 r = SSH_ERR_ALLOC_FAIL; 598 goto fail; 599 } 600 601 if ((fd = mkstemp(temp)) == -1) { 602 oerrno = errno; 603 error("%s: mkstemp: %s", __func__, strerror(oerrno)); 604 r = SSH_ERR_SYSTEM_ERROR; 605 goto fail; 606 } 607 if ((ctx.out = fdopen(fd, "w")) == NULL) { 608 oerrno = errno; 609 close(fd); 610 error("%s: fdopen: %s", __func__, strerror(oerrno)); 611 r = SSH_ERR_SYSTEM_ERROR; 612 goto fail; 613 } 614 615 /* Remove all entries for the specified host from the file */ 616 if ((r = hostkeys_foreach(filename, host_delete, &ctx, host, ip, 617 HKF_WANT_PARSE_KEY)) != 0) { 618 oerrno = errno; 619 error("%s: hostkeys_foreach failed: %s", __func__, ssh_err(r)); 620 goto fail; 621 } 622 623 /* Add the requested keys */ 624 for (i = 0; i < nkeys; i++) { 625 if (ctx.skip_keys[i]) 626 continue; 627 if ((fp = sshkey_fingerprint(keys[i], hash_alg, 628 SSH_FP_DEFAULT)) == NULL) { 629 r = SSH_ERR_ALLOC_FAIL; 630 goto fail; 631 } 632 do_log2(loglevel, "%s%sAdding new key for %s to %s: %s %s", 633 quiet ? __func__ : "", quiet ? ": " : "", host, filename, 634 sshkey_ssh_name(keys[i]), fp); 635 free(fp); 636 if (!write_host_entry(ctx.out, host, ip, keys[i], store_hash)) { 637 r = SSH_ERR_INTERNAL_ERROR; 638 goto fail; 639 } 640 ctx.modified = 1; 641 } 642 fclose(ctx.out); 643 ctx.out = NULL; 644 645 if (ctx.modified) { 646 /* Backup the original file and replace it with the temporary */ 647 if (unlink(back) == -1 && errno != ENOENT) { 648 oerrno = errno; 649 error("%s: unlink %.100s: %s", __func__, 650 back, strerror(errno)); 651 r = SSH_ERR_SYSTEM_ERROR; 652 goto fail; 653 } 654 if (link(filename, back) == -1) { 655 oerrno = errno; 656 error("%s: link %.100s to %.100s: %s", __func__, 657 filename, back, strerror(errno)); 658 r = SSH_ERR_SYSTEM_ERROR; 659 goto fail; 660 } 661 if (rename(temp, filename) == -1) { 662 oerrno = errno; 663 error("%s: rename \"%s\" to \"%s\": %s", __func__, 664 temp, filename, strerror(errno)); 665 r = SSH_ERR_SYSTEM_ERROR; 666 goto fail; 667 } 668 } else { 669 /* No changes made; just delete the temporary file */ 670 if (unlink(temp) != 0) 671 error("%s: unlink \"%s\": %s", __func__, 672 temp, strerror(errno)); 673 } 674 675 /* success */ 676 r = 0; 677 fail: 678 if (temp != NULL && r != 0) 679 unlink(temp); 680 free(temp); 681 free(back); 682 if (ctx.out != NULL) 683 fclose(ctx.out); 684 free(ctx.skip_keys); 685 umask(omask); 686 if (r == SSH_ERR_SYSTEM_ERROR) 687 errno = oerrno; 688 return r; 689 } 690 691 static int 692 match_maybe_hashed(const char *host, const char *names, int *was_hashed) 693 { 694 int hashed = *names == HASH_DELIM; 695 const char *hashed_host; 696 size_t nlen = strlen(names); 697 698 if (was_hashed != NULL) 699 *was_hashed = hashed; 700 if (hashed) { 701 if ((hashed_host = host_hash(host, names, nlen)) == NULL) 702 return -1; 703 return nlen == strlen(hashed_host) && 704 strncmp(hashed_host, names, nlen) == 0; 705 } 706 return match_hostname(host, names) == 1; 707 } 708 709 int 710 hostkeys_foreach(const char *path, hostkeys_foreach_fn *callback, void *ctx, 711 const char *host, const char *ip, u_int options) 712 { 713 FILE *f; 714 char *line = NULL, ktype[128]; 715 u_long linenum = 0; 716 char *cp, *cp2; 717 u_int kbits; 718 int hashed; 719 int s, r = 0; 720 struct hostkey_foreach_line lineinfo; 721 size_t linesize = 0, l; 722 723 memset(&lineinfo, 0, sizeof(lineinfo)); 724 if (host == NULL && (options & HKF_WANT_MATCH) != 0) 725 return SSH_ERR_INVALID_ARGUMENT; 726 if ((f = fopen(path, "r")) == NULL) 727 return SSH_ERR_SYSTEM_ERROR; 728 729 debug3("%s: reading file \"%s\"", __func__, path); 730 while (getline(&line, &linesize, f) != -1) { 731 linenum++; 732 line[strcspn(line, "\n")] = '\0'; 733 734 free(lineinfo.line); 735 sshkey_free(lineinfo.key); 736 memset(&lineinfo, 0, sizeof(lineinfo)); 737 lineinfo.path = path; 738 lineinfo.linenum = linenum; 739 lineinfo.line = xstrdup(line); 740 lineinfo.marker = MRK_NONE; 741 lineinfo.status = HKF_STATUS_OK; 742 lineinfo.keytype = KEY_UNSPEC; 743 744 /* Skip any leading whitespace, comments and empty lines. */ 745 for (cp = line; *cp == ' ' || *cp == '\t'; cp++) 746 ; 747 if (!*cp || *cp == '#' || *cp == '\n') { 748 if ((options & HKF_WANT_MATCH) == 0) { 749 lineinfo.status = HKF_STATUS_COMMENT; 750 if ((r = callback(&lineinfo, ctx)) != 0) 751 break; 752 } 753 continue; 754 } 755 756 if ((lineinfo.marker = check_markers(&cp)) == MRK_ERROR) { 757 verbose("%s: invalid marker at %s:%lu", 758 __func__, path, linenum); 759 if ((options & HKF_WANT_MATCH) == 0) 760 goto bad; 761 continue; 762 } 763 764 /* Find the end of the host name portion. */ 765 for (cp2 = cp; *cp2 && *cp2 != ' ' && *cp2 != '\t'; cp2++) 766 ; 767 lineinfo.hosts = cp; 768 *cp2++ = '\0'; 769 770 /* Check if the host name matches. */ 771 if (host != NULL) { 772 if ((s = match_maybe_hashed(host, lineinfo.hosts, 773 &hashed)) == -1) { 774 debug2("%s: %s:%ld: bad host hash \"%.32s\"", 775 __func__, path, linenum, lineinfo.hosts); 776 goto bad; 777 } 778 if (s == 1) { 779 lineinfo.status = HKF_STATUS_MATCHED; 780 lineinfo.match |= HKF_MATCH_HOST | 781 (hashed ? HKF_MATCH_HOST_HASHED : 0); 782 } 783 /* Try matching IP address if supplied */ 784 if (ip != NULL) { 785 if ((s = match_maybe_hashed(ip, lineinfo.hosts, 786 &hashed)) == -1) { 787 debug2("%s: %s:%ld: bad ip hash " 788 "\"%.32s\"", __func__, path, 789 linenum, lineinfo.hosts); 790 goto bad; 791 } 792 if (s == 1) { 793 lineinfo.status = HKF_STATUS_MATCHED; 794 lineinfo.match |= HKF_MATCH_IP | 795 (hashed ? HKF_MATCH_IP_HASHED : 0); 796 } 797 } 798 /* 799 * Skip this line if host matching requested and 800 * neither host nor address matched. 801 */ 802 if ((options & HKF_WANT_MATCH) != 0 && 803 lineinfo.status != HKF_STATUS_MATCHED) 804 continue; 805 } 806 807 /* Got a match. Skip host name and any following whitespace */ 808 for (; *cp2 == ' ' || *cp2 == '\t'; cp2++) 809 ; 810 if (*cp2 == '\0' || *cp2 == '#') { 811 debug2("%s:%ld: truncated before key type", 812 path, linenum); 813 goto bad; 814 } 815 lineinfo.rawkey = cp = cp2; 816 817 if ((options & HKF_WANT_PARSE_KEY) != 0) { 818 /* 819 * Extract the key from the line. This will skip 820 * any leading whitespace. Ignore badly formatted 821 * lines. 822 */ 823 if ((lineinfo.key = sshkey_new(KEY_UNSPEC)) == NULL) { 824 error("%s: sshkey_new failed", __func__); 825 r = SSH_ERR_ALLOC_FAIL; 826 break; 827 } 828 if (!hostfile_read_key(&cp, &kbits, lineinfo.key)) { 829 goto bad; 830 } 831 lineinfo.keytype = lineinfo.key->type; 832 lineinfo.comment = cp; 833 } else { 834 /* Extract and parse key type */ 835 l = strcspn(lineinfo.rawkey, " \t"); 836 if (l <= 1 || l >= sizeof(ktype) || 837 lineinfo.rawkey[l] == '\0') 838 goto bad; 839 memcpy(ktype, lineinfo.rawkey, l); 840 ktype[l] = '\0'; 841 lineinfo.keytype = sshkey_type_from_name(ktype); 842 843 /* 844 * Assume legacy RSA1 if the first component is a short 845 * decimal number. 846 */ 847 if (lineinfo.keytype == KEY_UNSPEC && l < 8 && 848 strspn(ktype, "0123456789") == l) 849 goto bad; 850 851 /* 852 * Check that something other than whitespace follows 853 * the key type. This won't catch all corruption, but 854 * it does catch trivial truncation. 855 */ 856 cp2 += l; /* Skip past key type */ 857 for (; *cp2 == ' ' || *cp2 == '\t'; cp2++) 858 ; 859 if (*cp2 == '\0' || *cp2 == '#') { 860 debug2("%s:%ld: truncated after key type", 861 path, linenum); 862 lineinfo.keytype = KEY_UNSPEC; 863 } 864 if (lineinfo.keytype == KEY_UNSPEC) { 865 bad: 866 sshkey_free(lineinfo.key); 867 lineinfo.key = NULL; 868 lineinfo.status = HKF_STATUS_INVALID; 869 if ((r = callback(&lineinfo, ctx)) != 0) 870 break; 871 continue; 872 } 873 } 874 if ((r = callback(&lineinfo, ctx)) != 0) 875 break; 876 } 877 sshkey_free(lineinfo.key); 878 free(lineinfo.line); 879 free(line); 880 fclose(f); 881 return r; 882 } 883