1 /* $OpenBSD: hostfile.c,v 1.78 2020/02/26 13:40:09 jsg 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 "ssherr.h" 59 #include "digest.h" 60 #include "hmac.h" 61 62 struct hostkeys { 63 struct hostkey_entry *entries; 64 u_int num_entries; 65 }; 66 67 /* XXX hmac is too easy to dictionary attack; use bcrypt? */ 68 69 static int 70 extract_salt(const char *s, u_int l, u_char *salt, size_t salt_len) 71 { 72 char *p, *b64salt; 73 u_int b64len; 74 int ret; 75 76 if (l < sizeof(HASH_MAGIC) - 1) { 77 debug2("extract_salt: string too short"); 78 return (-1); 79 } 80 if (strncmp(s, HASH_MAGIC, sizeof(HASH_MAGIC) - 1) != 0) { 81 debug2("extract_salt: invalid magic identifier"); 82 return (-1); 83 } 84 s += sizeof(HASH_MAGIC) - 1; 85 l -= sizeof(HASH_MAGIC) - 1; 86 if ((p = memchr(s, HASH_DELIM, l)) == NULL) { 87 debug2("extract_salt: missing salt termination character"); 88 return (-1); 89 } 90 91 b64len = p - s; 92 /* Sanity check */ 93 if (b64len == 0 || b64len > 1024) { 94 debug2("extract_salt: bad encoded salt length %u", b64len); 95 return (-1); 96 } 97 b64salt = xmalloc(1 + b64len); 98 memcpy(b64salt, s, b64len); 99 b64salt[b64len] = '\0'; 100 101 ret = __b64_pton(b64salt, salt, salt_len); 102 free(b64salt); 103 if (ret == -1) { 104 debug2("extract_salt: salt decode error"); 105 return (-1); 106 } 107 if (ret != (int)ssh_hmac_bytes(SSH_DIGEST_SHA1)) { 108 debug2("extract_salt: expected salt len %zd, got %d", 109 ssh_hmac_bytes(SSH_DIGEST_SHA1), ret); 110 return (-1); 111 } 112 113 return (0); 114 } 115 116 char * 117 host_hash(const char *host, const char *name_from_hostfile, u_int src_len) 118 { 119 struct ssh_hmac_ctx *ctx; 120 u_char salt[256], result[256]; 121 char uu_salt[512], uu_result[512]; 122 static char encoded[1024]; 123 u_int len; 124 125 len = ssh_digest_bytes(SSH_DIGEST_SHA1); 126 127 if (name_from_hostfile == NULL) { 128 /* Create new salt */ 129 arc4random_buf(salt, len); 130 } else { 131 /* Extract salt from known host entry */ 132 if (extract_salt(name_from_hostfile, src_len, salt, 133 sizeof(salt)) == -1) 134 return (NULL); 135 } 136 137 if ((ctx = ssh_hmac_start(SSH_DIGEST_SHA1)) == NULL || 138 ssh_hmac_init(ctx, salt, len) < 0 || 139 ssh_hmac_update(ctx, host, strlen(host)) < 0 || 140 ssh_hmac_final(ctx, result, sizeof(result))) 141 fatal("%s: ssh_hmac failed", __func__); 142 ssh_hmac_free(ctx); 143 144 if (__b64_ntop(salt, len, uu_salt, sizeof(uu_salt)) == -1 || 145 __b64_ntop(result, len, uu_result, sizeof(uu_result)) == -1) 146 fatal("%s: __b64_ntop failed", __func__); 147 148 snprintf(encoded, sizeof(encoded), "%s%s%c%s", HASH_MAGIC, uu_salt, 149 HASH_DELIM, uu_result); 150 151 return (encoded); 152 } 153 154 /* 155 * Parses an RSA (number of bits, e, n) or DSA key from a string. Moves the 156 * pointer over the key. Skips any whitespace at the beginning and at end. 157 */ 158 159 int 160 hostfile_read_key(char **cpp, u_int *bitsp, struct sshkey *ret) 161 { 162 char *cp; 163 164 /* Skip leading whitespace. */ 165 for (cp = *cpp; *cp == ' ' || *cp == '\t'; cp++) 166 ; 167 168 if (sshkey_read(ret, &cp) != 0) 169 return 0; 170 171 /* Skip trailing whitespace. */ 172 for (; *cp == ' ' || *cp == '\t'; cp++) 173 ; 174 175 /* Return results. */ 176 *cpp = cp; 177 if (bitsp != NULL) 178 *bitsp = sshkey_size(ret); 179 return 1; 180 } 181 182 static HostkeyMarker 183 check_markers(char **cpp) 184 { 185 char marker[32], *sp, *cp = *cpp; 186 int ret = MRK_NONE; 187 188 while (*cp == '@') { 189 /* Only one marker is allowed */ 190 if (ret != MRK_NONE) 191 return MRK_ERROR; 192 /* Markers are terminated by whitespace */ 193 if ((sp = strchr(cp, ' ')) == NULL && 194 (sp = strchr(cp, '\t')) == NULL) 195 return MRK_ERROR; 196 /* Extract marker for comparison */ 197 if (sp <= cp + 1 || sp >= cp + sizeof(marker)) 198 return MRK_ERROR; 199 memcpy(marker, cp, sp - cp); 200 marker[sp - cp] = '\0'; 201 if (strcmp(marker, CA_MARKER) == 0) 202 ret = MRK_CA; 203 else if (strcmp(marker, REVOKE_MARKER) == 0) 204 ret = MRK_REVOKE; 205 else 206 return MRK_ERROR; 207 208 /* Skip past marker and any whitespace that follows it */ 209 cp = sp; 210 for (; *cp == ' ' || *cp == '\t'; cp++) 211 ; 212 } 213 *cpp = cp; 214 return ret; 215 } 216 217 struct hostkeys * 218 init_hostkeys(void) 219 { 220 struct hostkeys *ret = xcalloc(1, sizeof(*ret)); 221 222 ret->entries = NULL; 223 return ret; 224 } 225 226 struct load_callback_ctx { 227 const char *host; 228 u_long num_loaded; 229 struct hostkeys *hostkeys; 230 }; 231 232 static int 233 record_hostkey(struct hostkey_foreach_line *l, void *_ctx) 234 { 235 struct load_callback_ctx *ctx = (struct load_callback_ctx *)_ctx; 236 struct hostkeys *hostkeys = ctx->hostkeys; 237 struct hostkey_entry *tmp; 238 239 if (l->status == HKF_STATUS_INVALID) { 240 /* XXX make this verbose() in the future */ 241 debug("%s:%ld: parse error in hostkeys file", 242 l->path, l->linenum); 243 return 0; 244 } 245 246 debug3("%s: found %skey type %s in file %s:%lu", __func__, 247 l->marker == MRK_NONE ? "" : 248 (l->marker == MRK_CA ? "ca " : "revoked "), 249 sshkey_type(l->key), l->path, l->linenum); 250 if ((tmp = recallocarray(hostkeys->entries, hostkeys->num_entries, 251 hostkeys->num_entries + 1, sizeof(*hostkeys->entries))) == NULL) 252 return SSH_ERR_ALLOC_FAIL; 253 hostkeys->entries = tmp; 254 hostkeys->entries[hostkeys->num_entries].host = xstrdup(ctx->host); 255 hostkeys->entries[hostkeys->num_entries].file = xstrdup(l->path); 256 hostkeys->entries[hostkeys->num_entries].line = l->linenum; 257 hostkeys->entries[hostkeys->num_entries].key = l->key; 258 l->key = NULL; /* steal it */ 259 hostkeys->entries[hostkeys->num_entries].marker = l->marker; 260 hostkeys->num_entries++; 261 ctx->num_loaded++; 262 263 return 0; 264 } 265 266 void 267 load_hostkeys(struct hostkeys *hostkeys, const char *host, const char *path) 268 { 269 int r; 270 struct load_callback_ctx ctx; 271 272 ctx.host = host; 273 ctx.num_loaded = 0; 274 ctx.hostkeys = hostkeys; 275 276 if ((r = hostkeys_foreach(path, record_hostkey, &ctx, host, NULL, 277 HKF_WANT_MATCH|HKF_WANT_PARSE_KEY)) != 0) { 278 if (r != SSH_ERR_SYSTEM_ERROR && errno != ENOENT) 279 debug("%s: hostkeys_foreach failed for %s: %s", 280 __func__, path, ssh_err(r)); 281 } 282 if (ctx.num_loaded != 0) 283 debug3("%s: loaded %lu keys from %s", __func__, 284 ctx.num_loaded, host); 285 } 286 287 void 288 free_hostkeys(struct hostkeys *hostkeys) 289 { 290 u_int i; 291 292 for (i = 0; i < hostkeys->num_entries; i++) { 293 free(hostkeys->entries[i].host); 294 free(hostkeys->entries[i].file); 295 sshkey_free(hostkeys->entries[i].key); 296 explicit_bzero(hostkeys->entries + i, sizeof(*hostkeys->entries)); 297 } 298 free(hostkeys->entries); 299 freezero(hostkeys, sizeof(*hostkeys)); 300 } 301 302 static int 303 check_key_not_revoked(struct hostkeys *hostkeys, struct sshkey *k) 304 { 305 int is_cert = sshkey_is_cert(k); 306 u_int i; 307 308 for (i = 0; i < hostkeys->num_entries; i++) { 309 if (hostkeys->entries[i].marker != MRK_REVOKE) 310 continue; 311 if (sshkey_equal_public(k, hostkeys->entries[i].key)) 312 return -1; 313 if (is_cert && 314 sshkey_equal_public(k->cert->signature_key, 315 hostkeys->entries[i].key)) 316 return -1; 317 } 318 return 0; 319 } 320 321 /* 322 * Match keys against a specified key, or look one up by key type. 323 * 324 * If looking for a keytype (key == NULL) and one is found then return 325 * HOST_FOUND, otherwise HOST_NEW. 326 * 327 * If looking for a key (key != NULL): 328 * 1. If the key is a cert and a matching CA is found, return HOST_OK 329 * 2. If the key is not a cert and a matching key is found, return HOST_OK 330 * 3. If no key matches but a key with a different type is found, then 331 * return HOST_CHANGED 332 * 4. If no matching keys are found, then return HOST_NEW. 333 * 334 * Finally, check any found key is not revoked. 335 */ 336 static HostStatus 337 check_hostkeys_by_key_or_type(struct hostkeys *hostkeys, 338 struct sshkey *k, int keytype, const struct hostkey_entry **found) 339 { 340 u_int i; 341 HostStatus end_return = HOST_NEW; 342 int want_cert = sshkey_is_cert(k); 343 HostkeyMarker want_marker = want_cert ? MRK_CA : MRK_NONE; 344 345 if (found != NULL) 346 *found = NULL; 347 348 for (i = 0; i < hostkeys->num_entries; i++) { 349 if (hostkeys->entries[i].marker != want_marker) 350 continue; 351 if (k == NULL) { 352 if (hostkeys->entries[i].key->type != keytype) 353 continue; 354 end_return = HOST_FOUND; 355 if (found != NULL) 356 *found = hostkeys->entries + i; 357 k = hostkeys->entries[i].key; 358 break; 359 } 360 if (want_cert) { 361 if (sshkey_equal_public(k->cert->signature_key, 362 hostkeys->entries[i].key)) { 363 /* A matching CA exists */ 364 end_return = HOST_OK; 365 if (found != NULL) 366 *found = hostkeys->entries + i; 367 break; 368 } 369 } else { 370 if (sshkey_equal(k, hostkeys->entries[i].key)) { 371 end_return = HOST_OK; 372 if (found != NULL) 373 *found = hostkeys->entries + i; 374 break; 375 } 376 /* A non-maching key exists */ 377 end_return = HOST_CHANGED; 378 if (found != NULL) 379 *found = hostkeys->entries + i; 380 } 381 } 382 if (check_key_not_revoked(hostkeys, k) != 0) { 383 end_return = HOST_REVOKED; 384 if (found != NULL) 385 *found = NULL; 386 } 387 return end_return; 388 } 389 390 HostStatus 391 check_key_in_hostkeys(struct hostkeys *hostkeys, struct sshkey *key, 392 const struct hostkey_entry **found) 393 { 394 if (key == NULL) 395 fatal("no key to look up"); 396 return check_hostkeys_by_key_or_type(hostkeys, key, 0, found); 397 } 398 399 int 400 lookup_key_in_hostkeys_by_type(struct hostkeys *hostkeys, int keytype, 401 const struct hostkey_entry **found) 402 { 403 return (check_hostkeys_by_key_or_type(hostkeys, NULL, keytype, 404 found) == HOST_FOUND); 405 } 406 407 static int 408 write_host_entry(FILE *f, const char *host, const char *ip, 409 const struct sshkey *key, int store_hash) 410 { 411 int r, success = 0; 412 char *hashed_host = NULL, *lhost; 413 414 lhost = xstrdup(host); 415 lowercase(lhost); 416 417 if (store_hash) { 418 if ((hashed_host = host_hash(lhost, NULL, 0)) == NULL) { 419 error("%s: host_hash failed", __func__); 420 free(lhost); 421 return 0; 422 } 423 fprintf(f, "%s ", hashed_host); 424 } else if (ip != NULL) 425 fprintf(f, "%s,%s ", lhost, ip); 426 else { 427 fprintf(f, "%s ", lhost); 428 } 429 free(lhost); 430 if ((r = sshkey_write(key, f)) == 0) 431 success = 1; 432 else 433 error("%s: sshkey_write failed: %s", __func__, ssh_err(r)); 434 fputc('\n', f); 435 return success; 436 } 437 438 /* 439 * Appends an entry to the host file. Returns false if the entry could not 440 * be appended. 441 */ 442 int 443 add_host_to_hostfile(const char *filename, const char *host, 444 const struct sshkey *key, int store_hash) 445 { 446 FILE *f; 447 int success; 448 449 if (key == NULL) 450 return 1; /* XXX ? */ 451 f = fopen(filename, "a"); 452 if (!f) 453 return 0; 454 success = write_host_entry(f, host, NULL, key, store_hash); 455 fclose(f); 456 return success; 457 } 458 459 struct host_delete_ctx { 460 FILE *out; 461 int quiet; 462 const char *host; 463 int *skip_keys; /* XXX split for host/ip? might want to ensure both */ 464 struct sshkey * const *keys; 465 size_t nkeys; 466 int modified; 467 }; 468 469 static int 470 host_delete(struct hostkey_foreach_line *l, void *_ctx) 471 { 472 struct host_delete_ctx *ctx = (struct host_delete_ctx *)_ctx; 473 int loglevel = ctx->quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE; 474 size_t i; 475 476 if (l->status == HKF_STATUS_MATCHED) { 477 if (l->marker != MRK_NONE) { 478 /* Don't remove CA and revocation lines */ 479 fprintf(ctx->out, "%s\n", l->line); 480 return 0; 481 } 482 483 /* 484 * If this line contains one of the keys that we will be 485 * adding later, then don't change it and mark the key for 486 * skipping. 487 */ 488 for (i = 0; i < ctx->nkeys; i++) { 489 if (sshkey_equal(ctx->keys[i], l->key)) { 490 ctx->skip_keys[i] = 1; 491 fprintf(ctx->out, "%s\n", l->line); 492 debug3("%s: %s key already at %s:%ld", __func__, 493 sshkey_type(l->key), l->path, l->linenum); 494 return 0; 495 } 496 } 497 498 /* 499 * Hostname matches and has no CA/revoke marker, delete it 500 * by *not* writing the line to ctx->out. 501 */ 502 do_log2(loglevel, "%s%s%s:%ld: Removed %s key for host %s", 503 ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "", 504 l->path, l->linenum, sshkey_type(l->key), ctx->host); 505 ctx->modified = 1; 506 return 0; 507 } 508 /* Retain non-matching hosts and invalid lines when deleting */ 509 if (l->status == HKF_STATUS_INVALID) { 510 do_log2(loglevel, "%s%s%s:%ld: invalid known_hosts entry", 511 ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "", 512 l->path, l->linenum); 513 } 514 fprintf(ctx->out, "%s\n", l->line); 515 return 0; 516 } 517 518 int 519 hostfile_replace_entries(const char *filename, const char *host, const char *ip, 520 struct sshkey **keys, size_t nkeys, int store_hash, int quiet, int hash_alg) 521 { 522 int r, fd, oerrno = 0; 523 int loglevel = quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE; 524 struct host_delete_ctx ctx; 525 char *fp, *temp = NULL, *back = NULL; 526 mode_t omask; 527 size_t i; 528 529 omask = umask(077); 530 531 memset(&ctx, 0, sizeof(ctx)); 532 ctx.host = host; 533 ctx.quiet = quiet; 534 if ((ctx.skip_keys = calloc(nkeys, sizeof(*ctx.skip_keys))) == NULL) 535 return SSH_ERR_ALLOC_FAIL; 536 ctx.keys = keys; 537 ctx.nkeys = nkeys; 538 ctx.modified = 0; 539 540 /* 541 * Prepare temporary file for in-place deletion. 542 */ 543 if ((r = asprintf(&temp, "%s.XXXXXXXXXXX", filename)) == -1 || 544 (r = asprintf(&back, "%s.old", filename)) == -1) { 545 r = SSH_ERR_ALLOC_FAIL; 546 goto fail; 547 } 548 549 if ((fd = mkstemp(temp)) == -1) { 550 oerrno = errno; 551 error("%s: mkstemp: %s", __func__, strerror(oerrno)); 552 r = SSH_ERR_SYSTEM_ERROR; 553 goto fail; 554 } 555 if ((ctx.out = fdopen(fd, "w")) == NULL) { 556 oerrno = errno; 557 close(fd); 558 error("%s: fdopen: %s", __func__, strerror(oerrno)); 559 r = SSH_ERR_SYSTEM_ERROR; 560 goto fail; 561 } 562 563 /* Remove all entries for the specified host from the file */ 564 if ((r = hostkeys_foreach(filename, host_delete, &ctx, host, ip, 565 HKF_WANT_PARSE_KEY)) != 0) { 566 oerrno = errno; 567 error("%s: hostkeys_foreach failed: %s", __func__, ssh_err(r)); 568 goto fail; 569 } 570 571 /* Add the requested keys */ 572 for (i = 0; i < nkeys; i++) { 573 if (ctx.skip_keys[i]) 574 continue; 575 if ((fp = sshkey_fingerprint(keys[i], hash_alg, 576 SSH_FP_DEFAULT)) == NULL) { 577 r = SSH_ERR_ALLOC_FAIL; 578 goto fail; 579 } 580 do_log2(loglevel, "%s%sAdding new key for %s to %s: %s %s", 581 quiet ? __func__ : "", quiet ? ": " : "", host, filename, 582 sshkey_ssh_name(keys[i]), fp); 583 free(fp); 584 if (!write_host_entry(ctx.out, host, ip, keys[i], store_hash)) { 585 r = SSH_ERR_INTERNAL_ERROR; 586 goto fail; 587 } 588 ctx.modified = 1; 589 } 590 fclose(ctx.out); 591 ctx.out = NULL; 592 593 if (ctx.modified) { 594 /* Backup the original file and replace it with the temporary */ 595 if (unlink(back) == -1 && errno != ENOENT) { 596 oerrno = errno; 597 error("%s: unlink %.100s: %s", __func__, 598 back, strerror(errno)); 599 r = SSH_ERR_SYSTEM_ERROR; 600 goto fail; 601 } 602 if (link(filename, back) == -1) { 603 oerrno = errno; 604 error("%s: link %.100s to %.100s: %s", __func__, 605 filename, back, strerror(errno)); 606 r = SSH_ERR_SYSTEM_ERROR; 607 goto fail; 608 } 609 if (rename(temp, filename) == -1) { 610 oerrno = errno; 611 error("%s: rename \"%s\" to \"%s\": %s", __func__, 612 temp, filename, strerror(errno)); 613 r = SSH_ERR_SYSTEM_ERROR; 614 goto fail; 615 } 616 } else { 617 /* No changes made; just delete the temporary file */ 618 if (unlink(temp) != 0) 619 error("%s: unlink \"%s\": %s", __func__, 620 temp, strerror(errno)); 621 } 622 623 /* success */ 624 r = 0; 625 fail: 626 if (temp != NULL && r != 0) 627 unlink(temp); 628 free(temp); 629 free(back); 630 if (ctx.out != NULL) 631 fclose(ctx.out); 632 free(ctx.skip_keys); 633 umask(omask); 634 if (r == SSH_ERR_SYSTEM_ERROR) 635 errno = oerrno; 636 return r; 637 } 638 639 static int 640 match_maybe_hashed(const char *host, const char *names, int *was_hashed) 641 { 642 int hashed = *names == HASH_DELIM; 643 const char *hashed_host; 644 size_t nlen = strlen(names); 645 646 if (was_hashed != NULL) 647 *was_hashed = hashed; 648 if (hashed) { 649 if ((hashed_host = host_hash(host, names, nlen)) == NULL) 650 return -1; 651 return nlen == strlen(hashed_host) && 652 strncmp(hashed_host, names, nlen) == 0; 653 } 654 return match_hostname(host, names) == 1; 655 } 656 657 int 658 hostkeys_foreach(const char *path, hostkeys_foreach_fn *callback, void *ctx, 659 const char *host, const char *ip, u_int options) 660 { 661 FILE *f; 662 char *line = NULL, ktype[128]; 663 u_long linenum = 0; 664 char *cp, *cp2; 665 u_int kbits; 666 int hashed; 667 int s, r = 0; 668 struct hostkey_foreach_line lineinfo; 669 size_t linesize = 0, l; 670 671 memset(&lineinfo, 0, sizeof(lineinfo)); 672 if (host == NULL && (options & HKF_WANT_MATCH) != 0) 673 return SSH_ERR_INVALID_ARGUMENT; 674 if ((f = fopen(path, "r")) == NULL) 675 return SSH_ERR_SYSTEM_ERROR; 676 677 debug3("%s: reading file \"%s\"", __func__, path); 678 while (getline(&line, &linesize, f) != -1) { 679 linenum++; 680 line[strcspn(line, "\n")] = '\0'; 681 682 free(lineinfo.line); 683 sshkey_free(lineinfo.key); 684 memset(&lineinfo, 0, sizeof(lineinfo)); 685 lineinfo.path = path; 686 lineinfo.linenum = linenum; 687 lineinfo.line = xstrdup(line); 688 lineinfo.marker = MRK_NONE; 689 lineinfo.status = HKF_STATUS_OK; 690 lineinfo.keytype = KEY_UNSPEC; 691 692 /* Skip any leading whitespace, comments and empty lines. */ 693 for (cp = line; *cp == ' ' || *cp == '\t'; cp++) 694 ; 695 if (!*cp || *cp == '#' || *cp == '\n') { 696 if ((options & HKF_WANT_MATCH) == 0) { 697 lineinfo.status = HKF_STATUS_COMMENT; 698 if ((r = callback(&lineinfo, ctx)) != 0) 699 break; 700 } 701 continue; 702 } 703 704 if ((lineinfo.marker = check_markers(&cp)) == MRK_ERROR) { 705 verbose("%s: invalid marker at %s:%lu", 706 __func__, path, linenum); 707 if ((options & HKF_WANT_MATCH) == 0) 708 goto bad; 709 continue; 710 } 711 712 /* Find the end of the host name portion. */ 713 for (cp2 = cp; *cp2 && *cp2 != ' ' && *cp2 != '\t'; cp2++) 714 ; 715 lineinfo.hosts = cp; 716 *cp2++ = '\0'; 717 718 /* Check if the host name matches. */ 719 if (host != NULL) { 720 if ((s = match_maybe_hashed(host, lineinfo.hosts, 721 &hashed)) == -1) { 722 debug2("%s: %s:%ld: bad host hash \"%.32s\"", 723 __func__, path, linenum, lineinfo.hosts); 724 goto bad; 725 } 726 if (s == 1) { 727 lineinfo.status = HKF_STATUS_MATCHED; 728 lineinfo.match |= HKF_MATCH_HOST | 729 (hashed ? HKF_MATCH_HOST_HASHED : 0); 730 } 731 /* Try matching IP address if supplied */ 732 if (ip != NULL) { 733 if ((s = match_maybe_hashed(ip, lineinfo.hosts, 734 &hashed)) == -1) { 735 debug2("%s: %s:%ld: bad ip hash " 736 "\"%.32s\"", __func__, path, 737 linenum, lineinfo.hosts); 738 goto bad; 739 } 740 if (s == 1) { 741 lineinfo.status = HKF_STATUS_MATCHED; 742 lineinfo.match |= HKF_MATCH_IP | 743 (hashed ? HKF_MATCH_IP_HASHED : 0); 744 } 745 } 746 /* 747 * Skip this line if host matching requested and 748 * neither host nor address matched. 749 */ 750 if ((options & HKF_WANT_MATCH) != 0 && 751 lineinfo.status != HKF_STATUS_MATCHED) 752 continue; 753 } 754 755 /* Got a match. Skip host name and any following whitespace */ 756 for (; *cp2 == ' ' || *cp2 == '\t'; cp2++) 757 ; 758 if (*cp2 == '\0' || *cp2 == '#') { 759 debug2("%s:%ld: truncated before key type", 760 path, linenum); 761 goto bad; 762 } 763 lineinfo.rawkey = cp = cp2; 764 765 if ((options & HKF_WANT_PARSE_KEY) != 0) { 766 /* 767 * Extract the key from the line. This will skip 768 * any leading whitespace. Ignore badly formatted 769 * lines. 770 */ 771 if ((lineinfo.key = sshkey_new(KEY_UNSPEC)) == NULL) { 772 error("%s: sshkey_new failed", __func__); 773 r = SSH_ERR_ALLOC_FAIL; 774 break; 775 } 776 if (!hostfile_read_key(&cp, &kbits, lineinfo.key)) { 777 goto bad; 778 } 779 lineinfo.keytype = lineinfo.key->type; 780 lineinfo.comment = cp; 781 } else { 782 /* Extract and parse key type */ 783 l = strcspn(lineinfo.rawkey, " \t"); 784 if (l <= 1 || l >= sizeof(ktype) || 785 lineinfo.rawkey[l] == '\0') 786 goto bad; 787 memcpy(ktype, lineinfo.rawkey, l); 788 ktype[l] = '\0'; 789 lineinfo.keytype = sshkey_type_from_name(ktype); 790 791 /* 792 * Assume legacy RSA1 if the first component is a short 793 * decimal number. 794 */ 795 if (lineinfo.keytype == KEY_UNSPEC && l < 8 && 796 strspn(ktype, "0123456789") == l) 797 goto bad; 798 799 /* 800 * Check that something other than whitespace follows 801 * the key type. This won't catch all corruption, but 802 * it does catch trivial truncation. 803 */ 804 cp2 += l; /* Skip past key type */ 805 for (; *cp2 == ' ' || *cp2 == '\t'; cp2++) 806 ; 807 if (*cp2 == '\0' || *cp2 == '#') { 808 debug2("%s:%ld: truncated after key type", 809 path, linenum); 810 lineinfo.keytype = KEY_UNSPEC; 811 } 812 if (lineinfo.keytype == KEY_UNSPEC) { 813 bad: 814 sshkey_free(lineinfo.key); 815 lineinfo.key = NULL; 816 lineinfo.status = HKF_STATUS_INVALID; 817 if ((r = callback(&lineinfo, ctx)) != 0) 818 break; 819 continue; 820 } 821 } 822 if ((r = callback(&lineinfo, ctx)) != 0) 823 break; 824 } 825 sshkey_free(lineinfo.key); 826 free(lineinfo.line); 827 free(line); 828 fclose(f); 829 return r; 830 } 831