1 /* $OpenBSD: hostfile.c,v 1.79 2020/03/06 18:25:12 markus 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 "ssherr.h" 61 #include "digest.h" 62 #include "hmac.h" 63 64 struct hostkeys { 65 struct hostkey_entry *entries; 66 u_int num_entries; 67 }; 68 69 /* XXX hmac is too easy to dictionary attack; use bcrypt? */ 70 71 static int 72 extract_salt(const char *s, u_int l, u_char *salt, size_t salt_len) 73 { 74 char *p, *b64salt; 75 u_int b64len; 76 int ret; 77 78 if (l < sizeof(HASH_MAGIC) - 1) { 79 debug2("extract_salt: string too short"); 80 return (-1); 81 } 82 if (strncmp(s, HASH_MAGIC, sizeof(HASH_MAGIC) - 1) != 0) { 83 debug2("extract_salt: invalid magic identifier"); 84 return (-1); 85 } 86 s += sizeof(HASH_MAGIC) - 1; 87 l -= sizeof(HASH_MAGIC) - 1; 88 if ((p = memchr(s, HASH_DELIM, l)) == NULL) { 89 debug2("extract_salt: missing salt termination character"); 90 return (-1); 91 } 92 93 b64len = p - s; 94 /* Sanity check */ 95 if (b64len == 0 || b64len > 1024) { 96 debug2("extract_salt: bad encoded salt length %u", b64len); 97 return (-1); 98 } 99 b64salt = xmalloc(1 + b64len); 100 memcpy(b64salt, s, b64len); 101 b64salt[b64len] = '\0'; 102 103 ret = __b64_pton(b64salt, salt, salt_len); 104 free(b64salt); 105 if (ret == -1) { 106 debug2("extract_salt: salt decode error"); 107 return (-1); 108 } 109 if (ret != (int)ssh_hmac_bytes(SSH_DIGEST_SHA1)) { 110 debug2("extract_salt: expected salt len %zd, got %d", 111 ssh_hmac_bytes(SSH_DIGEST_SHA1), ret); 112 return (-1); 113 } 114 115 return (0); 116 } 117 118 char * 119 host_hash(const char *host, const char *name_from_hostfile, u_int src_len) 120 { 121 struct ssh_hmac_ctx *ctx; 122 u_char salt[256], result[256]; 123 char uu_salt[512], uu_result[512]; 124 static char encoded[1024]; 125 u_int len; 126 127 len = ssh_digest_bytes(SSH_DIGEST_SHA1); 128 129 if (name_from_hostfile == NULL) { 130 /* Create new salt */ 131 arc4random_buf(salt, len); 132 } else { 133 /* Extract salt from known host entry */ 134 if (extract_salt(name_from_hostfile, src_len, salt, 135 sizeof(salt)) == -1) 136 return (NULL); 137 } 138 139 if ((ctx = ssh_hmac_start(SSH_DIGEST_SHA1)) == NULL || 140 ssh_hmac_init(ctx, salt, len) < 0 || 141 ssh_hmac_update(ctx, host, strlen(host)) < 0 || 142 ssh_hmac_final(ctx, result, sizeof(result))) 143 fatal("%s: ssh_hmac failed", __func__); 144 ssh_hmac_free(ctx); 145 146 if (__b64_ntop(salt, len, uu_salt, sizeof(uu_salt)) == -1 || 147 __b64_ntop(result, len, uu_result, sizeof(uu_result)) == -1) 148 fatal("%s: __b64_ntop failed", __func__); 149 150 snprintf(encoded, sizeof(encoded), "%s%s%c%s", HASH_MAGIC, uu_salt, 151 HASH_DELIM, uu_result); 152 153 return (encoded); 154 } 155 156 /* 157 * Parses an RSA (number of bits, e, n) or DSA key from a string. Moves the 158 * pointer over the key. Skips any whitespace at the beginning and at end. 159 */ 160 161 int 162 hostfile_read_key(char **cpp, u_int *bitsp, struct sshkey *ret) 163 { 164 char *cp; 165 166 /* Skip leading whitespace. */ 167 for (cp = *cpp; *cp == ' ' || *cp == '\t'; cp++) 168 ; 169 170 if (sshkey_read(ret, &cp) != 0) 171 return 0; 172 173 /* Skip trailing whitespace. */ 174 for (; *cp == ' ' || *cp == '\t'; cp++) 175 ; 176 177 /* Return results. */ 178 *cpp = cp; 179 if (bitsp != NULL) 180 *bitsp = sshkey_size(ret); 181 return 1; 182 } 183 184 static HostkeyMarker 185 check_markers(char **cpp) 186 { 187 char marker[32], *sp, *cp = *cpp; 188 int ret = MRK_NONE; 189 190 while (*cp == '@') { 191 /* Only one marker is allowed */ 192 if (ret != MRK_NONE) 193 return MRK_ERROR; 194 /* Markers are terminated by whitespace */ 195 if ((sp = strchr(cp, ' ')) == NULL && 196 (sp = strchr(cp, '\t')) == NULL) 197 return MRK_ERROR; 198 /* Extract marker for comparison */ 199 if (sp <= cp + 1 || sp >= cp + sizeof(marker)) 200 return MRK_ERROR; 201 memcpy(marker, cp, sp - cp); 202 marker[sp - cp] = '\0'; 203 if (strcmp(marker, CA_MARKER) == 0) 204 ret = MRK_CA; 205 else if (strcmp(marker, REVOKE_MARKER) == 0) 206 ret = MRK_REVOKE; 207 else 208 return MRK_ERROR; 209 210 /* Skip past marker and any whitespace that follows it */ 211 cp = sp; 212 for (; *cp == ' ' || *cp == '\t'; cp++) 213 ; 214 } 215 *cpp = cp; 216 return ret; 217 } 218 219 struct hostkeys * 220 init_hostkeys(void) 221 { 222 struct hostkeys *ret = xcalloc(1, sizeof(*ret)); 223 224 ret->entries = NULL; 225 return ret; 226 } 227 228 struct load_callback_ctx { 229 const char *host; 230 u_long num_loaded; 231 struct hostkeys *hostkeys; 232 }; 233 234 static int 235 record_hostkey(struct hostkey_foreach_line *l, void *_ctx) 236 { 237 struct load_callback_ctx *ctx = (struct load_callback_ctx *)_ctx; 238 struct hostkeys *hostkeys = ctx->hostkeys; 239 struct hostkey_entry *tmp; 240 241 if (l->status == HKF_STATUS_INVALID) { 242 /* XXX make this verbose() in the future */ 243 debug("%s:%ld: parse error in hostkeys file", 244 l->path, l->linenum); 245 return 0; 246 } 247 248 debug3("%s: found %skey type %s in file %s:%lu", __func__, 249 l->marker == MRK_NONE ? "" : 250 (l->marker == MRK_CA ? "ca " : "revoked "), 251 sshkey_type(l->key), l->path, l->linenum); 252 if ((tmp = recallocarray(hostkeys->entries, hostkeys->num_entries, 253 hostkeys->num_entries + 1, sizeof(*hostkeys->entries))) == NULL) 254 return SSH_ERR_ALLOC_FAIL; 255 hostkeys->entries = tmp; 256 hostkeys->entries[hostkeys->num_entries].host = xstrdup(ctx->host); 257 hostkeys->entries[hostkeys->num_entries].file = xstrdup(l->path); 258 hostkeys->entries[hostkeys->num_entries].line = l->linenum; 259 hostkeys->entries[hostkeys->num_entries].key = l->key; 260 l->key = NULL; /* steal it */ 261 hostkeys->entries[hostkeys->num_entries].marker = l->marker; 262 hostkeys->num_entries++; 263 ctx->num_loaded++; 264 265 return 0; 266 } 267 268 void 269 load_hostkeys(struct hostkeys *hostkeys, const char *host, const char *path) 270 { 271 int r; 272 struct load_callback_ctx ctx; 273 274 ctx.host = host; 275 ctx.num_loaded = 0; 276 ctx.hostkeys = hostkeys; 277 278 if ((r = hostkeys_foreach(path, record_hostkey, &ctx, host, NULL, 279 HKF_WANT_MATCH|HKF_WANT_PARSE_KEY)) != 0) { 280 if (r != SSH_ERR_SYSTEM_ERROR && errno != ENOENT) 281 debug("%s: hostkeys_foreach failed for %s: %s", 282 __func__, path, ssh_err(r)); 283 } 284 if (ctx.num_loaded != 0) 285 debug3("%s: loaded %lu keys from %s", __func__, 286 ctx.num_loaded, host); 287 } 288 289 void 290 free_hostkeys(struct hostkeys *hostkeys) 291 { 292 u_int i; 293 294 for (i = 0; i < hostkeys->num_entries; i++) { 295 free(hostkeys->entries[i].host); 296 free(hostkeys->entries[i].file); 297 sshkey_free(hostkeys->entries[i].key); 298 explicit_bzero(hostkeys->entries + i, sizeof(*hostkeys->entries)); 299 } 300 free(hostkeys->entries); 301 freezero(hostkeys, sizeof(*hostkeys)); 302 } 303 304 static int 305 check_key_not_revoked(struct hostkeys *hostkeys, struct sshkey *k) 306 { 307 int is_cert = sshkey_is_cert(k); 308 u_int i; 309 310 for (i = 0; i < hostkeys->num_entries; i++) { 311 if (hostkeys->entries[i].marker != MRK_REVOKE) 312 continue; 313 if (sshkey_equal_public(k, hostkeys->entries[i].key)) 314 return -1; 315 if (is_cert && k != NULL && 316 sshkey_equal_public(k->cert->signature_key, 317 hostkeys->entries[i].key)) 318 return -1; 319 } 320 return 0; 321 } 322 323 /* 324 * Match keys against a specified key, or look one up by key type. 325 * 326 * If looking for a keytype (key == NULL) and one is found then return 327 * HOST_FOUND, otherwise HOST_NEW. 328 * 329 * If looking for a key (key != NULL): 330 * 1. If the key is a cert and a matching CA is found, return HOST_OK 331 * 2. If the key is not a cert and a matching key is found, return HOST_OK 332 * 3. If no key matches but a key with a different type is found, then 333 * return HOST_CHANGED 334 * 4. If no matching keys are found, then return HOST_NEW. 335 * 336 * Finally, check any found key is not revoked. 337 */ 338 static HostStatus 339 check_hostkeys_by_key_or_type(struct hostkeys *hostkeys, 340 struct sshkey *k, int keytype, const struct hostkey_entry **found) 341 { 342 u_int i; 343 HostStatus end_return = HOST_NEW; 344 int want_cert = sshkey_is_cert(k); 345 HostkeyMarker want_marker = want_cert ? MRK_CA : MRK_NONE; 346 347 if (found != NULL) 348 *found = NULL; 349 350 for (i = 0; i < hostkeys->num_entries; i++) { 351 if (hostkeys->entries[i].marker != want_marker) 352 continue; 353 if (k == NULL) { 354 if (hostkeys->entries[i].key->type != keytype) 355 continue; 356 end_return = HOST_FOUND; 357 if (found != NULL) 358 *found = hostkeys->entries + i; 359 k = hostkeys->entries[i].key; 360 break; 361 } 362 if (want_cert) { 363 if (sshkey_equal_public(k->cert->signature_key, 364 hostkeys->entries[i].key)) { 365 /* A matching CA exists */ 366 end_return = HOST_OK; 367 if (found != NULL) 368 *found = hostkeys->entries + i; 369 break; 370 } 371 } else { 372 if (sshkey_equal(k, hostkeys->entries[i].key)) { 373 end_return = HOST_OK; 374 if (found != NULL) 375 *found = hostkeys->entries + i; 376 break; 377 } 378 /* A non-maching key exists */ 379 end_return = HOST_CHANGED; 380 if (found != NULL) 381 *found = hostkeys->entries + i; 382 } 383 } 384 if (check_key_not_revoked(hostkeys, k) != 0) { 385 end_return = HOST_REVOKED; 386 if (found != NULL) 387 *found = NULL; 388 } 389 return end_return; 390 } 391 392 HostStatus 393 check_key_in_hostkeys(struct hostkeys *hostkeys, struct sshkey *key, 394 const struct hostkey_entry **found) 395 { 396 if (key == NULL) 397 fatal("no key to look up"); 398 return check_hostkeys_by_key_or_type(hostkeys, key, 0, found); 399 } 400 401 int 402 lookup_key_in_hostkeys_by_type(struct hostkeys *hostkeys, int keytype, 403 const struct hostkey_entry **found) 404 { 405 return (check_hostkeys_by_key_or_type(hostkeys, NULL, keytype, 406 found) == HOST_FOUND); 407 } 408 409 static int 410 write_host_entry(FILE *f, const char *host, const char *ip, 411 const struct sshkey *key, int store_hash) 412 { 413 int r, success = 0; 414 char *hashed_host = NULL, *lhost; 415 416 lhost = xstrdup(host); 417 lowercase(lhost); 418 419 if (store_hash) { 420 if ((hashed_host = host_hash(lhost, NULL, 0)) == NULL) { 421 error("%s: host_hash failed", __func__); 422 free(lhost); 423 return 0; 424 } 425 fprintf(f, "%s ", hashed_host); 426 } else if (ip != NULL) 427 fprintf(f, "%s,%s ", lhost, ip); 428 else { 429 fprintf(f, "%s ", lhost); 430 } 431 free(lhost); 432 if ((r = sshkey_write(key, f)) == 0) 433 success = 1; 434 else 435 error("%s: sshkey_write failed: %s", __func__, ssh_err(r)); 436 fputc('\n', f); 437 return success; 438 } 439 440 /* 441 * Appends an entry to the host file. Returns false if the entry could not 442 * be appended. 443 */ 444 int 445 add_host_to_hostfile(const char *filename, const char *host, 446 const struct sshkey *key, int store_hash) 447 { 448 FILE *f; 449 int success; 450 451 if (key == NULL) 452 return 1; /* XXX ? */ 453 f = fopen(filename, "a"); 454 if (!f) 455 return 0; 456 success = write_host_entry(f, host, NULL, key, store_hash); 457 fclose(f); 458 return success; 459 } 460 461 struct host_delete_ctx { 462 FILE *out; 463 int quiet; 464 const char *host; 465 int *skip_keys; /* XXX split for host/ip? might want to ensure both */ 466 struct sshkey * const *keys; 467 size_t nkeys; 468 int modified; 469 }; 470 471 static int 472 host_delete(struct hostkey_foreach_line *l, void *_ctx) 473 { 474 struct host_delete_ctx *ctx = (struct host_delete_ctx *)_ctx; 475 int loglevel = ctx->quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE; 476 size_t i; 477 478 if (l->status == HKF_STATUS_MATCHED) { 479 if (l->marker != MRK_NONE) { 480 /* Don't remove CA and revocation lines */ 481 fprintf(ctx->out, "%s\n", l->line); 482 return 0; 483 } 484 485 /* 486 * If this line contains one of the keys that we will be 487 * adding later, then don't change it and mark the key for 488 * skipping. 489 */ 490 for (i = 0; i < ctx->nkeys; i++) { 491 if (sshkey_equal(ctx->keys[i], l->key)) { 492 ctx->skip_keys[i] = 1; 493 fprintf(ctx->out, "%s\n", l->line); 494 debug3("%s: %s key already at %s:%ld", __func__, 495 sshkey_type(l->key), l->path, l->linenum); 496 return 0; 497 } 498 } 499 500 /* 501 * Hostname matches and has no CA/revoke marker, delete it 502 * by *not* writing the line to ctx->out. 503 */ 504 do_log2(loglevel, "%s%s%s:%ld: Removed %s key for host %s", 505 ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "", 506 l->path, l->linenum, sshkey_type(l->key), ctx->host); 507 ctx->modified = 1; 508 return 0; 509 } 510 /* Retain non-matching hosts and invalid lines when deleting */ 511 if (l->status == HKF_STATUS_INVALID) { 512 do_log2(loglevel, "%s%s%s:%ld: invalid known_hosts entry", 513 ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "", 514 l->path, l->linenum); 515 } 516 fprintf(ctx->out, "%s\n", l->line); 517 return 0; 518 } 519 520 int 521 hostfile_replace_entries(const char *filename, const char *host, const char *ip, 522 struct sshkey **keys, size_t nkeys, int store_hash, int quiet, int hash_alg) 523 { 524 int r, fd, oerrno = 0; 525 int loglevel = quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE; 526 struct host_delete_ctx ctx; 527 char *fp, *temp = NULL, *back = NULL; 528 mode_t omask; 529 size_t i; 530 531 omask = umask(077); 532 533 memset(&ctx, 0, sizeof(ctx)); 534 ctx.host = host; 535 ctx.quiet = quiet; 536 if ((ctx.skip_keys = calloc(nkeys, sizeof(*ctx.skip_keys))) == NULL) 537 return SSH_ERR_ALLOC_FAIL; 538 ctx.keys = keys; 539 ctx.nkeys = nkeys; 540 ctx.modified = 0; 541 542 /* 543 * Prepare temporary file for in-place deletion. 544 */ 545 if ((r = asprintf(&temp, "%s.XXXXXXXXXXX", filename)) == -1 || 546 (r = asprintf(&back, "%s.old", filename)) == -1) { 547 r = SSH_ERR_ALLOC_FAIL; 548 goto fail; 549 } 550 551 if ((fd = mkstemp(temp)) == -1) { 552 oerrno = errno; 553 error("%s: mkstemp: %s", __func__, strerror(oerrno)); 554 r = SSH_ERR_SYSTEM_ERROR; 555 goto fail; 556 } 557 if ((ctx.out = fdopen(fd, "w")) == NULL) { 558 oerrno = errno; 559 close(fd); 560 error("%s: fdopen: %s", __func__, strerror(oerrno)); 561 r = SSH_ERR_SYSTEM_ERROR; 562 goto fail; 563 } 564 565 /* Remove all entries for the specified host from the file */ 566 if ((r = hostkeys_foreach(filename, host_delete, &ctx, host, ip, 567 HKF_WANT_PARSE_KEY)) != 0) { 568 oerrno = errno; 569 error("%s: hostkeys_foreach failed: %s", __func__, ssh_err(r)); 570 goto fail; 571 } 572 573 /* Add the requested keys */ 574 for (i = 0; i < nkeys; i++) { 575 if (ctx.skip_keys[i]) 576 continue; 577 if ((fp = sshkey_fingerprint(keys[i], hash_alg, 578 SSH_FP_DEFAULT)) == NULL) { 579 r = SSH_ERR_ALLOC_FAIL; 580 goto fail; 581 } 582 do_log2(loglevel, "%s%sAdding new key for %s to %s: %s %s", 583 quiet ? __func__ : "", quiet ? ": " : "", host, filename, 584 sshkey_ssh_name(keys[i]), fp); 585 free(fp); 586 if (!write_host_entry(ctx.out, host, ip, keys[i], store_hash)) { 587 r = SSH_ERR_INTERNAL_ERROR; 588 goto fail; 589 } 590 ctx.modified = 1; 591 } 592 fclose(ctx.out); 593 ctx.out = NULL; 594 595 if (ctx.modified) { 596 /* Backup the original file and replace it with the temporary */ 597 if (unlink(back) == -1 && errno != ENOENT) { 598 oerrno = errno; 599 error("%s: unlink %.100s: %s", __func__, 600 back, strerror(errno)); 601 r = SSH_ERR_SYSTEM_ERROR; 602 goto fail; 603 } 604 if (link(filename, back) == -1) { 605 oerrno = errno; 606 error("%s: link %.100s to %.100s: %s", __func__, 607 filename, back, strerror(errno)); 608 r = SSH_ERR_SYSTEM_ERROR; 609 goto fail; 610 } 611 if (rename(temp, filename) == -1) { 612 oerrno = errno; 613 error("%s: rename \"%s\" to \"%s\": %s", __func__, 614 temp, filename, strerror(errno)); 615 r = SSH_ERR_SYSTEM_ERROR; 616 goto fail; 617 } 618 } else { 619 /* No changes made; just delete the temporary file */ 620 if (unlink(temp) != 0) 621 error("%s: unlink \"%s\": %s", __func__, 622 temp, strerror(errno)); 623 } 624 625 /* success */ 626 r = 0; 627 fail: 628 if (temp != NULL && r != 0) 629 unlink(temp); 630 free(temp); 631 free(back); 632 if (ctx.out != NULL) 633 fclose(ctx.out); 634 free(ctx.skip_keys); 635 umask(omask); 636 if (r == SSH_ERR_SYSTEM_ERROR) 637 errno = oerrno; 638 return r; 639 } 640 641 static int 642 match_maybe_hashed(const char *host, const char *names, int *was_hashed) 643 { 644 int hashed = *names == HASH_DELIM; 645 const char *hashed_host; 646 size_t nlen = strlen(names); 647 648 if (was_hashed != NULL) 649 *was_hashed = hashed; 650 if (hashed) { 651 if ((hashed_host = host_hash(host, names, nlen)) == NULL) 652 return -1; 653 return nlen == strlen(hashed_host) && 654 strncmp(hashed_host, names, nlen) == 0; 655 } 656 return match_hostname(host, names) == 1; 657 } 658 659 int 660 hostkeys_foreach(const char *path, hostkeys_foreach_fn *callback, void *ctx, 661 const char *host, const char *ip, u_int options) 662 { 663 FILE *f; 664 char *line = NULL, ktype[128]; 665 u_long linenum = 0; 666 char *cp, *cp2; 667 u_int kbits; 668 int hashed; 669 int s, r = 0; 670 struct hostkey_foreach_line lineinfo; 671 size_t linesize = 0, l; 672 673 memset(&lineinfo, 0, sizeof(lineinfo)); 674 if (host == NULL && (options & HKF_WANT_MATCH) != 0) 675 return SSH_ERR_INVALID_ARGUMENT; 676 if ((f = fopen(path, "r")) == NULL) 677 return SSH_ERR_SYSTEM_ERROR; 678 679 debug3("%s: reading file \"%s\"", __func__, path); 680 while (getline(&line, &linesize, f) != -1) { 681 linenum++; 682 line[strcspn(line, "\n")] = '\0'; 683 684 free(lineinfo.line); 685 sshkey_free(lineinfo.key); 686 memset(&lineinfo, 0, sizeof(lineinfo)); 687 lineinfo.path = path; 688 lineinfo.linenum = linenum; 689 lineinfo.line = xstrdup(line); 690 lineinfo.marker = MRK_NONE; 691 lineinfo.status = HKF_STATUS_OK; 692 lineinfo.keytype = KEY_UNSPEC; 693 694 /* Skip any leading whitespace, comments and empty lines. */ 695 for (cp = line; *cp == ' ' || *cp == '\t'; cp++) 696 ; 697 if (!*cp || *cp == '#' || *cp == '\n') { 698 if ((options & HKF_WANT_MATCH) == 0) { 699 lineinfo.status = HKF_STATUS_COMMENT; 700 if ((r = callback(&lineinfo, ctx)) != 0) 701 break; 702 } 703 continue; 704 } 705 706 if ((lineinfo.marker = check_markers(&cp)) == MRK_ERROR) { 707 verbose("%s: invalid marker at %s:%lu", 708 __func__, path, linenum); 709 if ((options & HKF_WANT_MATCH) == 0) 710 goto bad; 711 continue; 712 } 713 714 /* Find the end of the host name portion. */ 715 for (cp2 = cp; *cp2 && *cp2 != ' ' && *cp2 != '\t'; cp2++) 716 ; 717 lineinfo.hosts = cp; 718 *cp2++ = '\0'; 719 720 /* Check if the host name matches. */ 721 if (host != NULL) { 722 if ((s = match_maybe_hashed(host, lineinfo.hosts, 723 &hashed)) == -1) { 724 debug2("%s: %s:%ld: bad host hash \"%.32s\"", 725 __func__, path, linenum, lineinfo.hosts); 726 goto bad; 727 } 728 if (s == 1) { 729 lineinfo.status = HKF_STATUS_MATCHED; 730 lineinfo.match |= HKF_MATCH_HOST | 731 (hashed ? HKF_MATCH_HOST_HASHED : 0); 732 } 733 /* Try matching IP address if supplied */ 734 if (ip != NULL) { 735 if ((s = match_maybe_hashed(ip, lineinfo.hosts, 736 &hashed)) == -1) { 737 debug2("%s: %s:%ld: bad ip hash " 738 "\"%.32s\"", __func__, path, 739 linenum, lineinfo.hosts); 740 goto bad; 741 } 742 if (s == 1) { 743 lineinfo.status = HKF_STATUS_MATCHED; 744 lineinfo.match |= HKF_MATCH_IP | 745 (hashed ? HKF_MATCH_IP_HASHED : 0); 746 } 747 } 748 /* 749 * Skip this line if host matching requested and 750 * neither host nor address matched. 751 */ 752 if ((options & HKF_WANT_MATCH) != 0 && 753 lineinfo.status != HKF_STATUS_MATCHED) 754 continue; 755 } 756 757 /* Got a match. Skip host name and any following whitespace */ 758 for (; *cp2 == ' ' || *cp2 == '\t'; cp2++) 759 ; 760 if (*cp2 == '\0' || *cp2 == '#') { 761 debug2("%s:%ld: truncated before key type", 762 path, linenum); 763 goto bad; 764 } 765 lineinfo.rawkey = cp = cp2; 766 767 if ((options & HKF_WANT_PARSE_KEY) != 0) { 768 /* 769 * Extract the key from the line. This will skip 770 * any leading whitespace. Ignore badly formatted 771 * lines. 772 */ 773 if ((lineinfo.key = sshkey_new(KEY_UNSPEC)) == NULL) { 774 error("%s: sshkey_new failed", __func__); 775 r = SSH_ERR_ALLOC_FAIL; 776 break; 777 } 778 if (!hostfile_read_key(&cp, &kbits, lineinfo.key)) { 779 goto bad; 780 } 781 lineinfo.keytype = lineinfo.key->type; 782 lineinfo.comment = cp; 783 } else { 784 /* Extract and parse key type */ 785 l = strcspn(lineinfo.rawkey, " \t"); 786 if (l <= 1 || l >= sizeof(ktype) || 787 lineinfo.rawkey[l] == '\0') 788 goto bad; 789 memcpy(ktype, lineinfo.rawkey, l); 790 ktype[l] = '\0'; 791 lineinfo.keytype = sshkey_type_from_name(ktype); 792 793 /* 794 * Assume legacy RSA1 if the first component is a short 795 * decimal number. 796 */ 797 if (lineinfo.keytype == KEY_UNSPEC && l < 8 && 798 strspn(ktype, "0123456789") == l) 799 goto bad; 800 801 /* 802 * Check that something other than whitespace follows 803 * the key type. This won't catch all corruption, but 804 * it does catch trivial truncation. 805 */ 806 cp2 += l; /* Skip past key type */ 807 for (; *cp2 == ' ' || *cp2 == '\t'; cp2++) 808 ; 809 if (*cp2 == '\0' || *cp2 == '#') { 810 debug2("%s:%ld: truncated after key type", 811 path, linenum); 812 lineinfo.keytype = KEY_UNSPEC; 813 } 814 if (lineinfo.keytype == KEY_UNSPEC) { 815 bad: 816 sshkey_free(lineinfo.key); 817 lineinfo.key = NULL; 818 lineinfo.status = HKF_STATUS_INVALID; 819 if ((r = callback(&lineinfo, ctx)) != 0) 820 break; 821 continue; 822 } 823 } 824 if ((r = callback(&lineinfo, ctx)) != 0) 825 break; 826 } 827 sshkey_free(lineinfo.key); 828 free(lineinfo.line); 829 free(line); 830 fclose(f); 831 return r; 832 } 833