1 /* $OpenBSD: hostfile.c,v 1.71 2017/05/31 09:15:42 deraadt 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 <stdarg.h> 53 #include <unistd.h> 54 55 #include "xmalloc.h" 56 #include "match.h" 57 #include "sshkey.h" 58 #include "hostfile.h" 59 #include "log.h" 60 #include "misc.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 int r; 167 168 /* Skip leading whitespace. */ 169 for (cp = *cpp; *cp == ' ' || *cp == '\t'; cp++) 170 ; 171 172 if ((r = sshkey_read(ret, &cp)) != 0) 173 return 0; 174 175 /* Skip trailing whitespace. */ 176 for (; *cp == ' ' || *cp == '\t'; cp++) 177 ; 178 179 /* Return results. */ 180 *cpp = cp; 181 if (bitsp != NULL) 182 *bitsp = sshkey_size(ret); 183 return 1; 184 } 185 186 static HostkeyMarker 187 check_markers(char **cpp) 188 { 189 char marker[32], *sp, *cp = *cpp; 190 int ret = MRK_NONE; 191 192 while (*cp == '@') { 193 /* Only one marker is allowed */ 194 if (ret != MRK_NONE) 195 return MRK_ERROR; 196 /* Markers are terminated by whitespace */ 197 if ((sp = strchr(cp, ' ')) == NULL && 198 (sp = strchr(cp, '\t')) == NULL) 199 return MRK_ERROR; 200 /* Extract marker for comparison */ 201 if (sp <= cp + 1 || sp >= cp + sizeof(marker)) 202 return MRK_ERROR; 203 memcpy(marker, cp, sp - cp); 204 marker[sp - cp] = '\0'; 205 if (strcmp(marker, CA_MARKER) == 0) 206 ret = MRK_CA; 207 else if (strcmp(marker, REVOKE_MARKER) == 0) 208 ret = MRK_REVOKE; 209 else 210 return MRK_ERROR; 211 212 /* Skip past marker and any whitespace that follows it */ 213 cp = sp; 214 for (; *cp == ' ' || *cp == '\t'; cp++) 215 ; 216 } 217 *cpp = cp; 218 return ret; 219 } 220 221 struct hostkeys * 222 init_hostkeys(void) 223 { 224 struct hostkeys *ret = xcalloc(1, sizeof(*ret)); 225 226 ret->entries = NULL; 227 return ret; 228 } 229 230 struct load_callback_ctx { 231 const char *host; 232 u_long num_loaded; 233 struct hostkeys *hostkeys; 234 }; 235 236 static int 237 record_hostkey(struct hostkey_foreach_line *l, void *_ctx) 238 { 239 struct load_callback_ctx *ctx = (struct load_callback_ctx *)_ctx; 240 struct hostkeys *hostkeys = ctx->hostkeys; 241 struct hostkey_entry *tmp; 242 243 if (l->status == HKF_STATUS_INVALID) { 244 /* XXX make this verbose() in the future */ 245 debug("%s:%ld: parse error in hostkeys file", 246 l->path, l->linenum); 247 return 0; 248 } 249 250 debug3("%s: found %skey type %s in file %s:%lu", __func__, 251 l->marker == MRK_NONE ? "" : 252 (l->marker == MRK_CA ? "ca " : "revoked "), 253 sshkey_type(l->key), l->path, l->linenum); 254 if ((tmp = recallocarray(hostkeys->entries, hostkeys->num_entries, 255 hostkeys->num_entries + 1, sizeof(*hostkeys->entries))) == NULL) 256 return SSH_ERR_ALLOC_FAIL; 257 hostkeys->entries = tmp; 258 hostkeys->entries[hostkeys->num_entries].host = xstrdup(ctx->host); 259 hostkeys->entries[hostkeys->num_entries].file = xstrdup(l->path); 260 hostkeys->entries[hostkeys->num_entries].line = l->linenum; 261 hostkeys->entries[hostkeys->num_entries].key = l->key; 262 l->key = NULL; /* steal it */ 263 hostkeys->entries[hostkeys->num_entries].marker = l->marker; 264 hostkeys->num_entries++; 265 ctx->num_loaded++; 266 267 return 0; 268 } 269 270 void 271 load_hostkeys(struct hostkeys *hostkeys, const char *host, const char *path) 272 { 273 int r; 274 struct load_callback_ctx ctx; 275 276 ctx.host = host; 277 ctx.num_loaded = 0; 278 ctx.hostkeys = hostkeys; 279 280 if ((r = hostkeys_foreach(path, record_hostkey, &ctx, host, NULL, 281 HKF_WANT_MATCH|HKF_WANT_PARSE_KEY)) != 0) { 282 if (r != SSH_ERR_SYSTEM_ERROR && errno != ENOENT) 283 debug("%s: hostkeys_foreach failed for %s: %s", 284 __func__, path, ssh_err(r)); 285 } 286 if (ctx.num_loaded != 0) 287 debug3("%s: loaded %lu keys from %s", __func__, 288 ctx.num_loaded, host); 289 } 290 291 void 292 free_hostkeys(struct hostkeys *hostkeys) 293 { 294 u_int i; 295 296 for (i = 0; i < hostkeys->num_entries; i++) { 297 free(hostkeys->entries[i].host); 298 free(hostkeys->entries[i].file); 299 sshkey_free(hostkeys->entries[i].key); 300 explicit_bzero(hostkeys->entries + i, sizeof(*hostkeys->entries)); 301 } 302 free(hostkeys->entries); 303 explicit_bzero(hostkeys, sizeof(*hostkeys)); 304 free(hostkeys); 305 } 306 307 static int 308 check_key_not_revoked(struct hostkeys *hostkeys, struct sshkey *k) 309 { 310 int is_cert = sshkey_is_cert(k); 311 u_int i; 312 313 for (i = 0; i < hostkeys->num_entries; i++) { 314 if (hostkeys->entries[i].marker != MRK_REVOKE) 315 continue; 316 if (sshkey_equal_public(k, hostkeys->entries[i].key)) 317 return -1; 318 if (is_cert && 319 sshkey_equal_public(k->cert->signature_key, 320 hostkeys->entries[i].key)) 321 return -1; 322 } 323 return 0; 324 } 325 326 /* 327 * Match keys against a specified key, or look one up by key type. 328 * 329 * If looking for a keytype (key == NULL) and one is found then return 330 * HOST_FOUND, otherwise HOST_NEW. 331 * 332 * If looking for a key (key != NULL): 333 * 1. If the key is a cert and a matching CA is found, return HOST_OK 334 * 2. If the key is not a cert and a matching key is found, return HOST_OK 335 * 3. If no key matches but a key with a different type is found, then 336 * return HOST_CHANGED 337 * 4. If no matching keys are found, then return HOST_NEW. 338 * 339 * Finally, check any found key is not revoked. 340 */ 341 static HostStatus 342 check_hostkeys_by_key_or_type(struct hostkeys *hostkeys, 343 struct sshkey *k, int keytype, const struct hostkey_entry **found) 344 { 345 u_int i; 346 HostStatus end_return = HOST_NEW; 347 int want_cert = sshkey_is_cert(k); 348 HostkeyMarker want_marker = want_cert ? MRK_CA : MRK_NONE; 349 350 if (found != NULL) 351 *found = NULL; 352 353 for (i = 0; i < hostkeys->num_entries; i++) { 354 if (hostkeys->entries[i].marker != want_marker) 355 continue; 356 if (k == NULL) { 357 if (hostkeys->entries[i].key->type != keytype) 358 continue; 359 end_return = HOST_FOUND; 360 if (found != NULL) 361 *found = hostkeys->entries + i; 362 k = hostkeys->entries[i].key; 363 break; 364 } 365 if (want_cert) { 366 if (sshkey_equal_public(k->cert->signature_key, 367 hostkeys->entries[i].key)) { 368 /* A matching CA exists */ 369 end_return = HOST_OK; 370 if (found != NULL) 371 *found = hostkeys->entries + i; 372 break; 373 } 374 } else { 375 if (sshkey_equal(k, hostkeys->entries[i].key)) { 376 end_return = HOST_OK; 377 if (found != NULL) 378 *found = hostkeys->entries + i; 379 break; 380 } 381 /* A non-maching key exists */ 382 end_return = HOST_CHANGED; 383 if (found != NULL) 384 *found = hostkeys->entries + i; 385 } 386 } 387 if (check_key_not_revoked(hostkeys, k) != 0) { 388 end_return = HOST_REVOKED; 389 if (found != NULL) 390 *found = NULL; 391 } 392 return end_return; 393 } 394 395 HostStatus 396 check_key_in_hostkeys(struct hostkeys *hostkeys, struct sshkey *key, 397 const struct hostkey_entry **found) 398 { 399 if (key == NULL) 400 fatal("no key to look up"); 401 return check_hostkeys_by_key_or_type(hostkeys, key, 0, found); 402 } 403 404 int 405 lookup_key_in_hostkeys_by_type(struct hostkeys *hostkeys, int keytype, 406 const struct hostkey_entry **found) 407 { 408 return (check_hostkeys_by_key_or_type(hostkeys, NULL, keytype, 409 found) == HOST_FOUND); 410 } 411 412 static int 413 write_host_entry(FILE *f, const char *host, const char *ip, 414 const struct sshkey *key, int store_hash) 415 { 416 int r, success = 0; 417 char *hashed_host = NULL, *lhost; 418 419 lhost = xstrdup(host); 420 lowercase(lhost); 421 422 if (store_hash) { 423 if ((hashed_host = host_hash(lhost, NULL, 0)) == NULL) { 424 error("%s: host_hash failed", __func__); 425 free(lhost); 426 return 0; 427 } 428 fprintf(f, "%s ", hashed_host); 429 } else if (ip != NULL) 430 fprintf(f, "%s,%s ", lhost, ip); 431 else { 432 fprintf(f, "%s ", lhost); 433 } 434 free(lhost); 435 if ((r = sshkey_write(key, f)) == 0) 436 success = 1; 437 else 438 error("%s: sshkey_write failed: %s", __func__, ssh_err(r)); 439 fputc('\n', f); 440 return success; 441 } 442 443 /* 444 * Appends an entry to the host file. Returns false if the entry could not 445 * be appended. 446 */ 447 int 448 add_host_to_hostfile(const char *filename, const char *host, 449 const struct sshkey *key, int store_hash) 450 { 451 FILE *f; 452 int success; 453 454 if (key == NULL) 455 return 1; /* XXX ? */ 456 f = fopen(filename, "a"); 457 if (!f) 458 return 0; 459 success = write_host_entry(f, host, NULL, key, store_hash); 460 fclose(f); 461 return success; 462 } 463 464 struct host_delete_ctx { 465 FILE *out; 466 int quiet; 467 const char *host; 468 int *skip_keys; /* XXX split for host/ip? might want to ensure both */ 469 struct sshkey * const *keys; 470 size_t nkeys; 471 int modified; 472 }; 473 474 static int 475 host_delete(struct hostkey_foreach_line *l, void *_ctx) 476 { 477 struct host_delete_ctx *ctx = (struct host_delete_ctx *)_ctx; 478 int loglevel = ctx->quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE; 479 size_t i; 480 481 if (l->status == HKF_STATUS_MATCHED) { 482 if (l->marker != MRK_NONE) { 483 /* Don't remove CA and revocation lines */ 484 fprintf(ctx->out, "%s\n", l->line); 485 return 0; 486 } 487 488 /* 489 * If this line contains one of the keys that we will be 490 * adding later, then don't change it and mark the key for 491 * skipping. 492 */ 493 for (i = 0; i < ctx->nkeys; i++) { 494 if (sshkey_equal(ctx->keys[i], l->key)) { 495 ctx->skip_keys[i] = 1; 496 fprintf(ctx->out, "%s\n", l->line); 497 debug3("%s: %s key already at %s:%ld", __func__, 498 sshkey_type(l->key), l->path, l->linenum); 499 return 0; 500 } 501 } 502 503 /* 504 * Hostname matches and has no CA/revoke marker, delete it 505 * by *not* writing the line to ctx->out. 506 */ 507 do_log2(loglevel, "%s%s%s:%ld: Removed %s key for host %s", 508 ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "", 509 l->path, l->linenum, sshkey_type(l->key), ctx->host); 510 ctx->modified = 1; 511 return 0; 512 } 513 /* Retain non-matching hosts and invalid lines when deleting */ 514 if (l->status == HKF_STATUS_INVALID) { 515 do_log2(loglevel, "%s%s%s:%ld: invalid known_hosts entry", 516 ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "", 517 l->path, l->linenum); 518 } 519 fprintf(ctx->out, "%s\n", l->line); 520 return 0; 521 } 522 523 int 524 hostfile_replace_entries(const char *filename, const char *host, const char *ip, 525 struct sshkey **keys, size_t nkeys, int store_hash, int quiet, int hash_alg) 526 { 527 int r, fd, oerrno = 0; 528 int loglevel = quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE; 529 struct host_delete_ctx ctx; 530 char *fp, *temp = NULL, *back = NULL; 531 mode_t omask; 532 size_t i; 533 534 omask = umask(077); 535 536 memset(&ctx, 0, sizeof(ctx)); 537 ctx.host = host; 538 ctx.quiet = quiet; 539 if ((ctx.skip_keys = calloc(nkeys, sizeof(*ctx.skip_keys))) == NULL) 540 return SSH_ERR_ALLOC_FAIL; 541 ctx.keys = keys; 542 ctx.nkeys = nkeys; 543 ctx.modified = 0; 544 545 /* 546 * Prepare temporary file for in-place deletion. 547 */ 548 if ((r = asprintf(&temp, "%s.XXXXXXXXXXX", filename)) < 0 || 549 (r = asprintf(&back, "%s.old", filename)) < 0) { 550 r = SSH_ERR_ALLOC_FAIL; 551 goto fail; 552 } 553 554 if ((fd = mkstemp(temp)) == -1) { 555 oerrno = errno; 556 error("%s: mkstemp: %s", __func__, strerror(oerrno)); 557 r = SSH_ERR_SYSTEM_ERROR; 558 goto fail; 559 } 560 if ((ctx.out = fdopen(fd, "w")) == NULL) { 561 oerrno = errno; 562 close(fd); 563 error("%s: fdopen: %s", __func__, strerror(oerrno)); 564 r = SSH_ERR_SYSTEM_ERROR; 565 goto fail; 566 } 567 568 /* Remove all entries for the specified host from the file */ 569 if ((r = hostkeys_foreach(filename, host_delete, &ctx, host, ip, 570 HKF_WANT_PARSE_KEY)) != 0) { 571 error("%s: hostkeys_foreach failed: %s", __func__, ssh_err(r)); 572 goto fail; 573 } 574 575 /* Add the requested keys */ 576 for (i = 0; i < nkeys; i++) { 577 if (ctx.skip_keys[i]) 578 continue; 579 if ((fp = sshkey_fingerprint(keys[i], hash_alg, 580 SSH_FP_DEFAULT)) == NULL) { 581 r = SSH_ERR_ALLOC_FAIL; 582 goto fail; 583 } 584 do_log2(loglevel, "%s%sAdding new key for %s to %s: %s %s", 585 quiet ? __func__ : "", quiet ? ": " : "", host, filename, 586 sshkey_ssh_name(keys[i]), fp); 587 free(fp); 588 if (!write_host_entry(ctx.out, host, ip, keys[i], store_hash)) { 589 r = SSH_ERR_INTERNAL_ERROR; 590 goto fail; 591 } 592 ctx.modified = 1; 593 } 594 fclose(ctx.out); 595 ctx.out = NULL; 596 597 if (ctx.modified) { 598 /* Backup the original file and replace it with the temporary */ 599 if (unlink(back) == -1 && errno != ENOENT) { 600 oerrno = errno; 601 error("%s: unlink %.100s: %s", __func__, 602 back, strerror(errno)); 603 r = SSH_ERR_SYSTEM_ERROR; 604 goto fail; 605 } 606 if (link(filename, back) == -1) { 607 oerrno = errno; 608 error("%s: link %.100s to %.100s: %s", __func__, 609 filename, back, strerror(errno)); 610 r = SSH_ERR_SYSTEM_ERROR; 611 goto fail; 612 } 613 if (rename(temp, filename) == -1) { 614 oerrno = errno; 615 error("%s: rename \"%s\" to \"%s\": %s", __func__, 616 temp, filename, strerror(errno)); 617 r = SSH_ERR_SYSTEM_ERROR; 618 goto fail; 619 } 620 } else { 621 /* No changes made; just delete the temporary file */ 622 if (unlink(temp) != 0) 623 error("%s: unlink \"%s\": %s", __func__, 624 temp, strerror(errno)); 625 } 626 627 /* success */ 628 r = 0; 629 fail: 630 if (temp != NULL && r != 0) 631 unlink(temp); 632 free(temp); 633 free(back); 634 if (ctx.out != NULL) 635 fclose(ctx.out); 636 free(ctx.skip_keys); 637 umask(omask); 638 if (r == SSH_ERR_SYSTEM_ERROR) 639 errno = oerrno; 640 return r; 641 } 642 643 static int 644 match_maybe_hashed(const char *host, const char *names, int *was_hashed) 645 { 646 int hashed = *names == HASH_DELIM; 647 const char *hashed_host; 648 size_t nlen = strlen(names); 649 650 if (was_hashed != NULL) 651 *was_hashed = hashed; 652 if (hashed) { 653 if ((hashed_host = host_hash(host, names, nlen)) == NULL) 654 return -1; 655 return nlen == strlen(hashed_host) && 656 strncmp(hashed_host, names, nlen) == 0; 657 } 658 return match_hostname(host, names) == 1; 659 } 660 661 int 662 hostkeys_foreach(const char *path, hostkeys_foreach_fn *callback, void *ctx, 663 const char *host, const char *ip, u_int options) 664 { 665 FILE *f; 666 char line[8192], oline[8192], ktype[128]; 667 u_long linenum = 0; 668 char *cp, *cp2; 669 u_int kbits; 670 int hashed; 671 int s, r = 0; 672 struct hostkey_foreach_line lineinfo; 673 size_t l; 674 675 memset(&lineinfo, 0, sizeof(lineinfo)); 676 if (host == NULL && (options & HKF_WANT_MATCH) != 0) 677 return SSH_ERR_INVALID_ARGUMENT; 678 if ((f = fopen(path, "r")) == NULL) 679 return SSH_ERR_SYSTEM_ERROR; 680 681 debug3("%s: reading file \"%s\"", __func__, path); 682 while (read_keyfile_line(f, path, line, sizeof(line), &linenum) == 0) { 683 line[strcspn(line, "\n")] = '\0'; 684 strlcpy(oline, line, sizeof(oline)); 685 686 sshkey_free(lineinfo.key); 687 memset(&lineinfo, 0, sizeof(lineinfo)); 688 lineinfo.path = path; 689 lineinfo.linenum = linenum; 690 lineinfo.line = oline; 691 lineinfo.marker = MRK_NONE; 692 lineinfo.status = HKF_STATUS_OK; 693 lineinfo.keytype = KEY_UNSPEC; 694 695 /* Skip any leading whitespace, comments and empty lines. */ 696 for (cp = line; *cp == ' ' || *cp == '\t'; cp++) 697 ; 698 if (!*cp || *cp == '#' || *cp == '\n') { 699 if ((options & HKF_WANT_MATCH) == 0) { 700 lineinfo.status = HKF_STATUS_COMMENT; 701 if ((r = callback(&lineinfo, ctx)) != 0) 702 break; 703 } 704 continue; 705 } 706 707 if ((lineinfo.marker = check_markers(&cp)) == MRK_ERROR) { 708 verbose("%s: invalid marker at %s:%lu", 709 __func__, path, linenum); 710 if ((options & HKF_WANT_MATCH) == 0) 711 goto bad; 712 continue; 713 } 714 715 /* Find the end of the host name portion. */ 716 for (cp2 = cp; *cp2 && *cp2 != ' ' && *cp2 != '\t'; cp2++) 717 ; 718 lineinfo.hosts = cp; 719 *cp2++ = '\0'; 720 721 /* Check if the host name matches. */ 722 if (host != NULL) { 723 if ((s = match_maybe_hashed(host, lineinfo.hosts, 724 &hashed)) == -1) { 725 debug2("%s: %s:%ld: bad host hash \"%.32s\"", 726 __func__, path, linenum, lineinfo.hosts); 727 goto bad; 728 } 729 if (s == 1) { 730 lineinfo.status = HKF_STATUS_MATCHED; 731 lineinfo.match |= HKF_MATCH_HOST | 732 (hashed ? HKF_MATCH_HOST_HASHED : 0); 733 } 734 /* Try matching IP address if supplied */ 735 if (ip != NULL) { 736 if ((s = match_maybe_hashed(ip, lineinfo.hosts, 737 &hashed)) == -1) { 738 debug2("%s: %s:%ld: bad ip hash " 739 "\"%.32s\"", __func__, path, 740 linenum, lineinfo.hosts); 741 goto bad; 742 } 743 if (s == 1) { 744 lineinfo.status = HKF_STATUS_MATCHED; 745 lineinfo.match |= HKF_MATCH_IP | 746 (hashed ? HKF_MATCH_IP_HASHED : 0); 747 } 748 } 749 /* 750 * Skip this line if host matching requested and 751 * neither host nor address matched. 752 */ 753 if ((options & HKF_WANT_MATCH) != 0 && 754 lineinfo.status != HKF_STATUS_MATCHED) 755 continue; 756 } 757 758 /* Got a match. Skip host name and any following whitespace */ 759 for (; *cp2 == ' ' || *cp2 == '\t'; cp2++) 760 ; 761 if (*cp2 == '\0' || *cp2 == '#') { 762 debug2("%s:%ld: truncated before key type", 763 path, linenum); 764 goto bad; 765 } 766 lineinfo.rawkey = cp = cp2; 767 768 if ((options & HKF_WANT_PARSE_KEY) != 0) { 769 /* 770 * Extract the key from the line. This will skip 771 * any leading whitespace. Ignore badly formatted 772 * lines. 773 */ 774 if ((lineinfo.key = sshkey_new(KEY_UNSPEC)) == NULL) { 775 error("%s: sshkey_new failed", __func__); 776 r = SSH_ERR_ALLOC_FAIL; 777 break; 778 } 779 if (!hostfile_read_key(&cp, &kbits, lineinfo.key)) { 780 goto bad; 781 } 782 lineinfo.keytype = lineinfo.key->type; 783 lineinfo.comment = cp; 784 } else { 785 /* Extract and parse key type */ 786 l = strcspn(lineinfo.rawkey, " \t"); 787 if (l <= 1 || l >= sizeof(ktype) || 788 lineinfo.rawkey[l] == '\0') 789 goto bad; 790 memcpy(ktype, lineinfo.rawkey, l); 791 ktype[l] = '\0'; 792 lineinfo.keytype = sshkey_type_from_name(ktype); 793 794 /* 795 * Assume legacy RSA1 if the first component is a short 796 * decimal number. 797 */ 798 if (lineinfo.keytype == KEY_UNSPEC && l < 8 && 799 strspn(ktype, "0123456789") == l) 800 goto bad; 801 802 /* 803 * Check that something other than whitespace follows 804 * the key type. This won't catch all corruption, but 805 * it does catch trivial truncation. 806 */ 807 cp2 += l; /* Skip past key type */ 808 for (; *cp2 == ' ' || *cp2 == '\t'; cp2++) 809 ; 810 if (*cp2 == '\0' || *cp2 == '#') { 811 debug2("%s:%ld: truncated after key type", 812 path, linenum); 813 lineinfo.keytype = KEY_UNSPEC; 814 } 815 if (lineinfo.keytype == KEY_UNSPEC) { 816 bad: 817 sshkey_free(lineinfo.key); 818 lineinfo.key = NULL; 819 lineinfo.status = HKF_STATUS_INVALID; 820 if ((r = callback(&lineinfo, ctx)) != 0) 821 break; 822 continue; 823 } 824 } 825 if ((r = callback(&lineinfo, ctx)) != 0) 826 break; 827 } 828 sshkey_free(lineinfo.key); 829 fclose(f); 830 return r; 831 } 832