1 /* $OpenBSD: hostfile.c,v 1.67 2016/09/17 18:00:27 tedu 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 = reallocarray(hostkeys->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 int proto = (k ? k->type : keytype) == KEY_RSA1 ? 1 : 2; 350 351 if (found != NULL) 352 *found = NULL; 353 354 for (i = 0; i < hostkeys->num_entries; i++) { 355 if (proto == 1 && hostkeys->entries[i].key->type != KEY_RSA1) 356 continue; 357 if (proto == 2 && hostkeys->entries[i].key->type == KEY_RSA1) 358 continue; 359 if (hostkeys->entries[i].marker != want_marker) 360 continue; 361 if (k == NULL) { 362 if (hostkeys->entries[i].key->type != keytype) 363 continue; 364 end_return = HOST_FOUND; 365 if (found != NULL) 366 *found = hostkeys->entries + i; 367 k = hostkeys->entries[i].key; 368 break; 369 } 370 if (want_cert) { 371 if (sshkey_equal_public(k->cert->signature_key, 372 hostkeys->entries[i].key)) { 373 /* A matching CA exists */ 374 end_return = HOST_OK; 375 if (found != NULL) 376 *found = hostkeys->entries + i; 377 break; 378 } 379 } else { 380 if (sshkey_equal(k, hostkeys->entries[i].key)) { 381 end_return = HOST_OK; 382 if (found != NULL) 383 *found = hostkeys->entries + i; 384 break; 385 } 386 /* A non-maching key exists */ 387 end_return = HOST_CHANGED; 388 if (found != NULL) 389 *found = hostkeys->entries + i; 390 } 391 } 392 if (check_key_not_revoked(hostkeys, k) != 0) { 393 end_return = HOST_REVOKED; 394 if (found != NULL) 395 *found = NULL; 396 } 397 return end_return; 398 } 399 400 HostStatus 401 check_key_in_hostkeys(struct hostkeys *hostkeys, struct sshkey *key, 402 const struct hostkey_entry **found) 403 { 404 if (key == NULL) 405 fatal("no key to look up"); 406 return check_hostkeys_by_key_or_type(hostkeys, key, 0, found); 407 } 408 409 int 410 lookup_key_in_hostkeys_by_type(struct hostkeys *hostkeys, int keytype, 411 const struct hostkey_entry **found) 412 { 413 return (check_hostkeys_by_key_or_type(hostkeys, NULL, keytype, 414 found) == HOST_FOUND); 415 } 416 417 static int 418 write_host_entry(FILE *f, const char *host, const char *ip, 419 const struct sshkey *key, int store_hash) 420 { 421 int r, success = 0; 422 char *hashed_host = NULL; 423 424 if (store_hash) { 425 if ((hashed_host = host_hash(host, NULL, 0)) == NULL) { 426 error("%s: host_hash failed", __func__); 427 return 0; 428 } 429 fprintf(f, "%s ", hashed_host); 430 } else if (ip != NULL) 431 fprintf(f, "%s,%s ", host, ip); 432 else 433 fprintf(f, "%s ", host); 434 435 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 /* XXX might need a knob for this later */ 489 /* Don't remove RSA1 keys */ 490 if (l->key->type == KEY_RSA1) { 491 fprintf(ctx->out, "%s\n", l->line); 492 return 0; 493 } 494 495 /* 496 * If this line contains one of the keys that we will be 497 * adding later, then don't change it and mark the key for 498 * skipping. 499 */ 500 for (i = 0; i < ctx->nkeys; i++) { 501 if (sshkey_equal(ctx->keys[i], l->key)) { 502 ctx->skip_keys[i] = 1; 503 fprintf(ctx->out, "%s\n", l->line); 504 debug3("%s: %s key already at %s:%ld", __func__, 505 sshkey_type(l->key), l->path, l->linenum); 506 return 0; 507 } 508 } 509 510 /* 511 * Hostname matches and has no CA/revoke marker, delete it 512 * by *not* writing the line to ctx->out. 513 */ 514 do_log2(loglevel, "%s%s%s:%ld: Removed %s key for host %s", 515 ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "", 516 l->path, l->linenum, sshkey_type(l->key), ctx->host); 517 ctx->modified = 1; 518 return 0; 519 } 520 /* Retain non-matching hosts and invalid lines when deleting */ 521 if (l->status == HKF_STATUS_INVALID) { 522 do_log2(loglevel, "%s%s%s:%ld: invalid known_hosts entry", 523 ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "", 524 l->path, l->linenum); 525 } 526 fprintf(ctx->out, "%s\n", l->line); 527 return 0; 528 } 529 530 int 531 hostfile_replace_entries(const char *filename, const char *host, const char *ip, 532 struct sshkey **keys, size_t nkeys, int store_hash, int quiet, int hash_alg) 533 { 534 int r, fd, oerrno = 0; 535 int loglevel = quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE; 536 struct host_delete_ctx ctx; 537 char *fp, *temp = NULL, *back = NULL; 538 mode_t omask; 539 size_t i; 540 541 omask = umask(077); 542 543 memset(&ctx, 0, sizeof(ctx)); 544 ctx.host = host; 545 ctx.quiet = quiet; 546 if ((ctx.skip_keys = calloc(nkeys, sizeof(*ctx.skip_keys))) == NULL) 547 return SSH_ERR_ALLOC_FAIL; 548 ctx.keys = keys; 549 ctx.nkeys = nkeys; 550 ctx.modified = 0; 551 552 /* 553 * Prepare temporary file for in-place deletion. 554 */ 555 if ((r = asprintf(&temp, "%s.XXXXXXXXXXX", filename)) < 0 || 556 (r = asprintf(&back, "%s.old", filename)) < 0) { 557 r = SSH_ERR_ALLOC_FAIL; 558 goto fail; 559 } 560 561 if ((fd = mkstemp(temp)) == -1) { 562 oerrno = errno; 563 error("%s: mkstemp: %s", __func__, strerror(oerrno)); 564 r = SSH_ERR_SYSTEM_ERROR; 565 goto fail; 566 } 567 if ((ctx.out = fdopen(fd, "w")) == NULL) { 568 oerrno = errno; 569 close(fd); 570 error("%s: fdopen: %s", __func__, strerror(oerrno)); 571 r = SSH_ERR_SYSTEM_ERROR; 572 goto fail; 573 } 574 575 /* Remove all entries for the specified host from the file */ 576 if ((r = hostkeys_foreach(filename, host_delete, &ctx, host, ip, 577 HKF_WANT_PARSE_KEY)) != 0) { 578 error("%s: hostkeys_foreach failed: %s", __func__, ssh_err(r)); 579 goto fail; 580 } 581 582 /* Add the requested keys */ 583 for (i = 0; i < nkeys; i++) { 584 if (ctx.skip_keys[i]) 585 continue; 586 if ((fp = sshkey_fingerprint(keys[i], hash_alg, 587 SSH_FP_DEFAULT)) == NULL) { 588 r = SSH_ERR_ALLOC_FAIL; 589 goto fail; 590 } 591 do_log2(loglevel, "%s%sAdding new key for %s to %s: %s %s", 592 quiet ? __func__ : "", quiet ? ": " : "", host, filename, 593 sshkey_ssh_name(keys[i]), fp); 594 free(fp); 595 if (!write_host_entry(ctx.out, host, ip, keys[i], store_hash)) { 596 r = SSH_ERR_INTERNAL_ERROR; 597 goto fail; 598 } 599 ctx.modified = 1; 600 } 601 fclose(ctx.out); 602 ctx.out = NULL; 603 604 if (ctx.modified) { 605 /* Backup the original file and replace it with the temporary */ 606 if (unlink(back) == -1 && errno != ENOENT) { 607 oerrno = errno; 608 error("%s: unlink %.100s: %s", __func__, 609 back, strerror(errno)); 610 r = SSH_ERR_SYSTEM_ERROR; 611 goto fail; 612 } 613 if (link(filename, back) == -1) { 614 oerrno = errno; 615 error("%s: link %.100s to %.100s: %s", __func__, 616 filename, back, strerror(errno)); 617 r = SSH_ERR_SYSTEM_ERROR; 618 goto fail; 619 } 620 if (rename(temp, filename) == -1) { 621 oerrno = errno; 622 error("%s: rename \"%s\" to \"%s\": %s", __func__, 623 temp, filename, strerror(errno)); 624 r = SSH_ERR_SYSTEM_ERROR; 625 goto fail; 626 } 627 } else { 628 /* No changes made; just delete the temporary file */ 629 if (unlink(temp) != 0) 630 error("%s: unlink \"%s\": %s", __func__, 631 temp, strerror(errno)); 632 } 633 634 /* success */ 635 r = 0; 636 fail: 637 if (temp != NULL && r != 0) 638 unlink(temp); 639 free(temp); 640 free(back); 641 if (ctx.out != NULL) 642 fclose(ctx.out); 643 free(ctx.skip_keys); 644 umask(omask); 645 if (r == SSH_ERR_SYSTEM_ERROR) 646 errno = oerrno; 647 return r; 648 } 649 650 static int 651 match_maybe_hashed(const char *host, const char *names, int *was_hashed) 652 { 653 int hashed = *names == HASH_DELIM; 654 const char *hashed_host; 655 size_t nlen = strlen(names); 656 657 if (was_hashed != NULL) 658 *was_hashed = hashed; 659 if (hashed) { 660 if ((hashed_host = host_hash(host, names, nlen)) == NULL) 661 return -1; 662 return nlen == strlen(hashed_host) && 663 strncmp(hashed_host, names, nlen) == 0; 664 } 665 return match_hostname(host, names) == 1; 666 } 667 668 int 669 hostkeys_foreach(const char *path, hostkeys_foreach_fn *callback, void *ctx, 670 const char *host, const char *ip, u_int options) 671 { 672 FILE *f; 673 char line[8192], oline[8192], ktype[128]; 674 u_long linenum = 0; 675 char *cp, *cp2; 676 u_int kbits; 677 int hashed; 678 int s, r = 0; 679 struct hostkey_foreach_line lineinfo; 680 size_t l; 681 682 memset(&lineinfo, 0, sizeof(lineinfo)); 683 if (host == NULL && (options & HKF_WANT_MATCH) != 0) 684 return SSH_ERR_INVALID_ARGUMENT; 685 if ((f = fopen(path, "r")) == NULL) 686 return SSH_ERR_SYSTEM_ERROR; 687 688 debug3("%s: reading file \"%s\"", __func__, path); 689 while (read_keyfile_line(f, path, line, sizeof(line), &linenum) == 0) { 690 line[strcspn(line, "\n")] = '\0'; 691 strlcpy(oline, line, sizeof(oline)); 692 693 sshkey_free(lineinfo.key); 694 memset(&lineinfo, 0, sizeof(lineinfo)); 695 lineinfo.path = path; 696 lineinfo.linenum = linenum; 697 lineinfo.line = oline; 698 lineinfo.marker = MRK_NONE; 699 lineinfo.status = HKF_STATUS_OK; 700 lineinfo.keytype = KEY_UNSPEC; 701 702 /* Skip any leading whitespace, comments and empty lines. */ 703 for (cp = line; *cp == ' ' || *cp == '\t'; cp++) 704 ; 705 if (!*cp || *cp == '#' || *cp == '\n') { 706 if ((options & HKF_WANT_MATCH) == 0) { 707 lineinfo.status = HKF_STATUS_COMMENT; 708 if ((r = callback(&lineinfo, ctx)) != 0) 709 break; 710 } 711 continue; 712 } 713 714 if ((lineinfo.marker = check_markers(&cp)) == MRK_ERROR) { 715 verbose("%s: invalid marker at %s:%lu", 716 __func__, path, linenum); 717 if ((options & HKF_WANT_MATCH) == 0) 718 goto bad; 719 continue; 720 } 721 722 /* Find the end of the host name portion. */ 723 for (cp2 = cp; *cp2 && *cp2 != ' ' && *cp2 != '\t'; cp2++) 724 ; 725 lineinfo.hosts = cp; 726 *cp2++ = '\0'; 727 728 /* Check if the host name matches. */ 729 if (host != NULL) { 730 if ((s = match_maybe_hashed(host, lineinfo.hosts, 731 &hashed)) == -1) { 732 debug2("%s: %s:%ld: bad host hash \"%.32s\"", 733 __func__, path, linenum, lineinfo.hosts); 734 goto bad; 735 } 736 if (s == 1) { 737 lineinfo.status = HKF_STATUS_MATCHED; 738 lineinfo.match |= HKF_MATCH_HOST | 739 (hashed ? HKF_MATCH_HOST_HASHED : 0); 740 } 741 /* Try matching IP address if supplied */ 742 if (ip != NULL) { 743 if ((s = match_maybe_hashed(ip, lineinfo.hosts, 744 &hashed)) == -1) { 745 debug2("%s: %s:%ld: bad ip hash " 746 "\"%.32s\"", __func__, path, 747 linenum, lineinfo.hosts); 748 goto bad; 749 } 750 if (s == 1) { 751 lineinfo.status = HKF_STATUS_MATCHED; 752 lineinfo.match |= HKF_MATCH_IP | 753 (hashed ? HKF_MATCH_IP_HASHED : 0); 754 } 755 } 756 /* 757 * Skip this line if host matching requested and 758 * neither host nor address matched. 759 */ 760 if ((options & HKF_WANT_MATCH) != 0 && 761 lineinfo.status != HKF_STATUS_MATCHED) 762 continue; 763 } 764 765 /* Got a match. Skip host name and any following whitespace */ 766 for (; *cp2 == ' ' || *cp2 == '\t'; cp2++) 767 ; 768 if (*cp2 == '\0' || *cp2 == '#') { 769 debug2("%s:%ld: truncated before key type", 770 path, linenum); 771 goto bad; 772 } 773 lineinfo.rawkey = cp = cp2; 774 775 if ((options & HKF_WANT_PARSE_KEY) != 0) { 776 /* 777 * Extract the key from the line. This will skip 778 * any leading whitespace. Ignore badly formatted 779 * lines. 780 */ 781 if ((lineinfo.key = sshkey_new(KEY_UNSPEC)) == NULL) { 782 error("%s: sshkey_new failed", __func__); 783 r = SSH_ERR_ALLOC_FAIL; 784 break; 785 } 786 if (!hostfile_read_key(&cp, &kbits, lineinfo.key)) { 787 #ifdef WITH_SSH1 788 sshkey_free(lineinfo.key); 789 lineinfo.key = sshkey_new(KEY_RSA1); 790 if (lineinfo.key == NULL) { 791 error("%s: sshkey_new fail", __func__); 792 r = SSH_ERR_ALLOC_FAIL; 793 break; 794 } 795 if (!hostfile_read_key(&cp, &kbits, 796 lineinfo.key)) 797 goto bad; 798 #else 799 goto bad; 800 #endif 801 } 802 lineinfo.keytype = lineinfo.key->type; 803 lineinfo.comment = cp; 804 } else { 805 /* Extract and parse key type */ 806 l = strcspn(lineinfo.rawkey, " \t"); 807 if (l <= 1 || l >= sizeof(ktype) || 808 lineinfo.rawkey[l] == '\0') 809 goto bad; 810 memcpy(ktype, lineinfo.rawkey, l); 811 ktype[l] = '\0'; 812 lineinfo.keytype = sshkey_type_from_name(ktype); 813 814 /* 815 * Assume RSA1 if the first component is a short 816 * decimal number. 817 */ 818 if (lineinfo.keytype == KEY_UNSPEC && l < 8 && 819 strspn(ktype, "0123456789") == l) 820 lineinfo.keytype = KEY_RSA1; 821 822 /* 823 * Check that something other than whitespace follows 824 * the key type. This won't catch all corruption, but 825 * it does catch trivial truncation. 826 */ 827 cp2 += l; /* Skip past key type */ 828 for (; *cp2 == ' ' || *cp2 == '\t'; cp2++) 829 ; 830 if (*cp2 == '\0' || *cp2 == '#') { 831 debug2("%s:%ld: truncated after key type", 832 path, linenum); 833 lineinfo.keytype = KEY_UNSPEC; 834 } 835 if (lineinfo.keytype == KEY_UNSPEC) { 836 bad: 837 sshkey_free(lineinfo.key); 838 lineinfo.key = NULL; 839 lineinfo.status = HKF_STATUS_INVALID; 840 if ((r = callback(&lineinfo, ctx)) != 0) 841 break; 842 continue; 843 } 844 } 845 if ((r = callback(&lineinfo, ctx)) != 0) 846 break; 847 } 848 sshkey_free(lineinfo.key); 849 fclose(f); 850 return r; 851 } 852