hostfile.c revision 1.10
1/* $NetBSD: hostfile.c,v 1.10 2017/04/18 18:41:46 christos Exp $ */ 2/* $OpenBSD: hostfile.c,v 1.68 2017/03/10 04:26:06 djm Exp $ */ 3/* 4 * Author: Tatu Ylonen <ylo@cs.hut.fi> 5 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 6 * All rights reserved 7 * Functions for manipulating the known hosts files. 8 * 9 * As far as I am concerned, the code I have written for this software 10 * can be used freely for any purpose. Any derived versions of this 11 * software must be clearly marked as such, and if the derived work is 12 * incompatible with the protocol description in the RFC file, it must be 13 * called by a name other than "ssh" or "Secure Shell". 14 * 15 * 16 * Copyright (c) 1999, 2000 Markus Friedl. All rights reserved. 17 * Copyright (c) 1999 Niels Provos. All rights reserved. 18 * 19 * Redistribution and use in source and binary forms, with or without 20 * modification, are permitted provided that the following conditions 21 * are met: 22 * 1. Redistributions of source code must retain the above copyright 23 * notice, this list of conditions and the following disclaimer. 24 * 2. Redistributions in binary form must reproduce the above copyright 25 * notice, this list of conditions and the following disclaimer in the 26 * documentation and/or other materials provided with the distribution. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 29 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 30 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 31 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 32 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 33 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 34 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 35 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 36 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 37 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 38 */ 39 40#include "includes.h" 41__RCSID("$NetBSD: hostfile.c,v 1.10 2017/04/18 18:41:46 christos Exp $"); 42#include <sys/types.h> 43#include <sys/stat.h> 44 45#include <netinet/in.h> 46 47#include <errno.h> 48#include <resolv.h> 49#include <stdio.h> 50#include <stdlib.h> 51#include <string.h> 52#include <stdarg.h> 53#include <time.h> 54#include <unistd.h> 55 56#include "xmalloc.h" 57#include "match.h" 58#include "sshkey.h" 59#include "hostfile.h" 60#include "log.h" 61#include "misc.h" 62#include "ssherr.h" 63#include "digest.h" 64#include "hmac.h" 65 66struct hostkeys { 67 struct hostkey_entry *entries; 68 u_int num_entries; 69}; 70 71/* XXX hmac is too easy to dictionary attack; use bcrypt? */ 72 73static int 74extract_salt(const char *s, u_int l, u_char *salt, size_t salt_len) 75{ 76 char *p, *b64salt; 77 u_int b64len; 78 int ret; 79 80 if (l < sizeof(HASH_MAGIC) - 1) { 81 debug2("extract_salt: string too short"); 82 return (-1); 83 } 84 if (strncmp(s, HASH_MAGIC, sizeof(HASH_MAGIC) - 1) != 0) { 85 debug2("extract_salt: invalid magic identifier"); 86 return (-1); 87 } 88 s += sizeof(HASH_MAGIC) - 1; 89 l -= sizeof(HASH_MAGIC) - 1; 90 if ((p = memchr(s, HASH_DELIM, l)) == NULL) { 91 debug2("extract_salt: missing salt termination character"); 92 return (-1); 93 } 94 95 b64len = p - s; 96 /* Sanity check */ 97 if (b64len == 0 || b64len > 1024) { 98 debug2("extract_salt: bad encoded salt length %u", b64len); 99 return (-1); 100 } 101 b64salt = xmalloc(1 + b64len); 102 memcpy(b64salt, s, b64len); 103 b64salt[b64len] = '\0'; 104 105 ret = __b64_pton(b64salt, salt, salt_len); 106 free(b64salt); 107 if (ret == -1) { 108 debug2("extract_salt: salt decode error"); 109 return (-1); 110 } 111 if (ret != (int)ssh_hmac_bytes(SSH_DIGEST_SHA1)) { 112 debug2("extract_salt: expected salt len %zd, got %d", 113 ssh_hmac_bytes(SSH_DIGEST_SHA1), ret); 114 return (-1); 115 } 116 117 return (0); 118} 119 120char * 121host_hash(const char *host, const char *name_from_hostfile, u_int src_len) 122{ 123 struct ssh_hmac_ctx *ctx; 124 u_char salt[256], result[256]; 125 char uu_salt[512], uu_result[512]; 126 static char encoded[1024]; 127 u_int len; 128 129 len = ssh_digest_bytes(SSH_DIGEST_SHA1); 130 131 if (name_from_hostfile == NULL) { 132 /* Create new salt */ 133 arc4random_buf(salt, len); 134 } else { 135 /* Extract salt from known host entry */ 136 if (extract_salt(name_from_hostfile, src_len, salt, 137 sizeof(salt)) == -1) 138 return (NULL); 139 } 140 141 if ((ctx = ssh_hmac_start(SSH_DIGEST_SHA1)) == NULL || 142 ssh_hmac_init(ctx, salt, len) < 0 || 143 ssh_hmac_update(ctx, host, strlen(host)) < 0 || 144 ssh_hmac_final(ctx, result, sizeof(result))) 145 fatal("%s: ssh_hmac failed", __func__); 146 ssh_hmac_free(ctx); 147 148 if (__b64_ntop(salt, len, uu_salt, sizeof(uu_salt)) == -1 || 149 __b64_ntop(result, len, uu_result, sizeof(uu_result)) == -1) 150 fatal("%s: __b64_ntop failed", __func__); 151 152 snprintf(encoded, sizeof(encoded), "%s%s%c%s", HASH_MAGIC, uu_salt, 153 HASH_DELIM, uu_result); 154 155 return (encoded); 156} 157 158/* 159 * Parses an RSA (number of bits, e, n) or DSA key from a string. Moves the 160 * pointer over the key. Skips any whitespace at the beginning and at end. 161 */ 162 163int 164hostfile_read_key(char **cpp, u_int *bitsp, struct sshkey *ret) 165{ 166 char *cp; 167 int r; 168 169 /* Skip leading whitespace. */ 170 for (cp = *cpp; *cp == ' ' || *cp == '\t'; cp++) 171 ; 172 173 if ((r = sshkey_read(ret, &cp)) != 0) 174 return 0; 175 176 /* Skip trailing whitespace. */ 177 for (; *cp == ' ' || *cp == '\t'; cp++) 178 ; 179 180 /* Return results. */ 181 *cpp = cp; 182 if (bitsp != NULL) 183 *bitsp = sshkey_size(ret); 184 return 1; 185} 186 187static HostkeyMarker 188check_markers(char **cpp) 189{ 190 char marker[32], *sp, *cp = *cpp; 191 int ret = MRK_NONE; 192 193 while (*cp == '@') { 194 /* Only one marker is allowed */ 195 if (ret != MRK_NONE) 196 return MRK_ERROR; 197 /* Markers are terminated by whitespace */ 198 if ((sp = strchr(cp, ' ')) == NULL && 199 (sp = strchr(cp, '\t')) == NULL) 200 return MRK_ERROR; 201 /* Extract marker for comparison */ 202 if (sp <= cp + 1 || sp >= cp + sizeof(marker)) 203 return MRK_ERROR; 204 memcpy(marker, cp, sp - cp); 205 marker[sp - cp] = '\0'; 206 if (strcmp(marker, CA_MARKER) == 0) 207 ret = MRK_CA; 208 else if (strcmp(marker, REVOKE_MARKER) == 0) 209 ret = MRK_REVOKE; 210 else 211 return MRK_ERROR; 212 213 /* Skip past marker and any whitespace that follows it */ 214 cp = sp; 215 for (; *cp == ' ' || *cp == '\t'; cp++) 216 ; 217 } 218 *cpp = cp; 219 return ret; 220} 221 222struct hostkeys * 223init_hostkeys(void) 224{ 225 struct hostkeys *ret = xcalloc(1, sizeof(*ret)); 226 227 ret->entries = NULL; 228 return ret; 229} 230 231struct load_callback_ctx { 232 const char *host; 233 u_long num_loaded; 234 struct hostkeys *hostkeys; 235}; 236 237static int 238record_hostkey(struct hostkey_foreach_line *l, void *_ctx) 239{ 240 struct load_callback_ctx *ctx = (struct load_callback_ctx *)_ctx; 241 struct hostkeys *hostkeys = ctx->hostkeys; 242 struct hostkey_entry *tmp; 243 244 if (l->status == HKF_STATUS_INVALID) { 245 /* XXX make this verbose() in the future */ 246 debug("%s:%ld: parse error in hostkeys file", 247 l->path, l->linenum); 248 return 0; 249 } 250 251 debug3("%s: found %skey type %s in file %s:%lu", __func__, 252 l->marker == MRK_NONE ? "" : 253 (l->marker == MRK_CA ? "ca " : "revoked "), 254 sshkey_type(l->key), l->path, l->linenum); 255 if ((tmp = reallocarray(hostkeys->entries, 256 hostkeys->num_entries + 1, sizeof(*hostkeys->entries))) == NULL) 257 return SSH_ERR_ALLOC_FAIL; 258 hostkeys->entries = tmp; 259 hostkeys->entries[hostkeys->num_entries].host = xstrdup(ctx->host); 260 hostkeys->entries[hostkeys->num_entries].file = xstrdup(l->path); 261 hostkeys->entries[hostkeys->num_entries].line = l->linenum; 262 hostkeys->entries[hostkeys->num_entries].key = l->key; 263 l->key = NULL; /* steal it */ 264 hostkeys->entries[hostkeys->num_entries].marker = l->marker; 265 hostkeys->num_entries++; 266 ctx->num_loaded++; 267 268 return 0; 269} 270 271void 272load_hostkeys(struct hostkeys *hostkeys, const char *host, const char *path) 273{ 274 int r; 275 struct load_callback_ctx ctx; 276 277 ctx.host = host; 278 ctx.num_loaded = 0; 279 ctx.hostkeys = hostkeys; 280 281 if ((r = hostkeys_foreach(path, record_hostkey, &ctx, host, NULL, 282 HKF_WANT_MATCH|HKF_WANT_PARSE_KEY)) != 0) { 283 if (r != SSH_ERR_SYSTEM_ERROR && errno != ENOENT) 284 debug("%s: hostkeys_foreach failed for %s: %s", 285 __func__, path, ssh_err(r)); 286 } 287 if (ctx.num_loaded != 0) 288 debug3("%s: loaded %lu keys from %s", __func__, 289 ctx.num_loaded, host); 290} 291 292void 293free_hostkeys(struct hostkeys *hostkeys) 294{ 295 u_int i; 296 297 for (i = 0; i < hostkeys->num_entries; i++) { 298 free(hostkeys->entries[i].host); 299 free(hostkeys->entries[i].file); 300 sshkey_free(hostkeys->entries[i].key); 301 explicit_bzero(hostkeys->entries + i, sizeof(*hostkeys->entries)); 302 } 303 free(hostkeys->entries); 304 explicit_bzero(hostkeys, sizeof(*hostkeys)); 305 free(hostkeys); 306} 307 308static int 309check_key_not_revoked(struct hostkeys *hostkeys, struct sshkey *k) 310{ 311 int is_cert = sshkey_is_cert(k); 312 u_int i; 313 314 for (i = 0; i < hostkeys->num_entries; i++) { 315 if (hostkeys->entries[i].marker != MRK_REVOKE) 316 continue; 317 if (sshkey_equal_public(k, hostkeys->entries[i].key)) 318 return -1; 319 if (is_cert && 320 sshkey_equal_public(k->cert->signature_key, 321 hostkeys->entries[i].key)) 322 return -1; 323 } 324 return 0; 325} 326 327/* 328 * Match keys against a specified key, or look one up by key type. 329 * 330 * If looking for a keytype (key == NULL) and one is found then return 331 * HOST_FOUND, otherwise HOST_NEW. 332 * 333 * If looking for a key (key != NULL): 334 * 1. If the key is a cert and a matching CA is found, return HOST_OK 335 * 2. If the key is not a cert and a matching key is found, return HOST_OK 336 * 3. If no key matches but a key with a different type is found, then 337 * return HOST_CHANGED 338 * 4. If no matching keys are found, then return HOST_NEW. 339 * 340 * Finally, check any found key is not revoked. 341 */ 342static HostStatus 343check_hostkeys_by_key_or_type(struct hostkeys *hostkeys, 344 struct sshkey *k, int keytype, const struct hostkey_entry **found) 345{ 346 u_int i; 347 HostStatus end_return = HOST_NEW; 348 int want_cert = sshkey_is_cert(k); 349 HostkeyMarker want_marker = want_cert ? MRK_CA : MRK_NONE; 350 int proto = (k ? k->type : keytype) == KEY_RSA1 ? 1 : 2; 351 352 if (found != NULL) 353 *found = NULL; 354 355 for (i = 0; i < hostkeys->num_entries; i++) { 356 if (proto == 1 && hostkeys->entries[i].key->type != KEY_RSA1) 357 continue; 358 if (proto == 2 && hostkeys->entries[i].key->type == KEY_RSA1) 359 continue; 360 if (hostkeys->entries[i].marker != want_marker) 361 continue; 362 if (k == NULL) { 363 if (hostkeys->entries[i].key->type != keytype) 364 continue; 365 end_return = HOST_FOUND; 366 if (found != NULL) 367 *found = hostkeys->entries + i; 368 k = hostkeys->entries[i].key; 369 break; 370 } 371 if (want_cert) { 372 if (sshkey_equal_public(k->cert->signature_key, 373 hostkeys->entries[i].key)) { 374 /* A matching CA exists */ 375 end_return = HOST_OK; 376 if (found != NULL) 377 *found = hostkeys->entries + i; 378 break; 379 } 380 } else { 381 if (sshkey_equal(k, hostkeys->entries[i].key)) { 382 end_return = HOST_OK; 383 if (found != NULL) 384 *found = hostkeys->entries + i; 385 break; 386 } 387 /* A non-maching key exists */ 388 end_return = HOST_CHANGED; 389 if (found != NULL) 390 *found = hostkeys->entries + i; 391 } 392 } 393 if (check_key_not_revoked(hostkeys, k) != 0) { 394 end_return = HOST_REVOKED; 395 if (found != NULL) 396 *found = NULL; 397 } 398 return end_return; 399} 400 401HostStatus 402check_key_in_hostkeys(struct hostkeys *hostkeys, struct sshkey *key, 403 const struct hostkey_entry **found) 404{ 405 if (key == NULL) 406 fatal("no key to look up"); 407 return check_hostkeys_by_key_or_type(hostkeys, key, 0, found); 408} 409 410int 411lookup_key_in_hostkeys_by_type(struct hostkeys *hostkeys, int keytype, 412 const struct hostkey_entry **found) 413{ 414 return (check_hostkeys_by_key_or_type(hostkeys, NULL, keytype, 415 found) == HOST_FOUND); 416} 417 418static int 419write_host_entry(FILE *f, const char *host, const char *ip, 420 const struct sshkey *key, int store_hash) 421{ 422 int r, success = 0; 423 char *hashed_host = NULL, *lhost; 424 425 lhost = xstrdup(host); 426 lowercase(lhost); 427 428 if (store_hash) { 429 if ((hashed_host = host_hash(lhost, NULL, 0)) == NULL) { 430 error("%s: host_hash failed", __func__); 431 free(lhost); 432 return 0; 433 } 434 fprintf(f, "%s ", hashed_host); 435 } else if (ip != NULL) 436 fprintf(f, "%s,%s ", lhost, ip); 437 else { 438 fprintf(f, "%s ", lhost); 439 } 440 free(lhost); 441 if ((r = sshkey_write(key, f)) == 0) 442 success = 1; 443 else 444 error("%s: sshkey_write failed: %s", __func__, ssh_err(r)); 445 fputc('\n', f); 446 return success; 447} 448 449/* 450 * Appends an entry to the host file. Returns false if the entry could not 451 * be appended. 452 */ 453int 454add_host_to_hostfile(const char *filename, const char *host, 455 const struct sshkey *key, int store_hash) 456{ 457 FILE *f; 458 int success; 459 460 if (key == NULL) 461 return 1; /* XXX ? */ 462 f = fopen(filename, "a"); 463 if (!f) 464 return 0; 465 success = write_host_entry(f, host, NULL, key, store_hash); 466 fclose(f); 467 return success; 468} 469 470struct host_delete_ctx { 471 FILE *out; 472 int quiet; 473 const char *host; 474 int *skip_keys; /* XXX split for host/ip? might want to ensure both */ 475 struct sshkey * const *keys; 476 size_t nkeys; 477 int modified; 478}; 479 480static int 481host_delete(struct hostkey_foreach_line *l, void *_ctx) 482{ 483 struct host_delete_ctx *ctx = (struct host_delete_ctx *)_ctx; 484 int loglevel = ctx->quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE; 485 size_t i; 486 487 if (l->status == HKF_STATUS_MATCHED) { 488 if (l->marker != MRK_NONE) { 489 /* Don't remove CA and revocation lines */ 490 fprintf(ctx->out, "%s\n", l->line); 491 return 0; 492 } 493 494 /* XXX might need a knob for this later */ 495 /* Don't remove RSA1 keys */ 496 if (l->key->type == KEY_RSA1) { 497 fprintf(ctx->out, "%s\n", l->line); 498 return 0; 499 } 500 501 /* 502 * If this line contains one of the keys that we will be 503 * adding later, then don't change it and mark the key for 504 * skipping. 505 */ 506 for (i = 0; i < ctx->nkeys; i++) { 507 if (sshkey_equal(ctx->keys[i], l->key)) { 508 ctx->skip_keys[i] = 1; 509 fprintf(ctx->out, "%s\n", l->line); 510 debug3("%s: %s key already at %s:%ld", __func__, 511 sshkey_type(l->key), l->path, l->linenum); 512 return 0; 513 } 514 } 515 516 /* 517 * Hostname matches and has no CA/revoke marker, delete it 518 * by *not* writing the line to ctx->out. 519 */ 520 do_log2(loglevel, "%s%s%s:%ld: Removed %s key for host %s", 521 ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "", 522 l->path, l->linenum, sshkey_type(l->key), ctx->host); 523 ctx->modified = 1; 524 return 0; 525 } 526 /* Retain non-matching hosts and invalid lines when deleting */ 527 if (l->status == HKF_STATUS_INVALID) { 528 do_log2(loglevel, "%s%s%s:%ld: invalid known_hosts entry", 529 ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "", 530 l->path, l->linenum); 531 } 532 fprintf(ctx->out, "%s\n", l->line); 533 return 0; 534} 535 536int 537hostfile_replace_entries(const char *filename, const char *host, const char *ip, 538 struct sshkey **keys, size_t nkeys, int store_hash, int quiet, int hash_alg) 539{ 540 int r, fd, oerrno = 0; 541 int loglevel = quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE; 542 struct host_delete_ctx ctx; 543 char *fp, *temp = NULL, *back = NULL; 544 mode_t omask; 545 size_t i; 546 547 omask = umask(077); 548 549 memset(&ctx, 0, sizeof(ctx)); 550 ctx.host = host; 551 ctx.quiet = quiet; 552 if ((ctx.skip_keys = calloc(nkeys, sizeof(*ctx.skip_keys))) == NULL) 553 return SSH_ERR_ALLOC_FAIL; 554 ctx.keys = keys; 555 ctx.nkeys = nkeys; 556 ctx.modified = 0; 557 558 /* 559 * Prepare temporary file for in-place deletion. 560 */ 561 if ((r = asprintf(&temp, "%s.XXXXXXXXXXX", filename)) < 0 || 562 (r = asprintf(&back, "%s.old", filename)) < 0) { 563 r = SSH_ERR_ALLOC_FAIL; 564 goto fail; 565 } 566 567 if ((fd = mkstemp(temp)) == -1) { 568 oerrno = errno; 569 error("%s: mkstemp: %s", __func__, strerror(oerrno)); 570 r = SSH_ERR_SYSTEM_ERROR; 571 goto fail; 572 } 573 if ((ctx.out = fdopen(fd, "w")) == NULL) { 574 oerrno = errno; 575 close(fd); 576 error("%s: fdopen: %s", __func__, strerror(oerrno)); 577 r = SSH_ERR_SYSTEM_ERROR; 578 goto fail; 579 } 580 581 /* Remove all entries for the specified host from the file */ 582 if ((r = hostkeys_foreach(filename, host_delete, &ctx, host, ip, 583 HKF_WANT_PARSE_KEY)) != 0) { 584 error("%s: hostkeys_foreach failed: %s", __func__, ssh_err(r)); 585 goto fail; 586 } 587 588 /* Add the requested keys */ 589 for (i = 0; i < nkeys; i++) { 590 if (ctx.skip_keys[i]) 591 continue; 592 if ((fp = sshkey_fingerprint(keys[i], hash_alg, 593 SSH_FP_DEFAULT)) == NULL) { 594 r = SSH_ERR_ALLOC_FAIL; 595 goto fail; 596 } 597 do_log2(loglevel, "%s%sAdding new key for %s to %s: %s %s", 598 quiet ? __func__ : "", quiet ? ": " : "", host, filename, 599 sshkey_ssh_name(keys[i]), fp); 600 free(fp); 601 if (!write_host_entry(ctx.out, host, ip, keys[i], store_hash)) { 602 r = SSH_ERR_INTERNAL_ERROR; 603 goto fail; 604 } 605 ctx.modified = 1; 606 } 607 fclose(ctx.out); 608 ctx.out = NULL; 609 610 if (ctx.modified) { 611 /* Backup the original file and replace it with the temporary */ 612 if (unlink(back) == -1 && errno != ENOENT) { 613 oerrno = errno; 614 error("%s: unlink %.100s: %s", __func__, 615 back, strerror(errno)); 616 r = SSH_ERR_SYSTEM_ERROR; 617 goto fail; 618 } 619 if (link(filename, back) == -1) { 620 oerrno = errno; 621 error("%s: link %.100s to %.100s: %s", __func__, 622 filename, back, strerror(errno)); 623 r = SSH_ERR_SYSTEM_ERROR; 624 goto fail; 625 } 626 if (rename(temp, filename) == -1) { 627 oerrno = errno; 628 error("%s: rename \"%s\" to \"%s\": %s", __func__, 629 temp, filename, strerror(errno)); 630 r = SSH_ERR_SYSTEM_ERROR; 631 goto fail; 632 } 633 } else { 634 /* No changes made; just delete the temporary file */ 635 if (unlink(temp) != 0) 636 error("%s: unlink \"%s\": %s", __func__, 637 temp, strerror(errno)); 638 } 639 640 /* success */ 641 r = 0; 642 fail: 643 if (temp != NULL && r != 0) 644 unlink(temp); 645 free(temp); 646 free(back); 647 if (ctx.out != NULL) 648 fclose(ctx.out); 649 free(ctx.skip_keys); 650 umask(omask); 651 if (r == SSH_ERR_SYSTEM_ERROR) 652 errno = oerrno; 653 return r; 654} 655 656static int 657match_maybe_hashed(const char *host, const char *names, int *was_hashed) 658{ 659 int hashed = *names == HASH_DELIM; 660 const char *hashed_host; 661 size_t nlen = strlen(names); 662 663 if (was_hashed != NULL) 664 *was_hashed = hashed; 665 if (hashed) { 666 if ((hashed_host = host_hash(host, names, nlen)) == NULL) 667 return -1; 668 return nlen == strlen(hashed_host) && 669 strncmp(hashed_host, names, nlen) == 0; 670 } 671 return match_hostname(host, names) == 1; 672} 673 674int 675hostkeys_foreach(const char *path, hostkeys_foreach_fn *callback, void *ctx, 676 const char *host, const char *ip, u_int options) 677{ 678 FILE *f; 679 char line[8192], oline[8192], ktype[128]; 680 u_long linenum = 0; 681 char *cp, *cp2; 682 u_int kbits; 683 int hashed; 684 int s, r = 0; 685 struct hostkey_foreach_line lineinfo; 686 size_t l; 687 688 memset(&lineinfo, 0, sizeof(lineinfo)); 689 if (host == NULL && (options & HKF_WANT_MATCH) != 0) 690 return SSH_ERR_INVALID_ARGUMENT; 691 if ((f = fopen(path, "r")) == NULL) 692 return SSH_ERR_SYSTEM_ERROR; 693 694 debug3("%s: reading file \"%s\"", __func__, path); 695 while (read_keyfile_line(f, path, line, sizeof(line), &linenum) == 0) { 696 line[strcspn(line, "\n")] = '\0'; 697 strlcpy(oline, line, sizeof(oline)); 698 699 sshkey_free(lineinfo.key); 700 memset(&lineinfo, 0, sizeof(lineinfo)); 701 lineinfo.path = path; 702 lineinfo.linenum = linenum; 703 lineinfo.line = oline; 704 lineinfo.marker = MRK_NONE; 705 lineinfo.status = HKF_STATUS_OK; 706 lineinfo.keytype = KEY_UNSPEC; 707 708 /* Skip any leading whitespace, comments and empty lines. */ 709 for (cp = line; *cp == ' ' || *cp == '\t'; cp++) 710 ; 711 if (!*cp || *cp == '#' || *cp == '\n') { 712 if ((options & HKF_WANT_MATCH) == 0) { 713 lineinfo.status = HKF_STATUS_COMMENT; 714 if ((r = callback(&lineinfo, ctx)) != 0) 715 break; 716 } 717 continue; 718 } 719 720 if ((lineinfo.marker = check_markers(&cp)) == MRK_ERROR) { 721 verbose("%s: invalid marker at %s:%lu", 722 __func__, path, linenum); 723 if ((options & HKF_WANT_MATCH) == 0) 724 goto bad; 725 continue; 726 } 727 728 /* Find the end of the host name portion. */ 729 for (cp2 = cp; *cp2 && *cp2 != ' ' && *cp2 != '\t'; cp2++) 730 ; 731 lineinfo.hosts = cp; 732 *cp2++ = '\0'; 733 734 /* Check if the host name matches. */ 735 if (host != NULL) { 736 if ((s = match_maybe_hashed(host, lineinfo.hosts, 737 &hashed)) == -1) { 738 debug2("%s: %s:%ld: bad host hash \"%.32s\"", 739 __func__, path, linenum, lineinfo.hosts); 740 goto bad; 741 } 742 if (s == 1) { 743 lineinfo.status = HKF_STATUS_MATCHED; 744 lineinfo.match |= HKF_MATCH_HOST | 745 (hashed ? HKF_MATCH_HOST_HASHED : 0); 746 } 747 /* Try matching IP address if supplied */ 748 if (ip != NULL) { 749 if ((s = match_maybe_hashed(ip, lineinfo.hosts, 750 &hashed)) == -1) { 751 debug2("%s: %s:%ld: bad ip hash " 752 "\"%.32s\"", __func__, path, 753 linenum, lineinfo.hosts); 754 goto bad; 755 } 756 if (s == 1) { 757 lineinfo.status = HKF_STATUS_MATCHED; 758 lineinfo.match |= HKF_MATCH_IP | 759 (hashed ? HKF_MATCH_IP_HASHED : 0); 760 } 761 } 762 /* 763 * Skip this line if host matching requested and 764 * neither host nor address matched. 765 */ 766 if ((options & HKF_WANT_MATCH) != 0 && 767 lineinfo.status != HKF_STATUS_MATCHED) 768 continue; 769 } 770 771 /* Got a match. Skip host name and any following whitespace */ 772 for (; *cp2 == ' ' || *cp2 == '\t'; cp2++) 773 ; 774 if (*cp2 == '\0' || *cp2 == '#') { 775 debug2("%s:%ld: truncated before key type", 776 path, linenum); 777 goto bad; 778 } 779 lineinfo.rawkey = cp = cp2; 780 781 if ((options & HKF_WANT_PARSE_KEY) != 0) { 782 /* 783 * Extract the key from the line. This will skip 784 * any leading whitespace. Ignore badly formatted 785 * lines. 786 */ 787 if ((lineinfo.key = sshkey_new(KEY_UNSPEC)) == NULL) { 788 error("%s: sshkey_new failed", __func__); 789 r = SSH_ERR_ALLOC_FAIL; 790 break; 791 } 792 if (!hostfile_read_key(&cp, &kbits, lineinfo.key)) { 793#ifdef WITH_SSH1 794 sshkey_free(lineinfo.key); 795 lineinfo.key = sshkey_new(KEY_RSA1); 796 if (lineinfo.key == NULL) { 797 error("%s: sshkey_new fail", __func__); 798 r = SSH_ERR_ALLOC_FAIL; 799 break; 800 } 801 if (!hostfile_read_key(&cp, &kbits, 802 lineinfo.key)) 803 goto bad; 804#else 805 goto bad; 806#endif 807 } 808 lineinfo.keytype = lineinfo.key->type; 809 lineinfo.comment = cp; 810 } else { 811 /* Extract and parse key type */ 812 l = strcspn(lineinfo.rawkey, " \t"); 813 if (l <= 1 || l >= sizeof(ktype) || 814 lineinfo.rawkey[l] == '\0') 815 goto bad; 816 memcpy(ktype, lineinfo.rawkey, l); 817 ktype[l] = '\0'; 818 lineinfo.keytype = sshkey_type_from_name(ktype); 819 820 /* 821 * Assume RSA1 if the first component is a short 822 * decimal number. 823 */ 824 if (lineinfo.keytype == KEY_UNSPEC && l < 8 && 825 strspn(ktype, "0123456789") == l) 826 lineinfo.keytype = KEY_RSA1; 827 828 /* 829 * Check that something other than whitespace follows 830 * the key type. This won't catch all corruption, but 831 * it does catch trivial truncation. 832 */ 833 cp2 += l; /* Skip past key type */ 834 for (; *cp2 == ' ' || *cp2 == '\t'; cp2++) 835 ; 836 if (*cp2 == '\0' || *cp2 == '#') { 837 debug2("%s:%ld: truncated after key type", 838 path, linenum); 839 lineinfo.keytype = KEY_UNSPEC; 840 } 841 if (lineinfo.keytype == KEY_UNSPEC) { 842 bad: 843 sshkey_free(lineinfo.key); 844 lineinfo.key = NULL; 845 lineinfo.status = HKF_STATUS_INVALID; 846 if ((r = callback(&lineinfo, ctx)) != 0) 847 break; 848 continue; 849 } 850 } 851 if ((r = callback(&lineinfo, ctx)) != 0) 852 break; 853 } 854 sshkey_free(lineinfo.key); 855 fclose(f); 856 return r; 857} 858