1/* $OpenBSD: hostfile.c,v 1.95 2023/02/21 06:48:18 dtucker 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 "pathnames.h" 61#include "ssherr.h" 62#include "digest.h" 63#include "hmac.h" 64#include "sshbuf.h" 65 66/* XXX hmac is too easy to dictionary attack; use bcrypt? */ 67 68static int 69extract_salt(const char *s, u_int l, u_char *salt, size_t salt_len) 70{ 71 char *p, *b64salt; 72 u_int b64len; 73 int ret; 74 75 if (l < sizeof(HASH_MAGIC) - 1) { 76 debug2("extract_salt: string too short"); 77 return (-1); 78 } 79 if (strncmp(s, HASH_MAGIC, sizeof(HASH_MAGIC) - 1) != 0) { 80 debug2("extract_salt: invalid magic identifier"); 81 return (-1); 82 } 83 s += sizeof(HASH_MAGIC) - 1; 84 l -= sizeof(HASH_MAGIC) - 1; 85 if ((p = memchr(s, HASH_DELIM, l)) == NULL) { 86 debug2("extract_salt: missing salt termination character"); 87 return (-1); 88 } 89 90 b64len = p - s; 91 /* Sanity check */ 92 if (b64len == 0 || b64len > 1024) { 93 debug2("extract_salt: bad encoded salt length %u", b64len); 94 return (-1); 95 } 96 b64salt = xmalloc(1 + b64len); 97 memcpy(b64salt, s, b64len); 98 b64salt[b64len] = '\0'; 99 100 ret = __b64_pton(b64salt, salt, salt_len); 101 free(b64salt); 102 if (ret == -1) { 103 debug2("extract_salt: salt decode error"); 104 return (-1); 105 } 106 if (ret != (int)ssh_hmac_bytes(SSH_DIGEST_SHA1)) { 107 debug2("extract_salt: expected salt len %zd, got %d", 108 ssh_hmac_bytes(SSH_DIGEST_SHA1), ret); 109 return (-1); 110 } 111 112 return (0); 113} 114 115char * 116host_hash(const char *host, const char *name_from_hostfile, u_int src_len) 117{ 118 struct ssh_hmac_ctx *ctx; 119 u_char salt[256], result[256]; 120 char uu_salt[512], uu_result[512]; 121 char *encoded = NULL; 122 u_int len; 123 124 len = ssh_digest_bytes(SSH_DIGEST_SHA1); 125 126 if (name_from_hostfile == NULL) { 127 /* Create new salt */ 128 arc4random_buf(salt, len); 129 } else { 130 /* Extract salt from known host entry */ 131 if (extract_salt(name_from_hostfile, src_len, salt, 132 sizeof(salt)) == -1) 133 return (NULL); 134 } 135 136 if ((ctx = ssh_hmac_start(SSH_DIGEST_SHA1)) == NULL || 137 ssh_hmac_init(ctx, salt, len) < 0 || 138 ssh_hmac_update(ctx, host, strlen(host)) < 0 || 139 ssh_hmac_final(ctx, result, sizeof(result))) 140 fatal_f("ssh_hmac failed"); 141 ssh_hmac_free(ctx); 142 143 if (__b64_ntop(salt, len, uu_salt, sizeof(uu_salt)) == -1 || 144 __b64_ntop(result, len, uu_result, sizeof(uu_result)) == -1) 145 fatal_f("__b64_ntop failed"); 146 xasprintf(&encoded, "%s%s%c%s", HASH_MAGIC, uu_salt, HASH_DELIM, 147 uu_result); 148 149 return (encoded); 150} 151 152/* 153 * Parses an RSA (number of bits, e, n) or DSA key from a string. Moves the 154 * pointer over the key. Skips any whitespace at the beginning and at end. 155 */ 156 157int 158hostfile_read_key(char **cpp, u_int *bitsp, struct sshkey *ret) 159{ 160 char *cp; 161 162 /* Skip leading whitespace. */ 163 for (cp = *cpp; *cp == ' ' || *cp == '\t'; cp++) 164 ; 165 166 if (sshkey_read(ret, &cp) != 0) 167 return 0; 168 169 /* Skip trailing whitespace. */ 170 for (; *cp == ' ' || *cp == '\t'; cp++) 171 ; 172 173 /* Return results. */ 174 *cpp = cp; 175 if (bitsp != NULL) 176 *bitsp = sshkey_size(ret); 177 return 1; 178} 179 180static HostkeyMarker 181check_markers(char **cpp) 182{ 183 char marker[32], *sp, *cp = *cpp; 184 int ret = MRK_NONE; 185 186 while (*cp == '@') { 187 /* Only one marker is allowed */ 188 if (ret != MRK_NONE) 189 return MRK_ERROR; 190 /* Markers are terminated by whitespace */ 191 if ((sp = strchr(cp, ' ')) == NULL && 192 (sp = strchr(cp, '\t')) == NULL) 193 return MRK_ERROR; 194 /* Extract marker for comparison */ 195 if (sp <= cp + 1 || sp >= cp + sizeof(marker)) 196 return MRK_ERROR; 197 memcpy(marker, cp, sp - cp); 198 marker[sp - cp] = '\0'; 199 if (strcmp(marker, CA_MARKER) == 0) 200 ret = MRK_CA; 201 else if (strcmp(marker, REVOKE_MARKER) == 0) 202 ret = MRK_REVOKE; 203 else 204 return MRK_ERROR; 205 206 /* Skip past marker and any whitespace that follows it */ 207 cp = sp; 208 for (; *cp == ' ' || *cp == '\t'; cp++) 209 ; 210 } 211 *cpp = cp; 212 return ret; 213} 214 215struct hostkeys * 216init_hostkeys(void) 217{ 218 struct hostkeys *ret = xcalloc(1, sizeof(*ret)); 219 220 ret->entries = NULL; 221 return ret; 222} 223 224struct load_callback_ctx { 225 const char *host; 226 u_long num_loaded; 227 struct hostkeys *hostkeys; 228}; 229 230static int 231record_hostkey(struct hostkey_foreach_line *l, void *_ctx) 232{ 233 struct load_callback_ctx *ctx = (struct load_callback_ctx *)_ctx; 234 struct hostkeys *hostkeys = ctx->hostkeys; 235 struct hostkey_entry *tmp; 236 237 if (l->status == HKF_STATUS_INVALID) { 238 /* XXX make this verbose() in the future */ 239 debug("%s:%ld: parse error in hostkeys file", 240 l->path, l->linenum); 241 return 0; 242 } 243 244 debug3_f("found %skey type %s in file %s:%lu", 245 l->marker == MRK_NONE ? "" : 246 (l->marker == MRK_CA ? "ca " : "revoked "), 247 sshkey_type(l->key), l->path, l->linenum); 248 if ((tmp = recallocarray(hostkeys->entries, hostkeys->num_entries, 249 hostkeys->num_entries + 1, sizeof(*hostkeys->entries))) == NULL) 250 return SSH_ERR_ALLOC_FAIL; 251 hostkeys->entries = tmp; 252 hostkeys->entries[hostkeys->num_entries].host = xstrdup(ctx->host); 253 hostkeys->entries[hostkeys->num_entries].file = xstrdup(l->path); 254 hostkeys->entries[hostkeys->num_entries].line = l->linenum; 255 hostkeys->entries[hostkeys->num_entries].key = l->key; 256 l->key = NULL; /* steal it */ 257 hostkeys->entries[hostkeys->num_entries].marker = l->marker; 258 hostkeys->entries[hostkeys->num_entries].note = l->note; 259 hostkeys->num_entries++; 260 ctx->num_loaded++; 261 262 return 0; 263} 264 265void 266load_hostkeys_file(struct hostkeys *hostkeys, const char *host, 267 const char *path, FILE *f, u_int note) 268{ 269 int r; 270 struct load_callback_ctx ctx; 271 272 ctx.host = host; 273 ctx.num_loaded = 0; 274 ctx.hostkeys = hostkeys; 275 276 if ((r = hostkeys_foreach_file(path, f, record_hostkey, &ctx, host, 277 NULL, HKF_WANT_MATCH|HKF_WANT_PARSE_KEY, note)) != 0) { 278 if (r != SSH_ERR_SYSTEM_ERROR && errno != ENOENT) 279 debug_fr(r, "hostkeys_foreach failed for %s", path); 280 } 281 if (ctx.num_loaded != 0) 282 debug3_f("loaded %lu keys from %s", ctx.num_loaded, host); 283} 284 285void 286load_hostkeys(struct hostkeys *hostkeys, const char *host, const char *path, 287 u_int note) 288{ 289 FILE *f; 290 291 if ((f = fopen(path, "r")) == NULL) { 292 debug_f("fopen %s: %s", path, strerror(errno)); 293 return; 294 } 295 296 load_hostkeys_file(hostkeys, host, path, f, note); 297 fclose(f); 298} 299 300void 301free_hostkeys(struct hostkeys *hostkeys) 302{ 303 u_int i; 304 305 for (i = 0; i < hostkeys->num_entries; i++) { 306 free(hostkeys->entries[i].host); 307 free(hostkeys->entries[i].file); 308 sshkey_free(hostkeys->entries[i].key); 309 explicit_bzero(hostkeys->entries + i, sizeof(*hostkeys->entries)); 310 } 311 free(hostkeys->entries); 312 freezero(hostkeys, sizeof(*hostkeys)); 313} 314 315static int 316check_key_not_revoked(struct hostkeys *hostkeys, struct sshkey *k) 317{ 318 int is_cert = sshkey_is_cert(k); 319 u_int i; 320 321 for (i = 0; i < hostkeys->num_entries; i++) { 322 if (hostkeys->entries[i].marker != MRK_REVOKE) 323 continue; 324 if (sshkey_equal_public(k, hostkeys->entries[i].key)) 325 return -1; 326 if (is_cert && k != NULL && 327 sshkey_equal_public(k->cert->signature_key, 328 hostkeys->entries[i].key)) 329 return -1; 330 } 331 return 0; 332} 333 334/* 335 * Match keys against a specified key, or look one up by key type. 336 * 337 * If looking for a keytype (key == NULL) and one is found then return 338 * HOST_FOUND, otherwise HOST_NEW. 339 * 340 * If looking for a key (key != NULL): 341 * 1. If the key is a cert and a matching CA is found, return HOST_OK 342 * 2. If the key is not a cert and a matching key is found, return HOST_OK 343 * 3. If no key matches but a key with a different type is found, then 344 * return HOST_CHANGED 345 * 4. If no matching keys are found, then return HOST_NEW. 346 * 347 * Finally, check any found key is not revoked. 348 */ 349static HostStatus 350check_hostkeys_by_key_or_type(struct hostkeys *hostkeys, 351 struct sshkey *k, int keytype, int nid, const struct hostkey_entry **found) 352{ 353 u_int i; 354 HostStatus end_return = HOST_NEW; 355 int want_cert = sshkey_is_cert(k); 356 HostkeyMarker want_marker = want_cert ? MRK_CA : MRK_NONE; 357 358 if (found != NULL) 359 *found = NULL; 360 361 for (i = 0; i < hostkeys->num_entries; i++) { 362 if (hostkeys->entries[i].marker != want_marker) 363 continue; 364 if (k == NULL) { 365 if (hostkeys->entries[i].key->type != keytype) 366 continue; 367 if (nid != -1 && 368 sshkey_type_plain(keytype) == KEY_ECDSA && 369 hostkeys->entries[i].key->ecdsa_nid != nid) 370 continue; 371 end_return = HOST_FOUND; 372 if (found != NULL) 373 *found = hostkeys->entries + i; 374 k = hostkeys->entries[i].key; 375 break; 376 } 377 if (want_cert) { 378 if (sshkey_equal_public(k->cert->signature_key, 379 hostkeys->entries[i].key)) { 380 /* A matching CA exists */ 381 end_return = HOST_OK; 382 if (found != NULL) 383 *found = hostkeys->entries + i; 384 break; 385 } 386 } else { 387 if (sshkey_equal(k, hostkeys->entries[i].key)) { 388 end_return = HOST_OK; 389 if (found != NULL) 390 *found = hostkeys->entries + i; 391 break; 392 } 393 /* A non-matching key exists */ 394 end_return = HOST_CHANGED; 395 if (found != NULL) 396 *found = hostkeys->entries + i; 397 } 398 } 399 if (check_key_not_revoked(hostkeys, k) != 0) { 400 end_return = HOST_REVOKED; 401 if (found != NULL) 402 *found = NULL; 403 } 404 return end_return; 405} 406 407HostStatus 408check_key_in_hostkeys(struct hostkeys *hostkeys, struct sshkey *key, 409 const struct hostkey_entry **found) 410{ 411 if (key == NULL) 412 fatal("no key to look up"); 413 return check_hostkeys_by_key_or_type(hostkeys, key, 0, -1, found); 414} 415 416int 417lookup_key_in_hostkeys_by_type(struct hostkeys *hostkeys, int keytype, int nid, 418 const struct hostkey_entry **found) 419{ 420 return (check_hostkeys_by_key_or_type(hostkeys, NULL, keytype, nid, 421 found) == HOST_FOUND); 422} 423 424int 425lookup_marker_in_hostkeys(struct hostkeys *hostkeys, int want_marker) 426{ 427 u_int i; 428 429 for (i = 0; i < hostkeys->num_entries; i++) { 430 if (hostkeys->entries[i].marker == (HostkeyMarker)want_marker) 431 return 1; 432 } 433 return 0; 434} 435 436static int 437write_host_entry(FILE *f, const char *host, const char *ip, 438 const struct sshkey *key, int store_hash) 439{ 440 int r, success = 0; 441 char *hashed_host = NULL, *lhost; 442 443 lhost = xstrdup(host); 444 lowercase(lhost); 445 446 if (store_hash) { 447 if ((hashed_host = host_hash(lhost, NULL, 0)) == NULL) { 448 error_f("host_hash failed"); 449 free(lhost); 450 return 0; 451 } 452 fprintf(f, "%s ", hashed_host); 453 } else if (ip != NULL) 454 fprintf(f, "%s,%s ", lhost, ip); 455 else { 456 fprintf(f, "%s ", lhost); 457 } 458 free(hashed_host); 459 free(lhost); 460 if ((r = sshkey_write(key, f)) == 0) 461 success = 1; 462 else 463 error_fr(r, "sshkey_write"); 464 fputc('\n', f); 465 /* If hashing is enabled, the IP address needs to go on its own line */ 466 if (success && store_hash && ip != NULL) 467 success = write_host_entry(f, ip, NULL, key, 1); 468 return success; 469} 470 471/* 472 * Create user ~/.ssh directory if it doesn't exist and we want to write to it. 473 * If notify is set, a message will be emitted if the directory is created. 474 */ 475void 476hostfile_create_user_ssh_dir(const char *filename, int notify) 477{ 478 char *dotsshdir = NULL, *p; 479 size_t len; 480 struct stat st; 481 482 if ((p = strrchr(filename, '/')) == NULL) 483 return; 484 len = p - filename; 485 dotsshdir = tilde_expand_filename("~/" _PATH_SSH_USER_DIR, getuid()); 486 if (strlen(dotsshdir) > len || strncmp(filename, dotsshdir, len) != 0) 487 goto out; /* not ~/.ssh prefixed */ 488 if (stat(dotsshdir, &st) == 0) 489 goto out; /* dir already exists */ 490 else if (errno != ENOENT) 491 error("Could not stat %s: %s", dotsshdir, strerror(errno)); 492 else { 493#ifdef WITH_SELINUX 494 ssh_selinux_setfscreatecon(dotsshdir); 495#endif 496 if (mkdir(dotsshdir, 0700) == -1) 497 error("Could not create directory '%.200s' (%s).", 498 dotsshdir, strerror(errno)); 499 else if (notify) 500 logit("Created directory '%s'.", dotsshdir); 501#ifdef WITH_SELINUX 502 ssh_selinux_setfscreatecon(NULL); 503#endif 504 } 505 out: 506 free(dotsshdir); 507} 508 509/* 510 * Appends an entry to the host file. Returns false if the entry could not 511 * be appended. 512 */ 513int 514add_host_to_hostfile(const char *filename, const char *host, 515 const struct sshkey *key, int store_hash) 516{ 517 FILE *f; 518 int success, addnl = 0; 519 520 if (key == NULL) 521 return 1; /* XXX ? */ 522 hostfile_create_user_ssh_dir(filename, 0); 523 f = fopen(filename, "a+"); 524 if (!f) 525 return 0; 526 /* Make sure we have a terminating newline. */ 527 if (fseek(f, -1L, SEEK_END) == 0 && fgetc(f) != '\n') 528 addnl = 1; 529 if (fseek(f, 0L, SEEK_END) != 0 || (addnl && fputc('\n', f) != '\n')) { 530 error("Failed to add terminating newline to %s: %s", 531 filename, strerror(errno)); 532 fclose(f); 533 return 0; 534 } 535 success = write_host_entry(f, host, NULL, key, store_hash); 536 fclose(f); 537 return success; 538} 539 540struct host_delete_ctx { 541 FILE *out; 542 int quiet; 543 const char *host, *ip; 544 u_int *match_keys; /* mask of HKF_MATCH_* for this key */ 545 struct sshkey * const *keys; 546 size_t nkeys; 547 int modified; 548}; 549 550static int 551host_delete(struct hostkey_foreach_line *l, void *_ctx) 552{ 553 struct host_delete_ctx *ctx = (struct host_delete_ctx *)_ctx; 554 int loglevel = ctx->quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE; 555 size_t i; 556 557 /* Don't remove CA and revocation lines */ 558 if (l->status == HKF_STATUS_MATCHED && l->marker == MRK_NONE) { 559 /* 560 * If this line contains one of the keys that we will be 561 * adding later, then don't change it and mark the key for 562 * skipping. 563 */ 564 for (i = 0; i < ctx->nkeys; i++) { 565 if (!sshkey_equal(ctx->keys[i], l->key)) 566 continue; 567 ctx->match_keys[i] |= l->match; 568 fprintf(ctx->out, "%s\n", l->line); 569 debug3_f("%s key already at %s:%ld", 570 sshkey_type(l->key), l->path, l->linenum); 571 return 0; 572 } 573 574 /* 575 * Hostname matches and has no CA/revoke marker, delete it 576 * by *not* writing the line to ctx->out. 577 */ 578 do_log2(loglevel, "%s%s%s:%ld: Removed %s key for host %s", 579 ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "", 580 l->path, l->linenum, sshkey_type(l->key), ctx->host); 581 ctx->modified = 1; 582 return 0; 583 } 584 /* Retain non-matching hosts and invalid lines when deleting */ 585 if (l->status == HKF_STATUS_INVALID) { 586 do_log2(loglevel, "%s%s%s:%ld: invalid known_hosts entry", 587 ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "", 588 l->path, l->linenum); 589 } 590 fprintf(ctx->out, "%s\n", l->line); 591 return 0; 592} 593 594int 595hostfile_replace_entries(const char *filename, const char *host, const char *ip, 596 struct sshkey **keys, size_t nkeys, int store_hash, int quiet, int hash_alg) 597{ 598 int r, fd, oerrno = 0; 599 int loglevel = quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE; 600 struct host_delete_ctx ctx; 601 char *fp, *temp = NULL, *back = NULL; 602 const char *what; 603 mode_t omask; 604 size_t i; 605 u_int want; 606 607 omask = umask(077); 608 609 memset(&ctx, 0, sizeof(ctx)); 610 ctx.host = host; 611 ctx.ip = ip; 612 ctx.quiet = quiet; 613 614 if ((ctx.match_keys = calloc(nkeys, sizeof(*ctx.match_keys))) == NULL) 615 return SSH_ERR_ALLOC_FAIL; 616 ctx.keys = keys; 617 ctx.nkeys = nkeys; 618 ctx.modified = 0; 619 620 /* 621 * Prepare temporary file for in-place deletion. 622 */ 623 if ((r = asprintf(&temp, "%s.XXXXXXXXXXX", filename)) == -1 || 624 (r = asprintf(&back, "%s.old", filename)) == -1) { 625 r = SSH_ERR_ALLOC_FAIL; 626 goto fail; 627 } 628 629 if ((fd = mkstemp(temp)) == -1) { 630 oerrno = errno; 631 error_f("mkstemp: %s", strerror(oerrno)); 632 r = SSH_ERR_SYSTEM_ERROR; 633 goto fail; 634 } 635 if ((ctx.out = fdopen(fd, "w")) == NULL) { 636 oerrno = errno; 637 close(fd); 638 error_f("fdopen: %s", strerror(oerrno)); 639 r = SSH_ERR_SYSTEM_ERROR; 640 goto fail; 641 } 642 643 /* Remove stale/mismatching entries for the specified host */ 644 if ((r = hostkeys_foreach(filename, host_delete, &ctx, host, ip, 645 HKF_WANT_PARSE_KEY, 0)) != 0) { 646 oerrno = errno; 647 error_fr(r, "hostkeys_foreach"); 648 goto fail; 649 } 650 651 /* Re-add the requested keys */ 652 want = HKF_MATCH_HOST | (ip == NULL ? 0 : HKF_MATCH_IP); 653 for (i = 0; i < nkeys; i++) { 654 if (keys[i] == NULL || (want & ctx.match_keys[i]) == want) 655 continue; 656 if ((fp = sshkey_fingerprint(keys[i], hash_alg, 657 SSH_FP_DEFAULT)) == NULL) { 658 r = SSH_ERR_ALLOC_FAIL; 659 goto fail; 660 } 661 /* write host/ip */ 662 what = ""; 663 if (ctx.match_keys[i] == 0) { 664 what = "Adding new key"; 665 if (!write_host_entry(ctx.out, host, ip, 666 keys[i], store_hash)) { 667 r = SSH_ERR_INTERNAL_ERROR; 668 goto fail; 669 } 670 } else if ((want & ~ctx.match_keys[i]) == HKF_MATCH_HOST) { 671 what = "Fixing match (hostname)"; 672 if (!write_host_entry(ctx.out, host, NULL, 673 keys[i], store_hash)) { 674 r = SSH_ERR_INTERNAL_ERROR; 675 goto fail; 676 } 677 } else if ((want & ~ctx.match_keys[i]) == HKF_MATCH_IP) { 678 what = "Fixing match (address)"; 679 if (!write_host_entry(ctx.out, ip, NULL, 680 keys[i], store_hash)) { 681 r = SSH_ERR_INTERNAL_ERROR; 682 goto fail; 683 } 684 } 685 do_log2(loglevel, "%s%s%s for %s%s%s to %s: %s %s", 686 quiet ? __func__ : "", quiet ? ": " : "", what, 687 host, ip == NULL ? "" : ",", ip == NULL ? "" : ip, filename, 688 sshkey_ssh_name(keys[i]), fp); 689 free(fp); 690 ctx.modified = 1; 691 } 692 fclose(ctx.out); 693 ctx.out = NULL; 694 695 if (ctx.modified) { 696 /* Backup the original file and replace it with the temporary */ 697 if (unlink(back) == -1 && errno != ENOENT) { 698 oerrno = errno; 699 error_f("unlink %.100s: %s", back, strerror(errno)); 700 r = SSH_ERR_SYSTEM_ERROR; 701 goto fail; 702 } 703 if (link(filename, back) == -1) { 704 oerrno = errno; 705 error_f("link %.100s to %.100s: %s", filename, 706 back, strerror(errno)); 707 r = SSH_ERR_SYSTEM_ERROR; 708 goto fail; 709 } 710 if (rename(temp, filename) == -1) { 711 oerrno = errno; 712 error_f("rename \"%s\" to \"%s\": %s", temp, 713 filename, strerror(errno)); 714 r = SSH_ERR_SYSTEM_ERROR; 715 goto fail; 716 } 717 } else { 718 /* No changes made; just delete the temporary file */ 719 if (unlink(temp) != 0) 720 error_f("unlink \"%s\": %s", temp, strerror(errno)); 721 } 722 723 /* success */ 724 r = 0; 725 fail: 726 if (temp != NULL && r != 0) 727 unlink(temp); 728 free(temp); 729 free(back); 730 if (ctx.out != NULL) 731 fclose(ctx.out); 732 free(ctx.match_keys); 733 umask(omask); 734 if (r == SSH_ERR_SYSTEM_ERROR) 735 errno = oerrno; 736 return r; 737} 738 739static int 740match_maybe_hashed(const char *host, const char *names, int *was_hashed) 741{ 742 int hashed = *names == HASH_DELIM, ret; 743 char *hashed_host = NULL; 744 size_t nlen = strlen(names); 745 746 if (was_hashed != NULL) 747 *was_hashed = hashed; 748 if (hashed) { 749 if ((hashed_host = host_hash(host, names, nlen)) == NULL) 750 return -1; 751 ret = (nlen == strlen(hashed_host) && 752 strncmp(hashed_host, names, nlen) == 0); 753 free(hashed_host); 754 return ret; 755 } 756 return match_hostname(host, names) == 1; 757} 758 759int 760hostkeys_foreach_file(const char *path, FILE *f, hostkeys_foreach_fn *callback, 761 void *ctx, const char *host, const char *ip, u_int options, u_int note) 762{ 763 char *line = NULL, ktype[128]; 764 u_long linenum = 0; 765 char *cp, *cp2; 766 u_int kbits; 767 int hashed; 768 int s, r = 0; 769 struct hostkey_foreach_line lineinfo; 770 size_t linesize = 0, l; 771 772 memset(&lineinfo, 0, sizeof(lineinfo)); 773 if (host == NULL && (options & HKF_WANT_MATCH) != 0) 774 return SSH_ERR_INVALID_ARGUMENT; 775 776 while (getline(&line, &linesize, f) != -1) { 777 linenum++; 778 line[strcspn(line, "\n")] = '\0'; 779 780 free(lineinfo.line); 781 sshkey_free(lineinfo.key); 782 memset(&lineinfo, 0, sizeof(lineinfo)); 783 lineinfo.path = path; 784 lineinfo.linenum = linenum; 785 lineinfo.line = xstrdup(line); 786 lineinfo.marker = MRK_NONE; 787 lineinfo.status = HKF_STATUS_OK; 788 lineinfo.keytype = KEY_UNSPEC; 789 lineinfo.note = note; 790 791 /* Skip any leading whitespace, comments and empty lines. */ 792 for (cp = line; *cp == ' ' || *cp == '\t'; cp++) 793 ; 794 if (!*cp || *cp == '#' || *cp == '\n') { 795 if ((options & HKF_WANT_MATCH) == 0) { 796 lineinfo.status = HKF_STATUS_COMMENT; 797 if ((r = callback(&lineinfo, ctx)) != 0) 798 break; 799 } 800 continue; 801 } 802 803 if ((lineinfo.marker = check_markers(&cp)) == MRK_ERROR) { 804 verbose_f("invalid marker at %s:%lu", path, linenum); 805 if ((options & HKF_WANT_MATCH) == 0) 806 goto bad; 807 continue; 808 } 809 810 /* Find the end of the host name portion. */ 811 for (cp2 = cp; *cp2 && *cp2 != ' ' && *cp2 != '\t'; cp2++) 812 ; 813 lineinfo.hosts = cp; 814 *cp2++ = '\0'; 815 816 /* Check if the host name matches. */ 817 if (host != NULL) { 818 if ((s = match_maybe_hashed(host, lineinfo.hosts, 819 &hashed)) == -1) { 820 debug2_f("%s:%ld: bad host hash \"%.32s\"", 821 path, linenum, lineinfo.hosts); 822 goto bad; 823 } 824 if (s == 1) { 825 lineinfo.status = HKF_STATUS_MATCHED; 826 lineinfo.match |= HKF_MATCH_HOST | 827 (hashed ? HKF_MATCH_HOST_HASHED : 0); 828 } 829 /* Try matching IP address if supplied */ 830 if (ip != NULL) { 831 if ((s = match_maybe_hashed(ip, lineinfo.hosts, 832 &hashed)) == -1) { 833 debug2_f("%s:%ld: bad ip hash " 834 "\"%.32s\"", path, linenum, 835 lineinfo.hosts); 836 goto bad; 837 } 838 if (s == 1) { 839 lineinfo.status = HKF_STATUS_MATCHED; 840 lineinfo.match |= HKF_MATCH_IP | 841 (hashed ? HKF_MATCH_IP_HASHED : 0); 842 } 843 } 844 /* 845 * Skip this line if host matching requested and 846 * neither host nor address matched. 847 */ 848 if ((options & HKF_WANT_MATCH) != 0 && 849 lineinfo.status != HKF_STATUS_MATCHED) 850 continue; 851 } 852 853 /* Got a match. Skip host name and any following whitespace */ 854 for (; *cp2 == ' ' || *cp2 == '\t'; cp2++) 855 ; 856 if (*cp2 == '\0' || *cp2 == '#') { 857 debug2("%s:%ld: truncated before key type", 858 path, linenum); 859 goto bad; 860 } 861 lineinfo.rawkey = cp = cp2; 862 863 if ((options & HKF_WANT_PARSE_KEY) != 0) { 864 /* 865 * Extract the key from the line. This will skip 866 * any leading whitespace. Ignore badly formatted 867 * lines. 868 */ 869 if ((lineinfo.key = sshkey_new(KEY_UNSPEC)) == NULL) { 870 error_f("sshkey_new failed"); 871 r = SSH_ERR_ALLOC_FAIL; 872 break; 873 } 874 if (!hostfile_read_key(&cp, &kbits, lineinfo.key)) { 875 goto bad; 876 } 877 lineinfo.keytype = lineinfo.key->type; 878 lineinfo.comment = cp; 879 } else { 880 /* Extract and parse key type */ 881 l = strcspn(lineinfo.rawkey, " \t"); 882 if (l <= 1 || l >= sizeof(ktype) || 883 lineinfo.rawkey[l] == '\0') 884 goto bad; 885 memcpy(ktype, lineinfo.rawkey, l); 886 ktype[l] = '\0'; 887 lineinfo.keytype = sshkey_type_from_name(ktype); 888 889 /* 890 * Assume legacy RSA1 if the first component is a short 891 * decimal number. 892 */ 893 if (lineinfo.keytype == KEY_UNSPEC && l < 8 && 894 strspn(ktype, "0123456789") == l) 895 goto bad; 896 897 /* 898 * Check that something other than whitespace follows 899 * the key type. This won't catch all corruption, but 900 * it does catch trivial truncation. 901 */ 902 cp2 += l; /* Skip past key type */ 903 for (; *cp2 == ' ' || *cp2 == '\t'; cp2++) 904 ; 905 if (*cp2 == '\0' || *cp2 == '#') { 906 debug2("%s:%ld: truncated after key type", 907 path, linenum); 908 lineinfo.keytype = KEY_UNSPEC; 909 } 910 if (lineinfo.keytype == KEY_UNSPEC) { 911 bad: 912 sshkey_free(lineinfo.key); 913 lineinfo.key = NULL; 914 lineinfo.status = HKF_STATUS_INVALID; 915 if ((r = callback(&lineinfo, ctx)) != 0) 916 break; 917 continue; 918 } 919 } 920 if ((r = callback(&lineinfo, ctx)) != 0) 921 break; 922 } 923 sshkey_free(lineinfo.key); 924 free(lineinfo.line); 925 free(line); 926 return r; 927} 928 929int 930hostkeys_foreach(const char *path, hostkeys_foreach_fn *callback, void *ctx, 931 const char *host, const char *ip, u_int options, u_int note) 932{ 933 FILE *f; 934 int r, oerrno; 935 936 if ((f = fopen(path, "r")) == NULL) 937 return SSH_ERR_SYSTEM_ERROR; 938 939 debug3_f("reading file \"%s\"", path); 940 r = hostkeys_foreach_file(path, f, callback, ctx, host, ip, 941 options, note); 942 oerrno = errno; 943 fclose(f); 944 errno = oerrno; 945 return r; 946} 947