1 /* $OpenBSD: hostfile.c,v 1.68 2017/03/10 04:26:06 djm 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
extract_salt(const char * s,u_int l,u_char * salt,size_t salt_len)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 *
host_hash(const char * host,const char * name_from_hostfile,u_int src_len)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
hostfile_read_key(char ** cpp,u_int * bitsp,struct sshkey * ret)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
check_markers(char ** cpp)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 *
init_hostkeys(void)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
record_hostkey(struct hostkey_foreach_line * l,void * _ctx)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
load_hostkeys(struct hostkeys * hostkeys,const char * host,const char * path)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
free_hostkeys(struct hostkeys * hostkeys)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
check_key_not_revoked(struct hostkeys * hostkeys,struct sshkey * k)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
check_hostkeys_by_key_or_type(struct hostkeys * hostkeys,struct sshkey * k,int keytype,const struct hostkey_entry ** found)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
check_key_in_hostkeys(struct hostkeys * hostkeys,struct sshkey * key,const struct hostkey_entry ** found)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
lookup_key_in_hostkeys_by_type(struct hostkeys * hostkeys,int keytype,const struct hostkey_entry ** found)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
write_host_entry(FILE * f,const char * host,const char * ip,const struct sshkey * key,int store_hash)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, *lhost;
423
424 lhost = xstrdup(host);
425 lowercase(lhost);
426
427 if (store_hash) {
428 if ((hashed_host = host_hash(lhost, NULL, 0)) == NULL) {
429 error("%s: host_hash failed", __func__);
430 free(lhost);
431 return 0;
432 }
433 fprintf(f, "%s ", hashed_host);
434 } else if (ip != NULL)
435 fprintf(f, "%s,%s ", lhost, ip);
436 else {
437 fprintf(f, "%s ", lhost);
438 }
439 free(lhost);
440 if ((r = sshkey_write(key, f)) == 0)
441 success = 1;
442 else
443 error("%s: sshkey_write failed: %s", __func__, ssh_err(r));
444 fputc('\n', f);
445 return success;
446 }
447
448 /*
449 * Appends an entry to the host file. Returns false if the entry could not
450 * be appended.
451 */
452 int
add_host_to_hostfile(const char * filename,const char * host,const struct sshkey * key,int store_hash)453 add_host_to_hostfile(const char *filename, const char *host,
454 const struct sshkey *key, int store_hash)
455 {
456 FILE *f;
457 int success;
458
459 if (key == NULL)
460 return 1; /* XXX ? */
461 f = fopen(filename, "a");
462 if (!f)
463 return 0;
464 success = write_host_entry(f, host, NULL, key, store_hash);
465 fclose(f);
466 return success;
467 }
468
469 struct host_delete_ctx {
470 FILE *out;
471 int quiet;
472 const char *host;
473 int *skip_keys; /* XXX split for host/ip? might want to ensure both */
474 struct sshkey * const *keys;
475 size_t nkeys;
476 int modified;
477 };
478
479 static int
host_delete(struct hostkey_foreach_line * l,void * _ctx)480 host_delete(struct hostkey_foreach_line *l, void *_ctx)
481 {
482 struct host_delete_ctx *ctx = (struct host_delete_ctx *)_ctx;
483 int loglevel = ctx->quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE;
484 size_t i;
485
486 if (l->status == HKF_STATUS_MATCHED) {
487 if (l->marker != MRK_NONE) {
488 /* Don't remove CA and revocation lines */
489 fprintf(ctx->out, "%s\n", l->line);
490 return 0;
491 }
492
493 /* XXX might need a knob for this later */
494 /* Don't remove RSA1 keys */
495 if (l->key->type == KEY_RSA1) {
496 fprintf(ctx->out, "%s\n", l->line);
497 return 0;
498 }
499
500 /*
501 * If this line contains one of the keys that we will be
502 * adding later, then don't change it and mark the key for
503 * skipping.
504 */
505 for (i = 0; i < ctx->nkeys; i++) {
506 if (sshkey_equal(ctx->keys[i], l->key)) {
507 ctx->skip_keys[i] = 1;
508 fprintf(ctx->out, "%s\n", l->line);
509 debug3("%s: %s key already at %s:%ld", __func__,
510 sshkey_type(l->key), l->path, l->linenum);
511 return 0;
512 }
513 }
514
515 /*
516 * Hostname matches and has no CA/revoke marker, delete it
517 * by *not* writing the line to ctx->out.
518 */
519 do_log2(loglevel, "%s%s%s:%ld: Removed %s key for host %s",
520 ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "",
521 l->path, l->linenum, sshkey_type(l->key), ctx->host);
522 ctx->modified = 1;
523 return 0;
524 }
525 /* Retain non-matching hosts and invalid lines when deleting */
526 if (l->status == HKF_STATUS_INVALID) {
527 do_log2(loglevel, "%s%s%s:%ld: invalid known_hosts entry",
528 ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "",
529 l->path, l->linenum);
530 }
531 fprintf(ctx->out, "%s\n", l->line);
532 return 0;
533 }
534
535 int
hostfile_replace_entries(const char * filename,const char * host,const char * ip,struct sshkey ** keys,size_t nkeys,int store_hash,int quiet,int hash_alg)536 hostfile_replace_entries(const char *filename, const char *host, const char *ip,
537 struct sshkey **keys, size_t nkeys, int store_hash, int quiet, int hash_alg)
538 {
539 int r, fd, oerrno = 0;
540 int loglevel = quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE;
541 struct host_delete_ctx ctx;
542 char *fp, *temp = NULL, *back = NULL;
543 mode_t omask;
544 size_t i;
545
546 omask = umask(077);
547
548 memset(&ctx, 0, sizeof(ctx));
549 ctx.host = host;
550 ctx.quiet = quiet;
551 if ((ctx.skip_keys = calloc(nkeys, sizeof(*ctx.skip_keys))) == NULL)
552 return SSH_ERR_ALLOC_FAIL;
553 ctx.keys = keys;
554 ctx.nkeys = nkeys;
555 ctx.modified = 0;
556
557 /*
558 * Prepare temporary file for in-place deletion.
559 */
560 if ((r = asprintf(&temp, "%s.XXXXXXXXXXX", filename)) < 0 ||
561 (r = asprintf(&back, "%s.old", filename)) < 0) {
562 r = SSH_ERR_ALLOC_FAIL;
563 goto fail;
564 }
565
566 if ((fd = mkstemp(temp)) == -1) {
567 oerrno = errno;
568 error("%s: mkstemp: %s", __func__, strerror(oerrno));
569 r = SSH_ERR_SYSTEM_ERROR;
570 goto fail;
571 }
572 if ((ctx.out = fdopen(fd, "w")) == NULL) {
573 oerrno = errno;
574 close(fd);
575 error("%s: fdopen: %s", __func__, strerror(oerrno));
576 r = SSH_ERR_SYSTEM_ERROR;
577 goto fail;
578 }
579
580 /* Remove all entries for the specified host from the file */
581 if ((r = hostkeys_foreach(filename, host_delete, &ctx, host, ip,
582 HKF_WANT_PARSE_KEY)) != 0) {
583 error("%s: hostkeys_foreach failed: %s", __func__, ssh_err(r));
584 goto fail;
585 }
586
587 /* Add the requested keys */
588 for (i = 0; i < nkeys; i++) {
589 if (ctx.skip_keys[i])
590 continue;
591 if ((fp = sshkey_fingerprint(keys[i], hash_alg,
592 SSH_FP_DEFAULT)) == NULL) {
593 r = SSH_ERR_ALLOC_FAIL;
594 goto fail;
595 }
596 do_log2(loglevel, "%s%sAdding new key for %s to %s: %s %s",
597 quiet ? __func__ : "", quiet ? ": " : "", host, filename,
598 sshkey_ssh_name(keys[i]), fp);
599 free(fp);
600 if (!write_host_entry(ctx.out, host, ip, keys[i], store_hash)) {
601 r = SSH_ERR_INTERNAL_ERROR;
602 goto fail;
603 }
604 ctx.modified = 1;
605 }
606 fclose(ctx.out);
607 ctx.out = NULL;
608
609 if (ctx.modified) {
610 /* Backup the original file and replace it with the temporary */
611 if (unlink(back) == -1 && errno != ENOENT) {
612 oerrno = errno;
613 error("%s: unlink %.100s: %s", __func__,
614 back, strerror(errno));
615 r = SSH_ERR_SYSTEM_ERROR;
616 goto fail;
617 }
618 if (link(filename, back) == -1) {
619 oerrno = errno;
620 error("%s: link %.100s to %.100s: %s", __func__,
621 filename, back, strerror(errno));
622 r = SSH_ERR_SYSTEM_ERROR;
623 goto fail;
624 }
625 if (rename(temp, filename) == -1) {
626 oerrno = errno;
627 error("%s: rename \"%s\" to \"%s\": %s", __func__,
628 temp, filename, strerror(errno));
629 r = SSH_ERR_SYSTEM_ERROR;
630 goto fail;
631 }
632 } else {
633 /* No changes made; just delete the temporary file */
634 if (unlink(temp) != 0)
635 error("%s: unlink \"%s\": %s", __func__,
636 temp, strerror(errno));
637 }
638
639 /* success */
640 r = 0;
641 fail:
642 if (temp != NULL && r != 0)
643 unlink(temp);
644 free(temp);
645 free(back);
646 if (ctx.out != NULL)
647 fclose(ctx.out);
648 free(ctx.skip_keys);
649 umask(omask);
650 if (r == SSH_ERR_SYSTEM_ERROR)
651 errno = oerrno;
652 return r;
653 }
654
655 static int
match_maybe_hashed(const char * host,const char * names,int * was_hashed)656 match_maybe_hashed(const char *host, const char *names, int *was_hashed)
657 {
658 int hashed = *names == HASH_DELIM;
659 const char *hashed_host;
660 size_t nlen = strlen(names);
661
662 if (was_hashed != NULL)
663 *was_hashed = hashed;
664 if (hashed) {
665 if ((hashed_host = host_hash(host, names, nlen)) == NULL)
666 return -1;
667 return nlen == strlen(hashed_host) &&
668 strncmp(hashed_host, names, nlen) == 0;
669 }
670 return match_hostname(host, names) == 1;
671 }
672
673 int
hostkeys_foreach(const char * path,hostkeys_foreach_fn * callback,void * ctx,const char * host,const char * ip,u_int options)674 hostkeys_foreach(const char *path, hostkeys_foreach_fn *callback, void *ctx,
675 const char *host, const char *ip, u_int options)
676 {
677 FILE *f;
678 char line[8192], oline[8192], ktype[128];
679 u_long linenum = 0;
680 char *cp, *cp2;
681 u_int kbits;
682 int hashed;
683 int s, r = 0;
684 struct hostkey_foreach_line lineinfo;
685 size_t l;
686
687 memset(&lineinfo, 0, sizeof(lineinfo));
688 if (host == NULL && (options & HKF_WANT_MATCH) != 0)
689 return SSH_ERR_INVALID_ARGUMENT;
690 if ((f = fopen(path, "r")) == NULL)
691 return SSH_ERR_SYSTEM_ERROR;
692
693 debug3("%s: reading file \"%s\"", __func__, path);
694 while (read_keyfile_line(f, path, line, sizeof(line), &linenum) == 0) {
695 line[strcspn(line, "\n")] = '\0';
696 strlcpy(oline, line, sizeof(oline));
697
698 sshkey_free(lineinfo.key);
699 memset(&lineinfo, 0, sizeof(lineinfo));
700 lineinfo.path = path;
701 lineinfo.linenum = linenum;
702 lineinfo.line = oline;
703 lineinfo.marker = MRK_NONE;
704 lineinfo.status = HKF_STATUS_OK;
705 lineinfo.keytype = KEY_UNSPEC;
706
707 /* Skip any leading whitespace, comments and empty lines. */
708 for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
709 ;
710 if (!*cp || *cp == '#' || *cp == '\n') {
711 if ((options & HKF_WANT_MATCH) == 0) {
712 lineinfo.status = HKF_STATUS_COMMENT;
713 if ((r = callback(&lineinfo, ctx)) != 0)
714 break;
715 }
716 continue;
717 }
718
719 if ((lineinfo.marker = check_markers(&cp)) == MRK_ERROR) {
720 verbose("%s: invalid marker at %s:%lu",
721 __func__, path, linenum);
722 if ((options & HKF_WANT_MATCH) == 0)
723 goto bad;
724 continue;
725 }
726
727 /* Find the end of the host name portion. */
728 for (cp2 = cp; *cp2 && *cp2 != ' ' && *cp2 != '\t'; cp2++)
729 ;
730 lineinfo.hosts = cp;
731 *cp2++ = '\0';
732
733 /* Check if the host name matches. */
734 if (host != NULL) {
735 if ((s = match_maybe_hashed(host, lineinfo.hosts,
736 &hashed)) == -1) {
737 debug2("%s: %s:%ld: bad host hash \"%.32s\"",
738 __func__, path, linenum, lineinfo.hosts);
739 goto bad;
740 }
741 if (s == 1) {
742 lineinfo.status = HKF_STATUS_MATCHED;
743 lineinfo.match |= HKF_MATCH_HOST |
744 (hashed ? HKF_MATCH_HOST_HASHED : 0);
745 }
746 /* Try matching IP address if supplied */
747 if (ip != NULL) {
748 if ((s = match_maybe_hashed(ip, lineinfo.hosts,
749 &hashed)) == -1) {
750 debug2("%s: %s:%ld: bad ip hash "
751 "\"%.32s\"", __func__, path,
752 linenum, lineinfo.hosts);
753 goto bad;
754 }
755 if (s == 1) {
756 lineinfo.status = HKF_STATUS_MATCHED;
757 lineinfo.match |= HKF_MATCH_IP |
758 (hashed ? HKF_MATCH_IP_HASHED : 0);
759 }
760 }
761 /*
762 * Skip this line if host matching requested and
763 * neither host nor address matched.
764 */
765 if ((options & HKF_WANT_MATCH) != 0 &&
766 lineinfo.status != HKF_STATUS_MATCHED)
767 continue;
768 }
769
770 /* Got a match. Skip host name and any following whitespace */
771 for (; *cp2 == ' ' || *cp2 == '\t'; cp2++)
772 ;
773 if (*cp2 == '\0' || *cp2 == '#') {
774 debug2("%s:%ld: truncated before key type",
775 path, linenum);
776 goto bad;
777 }
778 lineinfo.rawkey = cp = cp2;
779
780 if ((options & HKF_WANT_PARSE_KEY) != 0) {
781 /*
782 * Extract the key from the line. This will skip
783 * any leading whitespace. Ignore badly formatted
784 * lines.
785 */
786 if ((lineinfo.key = sshkey_new(KEY_UNSPEC)) == NULL) {
787 error("%s: sshkey_new failed", __func__);
788 r = SSH_ERR_ALLOC_FAIL;
789 break;
790 }
791 if (!hostfile_read_key(&cp, &kbits, lineinfo.key)) {
792 #ifdef WITH_SSH1
793 sshkey_free(lineinfo.key);
794 lineinfo.key = sshkey_new(KEY_RSA1);
795 if (lineinfo.key == NULL) {
796 error("%s: sshkey_new fail", __func__);
797 r = SSH_ERR_ALLOC_FAIL;
798 break;
799 }
800 if (!hostfile_read_key(&cp, &kbits,
801 lineinfo.key))
802 goto bad;
803 #else
804 goto bad;
805 #endif
806 }
807 lineinfo.keytype = lineinfo.key->type;
808 lineinfo.comment = cp;
809 } else {
810 /* Extract and parse key type */
811 l = strcspn(lineinfo.rawkey, " \t");
812 if (l <= 1 || l >= sizeof(ktype) ||
813 lineinfo.rawkey[l] == '\0')
814 goto bad;
815 memcpy(ktype, lineinfo.rawkey, l);
816 ktype[l] = '\0';
817 lineinfo.keytype = sshkey_type_from_name(ktype);
818
819 /*
820 * Assume RSA1 if the first component is a short
821 * decimal number.
822 */
823 if (lineinfo.keytype == KEY_UNSPEC && l < 8 &&
824 strspn(ktype, "0123456789") == l)
825 lineinfo.keytype = KEY_RSA1;
826
827 /*
828 * Check that something other than whitespace follows
829 * the key type. This won't catch all corruption, but
830 * it does catch trivial truncation.
831 */
832 cp2 += l; /* Skip past key type */
833 for (; *cp2 == ' ' || *cp2 == '\t'; cp2++)
834 ;
835 if (*cp2 == '\0' || *cp2 == '#') {
836 debug2("%s:%ld: truncated after key type",
837 path, linenum);
838 lineinfo.keytype = KEY_UNSPEC;
839 }
840 if (lineinfo.keytype == KEY_UNSPEC) {
841 bad:
842 sshkey_free(lineinfo.key);
843 lineinfo.key = NULL;
844 lineinfo.status = HKF_STATUS_INVALID;
845 if ((r = callback(&lineinfo, ctx)) != 0)
846 break;
847 continue;
848 }
849 }
850 if ((r = callback(&lineinfo, ctx)) != 0)
851 break;
852 }
853 sshkey_free(lineinfo.key);
854 fclose(f);
855 return r;
856 }
857