Annotation of src/usr.bin/ssh/hostfile.c, Revision 1.82
1.82 ! djm 1: /* $OpenBSD: hostfile.c,v 1.81 2020/06/26 05:02:03 dtucker Exp $ */
1.1 deraadt 2: /*
1.8 deraadt 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.
1.16 markus 7: *
1.20 deraadt 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: *
1.28 markus 15: * Copyright (c) 1999, 2000 Markus Friedl. All rights reserved.
1.20 deraadt 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.
1.8 deraadt 37: */
1.1 deraadt 38:
1.41 stevesk 39: #include <sys/types.h>
1.62 djm 40: #include <sys/stat.h>
1.41 stevesk 41:
42: #include <netinet/in.h>
1.33 djm 43:
1.60 djm 44: #include <errno.h>
1.33 djm 45: #include <resolv.h>
1.44 stevesk 46: #include <stdio.h>
1.43 stevesk 47: #include <stdlib.h>
1.42 stevesk 48: #include <string.h>
1.57 djm 49: #include <stdarg.h>
1.62 djm 50: #include <unistd.h>
1.1 deraadt 51:
1.45 deraadt 52: #include "xmalloc.h"
1.14 markus 53: #include "match.h"
1.59 djm 54: #include "sshkey.h"
1.14 markus 55: #include "hostfile.h"
1.24 markus 56: #include "log.h"
1.49 djm 57: #include "misc.h"
1.81 dtucker 58: #include "pathnames.h"
1.59 djm 59: #include "ssherr.h"
1.53 djm 60: #include "digest.h"
1.54 markus 61: #include "hmac.h"
1.49 djm 62:
63: struct hostkeys {
64: struct hostkey_entry *entries;
65: u_int num_entries;
66: };
1.33 djm 67:
1.60 djm 68: /* XXX hmac is too easy to dictionary attack; use bcrypt? */
69:
1.33 djm 70: static int
1.52 djm 71: extract_salt(const char *s, u_int l, u_char *salt, size_t salt_len)
1.33 djm 72: {
73: char *p, *b64salt;
74: u_int b64len;
75: int ret;
76:
77: if (l < sizeof(HASH_MAGIC) - 1) {
78: debug2("extract_salt: string too short");
79: return (-1);
80: }
81: if (strncmp(s, HASH_MAGIC, sizeof(HASH_MAGIC) - 1) != 0) {
82: debug2("extract_salt: invalid magic identifier");
83: return (-1);
84: }
85: s += sizeof(HASH_MAGIC) - 1;
86: l -= sizeof(HASH_MAGIC) - 1;
87: if ((p = memchr(s, HASH_DELIM, l)) == NULL) {
88: debug2("extract_salt: missing salt termination character");
89: return (-1);
90: }
91:
92: b64len = p - s;
93: /* Sanity check */
94: if (b64len == 0 || b64len > 1024) {
95: debug2("extract_salt: bad encoded salt length %u", b64len);
96: return (-1);
97: }
98: b64salt = xmalloc(1 + b64len);
99: memcpy(b64salt, s, b64len);
100: b64salt[b64len] = '\0';
101:
102: ret = __b64_pton(b64salt, salt, salt_len);
1.51 djm 103: free(b64salt);
1.33 djm 104: if (ret == -1) {
105: debug2("extract_salt: salt decode error");
106: return (-1);
107: }
1.54 markus 108: if (ret != (int)ssh_hmac_bytes(SSH_DIGEST_SHA1)) {
109: debug2("extract_salt: expected salt len %zd, got %d",
110: ssh_hmac_bytes(SSH_DIGEST_SHA1), ret);
1.33 djm 111: return (-1);
112: }
1.34 deraadt 113:
1.33 djm 114: return (0);
115: }
116:
117: char *
118: host_hash(const char *host, const char *name_from_hostfile, u_int src_len)
119: {
1.54 markus 120: struct ssh_hmac_ctx *ctx;
1.52 djm 121: u_char salt[256], result[256];
122: char uu_salt[512], uu_result[512];
1.33 djm 123: static char encoded[1024];
1.67 tedu 124: u_int len;
1.33 djm 125:
1.54 markus 126: len = ssh_digest_bytes(SSH_DIGEST_SHA1);
1.33 djm 127:
128: if (name_from_hostfile == NULL) {
129: /* Create new salt */
1.67 tedu 130: arc4random_buf(salt, len);
1.33 djm 131: } else {
132: /* Extract salt from known host entry */
133: if (extract_salt(name_from_hostfile, src_len, salt,
134: sizeof(salt)) == -1)
135: return (NULL);
136: }
137:
1.54 markus 138: if ((ctx = ssh_hmac_start(SSH_DIGEST_SHA1)) == NULL ||
139: ssh_hmac_init(ctx, salt, len) < 0 ||
140: ssh_hmac_update(ctx, host, strlen(host)) < 0 ||
141: ssh_hmac_final(ctx, result, sizeof(result)))
142: fatal("%s: ssh_hmac failed", __func__);
143: ssh_hmac_free(ctx);
1.33 djm 144:
1.34 deraadt 145: if (__b64_ntop(salt, len, uu_salt, sizeof(uu_salt)) == -1 ||
1.33 djm 146: __b64_ntop(result, len, uu_result, sizeof(uu_result)) == -1)
1.54 markus 147: fatal("%s: __b64_ntop failed", __func__);
1.33 djm 148:
149: snprintf(encoded, sizeof(encoded), "%s%s%c%s", HASH_MAGIC, uu_salt,
150: HASH_DELIM, uu_result);
151:
152: return (encoded);
153: }
1.1 deraadt 154:
1.9 markus 155: /*
1.14 markus 156: * Parses an RSA (number of bits, e, n) or DSA key from a string. Moves the
157: * pointer over the key. Skips any whitespace at the beginning and at end.
1.9 markus 158: */
1.1 deraadt 159:
1.29 jakob 160: int
1.59 djm 161: hostfile_read_key(char **cpp, u_int *bitsp, struct sshkey *ret)
1.1 deraadt 162: {
1.7 markus 163: char *cp;
164:
165: /* Skip leading whitespace. */
1.9 markus 166: for (cp = *cpp; *cp == ' ' || *cp == '\t'; cp++)
167: ;
1.1 deraadt 168:
1.76 dtucker 169: if (sshkey_read(ret, &cp) != 0)
1.7 markus 170: return 0;
171:
172: /* Skip trailing whitespace. */
1.9 markus 173: for (; *cp == ' ' || *cp == '\t'; cp++)
174: ;
1.7 markus 175:
176: /* Return results. */
177: *cpp = cp;
1.59 djm 178: if (bitsp != NULL)
179: *bitsp = sshkey_size(ret);
1.7 markus 180: return 1;
1.14 markus 181: }
1.1 deraadt 182:
1.49 djm 183: static HostkeyMarker
1.48 djm 184: check_markers(char **cpp)
185: {
186: char marker[32], *sp, *cp = *cpp;
187: int ret = MRK_NONE;
188:
189: while (*cp == '@') {
190: /* Only one marker is allowed */
191: if (ret != MRK_NONE)
192: return MRK_ERROR;
193: /* Markers are terminated by whitespace */
194: if ((sp = strchr(cp, ' ')) == NULL &&
195: (sp = strchr(cp, '\t')) == NULL)
196: return MRK_ERROR;
197: /* Extract marker for comparison */
198: if (sp <= cp + 1 || sp >= cp + sizeof(marker))
199: return MRK_ERROR;
200: memcpy(marker, cp, sp - cp);
201: marker[sp - cp] = '\0';
202: if (strcmp(marker, CA_MARKER) == 0)
203: ret = MRK_CA;
204: else if (strcmp(marker, REVOKE_MARKER) == 0)
205: ret = MRK_REVOKE;
206: else
207: return MRK_ERROR;
208:
209: /* Skip past marker and any whitespace that follows it */
210: cp = sp;
211: for (; *cp == ' ' || *cp == '\t'; cp++)
212: ;
213: }
214: *cpp = cp;
215: return ret;
216: }
217:
1.49 djm 218: struct hostkeys *
219: init_hostkeys(void)
220: {
221: struct hostkeys *ret = xcalloc(1, sizeof(*ret));
222:
223: ret->entries = NULL;
224: return ret;
225: }
1.1 deraadt 226:
1.61 djm 227: struct load_callback_ctx {
228: const char *host;
229: u_long num_loaded;
230: struct hostkeys *hostkeys;
231: };
232:
233: static int
234: record_hostkey(struct hostkey_foreach_line *l, void *_ctx)
1.1 deraadt 235: {
1.61 djm 236: struct load_callback_ctx *ctx = (struct load_callback_ctx *)_ctx;
237: struct hostkeys *hostkeys = ctx->hostkeys;
238: struct hostkey_entry *tmp;
239:
240: if (l->status == HKF_STATUS_INVALID) {
1.65 djm 241: /* XXX make this verbose() in the future */
242: debug("%s:%ld: parse error in hostkeys file",
1.61 djm 243: l->path, l->linenum);
244: return 0;
245: }
1.7 markus 246:
1.61 djm 247: debug3("%s: found %skey type %s in file %s:%lu", __func__,
248: l->marker == MRK_NONE ? "" :
249: (l->marker == MRK_CA ? "ca " : "revoked "),
250: sshkey_type(l->key), l->path, l->linenum);
1.71 deraadt 251: if ((tmp = recallocarray(hostkeys->entries, hostkeys->num_entries,
1.61 djm 252: hostkeys->num_entries + 1, sizeof(*hostkeys->entries))) == NULL)
253: return SSH_ERR_ALLOC_FAIL;
254: hostkeys->entries = tmp;
255: hostkeys->entries[hostkeys->num_entries].host = xstrdup(ctx->host);
256: hostkeys->entries[hostkeys->num_entries].file = xstrdup(l->path);
257: hostkeys->entries[hostkeys->num_entries].line = l->linenum;
258: hostkeys->entries[hostkeys->num_entries].key = l->key;
259: l->key = NULL; /* steal it */
260: hostkeys->entries[hostkeys->num_entries].marker = l->marker;
261: hostkeys->num_entries++;
262: ctx->num_loaded++;
1.7 markus 263:
1.61 djm 264: return 0;
265: }
1.47 djm 266:
1.61 djm 267: void
268: load_hostkeys(struct hostkeys *hostkeys, const char *host, const char *path)
269: {
270: int r;
271: struct load_callback_ctx ctx;
1.7 markus 272:
1.61 djm 273: ctx.host = host;
274: ctx.num_loaded = 0;
275: ctx.hostkeys = hostkeys;
276:
1.64 djm 277: if ((r = hostkeys_foreach(path, record_hostkey, &ctx, host, NULL,
278: HKF_WANT_MATCH|HKF_WANT_PARSE_KEY)) != 0) {
1.61 djm 279: if (r != SSH_ERR_SYSTEM_ERROR && errno != ENOENT)
280: debug("%s: hostkeys_foreach failed for %s: %s",
281: __func__, path, ssh_err(r));
282: }
283: if (ctx.num_loaded != 0)
284: debug3("%s: loaded %lu keys from %s", __func__,
285: ctx.num_loaded, host);
1.58 djm 286: }
1.49 djm 287:
288: void
289: free_hostkeys(struct hostkeys *hostkeys)
290: {
291: u_int i;
292:
293: for (i = 0; i < hostkeys->num_entries; i++) {
1.51 djm 294: free(hostkeys->entries[i].host);
295: free(hostkeys->entries[i].file);
1.59 djm 296: sshkey_free(hostkeys->entries[i].key);
1.55 tedu 297: explicit_bzero(hostkeys->entries + i, sizeof(*hostkeys->entries));
1.49 djm 298: }
1.51 djm 299: free(hostkeys->entries);
1.78 jsg 300: freezero(hostkeys, sizeof(*hostkeys));
1.49 djm 301: }
302:
303: static int
1.59 djm 304: check_key_not_revoked(struct hostkeys *hostkeys, struct sshkey *k)
1.49 djm 305: {
1.59 djm 306: int is_cert = sshkey_is_cert(k);
1.49 djm 307: u_int i;
1.7 markus 308:
1.49 djm 309: for (i = 0; i < hostkeys->num_entries; i++) {
310: if (hostkeys->entries[i].marker != MRK_REVOKE)
1.30 markus 311: continue;
1.59 djm 312: if (sshkey_equal_public(k, hostkeys->entries[i].key))
1.49 djm 313: return -1;
1.79 markus 314: if (is_cert && k != NULL &&
1.59 djm 315: sshkey_equal_public(k->cert->signature_key,
1.49 djm 316: hostkeys->entries[i].key))
317: return -1;
318: }
319: return 0;
320: }
321:
322: /*
323: * Match keys against a specified key, or look one up by key type.
324: *
325: * If looking for a keytype (key == NULL) and one is found then return
326: * HOST_FOUND, otherwise HOST_NEW.
327: *
328: * If looking for a key (key != NULL):
329: * 1. If the key is a cert and a matching CA is found, return HOST_OK
330: * 2. If the key is not a cert and a matching key is found, return HOST_OK
331: * 3. If no key matches but a key with a different type is found, then
332: * return HOST_CHANGED
333: * 4. If no matching keys are found, then return HOST_NEW.
334: *
335: * Finally, check any found key is not revoked.
336: */
337: static HostStatus
338: check_hostkeys_by_key_or_type(struct hostkeys *hostkeys,
1.59 djm 339: struct sshkey *k, int keytype, const struct hostkey_entry **found)
1.49 djm 340: {
341: u_int i;
342: HostStatus end_return = HOST_NEW;
1.59 djm 343: int want_cert = sshkey_is_cert(k);
1.49 djm 344: HostkeyMarker want_marker = want_cert ? MRK_CA : MRK_NONE;
345:
346: if (found != NULL)
347: *found = NULL;
1.30 markus 348:
1.49 djm 349: for (i = 0; i < hostkeys->num_entries; i++) {
350: if (hostkeys->entries[i].marker != want_marker)
351: continue;
352: if (k == NULL) {
353: if (hostkeys->entries[i].key->type != keytype)
354: continue;
355: end_return = HOST_FOUND;
356: if (found != NULL)
357: *found = hostkeys->entries + i;
358: k = hostkeys->entries[i].key;
359: break;
360: }
361: if (want_cert) {
1.59 djm 362: if (sshkey_equal_public(k->cert->signature_key,
1.49 djm 363: hostkeys->entries[i].key)) {
364: /* A matching CA exists */
365: end_return = HOST_OK;
366: if (found != NULL)
367: *found = hostkeys->entries + i;
368: break;
1.48 djm 369: }
1.49 djm 370: } else {
1.59 djm 371: if (sshkey_equal(k, hostkeys->entries[i].key)) {
1.49 djm 372: end_return = HOST_OK;
373: if (found != NULL)
374: *found = hostkeys->entries + i;
375: break;
1.48 djm 376: }
1.49 djm 377: /* A non-maching key exists */
378: end_return = HOST_CHANGED;
379: if (found != NULL)
380: *found = hostkeys->entries + i;
1.48 djm 381: }
1.1 deraadt 382: }
1.49 djm 383: if (check_key_not_revoked(hostkeys, k) != 0) {
384: end_return = HOST_REVOKED;
385: if (found != NULL)
386: *found = NULL;
387: }
1.7 markus 388: return end_return;
1.30 markus 389: }
1.58 djm 390:
1.30 markus 391: HostStatus
1.59 djm 392: check_key_in_hostkeys(struct hostkeys *hostkeys, struct sshkey *key,
1.49 djm 393: const struct hostkey_entry **found)
1.30 markus 394: {
395: if (key == NULL)
396: fatal("no key to look up");
1.49 djm 397: return check_hostkeys_by_key_or_type(hostkeys, key, 0, found);
1.30 markus 398: }
399:
400: int
1.49 djm 401: lookup_key_in_hostkeys_by_type(struct hostkeys *hostkeys, int keytype,
402: const struct hostkey_entry **found)
1.30 markus 403: {
1.49 djm 404: return (check_hostkeys_by_key_or_type(hostkeys, NULL, keytype,
405: found) == HOST_FOUND);
1.80 djm 406: }
407:
408: int
409: lookup_marker_in_hostkeys(struct hostkeys *hostkeys, int want_marker)
410: {
411: u_int i;
412:
413: for (i = 0; i < hostkeys->num_entries; i++) {
414: if (hostkeys->entries[i].marker == (HostkeyMarker)want_marker)
415: return 1;
416: }
417: return 0;
1.1 deraadt 418: }
419:
1.62 djm 420: static int
1.64 djm 421: write_host_entry(FILE *f, const char *host, const char *ip,
1.62 djm 422: const struct sshkey *key, int store_hash)
423: {
424: int r, success = 0;
1.68 djm 425: char *hashed_host = NULL, *lhost;
426:
427: lhost = xstrdup(host);
428: lowercase(lhost);
1.62 djm 429:
430: if (store_hash) {
1.68 djm 431: if ((hashed_host = host_hash(lhost, NULL, 0)) == NULL) {
1.62 djm 432: error("%s: host_hash failed", __func__);
1.68 djm 433: free(lhost);
1.62 djm 434: return 0;
435: }
1.64 djm 436: fprintf(f, "%s ", hashed_host);
437: } else if (ip != NULL)
1.68 djm 438: fprintf(f, "%s,%s ", lhost, ip);
439: else {
440: fprintf(f, "%s ", lhost);
441: }
442: free(lhost);
1.62 djm 443: if ((r = sshkey_write(key, f)) == 0)
444: success = 1;
445: else
446: error("%s: sshkey_write failed: %s", __func__, ssh_err(r));
447: fputc('\n', f);
448: return success;
449: }
450:
1.9 markus 451: /*
1.81 dtucker 452: * Create user ~/.ssh directory if it doesn't exist and we want to write to it.
453: * If notify is set, a message will be emitted if the directory is created.
454: */
455: void
456: hostfile_create_user_ssh_dir(const char *filename, int notify)
457: {
458: char *dotsshdir = NULL, *p;
459: size_t len;
460: struct stat st;
461:
462: if ((p = strrchr(filename, '/')) == NULL)
463: return;
464: len = p - filename;
465: dotsshdir = tilde_expand_filename("~/" _PATH_SSH_USER_DIR, getuid());
1.82 ! djm 466: if (strlen(dotsshdir) > len || strncmp(filename, dotsshdir, len) != 0)
! 467: goto out; /* not ~/.ssh prefixed */
! 468: if (stat(dotsshdir, &st) == 0)
! 469: goto out; /* dir already exists */
1.81 dtucker 470: else if (errno != ENOENT)
471: error("Could not stat %s: %s", dotsshdir, strerror(errno));
1.82 ! djm 472: else {
! 473: if (mkdir(dotsshdir, 0700) == -1)
! 474: error("Could not create directory '%.200s' (%s).",
! 475: dotsshdir, strerror(errno));
! 476: else if (notify)
! 477: logit("Created directory '%s'.", dotsshdir);
! 478: }
! 479: out:
1.81 dtucker 480: free(dotsshdir);
481: }
1.82 ! djm 482:
1.81 dtucker 483:
484: /*
1.9 markus 485: * Appends an entry to the host file. Returns false if the entry could not
486: * be appended.
487: */
1.2 provos 488: int
1.59 djm 489: add_host_to_hostfile(const char *filename, const char *host,
490: const struct sshkey *key, int store_hash)
1.1 deraadt 491: {
1.7 markus 492: FILE *f;
1.62 djm 493: int success;
1.33 djm 494:
1.14 markus 495: if (key == NULL)
1.17 markus 496: return 1; /* XXX ? */
1.81 dtucker 497: hostfile_create_user_ssh_dir(filename, 0);
1.7 markus 498: f = fopen(filename, "a");
499: if (!f)
500: return 0;
1.64 djm 501: success = write_host_entry(f, host, NULL, key, store_hash);
1.62 djm 502: fclose(f);
503: return success;
504: }
505:
506: struct host_delete_ctx {
507: FILE *out;
508: int quiet;
509: const char *host;
1.64 djm 510: int *skip_keys; /* XXX split for host/ip? might want to ensure both */
1.62 djm 511: struct sshkey * const *keys;
512: size_t nkeys;
1.64 djm 513: int modified;
1.62 djm 514: };
515:
516: static int
517: host_delete(struct hostkey_foreach_line *l, void *_ctx)
518: {
519: struct host_delete_ctx *ctx = (struct host_delete_ctx *)_ctx;
1.64 djm 520: int loglevel = ctx->quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE;
1.62 djm 521: size_t i;
522:
1.64 djm 523: if (l->status == HKF_STATUS_MATCHED) {
1.62 djm 524: if (l->marker != MRK_NONE) {
525: /* Don't remove CA and revocation lines */
526: fprintf(ctx->out, "%s\n", l->line);
527: return 0;
528: }
1.33 djm 529:
1.62 djm 530: /*
531: * If this line contains one of the keys that we will be
532: * adding later, then don't change it and mark the key for
533: * skipping.
534: */
535: for (i = 0; i < ctx->nkeys; i++) {
536: if (sshkey_equal(ctx->keys[i], l->key)) {
537: ctx->skip_keys[i] = 1;
538: fprintf(ctx->out, "%s\n", l->line);
539: debug3("%s: %s key already at %s:%ld", __func__,
540: sshkey_type(l->key), l->path, l->linenum);
541: return 0;
542: }
543: }
544:
545: /*
546: * Hostname matches and has no CA/revoke marker, delete it
547: * by *not* writing the line to ctx->out.
548: */
1.64 djm 549: do_log2(loglevel, "%s%s%s:%ld: Removed %s key for host %s",
1.62 djm 550: ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "",
1.64 djm 551: l->path, l->linenum, sshkey_type(l->key), ctx->host);
552: ctx->modified = 1;
1.62 djm 553: return 0;
554: }
555: /* Retain non-matching hosts and invalid lines when deleting */
556: if (l->status == HKF_STATUS_INVALID) {
557: do_log2(loglevel, "%s%s%s:%ld: invalid known_hosts entry",
558: ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "",
559: l->path, l->linenum);
560: }
561: fprintf(ctx->out, "%s\n", l->line);
562: return 0;
563: }
564:
565: int
1.64 djm 566: hostfile_replace_entries(const char *filename, const char *host, const char *ip,
567: struct sshkey **keys, size_t nkeys, int store_hash, int quiet, int hash_alg)
1.62 djm 568: {
569: int r, fd, oerrno = 0;
1.64 djm 570: int loglevel = quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE;
1.62 djm 571: struct host_delete_ctx ctx;
1.64 djm 572: char *fp, *temp = NULL, *back = NULL;
1.62 djm 573: mode_t omask;
574: size_t i;
575:
1.63 djm 576: omask = umask(077);
577:
1.62 djm 578: memset(&ctx, 0, sizeof(ctx));
579: ctx.host = host;
580: ctx.quiet = quiet;
581: if ((ctx.skip_keys = calloc(nkeys, sizeof(*ctx.skip_keys))) == NULL)
582: return SSH_ERR_ALLOC_FAIL;
583: ctx.keys = keys;
584: ctx.nkeys = nkeys;
1.64 djm 585: ctx.modified = 0;
1.62 djm 586:
587: /*
588: * Prepare temporary file for in-place deletion.
589: */
1.75 deraadt 590: if ((r = asprintf(&temp, "%s.XXXXXXXXXXX", filename)) == -1 ||
1.74 deraadt 591: (r = asprintf(&back, "%s.old", filename)) == -1) {
1.62 djm 592: r = SSH_ERR_ALLOC_FAIL;
593: goto fail;
594: }
595:
596: if ((fd = mkstemp(temp)) == -1) {
597: oerrno = errno;
598: error("%s: mkstemp: %s", __func__, strerror(oerrno));
599: r = SSH_ERR_SYSTEM_ERROR;
600: goto fail;
601: }
602: if ((ctx.out = fdopen(fd, "w")) == NULL) {
603: oerrno = errno;
604: close(fd);
605: error("%s: fdopen: %s", __func__, strerror(oerrno));
606: r = SSH_ERR_SYSTEM_ERROR;
607: goto fail;
608: }
609:
610: /* Remove all entries for the specified host from the file */
1.64 djm 611: if ((r = hostkeys_foreach(filename, host_delete, &ctx, host, ip,
1.62 djm 612: HKF_WANT_PARSE_KEY)) != 0) {
1.77 djm 613: oerrno = errno;
1.62 djm 614: error("%s: hostkeys_foreach failed: %s", __func__, ssh_err(r));
615: goto fail;
616: }
617:
618: /* Add the requested keys */
619: for (i = 0; i < nkeys; i++) {
620: if (ctx.skip_keys[i])
621: continue;
1.64 djm 622: if ((fp = sshkey_fingerprint(keys[i], hash_alg,
623: SSH_FP_DEFAULT)) == NULL) {
624: r = SSH_ERR_ALLOC_FAIL;
625: goto fail;
626: }
627: do_log2(loglevel, "%s%sAdding new key for %s to %s: %s %s",
628: quiet ? __func__ : "", quiet ? ": " : "", host, filename,
629: sshkey_ssh_name(keys[i]), fp);
630: free(fp);
631: if (!write_host_entry(ctx.out, host, ip, keys[i], store_hash)) {
1.62 djm 632: r = SSH_ERR_INTERNAL_ERROR;
633: goto fail;
634: }
1.64 djm 635: ctx.modified = 1;
1.33 djm 636: }
1.62 djm 637: fclose(ctx.out);
638: ctx.out = NULL;
1.33 djm 639:
1.64 djm 640: if (ctx.modified) {
641: /* Backup the original file and replace it with the temporary */
642: if (unlink(back) == -1 && errno != ENOENT) {
643: oerrno = errno;
644: error("%s: unlink %.100s: %s", __func__,
645: back, strerror(errno));
646: r = SSH_ERR_SYSTEM_ERROR;
647: goto fail;
648: }
649: if (link(filename, back) == -1) {
650: oerrno = errno;
651: error("%s: link %.100s to %.100s: %s", __func__,
652: filename, back, strerror(errno));
653: r = SSH_ERR_SYSTEM_ERROR;
654: goto fail;
655: }
656: if (rename(temp, filename) == -1) {
657: oerrno = errno;
658: error("%s: rename \"%s\" to \"%s\": %s", __func__,
659: temp, filename, strerror(errno));
660: r = SSH_ERR_SYSTEM_ERROR;
661: goto fail;
662: }
663: } else {
664: /* No changes made; just delete the temporary file */
665: if (unlink(temp) != 0)
666: error("%s: unlink \"%s\": %s", __func__,
667: temp, strerror(errno));
1.62 djm 668: }
1.64 djm 669:
1.62 djm 670: /* success */
671: r = 0;
672: fail:
673: if (temp != NULL && r != 0)
674: unlink(temp);
675: free(temp);
676: free(back);
677: if (ctx.out != NULL)
678: fclose(ctx.out);
679: free(ctx.skip_keys);
1.63 djm 680: umask(omask);
1.62 djm 681: if (r == SSH_ERR_SYSTEM_ERROR)
682: errno = oerrno;
683: return r;
1.60 djm 684: }
685:
686: static int
687: match_maybe_hashed(const char *host, const char *names, int *was_hashed)
688: {
689: int hashed = *names == HASH_DELIM;
690: const char *hashed_host;
691: size_t nlen = strlen(names);
692:
693: if (was_hashed != NULL)
694: *was_hashed = hashed;
695: if (hashed) {
696: if ((hashed_host = host_hash(host, names, nlen)) == NULL)
697: return -1;
698: return nlen == strlen(hashed_host) &&
699: strncmp(hashed_host, names, nlen) == 0;
700: }
1.66 djm 701: return match_hostname(host, names) == 1;
1.60 djm 702: }
703:
704: int
705: hostkeys_foreach(const char *path, hostkeys_foreach_fn *callback, void *ctx,
1.64 djm 706: const char *host, const char *ip, u_int options)
1.60 djm 707: {
708: FILE *f;
1.72 markus 709: char *line = NULL, ktype[128];
1.60 djm 710: u_long linenum = 0;
711: char *cp, *cp2;
712: u_int kbits;
1.64 djm 713: int hashed;
1.60 djm 714: int s, r = 0;
715: struct hostkey_foreach_line lineinfo;
1.72 markus 716: size_t linesize = 0, l;
1.60 djm 717:
718: memset(&lineinfo, 0, sizeof(lineinfo));
1.64 djm 719: if (host == NULL && (options & HKF_WANT_MATCH) != 0)
1.60 djm 720: return SSH_ERR_INVALID_ARGUMENT;
721: if ((f = fopen(path, "r")) == NULL)
722: return SSH_ERR_SYSTEM_ERROR;
723:
724: debug3("%s: reading file \"%s\"", __func__, path);
1.72 markus 725: while (getline(&line, &linesize, f) != -1) {
726: linenum++;
1.60 djm 727: line[strcspn(line, "\n")] = '\0';
728:
1.73 djm 729: free(lineinfo.line);
1.60 djm 730: sshkey_free(lineinfo.key);
731: memset(&lineinfo, 0, sizeof(lineinfo));
732: lineinfo.path = path;
733: lineinfo.linenum = linenum;
1.72 markus 734: lineinfo.line = xstrdup(line);
1.64 djm 735: lineinfo.marker = MRK_NONE;
1.60 djm 736: lineinfo.status = HKF_STATUS_OK;
1.64 djm 737: lineinfo.keytype = KEY_UNSPEC;
1.60 djm 738:
739: /* Skip any leading whitespace, comments and empty lines. */
740: for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
741: ;
742: if (!*cp || *cp == '#' || *cp == '\n') {
1.64 djm 743: if ((options & HKF_WANT_MATCH) == 0) {
1.60 djm 744: lineinfo.status = HKF_STATUS_COMMENT;
745: if ((r = callback(&lineinfo, ctx)) != 0)
746: break;
747: }
748: continue;
749: }
750:
751: if ((lineinfo.marker = check_markers(&cp)) == MRK_ERROR) {
752: verbose("%s: invalid marker at %s:%lu",
753: __func__, path, linenum);
1.64 djm 754: if ((options & HKF_WANT_MATCH) == 0)
1.60 djm 755: goto bad;
756: continue;
757: }
758:
759: /* Find the end of the host name portion. */
760: for (cp2 = cp; *cp2 && *cp2 != ' ' && *cp2 != '\t'; cp2++)
761: ;
762: lineinfo.hosts = cp;
763: *cp2++ = '\0';
764:
765: /* Check if the host name matches. */
766: if (host != NULL) {
1.64 djm 767: if ((s = match_maybe_hashed(host, lineinfo.hosts,
768: &hashed)) == -1) {
1.60 djm 769: debug2("%s: %s:%ld: bad host hash \"%.32s\"",
770: __func__, path, linenum, lineinfo.hosts);
771: goto bad;
772: }
1.64 djm 773: if (s == 1) {
774: lineinfo.status = HKF_STATUS_MATCHED;
775: lineinfo.match |= HKF_MATCH_HOST |
776: (hashed ? HKF_MATCH_HOST_HASHED : 0);
777: }
778: /* Try matching IP address if supplied */
779: if (ip != NULL) {
780: if ((s = match_maybe_hashed(ip, lineinfo.hosts,
781: &hashed)) == -1) {
782: debug2("%s: %s:%ld: bad ip hash "
783: "\"%.32s\"", __func__, path,
784: linenum, lineinfo.hosts);
785: goto bad;
786: }
787: if (s == 1) {
788: lineinfo.status = HKF_STATUS_MATCHED;
789: lineinfo.match |= HKF_MATCH_IP |
790: (hashed ? HKF_MATCH_IP_HASHED : 0);
791: }
792: }
793: /*
794: * Skip this line if host matching requested and
795: * neither host nor address matched.
796: */
797: if ((options & HKF_WANT_MATCH) != 0 &&
798: lineinfo.status != HKF_STATUS_MATCHED)
799: continue;
1.60 djm 800: }
801:
802: /* Got a match. Skip host name and any following whitespace */
803: for (; *cp2 == ' ' || *cp2 == '\t'; cp2++)
804: ;
805: if (*cp2 == '\0' || *cp2 == '#') {
1.64 djm 806: debug2("%s:%ld: truncated before key type",
807: path, linenum);
1.60 djm 808: goto bad;
809: }
810: lineinfo.rawkey = cp = cp2;
811:
812: if ((options & HKF_WANT_PARSE_KEY) != 0) {
813: /*
814: * Extract the key from the line. This will skip
815: * any leading whitespace. Ignore badly formatted
816: * lines.
817: */
818: if ((lineinfo.key = sshkey_new(KEY_UNSPEC)) == NULL) {
819: error("%s: sshkey_new failed", __func__);
1.64 djm 820: r = SSH_ERR_ALLOC_FAIL;
821: break;
1.60 djm 822: }
823: if (!hostfile_read_key(&cp, &kbits, lineinfo.key)) {
824: goto bad;
825: }
1.64 djm 826: lineinfo.keytype = lineinfo.key->type;
827: lineinfo.comment = cp;
828: } else {
829: /* Extract and parse key type */
830: l = strcspn(lineinfo.rawkey, " \t");
831: if (l <= 1 || l >= sizeof(ktype) ||
832: lineinfo.rawkey[l] == '\0')
833: goto bad;
834: memcpy(ktype, lineinfo.rawkey, l);
835: ktype[l] = '\0';
836: lineinfo.keytype = sshkey_type_from_name(ktype);
1.65 djm 837:
1.64 djm 838: /*
1.70 djm 839: * Assume legacy RSA1 if the first component is a short
1.64 djm 840: * decimal number.
841: */
842: if (lineinfo.keytype == KEY_UNSPEC && l < 8 &&
843: strspn(ktype, "0123456789") == l)
1.70 djm 844: goto bad;
1.65 djm 845:
1.64 djm 846: /*
847: * Check that something other than whitespace follows
848: * the key type. This won't catch all corruption, but
849: * it does catch trivial truncation.
850: */
851: cp2 += l; /* Skip past key type */
852: for (; *cp2 == ' ' || *cp2 == '\t'; cp2++)
853: ;
854: if (*cp2 == '\0' || *cp2 == '#') {
855: debug2("%s:%ld: truncated after key type",
856: path, linenum);
857: lineinfo.keytype = KEY_UNSPEC;
858: }
859: if (lineinfo.keytype == KEY_UNSPEC) {
1.60 djm 860: bad:
1.64 djm 861: sshkey_free(lineinfo.key);
862: lineinfo.key = NULL;
1.60 djm 863: lineinfo.status = HKF_STATUS_INVALID;
864: if ((r = callback(&lineinfo, ctx)) != 0)
865: break;
866: continue;
867: }
868: }
869: if ((r = callback(&lineinfo, ctx)) != 0)
870: break;
871: }
872: sshkey_free(lineinfo.key);
1.72 markus 873: free(lineinfo.line);
874: free(line);
1.60 djm 875: fclose(f);
876: return r;
1.1 deraadt 877: }
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