Annotation of src/usr.bin/ssh/hostfile.c, Revision 1.88
1.88 ! djm 1: /* $OpenBSD: hostfile.c,v 1.87 2020/12/20 23:36:51 djm 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"
1.88 ! djm 62: #include "sshbuf.h"
1.49 djm 63:
64: struct hostkeys {
65: struct hostkey_entry *entries;
66: u_int num_entries;
67: };
1.33 djm 68:
1.60 djm 69: /* XXX hmac is too easy to dictionary attack; use bcrypt? */
70:
1.33 djm 71: static int
1.52 djm 72: extract_salt(const char *s, u_int l, u_char *salt, size_t salt_len)
1.33 djm 73: {
74: char *p, *b64salt;
75: u_int b64len;
76: int ret;
77:
78: if (l < sizeof(HASH_MAGIC) - 1) {
79: debug2("extract_salt: string too short");
80: return (-1);
81: }
82: if (strncmp(s, HASH_MAGIC, sizeof(HASH_MAGIC) - 1) != 0) {
83: debug2("extract_salt: invalid magic identifier");
84: return (-1);
85: }
86: s += sizeof(HASH_MAGIC) - 1;
87: l -= sizeof(HASH_MAGIC) - 1;
88: if ((p = memchr(s, HASH_DELIM, l)) == NULL) {
89: debug2("extract_salt: missing salt termination character");
90: return (-1);
91: }
92:
93: b64len = p - s;
94: /* Sanity check */
95: if (b64len == 0 || b64len > 1024) {
96: debug2("extract_salt: bad encoded salt length %u", b64len);
97: return (-1);
98: }
99: b64salt = xmalloc(1 + b64len);
100: memcpy(b64salt, s, b64len);
101: b64salt[b64len] = '\0';
102:
103: ret = __b64_pton(b64salt, salt, salt_len);
1.51 djm 104: free(b64salt);
1.33 djm 105: if (ret == -1) {
106: debug2("extract_salt: salt decode error");
107: return (-1);
108: }
1.54 markus 109: if (ret != (int)ssh_hmac_bytes(SSH_DIGEST_SHA1)) {
110: debug2("extract_salt: expected salt len %zd, got %d",
111: ssh_hmac_bytes(SSH_DIGEST_SHA1), ret);
1.33 djm 112: return (-1);
113: }
1.34 deraadt 114:
1.33 djm 115: return (0);
116: }
117:
118: char *
119: host_hash(const char *host, const char *name_from_hostfile, u_int src_len)
120: {
1.54 markus 121: struct ssh_hmac_ctx *ctx;
1.52 djm 122: u_char salt[256], result[256];
123: char uu_salt[512], uu_result[512];
1.33 djm 124: static char encoded[1024];
1.67 tedu 125: u_int len;
1.33 djm 126:
1.54 markus 127: len = ssh_digest_bytes(SSH_DIGEST_SHA1);
1.33 djm 128:
129: if (name_from_hostfile == NULL) {
130: /* Create new salt */
1.67 tedu 131: arc4random_buf(salt, len);
1.33 djm 132: } else {
133: /* Extract salt from known host entry */
134: if (extract_salt(name_from_hostfile, src_len, salt,
135: sizeof(salt)) == -1)
136: return (NULL);
137: }
138:
1.54 markus 139: if ((ctx = ssh_hmac_start(SSH_DIGEST_SHA1)) == NULL ||
140: ssh_hmac_init(ctx, salt, len) < 0 ||
141: ssh_hmac_update(ctx, host, strlen(host)) < 0 ||
142: ssh_hmac_final(ctx, result, sizeof(result)))
1.86 djm 143: fatal_f("ssh_hmac failed");
1.54 markus 144: ssh_hmac_free(ctx);
1.33 djm 145:
1.34 deraadt 146: if (__b64_ntop(salt, len, uu_salt, sizeof(uu_salt)) == -1 ||
1.33 djm 147: __b64_ntop(result, len, uu_result, sizeof(uu_result)) == -1)
1.86 djm 148: fatal_f("__b64_ntop failed");
1.33 djm 149:
150: snprintf(encoded, sizeof(encoded), "%s%s%c%s", HASH_MAGIC, uu_salt,
151: HASH_DELIM, uu_result);
152:
153: return (encoded);
154: }
1.1 deraadt 155:
1.9 markus 156: /*
1.14 markus 157: * Parses an RSA (number of bits, e, n) or DSA key from a string. Moves the
158: * pointer over the key. Skips any whitespace at the beginning and at end.
1.9 markus 159: */
1.1 deraadt 160:
1.29 jakob 161: int
1.59 djm 162: hostfile_read_key(char **cpp, u_int *bitsp, struct sshkey *ret)
1.1 deraadt 163: {
1.7 markus 164: char *cp;
165:
166: /* Skip leading whitespace. */
1.9 markus 167: for (cp = *cpp; *cp == ' ' || *cp == '\t'; cp++)
168: ;
1.1 deraadt 169:
1.76 dtucker 170: if (sshkey_read(ret, &cp) != 0)
1.7 markus 171: return 0;
172:
173: /* Skip trailing whitespace. */
1.9 markus 174: for (; *cp == ' ' || *cp == '\t'; cp++)
175: ;
1.7 markus 176:
177: /* Return results. */
178: *cpp = cp;
1.59 djm 179: if (bitsp != NULL)
180: *bitsp = sshkey_size(ret);
1.7 markus 181: return 1;
1.14 markus 182: }
1.1 deraadt 183:
1.49 djm 184: static HostkeyMarker
1.48 djm 185: check_markers(char **cpp)
186: {
187: char marker[32], *sp, *cp = *cpp;
188: int ret = MRK_NONE;
189:
190: while (*cp == '@') {
191: /* Only one marker is allowed */
192: if (ret != MRK_NONE)
193: return MRK_ERROR;
194: /* Markers are terminated by whitespace */
195: if ((sp = strchr(cp, ' ')) == NULL &&
196: (sp = strchr(cp, '\t')) == NULL)
197: return MRK_ERROR;
198: /* Extract marker for comparison */
199: if (sp <= cp + 1 || sp >= cp + sizeof(marker))
200: return MRK_ERROR;
201: memcpy(marker, cp, sp - cp);
202: marker[sp - cp] = '\0';
203: if (strcmp(marker, CA_MARKER) == 0)
204: ret = MRK_CA;
205: else if (strcmp(marker, REVOKE_MARKER) == 0)
206: ret = MRK_REVOKE;
207: else
208: return MRK_ERROR;
209:
210: /* Skip past marker and any whitespace that follows it */
211: cp = sp;
212: for (; *cp == ' ' || *cp == '\t'; cp++)
213: ;
214: }
215: *cpp = cp;
216: return ret;
217: }
218:
1.49 djm 219: struct hostkeys *
220: init_hostkeys(void)
221: {
222: struct hostkeys *ret = xcalloc(1, sizeof(*ret));
223:
224: ret->entries = NULL;
225: return ret;
226: }
1.1 deraadt 227:
1.61 djm 228: struct load_callback_ctx {
229: const char *host;
230: u_long num_loaded;
231: struct hostkeys *hostkeys;
232: };
233:
234: static int
235: record_hostkey(struct hostkey_foreach_line *l, void *_ctx)
1.1 deraadt 236: {
1.61 djm 237: struct load_callback_ctx *ctx = (struct load_callback_ctx *)_ctx;
238: struct hostkeys *hostkeys = ctx->hostkeys;
239: struct hostkey_entry *tmp;
240:
241: if (l->status == HKF_STATUS_INVALID) {
1.65 djm 242: /* XXX make this verbose() in the future */
243: debug("%s:%ld: parse error in hostkeys file",
1.61 djm 244: l->path, l->linenum);
245: return 0;
246: }
1.7 markus 247:
1.86 djm 248: debug3_f("found %skey type %s in file %s:%lu",
1.61 djm 249: l->marker == MRK_NONE ? "" :
250: (l->marker == MRK_CA ? "ca " : "revoked "),
251: sshkey_type(l->key), l->path, l->linenum);
1.71 deraadt 252: if ((tmp = recallocarray(hostkeys->entries, hostkeys->num_entries,
1.61 djm 253: hostkeys->num_entries + 1, sizeof(*hostkeys->entries))) == NULL)
254: return SSH_ERR_ALLOC_FAIL;
255: hostkeys->entries = tmp;
256: hostkeys->entries[hostkeys->num_entries].host = xstrdup(ctx->host);
257: hostkeys->entries[hostkeys->num_entries].file = xstrdup(l->path);
258: hostkeys->entries[hostkeys->num_entries].line = l->linenum;
259: hostkeys->entries[hostkeys->num_entries].key = l->key;
260: l->key = NULL; /* steal it */
261: hostkeys->entries[hostkeys->num_entries].marker = l->marker;
1.87 djm 262: hostkeys->entries[hostkeys->num_entries].note = l->note;
1.61 djm 263: hostkeys->num_entries++;
264: ctx->num_loaded++;
1.7 markus 265:
1.61 djm 266: return 0;
267: }
1.47 djm 268:
1.61 djm 269: void
1.87 djm 270: load_hostkeys_file(struct hostkeys *hostkeys, const char *host,
271: const char *path, FILE *f, u_int note)
1.61 djm 272: {
273: int r;
274: struct load_callback_ctx ctx;
1.7 markus 275:
1.61 djm 276: ctx.host = host;
277: ctx.num_loaded = 0;
278: ctx.hostkeys = hostkeys;
279:
1.87 djm 280: if ((r = hostkeys_foreach_file(path, f, record_hostkey, &ctx, host,
281: NULL, HKF_WANT_MATCH|HKF_WANT_PARSE_KEY, note)) != 0) {
1.61 djm 282: if (r != SSH_ERR_SYSTEM_ERROR && errno != ENOENT)
1.86 djm 283: debug_fr(r, "hostkeys_foreach failed for %s", path);
1.61 djm 284: }
285: if (ctx.num_loaded != 0)
1.86 djm 286: debug3_f("loaded %lu keys from %s", ctx.num_loaded, host);
1.58 djm 287: }
1.49 djm 288:
289: void
1.87 djm 290: load_hostkeys(struct hostkeys *hostkeys, const char *host, const char *path,
291: u_int note)
292: {
293: FILE *f;
294:
295: if ((f = fopen(path, "r")) == NULL) {
296: debug_f("fopen %s: %s", path, strerror(errno));
297: return;
298: }
299:
300: load_hostkeys_file(hostkeys, host, path, f, note);
301: fclose(f);
302: }
303:
304: void
1.49 djm 305: free_hostkeys(struct hostkeys *hostkeys)
306: {
307: u_int i;
308:
309: for (i = 0; i < hostkeys->num_entries; i++) {
1.51 djm 310: free(hostkeys->entries[i].host);
311: free(hostkeys->entries[i].file);
1.59 djm 312: sshkey_free(hostkeys->entries[i].key);
1.55 tedu 313: explicit_bzero(hostkeys->entries + i, sizeof(*hostkeys->entries));
1.49 djm 314: }
1.51 djm 315: free(hostkeys->entries);
1.78 jsg 316: freezero(hostkeys, sizeof(*hostkeys));
1.49 djm 317: }
318:
319: static int
1.59 djm 320: check_key_not_revoked(struct hostkeys *hostkeys, struct sshkey *k)
1.49 djm 321: {
1.59 djm 322: int is_cert = sshkey_is_cert(k);
1.49 djm 323: u_int i;
1.7 markus 324:
1.49 djm 325: for (i = 0; i < hostkeys->num_entries; i++) {
326: if (hostkeys->entries[i].marker != MRK_REVOKE)
1.30 markus 327: continue;
1.59 djm 328: if (sshkey_equal_public(k, hostkeys->entries[i].key))
1.49 djm 329: return -1;
1.79 markus 330: if (is_cert && k != NULL &&
1.59 djm 331: sshkey_equal_public(k->cert->signature_key,
1.49 djm 332: hostkeys->entries[i].key))
333: return -1;
334: }
335: return 0;
336: }
337:
338: /*
339: * Match keys against a specified key, or look one up by key type.
340: *
341: * If looking for a keytype (key == NULL) and one is found then return
342: * HOST_FOUND, otherwise HOST_NEW.
343: *
344: * If looking for a key (key != NULL):
345: * 1. If the key is a cert and a matching CA is found, return HOST_OK
346: * 2. If the key is not a cert and a matching key is found, return HOST_OK
347: * 3. If no key matches but a key with a different type is found, then
348: * return HOST_CHANGED
349: * 4. If no matching keys are found, then return HOST_NEW.
350: *
351: * Finally, check any found key is not revoked.
352: */
353: static HostStatus
354: check_hostkeys_by_key_or_type(struct hostkeys *hostkeys,
1.83 djm 355: struct sshkey *k, int keytype, int nid, const struct hostkey_entry **found)
1.49 djm 356: {
357: u_int i;
358: HostStatus end_return = HOST_NEW;
1.59 djm 359: int want_cert = sshkey_is_cert(k);
1.49 djm 360: HostkeyMarker want_marker = want_cert ? MRK_CA : MRK_NONE;
361:
362: if (found != NULL)
363: *found = NULL;
1.30 markus 364:
1.49 djm 365: for (i = 0; i < hostkeys->num_entries; i++) {
366: if (hostkeys->entries[i].marker != want_marker)
367: continue;
368: if (k == NULL) {
369: if (hostkeys->entries[i].key->type != keytype)
370: continue;
1.83 djm 371: if (nid != -1 &&
372: sshkey_type_plain(keytype) == KEY_ECDSA &&
373: hostkeys->entries[i].key->ecdsa_nid != nid)
374: continue;
1.49 djm 375: end_return = HOST_FOUND;
376: if (found != NULL)
377: *found = hostkeys->entries + i;
378: k = hostkeys->entries[i].key;
379: break;
380: }
381: if (want_cert) {
1.59 djm 382: if (sshkey_equal_public(k->cert->signature_key,
1.49 djm 383: hostkeys->entries[i].key)) {
384: /* A matching CA exists */
385: end_return = HOST_OK;
386: if (found != NULL)
387: *found = hostkeys->entries + i;
388: break;
1.48 djm 389: }
1.49 djm 390: } else {
1.59 djm 391: if (sshkey_equal(k, hostkeys->entries[i].key)) {
1.49 djm 392: end_return = HOST_OK;
393: if (found != NULL)
394: *found = hostkeys->entries + i;
395: break;
1.48 djm 396: }
1.49 djm 397: /* A non-maching key exists */
398: end_return = HOST_CHANGED;
399: if (found != NULL)
400: *found = hostkeys->entries + i;
1.48 djm 401: }
1.1 deraadt 402: }
1.49 djm 403: if (check_key_not_revoked(hostkeys, k) != 0) {
404: end_return = HOST_REVOKED;
405: if (found != NULL)
406: *found = NULL;
407: }
1.7 markus 408: return end_return;
1.30 markus 409: }
1.58 djm 410:
1.30 markus 411: HostStatus
1.59 djm 412: check_key_in_hostkeys(struct hostkeys *hostkeys, struct sshkey *key,
1.49 djm 413: const struct hostkey_entry **found)
1.30 markus 414: {
415: if (key == NULL)
416: fatal("no key to look up");
1.83 djm 417: return check_hostkeys_by_key_or_type(hostkeys, key, 0, -1, found);
1.30 markus 418: }
419:
420: int
1.83 djm 421: lookup_key_in_hostkeys_by_type(struct hostkeys *hostkeys, int keytype, int nid,
1.49 djm 422: const struct hostkey_entry **found)
1.30 markus 423: {
1.83 djm 424: return (check_hostkeys_by_key_or_type(hostkeys, NULL, keytype, nid,
1.49 djm 425: found) == HOST_FOUND);
1.80 djm 426: }
427:
428: int
429: lookup_marker_in_hostkeys(struct hostkeys *hostkeys, int want_marker)
430: {
431: u_int i;
432:
433: for (i = 0; i < hostkeys->num_entries; i++) {
434: if (hostkeys->entries[i].marker == (HostkeyMarker)want_marker)
435: return 1;
436: }
437: return 0;
1.1 deraadt 438: }
439:
1.62 djm 440: static int
1.64 djm 441: write_host_entry(FILE *f, const char *host, const char *ip,
1.62 djm 442: const struct sshkey *key, int store_hash)
443: {
444: int r, success = 0;
1.68 djm 445: char *hashed_host = NULL, *lhost;
446:
447: lhost = xstrdup(host);
448: lowercase(lhost);
1.62 djm 449:
450: if (store_hash) {
1.68 djm 451: if ((hashed_host = host_hash(lhost, NULL, 0)) == NULL) {
1.86 djm 452: error_f("host_hash failed");
1.68 djm 453: free(lhost);
1.62 djm 454: return 0;
455: }
1.64 djm 456: fprintf(f, "%s ", hashed_host);
457: } else if (ip != NULL)
1.68 djm 458: fprintf(f, "%s,%s ", lhost, ip);
459: else {
460: fprintf(f, "%s ", lhost);
461: }
462: free(lhost);
1.62 djm 463: if ((r = sshkey_write(key, f)) == 0)
464: success = 1;
465: else
1.86 djm 466: error_fr(r, "sshkey_write");
1.62 djm 467: fputc('\n', f);
1.84 djm 468: /* If hashing is enabled, the IP address needs to go on its own line */
469: if (success && store_hash && ip != NULL)
470: success = write_host_entry(f, ip, NULL, key, 1);
1.62 djm 471: return success;
472: }
473:
1.9 markus 474: /*
1.81 dtucker 475: * Create user ~/.ssh directory if it doesn't exist and we want to write to it.
476: * If notify is set, a message will be emitted if the directory is created.
477: */
478: void
479: hostfile_create_user_ssh_dir(const char *filename, int notify)
480: {
481: char *dotsshdir = NULL, *p;
482: size_t len;
483: struct stat st;
484:
485: if ((p = strrchr(filename, '/')) == NULL)
486: return;
487: len = p - filename;
488: dotsshdir = tilde_expand_filename("~/" _PATH_SSH_USER_DIR, getuid());
1.82 djm 489: if (strlen(dotsshdir) > len || strncmp(filename, dotsshdir, len) != 0)
490: goto out; /* not ~/.ssh prefixed */
491: if (stat(dotsshdir, &st) == 0)
492: goto out; /* dir already exists */
1.81 dtucker 493: else if (errno != ENOENT)
494: error("Could not stat %s: %s", dotsshdir, strerror(errno));
1.82 djm 495: else {
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: }
502: out:
1.81 dtucker 503: free(dotsshdir);
504: }
1.82 djm 505:
1.81 dtucker 506:
507: /*
1.9 markus 508: * Appends an entry to the host file. Returns false if the entry could not
509: * be appended.
510: */
1.2 provos 511: int
1.59 djm 512: add_host_to_hostfile(const char *filename, const char *host,
513: const struct sshkey *key, int store_hash)
1.1 deraadt 514: {
1.7 markus 515: FILE *f;
1.62 djm 516: int success;
1.33 djm 517:
1.14 markus 518: if (key == NULL)
1.17 markus 519: return 1; /* XXX ? */
1.81 dtucker 520: hostfile_create_user_ssh_dir(filename, 0);
1.7 markus 521: f = fopen(filename, "a");
522: if (!f)
523: return 0;
1.64 djm 524: success = write_host_entry(f, host, NULL, key, store_hash);
1.62 djm 525: fclose(f);
526: return success;
527: }
528:
529: struct host_delete_ctx {
530: FILE *out;
531: int quiet;
1.85 djm 532: const char *host, *ip;
533: u_int *match_keys; /* mask of HKF_MATCH_* for this key */
1.62 djm 534: struct sshkey * const *keys;
535: size_t nkeys;
1.64 djm 536: int modified;
1.62 djm 537: };
538:
539: static int
540: host_delete(struct hostkey_foreach_line *l, void *_ctx)
541: {
542: struct host_delete_ctx *ctx = (struct host_delete_ctx *)_ctx;
1.64 djm 543: int loglevel = ctx->quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE;
1.62 djm 544: size_t i;
545:
1.85 djm 546: /* Don't remove CA and revocation lines */
547: if (l->status == HKF_STATUS_MATCHED && l->marker == MRK_NONE) {
1.62 djm 548: /*
549: * If this line contains one of the keys that we will be
550: * adding later, then don't change it and mark the key for
551: * skipping.
552: */
553: for (i = 0; i < ctx->nkeys; i++) {
1.85 djm 554: if (!sshkey_equal(ctx->keys[i], l->key))
555: continue;
556: ctx->match_keys[i] |= l->match;
557: fprintf(ctx->out, "%s\n", l->line);
1.86 djm 558: debug3_f("%s key already at %s:%ld",
1.85 djm 559: sshkey_type(l->key), l->path, l->linenum);
560: return 0;
1.62 djm 561: }
562:
563: /*
564: * Hostname matches and has no CA/revoke marker, delete it
565: * by *not* writing the line to ctx->out.
566: */
1.64 djm 567: do_log2(loglevel, "%s%s%s:%ld: Removed %s key for host %s",
1.62 djm 568: ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "",
1.64 djm 569: l->path, l->linenum, sshkey_type(l->key), ctx->host);
570: ctx->modified = 1;
1.62 djm 571: return 0;
572: }
573: /* Retain non-matching hosts and invalid lines when deleting */
574: if (l->status == HKF_STATUS_INVALID) {
575: do_log2(loglevel, "%s%s%s:%ld: invalid known_hosts entry",
576: ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "",
577: l->path, l->linenum);
578: }
579: fprintf(ctx->out, "%s\n", l->line);
580: return 0;
581: }
582:
583: int
1.64 djm 584: hostfile_replace_entries(const char *filename, const char *host, const char *ip,
585: struct sshkey **keys, size_t nkeys, int store_hash, int quiet, int hash_alg)
1.62 djm 586: {
587: int r, fd, oerrno = 0;
1.64 djm 588: int loglevel = quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE;
1.62 djm 589: struct host_delete_ctx ctx;
1.64 djm 590: char *fp, *temp = NULL, *back = NULL;
1.85 djm 591: const char *what;
1.62 djm 592: mode_t omask;
593: size_t i;
1.85 djm 594: u_int want;
1.62 djm 595:
1.63 djm 596: omask = umask(077);
597:
1.62 djm 598: memset(&ctx, 0, sizeof(ctx));
599: ctx.host = host;
1.85 djm 600: ctx.ip = ip;
1.62 djm 601: ctx.quiet = quiet;
1.85 djm 602:
603: if ((ctx.match_keys = calloc(nkeys, sizeof(*ctx.match_keys))) == NULL)
1.62 djm 604: return SSH_ERR_ALLOC_FAIL;
605: ctx.keys = keys;
606: ctx.nkeys = nkeys;
1.64 djm 607: ctx.modified = 0;
1.62 djm 608:
609: /*
610: * Prepare temporary file for in-place deletion.
611: */
1.75 deraadt 612: if ((r = asprintf(&temp, "%s.XXXXXXXXXXX", filename)) == -1 ||
1.74 deraadt 613: (r = asprintf(&back, "%s.old", filename)) == -1) {
1.62 djm 614: r = SSH_ERR_ALLOC_FAIL;
615: goto fail;
616: }
617:
618: if ((fd = mkstemp(temp)) == -1) {
619: oerrno = errno;
1.86 djm 620: error_f("mkstemp: %s", strerror(oerrno));
1.62 djm 621: r = SSH_ERR_SYSTEM_ERROR;
622: goto fail;
623: }
624: if ((ctx.out = fdopen(fd, "w")) == NULL) {
625: oerrno = errno;
626: close(fd);
1.86 djm 627: error_f("fdopen: %s", strerror(oerrno));
1.62 djm 628: r = SSH_ERR_SYSTEM_ERROR;
629: goto fail;
630: }
631:
1.85 djm 632: /* Remove stale/mismatching entries for the specified host */
1.64 djm 633: if ((r = hostkeys_foreach(filename, host_delete, &ctx, host, ip,
1.87 djm 634: HKF_WANT_PARSE_KEY, 0)) != 0) {
1.77 djm 635: oerrno = errno;
1.86 djm 636: error_fr(r, "hostkeys_foreach");
1.62 djm 637: goto fail;
638: }
639:
1.85 djm 640: /* Re-add the requested keys */
641: want = HKF_MATCH_HOST | (ip == NULL ? 0 : HKF_MATCH_IP);
1.62 djm 642: for (i = 0; i < nkeys; i++) {
1.85 djm 643: if ((want & ctx.match_keys[i]) == want)
1.62 djm 644: continue;
1.64 djm 645: if ((fp = sshkey_fingerprint(keys[i], hash_alg,
646: SSH_FP_DEFAULT)) == NULL) {
647: r = SSH_ERR_ALLOC_FAIL;
648: goto fail;
649: }
1.85 djm 650: /* write host/ip */
651: what = "";
652: if (ctx.match_keys[i] == 0) {
653: what = "Adding new key";
654: if (!write_host_entry(ctx.out, host, ip,
655: keys[i], store_hash)) {
656: r = SSH_ERR_INTERNAL_ERROR;
657: goto fail;
658: }
659: } else if ((want & ~ctx.match_keys[i]) == HKF_MATCH_HOST) {
660: what = "Fixing match (hostname)";
661: if (!write_host_entry(ctx.out, host, NULL,
662: keys[i], store_hash)) {
663: r = SSH_ERR_INTERNAL_ERROR;
664: goto fail;
665: }
666: } else if ((want & ~ctx.match_keys[i]) == HKF_MATCH_IP) {
667: what = "Fixing match (address)";
668: if (!write_host_entry(ctx.out, ip, NULL,
669: keys[i], store_hash)) {
670: r = SSH_ERR_INTERNAL_ERROR;
671: goto fail;
672: }
673: }
674: do_log2(loglevel, "%s%s%s for %s%s%s to %s: %s %s",
675: quiet ? __func__ : "", quiet ? ": " : "", what,
676: host, ip == NULL ? "" : ",", ip == NULL ? "" : ip, filename,
1.64 djm 677: sshkey_ssh_name(keys[i]), fp);
678: free(fp);
679: ctx.modified = 1;
1.33 djm 680: }
1.62 djm 681: fclose(ctx.out);
682: ctx.out = NULL;
1.33 djm 683:
1.64 djm 684: if (ctx.modified) {
685: /* Backup the original file and replace it with the temporary */
686: if (unlink(back) == -1 && errno != ENOENT) {
687: oerrno = errno;
1.86 djm 688: error_f("unlink %.100s: %s", back, strerror(errno));
1.64 djm 689: r = SSH_ERR_SYSTEM_ERROR;
690: goto fail;
691: }
692: if (link(filename, back) == -1) {
693: oerrno = errno;
1.86 djm 694: error_f("link %.100s to %.100s: %s", filename,
695: back, strerror(errno));
1.64 djm 696: r = SSH_ERR_SYSTEM_ERROR;
697: goto fail;
698: }
699: if (rename(temp, filename) == -1) {
700: oerrno = errno;
1.86 djm 701: error_f("rename \"%s\" to \"%s\": %s", temp,
702: filename, strerror(errno));
1.64 djm 703: r = SSH_ERR_SYSTEM_ERROR;
704: goto fail;
705: }
706: } else {
707: /* No changes made; just delete the temporary file */
708: if (unlink(temp) != 0)
1.86 djm 709: error_f("unlink \"%s\": %s", temp, strerror(errno));
1.62 djm 710: }
1.64 djm 711:
1.62 djm 712: /* success */
713: r = 0;
714: fail:
715: if (temp != NULL && r != 0)
716: unlink(temp);
717: free(temp);
718: free(back);
719: if (ctx.out != NULL)
720: fclose(ctx.out);
1.85 djm 721: free(ctx.match_keys);
1.63 djm 722: umask(omask);
1.62 djm 723: if (r == SSH_ERR_SYSTEM_ERROR)
724: errno = oerrno;
725: return r;
1.60 djm 726: }
727:
728: static int
729: match_maybe_hashed(const char *host, const char *names, int *was_hashed)
730: {
731: int hashed = *names == HASH_DELIM;
732: const char *hashed_host;
733: size_t nlen = strlen(names);
734:
735: if (was_hashed != NULL)
736: *was_hashed = hashed;
737: if (hashed) {
738: if ((hashed_host = host_hash(host, names, nlen)) == NULL)
739: return -1;
740: return nlen == strlen(hashed_host) &&
741: strncmp(hashed_host, names, nlen) == 0;
742: }
1.66 djm 743: return match_hostname(host, names) == 1;
1.60 djm 744: }
745:
746: int
1.87 djm 747: hostkeys_foreach_file(const char *path, FILE *f, hostkeys_foreach_fn *callback,
748: void *ctx, const char *host, const char *ip, u_int options, u_int note)
1.60 djm 749: {
1.72 markus 750: char *line = NULL, ktype[128];
1.60 djm 751: u_long linenum = 0;
752: char *cp, *cp2;
753: u_int kbits;
1.64 djm 754: int hashed;
1.60 djm 755: int s, r = 0;
756: struct hostkey_foreach_line lineinfo;
1.72 markus 757: size_t linesize = 0, l;
1.60 djm 758:
759: memset(&lineinfo, 0, sizeof(lineinfo));
1.64 djm 760: if (host == NULL && (options & HKF_WANT_MATCH) != 0)
1.60 djm 761: return SSH_ERR_INVALID_ARGUMENT;
762:
1.72 markus 763: while (getline(&line, &linesize, f) != -1) {
764: linenum++;
1.60 djm 765: line[strcspn(line, "\n")] = '\0';
766:
1.73 djm 767: free(lineinfo.line);
1.60 djm 768: sshkey_free(lineinfo.key);
769: memset(&lineinfo, 0, sizeof(lineinfo));
770: lineinfo.path = path;
771: lineinfo.linenum = linenum;
1.72 markus 772: lineinfo.line = xstrdup(line);
1.64 djm 773: lineinfo.marker = MRK_NONE;
1.60 djm 774: lineinfo.status = HKF_STATUS_OK;
1.64 djm 775: lineinfo.keytype = KEY_UNSPEC;
1.87 djm 776: lineinfo.note = note;
1.60 djm 777:
778: /* Skip any leading whitespace, comments and empty lines. */
779: for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
780: ;
781: if (!*cp || *cp == '#' || *cp == '\n') {
1.64 djm 782: if ((options & HKF_WANT_MATCH) == 0) {
1.60 djm 783: lineinfo.status = HKF_STATUS_COMMENT;
784: if ((r = callback(&lineinfo, ctx)) != 0)
785: break;
786: }
787: continue;
788: }
789:
790: if ((lineinfo.marker = check_markers(&cp)) == MRK_ERROR) {
1.86 djm 791: verbose_f("invalid marker at %s:%lu", path, linenum);
1.64 djm 792: if ((options & HKF_WANT_MATCH) == 0)
1.60 djm 793: goto bad;
794: continue;
795: }
796:
797: /* Find the end of the host name portion. */
798: for (cp2 = cp; *cp2 && *cp2 != ' ' && *cp2 != '\t'; cp2++)
799: ;
800: lineinfo.hosts = cp;
801: *cp2++ = '\0';
802:
803: /* Check if the host name matches. */
804: if (host != NULL) {
1.64 djm 805: if ((s = match_maybe_hashed(host, lineinfo.hosts,
806: &hashed)) == -1) {
1.86 djm 807: debug2_f("%s:%ld: bad host hash \"%.32s\"",
808: path, linenum, lineinfo.hosts);
1.60 djm 809: goto bad;
810: }
1.64 djm 811: if (s == 1) {
812: lineinfo.status = HKF_STATUS_MATCHED;
813: lineinfo.match |= HKF_MATCH_HOST |
814: (hashed ? HKF_MATCH_HOST_HASHED : 0);
815: }
816: /* Try matching IP address if supplied */
817: if (ip != NULL) {
818: if ((s = match_maybe_hashed(ip, lineinfo.hosts,
819: &hashed)) == -1) {
1.86 djm 820: debug2_f("%s:%ld: bad ip hash "
821: "\"%.32s\"", path, linenum,
822: lineinfo.hosts);
1.64 djm 823: goto bad;
824: }
825: if (s == 1) {
826: lineinfo.status = HKF_STATUS_MATCHED;
827: lineinfo.match |= HKF_MATCH_IP |
828: (hashed ? HKF_MATCH_IP_HASHED : 0);
829: }
830: }
831: /*
832: * Skip this line if host matching requested and
833: * neither host nor address matched.
834: */
835: if ((options & HKF_WANT_MATCH) != 0 &&
836: lineinfo.status != HKF_STATUS_MATCHED)
837: continue;
1.60 djm 838: }
839:
840: /* Got a match. Skip host name and any following whitespace */
841: for (; *cp2 == ' ' || *cp2 == '\t'; cp2++)
842: ;
843: if (*cp2 == '\0' || *cp2 == '#') {
1.64 djm 844: debug2("%s:%ld: truncated before key type",
845: path, linenum);
1.60 djm 846: goto bad;
847: }
848: lineinfo.rawkey = cp = cp2;
849:
850: if ((options & HKF_WANT_PARSE_KEY) != 0) {
851: /*
852: * Extract the key from the line. This will skip
853: * any leading whitespace. Ignore badly formatted
854: * lines.
855: */
856: if ((lineinfo.key = sshkey_new(KEY_UNSPEC)) == NULL) {
1.86 djm 857: error_f("sshkey_new failed");
1.64 djm 858: r = SSH_ERR_ALLOC_FAIL;
859: break;
1.60 djm 860: }
861: if (!hostfile_read_key(&cp, &kbits, lineinfo.key)) {
862: goto bad;
863: }
1.64 djm 864: lineinfo.keytype = lineinfo.key->type;
865: lineinfo.comment = cp;
866: } else {
867: /* Extract and parse key type */
868: l = strcspn(lineinfo.rawkey, " \t");
869: if (l <= 1 || l >= sizeof(ktype) ||
870: lineinfo.rawkey[l] == '\0')
871: goto bad;
872: memcpy(ktype, lineinfo.rawkey, l);
873: ktype[l] = '\0';
874: lineinfo.keytype = sshkey_type_from_name(ktype);
1.65 djm 875:
1.64 djm 876: /*
1.70 djm 877: * Assume legacy RSA1 if the first component is a short
1.64 djm 878: * decimal number.
879: */
880: if (lineinfo.keytype == KEY_UNSPEC && l < 8 &&
881: strspn(ktype, "0123456789") == l)
1.70 djm 882: goto bad;
1.65 djm 883:
1.64 djm 884: /*
885: * Check that something other than whitespace follows
886: * the key type. This won't catch all corruption, but
887: * it does catch trivial truncation.
888: */
889: cp2 += l; /* Skip past key type */
890: for (; *cp2 == ' ' || *cp2 == '\t'; cp2++)
891: ;
892: if (*cp2 == '\0' || *cp2 == '#') {
893: debug2("%s:%ld: truncated after key type",
894: path, linenum);
895: lineinfo.keytype = KEY_UNSPEC;
896: }
897: if (lineinfo.keytype == KEY_UNSPEC) {
1.60 djm 898: bad:
1.64 djm 899: sshkey_free(lineinfo.key);
900: lineinfo.key = NULL;
1.60 djm 901: lineinfo.status = HKF_STATUS_INVALID;
902: if ((r = callback(&lineinfo, ctx)) != 0)
903: break;
904: continue;
905: }
906: }
907: if ((r = callback(&lineinfo, ctx)) != 0)
908: break;
909: }
910: sshkey_free(lineinfo.key);
1.72 markus 911: free(lineinfo.line);
912: free(line);
1.87 djm 913: return r;
914: }
915:
916: int
917: hostkeys_foreach(const char *path, hostkeys_foreach_fn *callback, void *ctx,
918: const char *host, const char *ip, u_int options, u_int note)
919: {
920: FILE *f;
921: int r, oerrno;
922:
923: if ((f = fopen(path, "r")) == NULL)
924: return SSH_ERR_SYSTEM_ERROR;
925:
926: debug3_f("reading file \"%s\"", path);
927: r = hostkeys_foreach_file(path, f, callback, ctx, host, ip,
928: options, note);
929: oerrno = errno;
1.60 djm 930: fclose(f);
1.87 djm 931: errno = oerrno;
1.60 djm 932: return r;
1.1 deraadt 933: }
![[BACK]](/icons/back.gif){kind=icon}
Return to hostfile.c CVS log ![[TXT]](/icons/text.gif){kind=icon}
![[DIR]](/icons/dir.gif){kind=icon}
Up to [local] / src / usr.bin / ssh