Annotation of src/usr.bin/ssh/hostfile.c, Revision 1.87
1.87 ! djm 1: /* $OpenBSD: hostfile.c,v 1.86 2020/10/18 11:32:01 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"
1.49 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)))
1.86 djm 142: fatal_f("ssh_hmac failed");
1.54 markus 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)
1.86 djm 147: fatal_f("__b64_ntop failed");
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:
1.86 djm 247: debug3_f("found %skey type %s in file %s:%lu",
1.61 djm 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;
1.87 ! djm 261: hostkeys->entries[hostkeys->num_entries].note = l->note;
1.61 djm 262: hostkeys->num_entries++;
263: ctx->num_loaded++;
1.7 markus 264:
1.61 djm 265: return 0;
266: }
1.47 djm 267:
1.61 djm 268: void
1.87 ! djm 269: load_hostkeys_file(struct hostkeys *hostkeys, const char *host,
! 270: const char *path, FILE *f, u_int note)
1.61 djm 271: {
272: int r;
273: struct load_callback_ctx ctx;
1.7 markus 274:
1.61 djm 275: ctx.host = host;
276: ctx.num_loaded = 0;
277: ctx.hostkeys = hostkeys;
278:
1.87 ! djm 279: if ((r = hostkeys_foreach_file(path, f, record_hostkey, &ctx, host,
! 280: NULL, HKF_WANT_MATCH|HKF_WANT_PARSE_KEY, note)) != 0) {
1.61 djm 281: if (r != SSH_ERR_SYSTEM_ERROR && errno != ENOENT)
1.86 djm 282: debug_fr(r, "hostkeys_foreach failed for %s", path);
1.61 djm 283: }
284: if (ctx.num_loaded != 0)
1.86 djm 285: debug3_f("loaded %lu keys from %s", ctx.num_loaded, host);
1.58 djm 286: }
1.49 djm 287:
288: void
1.87 ! djm 289: load_hostkeys(struct hostkeys *hostkeys, const char *host, const char *path,
! 290: u_int note)
! 291: {
! 292: FILE *f;
! 293:
! 294: if ((f = fopen(path, "r")) == NULL) {
! 295: debug_f("fopen %s: %s", path, strerror(errno));
! 296: return;
! 297: }
! 298:
! 299: load_hostkeys_file(hostkeys, host, path, f, note);
! 300: fclose(f);
! 301: }
! 302:
! 303: void
1.49 djm 304: free_hostkeys(struct hostkeys *hostkeys)
305: {
306: u_int i;
307:
308: for (i = 0; i < hostkeys->num_entries; i++) {
1.51 djm 309: free(hostkeys->entries[i].host);
310: free(hostkeys->entries[i].file);
1.59 djm 311: sshkey_free(hostkeys->entries[i].key);
1.55 tedu 312: explicit_bzero(hostkeys->entries + i, sizeof(*hostkeys->entries));
1.49 djm 313: }
1.51 djm 314: free(hostkeys->entries);
1.78 jsg 315: freezero(hostkeys, sizeof(*hostkeys));
1.49 djm 316: }
317:
318: static int
1.59 djm 319: check_key_not_revoked(struct hostkeys *hostkeys, struct sshkey *k)
1.49 djm 320: {
1.59 djm 321: int is_cert = sshkey_is_cert(k);
1.49 djm 322: u_int i;
1.7 markus 323:
1.49 djm 324: for (i = 0; i < hostkeys->num_entries; i++) {
325: if (hostkeys->entries[i].marker != MRK_REVOKE)
1.30 markus 326: continue;
1.59 djm 327: if (sshkey_equal_public(k, hostkeys->entries[i].key))
1.49 djm 328: return -1;
1.79 markus 329: if (is_cert && k != NULL &&
1.59 djm 330: sshkey_equal_public(k->cert->signature_key,
1.49 djm 331: hostkeys->entries[i].key))
332: return -1;
333: }
334: return 0;
335: }
336:
337: /*
338: * Match keys against a specified key, or look one up by key type.
339: *
340: * If looking for a keytype (key == NULL) and one is found then return
341: * HOST_FOUND, otherwise HOST_NEW.
342: *
343: * If looking for a key (key != NULL):
344: * 1. If the key is a cert and a matching CA is found, return HOST_OK
345: * 2. If the key is not a cert and a matching key is found, return HOST_OK
346: * 3. If no key matches but a key with a different type is found, then
347: * return HOST_CHANGED
348: * 4. If no matching keys are found, then return HOST_NEW.
349: *
350: * Finally, check any found key is not revoked.
351: */
352: static HostStatus
353: check_hostkeys_by_key_or_type(struct hostkeys *hostkeys,
1.83 djm 354: struct sshkey *k, int keytype, int nid, const struct hostkey_entry **found)
1.49 djm 355: {
356: u_int i;
357: HostStatus end_return = HOST_NEW;
1.59 djm 358: int want_cert = sshkey_is_cert(k);
1.49 djm 359: HostkeyMarker want_marker = want_cert ? MRK_CA : MRK_NONE;
360:
361: if (found != NULL)
362: *found = NULL;
1.30 markus 363:
1.49 djm 364: for (i = 0; i < hostkeys->num_entries; i++) {
365: if (hostkeys->entries[i].marker != want_marker)
366: continue;
367: if (k == NULL) {
368: if (hostkeys->entries[i].key->type != keytype)
369: continue;
1.83 djm 370: if (nid != -1 &&
371: sshkey_type_plain(keytype) == KEY_ECDSA &&
372: hostkeys->entries[i].key->ecdsa_nid != nid)
373: continue;
1.49 djm 374: end_return = HOST_FOUND;
375: if (found != NULL)
376: *found = hostkeys->entries + i;
377: k = hostkeys->entries[i].key;
378: break;
379: }
380: if (want_cert) {
1.59 djm 381: if (sshkey_equal_public(k->cert->signature_key,
1.49 djm 382: hostkeys->entries[i].key)) {
383: /* A matching CA exists */
384: end_return = HOST_OK;
385: if (found != NULL)
386: *found = hostkeys->entries + i;
387: break;
1.48 djm 388: }
1.49 djm 389: } else {
1.59 djm 390: if (sshkey_equal(k, hostkeys->entries[i].key)) {
1.49 djm 391: end_return = HOST_OK;
392: if (found != NULL)
393: *found = hostkeys->entries + i;
394: break;
1.48 djm 395: }
1.49 djm 396: /* A non-maching key exists */
397: end_return = HOST_CHANGED;
398: if (found != NULL)
399: *found = hostkeys->entries + i;
1.48 djm 400: }
1.1 deraadt 401: }
1.49 djm 402: if (check_key_not_revoked(hostkeys, k) != 0) {
403: end_return = HOST_REVOKED;
404: if (found != NULL)
405: *found = NULL;
406: }
1.7 markus 407: return end_return;
1.30 markus 408: }
1.58 djm 409:
1.30 markus 410: HostStatus
1.59 djm 411: check_key_in_hostkeys(struct hostkeys *hostkeys, struct sshkey *key,
1.49 djm 412: const struct hostkey_entry **found)
1.30 markus 413: {
414: if (key == NULL)
415: fatal("no key to look up");
1.83 djm 416: return check_hostkeys_by_key_or_type(hostkeys, key, 0, -1, found);
1.30 markus 417: }
418:
419: int
1.83 djm 420: lookup_key_in_hostkeys_by_type(struct hostkeys *hostkeys, int keytype, int nid,
1.49 djm 421: const struct hostkey_entry **found)
1.30 markus 422: {
1.83 djm 423: return (check_hostkeys_by_key_or_type(hostkeys, NULL, keytype, nid,
1.49 djm 424: found) == HOST_FOUND);
1.80 djm 425: }
426:
427: int
428: lookup_marker_in_hostkeys(struct hostkeys *hostkeys, int want_marker)
429: {
430: u_int i;
431:
432: for (i = 0; i < hostkeys->num_entries; i++) {
433: if (hostkeys->entries[i].marker == (HostkeyMarker)want_marker)
434: return 1;
435: }
436: return 0;
1.1 deraadt 437: }
438:
1.62 djm 439: static int
1.64 djm 440: write_host_entry(FILE *f, const char *host, const char *ip,
1.62 djm 441: const struct sshkey *key, int store_hash)
442: {
443: int r, success = 0;
1.68 djm 444: char *hashed_host = NULL, *lhost;
445:
446: lhost = xstrdup(host);
447: lowercase(lhost);
1.62 djm 448:
449: if (store_hash) {
1.68 djm 450: if ((hashed_host = host_hash(lhost, NULL, 0)) == NULL) {
1.86 djm 451: error_f("host_hash failed");
1.68 djm 452: free(lhost);
1.62 djm 453: return 0;
454: }
1.64 djm 455: fprintf(f, "%s ", hashed_host);
456: } else if (ip != NULL)
1.68 djm 457: fprintf(f, "%s,%s ", lhost, ip);
458: else {
459: fprintf(f, "%s ", lhost);
460: }
461: free(lhost);
1.62 djm 462: if ((r = sshkey_write(key, f)) == 0)
463: success = 1;
464: else
1.86 djm 465: error_fr(r, "sshkey_write");
1.62 djm 466: fputc('\n', f);
1.84 djm 467: /* If hashing is enabled, the IP address needs to go on its own line */
468: if (success && store_hash && ip != NULL)
469: success = write_host_entry(f, ip, NULL, key, 1);
1.62 djm 470: return success;
471: }
472:
1.9 markus 473: /*
1.81 dtucker 474: * Create user ~/.ssh directory if it doesn't exist and we want to write to it.
475: * If notify is set, a message will be emitted if the directory is created.
476: */
477: void
478: hostfile_create_user_ssh_dir(const char *filename, int notify)
479: {
480: char *dotsshdir = NULL, *p;
481: size_t len;
482: struct stat st;
483:
484: if ((p = strrchr(filename, '/')) == NULL)
485: return;
486: len = p - filename;
487: dotsshdir = tilde_expand_filename("~/" _PATH_SSH_USER_DIR, getuid());
1.82 djm 488: if (strlen(dotsshdir) > len || strncmp(filename, dotsshdir, len) != 0)
489: goto out; /* not ~/.ssh prefixed */
490: if (stat(dotsshdir, &st) == 0)
491: goto out; /* dir already exists */
1.81 dtucker 492: else if (errno != ENOENT)
493: error("Could not stat %s: %s", dotsshdir, strerror(errno));
1.82 djm 494: else {
495: if (mkdir(dotsshdir, 0700) == -1)
496: error("Could not create directory '%.200s' (%s).",
497: dotsshdir, strerror(errno));
498: else if (notify)
499: logit("Created directory '%s'.", dotsshdir);
500: }
501: out:
1.81 dtucker 502: free(dotsshdir);
503: }
1.82 djm 504:
1.81 dtucker 505:
506: /*
1.9 markus 507: * Appends an entry to the host file. Returns false if the entry could not
508: * be appended.
509: */
1.2 provos 510: int
1.59 djm 511: add_host_to_hostfile(const char *filename, const char *host,
512: const struct sshkey *key, int store_hash)
1.1 deraadt 513: {
1.7 markus 514: FILE *f;
1.62 djm 515: int success;
1.33 djm 516:
1.14 markus 517: if (key == NULL)
1.17 markus 518: return 1; /* XXX ? */
1.81 dtucker 519: hostfile_create_user_ssh_dir(filename, 0);
1.7 markus 520: f = fopen(filename, "a");
521: if (!f)
522: return 0;
1.64 djm 523: success = write_host_entry(f, host, NULL, key, store_hash);
1.62 djm 524: fclose(f);
525: return success;
526: }
527:
528: struct host_delete_ctx {
529: FILE *out;
530: int quiet;
1.85 djm 531: const char *host, *ip;
532: u_int *match_keys; /* mask of HKF_MATCH_* for this key */
1.62 djm 533: struct sshkey * const *keys;
534: size_t nkeys;
1.64 djm 535: int modified;
1.62 djm 536: };
537:
538: static int
539: host_delete(struct hostkey_foreach_line *l, void *_ctx)
540: {
541: struct host_delete_ctx *ctx = (struct host_delete_ctx *)_ctx;
1.64 djm 542: int loglevel = ctx->quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE;
1.62 djm 543: size_t i;
544:
1.85 djm 545: /* Don't remove CA and revocation lines */
546: if (l->status == HKF_STATUS_MATCHED && l->marker == MRK_NONE) {
1.62 djm 547: /*
548: * If this line contains one of the keys that we will be
549: * adding later, then don't change it and mark the key for
550: * skipping.
551: */
552: for (i = 0; i < ctx->nkeys; i++) {
1.85 djm 553: if (!sshkey_equal(ctx->keys[i], l->key))
554: continue;
555: ctx->match_keys[i] |= l->match;
556: fprintf(ctx->out, "%s\n", l->line);
1.86 djm 557: debug3_f("%s key already at %s:%ld",
1.85 djm 558: sshkey_type(l->key), l->path, l->linenum);
559: return 0;
1.62 djm 560: }
561:
562: /*
563: * Hostname matches and has no CA/revoke marker, delete it
564: * by *not* writing the line to ctx->out.
565: */
1.64 djm 566: do_log2(loglevel, "%s%s%s:%ld: Removed %s key for host %s",
1.62 djm 567: ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "",
1.64 djm 568: l->path, l->linenum, sshkey_type(l->key), ctx->host);
569: ctx->modified = 1;
1.62 djm 570: return 0;
571: }
572: /* Retain non-matching hosts and invalid lines when deleting */
573: if (l->status == HKF_STATUS_INVALID) {
574: do_log2(loglevel, "%s%s%s:%ld: invalid known_hosts entry",
575: ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "",
576: l->path, l->linenum);
577: }
578: fprintf(ctx->out, "%s\n", l->line);
579: return 0;
580: }
581:
582: int
1.64 djm 583: hostfile_replace_entries(const char *filename, const char *host, const char *ip,
584: struct sshkey **keys, size_t nkeys, int store_hash, int quiet, int hash_alg)
1.62 djm 585: {
586: int r, fd, oerrno = 0;
1.64 djm 587: int loglevel = quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE;
1.62 djm 588: struct host_delete_ctx ctx;
1.64 djm 589: char *fp, *temp = NULL, *back = NULL;
1.85 djm 590: const char *what;
1.62 djm 591: mode_t omask;
592: size_t i;
1.85 djm 593: u_int want;
1.62 djm 594:
1.63 djm 595: omask = umask(077);
596:
1.62 djm 597: memset(&ctx, 0, sizeof(ctx));
598: ctx.host = host;
1.85 djm 599: ctx.ip = ip;
1.62 djm 600: ctx.quiet = quiet;
1.85 djm 601:
602: if ((ctx.match_keys = calloc(nkeys, sizeof(*ctx.match_keys))) == NULL)
1.62 djm 603: return SSH_ERR_ALLOC_FAIL;
604: ctx.keys = keys;
605: ctx.nkeys = nkeys;
1.64 djm 606: ctx.modified = 0;
1.62 djm 607:
608: /*
609: * Prepare temporary file for in-place deletion.
610: */
1.75 deraadt 611: if ((r = asprintf(&temp, "%s.XXXXXXXXXXX", filename)) == -1 ||
1.74 deraadt 612: (r = asprintf(&back, "%s.old", filename)) == -1) {
1.62 djm 613: r = SSH_ERR_ALLOC_FAIL;
614: goto fail;
615: }
616:
617: if ((fd = mkstemp(temp)) == -1) {
618: oerrno = errno;
1.86 djm 619: error_f("mkstemp: %s", strerror(oerrno));
1.62 djm 620: r = SSH_ERR_SYSTEM_ERROR;
621: goto fail;
622: }
623: if ((ctx.out = fdopen(fd, "w")) == NULL) {
624: oerrno = errno;
625: close(fd);
1.86 djm 626: error_f("fdopen: %s", strerror(oerrno));
1.62 djm 627: r = SSH_ERR_SYSTEM_ERROR;
628: goto fail;
629: }
630:
1.85 djm 631: /* Remove stale/mismatching entries for the specified host */
1.64 djm 632: if ((r = hostkeys_foreach(filename, host_delete, &ctx, host, ip,
1.87 ! djm 633: HKF_WANT_PARSE_KEY, 0)) != 0) {
1.77 djm 634: oerrno = errno;
1.86 djm 635: error_fr(r, "hostkeys_foreach");
1.62 djm 636: goto fail;
637: }
638:
1.85 djm 639: /* Re-add the requested keys */
640: want = HKF_MATCH_HOST | (ip == NULL ? 0 : HKF_MATCH_IP);
1.62 djm 641: for (i = 0; i < nkeys; i++) {
1.85 djm 642: if ((want & ctx.match_keys[i]) == want)
1.62 djm 643: continue;
1.64 djm 644: if ((fp = sshkey_fingerprint(keys[i], hash_alg,
645: SSH_FP_DEFAULT)) == NULL) {
646: r = SSH_ERR_ALLOC_FAIL;
647: goto fail;
648: }
1.85 djm 649: /* write host/ip */
650: what = "";
651: if (ctx.match_keys[i] == 0) {
652: what = "Adding new key";
653: if (!write_host_entry(ctx.out, host, ip,
654: keys[i], store_hash)) {
655: r = SSH_ERR_INTERNAL_ERROR;
656: goto fail;
657: }
658: } else if ((want & ~ctx.match_keys[i]) == HKF_MATCH_HOST) {
659: what = "Fixing match (hostname)";
660: if (!write_host_entry(ctx.out, host, NULL,
661: keys[i], store_hash)) {
662: r = SSH_ERR_INTERNAL_ERROR;
663: goto fail;
664: }
665: } else if ((want & ~ctx.match_keys[i]) == HKF_MATCH_IP) {
666: what = "Fixing match (address)";
667: if (!write_host_entry(ctx.out, ip, NULL,
668: keys[i], store_hash)) {
669: r = SSH_ERR_INTERNAL_ERROR;
670: goto fail;
671: }
672: }
673: do_log2(loglevel, "%s%s%s for %s%s%s to %s: %s %s",
674: quiet ? __func__ : "", quiet ? ": " : "", what,
675: host, ip == NULL ? "" : ",", ip == NULL ? "" : ip, filename,
1.64 djm 676: sshkey_ssh_name(keys[i]), fp);
677: free(fp);
678: ctx.modified = 1;
1.33 djm 679: }
1.62 djm 680: fclose(ctx.out);
681: ctx.out = NULL;
1.33 djm 682:
1.64 djm 683: if (ctx.modified) {
684: /* Backup the original file and replace it with the temporary */
685: if (unlink(back) == -1 && errno != ENOENT) {
686: oerrno = errno;
1.86 djm 687: error_f("unlink %.100s: %s", back, strerror(errno));
1.64 djm 688: r = SSH_ERR_SYSTEM_ERROR;
689: goto fail;
690: }
691: if (link(filename, back) == -1) {
692: oerrno = errno;
1.86 djm 693: error_f("link %.100s to %.100s: %s", filename,
694: back, strerror(errno));
1.64 djm 695: r = SSH_ERR_SYSTEM_ERROR;
696: goto fail;
697: }
698: if (rename(temp, filename) == -1) {
699: oerrno = errno;
1.86 djm 700: error_f("rename \"%s\" to \"%s\": %s", temp,
701: filename, strerror(errno));
1.64 djm 702: r = SSH_ERR_SYSTEM_ERROR;
703: goto fail;
704: }
705: } else {
706: /* No changes made; just delete the temporary file */
707: if (unlink(temp) != 0)
1.86 djm 708: error_f("unlink \"%s\": %s", temp, strerror(errno));
1.62 djm 709: }
1.64 djm 710:
1.62 djm 711: /* success */
712: r = 0;
713: fail:
714: if (temp != NULL && r != 0)
715: unlink(temp);
716: free(temp);
717: free(back);
718: if (ctx.out != NULL)
719: fclose(ctx.out);
1.85 djm 720: free(ctx.match_keys);
1.63 djm 721: umask(omask);
1.62 djm 722: if (r == SSH_ERR_SYSTEM_ERROR)
723: errno = oerrno;
724: return r;
1.60 djm 725: }
726:
727: static int
728: match_maybe_hashed(const char *host, const char *names, int *was_hashed)
729: {
730: int hashed = *names == HASH_DELIM;
731: const char *hashed_host;
732: size_t nlen = strlen(names);
733:
734: if (was_hashed != NULL)
735: *was_hashed = hashed;
736: if (hashed) {
737: if ((hashed_host = host_hash(host, names, nlen)) == NULL)
738: return -1;
739: return nlen == strlen(hashed_host) &&
740: strncmp(hashed_host, names, nlen) == 0;
741: }
1.66 djm 742: return match_hostname(host, names) == 1;
1.60 djm 743: }
744:
745: int
1.87 ! djm 746: hostkeys_foreach_file(const char *path, FILE *f, hostkeys_foreach_fn *callback,
! 747: void *ctx, const char *host, const char *ip, u_int options, u_int note)
1.60 djm 748: {
1.72 markus 749: char *line = NULL, ktype[128];
1.60 djm 750: u_long linenum = 0;
751: char *cp, *cp2;
752: u_int kbits;
1.64 djm 753: int hashed;
1.60 djm 754: int s, r = 0;
755: struct hostkey_foreach_line lineinfo;
1.72 markus 756: size_t linesize = 0, l;
1.60 djm 757:
758: memset(&lineinfo, 0, sizeof(lineinfo));
1.64 djm 759: if (host == NULL && (options & HKF_WANT_MATCH) != 0)
1.60 djm 760: return SSH_ERR_INVALID_ARGUMENT;
761:
1.72 markus 762: while (getline(&line, &linesize, f) != -1) {
763: linenum++;
1.60 djm 764: line[strcspn(line, "\n")] = '\0';
765:
1.73 djm 766: free(lineinfo.line);
1.60 djm 767: sshkey_free(lineinfo.key);
768: memset(&lineinfo, 0, sizeof(lineinfo));
769: lineinfo.path = path;
770: lineinfo.linenum = linenum;
1.72 markus 771: lineinfo.line = xstrdup(line);
1.64 djm 772: lineinfo.marker = MRK_NONE;
1.60 djm 773: lineinfo.status = HKF_STATUS_OK;
1.64 djm 774: lineinfo.keytype = KEY_UNSPEC;
1.87 ! djm 775: lineinfo.note = note;
1.60 djm 776:
777: /* Skip any leading whitespace, comments and empty lines. */
778: for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
779: ;
780: if (!*cp || *cp == '#' || *cp == '\n') {
1.64 djm 781: if ((options & HKF_WANT_MATCH) == 0) {
1.60 djm 782: lineinfo.status = HKF_STATUS_COMMENT;
783: if ((r = callback(&lineinfo, ctx)) != 0)
784: break;
785: }
786: continue;
787: }
788:
789: if ((lineinfo.marker = check_markers(&cp)) == MRK_ERROR) {
1.86 djm 790: verbose_f("invalid marker at %s:%lu", path, linenum);
1.64 djm 791: if ((options & HKF_WANT_MATCH) == 0)
1.60 djm 792: goto bad;
793: continue;
794: }
795:
796: /* Find the end of the host name portion. */
797: for (cp2 = cp; *cp2 && *cp2 != ' ' && *cp2 != '\t'; cp2++)
798: ;
799: lineinfo.hosts = cp;
800: *cp2++ = '\0';
801:
802: /* Check if the host name matches. */
803: if (host != NULL) {
1.64 djm 804: if ((s = match_maybe_hashed(host, lineinfo.hosts,
805: &hashed)) == -1) {
1.86 djm 806: debug2_f("%s:%ld: bad host hash \"%.32s\"",
807: path, linenum, lineinfo.hosts);
1.60 djm 808: goto bad;
809: }
1.64 djm 810: if (s == 1) {
811: lineinfo.status = HKF_STATUS_MATCHED;
812: lineinfo.match |= HKF_MATCH_HOST |
813: (hashed ? HKF_MATCH_HOST_HASHED : 0);
814: }
815: /* Try matching IP address if supplied */
816: if (ip != NULL) {
817: if ((s = match_maybe_hashed(ip, lineinfo.hosts,
818: &hashed)) == -1) {
1.86 djm 819: debug2_f("%s:%ld: bad ip hash "
820: "\"%.32s\"", path, linenum,
821: lineinfo.hosts);
1.64 djm 822: goto bad;
823: }
824: if (s == 1) {
825: lineinfo.status = HKF_STATUS_MATCHED;
826: lineinfo.match |= HKF_MATCH_IP |
827: (hashed ? HKF_MATCH_IP_HASHED : 0);
828: }
829: }
830: /*
831: * Skip this line if host matching requested and
832: * neither host nor address matched.
833: */
834: if ((options & HKF_WANT_MATCH) != 0 &&
835: lineinfo.status != HKF_STATUS_MATCHED)
836: continue;
1.60 djm 837: }
838:
839: /* Got a match. Skip host name and any following whitespace */
840: for (; *cp2 == ' ' || *cp2 == '\t'; cp2++)
841: ;
842: if (*cp2 == '\0' || *cp2 == '#') {
1.64 djm 843: debug2("%s:%ld: truncated before key type",
844: path, linenum);
1.60 djm 845: goto bad;
846: }
847: lineinfo.rawkey = cp = cp2;
848:
849: if ((options & HKF_WANT_PARSE_KEY) != 0) {
850: /*
851: * Extract the key from the line. This will skip
852: * any leading whitespace. Ignore badly formatted
853: * lines.
854: */
855: if ((lineinfo.key = sshkey_new(KEY_UNSPEC)) == NULL) {
1.86 djm 856: error_f("sshkey_new failed");
1.64 djm 857: r = SSH_ERR_ALLOC_FAIL;
858: break;
1.60 djm 859: }
860: if (!hostfile_read_key(&cp, &kbits, lineinfo.key)) {
861: goto bad;
862: }
1.64 djm 863: lineinfo.keytype = lineinfo.key->type;
864: lineinfo.comment = cp;
865: } else {
866: /* Extract and parse key type */
867: l = strcspn(lineinfo.rawkey, " \t");
868: if (l <= 1 || l >= sizeof(ktype) ||
869: lineinfo.rawkey[l] == '\0')
870: goto bad;
871: memcpy(ktype, lineinfo.rawkey, l);
872: ktype[l] = '\0';
873: lineinfo.keytype = sshkey_type_from_name(ktype);
1.65 djm 874:
1.64 djm 875: /*
1.70 djm 876: * Assume legacy RSA1 if the first component is a short
1.64 djm 877: * decimal number.
878: */
879: if (lineinfo.keytype == KEY_UNSPEC && l < 8 &&
880: strspn(ktype, "0123456789") == l)
1.70 djm 881: goto bad;
1.65 djm 882:
1.64 djm 883: /*
884: * Check that something other than whitespace follows
885: * the key type. This won't catch all corruption, but
886: * it does catch trivial truncation.
887: */
888: cp2 += l; /* Skip past key type */
889: for (; *cp2 == ' ' || *cp2 == '\t'; cp2++)
890: ;
891: if (*cp2 == '\0' || *cp2 == '#') {
892: debug2("%s:%ld: truncated after key type",
893: path, linenum);
894: lineinfo.keytype = KEY_UNSPEC;
895: }
896: if (lineinfo.keytype == KEY_UNSPEC) {
1.60 djm 897: bad:
1.64 djm 898: sshkey_free(lineinfo.key);
899: lineinfo.key = NULL;
1.60 djm 900: lineinfo.status = HKF_STATUS_INVALID;
901: if ((r = callback(&lineinfo, ctx)) != 0)
902: break;
903: continue;
904: }
905: }
906: if ((r = callback(&lineinfo, ctx)) != 0)
907: break;
908: }
909: sshkey_free(lineinfo.key);
1.72 markus 910: free(lineinfo.line);
911: free(line);
1.87 ! djm 912: return r;
! 913: }
! 914:
! 915: int
! 916: hostkeys_foreach(const char *path, hostkeys_foreach_fn *callback, void *ctx,
! 917: const char *host, const char *ip, u_int options, u_int note)
! 918: {
! 919: FILE *f;
! 920: int r, oerrno;
! 921:
! 922: if ((f = fopen(path, "r")) == NULL)
! 923: return SSH_ERR_SYSTEM_ERROR;
! 924:
! 925: debug3_f("reading file \"%s\"", path);
! 926: r = hostkeys_foreach_file(path, f, callback, ctx, host, ip,
! 927: options, note);
! 928: oerrno = errno;
1.60 djm 929: fclose(f);
1.87 ! djm 930: errno = oerrno;
1.60 djm 931: return r;
1.1 deraadt 932: }