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authordjm@openbsd.org <djm@openbsd.org>2015-02-16 22:08:57 +0000
committerDamien Miller <djm@mindrot.org>2015-02-17 09:32:31 +1100
commit6c5c949782d86a6e7d58006599c7685bfcd01685 (patch)
tree7a3f58c507d8aacaefae9880bcfcc924aa2b891b /hostfile.c
parent51b082ccbe633dc970df1d1f4c9c0497115fe721 (diff)
upstream commit
Refactor hostkeys_foreach() and dependent code Deal with IP addresses (i.e. CheckHostIP) Don't clobber known_hosts when nothing changed ok markus@ as part of larger commit
Diffstat (limited to 'hostfile.c')
-rw-r--r--hostfile.c219
1 files changed, 143 insertions, 76 deletions
diff --git a/hostfile.c b/hostfile.c
index ea6bc6fc..b235795e 100644
--- a/hostfile.c
+++ b/hostfile.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: hostfile.c,v 1.63 2015/01/26 13:36:53 djm Exp $ */
+/* $OpenBSD: hostfile.c,v 1.64 2015/02/16 22:08:57 djm Exp $ */
/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -184,24 +184,6 @@ hostfile_read_key(char **cpp, u_int *bitsp, struct sshkey *ret)
return 1;
}
-static int
-hostfile_check_key(int bits, const struct sshkey *key, const char *host,
- const char *filename, u_long linenum)
-{
-#ifdef WITH_SSH1
- if (key == NULL || key->type != KEY_RSA1 || key->rsa == NULL)
- return 1;
- if (bits != BN_num_bits(key->rsa->n)) {
- logit("Warning: %s, line %lu: keysize mismatch for host %s: "
- "actual %d vs. announced %d.",
- filename, linenum, host, BN_num_bits(key->rsa->n), bits);
- logit("Warning: replace %d with %d in %s, line %lu.",
- bits, BN_num_bits(key->rsa->n), filename, linenum);
- }
-#endif
- return 1;
-}
-
static HostkeyMarker
check_markers(char **cpp)
{
@@ -295,8 +277,8 @@ load_hostkeys(struct hostkeys *hostkeys, const char *host, const char *path)
ctx.num_loaded = 0;
ctx.hostkeys = hostkeys;
- if ((r = hostkeys_foreach(path, record_hostkey, &ctx, host,
- HKF_WANT_MATCH_HOST|HKF_WANT_PARSE_KEY)) != 0) {
+ if ((r = hostkeys_foreach(path, record_hostkey, &ctx, host, NULL,
+ HKF_WANT_MATCH|HKF_WANT_PARSE_KEY)) != 0) {
if (r != SSH_ERR_SYSTEM_ERROR && errno != ENOENT)
debug("%s: hostkeys_foreach failed for %s: %s",
__func__, path, ssh_err(r));
@@ -433,7 +415,7 @@ lookup_key_in_hostkeys_by_type(struct hostkeys *hostkeys, int keytype,
}
static int
-write_host_entry(FILE *f, const char *host,
+write_host_entry(FILE *f, const char *host, const char *ip,
const struct sshkey *key, int store_hash)
{
int r, success = 0;
@@ -444,8 +426,11 @@ write_host_entry(FILE *f, const char *host,
error("%s: host_hash failed", __func__);
return 0;
}
- }
- fprintf(f, "%s ", store_hash ? hashed_host : host);
+ fprintf(f, "%s ", hashed_host);
+ } else if (ip != NULL)
+ fprintf(f, "%s,%s ", host, ip);
+ else
+ fprintf(f, "%s ", host);
if ((r = sshkey_write(key, f)) == 0)
success = 1;
@@ -471,7 +456,7 @@ add_host_to_hostfile(const char *filename, const char *host,
f = fopen(filename, "a");
if (!f)
return 0;
- success = write_host_entry(f, host, key, store_hash);
+ success = write_host_entry(f, host, NULL, key, store_hash);
fclose(f);
return success;
}
@@ -480,19 +465,20 @@ struct host_delete_ctx {
FILE *out;
int quiet;
const char *host;
- int *skip_keys;
+ int *skip_keys; /* XXX split for host/ip? might want to ensure both */
struct sshkey * const *keys;
size_t nkeys;
+ int modified;
};
static int
host_delete(struct hostkey_foreach_line *l, void *_ctx)
{
struct host_delete_ctx *ctx = (struct host_delete_ctx *)_ctx;
- int loglevel = ctx->quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_INFO;
+ int loglevel = ctx->quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE;
size_t i;
- if (l->status == HKF_STATUS_HOST_MATCHED) {
+ if (l->status == HKF_STATUS_MATCHED) {
if (l->marker != MRK_NONE) {
/* Don't remove CA and revocation lines */
fprintf(ctx->out, "%s\n", l->line);
@@ -525,9 +511,10 @@ host_delete(struct hostkey_foreach_line *l, void *_ctx)
* Hostname matches and has no CA/revoke marker, delete it
* by *not* writing the line to ctx->out.
*/
- do_log2(loglevel, "%s%s%s:%ld: Host %s removed",
+ do_log2(loglevel, "%s%s%s:%ld: Removed %s key for host %s",
ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "",
- l->path, l->linenum, ctx->host);
+ l->path, l->linenum, sshkey_type(l->key), ctx->host);
+ ctx->modified = 1;
return 0;
}
/* Retain non-matching hosts and invalid lines when deleting */
@@ -541,13 +528,13 @@ host_delete(struct hostkey_foreach_line *l, void *_ctx)
}
int
-hostfile_replace_entries(const char *filename, const char *host,
- struct sshkey **keys, size_t nkeys, int store_hash, int quiet)
+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)
{
int r, fd, oerrno = 0;
- int loglevel = quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_INFO;
+ int loglevel = quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE;
struct host_delete_ctx ctx;
- char *temp = NULL, *back = NULL;
+ char *fp, *temp = NULL, *back = NULL;
mode_t omask;
size_t i;
@@ -560,6 +547,7 @@ hostfile_replace_entries(const char *filename, const char *host,
return SSH_ERR_ALLOC_FAIL;
ctx.keys = keys;
ctx.nkeys = nkeys;
+ ctx.modified = 0;
/*
* Prepare temporary file for in-place deletion.
@@ -585,7 +573,7 @@ hostfile_replace_entries(const char *filename, const char *host,
}
/* Remove all entries for the specified host from the file */
- if ((r = hostkeys_foreach(filename, host_delete, &ctx, host,
+ if ((r = hostkeys_foreach(filename, host_delete, &ctx, host, ip,
HKF_WANT_PARSE_KEY)) != 0) {
error("%s: hostkeys_foreach failed: %s", __func__, ssh_err(r));
goto fail;
@@ -595,38 +583,54 @@ hostfile_replace_entries(const char *filename, const char *host,
for (i = 0; i < nkeys; i++) {
if (ctx.skip_keys[i])
continue;
- do_log2(loglevel, "%s%sadd %s key to %s",
- quiet ? __func__ : "", quiet ? ": " : NULL,
- sshkey_type(keys[i]), filename);
- if (!write_host_entry(ctx.out, host, keys[i], store_hash)) {
+ if ((fp = sshkey_fingerprint(keys[i], hash_alg,
+ SSH_FP_DEFAULT)) == NULL) {
+ r = SSH_ERR_ALLOC_FAIL;
+ goto fail;
+ }
+ do_log2(loglevel, "%s%sAdding new key for %s to %s: %s %s",
+ quiet ? __func__ : "", quiet ? ": " : "", host, filename,
+ sshkey_ssh_name(keys[i]), fp);
+ free(fp);
+ if (!write_host_entry(ctx.out, host, ip, keys[i], store_hash)) {
r = SSH_ERR_INTERNAL_ERROR;
goto fail;
}
+ ctx.modified = 1;
}
fclose(ctx.out);
ctx.out = NULL;
- /* Backup the original file and replace it with the temporary */
- if (unlink(back) == -1 && errno != ENOENT) {
- oerrno = errno;
- error("%s: unlink %.100s: %s", __func__, back, strerror(errno));
- r = SSH_ERR_SYSTEM_ERROR;
- goto fail;
- }
- if (link(filename, back) == -1) {
- oerrno = errno;
- error("%s: link %.100s to %.100s: %s", __func__, filename, back,
- strerror(errno));
- r = SSH_ERR_SYSTEM_ERROR;
- goto fail;
- }
- if (rename(temp, filename) == -1) {
- oerrno = errno;
- error("%s: rename \"%s\" to \"%s\": %s", __func__,
- temp, filename, strerror(errno));
- r = SSH_ERR_SYSTEM_ERROR;
- goto fail;
+ if (ctx.modified) {
+ /* Backup the original file and replace it with the temporary */
+ if (unlink(back) == -1 && errno != ENOENT) {
+ oerrno = errno;
+ error("%s: unlink %.100s: %s", __func__,
+ back, strerror(errno));
+ r = SSH_ERR_SYSTEM_ERROR;
+ goto fail;
+ }
+ if (link(filename, back) == -1) {
+ oerrno = errno;
+ error("%s: link %.100s to %.100s: %s", __func__,
+ filename, back, strerror(errno));
+ r = SSH_ERR_SYSTEM_ERROR;
+ goto fail;
+ }
+ if (rename(temp, filename) == -1) {
+ oerrno = errno;
+ error("%s: rename \"%s\" to \"%s\": %s", __func__,
+ temp, filename, strerror(errno));
+ r = SSH_ERR_SYSTEM_ERROR;
+ goto fail;
+ }
+ } else {
+ /* No changes made; just delete the temporary file */
+ if (unlink(temp) != 0)
+ error("%s: unlink \"%s\": %s", __func__,
+ temp, strerror(errno));
}
+
/* success */
r = 0;
fail:
@@ -663,18 +667,20 @@ match_maybe_hashed(const char *host, const char *names, int *was_hashed)
int
hostkeys_foreach(const char *path, hostkeys_foreach_fn *callback, void *ctx,
- const char *host, u_int options)
+ const char *host, const char *ip, u_int options)
{
FILE *f;
- char line[8192], oline[8192];
+ char line[8192], oline[8192], ktype[128];
u_long linenum = 0;
char *cp, *cp2;
u_int kbits;
+ int hashed;
int s, r = 0;
struct hostkey_foreach_line lineinfo;
+ size_t l;
memset(&lineinfo, 0, sizeof(lineinfo));
- if (host == NULL && (options & HKF_WANT_MATCH_HOST) != 0)
+ if (host == NULL && (options & HKF_WANT_MATCH) != 0)
return SSH_ERR_INVALID_ARGUMENT;
if ((f = fopen(path, "r")) == NULL)
return SSH_ERR_SYSTEM_ERROR;
@@ -689,13 +695,15 @@ hostkeys_foreach(const char *path, hostkeys_foreach_fn *callback, void *ctx,
lineinfo.path = path;
lineinfo.linenum = linenum;
lineinfo.line = oline;
+ lineinfo.marker = MRK_NONE;
lineinfo.status = HKF_STATUS_OK;
+ lineinfo.keytype = KEY_UNSPEC;
/* Skip any leading whitespace, comments and empty lines. */
for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
;
if (!*cp || *cp == '#' || *cp == '\n') {
- if ((options & HKF_WANT_MATCH_HOST) == 0) {
+ if ((options & HKF_WANT_MATCH) == 0) {
lineinfo.status = HKF_STATUS_COMMENT;
if ((r = callback(&lineinfo, ctx)) != 0)
break;
@@ -706,7 +714,7 @@ hostkeys_foreach(const char *path, hostkeys_foreach_fn *callback, void *ctx,
if ((lineinfo.marker = check_markers(&cp)) == MRK_ERROR) {
verbose("%s: invalid marker at %s:%lu",
__func__, path, linenum);
- if ((options & HKF_WANT_MATCH_HOST) == 0)
+ if ((options & HKF_WANT_MATCH) == 0)
goto bad;
continue;
}
@@ -719,24 +727,47 @@ hostkeys_foreach(const char *path, hostkeys_foreach_fn *callback, void *ctx,
/* Check if the host name matches. */
if (host != NULL) {
- s = match_maybe_hashed(host, lineinfo.hosts,
- &lineinfo.was_hashed);
- if (s == 1)
- lineinfo.status = HKF_STATUS_HOST_MATCHED;
- else if ((options & HKF_WANT_MATCH_HOST) != 0)
- continue;
- else if (s == -1) {
+ if ((s = match_maybe_hashed(host, lineinfo.hosts,
+ &hashed)) == -1) {
debug2("%s: %s:%ld: bad host hash \"%.32s\"",
__func__, path, linenum, lineinfo.hosts);
goto bad;
}
+ if (s == 1) {
+ lineinfo.status = HKF_STATUS_MATCHED;
+ lineinfo.match |= HKF_MATCH_HOST |
+ (hashed ? HKF_MATCH_HOST_HASHED : 0);
+ }
+ /* Try matching IP address if supplied */
+ if (ip != NULL) {
+ if ((s = match_maybe_hashed(ip, lineinfo.hosts,
+ &hashed)) == -1) {
+ debug2("%s: %s:%ld: bad ip hash "
+ "\"%.32s\"", __func__, path,
+ linenum, lineinfo.hosts);
+ goto bad;
+ }
+ if (s == 1) {
+ lineinfo.status = HKF_STATUS_MATCHED;
+ lineinfo.match |= HKF_MATCH_IP |
+ (hashed ? HKF_MATCH_IP_HASHED : 0);
+ }
+ }
+ /*
+ * Skip this line if host matching requested and
+ * neither host nor address matched.
+ */
+ if ((options & HKF_WANT_MATCH) != 0 &&
+ lineinfo.status != HKF_STATUS_MATCHED)
+ continue;
}
/* Got a match. Skip host name and any following whitespace */
for (; *cp2 == ' ' || *cp2 == '\t'; cp2++)
;
if (*cp2 == '\0' || *cp2 == '#') {
- debug2("%s:%ld: truncated before key", path, linenum);
+ debug2("%s:%ld: truncated before key type",
+ path, linenum);
goto bad;
}
lineinfo.rawkey = cp = cp2;
@@ -749,7 +780,8 @@ hostkeys_foreach(const char *path, hostkeys_foreach_fn *callback, void *ctx,
*/
if ((lineinfo.key = sshkey_new(KEY_UNSPEC)) == NULL) {
error("%s: sshkey_new failed", __func__);
- return SSH_ERR_ALLOC_FAIL;
+ r = SSH_ERR_ALLOC_FAIL;
+ break;
}
if (!hostfile_read_key(&cp, &kbits, lineinfo.key)) {
#ifdef WITH_SSH1
@@ -757,7 +789,8 @@ hostkeys_foreach(const char *path, hostkeys_foreach_fn *callback, void *ctx,
lineinfo.key = sshkey_new(KEY_RSA1);
if (lineinfo.key == NULL) {
error("%s: sshkey_new fail", __func__);
- return SSH_ERR_ALLOC_FAIL;
+ r = SSH_ERR_ALLOC_FAIL;
+ break;
}
if (!hostfile_read_key(&cp, &kbits,
lineinfo.key))
@@ -766,9 +799,43 @@ hostkeys_foreach(const char *path, hostkeys_foreach_fn *callback, void *ctx,
goto bad;
#endif
}
- if (!hostfile_check_key(kbits, lineinfo.key, host,
- path, linenum)) {
+ lineinfo.keytype = lineinfo.key->type;
+ lineinfo.comment = cp;
+ } else {
+ /* Extract and parse key type */
+ l = strcspn(lineinfo.rawkey, " \t");
+ if (l <= 1 || l >= sizeof(ktype) ||
+ lineinfo.rawkey[l] == '\0')
+ goto bad;
+ memcpy(ktype, lineinfo.rawkey, l);
+ ktype[l] = '\0';
+ lineinfo.keytype = sshkey_type_from_name(ktype);
+#ifdef WITH_SSH1
+ /*
+ * Assume RSA1 if the first component is a short
+ * decimal number.
+ */
+ if (lineinfo.keytype == KEY_UNSPEC && l < 8 &&
+ strspn(ktype, "0123456789") == l)
+ lineinfo.keytype = KEY_RSA1;
+#endif
+ /*
+ * Check that something other than whitespace follows
+ * the key type. This won't catch all corruption, but
+ * it does catch trivial truncation.
+ */
+ cp2 += l; /* Skip past key type */
+ for (; *cp2 == ' ' || *cp2 == '\t'; cp2++)
+ ;
+ if (*cp2 == '\0' || *cp2 == '#') {
+ debug2("%s:%ld: truncated after key type",
+ path, linenum);
+ lineinfo.keytype = KEY_UNSPEC;
+ }
+ if (lineinfo.keytype == KEY_UNSPEC) {
bad:
+ sshkey_free(lineinfo.key);
+ lineinfo.key = NULL;
lineinfo.status = HKF_STATUS_INVALID;
if ((r = callback(&lineinfo, ctx)) != 0)
break;