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-rw-r--r--hostfile.c884
1 files changed, 884 insertions, 0 deletions
diff --git a/hostfile.c b/hostfile.c
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index 0000000..936d8c9
--- /dev/null
+++ b/hostfile.c
@@ -0,0 +1,884 @@
+/* $OpenBSD: hostfile.c,v 1.82 2020/06/26 05:42:16 djm Exp $ */
+/*
+ * Author: Tatu Ylonen <ylo@cs.hut.fi>
+ * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
+ * All rights reserved
+ * Functions for manipulating the known hosts files.
+ *
+ * As far as I am concerned, the code I have written for this software
+ * can be used freely for any purpose. Any derived versions of this
+ * software must be clearly marked as such, and if the derived work is
+ * incompatible with the protocol description in the RFC file, it must be
+ * called by a name other than "ssh" or "Secure Shell".
+ *
+ *
+ * Copyright (c) 1999, 2000 Markus Friedl. All rights reserved.
+ * Copyright (c) 1999 Niels Provos. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "includes.h"
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <netinet/in.h>
+
+#include <errno.h>
+#include <resolv.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "xmalloc.h"
+#include "match.h"
+#include "sshkey.h"
+#include "hostfile.h"
+#include "log.h"
+#include "misc.h"
+#include "pathnames.h"
+#include "ssherr.h"
+#include "digest.h"
+#include "hmac.h"
+
+struct hostkeys {
+ struct hostkey_entry *entries;
+ u_int num_entries;
+};
+
+/* XXX hmac is too easy to dictionary attack; use bcrypt? */
+
+static int
+extract_salt(const char *s, u_int l, u_char *salt, size_t salt_len)
+{
+ char *p, *b64salt;
+ u_int b64len;
+ int ret;
+
+ if (l < sizeof(HASH_MAGIC) - 1) {
+ debug2("extract_salt: string too short");
+ return (-1);
+ }
+ if (strncmp(s, HASH_MAGIC, sizeof(HASH_MAGIC) - 1) != 0) {
+ debug2("extract_salt: invalid magic identifier");
+ return (-1);
+ }
+ s += sizeof(HASH_MAGIC) - 1;
+ l -= sizeof(HASH_MAGIC) - 1;
+ if ((p = memchr(s, HASH_DELIM, l)) == NULL) {
+ debug2("extract_salt: missing salt termination character");
+ return (-1);
+ }
+
+ b64len = p - s;
+ /* Sanity check */
+ if (b64len == 0 || b64len > 1024) {
+ debug2("extract_salt: bad encoded salt length %u", b64len);
+ return (-1);
+ }
+ b64salt = xmalloc(1 + b64len);
+ memcpy(b64salt, s, b64len);
+ b64salt[b64len] = '\0';
+
+ ret = __b64_pton(b64salt, salt, salt_len);
+ free(b64salt);
+ if (ret == -1) {
+ debug2("extract_salt: salt decode error");
+ return (-1);
+ }
+ if (ret != (int)ssh_hmac_bytes(SSH_DIGEST_SHA1)) {
+ debug2("extract_salt: expected salt len %zd, got %d",
+ ssh_hmac_bytes(SSH_DIGEST_SHA1), ret);
+ return (-1);
+ }
+
+ return (0);
+}
+
+char *
+host_hash(const char *host, const char *name_from_hostfile, u_int src_len)
+{
+ struct ssh_hmac_ctx *ctx;
+ u_char salt[256], result[256];
+ char uu_salt[512], uu_result[512];
+ static char encoded[1024];
+ u_int len;
+
+ len = ssh_digest_bytes(SSH_DIGEST_SHA1);
+
+ if (name_from_hostfile == NULL) {
+ /* Create new salt */
+ arc4random_buf(salt, len);
+ } else {
+ /* Extract salt from known host entry */
+ if (extract_salt(name_from_hostfile, src_len, salt,
+ sizeof(salt)) == -1)
+ return (NULL);
+ }
+
+ if ((ctx = ssh_hmac_start(SSH_DIGEST_SHA1)) == NULL ||
+ ssh_hmac_init(ctx, salt, len) < 0 ||
+ ssh_hmac_update(ctx, host, strlen(host)) < 0 ||
+ ssh_hmac_final(ctx, result, sizeof(result)))
+ fatal("%s: ssh_hmac failed", __func__);
+ ssh_hmac_free(ctx);
+
+ if (__b64_ntop(salt, len, uu_salt, sizeof(uu_salt)) == -1 ||
+ __b64_ntop(result, len, uu_result, sizeof(uu_result)) == -1)
+ fatal("%s: __b64_ntop failed", __func__);
+
+ snprintf(encoded, sizeof(encoded), "%s%s%c%s", HASH_MAGIC, uu_salt,
+ HASH_DELIM, uu_result);
+
+ return (encoded);
+}
+
+/*
+ * Parses an RSA (number of bits, e, n) or DSA key from a string. Moves the
+ * pointer over the key. Skips any whitespace at the beginning and at end.
+ */
+
+int
+hostfile_read_key(char **cpp, u_int *bitsp, struct sshkey *ret)
+{
+ char *cp;
+
+ /* Skip leading whitespace. */
+ for (cp = *cpp; *cp == ' ' || *cp == '\t'; cp++)
+ ;
+
+ if (sshkey_read(ret, &cp) != 0)
+ return 0;
+
+ /* Skip trailing whitespace. */
+ for (; *cp == ' ' || *cp == '\t'; cp++)
+ ;
+
+ /* Return results. */
+ *cpp = cp;
+ if (bitsp != NULL)
+ *bitsp = sshkey_size(ret);
+ return 1;
+}
+
+static HostkeyMarker
+check_markers(char **cpp)
+{
+ char marker[32], *sp, *cp = *cpp;
+ int ret = MRK_NONE;
+
+ while (*cp == '@') {
+ /* Only one marker is allowed */
+ if (ret != MRK_NONE)
+ return MRK_ERROR;
+ /* Markers are terminated by whitespace */
+ if ((sp = strchr(cp, ' ')) == NULL &&
+ (sp = strchr(cp, '\t')) == NULL)
+ return MRK_ERROR;
+ /* Extract marker for comparison */
+ if (sp <= cp + 1 || sp >= cp + sizeof(marker))
+ return MRK_ERROR;
+ memcpy(marker, cp, sp - cp);
+ marker[sp - cp] = '\0';
+ if (strcmp(marker, CA_MARKER) == 0)
+ ret = MRK_CA;
+ else if (strcmp(marker, REVOKE_MARKER) == 0)
+ ret = MRK_REVOKE;
+ else
+ return MRK_ERROR;
+
+ /* Skip past marker and any whitespace that follows it */
+ cp = sp;
+ for (; *cp == ' ' || *cp == '\t'; cp++)
+ ;
+ }
+ *cpp = cp;
+ return ret;
+}
+
+struct hostkeys *
+init_hostkeys(void)
+{
+ struct hostkeys *ret = xcalloc(1, sizeof(*ret));
+
+ ret->entries = NULL;
+ return ret;
+}
+
+struct load_callback_ctx {
+ const char *host;
+ u_long num_loaded;
+ struct hostkeys *hostkeys;
+};
+
+static int
+record_hostkey(struct hostkey_foreach_line *l, void *_ctx)
+{
+ struct load_callback_ctx *ctx = (struct load_callback_ctx *)_ctx;
+ struct hostkeys *hostkeys = ctx->hostkeys;
+ struct hostkey_entry *tmp;
+
+ if (l->status == HKF_STATUS_INVALID) {
+ /* XXX make this verbose() in the future */
+ debug("%s:%ld: parse error in hostkeys file",
+ l->path, l->linenum);
+ return 0;
+ }
+
+ debug3("%s: found %skey type %s in file %s:%lu", __func__,
+ l->marker == MRK_NONE ? "" :
+ (l->marker == MRK_CA ? "ca " : "revoked "),
+ sshkey_type(l->key), l->path, l->linenum);
+ if ((tmp = recallocarray(hostkeys->entries, hostkeys->num_entries,
+ hostkeys->num_entries + 1, sizeof(*hostkeys->entries))) == NULL)
+ return SSH_ERR_ALLOC_FAIL;
+ hostkeys->entries = tmp;
+ hostkeys->entries[hostkeys->num_entries].host = xstrdup(ctx->host);
+ hostkeys->entries[hostkeys->num_entries].file = xstrdup(l->path);
+ hostkeys->entries[hostkeys->num_entries].line = l->linenum;
+ hostkeys->entries[hostkeys->num_entries].key = l->key;
+ l->key = NULL; /* steal it */
+ hostkeys->entries[hostkeys->num_entries].marker = l->marker;
+ hostkeys->num_entries++;
+ ctx->num_loaded++;
+
+ return 0;
+}
+
+void
+load_hostkeys(struct hostkeys *hostkeys, const char *host, const char *path)
+{
+ int r;
+ struct load_callback_ctx ctx;
+
+ ctx.host = host;
+ ctx.num_loaded = 0;
+ ctx.hostkeys = hostkeys;
+
+ 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));
+ }
+ if (ctx.num_loaded != 0)
+ debug3("%s: loaded %lu keys from %s", __func__,
+ ctx.num_loaded, host);
+}
+
+void
+free_hostkeys(struct hostkeys *hostkeys)
+{
+ u_int i;
+
+ for (i = 0; i < hostkeys->num_entries; i++) {
+ free(hostkeys->entries[i].host);
+ free(hostkeys->entries[i].file);
+ sshkey_free(hostkeys->entries[i].key);
+ explicit_bzero(hostkeys->entries + i, sizeof(*hostkeys->entries));
+ }
+ free(hostkeys->entries);
+ freezero(hostkeys, sizeof(*hostkeys));
+}
+
+static int
+check_key_not_revoked(struct hostkeys *hostkeys, struct sshkey *k)
+{
+ int is_cert = sshkey_is_cert(k);
+ u_int i;
+
+ for (i = 0; i < hostkeys->num_entries; i++) {
+ if (hostkeys->entries[i].marker != MRK_REVOKE)
+ continue;
+ if (sshkey_equal_public(k, hostkeys->entries[i].key))
+ return -1;
+ if (is_cert && k != NULL &&
+ sshkey_equal_public(k->cert->signature_key,
+ hostkeys->entries[i].key))
+ return -1;
+ }
+ return 0;
+}
+
+/*
+ * Match keys against a specified key, or look one up by key type.
+ *
+ * If looking for a keytype (key == NULL) and one is found then return
+ * HOST_FOUND, otherwise HOST_NEW.
+ *
+ * If looking for a key (key != NULL):
+ * 1. If the key is a cert and a matching CA is found, return HOST_OK
+ * 2. If the key is not a cert and a matching key is found, return HOST_OK
+ * 3. If no key matches but a key with a different type is found, then
+ * return HOST_CHANGED
+ * 4. If no matching keys are found, then return HOST_NEW.
+ *
+ * Finally, check any found key is not revoked.
+ */
+static HostStatus
+check_hostkeys_by_key_or_type(struct hostkeys *hostkeys,
+ struct sshkey *k, int keytype, const struct hostkey_entry **found)
+{
+ u_int i;
+ HostStatus end_return = HOST_NEW;
+ int want_cert = sshkey_is_cert(k);
+ HostkeyMarker want_marker = want_cert ? MRK_CA : MRK_NONE;
+
+ if (found != NULL)
+ *found = NULL;
+
+ for (i = 0; i < hostkeys->num_entries; i++) {
+ if (hostkeys->entries[i].marker != want_marker)
+ continue;
+ if (k == NULL) {
+ if (hostkeys->entries[i].key->type != keytype)
+ continue;
+ end_return = HOST_FOUND;
+ if (found != NULL)
+ *found = hostkeys->entries + i;
+ k = hostkeys->entries[i].key;
+ break;
+ }
+ if (want_cert) {
+ if (sshkey_equal_public(k->cert->signature_key,
+ hostkeys->entries[i].key)) {
+ /* A matching CA exists */
+ end_return = HOST_OK;
+ if (found != NULL)
+ *found = hostkeys->entries + i;
+ break;
+ }
+ } else {
+ if (sshkey_equal(k, hostkeys->entries[i].key)) {
+ end_return = HOST_OK;
+ if (found != NULL)
+ *found = hostkeys->entries + i;
+ break;
+ }
+ /* A non-maching key exists */
+ end_return = HOST_CHANGED;
+ if (found != NULL)
+ *found = hostkeys->entries + i;
+ }
+ }
+ if (check_key_not_revoked(hostkeys, k) != 0) {
+ end_return = HOST_REVOKED;
+ if (found != NULL)
+ *found = NULL;
+ }
+ return end_return;
+}
+
+HostStatus
+check_key_in_hostkeys(struct hostkeys *hostkeys, struct sshkey *key,
+ const struct hostkey_entry **found)
+{
+ if (key == NULL)
+ fatal("no key to look up");
+ return check_hostkeys_by_key_or_type(hostkeys, key, 0, found);
+}
+
+int
+lookup_key_in_hostkeys_by_type(struct hostkeys *hostkeys, int keytype,
+ const struct hostkey_entry **found)
+{
+ return (check_hostkeys_by_key_or_type(hostkeys, NULL, keytype,
+ found) == HOST_FOUND);
+}
+
+int
+lookup_marker_in_hostkeys(struct hostkeys *hostkeys, int want_marker)
+{
+ u_int i;
+
+ for (i = 0; i < hostkeys->num_entries; i++) {
+ if (hostkeys->entries[i].marker == (HostkeyMarker)want_marker)
+ return 1;
+ }
+ return 0;
+}
+
+static int
+write_host_entry(FILE *f, const char *host, const char *ip,
+ const struct sshkey *key, int store_hash)
+{
+ int r, success = 0;
+ char *hashed_host = NULL, *lhost;
+
+ lhost = xstrdup(host);
+ lowercase(lhost);
+
+ if (store_hash) {
+ if ((hashed_host = host_hash(lhost, NULL, 0)) == NULL) {
+ error("%s: host_hash failed", __func__);
+ free(lhost);
+ return 0;
+ }
+ fprintf(f, "%s ", hashed_host);
+ } else if (ip != NULL)
+ fprintf(f, "%s,%s ", lhost, ip);
+ else {
+ fprintf(f, "%s ", lhost);
+ }
+ free(lhost);
+ if ((r = sshkey_write(key, f)) == 0)
+ success = 1;
+ else
+ error("%s: sshkey_write failed: %s", __func__, ssh_err(r));
+ fputc('\n', f);
+ return success;
+}
+
+/*
+ * Create user ~/.ssh directory if it doesn't exist and we want to write to it.
+ * If notify is set, a message will be emitted if the directory is created.
+ */
+void
+hostfile_create_user_ssh_dir(const char *filename, int notify)
+{
+ char *dotsshdir = NULL, *p;
+ size_t len;
+ struct stat st;
+
+ if ((p = strrchr(filename, '/')) == NULL)
+ return;
+ len = p - filename;
+ dotsshdir = tilde_expand_filename("~/" _PATH_SSH_USER_DIR, getuid());
+ if (strlen(dotsshdir) > len || strncmp(filename, dotsshdir, len) != 0)
+ goto out; /* not ~/.ssh prefixed */
+ if (stat(dotsshdir, &st) == 0)
+ goto out; /* dir already exists */
+ else if (errno != ENOENT)
+ error("Could not stat %s: %s", dotsshdir, strerror(errno));
+ else {
+#ifdef WITH_SELINUX
+ ssh_selinux_setfscreatecon(dotsshdir);
+#endif
+ if (mkdir(dotsshdir, 0700) == -1)
+ error("Could not create directory '%.200s' (%s).",
+ dotsshdir, strerror(errno));
+ else if (notify)
+ logit("Created directory '%s'.", dotsshdir);
+#ifdef WITH_SELINUX
+ ssh_selinux_setfscreatecon(NULL);
+#endif
+ }
+ out:
+ free(dotsshdir);
+}
+
+/*
+ * Appends an entry to the host file. Returns false if the entry could not
+ * be appended.
+ */
+int
+add_host_to_hostfile(const char *filename, const char *host,
+ const struct sshkey *key, int store_hash)
+{
+ FILE *f;
+ int success;
+
+ if (key == NULL)
+ return 1; /* XXX ? */
+ hostfile_create_user_ssh_dir(filename, 0);
+ f = fopen(filename, "a");
+ if (!f)
+ return 0;
+ success = write_host_entry(f, host, NULL, key, store_hash);
+ fclose(f);
+ return success;
+}
+
+struct host_delete_ctx {
+ FILE *out;
+ int quiet;
+ const char *host;
+ 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_VERBOSE;
+ size_t i;
+
+ 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);
+ return 0;
+ }
+
+ /*
+ * If this line contains one of the keys that we will be
+ * adding later, then don't change it and mark the key for
+ * skipping.
+ */
+ for (i = 0; i < ctx->nkeys; i++) {
+ if (sshkey_equal(ctx->keys[i], l->key)) {
+ ctx->skip_keys[i] = 1;
+ fprintf(ctx->out, "%s\n", l->line);
+ debug3("%s: %s key already at %s:%ld", __func__,
+ sshkey_type(l->key), l->path, l->linenum);
+ return 0;
+ }
+ }
+
+ /*
+ * 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: Removed %s key for host %s",
+ ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "",
+ l->path, l->linenum, sshkey_type(l->key), ctx->host);
+ ctx->modified = 1;
+ return 0;
+ }
+ /* Retain non-matching hosts and invalid lines when deleting */
+ if (l->status == HKF_STATUS_INVALID) {
+ do_log2(loglevel, "%s%s%s:%ld: invalid known_hosts entry",
+ ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "",
+ l->path, l->linenum);
+ }
+ fprintf(ctx->out, "%s\n", l->line);
+ return 0;
+}
+
+int
+hostfile_replace_entries(const char *filename, const char *host, const char *ip,
+ struct sshkey **keys, size_t nkeys, int store_hash, int quiet, int hash_alg)
+{
+ int r, fd, oerrno = 0;
+ int loglevel = quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE;
+ struct host_delete_ctx ctx;
+ char *fp, *temp = NULL, *back = NULL;
+ mode_t omask;
+ size_t i;
+
+ omask = umask(077);
+
+ memset(&ctx, 0, sizeof(ctx));
+ ctx.host = host;
+ ctx.quiet = quiet;
+ if ((ctx.skip_keys = calloc(nkeys, sizeof(*ctx.skip_keys))) == NULL)
+ return SSH_ERR_ALLOC_FAIL;
+ ctx.keys = keys;
+ ctx.nkeys = nkeys;
+ ctx.modified = 0;
+
+ /*
+ * Prepare temporary file for in-place deletion.
+ */
+ if ((r = asprintf(&temp, "%s.XXXXXXXXXXX", filename)) == -1 ||
+ (r = asprintf(&back, "%s.old", filename)) == -1) {
+ r = SSH_ERR_ALLOC_FAIL;
+ goto fail;
+ }
+
+ if ((fd = mkstemp(temp)) == -1) {
+ oerrno = errno;
+ error("%s: mkstemp: %s", __func__, strerror(oerrno));
+ r = SSH_ERR_SYSTEM_ERROR;
+ goto fail;
+ }
+ if ((ctx.out = fdopen(fd, "w")) == NULL) {
+ oerrno = errno;
+ close(fd);
+ error("%s: fdopen: %s", __func__, strerror(oerrno));
+ r = SSH_ERR_SYSTEM_ERROR;
+ goto fail;
+ }
+
+ /* Remove all entries for the specified host from the file */
+ if ((r = hostkeys_foreach(filename, host_delete, &ctx, host, ip,
+ HKF_WANT_PARSE_KEY)) != 0) {
+ oerrno = errno;
+ error("%s: hostkeys_foreach failed: %s", __func__, ssh_err(r));
+ goto fail;
+ }
+
+ /* Add the requested keys */
+ for (i = 0; i < nkeys; i++) {
+ if (ctx.skip_keys[i])
+ continue;
+ 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;
+
+ 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:
+ if (temp != NULL && r != 0)
+ unlink(temp);
+ free(temp);
+ free(back);
+ if (ctx.out != NULL)
+ fclose(ctx.out);
+ free(ctx.skip_keys);
+ umask(omask);
+ if (r == SSH_ERR_SYSTEM_ERROR)
+ errno = oerrno;
+ return r;
+}
+
+static int
+match_maybe_hashed(const char *host, const char *names, int *was_hashed)
+{
+ int hashed = *names == HASH_DELIM;
+ const char *hashed_host;
+ size_t nlen = strlen(names);
+
+ if (was_hashed != NULL)
+ *was_hashed = hashed;
+ if (hashed) {
+ if ((hashed_host = host_hash(host, names, nlen)) == NULL)
+ return -1;
+ return nlen == strlen(hashed_host) &&
+ strncmp(hashed_host, names, nlen) == 0;
+ }
+ return match_hostname(host, names) == 1;
+}
+
+int
+hostkeys_foreach(const char *path, hostkeys_foreach_fn *callback, void *ctx,
+ const char *host, const char *ip, u_int options)
+{
+ FILE *f;
+ char *line = NULL, 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 linesize = 0, l;
+
+ memset(&lineinfo, 0, sizeof(lineinfo));
+ if (host == NULL && (options & HKF_WANT_MATCH) != 0)
+ return SSH_ERR_INVALID_ARGUMENT;
+ if ((f = fopen(path, "r")) == NULL)
+ return SSH_ERR_SYSTEM_ERROR;
+
+ debug3("%s: reading file \"%s\"", __func__, path);
+ while (getline(&line, &linesize, f) != -1) {
+ linenum++;
+ line[strcspn(line, "\n")] = '\0';
+
+ free(lineinfo.line);
+ sshkey_free(lineinfo.key);
+ memset(&lineinfo, 0, sizeof(lineinfo));
+ lineinfo.path = path;
+ lineinfo.linenum = linenum;
+ lineinfo.line = xstrdup(line);
+ 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) == 0) {
+ lineinfo.status = HKF_STATUS_COMMENT;
+ if ((r = callback(&lineinfo, ctx)) != 0)
+ break;
+ }
+ continue;
+ }
+
+ if ((lineinfo.marker = check_markers(&cp)) == MRK_ERROR) {
+ verbose("%s: invalid marker at %s:%lu",
+ __func__, path, linenum);
+ if ((options & HKF_WANT_MATCH) == 0)
+ goto bad;
+ continue;
+ }
+
+ /* Find the end of the host name portion. */
+ for (cp2 = cp; *cp2 && *cp2 != ' ' && *cp2 != '\t'; cp2++)
+ ;
+ lineinfo.hosts = cp;
+ *cp2++ = '\0';
+
+ /* Check if the host name matches. */
+ if (host != NULL) {
+ 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 type",
+ path, linenum);
+ goto bad;
+ }
+ lineinfo.rawkey = cp = cp2;
+
+ if ((options & HKF_WANT_PARSE_KEY) != 0) {
+ /*
+ * Extract the key from the line. This will skip
+ * any leading whitespace. Ignore badly formatted
+ * lines.
+ */
+ if ((lineinfo.key = sshkey_new(KEY_UNSPEC)) == NULL) {
+ error("%s: sshkey_new failed", __func__);
+ r = SSH_ERR_ALLOC_FAIL;
+ break;
+ }
+ if (!hostfile_read_key(&cp, &kbits, lineinfo.key)) {
+ goto bad;
+ }
+ 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);
+
+ /*
+ * Assume legacy RSA1 if the first component is a short
+ * decimal number.
+ */
+ if (lineinfo.keytype == KEY_UNSPEC && l < 8 &&
+ strspn(ktype, "0123456789") == l)
+ goto bad;
+
+ /*
+ * 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;
+ continue;
+ }
+ }
+ if ((r = callback(&lineinfo, ctx)) != 0)
+ break;
+ }
+ sshkey_free(lineinfo.key);
+ free(lineinfo.line);
+ free(line);
+ fclose(f);
+ return r;
+}