Put ssh back into the repository
Change-Id: I23324372188fa6ed3f93a32b84365f5df6367590
diff --git a/hostfile.c b/hostfile.c
new file mode 100644
index 0000000..b6f924b
--- /dev/null
+++ b/hostfile.c
@@ -0,0 +1,488 @@
+/* $OpenBSD: hostfile.c,v 1.50 2010/12/04 13:31:37 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 <netinet/in.h>
+
+#include <openssl/hmac.h>
+#include <openssl/sha.h>
+
+#include <resolv.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "xmalloc.h"
+#include "match.h"
+#include "key.h"
+#include "hostfile.h"
+#include "log.h"
+#include "misc.h"
+
+struct hostkeys {
+ struct hostkey_entry *entries;
+ u_int num_entries;
+};
+
+static int
+extract_salt(const char *s, u_int l, 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);
+ xfree(b64salt);
+ if (ret == -1) {
+ debug2("extract_salt: salt decode error");
+ return (-1);
+ }
+ if (ret != SHA_DIGEST_LENGTH) {
+ debug2("extract_salt: expected salt len %d, got %d",
+ SHA_DIGEST_LENGTH, ret);
+ return (-1);
+ }
+
+ return (0);
+}
+
+char *
+host_hash(const char *host, const char *name_from_hostfile, u_int src_len)
+{
+ const EVP_MD *md = EVP_sha1();
+ HMAC_CTX mac_ctx;
+ char salt[256], result[256], uu_salt[512], uu_result[512];
+ static char encoded[1024];
+ u_int i, len;
+
+ len = EVP_MD_size(md);
+
+ if (name_from_hostfile == NULL) {
+ /* Create new salt */
+ for (i = 0; i < len; i++)
+ salt[i] = arc4random();
+ } else {
+ /* Extract salt from known host entry */
+ if (extract_salt(name_from_hostfile, src_len, salt,
+ sizeof(salt)) == -1)
+ return (NULL);
+ }
+
+ HMAC_Init(&mac_ctx, salt, len, md);
+ HMAC_Update(&mac_ctx, host, strlen(host));
+ HMAC_Final(&mac_ctx, result, NULL);
+ HMAC_cleanup(&mac_ctx);
+
+ if (__b64_ntop(salt, len, uu_salt, sizeof(uu_salt)) == -1 ||
+ __b64_ntop(result, len, uu_result, sizeof(uu_result)) == -1)
+ fatal("host_hash: __b64_ntop failed");
+
+ 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, Key *ret)
+{
+ char *cp;
+
+ /* Skip leading whitespace. */
+ for (cp = *cpp; *cp == ' ' || *cp == '\t'; cp++)
+ ;
+
+ if (key_read(ret, &cp) != 1)
+ return 0;
+
+ /* Skip trailing whitespace. */
+ for (; *cp == ' ' || *cp == '\t'; cp++)
+ ;
+
+ /* Return results. */
+ *cpp = cp;
+ if (bitsp != NULL)
+ *bitsp = key_size(ret);
+ return 1;
+}
+
+static int
+hostfile_check_key(int bits, const Key *key, const char *host,
+ const char *filename, u_long linenum)
+{
+ 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);
+ }
+ 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;
+}
+
+void
+load_hostkeys(struct hostkeys *hostkeys, const char *host, const char *path)
+{
+ FILE *f;
+ char line[8192];
+ u_long linenum = 0, num_loaded = 0;
+ char *cp, *cp2, *hashed_host;
+ HostkeyMarker marker;
+ Key *key;
+ int kbits;
+
+ if ((f = fopen(path, "r")) == NULL)
+ return;
+ debug3("%s: loading entries for host \"%.100s\" from file \"%s\"",
+ __func__, host, path);
+ while (read_keyfile_line(f, path, line, sizeof(line), &linenum) == 0) {
+ cp = line;
+
+ /* Skip any leading whitespace, comments and empty lines. */
+ for (; *cp == ' ' || *cp == '\t'; cp++)
+ ;
+ if (!*cp || *cp == '#' || *cp == '\n')
+ continue;
+
+ if ((marker = check_markers(&cp)) == MRK_ERROR) {
+ verbose("%s: invalid marker at %s:%lu",
+ __func__, path, linenum);
+ continue;
+ }
+
+ /* Find the end of the host name portion. */
+ for (cp2 = cp; *cp2 && *cp2 != ' ' && *cp2 != '\t'; cp2++)
+ ;
+
+ /* Check if the host name matches. */
+ if (match_hostname(host, cp, (u_int) (cp2 - cp)) != 1) {
+ if (*cp != HASH_DELIM)
+ continue;
+ hashed_host = host_hash(host, cp, (u_int) (cp2 - cp));
+ if (hashed_host == NULL) {
+ debug("Invalid hashed host line %lu of %s",
+ linenum, path);
+ continue;
+ }
+ if (strncmp(hashed_host, cp, (u_int) (cp2 - cp)) != 0)
+ continue;
+ }
+
+ /* Got a match. Skip host name. */
+ cp = cp2;
+
+ /*
+ * Extract the key from the line. This will skip any leading
+ * whitespace. Ignore badly formatted lines.
+ */
+ key = key_new(KEY_UNSPEC);
+ if (!hostfile_read_key(&cp, &kbits, key)) {
+ key_free(key);
+ key = key_new(KEY_RSA1);
+ if (!hostfile_read_key(&cp, &kbits, key)) {
+ key_free(key);
+ continue;
+ }
+ }
+ if (!hostfile_check_key(kbits, key, host, path, linenum))
+ continue;
+
+ debug3("%s: found %skey type %s in file %s:%lu", __func__,
+ marker == MRK_NONE ? "" :
+ (marker == MRK_CA ? "ca " : "revoked "),
+ key_type(key), path, linenum);
+ hostkeys->entries = xrealloc(hostkeys->entries,
+ hostkeys->num_entries + 1, sizeof(*hostkeys->entries));
+ hostkeys->entries[hostkeys->num_entries].host = xstrdup(host);
+ hostkeys->entries[hostkeys->num_entries].file = xstrdup(path);
+ hostkeys->entries[hostkeys->num_entries].line = linenum;
+ hostkeys->entries[hostkeys->num_entries].key = key;
+ hostkeys->entries[hostkeys->num_entries].marker = marker;
+ hostkeys->num_entries++;
+ num_loaded++;
+ }
+ debug3("%s: loaded %lu keys", __func__, num_loaded);
+ fclose(f);
+ return;
+}
+
+void
+free_hostkeys(struct hostkeys *hostkeys)
+{
+ u_int i;
+
+ for (i = 0; i < hostkeys->num_entries; i++) {
+ xfree(hostkeys->entries[i].host);
+ xfree(hostkeys->entries[i].file);
+ key_free(hostkeys->entries[i].key);
+ bzero(hostkeys->entries + i, sizeof(*hostkeys->entries));
+ }
+ if (hostkeys->entries != NULL)
+ xfree(hostkeys->entries);
+ hostkeys->entries = NULL;
+ hostkeys->num_entries = 0;
+ xfree(hostkeys);
+}
+
+static int
+check_key_not_revoked(struct hostkeys *hostkeys, Key *k)
+{
+ int is_cert = key_is_cert(k);
+ u_int i;
+
+ for (i = 0; i < hostkeys->num_entries; i++) {
+ if (hostkeys->entries[i].marker != MRK_REVOKE)
+ continue;
+ if (key_equal_public(k, hostkeys->entries[i].key))
+ return -1;
+ if (is_cert &&
+ key_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,
+ Key *k, int keytype, const struct hostkey_entry **found)
+{
+ u_int i;
+ HostStatus end_return = HOST_NEW;
+ int want_cert = key_is_cert(k);
+ HostkeyMarker want_marker = want_cert ? MRK_CA : MRK_NONE;
+ int proto = (k ? k->type : keytype) == KEY_RSA1 ? 1 : 2;
+
+ if (found != NULL)
+ *found = NULL;
+
+ for (i = 0; i < hostkeys->num_entries; i++) {
+ if (proto == 1 && hostkeys->entries[i].key->type != KEY_RSA1)
+ continue;
+ if (proto == 2 && hostkeys->entries[i].key->type == KEY_RSA1)
+ continue;
+ 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 (key_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 (key_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, Key *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);
+}
+
+/*
+ * 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 Key *key,
+ int store_hash)
+{
+ FILE *f;
+ int success = 0;
+ char *hashed_host = NULL;
+
+ if (key == NULL)
+ return 1; /* XXX ? */
+ f = fopen(filename, "a");
+ if (!f)
+ return 0;
+
+ if (store_hash) {
+ if ((hashed_host = host_hash(host, NULL, 0)) == NULL) {
+ error("add_host_to_hostfile: host_hash failed");
+ fclose(f);
+ return 0;
+ }
+ }
+ fprintf(f, "%s ", store_hash ? hashed_host : host);
+
+ if (key_write(key, f)) {
+ success = 1;
+ } else {
+ error("add_host_to_hostfile: saving key in %s failed", filename);
+ }
+ fprintf(f, "\n");
+ fclose(f);
+ return success;
+}