diff options
Diffstat (limited to 'src/known_hosts.c')
-rw-r--r-- | src/known_hosts.c | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/src/known_hosts.c b/src/known_hosts.c index ded36a90..2d90a41d 100644 --- a/src/known_hosts.c +++ b/src/known_hosts.c @@ -647,6 +647,83 @@ int ssh_write_knownhost(ssh_session session) { return 0; } +/** + * @brief Check which kind of host keys should be preferred for connection + * by reading the known_hosts file. + * + * @param[in] session The SSH session to use. + * + * @returns Bitfield of supported SSH hostkey algorithms + * SSH_ERROR on error + */ +int ssh_knownhosts_algorithms(ssh_session session) { + FILE *file = NULL; + char **tokens; + char *host; + char *hostport; + const char *type; + int match; + int ret = 0; + + if (session->opts.knownhosts == NULL) { + if (ssh_options_apply(session) < 0) { + ssh_set_error(session, SSH_REQUEST_DENIED, + "Can't find a known_hosts file"); + return SSH_ERROR; + } + } + + if (session->opts.host == NULL) { + return 0; + } + + host = ssh_lowercase(session->opts.host); + hostport = ssh_hostport(host, session->opts.port); + if (host == NULL || hostport == NULL) { + ssh_set_error_oom(session); + SAFE_FREE(host); + SAFE_FREE(hostport); + + return SSH_ERROR; + } + + do { + tokens = ssh_get_knownhost_line(&file, + session->opts.knownhosts, &type); + + /* End of file, return the current state */ + if (tokens == NULL) { + break; + } + match = match_hashed_host(host, tokens[0]); + if (match == 0){ + match = match_hostname(hostport, tokens[0], strlen(tokens[0])); + } + if (match == 0) { + match = match_hostname(host, tokens[0], strlen(tokens[0])); + } + if (match == 0) { + match = match_hashed_host(hostport, tokens[0]); + } + if (match) { + /* We got a match. Now check the key type */ + SSH_LOG(SSH_LOG_DEBUG, "server %s:%d has %s in known_hosts", + host, session->opts.port, type); + ret |= 1 << ssh_key_type_from_name(type); + } + tokens_free(tokens); + } while (1); + + SAFE_FREE(host); + SAFE_FREE(hostport); + if (file != NULL) { + fclose(file); + } + + /* Return the current state at end of file */ + return ret; +} + /** @} */ /* vim: set ts=4 sw=4 et cindent: */ |