5 * Author: Tatu Ylonen <ylo@cs.hut.fi>
7 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
10 * Created: Sun May 7 03:08:06 1995 ylo
12 * Rhosts or /etc/hosts.equiv authentication combined with RSA host
27 * Tries to authenticate the user using the .rhosts file and the host using
28 * its host key. Returns true if authentication succeeds.
32 auth_rhosts_rsa(struct passwd *pw, const char *client_user,
33 BIGNUM *client_host_key_e, BIGNUM *client_host_key_n)
35 extern ServerOptions options;
36 const char *canonical_hostname;
37 HostStatus host_status;
40 debug("Trying rhosts with RSA host authentication for %.100s", client_user);
42 /* Check if we would accept it using rhosts authentication. */
43 if (!auth_rhosts(pw, client_user))
46 canonical_hostname = get_canonical_hostname();
48 debug("Rhosts RSA authentication: canonical host %.900s",
51 /* Check if we know the host and its host key. */
54 host_status = check_host_in_hostfile(SSH_SYSTEM_HOSTFILE, canonical_hostname,
55 client_host_key_e, client_host_key_n,
58 /* Check user host file unless ignored. */
59 if (host_status != HOST_OK && !options.ignore_user_known_hosts) {
61 char *user_hostfile = tilde_expand_filename(SSH_USER_HOSTFILE, pw->pw_uid);
63 * Check file permissions of SSH_USER_HOSTFILE, auth_rsa()
64 * did already check pw->pw_dir, but there is a race XXX
66 if (options.strict_modes &&
67 (stat(user_hostfile, &st) == 0) &&
68 ((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
69 (st.st_mode & 022) != 0)) {
70 log("Rhosts RSA authentication refused for %.100s: bad owner or modes for %.200s",
71 pw->pw_name, user_hostfile);
73 /* XXX race between stat and the following open() */
74 temporarily_use_uid(pw->pw_uid);
75 host_status = check_host_in_hostfile(user_hostfile, canonical_hostname,
76 client_host_key_e, client_host_key_n,
85 if (host_status != HOST_OK) {
86 debug("Rhosts with RSA host authentication denied: unknown or invalid host key");
87 packet_send_debug("Your host key cannot be verified: unknown or invalid host key.");
90 /* A matching host key was found and is known. */
92 /* Perform the challenge-response dialog with the client for the host key. */
93 if (!auth_rsa_challenge_dialog(client_host_key_e, client_host_key_n)) {
94 log("Client on %.800s failed to respond correctly to host authentication.",
99 * We have authenticated the user using .rhosts or /etc/hosts.equiv,
100 * and the host using RSA. We accept the authentication.
103 verbose("Rhosts with RSA host authentication accepted for %.100s, %.100s on %.700s.",
104 pw->pw_name, client_user, canonical_hostname);
105 packet_send_debug("Rhosts with RSA host authentication accepted.");