| /* |
| |
| auth-rh-rsa.c |
| |
| Author: Tatu Ylonen <ylo@cs.hut.fi> |
| |
| Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland |
| All rights reserved |
| |
| Created: Sun May 7 03:08:06 1995 ylo |
| |
| Rhosts or /etc/hosts.equiv authentication combined with RSA host |
| authentication. |
| |
| */ |
| |
| #include "includes.h" |
| RCSID("$Id: auth-rh-rsa.c,v 1.3 1999/11/12 00:33:04 damien Exp $"); |
| |
| #include "packet.h" |
| #include "ssh.h" |
| #include "xmalloc.h" |
| #include "uidswap.h" |
| #include "servconf.h" |
| |
| /* Tries to authenticate the user using the .rhosts file and the host using |
| its host key. Returns true if authentication succeeds. */ |
| |
| int auth_rhosts_rsa(struct passwd *pw, const char *client_user, |
| unsigned int client_host_key_bits, |
| BIGNUM *client_host_key_e, BIGNUM *client_host_key_n) |
| { |
| extern ServerOptions options; |
| const char *canonical_hostname; |
| HostStatus host_status; |
| BIGNUM *ke, *kn; |
| |
| debug("Trying rhosts with RSA host authentication for %.100s", client_user); |
| |
| /* Check if we would accept it using rhosts authentication. */ |
| if (!auth_rhosts(pw, client_user, options.ignore_rhosts, options.strict_modes)) |
| return 0; |
| |
| canonical_hostname = get_canonical_hostname(); |
| |
| debug("Rhosts RSA authentication: canonical host %.900s", |
| canonical_hostname); |
| |
| /* Check if we know the host and its host key. */ |
| /* Check system-wide host file. */ |
| ke = BN_new(); |
| kn = BN_new(); |
| host_status = check_host_in_hostfile(SSH_SYSTEM_HOSTFILE, canonical_hostname, |
| client_host_key_bits, client_host_key_e, |
| client_host_key_n, ke, kn); |
| |
| /* Check user host file unless ignored. */ |
| if (host_status != HOST_OK && !options.ignore_user_known_hosts) { |
| struct stat st; |
| char *user_hostfile = tilde_expand_filename(SSH_USER_HOSTFILE, pw->pw_uid); |
| /* Check file permissions of SSH_USER_HOSTFILE, |
| auth_rsa() did already check pw->pw_dir, but there is a race XXX */ |
| if (options.strict_modes && |
| (stat(user_hostfile, &st) == 0) && |
| ((st.st_uid != 0 && st.st_uid != pw->pw_uid) || |
| (st.st_mode & 022) != 0)) { |
| log("Rhosts RSA authentication refused for %.100s: bad owner or modes for %.200s", |
| pw->pw_name, user_hostfile); |
| } else { |
| /* XXX race between stat and the following open() */ |
| temporarily_use_uid(pw->pw_uid); |
| host_status = check_host_in_hostfile(user_hostfile, canonical_hostname, |
| client_host_key_bits, client_host_key_e, |
| client_host_key_n, ke, kn); |
| restore_uid(); |
| } |
| xfree(user_hostfile); |
| } |
| BN_free(ke); |
| BN_free(kn); |
| |
| if (host_status != HOST_OK) { |
| /* The host key was not found. */ |
| debug("Rhosts with RSA host authentication denied: unknown or invalid host key"); |
| packet_send_debug("Your host key cannot be verified: unknown or invalid host key."); |
| return 0; |
| } |
| |
| /* A matching host key was found and is known. */ |
| |
| /* Perform the challenge-response dialog with the client for the host key. */ |
| if (!auth_rsa_challenge_dialog(client_host_key_bits, |
| client_host_key_e, client_host_key_n)) |
| { |
| log("Client on %.800s failed to respond correctly to host authentication.", |
| canonical_hostname); |
| return 0; |
| } |
| |
| /* We have authenticated the user using .rhosts or /etc/hosts.equiv, and |
| the host using RSA. We accept the authentication. */ |
| |
| log("Rhosts with RSA host authentication accepted for %.100s, %.100s on %.700s.", |
| pw->pw_name, client_user, canonical_hostname); |
| packet_send_debug("Rhosts with RSA host authentication accepted."); |
| return 1; |
| } |