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Damien Millerd4a8b7e1999-10-27 13:42:43 +10001/*
Damien Miller95def091999-11-25 00:26:21 +11002 * Author: Tatu Ylonen <ylo@cs.hut.fi>
Damien Miller95def091999-11-25 00:26:21 +11003 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4 * All rights reserved
Damien Miller95def091999-11-25 00:26:21 +11005 * Rhosts or /etc/hosts.equiv authentication combined with RSA host
6 * authentication.
7 *
Damien Millere4340be2000-09-16 13:29:08 +11008 * As far as I am concerned, the code I have written for this software
9 * can be used freely for any purpose. Any derived versions of this
10 * software must be clearly marked as such, and if the derived work is
11 * incompatible with the protocol description in the RFC file, it must be
12 * called by a name other than "ssh" or "Secure Shell".
Damien Miller95def091999-11-25 00:26:21 +110013 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100014
15#include "includes.h"
Ben Lindstroma4789ef2001-06-25 04:40:49 +000016RCSID("$OpenBSD: auth-rh-rsa.c,v 1.25 2001/06/23 03:04:42 markus Exp $");
Damien Millerd4a8b7e1999-10-27 13:42:43 +100017
18#include "packet.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100019#include "xmalloc.h"
20#include "uidswap.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000021#include "log.h"
Damien Miller32265091999-11-12 11:33:04 +110022#include "servconf.h"
Damien Miller450a7a12000-03-26 13:04:51 +100023#include "key.h"
24#include "hostfile.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000025#include "pathnames.h"
26#include "auth.h"
27#include "tildexpand.h"
28#include "canohost.h"
Damien Miller450a7a12000-03-26 13:04:51 +100029
Damien Miller5428f641999-11-25 11:54:57 +110030/*
31 * Tries to authenticate the user using the .rhosts file and the host using
32 * its host key. Returns true if authentication succeeds.
33 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100034
Damien Miller4af51302000-04-16 11:18:38 +100035int
Damien Miller450a7a12000-03-26 13:04:51 +100036auth_rhosts_rsa(struct passwd *pw, const char *client_user, RSA *client_host_key)
Damien Millerd4a8b7e1999-10-27 13:42:43 +100037{
Damien Miller95def091999-11-25 00:26:21 +110038 extern ServerOptions options;
39 const char *canonical_hostname;
40 HostStatus host_status;
Ben Lindstrom83647ce2001-06-25 04:30:16 +000041 Key *client_key;
Damien Millerd4a8b7e1999-10-27 13:42:43 +100042
Damien Miller874d77b2000-10-14 16:23:11 +110043 debug("Trying rhosts with RSA host authentication for client user %.100s", client_user);
Damien Millerd4a8b7e1999-10-27 13:42:43 +100044
Damien Miller874d77b2000-10-14 16:23:11 +110045 if (pw == NULL || client_host_key == NULL)
Damien Miller450a7a12000-03-26 13:04:51 +100046 return 0;
47
Damien Miller95def091999-11-25 00:26:21 +110048 /* Check if we would accept it using rhosts authentication. */
49 if (!auth_rhosts(pw, client_user))
50 return 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +100051
Damien Miller33804262001-02-04 23:20:18 +110052 canonical_hostname = get_canonical_hostname(
53 options.reverse_mapping_check);
Damien Millerd4a8b7e1999-10-27 13:42:43 +100054
Damien Miller450a7a12000-03-26 13:04:51 +100055 debug("Rhosts RSA authentication: canonical host %.900s", canonical_hostname);
56
57 /* wrap the RSA key into a 'generic' key */
Damien Miller0bc1bd82000-11-13 22:57:25 +110058 client_key = key_new(KEY_RSA1);
Damien Miller450a7a12000-03-26 13:04:51 +100059 BN_copy(client_key->rsa->e, client_host_key->e);
60 BN_copy(client_key->rsa->n, client_host_key->n);
Damien Miller32265091999-11-12 11:33:04 +110061
Ben Lindstrom83647ce2001-06-25 04:30:16 +000062 host_status = check_key_in_hostfiles(pw, client_key, canonical_hostname,
63 _PATH_SSH_SYSTEM_HOSTFILE,
Ben Lindstroma4789ef2001-06-25 04:40:49 +000064 options.ignore_user_known_hosts ? NULL : _PATH_SSH_USER_HOSTFILE);
Damien Miller33e511e1999-11-11 11:43:13 +110065
Damien Miller450a7a12000-03-26 13:04:51 +100066 key_free(client_key);
Damien Millerd4a8b7e1999-10-27 13:42:43 +100067
Damien Miller95def091999-11-25 00:26:21 +110068 if (host_status != HOST_OK) {
69 debug("Rhosts with RSA host authentication denied: unknown or invalid host key");
70 packet_send_debug("Your host key cannot be verified: unknown or invalid host key.");
71 return 0;
72 }
73 /* A matching host key was found and is known. */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100074
Damien Miller95def091999-11-25 00:26:21 +110075 /* Perform the challenge-response dialog with the client for the host key. */
Damien Miller450a7a12000-03-26 13:04:51 +100076 if (!auth_rsa_challenge_dialog(client_host_key)) {
Damien Miller95def091999-11-25 00:26:21 +110077 log("Client on %.800s failed to respond correctly to host authentication.",
78 canonical_hostname);
79 return 0;
80 }
Damien Miller5428f641999-11-25 11:54:57 +110081 /*
82 * We have authenticated the user using .rhosts or /etc/hosts.equiv,
83 * and the host using RSA. We accept the authentication.
84 */
Damien Miller95def091999-11-25 00:26:21 +110085
86 verbose("Rhosts with RSA host authentication accepted for %.100s, %.100s on %.700s.",
Damien Miller450a7a12000-03-26 13:04:51 +100087 pw->pw_name, client_user, canonical_hostname);
Damien Miller95def091999-11-25 00:26:21 +110088 packet_send_debug("Rhosts with RSA host authentication accepted.");
89 return 1;
Damien Millerd4a8b7e1999-10-27 13:42:43 +100090}