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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 Lindstrom5facb2b2002-03-26 03:08:47 +000016RCSID("$OpenBSD: auth-rh-rsa.c,v 1.34 2002/03/25 09:25:06 markus Exp $");
Damien Millerd4a8b7e1999-10-27 13:42:43 +100017
18#include "packet.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100019#include "uidswap.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000020#include "log.h"
Damien Miller32265091999-11-12 11:33:04 +110021#include "servconf.h"
Damien Miller450a7a12000-03-26 13:04:51 +100022#include "key.h"
23#include "hostfile.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000024#include "pathnames.h"
25#include "auth.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000026#include "canohost.h"
Damien Miller450a7a12000-03-26 13:04:51 +100027
Ben Lindstrom7a2073c2002-03-22 02:30:41 +000028#include "monitor_wrap.h"
29
Ben Lindstrom186b7da2002-03-22 01:20:32 +000030/* import */
31extern ServerOptions options;
32
Damien Miller4af51302000-04-16 11:18:38 +100033int
Ben Lindstrom186b7da2002-03-22 01:20:32 +000034auth_rhosts_rsa_key_allowed(struct passwd *pw, char *cuser, char *chost,
35 Key *client_host_key)
Damien Millerd4a8b7e1999-10-27 13:42:43 +100036{
Damien Miller95def091999-11-25 00:26:21 +110037 HostStatus host_status;
Damien Millerd4a8b7e1999-10-27 13:42:43 +100038
Damien Miller95def091999-11-25 00:26:21 +110039 /* Check if we would accept it using rhosts authentication. */
Ben Lindstrom186b7da2002-03-22 01:20:32 +000040 if (!auth_rhosts(pw, cuser))
Damien Miller95def091999-11-25 00:26:21 +110041 return 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +100042
Damien Millerd221ca62002-01-22 23:11:00 +110043 host_status = check_key_in_hostfiles(pw, client_host_key,
Ben Lindstrom186b7da2002-03-22 01:20:32 +000044 chost, _PATH_SSH_SYSTEM_HOSTFILE,
Ben Lindstroma4789ef2001-06-25 04:40:49 +000045 options.ignore_user_known_hosts ? NULL : _PATH_SSH_USER_HOSTFILE);
Damien Miller33e511e1999-11-11 11:43:13 +110046
Ben Lindstrom6328ab32002-03-22 02:54:23 +000047 return (host_status == HOST_OK);
Ben Lindstrom186b7da2002-03-22 01:20:32 +000048}
49
50/*
51 * Tries to authenticate the user using the .rhosts file and the host using
52 * its host key. Returns true if authentication succeeds.
53 */
54int
55auth_rhosts_rsa(struct passwd *pw, char *cuser, Key *client_host_key)
56{
57 char *chost;
58
59 debug("Trying rhosts with RSA host authentication for client user %.100s",
60 cuser);
61
62 if (pw == NULL || client_host_key == NULL ||
63 client_host_key->rsa == NULL)
64 return 0;
65
66 chost = (char *)get_canonical_hostname(options.verify_reverse_mapping);
67 debug("Rhosts RSA authentication: canonical host %.900s", chost);
68
Ben Lindstrom7a2073c2002-03-22 02:30:41 +000069 if (!PRIVSEP(auth_rhosts_rsa_key_allowed(pw, cuser, chost, client_host_key))) {
Damien Miller95def091999-11-25 00:26:21 +110070 debug("Rhosts with RSA host authentication denied: unknown or invalid host key");
71 packet_send_debug("Your host key cannot be verified: unknown or invalid host key.");
72 return 0;
73 }
74 /* A matching host key was found and is known. */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100075
Damien Miller95def091999-11-25 00:26:21 +110076 /* Perform the challenge-response dialog with the client for the host key. */
Ben Lindstrom9c8aefe2002-03-22 01:12:58 +000077 if (!auth_rsa_challenge_dialog(client_host_key)) {
Damien Miller95def091999-11-25 00:26:21 +110078 log("Client on %.800s failed to respond correctly to host authentication.",
Ben Lindstrom186b7da2002-03-22 01:20:32 +000079 chost);
Damien Miller95def091999-11-25 00:26:21 +110080 return 0;
81 }
Damien Miller5428f641999-11-25 11:54:57 +110082 /*
83 * We have authenticated the user using .rhosts or /etc/hosts.equiv,
84 * and the host using RSA. We accept the authentication.
85 */
Damien Miller95def091999-11-25 00:26:21 +110086
87 verbose("Rhosts with RSA host authentication accepted for %.100s, %.100s on %.700s.",
Ben Lindstrom186b7da2002-03-22 01:20:32 +000088 pw->pw_name, cuser, chost);
Damien Miller95def091999-11-25 00:26:21 +110089 packet_send_debug("Rhosts with RSA host authentication accepted.");
90 return 1;
Damien Millerd4a8b7e1999-10-27 13:42:43 +100091}