blob: 506a5a2398156bebd0a75fb5c75e7c7a39a96f62 [file] [log] [blame]
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 Lindstrom3fcf1a22001-04-08 18:26:59 +000016RCSID("$OpenBSD: auth-rh-rsa.c,v 1.23 2001/04/06 21:00:04 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;
Damien Miller450a7a12000-03-26 13:04:51 +100041 Key *client_key, *found;
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 Miller0bc1bd82000-11-13 22:57:25 +110061 found = key_new(KEY_RSA1);
Damien Miller32265091999-11-12 11:33:04 +110062
Damien Miller95def091999-11-25 00:26:21 +110063 /* Check if we know the host and its host key. */
Ben Lindstrom226cfa02001-01-22 05:34:40 +000064 host_status = check_host_in_hostfile(_PATH_SSH_SYSTEM_HOSTFILE, canonical_hostname,
Ben Lindstrom46c16222000-12-22 01:43:59 +000065 client_key, found, NULL);
Damien Miller33e511e1999-11-11 11:43:13 +110066
Damien Miller95def091999-11-25 00:26:21 +110067 /* Check user host file unless ignored. */
68 if (host_status != HOST_OK && !options.ignore_user_known_hosts) {
69 struct stat st;
Ben Lindstrom226cfa02001-01-22 05:34:40 +000070 char *user_hostfile = tilde_expand_filename(_PATH_SSH_USER_HOSTFILE, pw->pw_uid);
Damien Miller5428f641999-11-25 11:54:57 +110071 /*
Ben Lindstrom226cfa02001-01-22 05:34:40 +000072 * Check file permissions of _PATH_SSH_USER_HOSTFILE, auth_rsa()
Damien Miller5428f641999-11-25 11:54:57 +110073 * did already check pw->pw_dir, but there is a race XXX
74 */
Damien Miller95def091999-11-25 00:26:21 +110075 if (options.strict_modes &&
76 (stat(user_hostfile, &st) == 0) &&
77 ((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
78 (st.st_mode & 022) != 0)) {
79 log("Rhosts RSA authentication refused for %.100s: bad owner or modes for %.200s",
80 pw->pw_name, user_hostfile);
81 } else {
82 /* XXX race between stat and the following open() */
Ben Lindstrom3fcf1a22001-04-08 18:26:59 +000083 temporarily_use_uid(pw);
Damien Miller95def091999-11-25 00:26:21 +110084 host_status = check_host_in_hostfile(user_hostfile, canonical_hostname,
Ben Lindstrom46c16222000-12-22 01:43:59 +000085 client_key, found, NULL);
Damien Miller95def091999-11-25 00:26:21 +110086 restore_uid();
87 }
88 xfree(user_hostfile);
89 }
Damien Miller450a7a12000-03-26 13:04:51 +100090 key_free(client_key);
91 key_free(found);
Damien Millerd4a8b7e1999-10-27 13:42:43 +100092
Damien Miller95def091999-11-25 00:26:21 +110093 if (host_status != HOST_OK) {
94 debug("Rhosts with RSA host authentication denied: unknown or invalid host key");
95 packet_send_debug("Your host key cannot be verified: unknown or invalid host key.");
96 return 0;
97 }
98 /* A matching host key was found and is known. */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100099
Damien Miller95def091999-11-25 00:26:21 +1100100 /* Perform the challenge-response dialog with the client for the host key. */
Damien Miller450a7a12000-03-26 13:04:51 +1000101 if (!auth_rsa_challenge_dialog(client_host_key)) {
Damien Miller95def091999-11-25 00:26:21 +1100102 log("Client on %.800s failed to respond correctly to host authentication.",
103 canonical_hostname);
104 return 0;
105 }
Damien Miller5428f641999-11-25 11:54:57 +1100106 /*
107 * We have authenticated the user using .rhosts or /etc/hosts.equiv,
108 * and the host using RSA. We accept the authentication.
109 */
Damien Miller95def091999-11-25 00:26:21 +1100110
111 verbose("Rhosts with RSA host authentication accepted for %.100s, %.100s on %.700s.",
Damien Miller450a7a12000-03-26 13:04:51 +1000112 pw->pw_name, client_user, canonical_hostname);
Damien Miller95def091999-11-25 00:26:21 +1100113 packet_send_debug("Rhosts with RSA host authentication accepted.");
114 return 1;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000115}