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Damien Miller7acefbb2014-07-18 14:11:24 +10001/* $OpenBSD: auth-rh-rsa.c,v 1.44 2014/07/15 15:54:14 millert Exp $ */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002/*
Damien Miller95def091999-11-25 00:26:21 +11003 * Author: Tatu Ylonen <ylo@cs.hut.fi>
Damien Miller95def091999-11-25 00:26:21 +11004 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * All rights reserved
Damien Miller95def091999-11-25 00:26:21 +11006 * Rhosts or /etc/hosts.equiv authentication combined with RSA host
7 * authentication.
8 *
Damien Millere4340be2000-09-16 13:29:08 +11009 * As far as I am concerned, the code I have written for this software
10 * can be used freely for any purpose. Any derived versions of this
11 * software must be clearly marked as such, and if the derived work is
12 * incompatible with the protocol description in the RFC file, it must be
13 * called by a name other than "ssh" or "Secure Shell".
Damien Miller95def091999-11-25 00:26:21 +110014 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100015
16#include "includes.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100017
Damien Miller9f2abc42006-07-10 20:53:08 +100018#include <sys/types.h>
19
20#include <pwd.h>
Damien Millerd7834352006-08-05 12:39:39 +100021#include <stdarg.h>
Damien Miller9f2abc42006-07-10 20:53:08 +100022
Damien Millerd4a8b7e1999-10-27 13:42:43 +100023#include "packet.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100024#include "uidswap.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000025#include "log.h"
Damien Millerd7834352006-08-05 12:39:39 +100026#include "buffer.h"
Damien Miller7acefbb2014-07-18 14:11:24 +100027#include "misc.h"
Damien Miller32265091999-11-12 11:33:04 +110028#include "servconf.h"
Damien Miller450a7a12000-03-26 13:04:51 +100029#include "key.h"
30#include "hostfile.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000031#include "pathnames.h"
32#include "auth.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000033#include "canohost.h"
Damien Millerd7834352006-08-05 12:39:39 +100034#ifdef GSSAPI
35#include "ssh-gss.h"
36#endif
Ben Lindstrom7a2073c2002-03-22 02:30:41 +000037#include "monitor_wrap.h"
38
Ben Lindstrom186b7da2002-03-22 01:20:32 +000039/* import */
40extern ServerOptions options;
41
Damien Miller4af51302000-04-16 11:18:38 +100042int
Ben Lindstrom186b7da2002-03-22 01:20:32 +000043auth_rhosts_rsa_key_allowed(struct passwd *pw, char *cuser, char *chost,
44 Key *client_host_key)
Damien Millerd4a8b7e1999-10-27 13:42:43 +100045{
Damien Miller95def091999-11-25 00:26:21 +110046 HostStatus host_status;
Damien Millerd4a8b7e1999-10-27 13:42:43 +100047
Damien Miller1aed65e2010-03-04 21:53:35 +110048 if (auth_key_is_revoked(client_host_key))
49 return 0;
50
Damien Miller95def091999-11-25 00:26:21 +110051 /* Check if we would accept it using rhosts authentication. */
Ben Lindstrom186b7da2002-03-22 01:20:32 +000052 if (!auth_rhosts(pw, cuser))
Damien Miller95def091999-11-25 00:26:21 +110053 return 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +100054
Damien Millerd221ca62002-01-22 23:11:00 +110055 host_status = check_key_in_hostfiles(pw, client_host_key,
Ben Lindstrom186b7da2002-03-22 01:20:32 +000056 chost, _PATH_SSH_SYSTEM_HOSTFILE,
Ben Lindstroma4789ef2001-06-25 04:40:49 +000057 options.ignore_user_known_hosts ? NULL : _PATH_SSH_USER_HOSTFILE);
Damien Miller33e511e1999-11-11 11:43:13 +110058
Ben Lindstrom6328ab32002-03-22 02:54:23 +000059 return (host_status == HOST_OK);
Ben Lindstrom186b7da2002-03-22 01:20:32 +000060}
61
62/*
63 * Tries to authenticate the user using the .rhosts file and the host using
64 * its host key. Returns true if authentication succeeds.
65 */
66int
Damien Miller3e3b5142003-11-17 21:13:40 +110067auth_rhosts_rsa(Authctxt *authctxt, char *cuser, Key *client_host_key)
Ben Lindstrom186b7da2002-03-22 01:20:32 +000068{
69 char *chost;
Damien Miller3e3b5142003-11-17 21:13:40 +110070 struct passwd *pw = authctxt->pw;
Ben Lindstrom186b7da2002-03-22 01:20:32 +000071
72 debug("Trying rhosts with RSA host authentication for client user %.100s",
73 cuser);
74
Damien Miller3e3b5142003-11-17 21:13:40 +110075 if (!authctxt->valid || client_host_key == NULL ||
Ben Lindstrom186b7da2002-03-22 01:20:32 +000076 client_host_key->rsa == NULL)
77 return 0;
78
Damien Miller3a961dc2003-06-03 10:25:48 +100079 chost = (char *)get_canonical_hostname(options.use_dns);
Ben Lindstrom186b7da2002-03-22 01:20:32 +000080 debug("Rhosts RSA authentication: canonical host %.900s", chost);
81
Ben Lindstrom7a2073c2002-03-22 02:30:41 +000082 if (!PRIVSEP(auth_rhosts_rsa_key_allowed(pw, cuser, chost, client_host_key))) {
Damien Miller95def091999-11-25 00:26:21 +110083 debug("Rhosts with RSA host authentication denied: unknown or invalid host key");
84 packet_send_debug("Your host key cannot be verified: unknown or invalid host key.");
85 return 0;
86 }
87 /* A matching host key was found and is known. */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100088
Damien Miller95def091999-11-25 00:26:21 +110089 /* Perform the challenge-response dialog with the client for the host key. */
Ben Lindstrom9c8aefe2002-03-22 01:12:58 +000090 if (!auth_rsa_challenge_dialog(client_host_key)) {
Damien Miller996acd22003-04-09 20:59:48 +100091 logit("Client on %.800s failed to respond correctly to host authentication.",
Ben Lindstrom186b7da2002-03-22 01:20:32 +000092 chost);
Damien Miller95def091999-11-25 00:26:21 +110093 return 0;
94 }
Damien Miller5428f641999-11-25 11:54:57 +110095 /*
96 * We have authenticated the user using .rhosts or /etc/hosts.equiv,
97 * and the host using RSA. We accept the authentication.
98 */
Damien Miller95def091999-11-25 00:26:21 +110099
100 verbose("Rhosts with RSA host authentication accepted for %.100s, %.100s on %.700s.",
Damien Miller0dc1bef2005-07-17 17:22:45 +1000101 pw->pw_name, cuser, chost);
Damien Miller95def091999-11-25 00:26:21 +1100102 packet_send_debug("Rhosts with RSA host authentication accepted.");
103 return 1;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000104}