1 /*
2 * Author: Tatu Ylonen <ylo@cs.hut.fi>
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4 * All rights reserved
5 * Rhosts or /etc/hosts.equiv authentication combined with RSA host
6 * authentication.
7 *
8 * 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".
13 */
14
15 #include "includes.h"
16 RCSID("$OpenBSD: auth-rh-rsa.c,v 1.34 2002/03/25 09:25:06 markus Exp $");
17
18 #pragma ident "%Z%%M% %I% %E% SMI"
19
20 #include "packet.h"
21 #include "uidswap.h"
22 #include "log.h"
23 #include "servconf.h"
24 #include "key.h"
25 #include "hostfile.h"
26 #include "pathnames.h"
27 #include "auth.h"
28 #include "canohost.h"
29
30 /* import */
31 extern ServerOptions options;
32
33 int
auth_rhosts_rsa_key_allowed(struct passwd * pw,char * cuser,char * chost,Key * client_host_key)34 auth_rhosts_rsa_key_allowed(struct passwd *pw, char *cuser, char *chost,
35 Key *client_host_key)
36 {
37 HostStatus host_status;
38
39 /* Check if we would accept it using rhosts authentication. */
40 if (!auth_rhosts(pw, cuser))
41 return 0;
42
43 host_status = check_key_in_hostfiles(pw, client_host_key,
44 chost, _PATH_SSH_SYSTEM_HOSTFILE,
45 options.ignore_user_known_hosts ? NULL : _PATH_SSH_USER_HOSTFILE);
46
47 return (host_status == HOST_OK);
48 }
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 */
54 int
auth_rhosts_rsa(struct passwd * pw,char * cuser,Key * client_host_key)55 auth_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
69 if (!auth_rhosts_rsa_key_allowed(pw, cuser, chost, client_host_key)) {
70 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. */
75
76 /* Perform the challenge-response dialog with the client for the host key. */
77 if (!auth_rsa_challenge_dialog(client_host_key)) {
78 log("Client on %.800s failed to respond correctly to host authentication.",
79 chost);
80 return 0;
81 }
82 /*
83 * We have authenticated the user using .rhosts or /etc/hosts.equiv,
84 * and the host using RSA. We accept the authentication.
85 */
86
87 verbose("Rhosts with RSA host authentication accepted for %.100s, %.100s on %.700s.",
88 pw->pw_name, cuser, chost);
89 packet_send_debug("Rhosts with RSA host authentication accepted.");
90 return 1;
91 }
92