1 /* $OpenBSD: auth-rh-rsa.c,v 1.44 2014/07/15 15:54:14 millert Exp $ */
2 /*
3 * Author: Tatu Ylonen <ylo@cs.hut.fi>
4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * All rights reserved
6 * Rhosts or /etc/hosts.equiv authentication combined with RSA host
7 * authentication.
8 *
9 * 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".
14 */
15
16 #include "includes.h"
17
18 #ifdef WITH_SSH1
19
20 #include <sys/types.h>
21
22 #include <pwd.h>
23 #include <stdarg.h>
24
25 #include "packet.h"
26 #include "uidswap.h"
27 #include "log.h"
28 #include "buffer.h"
29 #include "misc.h"
30 #include "servconf.h"
31 #include "key.h"
32 #include "hostfile.h"
33 #include "pathnames.h"
34 #include "auth.h"
35 #include "canohost.h"
36 #ifdef GSSAPI
37 #include "ssh-gss.h"
38 #endif
39 #include "monitor_wrap.h"
40
41 /* import */
42 extern ServerOptions options;
43
44 int
auth_rhosts_rsa_key_allowed(struct passwd * pw,char * cuser,char * chost,Key * client_host_key)45 auth_rhosts_rsa_key_allowed(struct passwd *pw, char *cuser, char *chost,
46 Key *client_host_key)
47 {
48 HostStatus host_status;
49
50 if (auth_key_is_revoked(client_host_key))
51 return 0;
52
53 /* Check if we would accept it using rhosts authentication. */
54 if (!auth_rhosts(pw, cuser))
55 return 0;
56
57 host_status = check_key_in_hostfiles(pw, client_host_key,
58 chost, _PATH_SSH_SYSTEM_HOSTFILE,
59 options.ignore_user_known_hosts ? NULL : _PATH_SSH_USER_HOSTFILE);
60
61 return (host_status == HOST_OK);
62 }
63
64 /*
65 * Tries to authenticate the user using the .rhosts file and the host using
66 * its host key. Returns true if authentication succeeds.
67 */
68 int
auth_rhosts_rsa(Authctxt * authctxt,char * cuser,Key * client_host_key)69 auth_rhosts_rsa(Authctxt *authctxt, char *cuser, Key *client_host_key)
70 {
71 char *chost;
72 struct passwd *pw = authctxt->pw;
73
74 debug("Trying rhosts with RSA host authentication for client user %.100s",
75 cuser);
76
77 if (!authctxt->valid || client_host_key == NULL ||
78 client_host_key->rsa == NULL)
79 return 0;
80
81 chost = (char *)get_canonical_hostname(options.use_dns);
82 debug("Rhosts RSA authentication: canonical host %.900s", chost);
83
84 if (!PRIVSEP(auth_rhosts_rsa_key_allowed(pw, cuser, chost, client_host_key))) {
85 debug("Rhosts with RSA host authentication denied: unknown or invalid host key");
86 packet_send_debug("Your host key cannot be verified: unknown or invalid host key.");
87 return 0;
88 }
89 /* A matching host key was found and is known. */
90
91 /* Perform the challenge-response dialog with the client for the host key. */
92 if (!auth_rsa_challenge_dialog(client_host_key)) {
93 logit("Client on %.800s failed to respond correctly to host authentication.",
94 chost);
95 return 0;
96 }
97 /*
98 * We have authenticated the user using .rhosts or /etc/hosts.equiv,
99 * and the host using RSA. We accept the authentication.
100 */
101
102 verbose("Rhosts with RSA host authentication accepted for %.100s, %.100s on %.700s.",
103 pw->pw_name, cuser, chost);
104 packet_send_debug("Rhosts with RSA host authentication accepted.");
105 return 1;
106 }
107
108 #endif /* WITH_SSH1 */
109