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1 | /* $OpenBSD: auth-rh-rsa.c,v 1.42 2006/08/03 03:34:41 deraadt 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 | #include <sys/types.h> | |
19 | ||
20 | #include <pwd.h> | |
21 | #include <stdarg.h> | |
22 | ||
23 | #include "packet.h" | |
24 | #include "uidswap.h" | |
25 | #include "log.h" | |
26 | #include "buffer.h" | |
27 | #include "servconf.h" | |
28 | #include "key.h" | |
29 | #include "hostfile.h" | |
30 | #include "pathnames.h" | |
31 | #include "auth.h" | |
32 | #include "canohost.h" | |
33 | #ifdef GSSAPI | |
34 | #include "ssh-gss.h" | |
35 | #endif | |
36 | #include "monitor_wrap.h" | |
37 | ||
38 | /* import */ | |
39 | extern ServerOptions options; | |
40 | ||
41 | int | |
42 | auth_rhosts_rsa_key_allowed(struct passwd *pw, char *cuser, char *chost, | |
43 | Key *client_host_key) | |
44 | { | |
45 | HostStatus host_status; | |
46 | ||
47 | /* Check if we would accept it using rhosts authentication. */ | |
48 | if (!auth_rhosts(pw, cuser)) | |
49 | return 0; | |
50 | ||
51 | host_status = check_key_in_hostfiles(pw, client_host_key, | |
52 | chost, _PATH_SSH_SYSTEM_HOSTFILE, | |
53 | options.ignore_user_known_hosts ? NULL : _PATH_SSH_USER_HOSTFILE); | |
54 | ||
55 | return (host_status == HOST_OK); | |
56 | } | |
57 | ||
58 | /* | |
59 | * Tries to authenticate the user using the .rhosts file and the host using | |
60 | * its host key. Returns true if authentication succeeds. | |
61 | */ | |
62 | int | |
63 | auth_rhosts_rsa(Authctxt *authctxt, char *cuser, Key *client_host_key) | |
64 | { | |
65 | char *chost; | |
66 | struct passwd *pw = authctxt->pw; | |
67 | ||
68 | debug("Trying rhosts with RSA host authentication for client user %.100s", | |
69 | cuser); | |
70 | ||
71 | if (!authctxt->valid || client_host_key == NULL || | |
72 | client_host_key->rsa == NULL) | |
73 | return 0; | |
74 | ||
75 | chost = (char *)get_canonical_hostname(options.use_dns); | |
76 | debug("Rhosts RSA authentication: canonical host %.900s", chost); | |
77 | ||
78 | if (!PRIVSEP(auth_rhosts_rsa_key_allowed(pw, cuser, chost, client_host_key))) { | |
79 | debug("Rhosts with RSA host authentication denied: unknown or invalid host key"); | |
80 | packet_send_debug("Your host key cannot be verified: unknown or invalid host key."); | |
81 | return 0; | |
82 | } | |
83 | /* A matching host key was found and is known. */ | |
84 | ||
85 | /* Perform the challenge-response dialog with the client for the host key. */ | |
86 | if (!auth_rsa_challenge_dialog(client_host_key)) { | |
87 | logit("Client on %.800s failed to respond correctly to host authentication.", | |
88 | chost); | |
89 | return 0; | |
90 | } | |
91 | /* | |
92 | * We have authenticated the user using .rhosts or /etc/hosts.equiv, | |
93 | * and the host using RSA. We accept the authentication. | |
94 | */ | |
95 | ||
96 | verbose("Rhosts with RSA host authentication accepted for %.100s, %.100s on %.700s.", | |
97 | pw->pw_name, cuser, chost); | |
98 | packet_send_debug("Rhosts with RSA host authentication accepted."); | |
99 | return 1; | |
100 | } |