xref: /openbsd-src/usr.bin/ssh/auth-krb5.c (revision 8500990981f885cbe5e6a4958549cacc238b5ae6)
1 /*
2  *    Kerberos v5 authentication and ticket-passing routines.
3  *
4  * $FreeBSD: src/crypto/openssh/auth-krb5.c,v 1.6 2001/02/13 16:58:04 assar Exp $
5  */
6 /*
7  * Copyright (c) 2002 Daniel Kouril.  All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28  */
29 
30 #include "includes.h"
31 RCSID("$OpenBSD: auth-krb5.c,v 1.15 2003/11/21 11:57:02 djm Exp $");
32 
33 #include "ssh.h"
34 #include "ssh1.h"
35 #include "packet.h"
36 #include "xmalloc.h"
37 #include "log.h"
38 #include "servconf.h"
39 #include "uidswap.h"
40 #include "auth.h"
41 
42 #ifdef KRB5
43 #include <krb5.h>
44 
45 extern ServerOptions	 options;
46 
47 static int
48 krb5_init(void *context)
49 {
50 	Authctxt *authctxt = (Authctxt *)context;
51 	krb5_error_code problem;
52 
53 	if (authctxt->krb5_ctx == NULL) {
54 		problem = krb5_init_context(&authctxt->krb5_ctx);
55 		if (problem)
56 			return (problem);
57 		krb5_init_ets(authctxt->krb5_ctx);
58 	}
59 	return (0);
60 }
61 
62 int
63 auth_krb5_password(Authctxt *authctxt, const char *password)
64 {
65 	krb5_error_code problem;
66 	krb5_ccache ccache = NULL;
67 
68 	if (!authctxt->valid)
69 		return (0);
70 
71 	temporarily_use_uid(authctxt->pw);
72 
73 	problem = krb5_init(authctxt);
74 	if (problem)
75 		goto out;
76 
77 	problem = krb5_parse_name(authctxt->krb5_ctx, authctxt->pw->pw_name,
78 		    &authctxt->krb5_user);
79 	if (problem)
80 		goto out;
81 
82 	problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_mcc_ops, &ccache);
83 	if (problem)
84 		goto out;
85 
86 	problem = krb5_cc_initialize(authctxt->krb5_ctx, ccache,
87 		authctxt->krb5_user);
88 	if (problem)
89 		goto out;
90 
91 	restore_uid();
92 
93 	problem = krb5_verify_user(authctxt->krb5_ctx, authctxt->krb5_user,
94 	    ccache, password, 1, NULL);
95 
96 	temporarily_use_uid(authctxt->pw);
97 
98 	if (problem)
99 		goto out;
100 
101 	problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_fcc_ops,
102 	    &authctxt->krb5_fwd_ccache);
103 	if (problem)
104 		goto out;
105 
106 	problem = krb5_cc_copy_cache(authctxt->krb5_ctx, ccache,
107 	    authctxt->krb5_fwd_ccache);
108 	krb5_cc_destroy(authctxt->krb5_ctx, ccache);
109 	ccache = NULL;
110 	if (problem)
111 		goto out;
112 
113 	authctxt->krb5_ticket_file = (char *)krb5_cc_get_name(authctxt->krb5_ctx,
114 	    authctxt->krb5_fwd_ccache);
115 
116  out:
117 	restore_uid();
118 
119 	if (problem) {
120 		if (ccache)
121 			krb5_cc_destroy(authctxt->krb5_ctx, ccache);
122 
123 		if (authctxt->krb5_ctx != NULL)
124 			debug("Kerberos password authentication failed: %s",
125 			    krb5_get_err_text(authctxt->krb5_ctx, problem));
126 		else
127 			debug("Kerberos password authentication failed: %d",
128 			    problem);
129 
130 		krb5_cleanup_proc(authctxt);
131 
132 		if (options.kerberos_or_local_passwd)
133 			return (-1);
134 		else
135 			return (0);
136 	}
137 	return (1);
138 }
139 
140 void
141 krb5_cleanup_proc(Authctxt *authctxt)
142 {
143 	debug("krb5_cleanup_proc called");
144 	if (authctxt->krb5_fwd_ccache) {
145 		krb5_cc_destroy(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache);
146 		authctxt->krb5_fwd_ccache = NULL;
147 	}
148 	if (authctxt->krb5_user) {
149 		krb5_free_principal(authctxt->krb5_ctx, authctxt->krb5_user);
150 		authctxt->krb5_user = NULL;
151 	}
152 	if (authctxt->krb5_ctx) {
153 		krb5_free_context(authctxt->krb5_ctx);
154 		authctxt->krb5_ctx = NULL;
155 	}
156 }
157 
158 #endif /* KRB5 */
159