1/*
2 * Kerberos v5 authentication and ticket-passing routines.
3 *
4 * $xFreeBSD: src/crypto/openssh/auth-krb5.c,v 1.6 2001/02/13 16:58:04 assar Exp$
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"
31RCSID("$OpenBSD: auth-krb5.c,v 1.16 2005/11/21 09:42:10 dtucker Exp $");
32RCSID("$FreeBSD: head/crypto/openssh/auth-krb5.c 157019 2006-03-22 20:41:37Z des $");
33
34#include "ssh.h"
35#include "ssh1.h"
36#include "packet.h"
37#include "xmalloc.h"
38#include "log.h"
39#include "servconf.h"
40#include "uidswap.h"
41#include "auth.h"
42
43#ifdef KRB5
44#include <krb5.h>
45
46extern ServerOptions options;
47
48static int
49krb5_init(void *context)
50{
51 Authctxt *authctxt = (Authctxt *)context;
52 krb5_error_code problem;
53
54 if (authctxt->krb5_ctx == NULL) {
55 problem = krb5_init_context(&authctxt->krb5_ctx);
56 if (problem)
57 return (problem);
58 }
59 return (0);
60}
61
62int
63auth_krb5_password(Authctxt *authctxt, const char *password)
64{
65#ifndef HEIMDAL
66 krb5_creds creds;
67 krb5_principal server;
68#endif
69 krb5_error_code problem;
70 krb5_ccache ccache = NULL;
71 int len;
72
73 temporarily_use_uid(authctxt->pw);
74
75 problem = krb5_init(authctxt);
76 if (problem)
77 goto out;
78
79 problem = krb5_parse_name(authctxt->krb5_ctx, authctxt->pw->pw_name,
80 &authctxt->krb5_user);
81 if (problem)
82 goto out;
83
84#ifdef HEIMDAL
85 problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_mcc_ops, &ccache);
86 if (problem)
87 goto out;
88
89 problem = krb5_cc_initialize(authctxt->krb5_ctx, ccache,
90 authctxt->krb5_user);
91 if (problem)
92 goto out;
93
94 restore_uid();
95
96 problem = krb5_verify_user(authctxt->krb5_ctx, authctxt->krb5_user,
97 ccache, password, 1, NULL);
98
99 temporarily_use_uid(authctxt->pw);
100
101 if (problem)
102 goto out;
103
104 problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_fcc_ops,
105 &authctxt->krb5_fwd_ccache);
106 if (problem)
107 goto out;
108
109 problem = krb5_cc_copy_cache(authctxt->krb5_ctx, ccache,
110 authctxt->krb5_fwd_ccache);
111 krb5_cc_destroy(authctxt->krb5_ctx, ccache);
112 ccache = NULL;
113 if (problem)
114 goto out;
115
116#else
117 problem = krb5_get_init_creds_password(authctxt->krb5_ctx, &creds,
118 authctxt->krb5_user, (char *)password, NULL, NULL, 0, NULL, NULL);
119 if (problem)
120 goto out;
121
122 problem = krb5_sname_to_principal(authctxt->krb5_ctx, NULL, NULL,
123 KRB5_NT_SRV_HST, &server);
124 if (problem)
125 goto out;
126
127 restore_uid();
128 problem = krb5_verify_init_creds(authctxt->krb5_ctx, &creds, server,
129 NULL, NULL, NULL);
130 krb5_free_principal(authctxt->krb5_ctx, server);
131 temporarily_use_uid(authctxt->pw);
132 if (problem)
133 goto out;
134
135 if (!krb5_kuserok(authctxt->krb5_ctx, authctxt->krb5_user,
136 authctxt->pw->pw_name)) {
137 problem = -1;
138 goto out;
139 }
140
141 problem = ssh_krb5_cc_gen(authctxt->krb5_ctx, &authctxt->krb5_fwd_ccache);
142 if (problem)
143 goto out;
144
145 problem = krb5_cc_initialize(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache,
146 authctxt->krb5_user);
147 if (problem)
148 goto out;
149
150 problem= krb5_cc_store_cred(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache,
151 &creds);
152 if (problem)
153 goto out;
154#endif
155
156 authctxt->krb5_ticket_file = (char *)krb5_cc_get_name(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache);
157
158 len = strlen(authctxt->krb5_ticket_file) + 6;
159 authctxt->krb5_ccname = xmalloc(len);
160 snprintf(authctxt->krb5_ccname, len, "FILE:%s",
161 authctxt->krb5_ticket_file);
162
163#ifdef USE_PAM
164 if (options.use_pam)
165 do_pam_putenv("KRB5CCNAME", authctxt->krb5_ccname);
166#endif
167
168 out:
169 restore_uid();
170
171 if (problem) {
172 if (ccache)
173 krb5_cc_destroy(authctxt->krb5_ctx, ccache);
174
175 if (authctxt->krb5_ctx != NULL && problem!=-1)
176 debug("Kerberos password authentication failed: %s",
177 krb5_get_err_text(authctxt->krb5_ctx, problem));
178 else
179 debug("Kerberos password authentication failed: %d",
180 problem);
181
182 krb5_cleanup_proc(authctxt);
183
184 if (options.kerberos_or_local_passwd)
185 return (-1);
186 else
187 return (0);
188 }
189 return (authctxt->valid ? 1 : 0);
190}
191
192void
193krb5_cleanup_proc(Authctxt *authctxt)
194{
195 debug("krb5_cleanup_proc called");
196 if (authctxt->krb5_fwd_ccache) {
197 krb5_cc_destroy(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache);
198 authctxt->krb5_fwd_ccache = NULL;
199 }
200 if (authctxt->krb5_user) {
201 krb5_free_principal(authctxt->krb5_ctx, authctxt->krb5_user);
202 authctxt->krb5_user = NULL;
203 }
204 if (authctxt->krb5_ctx) {
205 krb5_free_context(authctxt->krb5_ctx);
206 authctxt->krb5_ctx = NULL;
207 }
208}
209
210#ifndef HEIMDAL
211krb5_error_code
212ssh_krb5_cc_gen(krb5_context ctx, krb5_ccache *ccache) {
213 int tmpfd, ret;
214 char ccname[40];
215 mode_t old_umask;
216
217 ret = snprintf(ccname, sizeof(ccname),
218 "FILE:/tmp/krb5cc_%d_XXXXXXXXXX", geteuid());
219 if (ret < 0 || (size_t)ret >= sizeof(ccname))
220 return ENOMEM;
221
222 old_umask = umask(0177);
223 tmpfd = mkstemp(ccname + strlen("FILE:"));
224 umask(old_umask);
225 if (tmpfd == -1) {
226 logit("mkstemp(): %.100s", strerror(errno));
227 return errno;
228 }
229
230 if (fchmod(tmpfd,S_IRUSR | S_IWUSR) == -1) {
231 logit("fchmod(): %.100s", strerror(errno));
232 close(tmpfd);
233 return errno;
234 }
235 close(tmpfd);
236
237 return (krb5_cc_resolve(ctx, ccname, ccache));
238}
239#endif /* !HEIMDAL */
240#endif /* KRB5 */