1/* $OpenBSD: auth-krb5.c,v 1.19 2006/08/03 03:34:41 deraadt Exp $ */
2/*
3 * Kerberos v5 authentication and ticket-passing routines.
4 *
5 * $xFreeBSD: src/crypto/openssh/auth-krb5.c,v 1.6 2001/02/13 16:58:04 assar Exp$
6 */
7/*
8 * Copyright (c) 2002 Daniel Kouril. All rights reserved.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31#include "includes.h"
32__RCSID("$FreeBSD: head/crypto/openssh/auth-krb5.c 162856 2006-09-30 13:38:06Z des $");
33
34#include <sys/types.h>
35#include <pwd.h>
36#include <stdarg.h>
37
38#include "xmalloc.h"
39#include "ssh.h"
40#include "ssh1.h"
41#include "packet.h"
42#include "log.h"
43#include "buffer.h"
44#include "servconf.h"
45#include "uidswap.h"
46#include "key.h"
47#include "hostfile.h"
48#include "auth.h"
49
50#ifdef KRB5
51#include <errno.h>
52#include <unistd.h>
53#include <string.h>
54#include <krb5.h>
55
56extern ServerOptions options;
57
58static int
59krb5_init(void *context)
60{
61 Authctxt *authctxt = (Authctxt *)context;
62 krb5_error_code problem;
63
64 if (authctxt->krb5_ctx == NULL) {
65 problem = krb5_init_context(&authctxt->krb5_ctx);
66 if (problem)
67 return (problem);
68 }
69 return (0);
70}
71
72int
73auth_krb5_password(Authctxt *authctxt, const char *password)
74{
75#ifndef HEIMDAL
76 krb5_creds creds;
77 krb5_principal server;
78#endif
79 krb5_error_code problem;
80 krb5_ccache ccache = NULL;
81 int len;
82
83 temporarily_use_uid(authctxt->pw);
84
85 problem = krb5_init(authctxt);
86 if (problem)
87 goto out;
88
89 problem = krb5_parse_name(authctxt->krb5_ctx, authctxt->pw->pw_name,
90 &authctxt->krb5_user);
91 if (problem)
92 goto out;
93
94#ifdef HEIMDAL
95 problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_mcc_ops, &ccache);
96 if (problem)
97 goto out;
98
99 problem = krb5_cc_initialize(authctxt->krb5_ctx, ccache,
100 authctxt->krb5_user);
101 if (problem)
102 goto out;
103
104 restore_uid();
105
106 problem = krb5_verify_user(authctxt->krb5_ctx, authctxt->krb5_user,
107 ccache, password, 1, NULL);
108
109 temporarily_use_uid(authctxt->pw);
110
111 if (problem)
112 goto out;
113
114 problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_fcc_ops,
115 &authctxt->krb5_fwd_ccache);
116 if (problem)
117 goto out;
118
119 problem = krb5_cc_copy_cache(authctxt->krb5_ctx, ccache,
120 authctxt->krb5_fwd_ccache);
121 krb5_cc_destroy(authctxt->krb5_ctx, ccache);
122 ccache = NULL;
123 if (problem)
124 goto out;
125
126#else
127 problem = krb5_get_init_creds_password(authctxt->krb5_ctx, &creds,
128 authctxt->krb5_user, (char *)password, NULL, NULL, 0, NULL, NULL);
129 if (problem)
130 goto out;
131
132 problem = krb5_sname_to_principal(authctxt->krb5_ctx, NULL, NULL,
133 KRB5_NT_SRV_HST, &server);
134 if (problem)
135 goto out;
136
137 restore_uid();
138 problem = krb5_verify_init_creds(authctxt->krb5_ctx, &creds, server,
139 NULL, NULL, NULL);
140 krb5_free_principal(authctxt->krb5_ctx, server);
141 temporarily_use_uid(authctxt->pw);
142 if (problem)
143 goto out;
144
145 if (!krb5_kuserok(authctxt->krb5_ctx, authctxt->krb5_user,
146 authctxt->pw->pw_name)) {
147 problem = -1;
148 goto out;
149 }
150
151 problem = ssh_krb5_cc_gen(authctxt->krb5_ctx, &authctxt->krb5_fwd_ccache);
152 if (problem)
153 goto out;
154
155 problem = krb5_cc_initialize(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache,
156 authctxt->krb5_user);
157 if (problem)
158 goto out;
159
160 problem= krb5_cc_store_cred(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache,
161 &creds);
162 if (problem)
163 goto out;
164#endif
165
166 authctxt->krb5_ticket_file = (char *)krb5_cc_get_name(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache);
167
168 len = strlen(authctxt->krb5_ticket_file) + 6;
169 authctxt->krb5_ccname = xmalloc(len);
170 snprintf(authctxt->krb5_ccname, len, "FILE:%s",
171 authctxt->krb5_ticket_file);
172
173#ifdef USE_PAM
174 if (options.use_pam)
175 do_pam_putenv("KRB5CCNAME", authctxt->krb5_ccname);
176#endif
177
178 out:
179 restore_uid();
180
181 if (problem) {
182 if (ccache)
183 krb5_cc_destroy(authctxt->krb5_ctx, ccache);
184
185 if (authctxt->krb5_ctx != NULL && problem!=-1)
186 debug("Kerberos password authentication failed: %s",
187 krb5_get_err_text(authctxt->krb5_ctx, problem));
188 else
189 debug("Kerberos password authentication failed: %d",
190 problem);
191
192 krb5_cleanup_proc(authctxt);
193
194 if (options.kerberos_or_local_passwd)
195 return (-1);
196 else
197 return (0);
198 }
199 return (authctxt->valid ? 1 : 0);
200}
201
202void
203krb5_cleanup_proc(Authctxt *authctxt)
204{
205 debug("krb5_cleanup_proc called");
206 if (authctxt->krb5_fwd_ccache) {
207 krb5_cc_destroy(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache);
208 authctxt->krb5_fwd_ccache = NULL;
209 }
210 if (authctxt->krb5_user) {
211 krb5_free_principal(authctxt->krb5_ctx, authctxt->krb5_user);
212 authctxt->krb5_user = NULL;
213 }
214 if (authctxt->krb5_ctx) {
215 krb5_free_context(authctxt->krb5_ctx);
216 authctxt->krb5_ctx = NULL;
217 }
218}
219
220#ifndef HEIMDAL
221krb5_error_code
222ssh_krb5_cc_gen(krb5_context ctx, krb5_ccache *ccache) {
223 int tmpfd, ret;
224 char ccname[40];
225 mode_t old_umask;
226
227 ret = snprintf(ccname, sizeof(ccname),
228 "FILE:/tmp/krb5cc_%d_XXXXXXXXXX", geteuid());
229 if (ret < 0 || (size_t)ret >= sizeof(ccname))
230 return ENOMEM;
231
232 old_umask = umask(0177);
233 tmpfd = mkstemp(ccname + strlen("FILE:"));
234 umask(old_umask);
235 if (tmpfd == -1) {
236 logit("mkstemp(): %.100s", strerror(errno));
237 return errno;
238 }
239
240 if (fchmod(tmpfd,S_IRUSR | S_IWUSR) == -1) {
241 logit("fchmod(): %.100s", strerror(errno));
242 close(tmpfd);
243 return errno;
244 }
245 close(tmpfd);
246
247 return (krb5_cc_resolve(ctx, ccname, ccache));
248}
249#endif /* !HEIMDAL */
250#endif /* KRB5 */