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Damien Millerd7834352006-08-05 12:39:39 +10001/* $OpenBSD: auth-krb5.c,v 1.19 2006/08/03 03:34:41 deraadt Exp $ */
Damien Miller964fed52001-09-25 12:58:23 +10002/*
3 * Kerberos v5 authentication and ticket-passing routines.
Ben Lindstrom6328ab32002-03-22 02:54:23 +00004 *
Damien Miller964fed52001-09-25 12:58:23 +10005 * $FreeBSD: src/crypto/openssh/auth-krb5.c,v 1.6 2001/02/13 16:58:04 assar Exp $
Damien Miller964fed52001-09-25 12:58:23 +10006 */
Ben Lindstromeacc71b2002-03-22 01:22:27 +00007/*
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 */
Damien Miller964fed52001-09-25 12:58:23 +100030
31#include "includes.h"
Ben Lindstrom05764b92002-03-05 01:53:02 +000032
Damien Millerd7834352006-08-05 12:39:39 +100033#include <sys/types.h>
34#include <pwd.h>
35#include <stdarg.h>
36
37#include "xmalloc.h"
Damien Miller964fed52001-09-25 12:58:23 +100038#include "ssh.h"
39#include "ssh1.h"
40#include "packet.h"
Damien Miller964fed52001-09-25 12:58:23 +100041#include "log.h"
Damien Millerd7834352006-08-05 12:39:39 +100042#include "buffer.h"
Damien Miller964fed52001-09-25 12:58:23 +100043#include "servconf.h"
44#include "uidswap.h"
Damien Millerd7834352006-08-05 12:39:39 +100045#include "key.h"
46#include "hostfile.h"
Damien Miller964fed52001-09-25 12:58:23 +100047#include "auth.h"
48
49#ifdef KRB5
Darren Tucker341dae52006-07-13 08:45:14 +100050#include <errno.h>
Damien Millerb8fe89c2006-07-24 14:51:00 +100051#include <unistd.h>
52#include <string.h>
Damien Miller964fed52001-09-25 12:58:23 +100053#include <krb5.h>
54
55extern ServerOptions options;
56
57static int
58krb5_init(void *context)
59{
60 Authctxt *authctxt = (Authctxt *)context;
61 krb5_error_code problem;
Damien Millerdb95e4e2002-02-13 16:56:44 +110062
Damien Miller964fed52001-09-25 12:58:23 +100063 if (authctxt->krb5_ctx == NULL) {
64 problem = krb5_init_context(&authctxt->krb5_ctx);
65 if (problem)
66 return (problem);
Damien Miller964fed52001-09-25 12:58:23 +100067 }
Damien Miller964fed52001-09-25 12:58:23 +100068 return (0);
69}
70
Damien Miller964fed52001-09-25 12:58:23 +100071int
72auth_krb5_password(Authctxt *authctxt, const char *password)
73{
Damien Millerfd4c9ee2002-04-13 11:04:40 +100074#ifndef HEIMDAL
75 krb5_creds creds;
76 krb5_principal server;
Damien Miller787b2ec2003-11-21 23:56:47 +110077#endif
Damien Miller964fed52001-09-25 12:58:23 +100078 krb5_error_code problem;
Darren Tuckerec0943a2003-08-11 22:55:36 +100079 krb5_ccache ccache = NULL;
Damien Miller9c870f92004-04-16 22:47:55 +100080 int len;
Darren Tucker1bf35032009-12-21 10:49:21 +110081 char *client, *platform_client;
82
83 /* get platform-specific kerberos client principal name (if it exists) */
84 platform_client = platform_krb5_get_principal_name(authctxt->pw->pw_name);
85 client = platform_client ? platform_client : authctxt->pw->pw_name;
Damien Millerdb95e4e2002-02-13 16:56:44 +110086
Damien Miller964fed52001-09-25 12:58:23 +100087 temporarily_use_uid(authctxt->pw);
Damien Millerdb95e4e2002-02-13 16:56:44 +110088
Damien Miller964fed52001-09-25 12:58:23 +100089 problem = krb5_init(authctxt);
90 if (problem)
91 goto out;
Damien Millerdb95e4e2002-02-13 16:56:44 +110092
Darren Tucker1bf35032009-12-21 10:49:21 +110093 problem = krb5_parse_name(authctxt->krb5_ctx, client,
Damien Miller964fed52001-09-25 12:58:23 +100094 &authctxt->krb5_user);
95 if (problem)
96 goto out;
Damien Millerdb95e4e2002-02-13 16:56:44 +110097
Damien Millerfd4c9ee2002-04-13 11:04:40 +100098#ifdef HEIMDAL
Darren Tuckerec0943a2003-08-11 22:55:36 +100099 problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_mcc_ops, &ccache);
Damien Miller964fed52001-09-25 12:58:23 +1000100 if (problem)
101 goto out;
Damien Millerdb95e4e2002-02-13 16:56:44 +1100102
Darren Tuckerec0943a2003-08-11 22:55:36 +1000103 problem = krb5_cc_initialize(authctxt->krb5_ctx, ccache,
104 authctxt->krb5_user);
Damien Miller964fed52001-09-25 12:58:23 +1000105 if (problem)
106 goto out;
Damien Millerdb95e4e2002-02-13 16:56:44 +1100107
108 restore_uid();
Damien Miller787b2ec2003-11-21 23:56:47 +1100109
Damien Miller964fed52001-09-25 12:58:23 +1000110 problem = krb5_verify_user(authctxt->krb5_ctx, authctxt->krb5_user,
Darren Tuckerec0943a2003-08-11 22:55:36 +1000111 ccache, password, 1, NULL);
Damien Miller787b2ec2003-11-21 23:56:47 +1100112
Damien Millerdb95e4e2002-02-13 16:56:44 +1100113 temporarily_use_uid(authctxt->pw);
114
Damien Miller964fed52001-09-25 12:58:23 +1000115 if (problem)
116 goto out;
Darren Tuckerec217ad2003-11-22 12:11:06 +1100117
Darren Tuckerec0943a2003-08-11 22:55:36 +1000118 problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_fcc_ops,
119 &authctxt->krb5_fwd_ccache);
120 if (problem)
121 goto out;
122
123 problem = krb5_cc_copy_cache(authctxt->krb5_ctx, ccache,
124 authctxt->krb5_fwd_ccache);
125 krb5_cc_destroy(authctxt->krb5_ctx, ccache);
126 ccache = NULL;
127 if (problem)
128 goto out;
Damien Millerdb95e4e2002-02-13 16:56:44 +1100129
Damien Millerfd4c9ee2002-04-13 11:04:40 +1000130#else
131 problem = krb5_get_init_creds_password(authctxt->krb5_ctx, &creds,
132 authctxt->krb5_user, (char *)password, NULL, NULL, 0, NULL, NULL);
133 if (problem)
134 goto out;
135
136 problem = krb5_sname_to_principal(authctxt->krb5_ctx, NULL, NULL,
137 KRB5_NT_SRV_HST, &server);
138 if (problem)
139 goto out;
140
141 restore_uid();
142 problem = krb5_verify_init_creds(authctxt->krb5_ctx, &creds, server,
143 NULL, NULL, NULL);
144 krb5_free_principal(authctxt->krb5_ctx, server);
145 temporarily_use_uid(authctxt->pw);
146 if (problem)
147 goto out;
Damien Miller787b2ec2003-11-21 23:56:47 +1100148
Darren Tucker1bf35032009-12-21 10:49:21 +1100149 if (!krb5_kuserok(authctxt->krb5_ctx, authctxt->krb5_user, client)) {
Ben Lindstrom5a6abda2002-06-09 19:41:48 +0000150 problem = -1;
Damien Millerfd4c9ee2002-04-13 11:04:40 +1000151 goto out;
Damien Millera8e06ce2003-11-21 23:48:55 +1100152 }
Damien Millerfd4c9ee2002-04-13 11:04:40 +1000153
Darren Tuckera916d142005-07-07 11:50:20 +1000154 problem = ssh_krb5_cc_gen(authctxt->krb5_ctx, &authctxt->krb5_fwd_ccache);
Damien Millerfd4c9ee2002-04-13 11:04:40 +1000155 if (problem)
156 goto out;
157
158 problem = krb5_cc_initialize(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache,
159 authctxt->krb5_user);
160 if (problem)
161 goto out;
Damien Miller787b2ec2003-11-21 23:56:47 +1100162
Damien Millerfd4c9ee2002-04-13 11:04:40 +1000163 problem= krb5_cc_store_cred(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache,
164 &creds);
165 if (problem)
166 goto out;
Damien Miller787b2ec2003-11-21 23:56:47 +1100167#endif
Damien Millerfd4c9ee2002-04-13 11:04:40 +1000168
Damien Miller964fed52001-09-25 12:58:23 +1000169 authctxt->krb5_ticket_file = (char *)krb5_cc_get_name(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache);
Damien Millerdb95e4e2002-02-13 16:56:44 +1100170
Damien Miller9c870f92004-04-16 22:47:55 +1000171 len = strlen(authctxt->krb5_ticket_file) + 6;
172 authctxt->krb5_ccname = xmalloc(len);
173 snprintf(authctxt->krb5_ccname, len, "FILE:%s",
174 authctxt->krb5_ticket_file);
175
Darren Tucker5614d8f2004-09-11 23:32:09 +1000176#ifdef USE_PAM
177 if (options.use_pam)
178 do_pam_putenv("KRB5CCNAME", authctxt->krb5_ccname);
179#endif
180
Damien Miller964fed52001-09-25 12:58:23 +1000181 out:
182 restore_uid();
Darren Tucker1bf35032009-12-21 10:49:21 +1100183
184 if (platform_client != NULL)
185 xfree(platform_client);
Damien Millerdb95e4e2002-02-13 16:56:44 +1100186
Damien Miller964fed52001-09-25 12:58:23 +1000187 if (problem) {
Darren Tuckerec0943a2003-08-11 22:55:36 +1000188 if (ccache)
189 krb5_cc_destroy(authctxt->krb5_ctx, ccache);
190
Damien Millerfd4c9ee2002-04-13 11:04:40 +1000191 if (authctxt->krb5_ctx != NULL && problem!=-1)
Ben Lindstromb8550282002-02-26 17:46:11 +0000192 debug("Kerberos password authentication failed: %s",
193 krb5_get_err_text(authctxt->krb5_ctx, problem));
194 else
195 debug("Kerberos password authentication failed: %d",
196 problem);
Damien Millerdb95e4e2002-02-13 16:56:44 +1100197
Damien Miller964fed52001-09-25 12:58:23 +1000198 krb5_cleanup_proc(authctxt);
Damien Millerdb95e4e2002-02-13 16:56:44 +1100199
Damien Miller964fed52001-09-25 12:58:23 +1000200 if (options.kerberos_or_local_passwd)
201 return (-1);
202 else
203 return (0);
204 }
Darren Tuckerf4732f62005-11-22 19:42:42 +1100205 return (authctxt->valid ? 1 : 0);
Damien Miller964fed52001-09-25 12:58:23 +1000206}
207
208void
Darren Tucker3e33cec2003-10-02 16:12:36 +1000209krb5_cleanup_proc(Authctxt *authctxt)
Damien Miller964fed52001-09-25 12:58:23 +1000210{
Damien Miller964fed52001-09-25 12:58:23 +1000211 debug("krb5_cleanup_proc called");
212 if (authctxt->krb5_fwd_ccache) {
213 krb5_cc_destroy(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache);
214 authctxt->krb5_fwd_ccache = NULL;
215 }
216 if (authctxt->krb5_user) {
217 krb5_free_principal(authctxt->krb5_ctx, authctxt->krb5_user);
218 authctxt->krb5_user = NULL;
219 }
Damien Miller964fed52001-09-25 12:58:23 +1000220 if (authctxt->krb5_ctx) {
221 krb5_free_context(authctxt->krb5_ctx);
222 authctxt->krb5_ctx = NULL;
223 }
224}
225
Darren Tuckera916d142005-07-07 11:50:20 +1000226#ifndef HEIMDAL
227krb5_error_code
228ssh_krb5_cc_gen(krb5_context ctx, krb5_ccache *ccache) {
Damien Miller025bfd12012-04-26 09:52:15 +1000229 int tmpfd, ret, oerrno;
Darren Tuckera916d142005-07-07 11:50:20 +1000230 char ccname[40];
231 mode_t old_umask;
232
233 ret = snprintf(ccname, sizeof(ccname),
234 "FILE:/tmp/krb5cc_%d_XXXXXXXXXX", geteuid());
Darren Tucker618db972005-11-10 14:43:11 +1100235 if (ret < 0 || (size_t)ret >= sizeof(ccname))
Darren Tuckera83f2612005-07-07 20:09:35 +1000236 return ENOMEM;
Darren Tuckera916d142005-07-07 11:50:20 +1000237
238 old_umask = umask(0177);
239 tmpfd = mkstemp(ccname + strlen("FILE:"));
Damien Miller025bfd12012-04-26 09:52:15 +1000240 oerrno = errno;
Darren Tuckera916d142005-07-07 11:50:20 +1000241 umask(old_umask);
242 if (tmpfd == -1) {
Damien Miller025bfd12012-04-26 09:52:15 +1000243 logit("mkstemp(): %.100s", strerror(oerrno));
244 return oerrno;
Darren Tuckera916d142005-07-07 11:50:20 +1000245 }
246
247 if (fchmod(tmpfd,S_IRUSR | S_IWUSR) == -1) {
Damien Miller025bfd12012-04-26 09:52:15 +1000248 oerrno = errno;
249 logit("fchmod(): %.100s", strerror(oerrno));
Darren Tuckera916d142005-07-07 11:50:20 +1000250 close(tmpfd);
Damien Miller025bfd12012-04-26 09:52:15 +1000251 return oerrno;
Darren Tuckera916d142005-07-07 11:50:20 +1000252 }
253 close(tmpfd);
254
255 return (krb5_cc_resolve(ctx, ccname, ccache));
256}
257#endif /* !HEIMDAL */
Damien Miller964fed52001-09-25 12:58:23 +1000258#endif /* KRB5 */