blob: 91d87f798f8319978b7c32f7c39fcecfd89a52dc [file] [log] [blame]
Damien Miller10a445b2004-07-21 20:49:39 +10001/* $OpenBSD: gss-serv-krb5.c,v 1.3 2004/07/21 10:36:23 djm Exp $ */
Darren Tucker0efd1552003-08-26 11:49:55 +10002
3/*
4 * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR `AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27#include "includes.h"
28
29#ifdef GSSAPI
30#ifdef KRB5
31
32#include "auth.h"
33#include "xmalloc.h"
34#include "log.h"
35#include "servconf.h"
36
37#include "ssh-gss.h"
38
39extern ServerOptions options;
40
Darren Tucker49aaf4a2003-08-26 11:58:16 +100041#ifdef HEIMDAL
Darren Tucker0d27ed12004-02-24 10:37:33 +110042# include <krb5.h>
Darren Tucker49aaf4a2003-08-26 11:58:16 +100043#else
Darren Tucker0d27ed12004-02-24 10:37:33 +110044# ifdef HAVE_GSSAPI_KRB5
45# include <gssapi_krb5.h>
46# elif HAVE_GSSAPI_GSSAPI_KRB5
47# include <gssapi/gssapi_krb5.h>
48# endif
Darren Tucker49aaf4a2003-08-26 11:58:16 +100049#endif
Darren Tucker0efd1552003-08-26 11:49:55 +100050
51static krb5_context krb_context = NULL;
52
53/* Initialise the krb5 library, for the stuff that GSSAPI won't do */
54
Damien Millera8e06ce2003-11-21 23:48:55 +110055static int
Damien Miller10a445b2004-07-21 20:49:39 +100056ssh_gssapi_krb5_init(void)
Darren Tucker0efd1552003-08-26 11:49:55 +100057{
58 krb5_error_code problem;
59
60 if (krb_context != NULL)
61 return 1;
62
63 problem = krb5_init_context(&krb_context);
64 if (problem) {
65 logit("Cannot initialize krb5 context");
66 return 0;
67 }
Ben Lindstroma8104b52004-04-07 04:16:11 +000068#ifdef KRB5_INIT_ETS
Darren Tucker0efd1552003-08-26 11:49:55 +100069 krb5_init_ets(krb_context);
Ben Lindstroma8104b52004-04-07 04:16:11 +000070#endif
Darren Tucker0efd1552003-08-26 11:49:55 +100071
72 return 1;
73}
74
75/* Check if this user is OK to login. This only works with krb5 - other
76 * GSSAPI mechanisms will need their own.
77 * Returns true if the user is OK to log in, otherwise returns 0
78 */
79
80static int
81ssh_gssapi_krb5_userok(ssh_gssapi_client *client, char *name)
82{
83 krb5_principal princ;
84 int retval;
85
86 if (ssh_gssapi_krb5_init() == 0)
87 return 0;
88
89 if ((retval = krb5_parse_name(krb_context, client->exportedname.value,
90 &princ))) {
91 logit("krb5_parse_name(): %.100s",
92 krb5_get_err_text(krb_context, retval));
93 return 0;
94 }
95 if (krb5_kuserok(krb_context, princ, name)) {
96 retval = 1;
97 logit("Authorized to %s, krb5 principal %s (krb5_kuserok)",
98 name, (char *)client->displayname.value);
99 } else
100 retval = 0;
101
102 krb5_free_principal(krb_context, princ);
103 return retval;
104}
105
106
107/* This writes out any forwarded credentials from the structure populated
108 * during userauth. Called after we have setuid to the user */
109
110static void
111ssh_gssapi_krb5_storecreds(ssh_gssapi_client *client)
112{
113 krb5_ccache ccache;
114 krb5_error_code problem;
115 krb5_principal princ;
116 OM_uint32 maj_status, min_status;
Damien Miller34255b92004-02-17 20:33:52 +1100117 int len;
Darren Tucker0efd1552003-08-26 11:49:55 +1000118
119 if (client->creds == NULL) {
120 debug("No credentials stored");
121 return;
122 }
123
124 if (ssh_gssapi_krb5_init() == 0)
125 return;
126
Darren Tucker49aaf4a2003-08-26 11:58:16 +1000127#ifdef HEIMDAL
Darren Tucker0efd1552003-08-26 11:49:55 +1000128 if ((problem = krb5_cc_gen_new(krb_context, &krb5_fcc_ops, &ccache))) {
129 logit("krb5_cc_gen_new(): %.100s",
130 krb5_get_err_text(krb_context, problem));
131 return;
132 }
Darren Tucker49aaf4a2003-08-26 11:58:16 +1000133#else
134 {
135 int tmpfd;
136 char ccname[40];
Darren Tucker06696932004-08-14 23:55:37 +1000137 mode_t old_umask;
Damien Millera8e06ce2003-11-21 23:48:55 +1100138
139 snprintf(ccname, sizeof(ccname),
Darren Tucker49aaf4a2003-08-26 11:58:16 +1000140 "FILE:/tmp/krb5cc_%d_XXXXXX", geteuid());
Damien Millera8e06ce2003-11-21 23:48:55 +1100141
Darren Tucker06696932004-08-14 23:55:37 +1000142 old_umask = umask(0177);
143 tmpfd = mkstemp(ccname + strlen("FILE:"));
144 umask(old_umask);
145 if (tmpfd == -1) {
Darren Tucker49aaf4a2003-08-26 11:58:16 +1000146 logit("mkstemp(): %.100s", strerror(errno));
147 problem = errno;
148 return;
149 }
150 if (fchmod(tmpfd, S_IRUSR | S_IWUSR) == -1) {
151 logit("fchmod(): %.100s", strerror(errno));
152 close(tmpfd);
153 problem = errno;
154 return;
155 }
156 close(tmpfd);
157 if ((problem = krb5_cc_resolve(krb_context, ccname, &ccache))) {
158 logit("krb5_cc_resolve(): %.100s",
159 krb5_get_err_text(krb_context, problem));
160 return;
161 }
162 }
163#endif /* #ifdef HEIMDAL */
Darren Tucker0efd1552003-08-26 11:49:55 +1000164
Damien Millera8e06ce2003-11-21 23:48:55 +1100165 if ((problem = krb5_parse_name(krb_context,
Darren Tucker0efd1552003-08-26 11:49:55 +1000166 client->exportedname.value, &princ))) {
167 logit("krb5_parse_name(): %.100s",
168 krb5_get_err_text(krb_context, problem));
169 krb5_cc_destroy(krb_context, ccache);
170 return;
171 }
172
173 if ((problem = krb5_cc_initialize(krb_context, ccache, princ))) {
174 logit("krb5_cc_initialize(): %.100s",
175 krb5_get_err_text(krb_context, problem));
176 krb5_free_principal(krb_context, princ);
177 krb5_cc_destroy(krb_context, ccache);
178 return;
179 }
180
181 krb5_free_principal(krb_context, princ);
182
Damien Millera8e06ce2003-11-21 23:48:55 +1100183 if ((maj_status = gss_krb5_copy_ccache(&min_status,
Darren Tucker0efd1552003-08-26 11:49:55 +1000184 client->creds, ccache))) {
185 logit("gss_krb5_copy_ccache() failed");
186 krb5_cc_destroy(krb_context, ccache);
187 return;
188 }
189
190 client->store.filename = xstrdup(krb5_cc_get_name(krb_context, ccache));
191 client->store.envvar = "KRB5CCNAME";
Damien Miller34255b92004-02-17 20:33:52 +1100192 len = strlen(client->store.filename) + 6;
193 client->store.envval = xmalloc(len);
194 snprintf(client->store.envval, len, "FILE:%s", client->store.filename);
Darren Tucker0efd1552003-08-26 11:49:55 +1000195
Darren Tucker49aaf4a2003-08-26 11:58:16 +1000196#ifdef USE_PAM
197 if (options.use_pam)
Damien Miller34255b92004-02-17 20:33:52 +1100198 do_pam_putenv(client->store.envvar, client->store.envval);
Darren Tucker49aaf4a2003-08-26 11:58:16 +1000199#endif
200
Darren Tucker0efd1552003-08-26 11:49:55 +1000201 krb5_cc_close(krb_context, ccache);
202
203 return;
204}
205
206ssh_gssapi_mech gssapi_kerberos_mech = {
207 "toWM5Slw5Ew8Mqkay+al2g==",
208 "Kerberos",
209 {9, "\x2A\x86\x48\x86\xF7\x12\x01\x02\x02"},
210 NULL,
211 &ssh_gssapi_krb5_userok,
212 NULL,
213 &ssh_gssapi_krb5_storecreds
214};
215
216#endif /* KRB5 */
217
218#endif /* GSSAPI */