source: branches/samba-3.2.x/source/client/cifs.spnego.c@ 302

Last change on this file since 302 was 133, checked in by Paul Smedley, 17 years ago

Update trunk to 3.2.0pre3
File size: 9.0 KB
Line 
1/*
2* CIFS SPNEGO user-space helper.
3* Copyright (C) Igor Mammedov (niallain@gmail.com) 2007
4*
5* Used by /sbin/request-key for handling
6* cifs upcall for kerberos authorization of access to share and
7* cifs upcall for DFS srver name resolving (IPv4/IPv6 aware).
8* You should have keyutils installed and add following line to
9* /etc/request-key.conf file
10
11create cifs.spnego * * /usr/local/sbin/cifs.spnego [-v][-c] %k
12create cifs.resolver * * /usr/local/sbin/cifs.spnego [-v] %k
13
14* This program is free software; you can redistribute it and/or modify
15* it under the terms of the GNU General Public License as published by
16* the Free Software Foundation; either version 2 of the License, or
17* (at your option) any later version.
18* This program is distributed in the hope that it will be useful,
19* but WITHOUT ANY WARRANTY; without even the implied warranty of
20* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21* GNU General Public License for more details.
22* You should have received a copy of the GNU General Public License
23* along with this program; if not, write to the Free Software
24* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
25*/
26
27#include "includes.h"
28#include <keyutils.h>
29
30#include "cifs_spnego.h"
31
32const char *CIFSSPNEGO_VERSION = "1.1";
33static const char *prog = "cifs.spnego";
34typedef enum _secType {
35 KRB5,
36 MS_KRB5
37} secType_t;
38
39/*
40 * Prepares AP-REQ data for mechToken and gets session key
41 * Uses credentials from cache. It will not ask for password
42 * you should receive credentials for yuor name manually using
43 * kinit or whatever you wish.
44 *
45 * in:
46 * oid - string with OID/ Could be OID_KERBEROS5
47 * or OID_KERBEROS5_OLD
48 * principal - Service name.
49 * Could be "cifs/FQDN" for KRB5 OID
50 * or for MS_KRB5 OID style server principal
51 * like "pdc$@YOUR.REALM.NAME"
52 *
53 * out:
54 * secblob - pointer for spnego wrapped AP-REQ data to be stored
55 * sess_key- pointer for SessionKey data to be stored
56 *
57 * ret: 0 - success, others - failure
58*/
59int handle_krb5_mech(const char *oid, const char *principal,
60 DATA_BLOB * secblob, DATA_BLOB * sess_key)
61{
62 int retval;
63 DATA_BLOB tkt, tkt_wrapped;
64
65 /* get a kerberos ticket for the service and extract the session key */
66 retval = cli_krb5_get_ticket(principal, 0,
67 &tkt, sess_key, 0, NULL, NULL);
68
69 if (retval)
70 return retval;
71
72 /* wrap that up in a nice GSS-API wrapping */
73 tkt_wrapped = spnego_gen_krb5_wrap(tkt, TOK_ID_KRB_AP_REQ);
74
75 /* and wrap that in a shiny SPNEGO wrapper */
76 *secblob = gen_negTokenInit(OID_KERBEROS5, tkt_wrapped);
77
78 data_blob_free(&tkt_wrapped);
79 data_blob_free(&tkt);
80 return retval;
81}
82
83#define DKD_HAVE_HOSTNAME 1
84#define DKD_HAVE_VERSION 2
85#define DKD_HAVE_SEC 4
86#define DKD_HAVE_IPV4 8
87#define DKD_HAVE_IPV6 16
88#define DKD_HAVE_UID 32
89#define DKD_MUSTHAVE_SET (DKD_HAVE_HOSTNAME|DKD_HAVE_VERSION|DKD_HAVE_SEC)
90
91int decode_key_description(const char *desc, int *ver, secType_t * sec,
92 char **hostname, uid_t * uid)
93{
94 int retval = 0;
95 char *pos;
96 const char *tkn = desc;
97
98 do {
99 pos = index(tkn, ';');
100 if (strncmp(tkn, "host=", 5) == 0) {
101 int len;
102
103 if (pos == NULL) {
104 len = strlen(tkn);
105 } else {
106 len = pos - tkn;
107 }
108 len -= 4;
109 SAFE_FREE(*hostname);
110 *hostname = SMB_XMALLOC_ARRAY(char, len);
111 strlcpy(*hostname, tkn + 5, len);
112 retval |= DKD_HAVE_HOSTNAME;
113 } else if (strncmp(tkn, "ipv4=", 5) == 0) {
114 /* BB: do we need it if we have hostname already? */
115 } else if (strncmp(tkn, "ipv6=", 5) == 0) {
116 /* BB: do we need it if we have hostname already? */
117 } else if (strncmp(tkn, "sec=", 4) == 0) {
118 if (strncmp(tkn + 4, "krb5", 4) == 0) {
119 retval |= DKD_HAVE_SEC;
120 *sec = KRB5;
121 }
122 } else if (strncmp(tkn, "uid=", 4) == 0) {
123 errno = 0;
124 *uid = strtol(tkn + 4, NULL, 16);
125 if (errno != 0) {
126 syslog(LOG_WARNING, "Invalid uid format: %s",
127 strerror(errno));
128 return 1;
129 } else {
130 retval |= DKD_HAVE_UID;
131 }
132 } else if (strncmp(tkn, "ver=", 4) == 0) { /* if version */
133 errno = 0;
134 *ver = strtol(tkn + 4, NULL, 16);
135 if (errno != 0) {
136 syslog(LOG_WARNING,
137 "Invalid version format: %s",
138 strerror(errno));
139 return 1;
140 } else {
141 retval |= DKD_HAVE_VERSION;
142 }
143 }
144 if (pos == NULL)
145 break;
146 tkn = pos + 1;
147 } while (tkn);
148 return retval;
149}
150
151int cifs_resolver(const key_serial_t key, const char *key_descr)
152{
153 int c;
154 struct addrinfo *addr;
155 char ip[INET6_ADDRSTRLEN];
156 void *p;
157 const char *keyend = key_descr;
158 /* skip next 4 ';' delimiters to get to description */
159 for (c = 1; c <= 4; c++) {
160 keyend = index(keyend+1, ';');
161 if (!keyend) {
162 syslog(LOG_WARNING, "invalid key description: %s",
163 key_descr);
164 return 1;
165 }
166 }
167 keyend++;
168
169 /* resolve name to ip */
170 c = getaddrinfo(keyend, NULL, NULL, &addr);
171 if (c) {
172 syslog(LOG_WARNING, "unable to resolve hostname: %s [%s]",
173 keyend, gai_strerror(c));
174 return 1;
175 }
176
177 /* conver ip to string form */
178 if (addr->ai_family == AF_INET) {
179 p = &(((struct sockaddr_in *)addr->ai_addr)->sin_addr);
180 } else {
181 p = &(((struct sockaddr_in6 *)addr->ai_addr)->sin6_addr);
182 }
183 if (!inet_ntop(addr->ai_family, p, ip, sizeof(ip))) {
184 syslog(LOG_WARNING, "%s: inet_ntop: %s",
185 __FUNCTION__, strerror(errno));
186 freeaddrinfo(addr);
187 return 1;
188 }
189
190 /* setup key */
191 c = keyctl_instantiate(key, ip, strlen(ip)+1, 0);
192 if (c == -1) {
193 syslog(LOG_WARNING, "%s: keyctl_instantiate: %s",
194 __FUNCTION__, strerror(errno));
195 freeaddrinfo(addr);
196 return 1;
197 }
198
199 freeaddrinfo(addr);
200 return 0;
201}
202
203int main(const int argc, char *const argv[])
204{
205 struct cifs_spnego_msg *keydata = NULL;
206 DATA_BLOB secblob = data_blob_null;
207 DATA_BLOB sess_key = data_blob_null;
208 secType_t sectype;
209 key_serial_t key;
210 size_t datalen;
211 long rc = 1;
212 uid_t uid;
213 int kernel_upcall_version;
214 int c, use_cifs_service_prefix = 0;
215 char *buf, *hostname = NULL;
216
217 openlog(prog, 0, LOG_DAEMON);
218 if (argc < 1) {
219 syslog(LOG_WARNING, "Usage: %s [-c] key_serial", prog);
220 goto out;
221 }
222
223 while ((c = getopt(argc, argv, "cv")) != -1) {
224 switch (c) {
225 case 'c':{
226 use_cifs_service_prefix = 1;
227 break;
228 }
229 case 'v':{
230 syslog(LOG_WARNING, "version: %s", CIFSSPNEGO_VERSION);
231 fprintf(stderr, "version: %s", CIFSSPNEGO_VERSION);
232 break;
233 }
234 default:{
235 syslog(LOG_WARNING, "unknow option: %c", c);
236 goto out;
237 }
238 }
239 }
240 /* get key and keyring values */
241 errno = 0;
242 key = strtol(argv[optind], NULL, 10);
243 if (errno != 0) {
244 syslog(LOG_WARNING, "Invalid key format: %s", strerror(errno));
245 goto out;
246 }
247
248 rc = keyctl_describe_alloc(key, &buf);
249 if (rc == -1) {
250 syslog(LOG_WARNING, "keyctl_describe_alloc failed: %s",
251 strerror(errno));
252 rc = 1;
253 goto out;
254 }
255
256 if (strncmp(buf, "cifs.resolver", sizeof("cifs.resolver")-1) == 0) {
257 rc = cifs_resolver(key, buf);
258 goto out;
259 }
260
261 rc = decode_key_description(buf, &kernel_upcall_version, &sectype,
262 &hostname, &uid);
263 if ((rc & DKD_MUSTHAVE_SET) != DKD_MUSTHAVE_SET) {
264 syslog(LOG_WARNING,
265 "unable to get from description necessary params");
266 rc = 1;
267 SAFE_FREE(buf);
268 goto out;
269 }
270 SAFE_FREE(buf);
271
272 if (kernel_upcall_version != CIFS_SPNEGO_UPCALL_VERSION) {
273 syslog(LOG_WARNING,
274 "incompatible kernel upcall version: 0x%x",
275 kernel_upcall_version);
276 rc = 1;
277 goto out;
278 }
279
280 if (rc & DKD_HAVE_UID) {
281 rc = setuid(uid);
282 if (rc == -1) {
283 syslog(LOG_WARNING, "setuid: %s", strerror(errno));
284 goto out;
285 }
286 }
287
288 /* BB: someday upcall SPNEGO blob could be checked here to decide
289 * what mech to use */
290
291 // do mech specific authorization
292 switch (sectype) {
293 case KRB5:{
294 char *princ;
295 size_t len;
296
297 /* for "cifs/" service name + terminating 0 */
298 len = strlen(hostname) + 5 + 1;
299 princ = SMB_XMALLOC_ARRAY(char, len);
300 if (!princ) {
301 rc = 1;
302 break;
303 }
304 if (use_cifs_service_prefix) {
305 strlcpy(princ, "cifs/", len);
306 } else {
307 strlcpy(princ, "host/", len);
308 }
309 strlcpy(princ + 5, hostname, len - 5);
310
311 rc = handle_krb5_mech(OID_KERBEROS5, princ,
312 &secblob, &sess_key);
313 SAFE_FREE(princ);
314 break;
315 }
316 default:{
317 syslog(LOG_WARNING, "sectype: %d is not implemented",
318 sectype);
319 rc = 1;
320 break;
321 }
322 }
323
324 if (rc) {
325 goto out;
326 }
327
328 /* pack SecurityBLob and SessionKey into downcall packet */
329 datalen =
330 sizeof(struct cifs_spnego_msg) + secblob.length + sess_key.length;
331 keydata = (struct cifs_spnego_msg*)SMB_XMALLOC_ARRAY(char, datalen);
332 if (!keydata) {
333 rc = 1;
334 goto out;
335 }
336 keydata->version = CIFS_SPNEGO_UPCALL_VERSION;
337 keydata->flags = 0;
338 keydata->sesskey_len = sess_key.length;
339 keydata->secblob_len = secblob.length;
340 memcpy(&(keydata->data), sess_key.data, sess_key.length);
341 memcpy(&(keydata->data) + keydata->sesskey_len,
342 secblob.data, secblob.length);
343
344 /* setup key */
345 rc = keyctl_instantiate(key, keydata, datalen, 0);
346 if (rc == -1) {
347 syslog(LOG_WARNING, "keyctl_instantiate: %s", strerror(errno));
348 goto out;
349 }
350
351 /* BB: maybe we need use timeout for key: for example no more then
352 * ticket lifietime? */
353 /* keyctl_set_timeout( key, 60); */
354 out:
355 data_blob_free(&secblob);
356 data_blob_free(&sess_key);
357 SAFE_FREE(hostname);
358 SAFE_FREE(keydata);
359 return rc;
360}
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