2 * CIFS user-space helper.
3 * Copyright (C) Igor Mammedov (niallain@gmail.com) 2007
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 something like the
9 * following lines to /etc/request-key.conf file:
11 create cifs.spnego * * /usr/local/sbin/cifs.upcall %k
12 create dns_resolver * * /usr/local/sbin/cifs.upcall %k
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
30 #include "cifs_spnego.h"
32 const char *CIFSSPNEGO_VERSION = "1.1";
33 static const char *prog = "cifs.upcall";
34 typedef enum _secType {
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.
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"
54 * secblob - pointer for spnego wrapped AP-REQ data to be stored
55 * sess_key- pointer for SessionKey data to be stored
57 * ret: 0 - success, others - failure
59 int handle_krb5_mech(const char *oid, const char *principal,
60 DATA_BLOB * secblob, DATA_BLOB * sess_key)
63 DATA_BLOB tkt, tkt_wrapped;
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);
72 /* wrap that up in a nice GSS-API wrapping */
73 tkt_wrapped = spnego_gen_krb5_wrap(tkt, TOK_ID_KRB_AP_REQ);
75 /* and wrap that in a shiny SPNEGO wrapper */
76 *secblob = gen_negTokenInit(OID_KERBEROS5, tkt_wrapped);
78 data_blob_free(&tkt_wrapped);
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)
91 int decode_key_description(const char *desc, int *ver, secType_t * sec,
92 char **hostname, uid_t * uid)
96 const char *tkn = desc;
99 pos = index(tkn, ';');
100 if (strncmp(tkn, "host=", 5) == 0) {
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;
122 } else if (strncmp(tkn, "uid=", 4) == 0) {
124 *uid = strtol(tkn + 4, NULL, 16);
126 syslog(LOG_WARNING, "Invalid uid format: %s",
130 retval |= DKD_HAVE_UID;
132 } else if (strncmp(tkn, "ver=", 4) == 0) { /* if version */
134 *ver = strtol(tkn + 4, NULL, 16);
137 "Invalid version format: %s",
141 retval |= DKD_HAVE_VERSION;
151 int cifs_resolver(const key_serial_t key, const char *key_descr)
154 struct addrinfo *addr;
155 char ip[INET6_ADDRSTRLEN];
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, ';');
162 syslog(LOG_WARNING, "invalid key description: %s",
169 /* resolve name to ip */
170 c = getaddrinfo(keyend, NULL, NULL, &addr);
172 syslog(LOG_WARNING, "unable to resolve hostname: %s [%s]",
173 keyend, gai_strerror(c));
177 /* conver ip to string form */
178 if (addr->ai_family == AF_INET) {
179 p = &(((struct sockaddr_in *)addr->ai_addr)->sin_addr);
181 p = &(((struct sockaddr_in6 *)addr->ai_addr)->sin6_addr);
183 if (!inet_ntop(addr->ai_family, p, ip, sizeof(ip))) {
184 syslog(LOG_WARNING, "%s: inet_ntop: %s",
185 __FUNCTION__, strerror(errno));
191 c = keyctl_instantiate(key, ip, strlen(ip)+1, 0);
193 syslog(LOG_WARNING, "%s: keyctl_instantiate: %s",
194 __FUNCTION__, strerror(errno));
206 syslog(LOG_WARNING, "Usage: %s [-c] [-v] key_serial", prog);
207 fprintf(stderr, "Usage: %s [-c] [-v] key_serial\n", prog);
210 int main(const int argc, char *const argv[])
212 struct cifs_spnego_msg *keydata = NULL;
213 DATA_BLOB secblob = data_blob_null;
214 DATA_BLOB sess_key = data_blob_null;
216 key_serial_t key = 0;
220 int kernel_upcall_version;
221 int c, use_cifs_service_prefix = 0;
222 char *buf, *hostname = NULL;
224 openlog(prog, 0, LOG_DAEMON);
226 while ((c = getopt(argc, argv, "cv")) != -1) {
229 use_cifs_service_prefix = 1;
233 printf("version: %s\n", CIFSSPNEGO_VERSION);
237 syslog(LOG_WARNING, "unknown option: %c", c);
243 /* is there a key? */
244 if (argc <= optind) {
249 /* get key and keyring values */
251 key = strtol(argv[optind], NULL, 10);
254 syslog(LOG_WARNING, "Invalid key format: %s", strerror(errno));
258 rc = keyctl_describe_alloc(key, &buf);
260 syslog(LOG_WARNING, "keyctl_describe_alloc failed: %s",
266 if ((strncmp(buf, "cifs.resolver", sizeof("cifs.resolver")-1) == 0) ||
267 (strncmp(buf, "dns_resolver", sizeof("dns_resolver")-1) == 0)) {
268 rc = cifs_resolver(key, buf);
272 rc = decode_key_description(buf, &kernel_upcall_version, §ype,
274 if ((rc & DKD_MUSTHAVE_SET) != DKD_MUSTHAVE_SET) {
276 "unable to get from description necessary params");
283 if (kernel_upcall_version != CIFS_SPNEGO_UPCALL_VERSION) {
285 "incompatible kernel upcall version: 0x%x",
286 kernel_upcall_version);
291 if (rc & DKD_HAVE_UID) {
294 syslog(LOG_WARNING, "setuid: %s", strerror(errno));
299 /* BB: someday upcall SPNEGO blob could be checked here to decide
300 * what mech to use */
302 // do mech specific authorization
308 /* for "cifs/" service name + terminating 0 */
309 len = strlen(hostname) + 5 + 1;
310 princ = SMB_XMALLOC_ARRAY(char, len);
315 if (use_cifs_service_prefix) {
316 strlcpy(princ, "cifs/", len);
318 strlcpy(princ, "host/", len);
320 strlcpy(princ + 5, hostname, len - 5);
322 rc = handle_krb5_mech(OID_KERBEROS5, princ,
323 &secblob, &sess_key);
328 syslog(LOG_WARNING, "sectype: %d is not implemented",
339 /* pack SecurityBLob and SessionKey into downcall packet */
341 sizeof(struct cifs_spnego_msg) + secblob.length + sess_key.length;
342 keydata = (struct cifs_spnego_msg*)SMB_XMALLOC_ARRAY(char, datalen);
347 keydata->version = CIFS_SPNEGO_UPCALL_VERSION;
349 keydata->sesskey_len = sess_key.length;
350 keydata->secblob_len = secblob.length;
351 memcpy(&(keydata->data), sess_key.data, sess_key.length);
352 memcpy(&(keydata->data) + keydata->sesskey_len,
353 secblob.data, secblob.length);
356 rc = keyctl_instantiate(key, keydata, datalen, 0);
358 syslog(LOG_WARNING, "keyctl_instantiate: %s", strerror(errno));
362 /* BB: maybe we need use timeout for key: for example no more then
363 * ticket lifietime? */
364 /* keyctl_set_timeout( key, 60); */
367 * on error, negatively instantiate the key ourselves so that we can
368 * make sure the kernel doesn't hang it off of a searchable keyring
369 * and interfere with the next attempt to instantiate the key.
371 if (rc != 0 && key == 0)
372 keyctl_negate(key, 1, KEY_REQKEY_DEFL_DEFAULT);
373 data_blob_free(&secblob);
374 data_blob_free(&sess_key);