2 * SELinux NetLabel Support
4 * This file provides the necessary glue to tie NetLabel into the SELinux
7 * Author: Paul Moore <paul.moore@hp.com>
12 * (c) Copyright Hewlett-Packard Development Company, L.P., 2007, 2008
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.
19 * This program is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
22 * the GNU General Public License for more details.
24 * You should have received a copy of the GNU General Public License
25 * along with this program; if not, write to the Free Software
26 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
30 #include <linux/spinlock.h>
31 #include <linux/rcupdate.h>
33 #include <linux/ipv6.h>
35 #include <net/netlabel.h>
44 * selinux_netlbl_sidlookup_cached - Cache a SID lookup
46 * @secattr: the NetLabel security attributes
50 * Query the SELinux security server to lookup the correct SID for the given
51 * security attributes. If the query is successful, cache the result to speed
52 * up future lookups. Returns zero on success, negative values on failure.
55 static int selinux_netlbl_sidlookup_cached(struct sk_buff *skb,
56 struct netlbl_lsm_secattr *secattr,
61 rc = security_netlbl_secattr_to_sid(secattr, sid);
63 (secattr->flags & NETLBL_SECATTR_CACHEABLE) &&
64 (secattr->flags & NETLBL_SECATTR_CACHE))
65 netlbl_cache_add(skb, secattr);
71 * selinux_netlbl_sock_setsid - Label a socket using the NetLabel mechanism
72 * @sk: the socket to label
75 * Attempt to label a socket using the NetLabel mechanism. Returns zero values
76 * on success, negative values on failure.
79 static int selinux_netlbl_sock_setsid(struct sock *sk)
82 struct sk_security_struct *sksec = sk->sk_security;
83 struct netlbl_lsm_secattr secattr;
85 if (sksec->nlbl_state != NLBL_REQUIRE)
88 netlbl_secattr_init(&secattr);
90 rc = security_netlbl_sid_to_secattr(sksec->sid, &secattr);
92 goto sock_setsid_return;
93 rc = netlbl_sock_setattr(sk, &secattr);
96 sksec->nlbl_state = NLBL_LABELED;
99 sksec->nlbl_state = NLBL_REQSKB;
105 netlbl_secattr_destroy(&secattr);
110 * selinux_netlbl_cache_invalidate - Invalidate the NetLabel cache
113 * Invalidate the NetLabel security attribute mapping cache.
116 void selinux_netlbl_cache_invalidate(void)
118 netlbl_cache_invalidate();
122 * selinux_netlbl_err - Handle a NetLabel packet error
124 * @error: the error code
125 * @gateway: true if host is acting as a gateway, false otherwise
128 * When a packet is dropped due to a call to avc_has_perm() pass the error
129 * code to the NetLabel subsystem so any protocol specific processing can be
130 * done. This is safe to call even if you are unsure if NetLabel labeling is
131 * present on the packet, NetLabel is smart enough to only act when it should.
134 void selinux_netlbl_err(struct sk_buff *skb, int error, int gateway)
136 netlbl_skbuff_err(skb, error, gateway);
140 * selinux_netlbl_sk_security_reset - Reset the NetLabel fields
141 * @ssec: the sk_security_struct
142 * @family: the socket family
145 * Called when the NetLabel state of a sk_security_struct needs to be reset.
146 * The caller is responsibile for all the NetLabel sk_security_struct locking.
149 void selinux_netlbl_sk_security_reset(struct sk_security_struct *ssec,
152 if (family == PF_INET)
153 ssec->nlbl_state = NLBL_REQUIRE;
155 ssec->nlbl_state = NLBL_UNSET;
159 * selinux_netlbl_skbuff_getsid - Get the sid of a packet using NetLabel
161 * @family: protocol family
162 * @type: NetLabel labeling protocol type
166 * Call the NetLabel mechanism to get the security attributes of the given
167 * packet and use those attributes to determine the correct context/SID to
168 * assign to the packet. Returns zero on success, negative values on failure.
171 int selinux_netlbl_skbuff_getsid(struct sk_buff *skb,
177 struct netlbl_lsm_secattr secattr;
179 if (!netlbl_enabled()) {
184 netlbl_secattr_init(&secattr);
185 rc = netlbl_skbuff_getattr(skb, family, &secattr);
186 if (rc == 0 && secattr.flags != NETLBL_SECATTR_NONE)
187 rc = selinux_netlbl_sidlookup_cached(skb, &secattr, sid);
190 *type = secattr.type;
191 netlbl_secattr_destroy(&secattr);
197 * selinux_netlbl_skbuff_setsid - Set the NetLabel on a packet given a sid
199 * @family: protocol family
203 * Call the NetLabel mechanism to set the label of a packet using @sid.
204 * Returns zero on auccess, negative values on failure.
207 int selinux_netlbl_skbuff_setsid(struct sk_buff *skb,
212 struct netlbl_lsm_secattr secattr;
215 /* if this is a locally generated packet check to see if it is already
216 * being labeled by it's parent socket, if it is just exit */
219 struct sk_security_struct *sksec = sk->sk_security;
220 if (sksec->nlbl_state != NLBL_REQSKB)
224 netlbl_secattr_init(&secattr);
225 rc = security_netlbl_sid_to_secattr(sid, &secattr);
227 goto skbuff_setsid_return;
228 rc = netlbl_skbuff_setattr(skb, family, &secattr);
230 skbuff_setsid_return:
231 netlbl_secattr_destroy(&secattr);
236 * selinux_netlbl_inet_conn_established - Netlabel the newly accepted connection
237 * @sk: the new connection
240 * A new connection has been established on @sk so make sure it is labeled
241 * correctly with the NetLabel susbsystem.
244 void selinux_netlbl_inet_conn_established(struct sock *sk, u16 family)
247 struct sk_security_struct *sksec = sk->sk_security;
248 struct netlbl_lsm_secattr secattr;
249 struct inet_sock *sk_inet = inet_sk(sk);
250 struct sockaddr_in addr;
252 if (sksec->nlbl_state != NLBL_REQUIRE)
255 netlbl_secattr_init(&secattr);
256 if (security_netlbl_sid_to_secattr(sksec->sid, &secattr) != 0)
257 goto inet_conn_established_return;
259 rc = netlbl_sock_setattr(sk, &secattr);
262 sksec->nlbl_state = NLBL_LABELED;
265 /* no PF_INET6 support yet because we don't support any IPv6
266 * labeling protocols */
267 if (family != PF_INET) {
268 sksec->nlbl_state = NLBL_UNSET;
269 goto inet_conn_established_return;
272 addr.sin_family = family;
273 addr.sin_addr.s_addr = sk_inet->daddr;
274 if (netlbl_conn_setattr(sk, (struct sockaddr *)&addr,
276 /* we failed to label the connected socket (could be
277 * for a variety of reasons, the actual "why" isn't
278 * important here) so we have to go to our backup plan,
279 * labeling the packets individually in the netfilter
280 * local output hook. this is okay but we need to
281 * adjust the MSS of the connection to take into
282 * account any labeling overhead, since we don't know
283 * the exact overhead at this point we'll use the worst
284 * case value which is 40 bytes for IPv4 */
285 struct inet_connection_sock *sk_conn = inet_csk(sk);
286 sk_conn->icsk_ext_hdr_len += 40 -
287 (sk_inet->opt ? sk_inet->opt->optlen : 0);
288 sk_conn->icsk_sync_mss(sk, sk_conn->icsk_pmtu_cookie);
290 sksec->nlbl_state = NLBL_REQSKB;
292 sksec->nlbl_state = NLBL_CONNLABELED;
295 /* note that we are failing to label the socket which could be
296 * a bad thing since it means traffic could leave the system
297 * without the desired labeling, however, all is not lost as
298 * we have a check in selinux_netlbl_inode_permission() to
299 * pick up the pieces that we might drop here because we can't
300 * return an error code */
304 inet_conn_established_return:
305 netlbl_secattr_destroy(&secattr);
310 * selinux_netlbl_socket_post_create - Label a socket using NetLabel
311 * @sock: the socket to label
314 * Attempt to label a socket using the NetLabel mechanism using the given
315 * SID. Returns zero values on success, negative values on failure.
318 int selinux_netlbl_socket_post_create(struct socket *sock)
320 return selinux_netlbl_sock_setsid(sock->sk);
324 * selinux_netlbl_inode_permission - Verify the socket is NetLabel labeled
325 * @inode: the file descriptor's inode
326 * @mask: the permission mask
329 * Looks at a file's inode and if it is marked as a socket protected by
330 * NetLabel then verify that the socket has been labeled, if not try to label
331 * the socket now with the inode's SID. Returns zero on success, negative
335 int selinux_netlbl_inode_permission(struct inode *inode, int mask)
340 struct sk_security_struct *sksec;
342 if (!S_ISSOCK(inode->i_mode) ||
343 ((mask & (MAY_WRITE | MAY_APPEND)) == 0))
346 sock = SOCKET_I(inode);
348 sksec = sk->sk_security;
349 if (sksec->nlbl_state != NLBL_REQUIRE)
353 bh_lock_sock_nested(sk);
354 if (likely(sksec->nlbl_state == NLBL_REQUIRE))
355 rc = selinux_netlbl_sock_setsid(sk);
365 * selinux_netlbl_sock_rcv_skb - Do an inbound access check using NetLabel
366 * @sksec: the sock's sk_security_struct
368 * @family: protocol family
369 * @ad: the audit data
372 * Fetch the NetLabel security attributes from @skb and perform an access check
373 * against the receiving socket. Returns zero on success, negative values on
377 int selinux_netlbl_sock_rcv_skb(struct sk_security_struct *sksec,
380 struct avc_audit_data *ad)
385 struct netlbl_lsm_secattr secattr;
387 if (!netlbl_enabled())
390 netlbl_secattr_init(&secattr);
391 rc = netlbl_skbuff_getattr(skb, family, &secattr);
392 if (rc == 0 && secattr.flags != NETLBL_SECATTR_NONE)
393 rc = selinux_netlbl_sidlookup_cached(skb, &secattr, &nlbl_sid);
395 nlbl_sid = SECINITSID_UNLABELED;
396 netlbl_secattr_destroy(&secattr);
400 switch (sksec->sclass) {
401 case SECCLASS_UDP_SOCKET:
402 perm = UDP_SOCKET__RECVFROM;
404 case SECCLASS_TCP_SOCKET:
405 perm = TCP_SOCKET__RECVFROM;
408 perm = RAWIP_SOCKET__RECVFROM;
411 rc = avc_has_perm(sksec->sid, nlbl_sid, sksec->sclass, perm, ad);
415 if (nlbl_sid != SECINITSID_UNLABELED)
416 netlbl_skbuff_err(skb, rc, 0);
421 * selinux_netlbl_socket_setsockopt - Do not allow users to remove a NetLabel
423 * @level: the socket level or protocol
424 * @optname: the socket option name
427 * Check the setsockopt() call and if the user is trying to replace the IP
428 * options on a socket and a NetLabel is in place for the socket deny the
429 * access; otherwise allow the access. Returns zero when the access is
430 * allowed, -EACCES when denied, and other negative values on error.
433 int selinux_netlbl_socket_setsockopt(struct socket *sock,
438 struct sock *sk = sock->sk;
439 struct sk_security_struct *sksec = sk->sk_security;
440 struct netlbl_lsm_secattr secattr;
442 if (level == IPPROTO_IP && optname == IP_OPTIONS &&
443 (sksec->nlbl_state == NLBL_LABELED ||
444 sksec->nlbl_state == NLBL_CONNLABELED)) {
445 netlbl_secattr_init(&secattr);
447 rc = netlbl_sock_getattr(sk, &secattr);
449 if (rc == 0 && secattr.flags != NETLBL_SECATTR_NONE)
451 netlbl_secattr_destroy(&secattr);
458 * selinux_netlbl_socket_connect - Label a client-side socket on connect
459 * @sk: the socket to label
460 * @addr: the destination address
463 * Attempt to label a connected socket with NetLabel using the given address.
464 * Returns zero values on success, negative values on failure.
467 int selinux_netlbl_socket_connect(struct sock *sk, struct sockaddr *addr)
470 struct sk_security_struct *sksec = sk->sk_security;
471 struct netlbl_lsm_secattr secattr;
473 if (sksec->nlbl_state != NLBL_REQSKB &&
474 sksec->nlbl_state != NLBL_CONNLABELED)
477 netlbl_secattr_init(&secattr);
479 bh_lock_sock_nested(sk);
481 /* connected sockets are allowed to disconnect when the address family
482 * is set to AF_UNSPEC, if that is what is happening we want to reset
484 if (addr->sa_family == AF_UNSPEC) {
485 netlbl_sock_delattr(sk);
486 sksec->nlbl_state = NLBL_REQSKB;
488 goto socket_connect_return;
490 rc = security_netlbl_sid_to_secattr(sksec->sid, &secattr);
492 goto socket_connect_return;
493 rc = netlbl_conn_setattr(sk, addr, &secattr);
495 goto socket_connect_return;
496 sksec->nlbl_state = NLBL_CONNLABELED;
498 socket_connect_return:
501 netlbl_secattr_destroy(&secattr);