1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * SELinux NetLabel Support
4 *
5 * This file provides the necessary glue to tie NetLabel into the SELinux
6 * subsystem.
7 *
8 * Author: Paul Moore <paul@paul-moore.com>
9 */
10
11/*
12 * (c) Copyright Hewlett-Packard Development Company, L.P., 2007, 2008
13 */
14
15#include <linux/spinlock.h>
16#include <linux/rcupdate.h>
17#include <linux/gfp.h>
18#include <linux/ip.h>
19#include <linux/ipv6.h>
20#include <linux/lsm_hooks.h>
21#include <net/sock.h>
22#include <net/netlabel.h>
23#include <net/ip.h>
24#include <net/ipv6.h>
25
26#include "objsec.h"
27#include "security.h"
28#include "netlabel.h"
29
30/**
31 * selinux_netlbl_sidlookup_cached - Cache a SID lookup
32 * @skb: the packet
33 * @family: the packet's address family
34 * @secattr: the NetLabel security attributes
35 * @sid: the SID
36 *
37 * Description:
38 * Query the SELinux security server to lookup the correct SID for the given
39 * security attributes. If the query is successful, cache the result to speed
40 * up future lookups. Returns zero on success, negative values on failure.
41 *
42 */
43static int selinux_netlbl_sidlookup_cached(struct sk_buff *skb,
44 u16 family,
45 struct netlbl_lsm_secattr *secattr,
46 u32 *sid)
47{
48 int rc;
49
50 rc = security_netlbl_secattr_to_sid(secattr, sid);
51 if (rc == 0 &&
52 (secattr->flags & NETLBL_SECATTR_CACHEABLE) &&
53 (secattr->flags & NETLBL_SECATTR_CACHE))
54 netlbl_cache_add(skb, family, secattr);
55
56 return rc;
57}
58
59/**
60 * selinux_netlbl_sock_genattr - Generate the NetLabel socket secattr
61 * @sk: the socket
62 *
63 * Description:
64 * Generate the NetLabel security attributes for a socket, making full use of
65 * the socket's attribute cache. Returns a pointer to the security attributes
66 * on success, or an ERR_PTR on failure.
67 *
68 */
69static struct netlbl_lsm_secattr *selinux_netlbl_sock_genattr(struct sock *sk)
70{
71 int rc;
72 struct sk_security_struct *sksec = selinux_sock(sock: sk);
73 struct netlbl_lsm_secattr *secattr;
74
75 if (sksec->nlbl_secattr != NULL)
76 return sksec->nlbl_secattr;
77
78 secattr = netlbl_secattr_alloc(GFP_ATOMIC);
79 if (secattr == NULL)
80 return ERR_PTR(error: -ENOMEM);
81
82 rc = security_netlbl_sid_to_secattr(sid: sksec->sid, secattr);
83 if (rc != 0) {
84 netlbl_secattr_free(secattr);
85 return ERR_PTR(error: rc);
86 }
87 sksec->nlbl_secattr = secattr;
88
89 return secattr;
90}
91
92/**
93 * selinux_netlbl_sock_getattr - Get the cached NetLabel secattr
94 * @sk: the socket
95 * @sid: the SID
96 *
97 * Query the socket's cached secattr and if the SID matches the cached value
98 * return the cache, otherwise return NULL.
99 *
100 */
101static struct netlbl_lsm_secattr *selinux_netlbl_sock_getattr(
102 const struct sock *sk,
103 u32 sid)
104{
105 struct sk_security_struct *sksec = selinux_sock(sock: sk);
106 struct netlbl_lsm_secattr *secattr = sksec->nlbl_secattr;
107
108 if (secattr == NULL)
109 return NULL;
110
111 if ((secattr->flags & NETLBL_SECATTR_SECID) &&
112 (secattr->attr.secid == sid))
113 return secattr;
114
115 return NULL;
116}
117
118/**
119 * selinux_netlbl_cache_invalidate - Invalidate the NetLabel cache
120 *
121 * Description:
122 * Invalidate the NetLabel security attribute mapping cache.
123 *
124 */
125void selinux_netlbl_cache_invalidate(void)
126{
127 netlbl_cache_invalidate();
128}
129
130/**
131 * selinux_netlbl_err - Handle a NetLabel packet error
132 * @skb: the packet
133 * @family: the packet's address family
134 * @error: the error code
135 * @gateway: true if host is acting as a gateway, false otherwise
136 *
137 * Description:
138 * When a packet is dropped due to a call to avc_has_perm() pass the error
139 * code to the NetLabel subsystem so any protocol specific processing can be
140 * done. This is safe to call even if you are unsure if NetLabel labeling is
141 * present on the packet, NetLabel is smart enough to only act when it should.
142 *
143 */
144void selinux_netlbl_err(struct sk_buff *skb, u16 family, int error, int gateway)
145{
146 netlbl_skbuff_err(skb, family, error, gateway);
147}
148
149/**
150 * selinux_netlbl_sk_security_free - Free the NetLabel fields
151 * @sksec: the sk_security_struct
152 *
153 * Description:
154 * Free all of the memory in the NetLabel fields of a sk_security_struct.
155 *
156 */
157void selinux_netlbl_sk_security_free(struct sk_security_struct *sksec)
158{
159 if (!sksec->nlbl_secattr)
160 return;
161
162 netlbl_secattr_free(secattr: sksec->nlbl_secattr);
163 sksec->nlbl_secattr = NULL;
164 sksec->nlbl_state = NLBL_UNSET;
165}
166
167/**
168 * selinux_netlbl_sk_security_reset - Reset the NetLabel fields
169 * @sksec: the sk_security_struct
170 *
171 * Description:
172 * Called when the NetLabel state of a sk_security_struct needs to be reset.
173 * The caller is responsible for all the NetLabel sk_security_struct locking.
174 *
175 */
176void selinux_netlbl_sk_security_reset(struct sk_security_struct *sksec)
177{
178 sksec->nlbl_state = NLBL_UNSET;
179}
180
181/**
182 * selinux_netlbl_skbuff_getsid - Get the sid of a packet using NetLabel
183 * @skb: the packet
184 * @family: protocol family
185 * @type: NetLabel labeling protocol type
186 * @sid: the SID
187 *
188 * Description:
189 * Call the NetLabel mechanism to get the security attributes of the given
190 * packet and use those attributes to determine the correct context/SID to
191 * assign to the packet. Returns zero on success, negative values on failure.
192 *
193 */
194int selinux_netlbl_skbuff_getsid(struct sk_buff *skb,
195 u16 family,
196 u32 *type,
197 u32 *sid)
198{
199 int rc;
200 struct netlbl_lsm_secattr secattr;
201
202 if (!netlbl_enabled()) {
203 *type = NETLBL_NLTYPE_NONE;
204 *sid = SECSID_NULL;
205 return 0;
206 }
207
208 netlbl_secattr_init(secattr: &secattr);
209 rc = netlbl_skbuff_getattr(skb, family, secattr: &secattr);
210 if (rc == 0 && secattr.flags != NETLBL_SECATTR_NONE)
211 rc = selinux_netlbl_sidlookup_cached(skb, family,
212 secattr: &secattr, sid);
213 else
214 *sid = SECSID_NULL;
215 *type = secattr.type;
216 netlbl_secattr_destroy(secattr: &secattr);
217
218 return rc;
219}
220
221/**
222 * selinux_netlbl_skbuff_setsid - Set the NetLabel on a packet given a sid
223 * @skb: the packet
224 * @family: protocol family
225 * @sid: the SID
226 *
227 * Description
228 * Call the NetLabel mechanism to set the label of a packet using @sid.
229 * Returns zero on success, negative values on failure.
230 *
231 */
232int selinux_netlbl_skbuff_setsid(struct sk_buff *skb,
233 u16 family,
234 u32 sid)
235{
236 int rc;
237 struct netlbl_lsm_secattr secattr_storage;
238 struct netlbl_lsm_secattr *secattr = NULL;
239 struct sock *sk;
240
241 /* if this is a locally generated packet check to see if it is already
242 * being labeled by it's parent socket, if it is just exit */
243 sk = skb_to_full_sk(skb);
244 if (sk != NULL) {
245 struct sk_security_struct *sksec = selinux_sock(sock: sk);
246
247 if (sksec->nlbl_state != NLBL_REQSKB)
248 return 0;
249 secattr = selinux_netlbl_sock_getattr(sk, sid);
250 }
251 if (secattr == NULL) {
252 secattr = &secattr_storage;
253 netlbl_secattr_init(secattr);
254 rc = security_netlbl_sid_to_secattr(sid, secattr);
255 if (rc != 0)
256 goto skbuff_setsid_return;
257 }
258
259 rc = netlbl_skbuff_setattr(skb, family, secattr);
260
261skbuff_setsid_return:
262 if (secattr == &secattr_storage)
263 netlbl_secattr_destroy(secattr);
264 return rc;
265}
266
267/**
268 * selinux_netlbl_sctp_assoc_request - Label an incoming sctp association.
269 * @asoc: incoming association.
270 * @skb: the packet.
271 *
272 * Description:
273 * A new incoming connection is represented by @asoc, ......
274 * Returns zero on success, negative values on failure.
275 *
276 */
277int selinux_netlbl_sctp_assoc_request(struct sctp_association *asoc,
278 struct sk_buff *skb)
279{
280 int rc;
281 struct netlbl_lsm_secattr secattr;
282 struct sk_security_struct *sksec = selinux_sock(sock: asoc->base.sk);
283 struct sockaddr_in addr4;
284 struct sockaddr_in6 addr6;
285
286 if (asoc->base.sk->sk_family != PF_INET &&
287 asoc->base.sk->sk_family != PF_INET6)
288 return 0;
289
290 netlbl_secattr_init(secattr: &secattr);
291 rc = security_netlbl_sid_to_secattr(sid: asoc->secid, secattr: &secattr);
292 if (rc != 0)
293 goto assoc_request_return;
294
295 /* Move skb hdr address info to a struct sockaddr and then call
296 * netlbl_conn_setattr().
297 */
298 if (ip_hdr(skb)->version == 4) {
299 addr4.sin_family = AF_INET;
300 addr4.sin_addr.s_addr = ip_hdr(skb)->saddr;
301 rc = netlbl_conn_setattr(sk: asoc->base.sk, addr: (void *)&addr4, secattr: &secattr);
302 } else if (IS_ENABLED(CONFIG_IPV6) && ip_hdr(skb)->version == 6) {
303 addr6.sin6_family = AF_INET6;
304 addr6.sin6_addr = ipv6_hdr(skb)->saddr;
305 rc = netlbl_conn_setattr(sk: asoc->base.sk, addr: (void *)&addr6, secattr: &secattr);
306 } else {
307 rc = -EAFNOSUPPORT;
308 }
309
310 if (rc == 0)
311 sksec->nlbl_state = NLBL_LABELED;
312
313assoc_request_return:
314 netlbl_secattr_destroy(secattr: &secattr);
315 return rc;
316}
317
318/**
319 * selinux_netlbl_inet_conn_request - Label an incoming stream connection
320 * @req: incoming connection request socket
321 * @family: the request socket's address family
322 *
323 * Description:
324 * A new incoming connection request is represented by @req, we need to label
325 * the new request_sock here and the stack will ensure the on-the-wire label
326 * will get preserved when a full sock is created once the connection handshake
327 * is complete. Returns zero on success, negative values on failure.
328 *
329 */
330int selinux_netlbl_inet_conn_request(struct request_sock *req, u16 family)
331{
332 int rc;
333 struct netlbl_lsm_secattr secattr;
334
335 if (family != PF_INET && family != PF_INET6)
336 return 0;
337
338 netlbl_secattr_init(secattr: &secattr);
339 rc = security_netlbl_sid_to_secattr(sid: req->secid, secattr: &secattr);
340 if (rc != 0)
341 goto inet_conn_request_return;
342 rc = netlbl_req_setattr(req, secattr: &secattr);
343inet_conn_request_return:
344 netlbl_secattr_destroy(secattr: &secattr);
345 return rc;
346}
347
348/**
349 * selinux_netlbl_inet_csk_clone - Initialize the newly created sock
350 * @sk: the new sock
351 * @family: the sock's address family
352 *
353 * Description:
354 * A new connection has been established using @sk, we've already labeled the
355 * socket via the request_sock struct in selinux_netlbl_inet_conn_request() but
356 * we need to set the NetLabel state here since we now have a sock structure.
357 *
358 */
359void selinux_netlbl_inet_csk_clone(struct sock *sk, u16 family)
360{
361 struct sk_security_struct *sksec = selinux_sock(sock: sk);
362
363 if (family == PF_INET || family == PF_INET6)
364 sksec->nlbl_state = NLBL_LABELED;
365 else
366 sksec->nlbl_state = NLBL_UNSET;
367}
368
369/**
370 * selinux_netlbl_sctp_sk_clone - Copy state to the newly created sock
371 * @sk: current sock
372 * @newsk: the new sock
373 *
374 * Description:
375 * Called whenever a new socket is created by accept(2) or sctp_peeloff(3).
376 */
377void selinux_netlbl_sctp_sk_clone(struct sock *sk, struct sock *newsk)
378{
379 struct sk_security_struct *sksec = selinux_sock(sock: sk);
380 struct sk_security_struct *newsksec = selinux_sock(sock: newsk);
381
382 newsksec->nlbl_state = sksec->nlbl_state;
383}
384
385/**
386 * selinux_netlbl_socket_post_create - Label a socket using NetLabel
387 * @sk: the sock to label
388 * @family: protocol family
389 *
390 * Description:
391 * Attempt to label a socket using the NetLabel mechanism using the given
392 * SID. Returns zero values on success, negative values on failure.
393 *
394 */
395int selinux_netlbl_socket_post_create(struct sock *sk, u16 family)
396{
397 int rc;
398 struct sk_security_struct *sksec = selinux_sock(sock: sk);
399 struct netlbl_lsm_secattr *secattr;
400
401 if (family != PF_INET && family != PF_INET6)
402 return 0;
403
404 secattr = selinux_netlbl_sock_genattr(sk);
405 if (IS_ERR(ptr: secattr))
406 return PTR_ERR(ptr: secattr);
407 /* On socket creation, replacement of IP options is safe even if
408 * the caller does not hold the socket lock.
409 */
410 rc = netlbl_sock_setattr(sk, family, secattr, sk_locked: true);
411 switch (rc) {
412 case 0:
413 sksec->nlbl_state = NLBL_LABELED;
414 break;
415 case -EDESTADDRREQ:
416 sksec->nlbl_state = NLBL_REQSKB;
417 rc = 0;
418 break;
419 }
420
421 return rc;
422}
423
424/**
425 * selinux_netlbl_sock_rcv_skb - Do an inbound access check using NetLabel
426 * @sksec: the sock's sk_security_struct
427 * @skb: the packet
428 * @family: protocol family
429 * @ad: the audit data
430 *
431 * Description:
432 * Fetch the NetLabel security attributes from @skb and perform an access check
433 * against the receiving socket. Returns zero on success, negative values on
434 * error.
435 *
436 */
437int selinux_netlbl_sock_rcv_skb(struct sk_security_struct *sksec,
438 struct sk_buff *skb,
439 u16 family,
440 struct common_audit_data *ad)
441{
442 int rc;
443 u32 nlbl_sid;
444 u32 perm;
445 struct netlbl_lsm_secattr secattr;
446
447 if (!netlbl_enabled())
448 return 0;
449
450 netlbl_secattr_init(secattr: &secattr);
451 rc = netlbl_skbuff_getattr(skb, family, secattr: &secattr);
452 if (rc == 0 && secattr.flags != NETLBL_SECATTR_NONE)
453 rc = selinux_netlbl_sidlookup_cached(skb, family,
454 secattr: &secattr, sid: &nlbl_sid);
455 else
456 nlbl_sid = SECINITSID_UNLABELED;
457 netlbl_secattr_destroy(secattr: &secattr);
458 if (rc != 0)
459 return rc;
460
461 switch (sksec->sclass) {
462 case SECCLASS_UDP_SOCKET:
463 perm = UDP_SOCKET__RECVFROM;
464 break;
465 case SECCLASS_TCP_SOCKET:
466 perm = TCP_SOCKET__RECVFROM;
467 break;
468 default:
469 perm = RAWIP_SOCKET__RECVFROM;
470 }
471
472 rc = avc_has_perm(ssid: sksec->sid, tsid: nlbl_sid, tclass: sksec->sclass, requested: perm, auditdata: ad);
473 if (rc == 0)
474 return 0;
475
476 if (nlbl_sid != SECINITSID_UNLABELED)
477 netlbl_skbuff_err(skb, family, error: rc, gateway: 0);
478 return rc;
479}
480
481/**
482 * selinux_netlbl_option - Is this a NetLabel option
483 * @level: the socket level or protocol
484 * @optname: the socket option name
485 *
486 * Description:
487 * Returns true if @level and @optname refer to a NetLabel option.
488 * Helper for selinux_netlbl_socket_setsockopt().
489 */
490static inline int selinux_netlbl_option(int level, int optname)
491{
492 return (level == IPPROTO_IP && optname == IP_OPTIONS) ||
493 (level == IPPROTO_IPV6 && optname == IPV6_HOPOPTS);
494}
495
496/**
497 * selinux_netlbl_socket_setsockopt - Do not allow users to remove a NetLabel
498 * @sock: the socket
499 * @level: the socket level or protocol
500 * @optname: the socket option name
501 *
502 * Description:
503 * Check the setsockopt() call and if the user is trying to replace the IP
504 * options on a socket and a NetLabel is in place for the socket deny the
505 * access; otherwise allow the access. Returns zero when the access is
506 * allowed, -EACCES when denied, and other negative values on error.
507 *
508 */
509int selinux_netlbl_socket_setsockopt(struct socket *sock,
510 int level,
511 int optname)
512{
513 int rc = 0;
514 struct sock *sk = sock->sk;
515 struct sk_security_struct *sksec = selinux_sock(sock: sk);
516 struct netlbl_lsm_secattr secattr;
517
518 if (selinux_netlbl_option(level, optname) &&
519 (sksec->nlbl_state == NLBL_LABELED ||
520 sksec->nlbl_state == NLBL_CONNLABELED)) {
521 netlbl_secattr_init(secattr: &secattr);
522 lock_sock(sk);
523 /* call the netlabel function directly as we want to see the
524 * on-the-wire label that is assigned via the socket's options
525 * and not the cached netlabel/lsm attributes */
526 rc = netlbl_sock_getattr(sk, secattr: &secattr);
527 release_sock(sk);
528 if (rc == 0)
529 rc = -EACCES;
530 else if (rc == -ENOMSG)
531 rc = 0;
532 netlbl_secattr_destroy(secattr: &secattr);
533 }
534
535 return rc;
536}
537
538/**
539 * selinux_netlbl_socket_connect_helper - Help label a client-side socket on
540 * connect
541 * @sk: the socket to label
542 * @addr: the destination address
543 *
544 * Description:
545 * Attempt to label a connected socket with NetLabel using the given address.
546 * Returns zero values on success, negative values on failure.
547 *
548 */
549static int selinux_netlbl_socket_connect_helper(struct sock *sk,
550 struct sockaddr *addr)
551{
552 int rc;
553 struct sk_security_struct *sksec = selinux_sock(sock: sk);
554 struct netlbl_lsm_secattr *secattr;
555
556 /* connected sockets are allowed to disconnect when the address family
557 * is set to AF_UNSPEC, if that is what is happening we want to reset
558 * the socket */
559 if (addr->sa_family == AF_UNSPEC) {
560 netlbl_sock_delattr(sk);
561 sksec->nlbl_state = NLBL_REQSKB;
562 rc = 0;
563 return rc;
564 }
565 secattr = selinux_netlbl_sock_genattr(sk);
566 if (IS_ERR(ptr: secattr))
567 return PTR_ERR(ptr: secattr);
568
569 rc = netlbl_conn_setattr(sk, addr, secattr);
570 if (rc == 0)
571 sksec->nlbl_state = NLBL_CONNLABELED;
572
573 return rc;
574}
575
576/**
577 * selinux_netlbl_socket_connect_locked - Label a client-side socket on
578 * connect
579 * @sk: the socket to label
580 * @addr: the destination address
581 *
582 * Description:
583 * Attempt to label a connected socket that already has the socket locked
584 * with NetLabel using the given address.
585 * Returns zero values on success, negative values on failure.
586 *
587 */
588int selinux_netlbl_socket_connect_locked(struct sock *sk,
589 struct sockaddr *addr)
590{
591 struct sk_security_struct *sksec = selinux_sock(sock: sk);
592
593 if (sksec->nlbl_state != NLBL_REQSKB &&
594 sksec->nlbl_state != NLBL_CONNLABELED)
595 return 0;
596
597 return selinux_netlbl_socket_connect_helper(sk, addr);
598}
599
600/**
601 * selinux_netlbl_socket_connect - Label a client-side socket on connect
602 * @sk: the socket to label
603 * @addr: the destination address
604 *
605 * Description:
606 * Attempt to label a connected socket with NetLabel using the given address.
607 * Returns zero values on success, negative values on failure.
608 *
609 */
610int selinux_netlbl_socket_connect(struct sock *sk, struct sockaddr *addr)
611{
612 int rc;
613
614 lock_sock(sk);
615 rc = selinux_netlbl_socket_connect_locked(sk, addr);
616 release_sock(sk);
617
618 return rc;
619}
620

source code of linux/security/selinux/netlabel.c