2 * NSA Security-Enhanced Linux (SELinux) security module
4 * This file contains the SELinux XFRM hook function implementations.
6 * Authors: Serge Hallyn <sergeh@us.ibm.com>
7 * Trent Jaeger <jaegert@us.ibm.com>
9 * Updated: Venkat Yekkirala <vyekkirala@TrustedCS.com>
11 * Granular IPSec Associations for use in MLS environments.
13 * Copyright (C) 2005 International Business Machines Corporation
14 * Copyright (C) 2006 Trusted Computer Solutions, Inc.
16 * This program is free software; you can redistribute it and/or modify
17 * it under the terms of the GNU General Public License version 2,
18 * as published by the Free Software Foundation.
24 * 1. Make sure to enable the following options in your kernel config:
26 * CONFIG_SECURITY_NETWORK=y
27 * CONFIG_SECURITY_NETWORK_XFRM=y
28 * CONFIG_SECURITY_SELINUX=m/y
30 * 1. Caching packets, so they are not dropped during negotiation
31 * 2. Emulating a reasonable SO_PEERSEC across machines
32 * 3. Testing addition of sk_policy's with security context via setsockopt
34 #include <linux/module.h>
35 #include <linux/kernel.h>
36 #include <linux/init.h>
37 #include <linux/security.h>
38 #include <linux/types.h>
39 #include <linux/netfilter.h>
40 #include <linux/netfilter_ipv4.h>
41 #include <linux/netfilter_ipv6.h>
43 #include <linux/tcp.h>
44 #include <linux/skbuff.h>
45 #include <linux/xfrm.h>
47 #include <net/checksum.h>
49 #include <asm/semaphore.h>
57 * Returns true if an LSM/SELinux context
59 static inline int selinux_authorizable_ctx(struct xfrm_sec_ctx
*ctx
)
62 (ctx
->ctx_doi
== XFRM_SC_DOI_LSM
) &&
63 (ctx
->ctx_alg
== XFRM_SC_ALG_SELINUX
));
67 * Returns true if the xfrm contains a security blob for SELinux
69 static inline int selinux_authorizable_xfrm(struct xfrm_state
*x
)
71 return selinux_authorizable_ctx(x
->security
);
75 * LSM hook implementation that authorizes that a flow can use
78 int selinux_xfrm_policy_lookup(struct xfrm_policy
*xp
, u32 fl_secid
, u8 dir
)
81 u32 sel_sid
= SECINITSID_UNLABELED
;
82 struct xfrm_sec_ctx
*ctx
;
84 /* Context sid is either set to label or ANY_ASSOC */
85 if ((ctx
= xp
->security
)) {
86 if (!selinux_authorizable_ctx(ctx
))
89 sel_sid
= ctx
->ctx_sid
;
92 rc
= avc_has_perm(fl_secid
, sel_sid
, SECCLASS_ASSOCIATION
,
93 ASSOCIATION__POLMATCH
,
100 * LSM hook implementation that authorizes that a state matches
101 * the given policy, flow combo.
104 int selinux_xfrm_state_pol_flow_match(struct xfrm_state
*x
, struct xfrm_policy
*xp
,
112 state_sid
= x
->security
->ctx_sid
;
114 state_sid
= SECINITSID_UNLABELED
;
117 pol_sid
= xp
->security
->ctx_sid
;
119 pol_sid
= SECINITSID_UNLABELED
;
121 err
= avc_has_perm(state_sid
, pol_sid
, SECCLASS_ASSOCIATION
,
122 ASSOCIATION__POLMATCH
,
128 return selinux_xfrm_flow_state_match(fl
, x
);
132 * LSM hook implementation that authorizes that a particular outgoing flow
133 * can use a given security association.
136 int selinux_xfrm_flow_state_match(struct flowi
*fl
, struct xfrm_state
*xfrm
)
139 u32 sel_sid
= SECINITSID_UNLABELED
;
140 struct xfrm_sec_ctx
*ctx
;
142 /* Context sid is either set to label or ANY_ASSOC */
143 if ((ctx
= xfrm
->security
)) {
144 if (!selinux_authorizable_ctx(ctx
))
147 sel_sid
= ctx
->ctx_sid
;
150 rc
= avc_has_perm(fl
->secid
, sel_sid
, SECCLASS_ASSOCIATION
,
158 * LSM hook implementation that determines the sid for the session.
161 int selinux_xfrm_decode_session(struct sk_buff
*skb
, u32
*sid
, int ckall
)
174 for (i
= sp
->len
-1; i
>= 0; i
--) {
175 struct xfrm_state
*x
= sp
->xvec
[i
];
176 if (selinux_authorizable_xfrm(x
)) {
177 struct xfrm_sec_ctx
*ctx
= x
->security
;
186 else if (*sid
!= ctx
->ctx_sid
)
196 * Security blob allocation for xfrm_policy and xfrm_state
197 * CTX does not have a meaningful value on input
199 static int selinux_xfrm_sec_ctx_alloc(struct xfrm_sec_ctx
**ctxp
,
200 struct xfrm_user_sec_ctx
*uctx
, struct xfrm_sec_ctx
*pol
, u32 sid
)
203 struct task_security_struct
*tsec
= current
->security
;
204 struct xfrm_sec_ctx
*ctx
= NULL
;
205 char *ctx_str
= NULL
;
216 if (uctx
->ctx_doi
!= XFRM_SC_ALG_SELINUX
)
219 if (uctx
->ctx_len
>= PAGE_SIZE
)
222 *ctxp
= ctx
= kmalloc(sizeof(*ctx
) +
229 ctx
->ctx_doi
= uctx
->ctx_doi
;
230 ctx
->ctx_len
= uctx
->ctx_len
;
231 ctx
->ctx_alg
= uctx
->ctx_alg
;
236 rc
= security_context_to_sid(ctx
->ctx_str
,
244 * Does the subject have permission to set security context?
246 rc
= avc_has_perm(tsec
->sid
, ctx
->ctx_sid
,
247 SECCLASS_ASSOCIATION
,
248 ASSOCIATION__SETCONTEXT
, NULL
);
256 rc
= security_sid_mls_copy(pol
->ctx_sid
, sid
, &ctx_sid
);
260 rc
= security_sid_to_context(ctx_sid
, &ctx_str
, &str_len
);
264 *ctxp
= ctx
= kmalloc(sizeof(*ctx
) +
274 ctx
->ctx_doi
= XFRM_SC_DOI_LSM
;
275 ctx
->ctx_alg
= XFRM_SC_ALG_SELINUX
;
276 ctx
->ctx_sid
= ctx_sid
;
277 ctx
->ctx_len
= str_len
;
293 * LSM hook implementation that allocs and transfers uctx spec to
296 int selinux_xfrm_policy_alloc(struct xfrm_policy
*xp
, struct xfrm_user_sec_ctx
*uctx
)
302 err
= selinux_xfrm_sec_ctx_alloc(&xp
->security
, uctx
, NULL
, 0);
308 * LSM hook implementation that copies security data structure from old to
309 * new for policy cloning.
311 int selinux_xfrm_policy_clone(struct xfrm_policy
*old
, struct xfrm_policy
*new)
313 struct xfrm_sec_ctx
*old_ctx
, *new_ctx
;
315 old_ctx
= old
->security
;
318 new_ctx
= new->security
= kmalloc(sizeof(*new_ctx
) +
325 memcpy(new_ctx
, old_ctx
, sizeof(*new_ctx
));
326 memcpy(new_ctx
->ctx_str
, old_ctx
->ctx_str
, new_ctx
->ctx_len
);
332 * LSM hook implementation that frees xfrm_policy security information.
334 void selinux_xfrm_policy_free(struct xfrm_policy
*xp
)
336 struct xfrm_sec_ctx
*ctx
= xp
->security
;
342 * LSM hook implementation that authorizes deletion of labeled policies.
344 int selinux_xfrm_policy_delete(struct xfrm_policy
*xp
)
346 struct task_security_struct
*tsec
= current
->security
;
347 struct xfrm_sec_ctx
*ctx
= xp
->security
;
351 rc
= avc_has_perm(tsec
->sid
, ctx
->ctx_sid
,
352 SECCLASS_ASSOCIATION
,
353 ASSOCIATION__SETCONTEXT
, NULL
);
359 * LSM hook implementation that allocs and transfers sec_ctx spec to
362 int selinux_xfrm_state_alloc(struct xfrm_state
*x
, struct xfrm_user_sec_ctx
*uctx
,
363 struct xfrm_sec_ctx
*pol
, u32 secid
)
369 err
= selinux_xfrm_sec_ctx_alloc(&x
->security
, uctx
, pol
, secid
);
374 * LSM hook implementation that frees xfrm_state security information.
376 void selinux_xfrm_state_free(struct xfrm_state
*x
)
378 struct xfrm_sec_ctx
*ctx
= x
->security
;
384 * SELinux internal function to retrieve the context of a connected
385 * (sk->sk_state == TCP_ESTABLISHED) TCP socket based on its security
386 * association used to connect to the remote socket.
388 * Retrieve via getsockopt SO_PEERSEC.
390 u32
selinux_socket_getpeer_stream(struct sock
*sk
)
392 struct dst_entry
*dst
, *dst_test
;
393 u32 peer_sid
= SECSID_NULL
;
395 if (sk
->sk_state
!= TCP_ESTABLISHED
)
398 dst
= sk_dst_get(sk
);
402 for (dst_test
= dst
; dst_test
!= 0;
403 dst_test
= dst_test
->child
) {
404 struct xfrm_state
*x
= dst_test
->xfrm
;
406 if (x
&& selinux_authorizable_xfrm(x
)) {
407 struct xfrm_sec_ctx
*ctx
= x
->security
;
408 peer_sid
= ctx
->ctx_sid
;
419 * SELinux internal function to retrieve the context of a UDP packet
420 * based on its security association used to connect to the remote socket.
422 * Retrieve via setsockopt IP_PASSSEC and recvmsg with control message
425 u32
selinux_socket_getpeer_dgram(struct sk_buff
*skb
)
432 if (skb
->sk
->sk_protocol
!= IPPROTO_UDP
)
439 for (i
= sp
->len
-1; i
>= 0; i
--) {
440 struct xfrm_state
*x
= sp
->xvec
[i
];
441 if (selinux_authorizable_xfrm(x
)) {
442 struct xfrm_sec_ctx
*ctx
= x
->security
;
452 * LSM hook implementation that authorizes deletion of labeled SAs.
454 int selinux_xfrm_state_delete(struct xfrm_state
*x
)
456 struct task_security_struct
*tsec
= current
->security
;
457 struct xfrm_sec_ctx
*ctx
= x
->security
;
461 rc
= avc_has_perm(tsec
->sid
, ctx
->ctx_sid
,
462 SECCLASS_ASSOCIATION
,
463 ASSOCIATION__SETCONTEXT
, NULL
);
469 * LSM hook that controls access to unlabelled packets. If
470 * a xfrm_state is authorizable (defined by macro) then it was
471 * already authorized by the IPSec process. If not, then
472 * we need to check for unlabelled access since this may not have
473 * gone thru the IPSec process.
475 int selinux_xfrm_sock_rcv_skb(u32 isec_sid
, struct sk_buff
*skb
,
476 struct avc_audit_data
*ad
)
480 u32 sel_sid
= SECINITSID_UNLABELED
;
485 for (i
= 0; i
< sp
->len
; i
++) {
486 struct xfrm_state
*x
= sp
->xvec
[i
];
488 if (x
&& selinux_authorizable_xfrm(x
)) {
489 struct xfrm_sec_ctx
*ctx
= x
->security
;
490 sel_sid
= ctx
->ctx_sid
;
496 rc
= avc_has_perm(isec_sid
, sel_sid
, SECCLASS_ASSOCIATION
,
497 ASSOCIATION__RECVFROM
, ad
);
503 * POSTROUTE_LAST hook's XFRM processing:
504 * If we have no security association, then we need to determine
505 * whether the socket is allowed to send to an unlabelled destination.
506 * If we do have a authorizable security association, then it has already been
507 * checked in xfrm_policy_lookup hook.
509 int selinux_xfrm_postroute_last(u32 isec_sid
, struct sk_buff
*skb
,
510 struct avc_audit_data
*ad
)
512 struct dst_entry
*dst
;
518 struct dst_entry
*dst_test
;
520 for (dst_test
= dst
; dst_test
!= 0;
521 dst_test
= dst_test
->child
) {
522 struct xfrm_state
*x
= dst_test
->xfrm
;
524 if (x
&& selinux_authorizable_xfrm(x
))
529 rc
= avc_has_perm(isec_sid
, SECINITSID_UNLABELED
, SECCLASS_ASSOCIATION
,
530 ASSOCIATION__SENDTO
, ad
);
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