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git.proxmox.com Git - mirror_ubuntu-focal-kernel.git/blob - security/selinux/xfrm.c
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/kernel.h>
35 #include <linux/init.h>
36 #include <linux/security.h>
37 #include <linux/types.h>
38 #include <linux/netfilter.h>
39 #include <linux/netfilter_ipv4.h>
40 #include <linux/netfilter_ipv6.h>
42 #include <linux/tcp.h>
43 #include <linux/skbuff.h>
44 #include <linux/xfrm.h>
46 #include <net/checksum.h>
48 #include <asm/semaphore.h>
56 * Returns true if an LSM/SELinux context
58 static inline int selinux_authorizable_ctx(struct xfrm_sec_ctx
*ctx
)
61 (ctx
->ctx_doi
== XFRM_SC_DOI_LSM
) &&
62 (ctx
->ctx_alg
== XFRM_SC_ALG_SELINUX
));
66 * Returns true if the xfrm contains a security blob for SELinux
68 static inline int selinux_authorizable_xfrm(struct xfrm_state
*x
)
70 return selinux_authorizable_ctx(x
->security
);
74 * LSM hook implementation that authorizes that a flow can use
77 int selinux_xfrm_policy_lookup(struct xfrm_policy
*xp
, u32 fl_secid
, u8 dir
)
81 struct xfrm_sec_ctx
*ctx
;
83 /* Context sid is either set to label or ANY_ASSOC */
84 if ((ctx
= xp
->security
)) {
85 if (!selinux_authorizable_ctx(ctx
))
88 sel_sid
= ctx
->ctx_sid
;
92 * All flows should be treated as polmatch'ing an
93 * otherwise applicable "non-labeled" policy. This
94 * would prevent inadvertent "leaks".
98 rc
= avc_has_perm(fl_secid
, sel_sid
, SECCLASS_ASSOCIATION
,
99 ASSOCIATION__POLMATCH
,
109 * LSM hook implementation that authorizes that a state matches
110 * the given policy, flow combo.
113 int selinux_xfrm_state_pol_flow_match(struct xfrm_state
*x
, struct xfrm_policy
*xp
,
121 /* unlabeled policy and labeled SA can't match */
124 /* unlabeled policy and unlabeled SA match all flows */
128 /* unlabeled SA and labeled policy can't match */
131 if (!selinux_authorizable_xfrm(x
))
132 /* Not a SELinux-labeled SA */
135 state_sid
= x
->security
->ctx_sid
;
137 if (fl
->secid
!= state_sid
)
140 rc
= avc_has_perm(fl
->secid
, state_sid
, SECCLASS_ASSOCIATION
,
145 * We don't need a separate SA Vs. policy polmatch check
146 * since the SA is now of the same label as the flow and
147 * a flow Vs. policy polmatch check had already happened
148 * in selinux_xfrm_policy_lookup() above.
155 * LSM hook implementation that checks and/or returns the xfrm sid for the
159 int selinux_xfrm_decode_session(struct sk_buff
*skb
, u32
*sid
, int ckall
)
172 for (i
= sp
->len
-1; i
>= 0; i
--) {
173 struct xfrm_state
*x
= sp
->xvec
[i
];
174 if (selinux_authorizable_xfrm(x
)) {
175 struct xfrm_sec_ctx
*ctx
= x
->security
;
184 else if (*sid
!= ctx
->ctx_sid
)
194 * Security blob allocation for xfrm_policy and xfrm_state
195 * CTX does not have a meaningful value on input
197 static int selinux_xfrm_sec_ctx_alloc(struct xfrm_sec_ctx
**ctxp
,
198 struct xfrm_user_sec_ctx
*uctx
, u32 sid
)
201 struct task_security_struct
*tsec
= current
->security
;
202 struct xfrm_sec_ctx
*ctx
= NULL
;
203 char *ctx_str
= NULL
;
211 if (uctx
->ctx_doi
!= XFRM_SC_ALG_SELINUX
)
214 if (uctx
->ctx_len
>= PAGE_SIZE
)
217 *ctxp
= ctx
= kmalloc(sizeof(*ctx
) +
224 ctx
->ctx_doi
= uctx
->ctx_doi
;
225 ctx
->ctx_len
= uctx
->ctx_len
;
226 ctx
->ctx_alg
= uctx
->ctx_alg
;
231 ctx
->ctx_str
[ctx
->ctx_len
] = 0;
232 rc
= security_context_to_sid(ctx
->ctx_str
,
240 * Does the subject have permission to set security context?
242 rc
= avc_has_perm(tsec
->sid
, ctx
->ctx_sid
,
243 SECCLASS_ASSOCIATION
,
244 ASSOCIATION__SETCONTEXT
, NULL
);
251 rc
= security_sid_to_context(sid
, &ctx_str
, &str_len
);
255 *ctxp
= ctx
= kmalloc(sizeof(*ctx
) +
264 ctx
->ctx_doi
= XFRM_SC_DOI_LSM
;
265 ctx
->ctx_alg
= XFRM_SC_ALG_SELINUX
;
267 ctx
->ctx_len
= str_len
;
283 * LSM hook implementation that allocs and transfers uctx spec to
286 int selinux_xfrm_policy_alloc(struct xfrm_policy
*xp
,
287 struct xfrm_user_sec_ctx
*uctx
)
294 err
= selinux_xfrm_sec_ctx_alloc(&xp
->security
, uctx
, 0);
300 * LSM hook implementation that copies security data structure from old to
301 * new for policy cloning.
303 int selinux_xfrm_policy_clone(struct xfrm_policy
*old
, struct xfrm_policy
*new)
305 struct xfrm_sec_ctx
*old_ctx
, *new_ctx
;
307 old_ctx
= old
->security
;
310 new_ctx
= new->security
= kmalloc(sizeof(*new_ctx
) +
317 memcpy(new_ctx
, old_ctx
, sizeof(*new_ctx
));
318 memcpy(new_ctx
->ctx_str
, old_ctx
->ctx_str
, new_ctx
->ctx_len
);
324 * LSM hook implementation that frees xfrm_policy security information.
326 void selinux_xfrm_policy_free(struct xfrm_policy
*xp
)
328 struct xfrm_sec_ctx
*ctx
= xp
->security
;
334 * LSM hook implementation that authorizes deletion of labeled policies.
336 int selinux_xfrm_policy_delete(struct xfrm_policy
*xp
)
338 struct task_security_struct
*tsec
= current
->security
;
339 struct xfrm_sec_ctx
*ctx
= xp
->security
;
343 rc
= avc_has_perm(tsec
->sid
, ctx
->ctx_sid
,
344 SECCLASS_ASSOCIATION
,
345 ASSOCIATION__SETCONTEXT
, NULL
);
351 * LSM hook implementation that allocs and transfers sec_ctx spec to
354 int selinux_xfrm_state_alloc(struct xfrm_state
*x
, struct xfrm_user_sec_ctx
*uctx
,
361 err
= selinux_xfrm_sec_ctx_alloc(&x
->security
, uctx
, secid
);
366 * LSM hook implementation that frees xfrm_state security information.
368 void selinux_xfrm_state_free(struct xfrm_state
*x
)
370 struct xfrm_sec_ctx
*ctx
= x
->security
;
376 * LSM hook implementation that authorizes deletion of labeled SAs.
378 int selinux_xfrm_state_delete(struct xfrm_state
*x
)
380 struct task_security_struct
*tsec
= current
->security
;
381 struct xfrm_sec_ctx
*ctx
= x
->security
;
385 rc
= avc_has_perm(tsec
->sid
, ctx
->ctx_sid
,
386 SECCLASS_ASSOCIATION
,
387 ASSOCIATION__SETCONTEXT
, NULL
);
393 * LSM hook that controls access to unlabelled packets. If
394 * a xfrm_state is authorizable (defined by macro) then it was
395 * already authorized by the IPSec process. If not, then
396 * we need to check for unlabelled access since this may not have
397 * gone thru the IPSec process.
399 int selinux_xfrm_sock_rcv_skb(u32 isec_sid
, struct sk_buff
*skb
,
400 struct avc_audit_data
*ad
)
404 u32 sel_sid
= SECINITSID_UNLABELED
;
409 for (i
= 0; i
< sp
->len
; i
++) {
410 struct xfrm_state
*x
= sp
->xvec
[i
];
412 if (x
&& selinux_authorizable_xfrm(x
)) {
413 struct xfrm_sec_ctx
*ctx
= x
->security
;
414 sel_sid
= ctx
->ctx_sid
;
421 * This check even when there's no association involved is
422 * intended, according to Trent Jaeger, to make sure a
423 * process can't engage in non-ipsec communication unless
424 * explicitly allowed by policy.
427 rc
= avc_has_perm(isec_sid
, sel_sid
, SECCLASS_ASSOCIATION
,
428 ASSOCIATION__RECVFROM
, ad
);
434 * POSTROUTE_LAST hook's XFRM processing:
435 * If we have no security association, then we need to determine
436 * whether the socket is allowed to send to an unlabelled destination.
437 * If we do have a authorizable security association, then it has already been
438 * checked in the selinux_xfrm_state_pol_flow_match hook above.
440 int selinux_xfrm_postroute_last(u32 isec_sid
, struct sk_buff
*skb
,
441 struct avc_audit_data
*ad
, u8 proto
)
443 struct dst_entry
*dst
;
449 struct dst_entry
*dst_test
;
451 for (dst_test
= dst
; dst_test
!= NULL
;
452 dst_test
= dst_test
->child
) {
453 struct xfrm_state
*x
= dst_test
->xfrm
;
455 if (x
&& selinux_authorizable_xfrm(x
))
465 * We should have already seen this packet once before
466 * it underwent xfrm(s). No need to subject it to the
475 * This check even when there's no association involved is
476 * intended, according to Trent Jaeger, to make sure a
477 * process can't engage in non-ipsec communication unless
478 * explicitly allowed by policy.
481 rc
= avc_has_perm(isec_sid
, SECINITSID_UNLABELED
, SECCLASS_ASSOCIATION
,
482 ASSOCIATION__SENDTO
, ad
);