blob: 72b18452e1a12035f20e4269e0ed6d4474e135f2 [file] [log] [blame]
Trent Jaegerd28d1e02005-12-13 23:12:40 -08001/*
2 * NSA Security-Enhanced Linux (SELinux) security module
3 *
4 * This file contains the SELinux XFRM hook function implementations.
5 *
6 * Authors: Serge Hallyn <sergeh@us.ibm.com>
7 * Trent Jaeger <jaegert@us.ibm.com>
8 *
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -07009 * Updated: Venkat Yekkirala <vyekkirala@TrustedCS.com>
10 *
11 * Granular IPSec Associations for use in MLS environments.
12 *
Trent Jaegerd28d1e02005-12-13 23:12:40 -080013 * Copyright (C) 2005 International Business Machines Corporation
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -070014 * Copyright (C) 2006 Trusted Computer Solutions, Inc.
Trent Jaegerd28d1e02005-12-13 23:12:40 -080015 *
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.
19 */
20
21/*
22 * USAGE:
23 * NOTES:
24 * 1. Make sure to enable the following options in your kernel config:
25 * CONFIG_SECURITY=y
26 * CONFIG_SECURITY_NETWORK=y
27 * CONFIG_SECURITY_NETWORK_XFRM=y
28 * CONFIG_SECURITY_SELINUX=m/y
29 * ISSUES:
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
33 */
Trent Jaegerd28d1e02005-12-13 23:12:40 -080034#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>
41#include <linux/ip.h>
42#include <linux/tcp.h>
43#include <linux/skbuff.h>
44#include <linux/xfrm.h>
45#include <net/xfrm.h>
46#include <net/checksum.h>
47#include <net/udp.h>
Paul Moored621d352008-01-29 08:43:36 -050048#include <asm/atomic.h>
Trent Jaegerd28d1e02005-12-13 23:12:40 -080049
50#include "avc.h"
51#include "objsec.h"
52#include "xfrm.h"
53
Paul Moored621d352008-01-29 08:43:36 -050054/* Labeled XFRM instance counter */
55atomic_t selinux_xfrm_refcount = ATOMIC_INIT(0);
Trent Jaegerd28d1e02005-12-13 23:12:40 -080056
57/*
58 * Returns true if an LSM/SELinux context
59 */
60static inline int selinux_authorizable_ctx(struct xfrm_sec_ctx *ctx)
61{
62 return (ctx &&
63 (ctx->ctx_doi == XFRM_SC_DOI_LSM) &&
64 (ctx->ctx_alg == XFRM_SC_ALG_SELINUX));
65}
66
67/*
68 * Returns true if the xfrm contains a security blob for SELinux
69 */
70static inline int selinux_authorizable_xfrm(struct xfrm_state *x)
71{
72 return selinux_authorizable_ctx(x->security);
73}
74
75/*
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -070076 * LSM hook implementation that authorizes that a flow can use
77 * a xfrm policy rule.
Trent Jaegerd28d1e02005-12-13 23:12:40 -080078 */
Paul Moore03e1ad72008-04-12 19:07:52 -070079int selinux_xfrm_policy_lookup(struct xfrm_sec_ctx *ctx, u32 fl_secid, u8 dir)
Trent Jaegerd28d1e02005-12-13 23:12:40 -080080{
Venkat Yekkirala5b368e62006-10-05 15:42:18 -050081 int rc;
82 u32 sel_sid;
Trent Jaegerd28d1e02005-12-13 23:12:40 -080083
84 /* Context sid is either set to label or ANY_ASSOC */
Paul Moore03e1ad72008-04-12 19:07:52 -070085 if (ctx) {
Trent Jaegerd28d1e02005-12-13 23:12:40 -080086 if (!selinux_authorizable_ctx(ctx))
87 return -EINVAL;
88
89 sel_sid = ctx->ctx_sid;
Paul Moore03e1ad72008-04-12 19:07:52 -070090 } else
Venkat Yekkirala5b368e62006-10-05 15:42:18 -050091 /*
92 * All flows should be treated as polmatch'ing an
93 * otherwise applicable "non-labeled" policy. This
94 * would prevent inadvertent "leaks".
95 */
96 return 0;
Trent Jaegerd28d1e02005-12-13 23:12:40 -080097
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -070098 rc = avc_has_perm(fl_secid, sel_sid, SECCLASS_ASSOCIATION,
99 ASSOCIATION__POLMATCH,
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800100 NULL);
101
Venkat Yekkirala5b368e62006-10-05 15:42:18 -0500102 if (rc == -EACCES)
Paul Moore03e1ad72008-04-12 19:07:52 -0700103 return -ESRCH;
Venkat Yekkirala5b368e62006-10-05 15:42:18 -0500104
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800105 return rc;
106}
107
108/*
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700109 * LSM hook implementation that authorizes that a state matches
110 * the given policy, flow combo.
111 */
112
113int selinux_xfrm_state_pol_flow_match(struct xfrm_state *x, struct xfrm_policy *xp,
114 struct flowi *fl)
115{
116 u32 state_sid;
Venkat Yekkirala67f83cb2006-11-08 17:04:26 -0600117 int rc;
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700118
Venkat Yekkirala67f83cb2006-11-08 17:04:26 -0600119 if (!xp->security)
Venkat Yekkirala5b368e62006-10-05 15:42:18 -0500120 if (x->security)
121 /* unlabeled policy and labeled SA can't match */
122 return 0;
123 else
124 /* unlabeled policy and unlabeled SA match all flows */
125 return 1;
Venkat Yekkirala67f83cb2006-11-08 17:04:26 -0600126 else
127 if (!x->security)
128 /* unlabeled SA and labeled policy can't match */
129 return 0;
130 else
131 if (!selinux_authorizable_xfrm(x))
132 /* Not a SELinux-labeled SA */
133 return 0;
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700134
Venkat Yekkirala67f83cb2006-11-08 17:04:26 -0600135 state_sid = x->security->ctx_sid;
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700136
Venkat Yekkirala67f83cb2006-11-08 17:04:26 -0600137 if (fl->secid != state_sid)
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700138 return 0;
139
Venkat Yekkirala67f83cb2006-11-08 17:04:26 -0600140 rc = avc_has_perm(fl->secid, state_sid, SECCLASS_ASSOCIATION,
Venkat Yekkirala5b368e62006-10-05 15:42:18 -0500141 ASSOCIATION__SENDTO,
142 NULL)? 0:1;
143
Venkat Yekkirala67f83cb2006-11-08 17:04:26 -0600144 /*
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.
149 */
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700150
151 return rc;
152}
153
154/*
Venkat Yekkirala6b877692006-11-08 17:04:09 -0600155 * LSM hook implementation that checks and/or returns the xfrm sid for the
156 * incoming packet.
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700157 */
158
Venkat Yekkiralabeb8d132006-08-04 23:12:42 -0700159int selinux_xfrm_decode_session(struct sk_buff *skb, u32 *sid, int ckall)
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700160{
161 struct sec_path *sp;
162
Venkat Yekkiralabeb8d132006-08-04 23:12:42 -0700163 *sid = SECSID_NULL;
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700164
165 if (skb == NULL)
166 return 0;
167
168 sp = skb->sp;
169 if (sp) {
170 int i, sid_set = 0;
171
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;
176
177 if (!sid_set) {
Venkat Yekkiralabeb8d132006-08-04 23:12:42 -0700178 *sid = ctx->ctx_sid;
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700179 sid_set = 1;
Venkat Yekkiralabeb8d132006-08-04 23:12:42 -0700180
181 if (!ckall)
182 break;
Eric Paris3c1c88a2008-04-18 17:38:27 -0400183 } else if (*sid != ctx->ctx_sid)
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700184 return -EINVAL;
185 }
186 }
187 }
188
189 return 0;
190}
191
192/*
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800193 * Security blob allocation for xfrm_policy and xfrm_state
194 * CTX does not have a meaningful value on input
195 */
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700196static int selinux_xfrm_sec_ctx_alloc(struct xfrm_sec_ctx **ctxp,
Venkat Yekkiralac1a856c2006-11-08 17:03:44 -0600197 struct xfrm_user_sec_ctx *uctx, u32 sid)
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800198{
199 int rc = 0;
David Howells86a264a2008-11-14 10:39:18 +1100200 const struct task_security_struct *tsec = current_security();
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700201 struct xfrm_sec_ctx *ctx = NULL;
202 char *ctx_str = NULL;
203 u32 str_len;
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700204
Venkat Yekkiralac1a856c2006-11-08 17:03:44 -0600205 BUG_ON(uctx && sid);
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700206
Venkat Yekkiralacb969f02006-07-24 23:32:20 -0700207 if (!uctx)
208 goto not_from_user;
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700209
210 if (uctx->ctx_doi != XFRM_SC_ALG_SELINUX)
211 return -EINVAL;
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800212
Stephen Rothwell57002bf2007-10-31 16:47:19 +1100213 str_len = uctx->ctx_len;
214 if (str_len >= PAGE_SIZE)
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800215 return -ENOMEM;
216
217 *ctxp = ctx = kmalloc(sizeof(*ctx) +
Stephen Rothwell57002bf2007-10-31 16:47:19 +1100218 str_len + 1,
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800219 GFP_KERNEL);
220
221 if (!ctx)
222 return -ENOMEM;
223
224 ctx->ctx_doi = uctx->ctx_doi;
Stephen Rothwell57002bf2007-10-31 16:47:19 +1100225 ctx->ctx_len = str_len;
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800226 ctx->ctx_alg = uctx->ctx_alg;
227
228 memcpy(ctx->ctx_str,
229 uctx+1,
Stephen Rothwell57002bf2007-10-31 16:47:19 +1100230 str_len);
231 ctx->ctx_str[str_len] = 0;
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800232 rc = security_context_to_sid(ctx->ctx_str,
Stephen Rothwell57002bf2007-10-31 16:47:19 +1100233 str_len,
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800234 &ctx->ctx_sid);
235
236 if (rc)
237 goto out;
238
239 /*
Catherine Zhangc8c05a82006-06-08 23:39:49 -0700240 * Does the subject have permission to set security context?
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800241 */
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800242 rc = avc_has_perm(tsec->sid, ctx->ctx_sid,
243 SECCLASS_ASSOCIATION,
Trent Jaeger5f8ac642006-01-06 13:22:39 -0800244 ASSOCIATION__SETCONTEXT, NULL);
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800245 if (rc)
246 goto out;
247
248 return rc;
249
Venkat Yekkiralacb969f02006-07-24 23:32:20 -0700250not_from_user:
Venkat Yekkiralac1a856c2006-11-08 17:03:44 -0600251 rc = security_sid_to_context(sid, &ctx_str, &str_len);
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700252 if (rc)
253 goto out;
254
255 *ctxp = ctx = kmalloc(sizeof(*ctx) +
256 str_len,
257 GFP_ATOMIC);
258
259 if (!ctx) {
260 rc = -ENOMEM;
261 goto out;
262 }
263
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700264 ctx->ctx_doi = XFRM_SC_DOI_LSM;
265 ctx->ctx_alg = XFRM_SC_ALG_SELINUX;
Venkat Yekkiralac1a856c2006-11-08 17:03:44 -0600266 ctx->ctx_sid = sid;
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700267 ctx->ctx_len = str_len;
268 memcpy(ctx->ctx_str,
269 ctx_str,
270 str_len);
271
272 goto out2;
273
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800274out:
Luiz Capitulinoee2e68412006-01-06 22:59:43 -0800275 *ctxp = NULL;
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800276 kfree(ctx);
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700277out2:
278 kfree(ctx_str);
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800279 return rc;
280}
281
282/*
283 * LSM hook implementation that allocs and transfers uctx spec to
284 * xfrm_policy.
285 */
Paul Moore03e1ad72008-04-12 19:07:52 -0700286int selinux_xfrm_policy_alloc(struct xfrm_sec_ctx **ctxp,
287 struct xfrm_user_sec_ctx *uctx)
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800288{
289 int err;
290
Venkat Yekkiralac1a856c2006-11-08 17:03:44 -0600291 BUG_ON(!uctx);
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800292
Paul Moore03e1ad72008-04-12 19:07:52 -0700293 err = selinux_xfrm_sec_ctx_alloc(ctxp, uctx, 0);
Paul Moored621d352008-01-29 08:43:36 -0500294 if (err == 0)
295 atomic_inc(&selinux_xfrm_refcount);
296
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800297 return err;
298}
299
300
301/*
302 * LSM hook implementation that copies security data structure from old to
303 * new for policy cloning.
304 */
Paul Moore03e1ad72008-04-12 19:07:52 -0700305int selinux_xfrm_policy_clone(struct xfrm_sec_ctx *old_ctx,
306 struct xfrm_sec_ctx **new_ctxp)
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800307{
Paul Moore03e1ad72008-04-12 19:07:52 -0700308 struct xfrm_sec_ctx *new_ctx;
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800309
310 if (old_ctx) {
Paul Moore03e1ad72008-04-12 19:07:52 -0700311 new_ctx = kmalloc(sizeof(*old_ctx) + old_ctx->ctx_len,
312 GFP_KERNEL);
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800313 if (!new_ctx)
314 return -ENOMEM;
315
316 memcpy(new_ctx, old_ctx, sizeof(*new_ctx));
317 memcpy(new_ctx->ctx_str, old_ctx->ctx_str, new_ctx->ctx_len);
Paul Moore03e1ad72008-04-12 19:07:52 -0700318 *new_ctxp = new_ctx;
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800319 }
320 return 0;
321}
322
323/*
Paul Moore03e1ad72008-04-12 19:07:52 -0700324 * LSM hook implementation that frees xfrm_sec_ctx security information.
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800325 */
Paul Moore03e1ad72008-04-12 19:07:52 -0700326void selinux_xfrm_policy_free(struct xfrm_sec_ctx *ctx)
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800327{
Eric Paris3c1c88a2008-04-18 17:38:27 -0400328 kfree(ctx);
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800329}
330
331/*
Catherine Zhangc8c05a82006-06-08 23:39:49 -0700332 * LSM hook implementation that authorizes deletion of labeled policies.
333 */
Paul Moore03e1ad72008-04-12 19:07:52 -0700334int selinux_xfrm_policy_delete(struct xfrm_sec_ctx *ctx)
Catherine Zhangc8c05a82006-06-08 23:39:49 -0700335{
David Howells86a264a2008-11-14 10:39:18 +1100336 const struct task_security_struct *tsec = current_security();
Catherine Zhangc8c05a82006-06-08 23:39:49 -0700337 int rc = 0;
338
Paul Moored621d352008-01-29 08:43:36 -0500339 if (ctx) {
Catherine Zhangc8c05a82006-06-08 23:39:49 -0700340 rc = avc_has_perm(tsec->sid, ctx->ctx_sid,
341 SECCLASS_ASSOCIATION,
342 ASSOCIATION__SETCONTEXT, NULL);
Paul Moored621d352008-01-29 08:43:36 -0500343 if (rc == 0)
344 atomic_dec(&selinux_xfrm_refcount);
345 }
Catherine Zhangc8c05a82006-06-08 23:39:49 -0700346
347 return rc;
348}
349
350/*
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800351 * LSM hook implementation that allocs and transfers sec_ctx spec to
352 * xfrm_state.
353 */
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700354int selinux_xfrm_state_alloc(struct xfrm_state *x, struct xfrm_user_sec_ctx *uctx,
Venkat Yekkiralac1a856c2006-11-08 17:03:44 -0600355 u32 secid)
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800356{
357 int err;
358
359 BUG_ON(!x);
360
Venkat Yekkiralac1a856c2006-11-08 17:03:44 -0600361 err = selinux_xfrm_sec_ctx_alloc(&x->security, uctx, secid);
Paul Moored621d352008-01-29 08:43:36 -0500362 if (err == 0)
363 atomic_inc(&selinux_xfrm_refcount);
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800364 return err;
365}
366
367/*
368 * LSM hook implementation that frees xfrm_state security information.
369 */
370void selinux_xfrm_state_free(struct xfrm_state *x)
371{
372 struct xfrm_sec_ctx *ctx = x->security;
Eric Paris3c1c88a2008-04-18 17:38:27 -0400373 kfree(ctx);
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800374}
375
Catherine Zhangc8c05a82006-06-08 23:39:49 -0700376 /*
377 * LSM hook implementation that authorizes deletion of labeled SAs.
378 */
379int selinux_xfrm_state_delete(struct xfrm_state *x)
380{
David Howells86a264a2008-11-14 10:39:18 +1100381 const struct task_security_struct *tsec = current_security();
Catherine Zhangc8c05a82006-06-08 23:39:49 -0700382 struct xfrm_sec_ctx *ctx = x->security;
383 int rc = 0;
384
Paul Moored621d352008-01-29 08:43:36 -0500385 if (ctx) {
Catherine Zhangc8c05a82006-06-08 23:39:49 -0700386 rc = avc_has_perm(tsec->sid, ctx->ctx_sid,
387 SECCLASS_ASSOCIATION,
388 ASSOCIATION__SETCONTEXT, NULL);
Paul Moored621d352008-01-29 08:43:36 -0500389 if (rc == 0)
390 atomic_dec(&selinux_xfrm_refcount);
391 }
Catherine Zhangc8c05a82006-06-08 23:39:49 -0700392
393 return rc;
394}
395
Catherine Zhang2c7946a2006-03-20 22:41:23 -0800396/*
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800397 * LSM hook that controls access to unlabelled packets. If
398 * a xfrm_state is authorizable (defined by macro) then it was
399 * already authorized by the IPSec process. If not, then
400 * we need to check for unlabelled access since this may not have
401 * gone thru the IPSec process.
402 */
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700403int selinux_xfrm_sock_rcv_skb(u32 isec_sid, struct sk_buff *skb,
404 struct avc_audit_data *ad)
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800405{
406 int i, rc = 0;
407 struct sec_path *sp;
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700408 u32 sel_sid = SECINITSID_UNLABELED;
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800409
410 sp = skb->sp;
411
412 if (sp) {
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800413 for (i = 0; i < sp->len; i++) {
Dave Jones67644722006-04-02 23:34:19 -0700414 struct xfrm_state *x = sp->xvec[i];
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800415
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700416 if (x && selinux_authorizable_xfrm(x)) {
417 struct xfrm_sec_ctx *ctx = x->security;
418 sel_sid = ctx->ctx_sid;
419 break;
420 }
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800421 }
422 }
423
Venkat Yekkirala67f83cb2006-11-08 17:04:26 -0600424 /*
425 * This check even when there's no association involved is
426 * intended, according to Trent Jaeger, to make sure a
427 * process can't engage in non-ipsec communication unless
428 * explicitly allowed by policy.
429 */
430
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700431 rc = avc_has_perm(isec_sid, sel_sid, SECCLASS_ASSOCIATION,
432 ASSOCIATION__RECVFROM, ad);
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800433
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800434 return rc;
435}
436
437/*
438 * POSTROUTE_LAST hook's XFRM processing:
439 * If we have no security association, then we need to determine
440 * whether the socket is allowed to send to an unlabelled destination.
441 * If we do have a authorizable security association, then it has already been
Venkat Yekkirala67f83cb2006-11-08 17:04:26 -0600442 * checked in the selinux_xfrm_state_pol_flow_match hook above.
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800443 */
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700444int selinux_xfrm_postroute_last(u32 isec_sid, struct sk_buff *skb,
Venkat Yekkirala67f83cb2006-11-08 17:04:26 -0600445 struct avc_audit_data *ad, u8 proto)
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800446{
447 struct dst_entry *dst;
448 int rc = 0;
449
Eric Dumazetadf30902009-06-02 05:19:30 +0000450 dst = skb_dst(skb);
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800451
452 if (dst) {
453 struct dst_entry *dst_test;
454
Stephen Hemmingerc80544d2007-10-18 03:07:05 -0700455 for (dst_test = dst; dst_test != NULL;
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800456 dst_test = dst_test->child) {
457 struct xfrm_state *x = dst_test->xfrm;
458
459 if (x && selinux_authorizable_xfrm(x))
James Morris4e5ab4c2006-06-09 00:33:33 -0700460 goto out;
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800461 }
462 }
463
Venkat Yekkirala67f83cb2006-11-08 17:04:26 -0600464 switch (proto) {
465 case IPPROTO_AH:
466 case IPPROTO_ESP:
467 case IPPROTO_COMP:
468 /*
469 * We should have already seen this packet once before
470 * it underwent xfrm(s). No need to subject it to the
471 * unlabeled check.
472 */
473 goto out;
474 default:
475 break;
476 }
477
478 /*
479 * This check even when there's no association involved is
480 * intended, according to Trent Jaeger, to make sure a
481 * process can't engage in non-ipsec communication unless
482 * explicitly allowed by policy.
483 */
484
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800485 rc = avc_has_perm(isec_sid, SECINITSID_UNLABELED, SECCLASS_ASSOCIATION,
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700486 ASSOCIATION__SENDTO, ad);
James Morris4e5ab4c2006-06-09 00:33:33 -0700487out:
488 return rc;
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800489}