blob: 68178b76a2b3cf25c02ccb1badda3e0e969f29ab [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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090041#include <linux/slab.h>
Trent Jaegerd28d1e02005-12-13 23:12:40 -080042#include <linux/ip.h>
43#include <linux/tcp.h>
44#include <linux/skbuff.h>
45#include <linux/xfrm.h>
46#include <net/xfrm.h>
47#include <net/checksum.h>
48#include <net/udp.h>
Paul Moored621d352008-01-29 08:43:36 -050049#include <asm/atomic.h>
Trent Jaegerd28d1e02005-12-13 23:12:40 -080050
51#include "avc.h"
52#include "objsec.h"
53#include "xfrm.h"
54
Paul Moored621d352008-01-29 08:43:36 -050055/* Labeled XFRM instance counter */
56atomic_t selinux_xfrm_refcount = ATOMIC_INIT(0);
Trent Jaegerd28d1e02005-12-13 23:12:40 -080057
58/*
59 * Returns true if an LSM/SELinux context
60 */
61static inline int selinux_authorizable_ctx(struct xfrm_sec_ctx *ctx)
62{
63 return (ctx &&
64 (ctx->ctx_doi == XFRM_SC_DOI_LSM) &&
65 (ctx->ctx_alg == XFRM_SC_ALG_SELINUX));
66}
67
68/*
69 * Returns true if the xfrm contains a security blob for SELinux
70 */
71static inline int selinux_authorizable_xfrm(struct xfrm_state *x)
72{
73 return selinux_authorizable_ctx(x->security);
74}
75
76/*
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -070077 * LSM hook implementation that authorizes that a flow can use
78 * a xfrm policy rule.
Trent Jaegerd28d1e02005-12-13 23:12:40 -080079 */
Paul Moore03e1ad72008-04-12 19:07:52 -070080int selinux_xfrm_policy_lookup(struct xfrm_sec_ctx *ctx, u32 fl_secid, u8 dir)
Trent Jaegerd28d1e02005-12-13 23:12:40 -080081{
Venkat Yekkirala5b368e62006-10-05 15:42:18 -050082 int rc;
83 u32 sel_sid;
Trent Jaegerd28d1e02005-12-13 23:12:40 -080084
85 /* Context sid is either set to label or ANY_ASSOC */
Paul Moore03e1ad72008-04-12 19:07:52 -070086 if (ctx) {
Trent Jaegerd28d1e02005-12-13 23:12:40 -080087 if (!selinux_authorizable_ctx(ctx))
88 return -EINVAL;
89
90 sel_sid = ctx->ctx_sid;
Paul Moore03e1ad72008-04-12 19:07:52 -070091 } else
Venkat Yekkirala5b368e62006-10-05 15:42:18 -050092 /*
93 * All flows should be treated as polmatch'ing an
94 * otherwise applicable "non-labeled" policy. This
95 * would prevent inadvertent "leaks".
96 */
97 return 0;
Trent Jaegerd28d1e02005-12-13 23:12:40 -080098
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -070099 rc = avc_has_perm(fl_secid, sel_sid, SECCLASS_ASSOCIATION,
100 ASSOCIATION__POLMATCH,
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800101 NULL);
102
Venkat Yekkirala5b368e62006-10-05 15:42:18 -0500103 if (rc == -EACCES)
Paul Moore03e1ad72008-04-12 19:07:52 -0700104 return -ESRCH;
Venkat Yekkirala5b368e62006-10-05 15:42:18 -0500105
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800106 return rc;
107}
108
109/*
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700110 * LSM hook implementation that authorizes that a state matches
111 * the given policy, flow combo.
112 */
113
114int selinux_xfrm_state_pol_flow_match(struct xfrm_state *x, struct xfrm_policy *xp,
David S. Millere33f7702011-02-22 18:13:15 -0800115 const struct flowi *fl)
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700116{
117 u32 state_sid;
Venkat Yekkirala67f83cb2006-11-08 17:04:26 -0600118 int rc;
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700119
Venkat Yekkirala67f83cb2006-11-08 17:04:26 -0600120 if (!xp->security)
Venkat Yekkirala5b368e62006-10-05 15:42:18 -0500121 if (x->security)
122 /* unlabeled policy and labeled SA can't match */
123 return 0;
124 else
125 /* unlabeled policy and unlabeled SA match all flows */
126 return 1;
Venkat Yekkirala67f83cb2006-11-08 17:04:26 -0600127 else
128 if (!x->security)
129 /* unlabeled SA and labeled policy can't match */
130 return 0;
131 else
132 if (!selinux_authorizable_xfrm(x))
133 /* Not a SELinux-labeled SA */
134 return 0;
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700135
Venkat Yekkirala67f83cb2006-11-08 17:04:26 -0600136 state_sid = x->security->ctx_sid;
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700137
David S. Miller1d28f422011-03-12 00:29:39 -0500138 if (fl->flowi_secid != state_sid)
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700139 return 0;
140
David S. Miller1d28f422011-03-12 00:29:39 -0500141 rc = avc_has_perm(fl->flowi_secid, state_sid, SECCLASS_ASSOCIATION,
Venkat Yekkirala5b368e62006-10-05 15:42:18 -0500142 ASSOCIATION__SENDTO,
143 NULL)? 0:1;
144
Venkat Yekkirala67f83cb2006-11-08 17:04:26 -0600145 /*
146 * We don't need a separate SA Vs. policy polmatch check
147 * since the SA is now of the same label as the flow and
148 * a flow Vs. policy polmatch check had already happened
149 * in selinux_xfrm_policy_lookup() above.
150 */
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700151
152 return rc;
153}
154
155/*
Venkat Yekkirala6b877692006-11-08 17:04:09 -0600156 * LSM hook implementation that checks and/or returns the xfrm sid for the
157 * incoming packet.
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700158 */
159
Venkat Yekkiralabeb8d132006-08-04 23:12:42 -0700160int selinux_xfrm_decode_session(struct sk_buff *skb, u32 *sid, int ckall)
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700161{
162 struct sec_path *sp;
163
Venkat Yekkiralabeb8d132006-08-04 23:12:42 -0700164 *sid = SECSID_NULL;
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700165
166 if (skb == NULL)
167 return 0;
168
169 sp = skb->sp;
170 if (sp) {
171 int i, sid_set = 0;
172
173 for (i = sp->len-1; i >= 0; i--) {
174 struct xfrm_state *x = sp->xvec[i];
175 if (selinux_authorizable_xfrm(x)) {
176 struct xfrm_sec_ctx *ctx = x->security;
177
178 if (!sid_set) {
Venkat Yekkiralabeb8d132006-08-04 23:12:42 -0700179 *sid = ctx->ctx_sid;
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700180 sid_set = 1;
Venkat Yekkiralabeb8d132006-08-04 23:12:42 -0700181
182 if (!ckall)
183 break;
Eric Paris3c1c88a2008-04-18 17:38:27 -0400184 } else if (*sid != ctx->ctx_sid)
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700185 return -EINVAL;
186 }
187 }
188 }
189
190 return 0;
191}
192
193/*
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800194 * Security blob allocation for xfrm_policy and xfrm_state
195 * CTX does not have a meaningful value on input
196 */
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700197static int selinux_xfrm_sec_ctx_alloc(struct xfrm_sec_ctx **ctxp,
Venkat Yekkiralac1a856c2006-11-08 17:03:44 -0600198 struct xfrm_user_sec_ctx *uctx, u32 sid)
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800199{
200 int rc = 0;
David Howells86a264a2008-11-14 10:39:18 +1100201 const struct task_security_struct *tsec = current_security();
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700202 struct xfrm_sec_ctx *ctx = NULL;
203 char *ctx_str = NULL;
204 u32 str_len;
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700205
Venkat Yekkiralac1a856c2006-11-08 17:03:44 -0600206 BUG_ON(uctx && sid);
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700207
Venkat Yekkiralacb969f02006-07-24 23:32:20 -0700208 if (!uctx)
209 goto not_from_user;
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700210
Steffen Klassert8f82a682011-02-23 12:54:33 +0100211 if (uctx->ctx_alg != XFRM_SC_ALG_SELINUX)
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700212 return -EINVAL;
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800213
Stephen Rothwell57002bf2007-10-31 16:47:19 +1100214 str_len = uctx->ctx_len;
215 if (str_len >= PAGE_SIZE)
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800216 return -ENOMEM;
217
218 *ctxp = ctx = kmalloc(sizeof(*ctx) +
Stephen Rothwell57002bf2007-10-31 16:47:19 +1100219 str_len + 1,
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800220 GFP_KERNEL);
221
222 if (!ctx)
223 return -ENOMEM;
224
225 ctx->ctx_doi = uctx->ctx_doi;
Stephen Rothwell57002bf2007-10-31 16:47:19 +1100226 ctx->ctx_len = str_len;
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800227 ctx->ctx_alg = uctx->ctx_alg;
228
229 memcpy(ctx->ctx_str,
230 uctx+1,
Stephen Rothwell57002bf2007-10-31 16:47:19 +1100231 str_len);
232 ctx->ctx_str[str_len] = 0;
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800233 rc = security_context_to_sid(ctx->ctx_str,
Stephen Rothwell57002bf2007-10-31 16:47:19 +1100234 str_len,
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800235 &ctx->ctx_sid);
236
237 if (rc)
238 goto out;
239
240 /*
Catherine Zhangc8c05a82006-06-08 23:39:49 -0700241 * Does the subject have permission to set security context?
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800242 */
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800243 rc = avc_has_perm(tsec->sid, ctx->ctx_sid,
244 SECCLASS_ASSOCIATION,
Trent Jaeger5f8ac642006-01-06 13:22:39 -0800245 ASSOCIATION__SETCONTEXT, NULL);
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800246 if (rc)
247 goto out;
248
249 return rc;
250
Venkat Yekkiralacb969f02006-07-24 23:32:20 -0700251not_from_user:
Venkat Yekkiralac1a856c2006-11-08 17:03:44 -0600252 rc = security_sid_to_context(sid, &ctx_str, &str_len);
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700253 if (rc)
254 goto out;
255
256 *ctxp = ctx = kmalloc(sizeof(*ctx) +
257 str_len,
258 GFP_ATOMIC);
259
260 if (!ctx) {
261 rc = -ENOMEM;
262 goto out;
263 }
264
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700265 ctx->ctx_doi = XFRM_SC_DOI_LSM;
266 ctx->ctx_alg = XFRM_SC_ALG_SELINUX;
Venkat Yekkiralac1a856c2006-11-08 17:03:44 -0600267 ctx->ctx_sid = sid;
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700268 ctx->ctx_len = str_len;
269 memcpy(ctx->ctx_str,
270 ctx_str,
271 str_len);
272
273 goto out2;
274
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800275out:
Luiz Capitulinoee2e68412006-01-06 22:59:43 -0800276 *ctxp = NULL;
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800277 kfree(ctx);
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700278out2:
279 kfree(ctx_str);
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800280 return rc;
281}
282
283/*
284 * LSM hook implementation that allocs and transfers uctx spec to
285 * xfrm_policy.
286 */
Paul Moore03e1ad72008-04-12 19:07:52 -0700287int selinux_xfrm_policy_alloc(struct xfrm_sec_ctx **ctxp,
288 struct xfrm_user_sec_ctx *uctx)
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800289{
290 int err;
291
Venkat Yekkiralac1a856c2006-11-08 17:03:44 -0600292 BUG_ON(!uctx);
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800293
Paul Moore03e1ad72008-04-12 19:07:52 -0700294 err = selinux_xfrm_sec_ctx_alloc(ctxp, uctx, 0);
Paul Moored621d352008-01-29 08:43:36 -0500295 if (err == 0)
296 atomic_inc(&selinux_xfrm_refcount);
297
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800298 return err;
299}
300
301
302/*
303 * LSM hook implementation that copies security data structure from old to
304 * new for policy cloning.
305 */
Paul Moore03e1ad72008-04-12 19:07:52 -0700306int selinux_xfrm_policy_clone(struct xfrm_sec_ctx *old_ctx,
307 struct xfrm_sec_ctx **new_ctxp)
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800308{
Paul Moore03e1ad72008-04-12 19:07:52 -0700309 struct xfrm_sec_ctx *new_ctx;
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800310
311 if (old_ctx) {
Paul Moore03e1ad72008-04-12 19:07:52 -0700312 new_ctx = kmalloc(sizeof(*old_ctx) + old_ctx->ctx_len,
313 GFP_KERNEL);
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800314 if (!new_ctx)
315 return -ENOMEM;
316
317 memcpy(new_ctx, old_ctx, sizeof(*new_ctx));
318 memcpy(new_ctx->ctx_str, old_ctx->ctx_str, new_ctx->ctx_len);
Paul Moore03e1ad72008-04-12 19:07:52 -0700319 *new_ctxp = new_ctx;
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800320 }
321 return 0;
322}
323
324/*
Paul Moore03e1ad72008-04-12 19:07:52 -0700325 * LSM hook implementation that frees xfrm_sec_ctx security information.
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800326 */
Paul Moore03e1ad72008-04-12 19:07:52 -0700327void selinux_xfrm_policy_free(struct xfrm_sec_ctx *ctx)
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800328{
Eric Paris3c1c88a2008-04-18 17:38:27 -0400329 kfree(ctx);
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800330}
331
332/*
Catherine Zhangc8c05a82006-06-08 23:39:49 -0700333 * LSM hook implementation that authorizes deletion of labeled policies.
334 */
Paul Moore03e1ad72008-04-12 19:07:52 -0700335int selinux_xfrm_policy_delete(struct xfrm_sec_ctx *ctx)
Catherine Zhangc8c05a82006-06-08 23:39:49 -0700336{
David Howells86a264a2008-11-14 10:39:18 +1100337 const struct task_security_struct *tsec = current_security();
Catherine Zhangc8c05a82006-06-08 23:39:49 -0700338 int rc = 0;
339
Paul Moored621d352008-01-29 08:43:36 -0500340 if (ctx) {
Catherine Zhangc8c05a82006-06-08 23:39:49 -0700341 rc = avc_has_perm(tsec->sid, ctx->ctx_sid,
342 SECCLASS_ASSOCIATION,
343 ASSOCIATION__SETCONTEXT, NULL);
Paul Moored621d352008-01-29 08:43:36 -0500344 if (rc == 0)
345 atomic_dec(&selinux_xfrm_refcount);
346 }
Catherine Zhangc8c05a82006-06-08 23:39:49 -0700347
348 return rc;
349}
350
351/*
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800352 * LSM hook implementation that allocs and transfers sec_ctx spec to
353 * xfrm_state.
354 */
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700355int selinux_xfrm_state_alloc(struct xfrm_state *x, struct xfrm_user_sec_ctx *uctx,
Venkat Yekkiralac1a856c2006-11-08 17:03:44 -0600356 u32 secid)
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800357{
358 int err;
359
360 BUG_ON(!x);
361
Venkat Yekkiralac1a856c2006-11-08 17:03:44 -0600362 err = selinux_xfrm_sec_ctx_alloc(&x->security, uctx, secid);
Paul Moored621d352008-01-29 08:43:36 -0500363 if (err == 0)
364 atomic_inc(&selinux_xfrm_refcount);
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800365 return err;
366}
367
368/*
369 * LSM hook implementation that frees xfrm_state security information.
370 */
371void selinux_xfrm_state_free(struct xfrm_state *x)
372{
373 struct xfrm_sec_ctx *ctx = x->security;
Eric Paris3c1c88a2008-04-18 17:38:27 -0400374 kfree(ctx);
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800375}
376
Catherine Zhangc8c05a82006-06-08 23:39:49 -0700377 /*
378 * LSM hook implementation that authorizes deletion of labeled SAs.
379 */
380int selinux_xfrm_state_delete(struct xfrm_state *x)
381{
David Howells86a264a2008-11-14 10:39:18 +1100382 const struct task_security_struct *tsec = current_security();
Catherine Zhangc8c05a82006-06-08 23:39:49 -0700383 struct xfrm_sec_ctx *ctx = x->security;
384 int rc = 0;
385
Paul Moored621d352008-01-29 08:43:36 -0500386 if (ctx) {
Catherine Zhangc8c05a82006-06-08 23:39:49 -0700387 rc = avc_has_perm(tsec->sid, ctx->ctx_sid,
388 SECCLASS_ASSOCIATION,
389 ASSOCIATION__SETCONTEXT, NULL);
Paul Moored621d352008-01-29 08:43:36 -0500390 if (rc == 0)
391 atomic_dec(&selinux_xfrm_refcount);
392 }
Catherine Zhangc8c05a82006-06-08 23:39:49 -0700393
394 return rc;
395}
396
Catherine Zhang2c7946a2006-03-20 22:41:23 -0800397/*
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800398 * LSM hook that controls access to unlabelled packets. If
399 * a xfrm_state is authorizable (defined by macro) then it was
400 * already authorized by the IPSec process. If not, then
401 * we need to check for unlabelled access since this may not have
402 * gone thru the IPSec process.
403 */
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700404int selinux_xfrm_sock_rcv_skb(u32 isec_sid, struct sk_buff *skb,
Thomas Liu2bf49692009-07-14 12:14:09 -0400405 struct common_audit_data *ad)
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800406{
407 int i, rc = 0;
408 struct sec_path *sp;
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700409 u32 sel_sid = SECINITSID_UNLABELED;
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800410
411 sp = skb->sp;
412
413 if (sp) {
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800414 for (i = 0; i < sp->len; i++) {
Dave Jones67644722006-04-02 23:34:19 -0700415 struct xfrm_state *x = sp->xvec[i];
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800416
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700417 if (x && selinux_authorizable_xfrm(x)) {
418 struct xfrm_sec_ctx *ctx = x->security;
419 sel_sid = ctx->ctx_sid;
420 break;
421 }
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800422 }
423 }
424
Venkat Yekkirala67f83cb2006-11-08 17:04:26 -0600425 /*
426 * This check even when there's no association involved is
427 * intended, according to Trent Jaeger, to make sure a
428 * process can't engage in non-ipsec communication unless
429 * explicitly allowed by policy.
430 */
431
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700432 rc = avc_has_perm(isec_sid, sel_sid, SECCLASS_ASSOCIATION,
433 ASSOCIATION__RECVFROM, ad);
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800434
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800435 return rc;
436}
437
438/*
439 * POSTROUTE_LAST hook's XFRM processing:
440 * If we have no security association, then we need to determine
441 * whether the socket is allowed to send to an unlabelled destination.
442 * If we do have a authorizable security association, then it has already been
Venkat Yekkirala67f83cb2006-11-08 17:04:26 -0600443 * checked in the selinux_xfrm_state_pol_flow_match hook above.
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800444 */
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700445int selinux_xfrm_postroute_last(u32 isec_sid, struct sk_buff *skb,
Thomas Liu2bf49692009-07-14 12:14:09 -0400446 struct common_audit_data *ad, u8 proto)
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800447{
448 struct dst_entry *dst;
449 int rc = 0;
450
Eric Dumazetadf30902009-06-02 05:19:30 +0000451 dst = skb_dst(skb);
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800452
453 if (dst) {
454 struct dst_entry *dst_test;
455
Stephen Hemmingerc80544d2007-10-18 03:07:05 -0700456 for (dst_test = dst; dst_test != NULL;
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800457 dst_test = dst_test->child) {
458 struct xfrm_state *x = dst_test->xfrm;
459
460 if (x && selinux_authorizable_xfrm(x))
James Morris4e5ab4c2006-06-09 00:33:33 -0700461 goto out;
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800462 }
463 }
464
Venkat Yekkirala67f83cb2006-11-08 17:04:26 -0600465 switch (proto) {
466 case IPPROTO_AH:
467 case IPPROTO_ESP:
468 case IPPROTO_COMP:
469 /*
470 * We should have already seen this packet once before
471 * it underwent xfrm(s). No need to subject it to the
472 * unlabeled check.
473 */
474 goto out;
475 default:
476 break;
477 }
478
479 /*
480 * This check even when there's no association involved is
481 * intended, according to Trent Jaeger, to make sure a
482 * process can't engage in non-ipsec communication unless
483 * explicitly allowed by policy.
484 */
485
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800486 rc = avc_has_perm(isec_sid, SECINITSID_UNLABELED, SECCLASS_ASSOCIATION,
Venkat Yekkiralae0d1caa2006-07-24 23:29:07 -0700487 ASSOCIATION__SENDTO, ad);
James Morris4e5ab4c2006-06-09 00:33:33 -0700488out:
489 return rc;
Trent Jaegerd28d1e02005-12-13 23:12:40 -0800490}