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1/*
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 *
9 * Updated: Venkat Yekkirala <vyekkirala@TrustedCS.com>
10 *
11 * Granular IPSec Associations for use in MLS environments.
12 *
13 * Copyright (C) 2005 International Business Machines Corporation
14 * Copyright (C) 2006 Trusted Computer Solutions, Inc.
15 *
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 */
34#include <linux/kernel.h>
35#include <linux/init.h>
36#include <linux/security.h>
37#include <linux/types.h>
38#include <linux/slab.h>
39#include <linux/ip.h>
40#include <linux/tcp.h>
41#include <linux/skbuff.h>
42#include <linux/xfrm.h>
43#include <net/xfrm.h>
44#include <net/checksum.h>
45#include <net/udp.h>
46#include <linux/atomic.h>
47
48#include "avc.h"
49#include "objsec.h"
50#include "xfrm.h"
51
52/* Labeled XFRM instance counter */
53atomic_t selinux_xfrm_refcount = ATOMIC_INIT(0);
54
55/*
56 * Returns true if the context is an LSM/SELinux context.
57 */
58static inline int selinux_authorizable_ctx(struct xfrm_sec_ctx *ctx)
59{
60 return (ctx &&
61 (ctx->ctx_doi == XFRM_SC_DOI_LSM) &&
62 (ctx->ctx_alg == XFRM_SC_ALG_SELINUX));
63}
64
65/*
66 * Returns true if the xfrm contains a security blob for SELinux.
67 */
68static inline int selinux_authorizable_xfrm(struct xfrm_state *x)
69{
70 return selinux_authorizable_ctx(x->security);
71}
72
73/*
74 * Allocates a xfrm_sec_state and populates it using the supplied security
75 * xfrm_user_sec_ctx context.
76 */
77static int selinux_xfrm_alloc_user(struct xfrm_sec_ctx **ctxp,
78 struct xfrm_user_sec_ctx *uctx,
79 gfp_t gfp)
80{
81 int rc;
82 const struct task_security_struct *tsec = current_security();
83 struct xfrm_sec_ctx *ctx = NULL;
84 u32 str_len;
85
86 if (ctxp == NULL || uctx == NULL ||
87 uctx->ctx_doi != XFRM_SC_DOI_LSM ||
88 uctx->ctx_alg != XFRM_SC_ALG_SELINUX)
89 return -EINVAL;
90
91 str_len = uctx->ctx_len;
92 if (str_len >= PAGE_SIZE)
93 return -ENOMEM;
94
95 ctx = kmalloc(sizeof(*ctx) + str_len + 1, gfp);
96 if (!ctx)
97 return -ENOMEM;
98
99 ctx->ctx_doi = XFRM_SC_DOI_LSM;
100 ctx->ctx_alg = XFRM_SC_ALG_SELINUX;
101 ctx->ctx_len = str_len;
102 memcpy(ctx->ctx_str, &uctx[1], str_len);
103 ctx->ctx_str[str_len] = '\0';
104 rc = security_context_to_sid(ctx->ctx_str, str_len, &ctx->ctx_sid, gfp);
105 if (rc)
106 goto err;
107
108 rc = avc_has_perm(tsec->sid, ctx->ctx_sid,
109 SECCLASS_ASSOCIATION, ASSOCIATION__SETCONTEXT, NULL);
110 if (rc)
111 goto err;
112
113 *ctxp = ctx;
114 atomic_inc(&selinux_xfrm_refcount);
115 return 0;
116
117err:
118 kfree(ctx);
119 return rc;
120}
121
122/*
123 * Free the xfrm_sec_ctx structure.
124 */
125static void selinux_xfrm_free(struct xfrm_sec_ctx *ctx)
126{
127 if (!ctx)
128 return;
129
130 atomic_dec(&selinux_xfrm_refcount);
131 kfree(ctx);
132}
133
134/*
135 * Authorize the deletion of a labeled SA or policy rule.
136 */
137static int selinux_xfrm_delete(struct xfrm_sec_ctx *ctx)
138{
139 const struct task_security_struct *tsec = current_security();
140
141 if (!ctx)
142 return 0;
143
144 return avc_has_perm(tsec->sid, ctx->ctx_sid,
145 SECCLASS_ASSOCIATION, ASSOCIATION__SETCONTEXT,
146 NULL);
147}
148
149/*
150 * LSM hook implementation that authorizes that a flow can use a xfrm policy
151 * rule.
152 */
153int selinux_xfrm_policy_lookup(struct xfrm_sec_ctx *ctx, u32 fl_secid, u8 dir)
154{
155 int rc;
156
157 /* All flows should be treated as polmatch'ing an otherwise applicable
158 * "non-labeled" policy. This would prevent inadvertent "leaks". */
159 if (!ctx)
160 return 0;
161
162 /* Context sid is either set to label or ANY_ASSOC */
163 if (!selinux_authorizable_ctx(ctx))
164 return -EINVAL;
165
166 rc = avc_has_perm(fl_secid, ctx->ctx_sid,
167 SECCLASS_ASSOCIATION, ASSOCIATION__POLMATCH, NULL);
168 return (rc == -EACCES ? -ESRCH : rc);
169}
170
171/*
172 * LSM hook implementation that authorizes that a state matches
173 * the given policy, flow combo.
174 */
175int selinux_xfrm_state_pol_flow_match(struct xfrm_state *x,
176 struct xfrm_policy *xp,
177 const struct flowi *fl)
178{
179 u32 state_sid;
180
181 if (!xp->security)
182 if (x->security)
183 /* unlabeled policy and labeled SA can't match */
184 return 0;
185 else
186 /* unlabeled policy and unlabeled SA match all flows */
187 return 1;
188 else
189 if (!x->security)
190 /* unlabeled SA and labeled policy can't match */
191 return 0;
192 else
193 if (!selinux_authorizable_xfrm(x))
194 /* Not a SELinux-labeled SA */
195 return 0;
196
197 state_sid = x->security->ctx_sid;
198
199 if (fl->flowi_secid != state_sid)
200 return 0;
201
202 /* We don't need a separate SA Vs. policy polmatch check since the SA
203 * is now of the same label as the flow and a flow Vs. policy polmatch
204 * check had already happened in selinux_xfrm_policy_lookup() above. */
205 return (avc_has_perm(fl->flowi_secid, state_sid,
206 SECCLASS_ASSOCIATION, ASSOCIATION__SENDTO,
207 NULL) ? 0 : 1);
208}
209
210static u32 selinux_xfrm_skb_sid_egress(struct sk_buff *skb)
211{
212 struct dst_entry *dst = skb_dst(skb);
213 struct xfrm_state *x;
214
215 if (dst == NULL)
216 return SECSID_NULL;
217 x = dst->xfrm;
218 if (x == NULL || !selinux_authorizable_xfrm(x))
219 return SECSID_NULL;
220
221 return x->security->ctx_sid;
222}
223
224static int selinux_xfrm_skb_sid_ingress(struct sk_buff *skb,
225 u32 *sid, int ckall)
226{
227 u32 sid_session = SECSID_NULL;
228 struct sec_path *sp = skb->sp;
229
230 if (sp) {
231 int i;
232
233 for (i = sp->len - 1; i >= 0; i--) {
234 struct xfrm_state *x = sp->xvec[i];
235 if (selinux_authorizable_xfrm(x)) {
236 struct xfrm_sec_ctx *ctx = x->security;
237
238 if (sid_session == SECSID_NULL) {
239 sid_session = ctx->ctx_sid;
240 if (!ckall)
241 goto out;
242 } else if (sid_session != ctx->ctx_sid) {
243 *sid = SECSID_NULL;
244 return -EINVAL;
245 }
246 }
247 }
248 }
249
250out:
251 *sid = sid_session;
252 return 0;
253}
254
255/*
256 * LSM hook implementation that checks and/or returns the xfrm sid for the
257 * incoming packet.
258 */
259int selinux_xfrm_decode_session(struct sk_buff *skb, u32 *sid, int ckall)
260{
261 if (skb == NULL) {
262 *sid = SECSID_NULL;
263 return 0;
264 }
265 return selinux_xfrm_skb_sid_ingress(skb, sid, ckall);
266}
267
268int selinux_xfrm_skb_sid(struct sk_buff *skb, u32 *sid)
269{
270 int rc;
271
272 rc = selinux_xfrm_skb_sid_ingress(skb, sid, 0);
273 if (rc == 0 && *sid == SECSID_NULL)
274 *sid = selinux_xfrm_skb_sid_egress(skb);
275
276 return rc;
277}
278
279/*
280 * LSM hook implementation that allocs and transfers uctx spec to xfrm_policy.
281 */
282int selinux_xfrm_policy_alloc(struct xfrm_sec_ctx **ctxp,
283 struct xfrm_user_sec_ctx *uctx,
284 gfp_t gfp)
285{
286 return selinux_xfrm_alloc_user(ctxp, uctx, gfp);
287}
288
289/*
290 * LSM hook implementation that copies security data structure from old to new
291 * for policy cloning.
292 */
293int selinux_xfrm_policy_clone(struct xfrm_sec_ctx *old_ctx,
294 struct xfrm_sec_ctx **new_ctxp)
295{
296 struct xfrm_sec_ctx *new_ctx;
297
298 if (!old_ctx)
299 return 0;
300
301 new_ctx = kmemdup(old_ctx, sizeof(*old_ctx) + old_ctx->ctx_len,
302 GFP_ATOMIC);
303 if (!new_ctx)
304 return -ENOMEM;
305 atomic_inc(&selinux_xfrm_refcount);
306 *new_ctxp = new_ctx;
307
308 return 0;
309}
310
311/*
312 * LSM hook implementation that frees xfrm_sec_ctx security information.
313 */
314void selinux_xfrm_policy_free(struct xfrm_sec_ctx *ctx)
315{
316 selinux_xfrm_free(ctx);
317}
318
319/*
320 * LSM hook implementation that authorizes deletion of labeled policies.
321 */
322int selinux_xfrm_policy_delete(struct xfrm_sec_ctx *ctx)
323{
324 return selinux_xfrm_delete(ctx);
325}
326
327/*
328 * LSM hook implementation that allocates a xfrm_sec_state, populates it using
329 * the supplied security context, and assigns it to the xfrm_state.
330 */
331int selinux_xfrm_state_alloc(struct xfrm_state *x,
332 struct xfrm_user_sec_ctx *uctx)
333{
334 return selinux_xfrm_alloc_user(&x->security, uctx, GFP_KERNEL);
335}
336
337/*
338 * LSM hook implementation that allocates a xfrm_sec_state and populates based
339 * on a secid.
340 */
341int selinux_xfrm_state_alloc_acquire(struct xfrm_state *x,
342 struct xfrm_sec_ctx *polsec, u32 secid)
343{
344 int rc;
345 struct xfrm_sec_ctx *ctx;
346 char *ctx_str = NULL;
347 int str_len;
348
349 if (!polsec)
350 return 0;
351
352 if (secid == 0)
353 return -EINVAL;
354
355 rc = security_sid_to_context(secid, &ctx_str, &str_len);
356 if (rc)
357 return rc;
358
359 ctx = kmalloc(sizeof(*ctx) + str_len, GFP_ATOMIC);
360 if (!ctx) {
361 rc = -ENOMEM;
362 goto out;
363 }
364
365 ctx->ctx_doi = XFRM_SC_DOI_LSM;
366 ctx->ctx_alg = XFRM_SC_ALG_SELINUX;
367 ctx->ctx_sid = secid;
368 ctx->ctx_len = str_len;
369 memcpy(ctx->ctx_str, ctx_str, str_len);
370
371 x->security = ctx;
372 atomic_inc(&selinux_xfrm_refcount);
373out:
374 kfree(ctx_str);
375 return rc;
376}
377
378/*
379 * LSM hook implementation that frees xfrm_state security information.
380 */
381void selinux_xfrm_state_free(struct xfrm_state *x)
382{
383 selinux_xfrm_free(x->security);
384}
385
386/*
387 * LSM hook implementation that authorizes deletion of labeled SAs.
388 */
389int selinux_xfrm_state_delete(struct xfrm_state *x)
390{
391 return selinux_xfrm_delete(x->security);
392}
393
394/*
395 * LSM hook that controls access to unlabelled packets. If
396 * a xfrm_state is authorizable (defined by macro) then it was
397 * already authorized by the IPSec process. If not, then
398 * we need to check for unlabelled access since this may not have
399 * gone thru the IPSec process.
400 */
401int selinux_xfrm_sock_rcv_skb(u32 sk_sid, struct sk_buff *skb,
402 struct common_audit_data *ad)
403{
404 int i;
405 struct sec_path *sp = skb->sp;
406 u32 peer_sid = SECINITSID_UNLABELED;
407
408 if (sp) {
409 for (i = 0; i < sp->len; i++) {
410 struct xfrm_state *x = sp->xvec[i];
411
412 if (x && selinux_authorizable_xfrm(x)) {
413 struct xfrm_sec_ctx *ctx = x->security;
414 peer_sid = ctx->ctx_sid;
415 break;
416 }
417 }
418 }
419
420 /* This check even when there's no association involved is intended,
421 * according to Trent Jaeger, to make sure a process can't engage in
422 * non-IPsec communication unless explicitly allowed by policy. */
423 return avc_has_perm(sk_sid, peer_sid,
424 SECCLASS_ASSOCIATION, ASSOCIATION__RECVFROM, ad);
425}
426
427/*
428 * POSTROUTE_LAST hook's XFRM processing:
429 * If we have no security association, then we need to determine
430 * whether the socket is allowed to send to an unlabelled destination.
431 * If we do have a authorizable security association, then it has already been
432 * checked in the selinux_xfrm_state_pol_flow_match hook above.
433 */
434int selinux_xfrm_postroute_last(u32 sk_sid, struct sk_buff *skb,
435 struct common_audit_data *ad, u8 proto)
436{
437 struct dst_entry *dst;
438
439 switch (proto) {
440 case IPPROTO_AH:
441 case IPPROTO_ESP:
442 case IPPROTO_COMP:
443 /* We should have already seen this packet once before it
444 * underwent xfrm(s). No need to subject it to the unlabeled
445 * check. */
446 return 0;
447 default:
448 break;
449 }
450
451 dst = skb_dst(skb);
452 if (dst) {
453 struct dst_entry *iter;
454
455 for (iter = dst; iter != NULL; iter = iter->child) {
456 struct xfrm_state *x = iter->xfrm;
457
458 if (x && selinux_authorizable_xfrm(x))
459 return 0;
460 }
461 }
462
463 /* This check even when there's no association involved is intended,
464 * according to Trent Jaeger, to make sure a process can't engage in
465 * non-IPsec communication unless explicitly allowed by policy. */
466 return avc_has_perm(sk_sid, SECINITSID_UNLABELED,
467 SECCLASS_ASSOCIATION, ASSOCIATION__SENDTO, ad);
468}
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Security-Enhanced Linux (SELinux) security module
4 *
5 * This file contains the SELinux XFRM hook function implementations.
6 *
7 * Authors: Serge Hallyn <sergeh@us.ibm.com>
8 * Trent Jaeger <jaegert@us.ibm.com>
9 *
10 * Updated: Venkat Yekkirala <vyekkirala@TrustedCS.com>
11 *
12 * Granular IPSec Associations for use in MLS environments.
13 *
14 * Copyright (C) 2005 International Business Machines Corporation
15 * Copyright (C) 2006 Trusted Computer Solutions, Inc.
16 */
17
18/*
19 * USAGE:
20 * NOTES:
21 * 1. Make sure to enable the following options in your kernel config:
22 * CONFIG_SECURITY=y
23 * CONFIG_SECURITY_NETWORK=y
24 * CONFIG_SECURITY_NETWORK_XFRM=y
25 * CONFIG_SECURITY_SELINUX=m/y
26 * ISSUES:
27 * 1. Caching packets, so they are not dropped during negotiation
28 * 2. Emulating a reasonable SO_PEERSEC across machines
29 * 3. Testing addition of sk_policy's with security context via setsockopt
30 */
31#include <linux/kernel.h>
32#include <linux/init.h>
33#include <linux/security.h>
34#include <linux/types.h>
35#include <linux/slab.h>
36#include <linux/ip.h>
37#include <linux/tcp.h>
38#include <linux/skbuff.h>
39#include <linux/xfrm.h>
40#include <net/xfrm.h>
41#include <net/checksum.h>
42#include <net/udp.h>
43#include <linux/atomic.h>
44
45#include "avc.h"
46#include "objsec.h"
47#include "xfrm.h"
48
49/* Labeled XFRM instance counter */
50atomic_t selinux_xfrm_refcount __read_mostly = ATOMIC_INIT(0);
51
52/*
53 * Returns true if the context is an LSM/SELinux context.
54 */
55static inline int selinux_authorizable_ctx(struct xfrm_sec_ctx *ctx)
56{
57 return (ctx &&
58 (ctx->ctx_doi == XFRM_SC_DOI_LSM) &&
59 (ctx->ctx_alg == XFRM_SC_ALG_SELINUX));
60}
61
62/*
63 * Returns true if the xfrm contains a security blob for SELinux.
64 */
65static inline int selinux_authorizable_xfrm(struct xfrm_state *x)
66{
67 return selinux_authorizable_ctx(x->security);
68}
69
70/*
71 * Allocates a xfrm_sec_state and populates it using the supplied security
72 * xfrm_user_sec_ctx context.
73 */
74static int selinux_xfrm_alloc_user(struct xfrm_sec_ctx **ctxp,
75 struct xfrm_user_sec_ctx *uctx,
76 gfp_t gfp)
77{
78 int rc;
79 struct xfrm_sec_ctx *ctx = NULL;
80 u32 str_len;
81
82 if (ctxp == NULL || uctx == NULL ||
83 uctx->ctx_doi != XFRM_SC_DOI_LSM ||
84 uctx->ctx_alg != XFRM_SC_ALG_SELINUX)
85 return -EINVAL;
86
87 str_len = uctx->ctx_len;
88 if (str_len >= PAGE_SIZE)
89 return -ENOMEM;
90
91 ctx = kmalloc(struct_size(ctx, ctx_str, str_len + 1), gfp);
92 if (!ctx)
93 return -ENOMEM;
94
95 ctx->ctx_doi = XFRM_SC_DOI_LSM;
96 ctx->ctx_alg = XFRM_SC_ALG_SELINUX;
97 ctx->ctx_len = str_len;
98 memcpy(ctx->ctx_str, &uctx[1], str_len);
99 ctx->ctx_str[str_len] = '\0';
100 rc = security_context_to_sid(ctx->ctx_str, str_len,
101 &ctx->ctx_sid, gfp);
102 if (rc)
103 goto err;
104
105 rc = avc_has_perm(current_sid(), ctx->ctx_sid,
106 SECCLASS_ASSOCIATION, ASSOCIATION__SETCONTEXT, NULL);
107 if (rc)
108 goto err;
109
110 *ctxp = ctx;
111 atomic_inc(&selinux_xfrm_refcount);
112 return 0;
113
114err:
115 kfree(ctx);
116 return rc;
117}
118
119/*
120 * Free the xfrm_sec_ctx structure.
121 */
122static void selinux_xfrm_free(struct xfrm_sec_ctx *ctx)
123{
124 if (!ctx)
125 return;
126
127 atomic_dec(&selinux_xfrm_refcount);
128 kfree(ctx);
129}
130
131/*
132 * Authorize the deletion of a labeled SA or policy rule.
133 */
134static int selinux_xfrm_delete(struct xfrm_sec_ctx *ctx)
135{
136 if (!ctx)
137 return 0;
138
139 return avc_has_perm(current_sid(), ctx->ctx_sid,
140 SECCLASS_ASSOCIATION, ASSOCIATION__SETCONTEXT,
141 NULL);
142}
143
144/*
145 * LSM hook implementation that authorizes that a flow can use a xfrm policy
146 * rule.
147 */
148int selinux_xfrm_policy_lookup(struct xfrm_sec_ctx *ctx, u32 fl_secid)
149{
150 int rc;
151
152 /* All flows should be treated as polmatch'ing an otherwise applicable
153 * "non-labeled" policy. This would prevent inadvertent "leaks". */
154 if (!ctx)
155 return 0;
156
157 /* Context sid is either set to label or ANY_ASSOC */
158 if (!selinux_authorizable_ctx(ctx))
159 return -EINVAL;
160
161 rc = avc_has_perm(fl_secid, ctx->ctx_sid,
162 SECCLASS_ASSOCIATION, ASSOCIATION__POLMATCH, NULL);
163 return (rc == -EACCES ? -ESRCH : rc);
164}
165
166/*
167 * LSM hook implementation that authorizes that a state matches
168 * the given policy, flow combo.
169 */
170int selinux_xfrm_state_pol_flow_match(struct xfrm_state *x,
171 struct xfrm_policy *xp,
172 const struct flowi_common *flic)
173{
174 u32 state_sid;
175 u32 flic_sid;
176
177 if (!xp->security)
178 if (x->security)
179 /* unlabeled policy and labeled SA can't match */
180 return 0;
181 else
182 /* unlabeled policy and unlabeled SA match all flows */
183 return 1;
184 else
185 if (!x->security)
186 /* unlabeled SA and labeled policy can't match */
187 return 0;
188 else
189 if (!selinux_authorizable_xfrm(x))
190 /* Not a SELinux-labeled SA */
191 return 0;
192
193 state_sid = x->security->ctx_sid;
194 flic_sid = flic->flowic_secid;
195
196 if (flic_sid != state_sid)
197 return 0;
198
199 /* We don't need a separate SA Vs. policy polmatch check since the SA
200 * is now of the same label as the flow and a flow Vs. policy polmatch
201 * check had already happened in selinux_xfrm_policy_lookup() above. */
202 return (avc_has_perm(flic_sid, state_sid,
203 SECCLASS_ASSOCIATION, ASSOCIATION__SENDTO,
204 NULL) ? 0 : 1);
205}
206
207static u32 selinux_xfrm_skb_sid_egress(struct sk_buff *skb)
208{
209 struct dst_entry *dst = skb_dst(skb);
210 struct xfrm_state *x;
211
212 if (dst == NULL)
213 return SECSID_NULL;
214 x = dst->xfrm;
215 if (x == NULL || !selinux_authorizable_xfrm(x))
216 return SECSID_NULL;
217
218 return x->security->ctx_sid;
219}
220
221static int selinux_xfrm_skb_sid_ingress(struct sk_buff *skb,
222 u32 *sid, int ckall)
223{
224 u32 sid_session = SECSID_NULL;
225 struct sec_path *sp = skb_sec_path(skb);
226
227 if (sp) {
228 int i;
229
230 for (i = sp->len - 1; i >= 0; i--) {
231 struct xfrm_state *x = sp->xvec[i];
232 if (selinux_authorizable_xfrm(x)) {
233 struct xfrm_sec_ctx *ctx = x->security;
234
235 if (sid_session == SECSID_NULL) {
236 sid_session = ctx->ctx_sid;
237 if (!ckall)
238 goto out;
239 } else if (sid_session != ctx->ctx_sid) {
240 *sid = SECSID_NULL;
241 return -EINVAL;
242 }
243 }
244 }
245 }
246
247out:
248 *sid = sid_session;
249 return 0;
250}
251
252/*
253 * LSM hook implementation that checks and/or returns the xfrm sid for the
254 * incoming packet.
255 */
256int selinux_xfrm_decode_session(struct sk_buff *skb, u32 *sid, int ckall)
257{
258 if (skb == NULL) {
259 *sid = SECSID_NULL;
260 return 0;
261 }
262 return selinux_xfrm_skb_sid_ingress(skb, sid, ckall);
263}
264
265int selinux_xfrm_skb_sid(struct sk_buff *skb, u32 *sid)
266{
267 int rc;
268
269 rc = selinux_xfrm_skb_sid_ingress(skb, sid, 0);
270 if (rc == 0 && *sid == SECSID_NULL)
271 *sid = selinux_xfrm_skb_sid_egress(skb);
272
273 return rc;
274}
275
276/*
277 * LSM hook implementation that allocs and transfers uctx spec to xfrm_policy.
278 */
279int selinux_xfrm_policy_alloc(struct xfrm_sec_ctx **ctxp,
280 struct xfrm_user_sec_ctx *uctx,
281 gfp_t gfp)
282{
283 return selinux_xfrm_alloc_user(ctxp, uctx, gfp);
284}
285
286/*
287 * LSM hook implementation that copies security data structure from old to new
288 * for policy cloning.
289 */
290int selinux_xfrm_policy_clone(struct xfrm_sec_ctx *old_ctx,
291 struct xfrm_sec_ctx **new_ctxp)
292{
293 struct xfrm_sec_ctx *new_ctx;
294
295 if (!old_ctx)
296 return 0;
297
298 new_ctx = kmemdup(old_ctx, sizeof(*old_ctx) + old_ctx->ctx_len,
299 GFP_ATOMIC);
300 if (!new_ctx)
301 return -ENOMEM;
302 atomic_inc(&selinux_xfrm_refcount);
303 *new_ctxp = new_ctx;
304
305 return 0;
306}
307
308/*
309 * LSM hook implementation that frees xfrm_sec_ctx security information.
310 */
311void selinux_xfrm_policy_free(struct xfrm_sec_ctx *ctx)
312{
313 selinux_xfrm_free(ctx);
314}
315
316/*
317 * LSM hook implementation that authorizes deletion of labeled policies.
318 */
319int selinux_xfrm_policy_delete(struct xfrm_sec_ctx *ctx)
320{
321 return selinux_xfrm_delete(ctx);
322}
323
324/*
325 * LSM hook implementation that allocates a xfrm_sec_state, populates it using
326 * the supplied security context, and assigns it to the xfrm_state.
327 */
328int selinux_xfrm_state_alloc(struct xfrm_state *x,
329 struct xfrm_user_sec_ctx *uctx)
330{
331 return selinux_xfrm_alloc_user(&x->security, uctx, GFP_KERNEL);
332}
333
334/*
335 * LSM hook implementation that allocates a xfrm_sec_state and populates based
336 * on a secid.
337 */
338int selinux_xfrm_state_alloc_acquire(struct xfrm_state *x,
339 struct xfrm_sec_ctx *polsec, u32 secid)
340{
341 int rc;
342 struct xfrm_sec_ctx *ctx;
343 char *ctx_str = NULL;
344 u32 str_len;
345
346 if (!polsec)
347 return 0;
348
349 if (secid == 0)
350 return -EINVAL;
351
352 rc = security_sid_to_context(secid, &ctx_str,
353 &str_len);
354 if (rc)
355 return rc;
356
357 ctx = kmalloc(struct_size(ctx, ctx_str, str_len), GFP_ATOMIC);
358 if (!ctx) {
359 rc = -ENOMEM;
360 goto out;
361 }
362
363 ctx->ctx_doi = XFRM_SC_DOI_LSM;
364 ctx->ctx_alg = XFRM_SC_ALG_SELINUX;
365 ctx->ctx_sid = secid;
366 ctx->ctx_len = str_len;
367 memcpy(ctx->ctx_str, ctx_str, str_len);
368
369 x->security = ctx;
370 atomic_inc(&selinux_xfrm_refcount);
371out:
372 kfree(ctx_str);
373 return rc;
374}
375
376/*
377 * LSM hook implementation that frees xfrm_state security information.
378 */
379void selinux_xfrm_state_free(struct xfrm_state *x)
380{
381 selinux_xfrm_free(x->security);
382}
383
384/*
385 * LSM hook implementation that authorizes deletion of labeled SAs.
386 */
387int selinux_xfrm_state_delete(struct xfrm_state *x)
388{
389 return selinux_xfrm_delete(x->security);
390}
391
392/*
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.
398 */
399int selinux_xfrm_sock_rcv_skb(u32 sk_sid, struct sk_buff *skb,
400 struct common_audit_data *ad)
401{
402 int i;
403 struct sec_path *sp = skb_sec_path(skb);
404 u32 peer_sid = SECINITSID_UNLABELED;
405
406 if (sp) {
407 for (i = 0; i < sp->len; i++) {
408 struct xfrm_state *x = sp->xvec[i];
409
410 if (x && selinux_authorizable_xfrm(x)) {
411 struct xfrm_sec_ctx *ctx = x->security;
412 peer_sid = ctx->ctx_sid;
413 break;
414 }
415 }
416 }
417
418 /* This check even when there's no association involved is intended,
419 * according to Trent Jaeger, to make sure a process can't engage in
420 * non-IPsec communication unless explicitly allowed by policy. */
421 return avc_has_perm(sk_sid, peer_sid,
422 SECCLASS_ASSOCIATION, ASSOCIATION__RECVFROM, ad);
423}
424
425/*
426 * POSTROUTE_LAST hook's XFRM processing:
427 * If we have no security association, then we need to determine
428 * whether the socket is allowed to send to an unlabelled destination.
429 * If we do have a authorizable security association, then it has already been
430 * checked in the selinux_xfrm_state_pol_flow_match hook above.
431 */
432int selinux_xfrm_postroute_last(u32 sk_sid, struct sk_buff *skb,
433 struct common_audit_data *ad, u8 proto)
434{
435 struct dst_entry *dst;
436
437 switch (proto) {
438 case IPPROTO_AH:
439 case IPPROTO_ESP:
440 case IPPROTO_COMP:
441 /* We should have already seen this packet once before it
442 * underwent xfrm(s). No need to subject it to the unlabeled
443 * check. */
444 return 0;
445 default:
446 break;
447 }
448
449 dst = skb_dst(skb);
450 if (dst) {
451 struct dst_entry *iter;
452
453 for (iter = dst; iter != NULL; iter = xfrm_dst_child(iter)) {
454 struct xfrm_state *x = iter->xfrm;
455
456 if (x && selinux_authorizable_xfrm(x))
457 return 0;
458 }
459 }
460
461 /* This check even when there's no association involved is intended,
462 * according to Trent Jaeger, to make sure a process can't engage in
463 * non-IPsec communication unless explicitly allowed by policy. */
464 return avc_has_perm(sk_sid, SECINITSID_UNLABELED,
465 SECCLASS_ASSOCIATION, ASSOCIATION__SENDTO, ad);
466}