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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
50atomic_t selinux_xfrm_refcount __read_mostly = ATOMIC_INIT(0);
51
52
53
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
64
65static inline int selinux_authorizable_xfrm(struct xfrm_state *x)
66{
67 return selinux_authorizable_ctx(x->security);
68}
69
70
71
72
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 const struct task_security_struct *tsec = selinux_cred(current_cred());
80 struct xfrm_sec_ctx *ctx = NULL;
81 u32 str_len;
82
83 if (ctxp == NULL || uctx == NULL ||
84 uctx->ctx_doi != XFRM_SC_DOI_LSM ||
85 uctx->ctx_alg != XFRM_SC_ALG_SELINUX)
86 return -EINVAL;
87
88 str_len = uctx->ctx_len;
89 if (str_len >= PAGE_SIZE)
90 return -ENOMEM;
91
92 ctx = kmalloc(sizeof(*ctx) + str_len + 1, gfp);
93 if (!ctx)
94 return -ENOMEM;
95
96 ctx->ctx_doi = XFRM_SC_DOI_LSM;
97 ctx->ctx_alg = XFRM_SC_ALG_SELINUX;
98 ctx->ctx_len = str_len;
99 memcpy(ctx->ctx_str, &uctx[1], str_len);
100 ctx->ctx_str[str_len] = '\0';
101 rc = security_context_to_sid(&selinux_state, ctx->ctx_str, str_len,
102 &ctx->ctx_sid, gfp);
103 if (rc)
104 goto err;
105
106 rc = avc_has_perm(&selinux_state,
107 tsec->sid, ctx->ctx_sid,
108 SECCLASS_ASSOCIATION, ASSOCIATION__SETCONTEXT, NULL);
109 if (rc)
110 goto err;
111
112 *ctxp = ctx;
113 atomic_inc(&selinux_xfrm_refcount);
114 return 0;
115
116err:
117 kfree(ctx);
118 return rc;
119}
120
121
122
123
124static void selinux_xfrm_free(struct xfrm_sec_ctx *ctx)
125{
126 if (!ctx)
127 return;
128
129 atomic_dec(&selinux_xfrm_refcount);
130 kfree(ctx);
131}
132
133
134
135
136static int selinux_xfrm_delete(struct xfrm_sec_ctx *ctx)
137{
138 const struct task_security_struct *tsec = selinux_cred(current_cred());
139
140 if (!ctx)
141 return 0;
142
143 return avc_has_perm(&selinux_state,
144 tsec->sid, ctx->ctx_sid,
145 SECCLASS_ASSOCIATION, ASSOCIATION__SETCONTEXT,
146 NULL);
147}
148
149
150
151
152
153int selinux_xfrm_policy_lookup(struct xfrm_sec_ctx *ctx, u32 fl_secid)
154{
155 int rc;
156
157
158
159 if (!ctx)
160 return 0;
161
162
163 if (!selinux_authorizable_ctx(ctx))
164 return -EINVAL;
165
166 rc = avc_has_perm(&selinux_state,
167 fl_secid, ctx->ctx_sid,
168 SECCLASS_ASSOCIATION, ASSOCIATION__POLMATCH, NULL);
169 return (rc == -EACCES ? -ESRCH : rc);
170}
171
172
173
174
175
176int selinux_xfrm_state_pol_flow_match(struct xfrm_state *x,
177 struct xfrm_policy *xp,
178 const struct flowi_common *flic)
179{
180 u32 state_sid;
181 u32 flic_sid;
182
183 if (!xp->security)
184 if (x->security)
185
186 return 0;
187 else
188
189 return 1;
190 else
191 if (!x->security)
192
193 return 0;
194 else
195 if (!selinux_authorizable_xfrm(x))
196
197 return 0;
198
199 state_sid = x->security->ctx_sid;
200 flic_sid = flic->flowic_secid;
201
202 if (flic_sid != state_sid)
203 return 0;
204
205
206
207
208 return (avc_has_perm(&selinux_state, flic_sid, state_sid,
209 SECCLASS_ASSOCIATION, ASSOCIATION__SENDTO,
210 NULL) ? 0 : 1);
211}
212
213static u32 selinux_xfrm_skb_sid_egress(struct sk_buff *skb)
214{
215 struct dst_entry *dst = skb_dst(skb);
216 struct xfrm_state *x;
217
218 if (dst == NULL)
219 return SECSID_NULL;
220 x = dst->xfrm;
221 if (x == NULL || !selinux_authorizable_xfrm(x))
222 return SECSID_NULL;
223
224 return x->security->ctx_sid;
225}
226
227static int selinux_xfrm_skb_sid_ingress(struct sk_buff *skb,
228 u32 *sid, int ckall)
229{
230 u32 sid_session = SECSID_NULL;
231 struct sec_path *sp = skb_sec_path(skb);
232
233 if (sp) {
234 int i;
235
236 for (i = sp->len - 1; i >= 0; i--) {
237 struct xfrm_state *x = sp->xvec[i];
238 if (selinux_authorizable_xfrm(x)) {
239 struct xfrm_sec_ctx *ctx = x->security;
240
241 if (sid_session == SECSID_NULL) {
242 sid_session = ctx->ctx_sid;
243 if (!ckall)
244 goto out;
245 } else if (sid_session != ctx->ctx_sid) {
246 *sid = SECSID_NULL;
247 return -EINVAL;
248 }
249 }
250 }
251 }
252
253out:
254 *sid = sid_session;
255 return 0;
256}
257
258
259
260
261
262int selinux_xfrm_decode_session(struct sk_buff *skb, u32 *sid, int ckall)
263{
264 if (skb == NULL) {
265 *sid = SECSID_NULL;
266 return 0;
267 }
268 return selinux_xfrm_skb_sid_ingress(skb, sid, ckall);
269}
270
271int selinux_xfrm_skb_sid(struct sk_buff *skb, u32 *sid)
272{
273 int rc;
274
275 rc = selinux_xfrm_skb_sid_ingress(skb, sid, 0);
276 if (rc == 0 && *sid == SECSID_NULL)
277 *sid = selinux_xfrm_skb_sid_egress(skb);
278
279 return rc;
280}
281
282
283
284
285int selinux_xfrm_policy_alloc(struct xfrm_sec_ctx **ctxp,
286 struct xfrm_user_sec_ctx *uctx,
287 gfp_t gfp)
288{
289 return selinux_xfrm_alloc_user(ctxp, uctx, gfp);
290}
291
292
293
294
295
296int selinux_xfrm_policy_clone(struct xfrm_sec_ctx *old_ctx,
297 struct xfrm_sec_ctx **new_ctxp)
298{
299 struct xfrm_sec_ctx *new_ctx;
300
301 if (!old_ctx)
302 return 0;
303
304 new_ctx = kmemdup(old_ctx, sizeof(*old_ctx) + old_ctx->ctx_len,
305 GFP_ATOMIC);
306 if (!new_ctx)
307 return -ENOMEM;
308 atomic_inc(&selinux_xfrm_refcount);
309 *new_ctxp = new_ctx;
310
311 return 0;
312}
313
314
315
316
317void selinux_xfrm_policy_free(struct xfrm_sec_ctx *ctx)
318{
319 selinux_xfrm_free(ctx);
320}
321
322
323
324
325int selinux_xfrm_policy_delete(struct xfrm_sec_ctx *ctx)
326{
327 return selinux_xfrm_delete(ctx);
328}
329
330
331
332
333
334int selinux_xfrm_state_alloc(struct xfrm_state *x,
335 struct xfrm_user_sec_ctx *uctx)
336{
337 return selinux_xfrm_alloc_user(&x->security, uctx, GFP_KERNEL);
338}
339
340
341
342
343
344int selinux_xfrm_state_alloc_acquire(struct xfrm_state *x,
345 struct xfrm_sec_ctx *polsec, u32 secid)
346{
347 int rc;
348 struct xfrm_sec_ctx *ctx;
349 char *ctx_str = NULL;
350 int str_len;
351
352 if (!polsec)
353 return 0;
354
355 if (secid == 0)
356 return -EINVAL;
357
358 rc = security_sid_to_context(&selinux_state, secid, &ctx_str,
359 &str_len);
360 if (rc)
361 return rc;
362
363 ctx = kmalloc(sizeof(*ctx) + str_len, GFP_ATOMIC);
364 if (!ctx) {
365 rc = -ENOMEM;
366 goto out;
367 }
368
369 ctx->ctx_doi = XFRM_SC_DOI_LSM;
370 ctx->ctx_alg = XFRM_SC_ALG_SELINUX;
371 ctx->ctx_sid = secid;
372 ctx->ctx_len = str_len;
373 memcpy(ctx->ctx_str, ctx_str, str_len);
374
375 x->security = ctx;
376 atomic_inc(&selinux_xfrm_refcount);
377out:
378 kfree(ctx_str);
379 return rc;
380}
381
382
383
384
385void selinux_xfrm_state_free(struct xfrm_state *x)
386{
387 selinux_xfrm_free(x->security);
388}
389
390
391
392
393int selinux_xfrm_state_delete(struct xfrm_state *x)
394{
395 return selinux_xfrm_delete(x->security);
396}
397
398
399
400
401
402
403
404
405int selinux_xfrm_sock_rcv_skb(u32 sk_sid, struct sk_buff *skb,
406 struct common_audit_data *ad)
407{
408 int i;
409 struct sec_path *sp = skb_sec_path(skb);
410 u32 peer_sid = SECINITSID_UNLABELED;
411
412 if (sp) {
413 for (i = 0; i < sp->len; i++) {
414 struct xfrm_state *x = sp->xvec[i];
415
416 if (x && selinux_authorizable_xfrm(x)) {
417 struct xfrm_sec_ctx *ctx = x->security;
418 peer_sid = ctx->ctx_sid;
419 break;
420 }
421 }
422 }
423
424
425
426
427 return avc_has_perm(&selinux_state,
428 sk_sid, peer_sid,
429 SECCLASS_ASSOCIATION, ASSOCIATION__RECVFROM, ad);
430}
431
432
433
434
435
436
437
438
439int selinux_xfrm_postroute_last(u32 sk_sid, struct sk_buff *skb,
440 struct common_audit_data *ad, u8 proto)
441{
442 struct dst_entry *dst;
443
444 switch (proto) {
445 case IPPROTO_AH:
446 case IPPROTO_ESP:
447 case IPPROTO_COMP:
448
449
450
451 return 0;
452 default:
453 break;
454 }
455
456 dst = skb_dst(skb);
457 if (dst) {
458 struct dst_entry *iter;
459
460 for (iter = dst; iter != NULL; iter = xfrm_dst_child(iter)) {
461 struct xfrm_state *x = iter->xfrm;
462
463 if (x && selinux_authorizable_xfrm(x))
464 return 0;
465 }
466 }
467
468
469
470
471 return avc_has_perm(&selinux_state, sk_sid, SECINITSID_UNLABELED,
472 SECCLASS_ASSOCIATION, ASSOCIATION__SENDTO, ad);
473}
474