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Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
[linux-btrfs-devel.git] / net / xfrm / xfrm_replay.c
blob6ca357406ea8ac178458363fd9fc6be3c467c10c
1 /*
2 * xfrm_replay.c - xfrm replay detection, derived from xfrm_state.c.
3 *
4 * Copyright (C) 2010 secunet Security Networks AG
5 * Copyright (C) 2010 Steffen Klassert <steffen.klassert@secunet.com>
6 *
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms and conditions of the GNU General Public License,
9 * version 2, as published by the Free Software Foundation.
10 *
11 * This program is distributed in the hope it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
14 * more details.
15 *
16 * You should have received a copy of the GNU General Public License along with
17 * this program; if not, write to the Free Software Foundation, Inc.,
18 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
19 */
20
21 #include <net/xfrm.h>
22
23 u32 xfrm_replay_seqhi(struct xfrm_state *x, __be32 net_seq)
24 {
25 u32 seq, seq_hi, bottom;
26 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
27
28 if (!(x->props.flags & XFRM_STATE_ESN))
29 return 0;
30
31 seq = ntohl(net_seq);
32 seq_hi = replay_esn->seq_hi;
33 bottom = replay_esn->seq - replay_esn->replay_window + 1;
34
35 if (likely(replay_esn->seq >= replay_esn->replay_window - 1)) {
36 /* A. same subspace */
37 if (unlikely(seq < bottom))
38 seq_hi++;
39 } else {
40 /* B. window spans two subspaces */
41 if (unlikely(seq >= bottom))
42 seq_hi--;
43 }
44
45 return seq_hi;
46 }
47
48 static void xfrm_replay_notify(struct xfrm_state *x, int event)
49 {
50 struct km_event c;
51 /* we send notify messages in case
52 * 1. we updated on of the sequence numbers, and the seqno difference
53 * is at least x->replay_maxdiff, in this case we also update the
54 * timeout of our timer function
55 * 2. if x->replay_maxage has elapsed since last update,
56 * and there were changes
57 *
58 * The state structure must be locked!
59 */
60
61 switch (event) {
62 case XFRM_REPLAY_UPDATE:
63 if (x->replay_maxdiff &&
64 (x->replay.seq - x->preplay.seq < x->replay_maxdiff) &&
65 (x->replay.oseq - x->preplay.oseq < x->replay_maxdiff)) {
66 if (x->xflags & XFRM_TIME_DEFER)
67 event = XFRM_REPLAY_TIMEOUT;
68 else
69 return;
70 }
71
72 break;
73
74 case XFRM_REPLAY_TIMEOUT:
75 if (memcmp(&x->replay, &x->preplay,
76 sizeof(struct xfrm_replay_state)) == 0) {
77 x->xflags |= XFRM_TIME_DEFER;
78 return;
79 }
80
81 break;
82 }
83
84 memcpy(&x->preplay, &x->replay, sizeof(struct xfrm_replay_state));
85 c.event = XFRM_MSG_NEWAE;
86 c.data.aevent = event;
87 km_state_notify(x, &c);
88
89 if (x->replay_maxage &&
90 !mod_timer(&x->rtimer, jiffies + x->replay_maxage))
91 x->xflags &= ~XFRM_TIME_DEFER;
92 }
93
94 static int xfrm_replay_overflow(struct xfrm_state *x, struct sk_buff *skb)
95 {
96 int err = 0;
97 struct net *net = xs_net(x);
98
99 if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
100 XFRM_SKB_CB(skb)->seq.output.low = ++x->replay.oseq;
101 if (unlikely(x->replay.oseq == 0)) {
102 x->replay.oseq--;
103 xfrm_audit_state_replay_overflow(x, skb);
104 err = -EOVERFLOW;
105
106 return err;
107 }
108 if (xfrm_aevent_is_on(net))
109 x->repl->notify(x, XFRM_REPLAY_UPDATE);
110 }
111
112 return err;
113 }
114
115 static int xfrm_replay_check(struct xfrm_state *x,
116 struct sk_buff *skb, __be32 net_seq)
117 {
118 u32 diff;
119 u32 seq = ntohl(net_seq);
120
121 if (!x->props.replay_window)
122 return 0;
123
124 if (unlikely(seq == 0))
125 goto err;
126
127 if (likely(seq > x->replay.seq))
128 return 0;
129
130 diff = x->replay.seq - seq;
131 if (diff >= min_t(unsigned int, x->props.replay_window,
132 sizeof(x->replay.bitmap) * 8)) {
133 x->stats.replay_window++;
134 goto err;
135 }
136
137 if (x->replay.bitmap & (1U << diff)) {
138 x->stats.replay++;
139 goto err;
140 }
141 return 0;
142
143 err:
144 xfrm_audit_state_replay(x, skb, net_seq);
145 return -EINVAL;
146 }
147
148 static void xfrm_replay_advance(struct xfrm_state *x, __be32 net_seq)
149 {
150 u32 diff;
151 u32 seq = ntohl(net_seq);
152
153 if (!x->props.replay_window)
154 return;
155
156 if (seq > x->replay.seq) {
157 diff = seq - x->replay.seq;
158 if (diff < x->props.replay_window)
159 x->replay.bitmap = ((x->replay.bitmap) << diff) | 1;
160 else
161 x->replay.bitmap = 1;
162 x->replay.seq = seq;
163 } else {
164 diff = x->replay.seq - seq;
165 x->replay.bitmap |= (1U << diff);
166 }
167
168 if (xfrm_aevent_is_on(xs_net(x)))
169 xfrm_replay_notify(x, XFRM_REPLAY_UPDATE);
170 }
171
172 static int xfrm_replay_overflow_bmp(struct xfrm_state *x, struct sk_buff *skb)
173 {
174 int err = 0;
175 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
176 struct net *net = xs_net(x);
177
178 if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
179 XFRM_SKB_CB(skb)->seq.output.low = ++replay_esn->oseq;
180 if (unlikely(replay_esn->oseq == 0)) {
181 replay_esn->oseq--;
182 xfrm_audit_state_replay_overflow(x, skb);
183 err = -EOVERFLOW;
184
185 return err;
186 }
187 if (xfrm_aevent_is_on(net))
188 x->repl->notify(x, XFRM_REPLAY_UPDATE);
189 }
190
191 return err;
192 }
193
194 static int xfrm_replay_check_bmp(struct xfrm_state *x,
195 struct sk_buff *skb, __be32 net_seq)
196 {
197 unsigned int bitnr, nr;
198 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
199 u32 pos;
200 u32 seq = ntohl(net_seq);
201 u32 diff = replay_esn->seq - seq;
202
203 if (!replay_esn->replay_window)
204 return 0;
205
206 if (unlikely(seq == 0))
207 goto err;
208
209 if (likely(seq > replay_esn->seq))
210 return 0;
211
212 if (diff >= replay_esn->replay_window) {
213 x->stats.replay_window++;
214 goto err;
215 }
216
217 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
218
219 if (pos >= diff)
220 bitnr = (pos - diff) % replay_esn->replay_window;
221 else
222 bitnr = replay_esn->replay_window - (diff - pos);
223
224 nr = bitnr >> 5;
225 bitnr = bitnr & 0x1F;
226 if (replay_esn->bmp[nr] & (1U << bitnr))
227 goto err_replay;
228
229 return 0;
230
231 err_replay:
232 x->stats.replay++;
233 err:
234 xfrm_audit_state_replay(x, skb, net_seq);
235 return -EINVAL;
236 }
237
238 static void xfrm_replay_advance_bmp(struct xfrm_state *x, __be32 net_seq)
239 {
240 unsigned int bitnr, nr, i;
241 u32 diff;
242 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
243 u32 seq = ntohl(net_seq);
244 u32 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
245
246 if (!replay_esn->replay_window)
247 return;
248
249 if (seq > replay_esn->seq) {
250 diff = seq - replay_esn->seq;
251
252 if (diff < replay_esn->replay_window) {
253 for (i = 1; i < diff; i++) {
254 bitnr = (pos + i) % replay_esn->replay_window;
255 nr = bitnr >> 5;
256 bitnr = bitnr & 0x1F;
257 replay_esn->bmp[nr] &= ~(1U << bitnr);
258 }
259 } else {
260 nr = (replay_esn->replay_window - 1) >> 5;
261 for (i = 0; i <= nr; i++)
262 replay_esn->bmp[i] = 0;
263 }
264
265 bitnr = (pos + diff) % replay_esn->replay_window;
266 replay_esn->seq = seq;
267 } else {
268 diff = replay_esn->seq - seq;
269
270 if (pos >= diff)
271 bitnr = (pos - diff) % replay_esn->replay_window;
272 else
273 bitnr = replay_esn->replay_window - (diff - pos);
274 }
275
276 nr = bitnr >> 5;
277 bitnr = bitnr & 0x1F;
278 replay_esn->bmp[nr] |= (1U << bitnr);
279
280 if (xfrm_aevent_is_on(xs_net(x)))
281 xfrm_replay_notify(x, XFRM_REPLAY_UPDATE);
282 }
283
284 static void xfrm_replay_notify_bmp(struct xfrm_state *x, int event)
285 {
286 struct km_event c;
287 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
288 struct xfrm_replay_state_esn *preplay_esn = x->preplay_esn;
289
290 /* we send notify messages in case
291 * 1. we updated on of the sequence numbers, and the seqno difference
292 * is at least x->replay_maxdiff, in this case we also update the
293 * timeout of our timer function
294 * 2. if x->replay_maxage has elapsed since last update,
295 * and there were changes
296 *
297 * The state structure must be locked!
298 */
299
300 switch (event) {
301 case XFRM_REPLAY_UPDATE:
302 if (x->replay_maxdiff &&
303 (replay_esn->seq - preplay_esn->seq < x->replay_maxdiff) &&
304 (replay_esn->oseq - preplay_esn->oseq < x->replay_maxdiff)) {
305 if (x->xflags & XFRM_TIME_DEFER)
306 event = XFRM_REPLAY_TIMEOUT;
307 else
308 return;
309 }
310
311 break;
312
313 case XFRM_REPLAY_TIMEOUT:
314 if (memcmp(x->replay_esn, x->preplay_esn,
315 xfrm_replay_state_esn_len(replay_esn)) == 0) {
316 x->xflags |= XFRM_TIME_DEFER;
317 return;
318 }
319
320 break;
321 }
322
323 memcpy(x->preplay_esn, x->replay_esn,
324 xfrm_replay_state_esn_len(replay_esn));
325 c.event = XFRM_MSG_NEWAE;
326 c.data.aevent = event;
327 km_state_notify(x, &c);
328
329 if (x->replay_maxage &&
330 !mod_timer(&x->rtimer, jiffies + x->replay_maxage))
331 x->xflags &= ~XFRM_TIME_DEFER;
332 }
333
334 static int xfrm_replay_overflow_esn(struct xfrm_state *x, struct sk_buff *skb)
335 {
336 int err = 0;
337 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
338 struct net *net = xs_net(x);
339
340 if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
341 XFRM_SKB_CB(skb)->seq.output.low = ++replay_esn->oseq;
342 XFRM_SKB_CB(skb)->seq.output.hi = replay_esn->oseq_hi;
343
344 if (unlikely(replay_esn->oseq == 0)) {
345 XFRM_SKB_CB(skb)->seq.output.hi = ++replay_esn->oseq_hi;
346
347 if (replay_esn->oseq_hi == 0) {
348 replay_esn->oseq--;
349 replay_esn->oseq_hi--;
350 xfrm_audit_state_replay_overflow(x, skb);
351 err = -EOVERFLOW;
352
353 return err;
354 }
355 }
356 if (xfrm_aevent_is_on(net))
357 x->repl->notify(x, XFRM_REPLAY_UPDATE);
358 }
359
360 return err;
361 }
362
363 static int xfrm_replay_check_esn(struct xfrm_state *x,
364 struct sk_buff *skb, __be32 net_seq)
365 {
366 unsigned int bitnr, nr;
367 u32 diff;
368 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
369 u32 pos;
370 u32 seq = ntohl(net_seq);
371 u32 wsize = replay_esn->replay_window;
372 u32 top = replay_esn->seq;
373 u32 bottom = top - wsize + 1;
374
375 if (!wsize)
376 return 0;
377
378 if (unlikely(seq == 0 && replay_esn->seq_hi == 0 &&
379 (replay_esn->seq < replay_esn->replay_window - 1)))
380 goto err;
381
382 diff = top - seq;
383
384 if (likely(top >= wsize - 1)) {
385 /* A. same subspace */
386 if (likely(seq > top) || seq < bottom)
387 return 0;
388 } else {
389 /* B. window spans two subspaces */
390 if (likely(seq > top && seq < bottom))
391 return 0;
392 if (seq >= bottom)
393 diff = ~seq + top + 1;
394 }
395
396 if (diff >= replay_esn->replay_window) {
397 x->stats.replay_window++;
398 goto err;
399 }
400
401 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
402
403 if (pos >= diff)
404 bitnr = (pos - diff) % replay_esn->replay_window;
405 else
406 bitnr = replay_esn->replay_window - (diff - pos);
407
408 nr = bitnr >> 5;
409 bitnr = bitnr & 0x1F;
410 if (replay_esn->bmp[nr] & (1U << bitnr))
411 goto err_replay;
412
413 return 0;
414
415 err_replay:
416 x->stats.replay++;
417 err:
418 xfrm_audit_state_replay(x, skb, net_seq);
419 return -EINVAL;
420 }
421
422 static void xfrm_replay_advance_esn(struct xfrm_state *x, __be32 net_seq)
423 {
424 unsigned int bitnr, nr, i;
425 int wrap;
426 u32 diff, pos, seq, seq_hi;
427 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
428
429 if (!replay_esn->replay_window)
430 return;
431
432 seq = ntohl(net_seq);
433 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
434 seq_hi = xfrm_replay_seqhi(x, net_seq);
435 wrap = seq_hi - replay_esn->seq_hi;
436
437 if ((!wrap && seq > replay_esn->seq) || wrap > 0) {
438 if (likely(!wrap))
439 diff = seq - replay_esn->seq;
440 else
441 diff = ~replay_esn->seq + seq + 1;
442
443 if (diff < replay_esn->replay_window) {
444 for (i = 1; i < diff; i++) {
445 bitnr = (pos + i) % replay_esn->replay_window;
446 nr = bitnr >> 5;
447 bitnr = bitnr & 0x1F;
448 replay_esn->bmp[nr] &= ~(1U << bitnr);
449 }
450 } else {
451 nr = (replay_esn->replay_window - 1) >> 5;
452 for (i = 0; i <= nr; i++)
453 replay_esn->bmp[i] = 0;
454 }
455
456 bitnr = (pos + diff) % replay_esn->replay_window;
457 replay_esn->seq = seq;
458
459 if (unlikely(wrap > 0))
460 replay_esn->seq_hi++;
461 } else {
462 diff = replay_esn->seq - seq;
463
464 if (pos >= diff)
465 bitnr = (pos - diff) % replay_esn->replay_window;
466 else
467 bitnr = replay_esn->replay_window - (diff - pos);
468 }
469
470 nr = bitnr >> 5;
471 bitnr = bitnr & 0x1F;
472 replay_esn->bmp[nr] |= (1U << bitnr);
473
474 if (xfrm_aevent_is_on(xs_net(x)))
475 xfrm_replay_notify(x, XFRM_REPLAY_UPDATE);
476 }
477
478 static struct xfrm_replay xfrm_replay_legacy = {
479 .advance = xfrm_replay_advance,
480 .check = xfrm_replay_check,
481 .notify = xfrm_replay_notify,
482 .overflow = xfrm_replay_overflow,
483 };
484
485 static struct xfrm_replay xfrm_replay_bmp = {
486 .advance = xfrm_replay_advance_bmp,
487 .check = xfrm_replay_check_bmp,
488 .notify = xfrm_replay_notify_bmp,
489 .overflow = xfrm_replay_overflow_bmp,
490 };
491
492 static struct xfrm_replay xfrm_replay_esn = {
493 .advance = xfrm_replay_advance_esn,
494 .check = xfrm_replay_check_esn,
495 .notify = xfrm_replay_notify_bmp,
496 .overflow = xfrm_replay_overflow_esn,
497 };
498
499 int xfrm_init_replay(struct xfrm_state *x)
500 {
501 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
502
503 if (replay_esn) {
504 if (replay_esn->replay_window >
505 replay_esn->bmp_len * sizeof(__u32) * 8)
506 return -EINVAL;
507
508 if ((x->props.flags & XFRM_STATE_ESN) && replay_esn->replay_window == 0)
509 return -EINVAL;
510
511 if ((x->props.flags & XFRM_STATE_ESN) && x->replay_esn)
512 x->repl = &xfrm_replay_esn;
513 else
514 x->repl = &xfrm_replay_bmp;
515 } else
516 x->repl = &xfrm_replay_legacy;
517
518 return 0;
519 }
520 EXPORT_SYMBOL(xfrm_init_replay);
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