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Linux 4.6-rc6
[linux/fpc-iii.git] / net / xfrm / xfrm_replay.c
blob4fd725a0c500ebf69a02e06fcf37ae3035ae0d98
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 <linux/export.h>
22 #include <net/xfrm.h>
23
24 u32 xfrm_replay_seqhi(struct xfrm_state *x, __be32 net_seq)
25 {
26 u32 seq, seq_hi, bottom;
27 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
28
29 if (!(x->props.flags & XFRM_STATE_ESN))
30 return 0;
31
32 seq = ntohl(net_seq);
33 seq_hi = replay_esn->seq_hi;
34 bottom = replay_esn->seq - replay_esn->replay_window + 1;
35
36 if (likely(replay_esn->seq >= replay_esn->replay_window - 1)) {
37 /* A. same subspace */
38 if (unlikely(seq < bottom))
39 seq_hi++;
40 } else {
41 /* B. window spans two subspaces */
42 if (unlikely(seq >= bottom))
43 seq_hi--;
44 }
45
46 return seq_hi;
47 }
48
49 static void xfrm_replay_notify(struct xfrm_state *x, int event)
50 {
51 struct km_event c;
52 /* we send notify messages in case
53 * 1. we updated on of the sequence numbers, and the seqno difference
54 * is at least x->replay_maxdiff, in this case we also update the
55 * timeout of our timer function
56 * 2. if x->replay_maxage has elapsed since last update,
57 * and there were changes
58 *
59 * The state structure must be locked!
60 */
61
62 switch (event) {
63 case XFRM_REPLAY_UPDATE:
64 if (!x->replay_maxdiff ||
65 ((x->replay.seq - x->preplay.seq < x->replay_maxdiff) &&
66 (x->replay.oseq - x->preplay.oseq < x->replay_maxdiff))) {
67 if (x->xflags & XFRM_TIME_DEFER)
68 event = XFRM_REPLAY_TIMEOUT;
69 else
70 return;
71 }
72
73 break;
74
75 case XFRM_REPLAY_TIMEOUT:
76 if (memcmp(&x->replay, &x->preplay,
77 sizeof(struct xfrm_replay_state)) == 0) {
78 x->xflags |= XFRM_TIME_DEFER;
79 return;
80 }
81
82 break;
83 }
84
85 memcpy(&x->preplay, &x->replay, sizeof(struct xfrm_replay_state));
86 c.event = XFRM_MSG_NEWAE;
87 c.data.aevent = event;
88 km_state_notify(x, &c);
89
90 if (x->replay_maxage &&
91 !mod_timer(&x->rtimer, jiffies + x->replay_maxage))
92 x->xflags &= ~XFRM_TIME_DEFER;
93 }
94
95 static int xfrm_replay_overflow(struct xfrm_state *x, struct sk_buff *skb)
96 {
97 int err = 0;
98 struct net *net = xs_net(x);
99
100 if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
101 XFRM_SKB_CB(skb)->seq.output.low = ++x->replay.oseq;
102 XFRM_SKB_CB(skb)->seq.output.hi = 0;
103 if (unlikely(x->replay.oseq == 0)) {
104 x->replay.oseq--;
105 xfrm_audit_state_replay_overflow(x, skb);
106 err = -EOVERFLOW;
107
108 return err;
109 }
110 if (xfrm_aevent_is_on(net))
111 x->repl->notify(x, XFRM_REPLAY_UPDATE);
112 }
113
114 return err;
115 }
116
117 static int xfrm_replay_check(struct xfrm_state *x,
118 struct sk_buff *skb, __be32 net_seq)
119 {
120 u32 diff;
121 u32 seq = ntohl(net_seq);
122
123 if (!x->props.replay_window)
124 return 0;
125
126 if (unlikely(seq == 0))
127 goto err;
128
129 if (likely(seq > x->replay.seq))
130 return 0;
131
132 diff = x->replay.seq - seq;
133 if (diff >= x->props.replay_window) {
134 x->stats.replay_window++;
135 goto err;
136 }
137
138 if (x->replay.bitmap & (1U << diff)) {
139 x->stats.replay++;
140 goto err;
141 }
142 return 0;
143
144 err:
145 xfrm_audit_state_replay(x, skb, net_seq);
146 return -EINVAL;
147 }
148
149 static void xfrm_replay_advance(struct xfrm_state *x, __be32 net_seq)
150 {
151 u32 diff;
152 u32 seq = ntohl(net_seq);
153
154 if (!x->props.replay_window)
155 return;
156
157 if (seq > x->replay.seq) {
158 diff = seq - x->replay.seq;
159 if (diff < x->props.replay_window)
160 x->replay.bitmap = ((x->replay.bitmap) << diff) | 1;
161 else
162 x->replay.bitmap = 1;
163 x->replay.seq = seq;
164 } else {
165 diff = x->replay.seq - seq;
166 x->replay.bitmap |= (1U << diff);
167 }
168
169 if (xfrm_aevent_is_on(xs_net(x)))
170 x->repl->notify(x, XFRM_REPLAY_UPDATE);
171 }
172
173 static int xfrm_replay_overflow_bmp(struct xfrm_state *x, struct sk_buff *skb)
174 {
175 int err = 0;
176 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
177 struct net *net = xs_net(x);
178
179 if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
180 XFRM_SKB_CB(skb)->seq.output.low = ++replay_esn->oseq;
181 XFRM_SKB_CB(skb)->seq.output.hi = 0;
182 if (unlikely(replay_esn->oseq == 0)) {
183 replay_esn->oseq--;
184 xfrm_audit_state_replay_overflow(x, skb);
185 err = -EOVERFLOW;
186
187 return err;
188 }
189 if (xfrm_aevent_is_on(net))
190 x->repl->notify(x, XFRM_REPLAY_UPDATE);
191 }
192
193 return err;
194 }
195
196 static int xfrm_replay_check_bmp(struct xfrm_state *x,
197 struct sk_buff *skb, __be32 net_seq)
198 {
199 unsigned int bitnr, nr;
200 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
201 u32 pos;
202 u32 seq = ntohl(net_seq);
203 u32 diff = replay_esn->seq - seq;
204
205 if (!replay_esn->replay_window)
206 return 0;
207
208 if (unlikely(seq == 0))
209 goto err;
210
211 if (likely(seq > replay_esn->seq))
212 return 0;
213
214 if (diff >= replay_esn->replay_window) {
215 x->stats.replay_window++;
216 goto err;
217 }
218
219 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
220
221 if (pos >= diff)
222 bitnr = (pos - diff) % replay_esn->replay_window;
223 else
224 bitnr = replay_esn->replay_window - (diff - pos);
225
226 nr = bitnr >> 5;
227 bitnr = bitnr & 0x1F;
228 if (replay_esn->bmp[nr] & (1U << bitnr))
229 goto err_replay;
230
231 return 0;
232
233 err_replay:
234 x->stats.replay++;
235 err:
236 xfrm_audit_state_replay(x, skb, net_seq);
237 return -EINVAL;
238 }
239
240 static void xfrm_replay_advance_bmp(struct xfrm_state *x, __be32 net_seq)
241 {
242 unsigned int bitnr, nr, i;
243 u32 diff;
244 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
245 u32 seq = ntohl(net_seq);
246 u32 pos;
247
248 if (!replay_esn->replay_window)
249 return;
250
251 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
252
253 if (seq > replay_esn->seq) {
254 diff = seq - replay_esn->seq;
255
256 if (diff < replay_esn->replay_window) {
257 for (i = 1; i < diff; i++) {
258 bitnr = (pos + i) % replay_esn->replay_window;
259 nr = bitnr >> 5;
260 bitnr = bitnr & 0x1F;
261 replay_esn->bmp[nr] &= ~(1U << bitnr);
262 }
263 } else {
264 nr = (replay_esn->replay_window - 1) >> 5;
265 for (i = 0; i <= nr; i++)
266 replay_esn->bmp[i] = 0;
267 }
268
269 bitnr = (pos + diff) % replay_esn->replay_window;
270 replay_esn->seq = seq;
271 } else {
272 diff = replay_esn->seq - seq;
273
274 if (pos >= diff)
275 bitnr = (pos - diff) % replay_esn->replay_window;
276 else
277 bitnr = replay_esn->replay_window - (diff - pos);
278 }
279
280 nr = bitnr >> 5;
281 bitnr = bitnr & 0x1F;
282 replay_esn->bmp[nr] |= (1U << bitnr);
283
284 if (xfrm_aevent_is_on(xs_net(x)))
285 x->repl->notify(x, XFRM_REPLAY_UPDATE);
286 }
287
288 static void xfrm_replay_notify_bmp(struct xfrm_state *x, int event)
289 {
290 struct km_event c;
291 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
292 struct xfrm_replay_state_esn *preplay_esn = x->preplay_esn;
293
294 /* we send notify messages in case
295 * 1. we updated on of the sequence numbers, and the seqno difference
296 * is at least x->replay_maxdiff, in this case we also update the
297 * timeout of our timer function
298 * 2. if x->replay_maxage has elapsed since last update,
299 * and there were changes
300 *
301 * The state structure must be locked!
302 */
303
304 switch (event) {
305 case XFRM_REPLAY_UPDATE:
306 if (!x->replay_maxdiff ||
307 ((replay_esn->seq - preplay_esn->seq < x->replay_maxdiff) &&
308 (replay_esn->oseq - preplay_esn->oseq
309 < x->replay_maxdiff))) {
310 if (x->xflags & XFRM_TIME_DEFER)
311 event = XFRM_REPLAY_TIMEOUT;
312 else
313 return;
314 }
315
316 break;
317
318 case XFRM_REPLAY_TIMEOUT:
319 if (memcmp(x->replay_esn, x->preplay_esn,
320 xfrm_replay_state_esn_len(replay_esn)) == 0) {
321 x->xflags |= XFRM_TIME_DEFER;
322 return;
323 }
324
325 break;
326 }
327
328 memcpy(x->preplay_esn, x->replay_esn,
329 xfrm_replay_state_esn_len(replay_esn));
330 c.event = XFRM_MSG_NEWAE;
331 c.data.aevent = event;
332 km_state_notify(x, &c);
333
334 if (x->replay_maxage &&
335 !mod_timer(&x->rtimer, jiffies + x->replay_maxage))
336 x->xflags &= ~XFRM_TIME_DEFER;
337 }
338
339 static void xfrm_replay_notify_esn(struct xfrm_state *x, int event)
340 {
341 u32 seq_diff, oseq_diff;
342 struct km_event c;
343 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
344 struct xfrm_replay_state_esn *preplay_esn = x->preplay_esn;
345
346 /* we send notify messages in case
347 * 1. we updated on of the sequence numbers, and the seqno difference
348 * is at least x->replay_maxdiff, in this case we also update the
349 * timeout of our timer function
350 * 2. if x->replay_maxage has elapsed since last update,
351 * and there were changes
352 *
353 * The state structure must be locked!
354 */
355
356 switch (event) {
357 case XFRM_REPLAY_UPDATE:
358 if (x->replay_maxdiff) {
359 if (replay_esn->seq_hi == preplay_esn->seq_hi)
360 seq_diff = replay_esn->seq - preplay_esn->seq;
361 else
362 seq_diff = ~preplay_esn->seq + replay_esn->seq
363 + 1;
364
365 if (replay_esn->oseq_hi == preplay_esn->oseq_hi)
366 oseq_diff = replay_esn->oseq
367 - preplay_esn->oseq;
368 else
369 oseq_diff = ~preplay_esn->oseq
370 + replay_esn->oseq + 1;
371
372 if (seq_diff >= x->replay_maxdiff ||
373 oseq_diff >= x->replay_maxdiff)
374 break;
375 }
376
377 if (x->xflags & XFRM_TIME_DEFER)
378 event = XFRM_REPLAY_TIMEOUT;
379 else
380 return;
381
382 break;
383
384 case XFRM_REPLAY_TIMEOUT:
385 if (memcmp(x->replay_esn, x->preplay_esn,
386 xfrm_replay_state_esn_len(replay_esn)) == 0) {
387 x->xflags |= XFRM_TIME_DEFER;
388 return;
389 }
390
391 break;
392 }
393
394 memcpy(x->preplay_esn, x->replay_esn,
395 xfrm_replay_state_esn_len(replay_esn));
396 c.event = XFRM_MSG_NEWAE;
397 c.data.aevent = event;
398 km_state_notify(x, &c);
399
400 if (x->replay_maxage &&
401 !mod_timer(&x->rtimer, jiffies + x->replay_maxage))
402 x->xflags &= ~XFRM_TIME_DEFER;
403 }
404
405 static int xfrm_replay_overflow_esn(struct xfrm_state *x, struct sk_buff *skb)
406 {
407 int err = 0;
408 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
409 struct net *net = xs_net(x);
410
411 if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
412 XFRM_SKB_CB(skb)->seq.output.low = ++replay_esn->oseq;
413 XFRM_SKB_CB(skb)->seq.output.hi = replay_esn->oseq_hi;
414
415 if (unlikely(replay_esn->oseq == 0)) {
416 XFRM_SKB_CB(skb)->seq.output.hi = ++replay_esn->oseq_hi;
417
418 if (replay_esn->oseq_hi == 0) {
419 replay_esn->oseq--;
420 replay_esn->oseq_hi--;
421 xfrm_audit_state_replay_overflow(x, skb);
422 err = -EOVERFLOW;
423
424 return err;
425 }
426 }
427 if (xfrm_aevent_is_on(net))
428 x->repl->notify(x, XFRM_REPLAY_UPDATE);
429 }
430
431 return err;
432 }
433
434 static int xfrm_replay_check_esn(struct xfrm_state *x,
435 struct sk_buff *skb, __be32 net_seq)
436 {
437 unsigned int bitnr, nr;
438 u32 diff;
439 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
440 u32 pos;
441 u32 seq = ntohl(net_seq);
442 u32 wsize = replay_esn->replay_window;
443 u32 top = replay_esn->seq;
444 u32 bottom = top - wsize + 1;
445
446 if (!wsize)
447 return 0;
448
449 if (unlikely(seq == 0 && replay_esn->seq_hi == 0 &&
450 (replay_esn->seq < replay_esn->replay_window - 1)))
451 goto err;
452
453 diff = top - seq;
454
455 if (likely(top >= wsize - 1)) {
456 /* A. same subspace */
457 if (likely(seq > top) || seq < bottom)
458 return 0;
459 } else {
460 /* B. window spans two subspaces */
461 if (likely(seq > top && seq < bottom))
462 return 0;
463 if (seq >= bottom)
464 diff = ~seq + top + 1;
465 }
466
467 if (diff >= replay_esn->replay_window) {
468 x->stats.replay_window++;
469 goto err;
470 }
471
472 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
473
474 if (pos >= diff)
475 bitnr = (pos - diff) % replay_esn->replay_window;
476 else
477 bitnr = replay_esn->replay_window - (diff - pos);
478
479 nr = bitnr >> 5;
480 bitnr = bitnr & 0x1F;
481 if (replay_esn->bmp[nr] & (1U << bitnr))
482 goto err_replay;
483
484 return 0;
485
486 err_replay:
487 x->stats.replay++;
488 err:
489 xfrm_audit_state_replay(x, skb, net_seq);
490 return -EINVAL;
491 }
492
493 static int xfrm_replay_recheck_esn(struct xfrm_state *x,
494 struct sk_buff *skb, __be32 net_seq)
495 {
496 if (unlikely(XFRM_SKB_CB(skb)->seq.input.hi !=
497 htonl(xfrm_replay_seqhi(x, net_seq)))) {
498 x->stats.replay_window++;
499 return -EINVAL;
500 }
501
502 return xfrm_replay_check_esn(x, skb, net_seq);
503 }
504
505 static void xfrm_replay_advance_esn(struct xfrm_state *x, __be32 net_seq)
506 {
507 unsigned int bitnr, nr, i;
508 int wrap;
509 u32 diff, pos, seq, seq_hi;
510 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
511
512 if (!replay_esn->replay_window)
513 return;
514
515 seq = ntohl(net_seq);
516 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
517 seq_hi = xfrm_replay_seqhi(x, net_seq);
518 wrap = seq_hi - replay_esn->seq_hi;
519
520 if ((!wrap && seq > replay_esn->seq) || wrap > 0) {
521 if (likely(!wrap))
522 diff = seq - replay_esn->seq;
523 else
524 diff = ~replay_esn->seq + seq + 1;
525
526 if (diff < replay_esn->replay_window) {
527 for (i = 1; i < diff; i++) {
528 bitnr = (pos + i) % replay_esn->replay_window;
529 nr = bitnr >> 5;
530 bitnr = bitnr & 0x1F;
531 replay_esn->bmp[nr] &= ~(1U << bitnr);
532 }
533 } else {
534 nr = (replay_esn->replay_window - 1) >> 5;
535 for (i = 0; i <= nr; i++)
536 replay_esn->bmp[i] = 0;
537 }
538
539 bitnr = (pos + diff) % replay_esn->replay_window;
540 replay_esn->seq = seq;
541
542 if (unlikely(wrap > 0))
543 replay_esn->seq_hi++;
544 } else {
545 diff = replay_esn->seq - seq;
546
547 if (pos >= diff)
548 bitnr = (pos - diff) % replay_esn->replay_window;
549 else
550 bitnr = replay_esn->replay_window - (diff - pos);
551 }
552
553 nr = bitnr >> 5;
554 bitnr = bitnr & 0x1F;
555 replay_esn->bmp[nr] |= (1U << bitnr);
556
557 if (xfrm_aevent_is_on(xs_net(x)))
558 x->repl->notify(x, XFRM_REPLAY_UPDATE);
559 }
560
561 static struct xfrm_replay xfrm_replay_legacy = {
562 .advance = xfrm_replay_advance,
563 .check = xfrm_replay_check,
564 .recheck = xfrm_replay_check,
565 .notify = xfrm_replay_notify,
566 .overflow = xfrm_replay_overflow,
567 };
568
569 static struct xfrm_replay xfrm_replay_bmp = {
570 .advance = xfrm_replay_advance_bmp,
571 .check = xfrm_replay_check_bmp,
572 .recheck = xfrm_replay_check_bmp,
573 .notify = xfrm_replay_notify_bmp,
574 .overflow = xfrm_replay_overflow_bmp,
575 };
576
577 static struct xfrm_replay xfrm_replay_esn = {
578 .advance = xfrm_replay_advance_esn,
579 .check = xfrm_replay_check_esn,
580 .recheck = xfrm_replay_recheck_esn,
581 .notify = xfrm_replay_notify_esn,
582 .overflow = xfrm_replay_overflow_esn,
583 };
584
585 int xfrm_init_replay(struct xfrm_state *x)
586 {
587 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
588
589 if (replay_esn) {
590 if (replay_esn->replay_window >
591 replay_esn->bmp_len * sizeof(__u32) * 8)
592 return -EINVAL;
593
594 if (x->props.flags & XFRM_STATE_ESN) {
595 if (replay_esn->replay_window == 0)
596 return -EINVAL;
597 x->repl = &xfrm_replay_esn;
598 } else
599 x->repl = &xfrm_replay_bmp;
600 } else
601 x->repl = &xfrm_replay_legacy;
602
603 return 0;
604 }
605 EXPORT_SYMBOL(xfrm_init_replay);
Linux with added FPC-III support