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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * xfrm_replay.c - xfrm replay detection, derived from xfrm_state.c.
4 *
5 * Copyright (C) 2010 secunet Security Networks AG
6 * Copyright (C) 2010 Steffen Klassert <steffen.klassert@secunet.com>
7 */
8
9#include <linux/export.h>
10#include <net/xfrm.h>
11
12u32 xfrm_replay_seqhi(struct xfrm_state *x, __be32 net_seq)
13{
14 u32 seq, seq_hi, bottom;
15 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
16
17 if (!(x->props.flags & XFRM_STATE_ESN))
18 return 0;
19
20 seq = ntohl(net_seq);
21 seq_hi = replay_esn->seq_hi;
22 bottom = replay_esn->seq - replay_esn->replay_window + 1;
23
24 if (likely(replay_esn->seq >= replay_esn->replay_window - 1)) {
25 /* A. same subspace */
26 if (unlikely(seq < bottom))
27 seq_hi++;
28 } else {
29 /* B. window spans two subspaces */
30 if (unlikely(seq >= bottom))
31 seq_hi--;
32 }
33
34 return seq_hi;
35}
36EXPORT_SYMBOL(xfrm_replay_seqhi);
37;
38static void xfrm_replay_notify(struct xfrm_state *x, int event)
39{
40 struct km_event c;
41 /* we send notify messages in case
42 * 1. we updated on of the sequence numbers, and the seqno difference
43 * is at least x->replay_maxdiff, in this case we also update the
44 * timeout of our timer function
45 * 2. if x->replay_maxage has elapsed since last update,
46 * and there were changes
47 *
48 * The state structure must be locked!
49 */
50
51 switch (event) {
52 case XFRM_REPLAY_UPDATE:
53 if (!x->replay_maxdiff ||
54 ((x->replay.seq - x->preplay.seq < x->replay_maxdiff) &&
55 (x->replay.oseq - x->preplay.oseq < x->replay_maxdiff))) {
56 if (x->xflags & XFRM_TIME_DEFER)
57 event = XFRM_REPLAY_TIMEOUT;
58 else
59 return;
60 }
61
62 break;
63
64 case XFRM_REPLAY_TIMEOUT:
65 if (memcmp(&x->replay, &x->preplay,
66 sizeof(struct xfrm_replay_state)) == 0) {
67 x->xflags |= XFRM_TIME_DEFER;
68 return;
69 }
70
71 break;
72 }
73
74 memcpy(&x->preplay, &x->replay, sizeof(struct xfrm_replay_state));
75 c.event = XFRM_MSG_NEWAE;
76 c.data.aevent = event;
77 km_state_notify(x, &c);
78
79 if (x->replay_maxage &&
80 !mod_timer(&x->rtimer, jiffies + x->replay_maxage))
81 x->xflags &= ~XFRM_TIME_DEFER;
82}
83
84static int xfrm_replay_overflow(struct xfrm_state *x, struct sk_buff *skb)
85{
86 int err = 0;
87 struct net *net = xs_net(x);
88
89 if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
90 XFRM_SKB_CB(skb)->seq.output.low = ++x->replay.oseq;
91 XFRM_SKB_CB(skb)->seq.output.hi = 0;
92 if (unlikely(x->replay.oseq == 0)) {
93 x->replay.oseq--;
94 xfrm_audit_state_replay_overflow(x, skb);
95 err = -EOVERFLOW;
96
97 return err;
98 }
99 if (xfrm_aevent_is_on(net))
100 x->repl->notify(x, XFRM_REPLAY_UPDATE);
101 }
102
103 return err;
104}
105
106static int xfrm_replay_check(struct xfrm_state *x,
107 struct sk_buff *skb, __be32 net_seq)
108{
109 u32 diff;
110 u32 seq = ntohl(net_seq);
111
112 if (!x->props.replay_window)
113 return 0;
114
115 if (unlikely(seq == 0))
116 goto err;
117
118 if (likely(seq > x->replay.seq))
119 return 0;
120
121 diff = x->replay.seq - seq;
122 if (diff >= x->props.replay_window) {
123 x->stats.replay_window++;
124 goto err;
125 }
126
127 if (x->replay.bitmap & (1U << diff)) {
128 x->stats.replay++;
129 goto err;
130 }
131 return 0;
132
133err:
134 xfrm_audit_state_replay(x, skb, net_seq);
135 return -EINVAL;
136}
137
138static void xfrm_replay_advance(struct xfrm_state *x, __be32 net_seq)
139{
140 u32 diff;
141 u32 seq = ntohl(net_seq);
142
143 if (!x->props.replay_window)
144 return;
145
146 if (seq > x->replay.seq) {
147 diff = seq - x->replay.seq;
148 if (diff < x->props.replay_window)
149 x->replay.bitmap = ((x->replay.bitmap) << diff) | 1;
150 else
151 x->replay.bitmap = 1;
152 x->replay.seq = seq;
153 } else {
154 diff = x->replay.seq - seq;
155 x->replay.bitmap |= (1U << diff);
156 }
157
158 if (xfrm_aevent_is_on(xs_net(x)))
159 x->repl->notify(x, XFRM_REPLAY_UPDATE);
160}
161
162static int xfrm_replay_overflow_bmp(struct xfrm_state *x, struct sk_buff *skb)
163{
164 int err = 0;
165 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
166 struct net *net = xs_net(x);
167
168 if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
169 XFRM_SKB_CB(skb)->seq.output.low = ++replay_esn->oseq;
170 XFRM_SKB_CB(skb)->seq.output.hi = 0;
171 if (unlikely(replay_esn->oseq == 0)) {
172 replay_esn->oseq--;
173 xfrm_audit_state_replay_overflow(x, skb);
174 err = -EOVERFLOW;
175
176 return err;
177 }
178 if (xfrm_aevent_is_on(net))
179 x->repl->notify(x, XFRM_REPLAY_UPDATE);
180 }
181
182 return err;
183}
184
185static int xfrm_replay_check_bmp(struct xfrm_state *x,
186 struct sk_buff *skb, __be32 net_seq)
187{
188 unsigned int bitnr, nr;
189 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
190 u32 pos;
191 u32 seq = ntohl(net_seq);
192 u32 diff = replay_esn->seq - seq;
193
194 if (!replay_esn->replay_window)
195 return 0;
196
197 if (unlikely(seq == 0))
198 goto err;
199
200 if (likely(seq > replay_esn->seq))
201 return 0;
202
203 if (diff >= replay_esn->replay_window) {
204 x->stats.replay_window++;
205 goto err;
206 }
207
208 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
209
210 if (pos >= diff)
211 bitnr = (pos - diff) % replay_esn->replay_window;
212 else
213 bitnr = replay_esn->replay_window - (diff - pos);
214
215 nr = bitnr >> 5;
216 bitnr = bitnr & 0x1F;
217 if (replay_esn->bmp[nr] & (1U << bitnr))
218 goto err_replay;
219
220 return 0;
221
222err_replay:
223 x->stats.replay++;
224err:
225 xfrm_audit_state_replay(x, skb, net_seq);
226 return -EINVAL;
227}
228
229static void xfrm_replay_advance_bmp(struct xfrm_state *x, __be32 net_seq)
230{
231 unsigned int bitnr, nr, i;
232 u32 diff;
233 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
234 u32 seq = ntohl(net_seq);
235 u32 pos;
236
237 if (!replay_esn->replay_window)
238 return;
239
240 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
241
242 if (seq > replay_esn->seq) {
243 diff = seq - replay_esn->seq;
244
245 if (diff < replay_esn->replay_window) {
246 for (i = 1; i < diff; i++) {
247 bitnr = (pos + i) % replay_esn->replay_window;
248 nr = bitnr >> 5;
249 bitnr = bitnr & 0x1F;
250 replay_esn->bmp[nr] &= ~(1U << bitnr);
251 }
252 } else {
253 nr = (replay_esn->replay_window - 1) >> 5;
254 for (i = 0; i <= nr; i++)
255 replay_esn->bmp[i] = 0;
256 }
257
258 bitnr = (pos + diff) % replay_esn->replay_window;
259 replay_esn->seq = seq;
260 } else {
261 diff = replay_esn->seq - seq;
262
263 if (pos >= diff)
264 bitnr = (pos - diff) % replay_esn->replay_window;
265 else
266 bitnr = replay_esn->replay_window - (diff - pos);
267 }
268
269 nr = bitnr >> 5;
270 bitnr = bitnr & 0x1F;
271 replay_esn->bmp[nr] |= (1U << bitnr);
272
273 if (xfrm_aevent_is_on(xs_net(x)))
274 x->repl->notify(x, XFRM_REPLAY_UPDATE);
275}
276
277static void xfrm_replay_notify_bmp(struct xfrm_state *x, int event)
278{
279 struct km_event c;
280 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
281 struct xfrm_replay_state_esn *preplay_esn = x->preplay_esn;
282
283 /* we send notify messages in case
284 * 1. we updated on of the sequence numbers, and the seqno difference
285 * is at least x->replay_maxdiff, in this case we also update the
286 * timeout of our timer function
287 * 2. if x->replay_maxage has elapsed since last update,
288 * and there were changes
289 *
290 * The state structure must be locked!
291 */
292
293 switch (event) {
294 case XFRM_REPLAY_UPDATE:
295 if (!x->replay_maxdiff ||
296 ((replay_esn->seq - preplay_esn->seq < x->replay_maxdiff) &&
297 (replay_esn->oseq - preplay_esn->oseq
298 < x->replay_maxdiff))) {
299 if (x->xflags & XFRM_TIME_DEFER)
300 event = XFRM_REPLAY_TIMEOUT;
301 else
302 return;
303 }
304
305 break;
306
307 case XFRM_REPLAY_TIMEOUT:
308 if (memcmp(x->replay_esn, x->preplay_esn,
309 xfrm_replay_state_esn_len(replay_esn)) == 0) {
310 x->xflags |= XFRM_TIME_DEFER;
311 return;
312 }
313
314 break;
315 }
316
317 memcpy(x->preplay_esn, x->replay_esn,
318 xfrm_replay_state_esn_len(replay_esn));
319 c.event = XFRM_MSG_NEWAE;
320 c.data.aevent = event;
321 km_state_notify(x, &c);
322
323 if (x->replay_maxage &&
324 !mod_timer(&x->rtimer, jiffies + x->replay_maxage))
325 x->xflags &= ~XFRM_TIME_DEFER;
326}
327
328static void xfrm_replay_notify_esn(struct xfrm_state *x, int event)
329{
330 u32 seq_diff, oseq_diff;
331 struct km_event c;
332 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
333 struct xfrm_replay_state_esn *preplay_esn = x->preplay_esn;
334
335 /* we send notify messages in case
336 * 1. we updated on of the sequence numbers, and the seqno difference
337 * is at least x->replay_maxdiff, in this case we also update the
338 * timeout of our timer function
339 * 2. if x->replay_maxage has elapsed since last update,
340 * and there were changes
341 *
342 * The state structure must be locked!
343 */
344
345 switch (event) {
346 case XFRM_REPLAY_UPDATE:
347 if (x->replay_maxdiff) {
348 if (replay_esn->seq_hi == preplay_esn->seq_hi)
349 seq_diff = replay_esn->seq - preplay_esn->seq;
350 else
351 seq_diff = ~preplay_esn->seq + replay_esn->seq
352 + 1;
353
354 if (replay_esn->oseq_hi == preplay_esn->oseq_hi)
355 oseq_diff = replay_esn->oseq
356 - preplay_esn->oseq;
357 else
358 oseq_diff = ~preplay_esn->oseq
359 + replay_esn->oseq + 1;
360
361 if (seq_diff >= x->replay_maxdiff ||
362 oseq_diff >= x->replay_maxdiff)
363 break;
364 }
365
366 if (x->xflags & XFRM_TIME_DEFER)
367 event = XFRM_REPLAY_TIMEOUT;
368 else
369 return;
370
371 break;
372
373 case XFRM_REPLAY_TIMEOUT:
374 if (memcmp(x->replay_esn, x->preplay_esn,
375 xfrm_replay_state_esn_len(replay_esn)) == 0) {
376 x->xflags |= XFRM_TIME_DEFER;
377 return;
378 }
379
380 break;
381 }
382
383 memcpy(x->preplay_esn, x->replay_esn,
384 xfrm_replay_state_esn_len(replay_esn));
385 c.event = XFRM_MSG_NEWAE;
386 c.data.aevent = event;
387 km_state_notify(x, &c);
388
389 if (x->replay_maxage &&
390 !mod_timer(&x->rtimer, jiffies + x->replay_maxage))
391 x->xflags &= ~XFRM_TIME_DEFER;
392}
393
394static int xfrm_replay_overflow_esn(struct xfrm_state *x, struct sk_buff *skb)
395{
396 int err = 0;
397 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
398 struct net *net = xs_net(x);
399
400 if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
401 XFRM_SKB_CB(skb)->seq.output.low = ++replay_esn->oseq;
402 XFRM_SKB_CB(skb)->seq.output.hi = replay_esn->oseq_hi;
403
404 if (unlikely(replay_esn->oseq == 0)) {
405 XFRM_SKB_CB(skb)->seq.output.hi = ++replay_esn->oseq_hi;
406
407 if (replay_esn->oseq_hi == 0) {
408 replay_esn->oseq--;
409 replay_esn->oseq_hi--;
410 xfrm_audit_state_replay_overflow(x, skb);
411 err = -EOVERFLOW;
412
413 return err;
414 }
415 }
416 if (xfrm_aevent_is_on(net))
417 x->repl->notify(x, XFRM_REPLAY_UPDATE);
418 }
419
420 return err;
421}
422
423static int xfrm_replay_check_esn(struct xfrm_state *x,
424 struct sk_buff *skb, __be32 net_seq)
425{
426 unsigned int bitnr, nr;
427 u32 diff;
428 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
429 u32 pos;
430 u32 seq = ntohl(net_seq);
431 u32 wsize = replay_esn->replay_window;
432 u32 top = replay_esn->seq;
433 u32 bottom = top - wsize + 1;
434
435 if (!wsize)
436 return 0;
437
438 if (unlikely(seq == 0 && replay_esn->seq_hi == 0 &&
439 (replay_esn->seq < replay_esn->replay_window - 1)))
440 goto err;
441
442 diff = top - seq;
443
444 if (likely(top >= wsize - 1)) {
445 /* A. same subspace */
446 if (likely(seq > top) || seq < bottom)
447 return 0;
448 } else {
449 /* B. window spans two subspaces */
450 if (likely(seq > top && seq < bottom))
451 return 0;
452 if (seq >= bottom)
453 diff = ~seq + top + 1;
454 }
455
456 if (diff >= replay_esn->replay_window) {
457 x->stats.replay_window++;
458 goto err;
459 }
460
461 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
462
463 if (pos >= diff)
464 bitnr = (pos - diff) % replay_esn->replay_window;
465 else
466 bitnr = replay_esn->replay_window - (diff - pos);
467
468 nr = bitnr >> 5;
469 bitnr = bitnr & 0x1F;
470 if (replay_esn->bmp[nr] & (1U << bitnr))
471 goto err_replay;
472
473 return 0;
474
475err_replay:
476 x->stats.replay++;
477err:
478 xfrm_audit_state_replay(x, skb, net_seq);
479 return -EINVAL;
480}
481
482static int xfrm_replay_recheck_esn(struct xfrm_state *x,
483 struct sk_buff *skb, __be32 net_seq)
484{
485 if (unlikely(XFRM_SKB_CB(skb)->seq.input.hi !=
486 htonl(xfrm_replay_seqhi(x, net_seq)))) {
487 x->stats.replay_window++;
488 return -EINVAL;
489 }
490
491 return xfrm_replay_check_esn(x, skb, net_seq);
492}
493
494static void xfrm_replay_advance_esn(struct xfrm_state *x, __be32 net_seq)
495{
496 unsigned int bitnr, nr, i;
497 int wrap;
498 u32 diff, pos, seq, seq_hi;
499 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
500
501 if (!replay_esn->replay_window)
502 return;
503
504 seq = ntohl(net_seq);
505 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
506 seq_hi = xfrm_replay_seqhi(x, net_seq);
507 wrap = seq_hi - replay_esn->seq_hi;
508
509 if ((!wrap && seq > replay_esn->seq) || wrap > 0) {
510 if (likely(!wrap))
511 diff = seq - replay_esn->seq;
512 else
513 diff = ~replay_esn->seq + seq + 1;
514
515 if (diff < replay_esn->replay_window) {
516 for (i = 1; i < diff; i++) {
517 bitnr = (pos + i) % replay_esn->replay_window;
518 nr = bitnr >> 5;
519 bitnr = bitnr & 0x1F;
520 replay_esn->bmp[nr] &= ~(1U << bitnr);
521 }
522 } else {
523 nr = (replay_esn->replay_window - 1) >> 5;
524 for (i = 0; i <= nr; i++)
525 replay_esn->bmp[i] = 0;
526 }
527
528 bitnr = (pos + diff) % replay_esn->replay_window;
529 replay_esn->seq = seq;
530
531 if (unlikely(wrap > 0))
532 replay_esn->seq_hi++;
533 } else {
534 diff = replay_esn->seq - seq;
535
536 if (pos >= diff)
537 bitnr = (pos - diff) % replay_esn->replay_window;
538 else
539 bitnr = replay_esn->replay_window - (diff - pos);
540 }
541
542 xfrm_dev_state_advance_esn(x);
543
544 nr = bitnr >> 5;
545 bitnr = bitnr & 0x1F;
546 replay_esn->bmp[nr] |= (1U << bitnr);
547
548 if (xfrm_aevent_is_on(xs_net(x)))
549 x->repl->notify(x, XFRM_REPLAY_UPDATE);
550}
551
552#ifdef CONFIG_XFRM_OFFLOAD
553static int xfrm_replay_overflow_offload(struct xfrm_state *x, struct sk_buff *skb)
554{
555 int err = 0;
556 struct net *net = xs_net(x);
557 struct xfrm_offload *xo = xfrm_offload(skb);
558 __u32 oseq = x->replay.oseq;
559
560 if (!xo)
561 return xfrm_replay_overflow(x, skb);
562
563 if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
564 if (!skb_is_gso(skb)) {
565 XFRM_SKB_CB(skb)->seq.output.low = ++oseq;
566 xo->seq.low = oseq;
567 } else {
568 XFRM_SKB_CB(skb)->seq.output.low = oseq + 1;
569 xo->seq.low = oseq + 1;
570 oseq += skb_shinfo(skb)->gso_segs;
571 }
572
573 XFRM_SKB_CB(skb)->seq.output.hi = 0;
574 xo->seq.hi = 0;
575 if (unlikely(oseq < x->replay.oseq)) {
576 xfrm_audit_state_replay_overflow(x, skb);
577 err = -EOVERFLOW;
578
579 return err;
580 }
581
582 x->replay.oseq = oseq;
583
584 if (xfrm_aevent_is_on(net))
585 x->repl->notify(x, XFRM_REPLAY_UPDATE);
586 }
587
588 return err;
589}
590
591static int xfrm_replay_overflow_offload_bmp(struct xfrm_state *x, struct sk_buff *skb)
592{
593 int err = 0;
594 struct xfrm_offload *xo = xfrm_offload(skb);
595 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
596 struct net *net = xs_net(x);
597 __u32 oseq = replay_esn->oseq;
598
599 if (!xo)
600 return xfrm_replay_overflow_bmp(x, skb);
601
602 if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
603 if (!skb_is_gso(skb)) {
604 XFRM_SKB_CB(skb)->seq.output.low = ++oseq;
605 xo->seq.low = oseq;
606 } else {
607 XFRM_SKB_CB(skb)->seq.output.low = oseq + 1;
608 xo->seq.low = oseq + 1;
609 oseq += skb_shinfo(skb)->gso_segs;
610 }
611
612 XFRM_SKB_CB(skb)->seq.output.hi = 0;
613 xo->seq.hi = 0;
614 if (unlikely(oseq < replay_esn->oseq)) {
615 xfrm_audit_state_replay_overflow(x, skb);
616 err = -EOVERFLOW;
617
618 return err;
619 } else {
620 replay_esn->oseq = oseq;
621 }
622
623 if (xfrm_aevent_is_on(net))
624 x->repl->notify(x, XFRM_REPLAY_UPDATE);
625 }
626
627 return err;
628}
629
630static int xfrm_replay_overflow_offload_esn(struct xfrm_state *x, struct sk_buff *skb)
631{
632 int err = 0;
633 struct xfrm_offload *xo = xfrm_offload(skb);
634 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
635 struct net *net = xs_net(x);
636 __u32 oseq = replay_esn->oseq;
637 __u32 oseq_hi = replay_esn->oseq_hi;
638
639 if (!xo)
640 return xfrm_replay_overflow_esn(x, skb);
641
642 if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
643 if (!skb_is_gso(skb)) {
644 XFRM_SKB_CB(skb)->seq.output.low = ++oseq;
645 XFRM_SKB_CB(skb)->seq.output.hi = oseq_hi;
646 xo->seq.low = oseq;
647 xo->seq.hi = oseq_hi;
648 } else {
649 XFRM_SKB_CB(skb)->seq.output.low = oseq + 1;
650 XFRM_SKB_CB(skb)->seq.output.hi = oseq_hi;
651 xo->seq.low = oseq + 1;
652 xo->seq.hi = oseq_hi;
653 oseq += skb_shinfo(skb)->gso_segs;
654 }
655
656 if (unlikely(oseq < replay_esn->oseq)) {
657 XFRM_SKB_CB(skb)->seq.output.hi = ++oseq_hi;
658 xo->seq.hi = oseq_hi;
659 replay_esn->oseq_hi = oseq_hi;
660 if (replay_esn->oseq_hi == 0) {
661 replay_esn->oseq--;
662 replay_esn->oseq_hi--;
663 xfrm_audit_state_replay_overflow(x, skb);
664 err = -EOVERFLOW;
665
666 return err;
667 }
668 }
669
670 replay_esn->oseq = oseq;
671
672 if (xfrm_aevent_is_on(net))
673 x->repl->notify(x, XFRM_REPLAY_UPDATE);
674 }
675
676 return err;
677}
678
679static const struct xfrm_replay xfrm_replay_legacy = {
680 .advance = xfrm_replay_advance,
681 .check = xfrm_replay_check,
682 .recheck = xfrm_replay_check,
683 .notify = xfrm_replay_notify,
684 .overflow = xfrm_replay_overflow_offload,
685};
686
687static const struct xfrm_replay xfrm_replay_bmp = {
688 .advance = xfrm_replay_advance_bmp,
689 .check = xfrm_replay_check_bmp,
690 .recheck = xfrm_replay_check_bmp,
691 .notify = xfrm_replay_notify_bmp,
692 .overflow = xfrm_replay_overflow_offload_bmp,
693};
694
695static const struct xfrm_replay xfrm_replay_esn = {
696 .advance = xfrm_replay_advance_esn,
697 .check = xfrm_replay_check_esn,
698 .recheck = xfrm_replay_recheck_esn,
699 .notify = xfrm_replay_notify_esn,
700 .overflow = xfrm_replay_overflow_offload_esn,
701};
702#else
703static const struct xfrm_replay xfrm_replay_legacy = {
704 .advance = xfrm_replay_advance,
705 .check = xfrm_replay_check,
706 .recheck = xfrm_replay_check,
707 .notify = xfrm_replay_notify,
708 .overflow = xfrm_replay_overflow,
709};
710
711static const struct xfrm_replay xfrm_replay_bmp = {
712 .advance = xfrm_replay_advance_bmp,
713 .check = xfrm_replay_check_bmp,
714 .recheck = xfrm_replay_check_bmp,
715 .notify = xfrm_replay_notify_bmp,
716 .overflow = xfrm_replay_overflow_bmp,
717};
718
719static const struct xfrm_replay xfrm_replay_esn = {
720 .advance = xfrm_replay_advance_esn,
721 .check = xfrm_replay_check_esn,
722 .recheck = xfrm_replay_recheck_esn,
723 .notify = xfrm_replay_notify_esn,
724 .overflow = xfrm_replay_overflow_esn,
725};
726#endif
727
728int xfrm_init_replay(struct xfrm_state *x)
729{
730 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
731
732 if (replay_esn) {
733 if (replay_esn->replay_window >
734 replay_esn->bmp_len * sizeof(__u32) * 8)
735 return -EINVAL;
736
737 if (x->props.flags & XFRM_STATE_ESN) {
738 if (replay_esn->replay_window == 0)
739 return -EINVAL;
740 x->repl = &xfrm_replay_esn;
741 } else {
742 x->repl = &xfrm_replay_bmp;
743 }
744 } else {
745 x->repl = &xfrm_replay_legacy;
746 }
747
748 return 0;
749}
750EXPORT_SYMBOL(xfrm_init_replay);
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
23u32 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
48static 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
94static 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
115static 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
143err:
144 xfrm_audit_state_replay(x, skb, net_seq);
145 return -EINVAL;
146}
147
148static 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
172static 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
194static 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 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
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 if (pos >= diff) {
220 bitnr = (pos - diff) % replay_esn->replay_window;
221 nr = bitnr >> 5;
222 bitnr = bitnr & 0x1F;
223 if (replay_esn->bmp[nr] & (1U << bitnr))
224 goto err_replay;
225 } else {
226 bitnr = replay_esn->replay_window - (diff - pos);
227 nr = bitnr >> 5;
228 bitnr = bitnr & 0x1F;
229 if (replay_esn->bmp[nr] & (1U << bitnr))
230 goto err_replay;
231 }
232 return 0;
233
234err_replay:
235 x->stats.replay++;
236err:
237 xfrm_audit_state_replay(x, skb, net_seq);
238 return -EINVAL;
239}
240
241static void xfrm_replay_advance_bmp(struct xfrm_state *x, __be32 net_seq)
242{
243 unsigned int bitnr, nr, i;
244 u32 diff;
245 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
246 u32 seq = ntohl(net_seq);
247 u32 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
248
249 if (!replay_esn->replay_window)
250 return;
251
252 if (seq > replay_esn->seq) {
253 diff = seq - replay_esn->seq;
254
255 if (diff < replay_esn->replay_window) {
256 for (i = 1; i < diff; i++) {
257 bitnr = (pos + i) % replay_esn->replay_window;
258 nr = bitnr >> 5;
259 bitnr = bitnr & 0x1F;
260 replay_esn->bmp[nr] &= ~(1U << bitnr);
261 }
262
263 bitnr = (pos + diff) % replay_esn->replay_window;
264 nr = bitnr >> 5;
265 bitnr = bitnr & 0x1F;
266 replay_esn->bmp[nr] |= (1U << bitnr);
267 } else {
268 nr = (replay_esn->replay_window - 1) >> 5;
269 for (i = 0; i <= nr; i++)
270 replay_esn->bmp[i] = 0;
271
272 bitnr = (pos + diff) % replay_esn->replay_window;
273 nr = bitnr >> 5;
274 bitnr = bitnr & 0x1F;
275 replay_esn->bmp[nr] |= (1U << bitnr);
276 }
277
278 replay_esn->seq = seq;
279 } else {
280 diff = replay_esn->seq - seq;
281
282 if (pos >= diff) {
283 bitnr = (pos - diff) % replay_esn->replay_window;
284 nr = bitnr >> 5;
285 bitnr = bitnr & 0x1F;
286 replay_esn->bmp[nr] |= (1U << bitnr);
287 } else {
288 bitnr = replay_esn->replay_window - (diff - pos);
289 nr = bitnr >> 5;
290 bitnr = bitnr & 0x1F;
291 replay_esn->bmp[nr] |= (1U << bitnr);
292 }
293 }
294
295 if (xfrm_aevent_is_on(xs_net(x)))
296 xfrm_replay_notify(x, XFRM_REPLAY_UPDATE);
297}
298
299static void xfrm_replay_notify_bmp(struct xfrm_state *x, int event)
300{
301 struct km_event c;
302 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
303 struct xfrm_replay_state_esn *preplay_esn = x->preplay_esn;
304
305 /* we send notify messages in case
306 * 1. we updated on of the sequence numbers, and the seqno difference
307 * is at least x->replay_maxdiff, in this case we also update the
308 * timeout of our timer function
309 * 2. if x->replay_maxage has elapsed since last update,
310 * and there were changes
311 *
312 * The state structure must be locked!
313 */
314
315 switch (event) {
316 case XFRM_REPLAY_UPDATE:
317 if (x->replay_maxdiff &&
318 (replay_esn->seq - preplay_esn->seq < x->replay_maxdiff) &&
319 (replay_esn->oseq - preplay_esn->oseq < x->replay_maxdiff)) {
320 if (x->xflags & XFRM_TIME_DEFER)
321 event = XFRM_REPLAY_TIMEOUT;
322 else
323 return;
324 }
325
326 break;
327
328 case XFRM_REPLAY_TIMEOUT:
329 if (memcmp(x->replay_esn, x->preplay_esn,
330 xfrm_replay_state_esn_len(replay_esn)) == 0) {
331 x->xflags |= XFRM_TIME_DEFER;
332 return;
333 }
334
335 break;
336 }
337
338 memcpy(x->preplay_esn, x->replay_esn,
339 xfrm_replay_state_esn_len(replay_esn));
340 c.event = XFRM_MSG_NEWAE;
341 c.data.aevent = event;
342 km_state_notify(x, &c);
343
344 if (x->replay_maxage &&
345 !mod_timer(&x->rtimer, jiffies + x->replay_maxage))
346 x->xflags &= ~XFRM_TIME_DEFER;
347}
348
349static int xfrm_replay_overflow_esn(struct xfrm_state *x, struct sk_buff *skb)
350{
351 int err = 0;
352 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
353 struct net *net = xs_net(x);
354
355 if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
356 XFRM_SKB_CB(skb)->seq.output.low = ++replay_esn->oseq;
357 XFRM_SKB_CB(skb)->seq.output.hi = replay_esn->oseq_hi;
358
359 if (unlikely(replay_esn->oseq == 0)) {
360 XFRM_SKB_CB(skb)->seq.output.hi = ++replay_esn->oseq_hi;
361
362 if (replay_esn->oseq_hi == 0) {
363 replay_esn->oseq--;
364 replay_esn->oseq_hi--;
365 xfrm_audit_state_replay_overflow(x, skb);
366 err = -EOVERFLOW;
367
368 return err;
369 }
370 }
371 if (xfrm_aevent_is_on(net))
372 x->repl->notify(x, XFRM_REPLAY_UPDATE);
373 }
374
375 return err;
376}
377
378static int xfrm_replay_check_esn(struct xfrm_state *x,
379 struct sk_buff *skb, __be32 net_seq)
380{
381 unsigned int bitnr, nr;
382 u32 diff;
383 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
384 u32 pos;
385 u32 seq = ntohl(net_seq);
386 u32 wsize = replay_esn->replay_window;
387 u32 top = replay_esn->seq;
388 u32 bottom = top - wsize + 1;
389
390 if (!wsize)
391 return 0;
392
393 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
394
395 if (unlikely(seq == 0 && replay_esn->seq_hi == 0 &&
396 (replay_esn->seq < replay_esn->replay_window - 1)))
397 goto err;
398
399 diff = top - seq;
400
401 if (likely(top >= wsize - 1)) {
402 /* A. same subspace */
403 if (likely(seq > top) || seq < bottom)
404 return 0;
405 } else {
406 /* B. window spans two subspaces */
407 if (likely(seq > top && seq < bottom))
408 return 0;
409 if (seq >= bottom)
410 diff = ~seq + top + 1;
411 }
412
413 if (diff >= replay_esn->replay_window) {
414 x->stats.replay_window++;
415 goto err;
416 }
417
418 if (pos >= diff) {
419 bitnr = (pos - diff) % replay_esn->replay_window;
420 nr = bitnr >> 5;
421 bitnr = bitnr & 0x1F;
422 if (replay_esn->bmp[nr] & (1U << bitnr))
423 goto err_replay;
424 } else {
425 bitnr = replay_esn->replay_window - (diff - pos);
426 nr = bitnr >> 5;
427 bitnr = bitnr & 0x1F;
428 if (replay_esn->bmp[nr] & (1U << bitnr))
429 goto err_replay;
430 }
431 return 0;
432
433err_replay:
434 x->stats.replay++;
435err:
436 xfrm_audit_state_replay(x, skb, net_seq);
437 return -EINVAL;
438}
439
440static void xfrm_replay_advance_esn(struct xfrm_state *x, __be32 net_seq)
441{
442 unsigned int bitnr, nr, i;
443 int wrap;
444 u32 diff, pos, seq, seq_hi;
445 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
446
447 if (!replay_esn->replay_window)
448 return;
449
450 seq = ntohl(net_seq);
451 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
452 seq_hi = xfrm_replay_seqhi(x, net_seq);
453 wrap = seq_hi - replay_esn->seq_hi;
454
455 if ((!wrap && seq > replay_esn->seq) || wrap > 0) {
456 if (likely(!wrap))
457 diff = seq - replay_esn->seq;
458 else
459 diff = ~replay_esn->seq + seq + 1;
460
461 if (diff < replay_esn->replay_window) {
462 for (i = 1; i < diff; i++) {
463 bitnr = (pos + i) % replay_esn->replay_window;
464 nr = bitnr >> 5;
465 bitnr = bitnr & 0x1F;
466 replay_esn->bmp[nr] &= ~(1U << bitnr);
467 }
468
469 bitnr = (pos + diff) % replay_esn->replay_window;
470 nr = bitnr >> 5;
471 bitnr = bitnr & 0x1F;
472 replay_esn->bmp[nr] |= (1U << bitnr);
473 } else {
474 nr = (replay_esn->replay_window - 1) >> 5;
475 for (i = 0; i <= nr; i++)
476 replay_esn->bmp[i] = 0;
477
478 bitnr = (pos + diff) % replay_esn->replay_window;
479 nr = bitnr >> 5;
480 bitnr = bitnr & 0x1F;
481 replay_esn->bmp[nr] |= (1U << bitnr);
482 }
483
484 replay_esn->seq = seq;
485
486 if (unlikely(wrap > 0))
487 replay_esn->seq_hi++;
488 } else {
489 diff = replay_esn->seq - seq;
490
491 if (pos >= diff) {
492 bitnr = (pos - diff) % replay_esn->replay_window;
493 nr = bitnr >> 5;
494 bitnr = bitnr & 0x1F;
495 replay_esn->bmp[nr] |= (1U << bitnr);
496 } else {
497 bitnr = replay_esn->replay_window - (diff - pos);
498 nr = bitnr >> 5;
499 bitnr = bitnr & 0x1F;
500 replay_esn->bmp[nr] |= (1U << bitnr);
501 }
502 }
503
504 if (xfrm_aevent_is_on(xs_net(x)))
505 xfrm_replay_notify(x, XFRM_REPLAY_UPDATE);
506}
507
508static struct xfrm_replay xfrm_replay_legacy = {
509 .advance = xfrm_replay_advance,
510 .check = xfrm_replay_check,
511 .notify = xfrm_replay_notify,
512 .overflow = xfrm_replay_overflow,
513};
514
515static struct xfrm_replay xfrm_replay_bmp = {
516 .advance = xfrm_replay_advance_bmp,
517 .check = xfrm_replay_check_bmp,
518 .notify = xfrm_replay_notify_bmp,
519 .overflow = xfrm_replay_overflow_bmp,
520};
521
522static struct xfrm_replay xfrm_replay_esn = {
523 .advance = xfrm_replay_advance_esn,
524 .check = xfrm_replay_check_esn,
525 .notify = xfrm_replay_notify_bmp,
526 .overflow = xfrm_replay_overflow_esn,
527};
528
529int xfrm_init_replay(struct xfrm_state *x)
530{
531 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
532
533 if (replay_esn) {
534 if (replay_esn->replay_window >
535 replay_esn->bmp_len * sizeof(__u32) * 8)
536 return -EINVAL;
537
538 if ((x->props.flags & XFRM_STATE_ESN) && replay_esn->replay_window == 0)
539 return -EINVAL;
540
541 if ((x->props.flags & XFRM_STATE_ESN) && x->replay_esn)
542 x->repl = &xfrm_replay_esn;
543 else
544 x->repl = &xfrm_replay_bmp;
545 } else
546 x->repl = &xfrm_replay_legacy;
547
548 return 0;
549}
550EXPORT_SYMBOL(xfrm_init_replay);