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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 <linux/export.h>
22#include <net/xfrm.h>
23
24u32 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
49static 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
95static 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
117static 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
144err:
145 xfrm_audit_state_replay(x, skb, net_seq);
146 return -EINVAL;
147}
148
149static 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
173static 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
196static 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
233err_replay:
234 x->stats.replay++;
235err:
236 xfrm_audit_state_replay(x, skb, net_seq);
237 return -EINVAL;
238}
239
240static 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
288static 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
339static 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
405static 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
434static 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
486err_replay:
487 x->stats.replay++;
488err:
489 xfrm_audit_state_replay(x, skb, net_seq);
490 return -EINVAL;
491}
492
493static 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
505static 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
561static const 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
569static const 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
577static const 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
585int 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}
605EXPORT_SYMBOL(xfrm_init_replay);