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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->props.extra_flags & XFRM_SA_XFLAG_OSEQ_MAY_WRAP)) {
94 x->replay.oseq--;
95 xfrm_audit_state_replay_overflow(x, skb);
96 err = -EOVERFLOW;
97
98 return err;
99 }
100 if (xfrm_aevent_is_on(net))
101 x->repl->notify(x, XFRM_REPLAY_UPDATE);
102 }
103
104 return err;
105}
106
107static int xfrm_replay_check(struct xfrm_state *x,
108 struct sk_buff *skb, __be32 net_seq)
109{
110 u32 diff;
111 u32 seq = ntohl(net_seq);
112
113 if (!x->props.replay_window)
114 return 0;
115
116 if (unlikely(seq == 0))
117 goto err;
118
119 if (likely(seq > x->replay.seq))
120 return 0;
121
122 diff = x->replay.seq - seq;
123 if (diff >= x->props.replay_window) {
124 x->stats.replay_window++;
125 goto err;
126 }
127
128 if (x->replay.bitmap & (1U << diff)) {
129 x->stats.replay++;
130 goto err;
131 }
132 return 0;
133
134err:
135 xfrm_audit_state_replay(x, skb, net_seq);
136 return -EINVAL;
137}
138
139static void xfrm_replay_advance(struct xfrm_state *x, __be32 net_seq)
140{
141 u32 diff;
142 u32 seq = ntohl(net_seq);
143
144 if (!x->props.replay_window)
145 return;
146
147 if (seq > x->replay.seq) {
148 diff = seq - x->replay.seq;
149 if (diff < x->props.replay_window)
150 x->replay.bitmap = ((x->replay.bitmap) << diff) | 1;
151 else
152 x->replay.bitmap = 1;
153 x->replay.seq = seq;
154 } else {
155 diff = x->replay.seq - seq;
156 x->replay.bitmap |= (1U << diff);
157 }
158
159 if (xfrm_aevent_is_on(xs_net(x)))
160 x->repl->notify(x, XFRM_REPLAY_UPDATE);
161}
162
163static int xfrm_replay_overflow_bmp(struct xfrm_state *x, struct sk_buff *skb)
164{
165 int err = 0;
166 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
167 struct net *net = xs_net(x);
168
169 if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
170 XFRM_SKB_CB(skb)->seq.output.low = ++replay_esn->oseq;
171 XFRM_SKB_CB(skb)->seq.output.hi = 0;
172 if (unlikely(replay_esn->oseq == 0) &&
173 !(x->props.extra_flags & XFRM_SA_XFLAG_OSEQ_MAY_WRAP)) {
174 replay_esn->oseq--;
175 xfrm_audit_state_replay_overflow(x, skb);
176 err = -EOVERFLOW;
177
178 return err;
179 }
180 if (xfrm_aevent_is_on(net))
181 x->repl->notify(x, XFRM_REPLAY_UPDATE);
182 }
183
184 return err;
185}
186
187static int xfrm_replay_check_bmp(struct xfrm_state *x,
188 struct sk_buff *skb, __be32 net_seq)
189{
190 unsigned int bitnr, nr;
191 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
192 u32 pos;
193 u32 seq = ntohl(net_seq);
194 u32 diff = replay_esn->seq - seq;
195
196 if (!replay_esn->replay_window)
197 return 0;
198
199 if (unlikely(seq == 0))
200 goto err;
201
202 if (likely(seq > replay_esn->seq))
203 return 0;
204
205 if (diff >= replay_esn->replay_window) {
206 x->stats.replay_window++;
207 goto err;
208 }
209
210 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
211
212 if (pos >= diff)
213 bitnr = (pos - diff) % replay_esn->replay_window;
214 else
215 bitnr = replay_esn->replay_window - (diff - pos);
216
217 nr = bitnr >> 5;
218 bitnr = bitnr & 0x1F;
219 if (replay_esn->bmp[nr] & (1U << bitnr))
220 goto err_replay;
221
222 return 0;
223
224err_replay:
225 x->stats.replay++;
226err:
227 xfrm_audit_state_replay(x, skb, net_seq);
228 return -EINVAL;
229}
230
231static void xfrm_replay_advance_bmp(struct xfrm_state *x, __be32 net_seq)
232{
233 unsigned int bitnr, nr, i;
234 u32 diff;
235 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
236 u32 seq = ntohl(net_seq);
237 u32 pos;
238
239 if (!replay_esn->replay_window)
240 return;
241
242 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
243
244 if (seq > replay_esn->seq) {
245 diff = seq - replay_esn->seq;
246
247 if (diff < replay_esn->replay_window) {
248 for (i = 1; i < diff; i++) {
249 bitnr = (pos + i) % replay_esn->replay_window;
250 nr = bitnr >> 5;
251 bitnr = bitnr & 0x1F;
252 replay_esn->bmp[nr] &= ~(1U << bitnr);
253 }
254 } else {
255 nr = (replay_esn->replay_window - 1) >> 5;
256 for (i = 0; i <= nr; i++)
257 replay_esn->bmp[i] = 0;
258 }
259
260 bitnr = (pos + diff) % replay_esn->replay_window;
261 replay_esn->seq = seq;
262 } else {
263 diff = replay_esn->seq - seq;
264
265 if (pos >= diff)
266 bitnr = (pos - diff) % replay_esn->replay_window;
267 else
268 bitnr = replay_esn->replay_window - (diff - pos);
269 }
270
271 nr = bitnr >> 5;
272 bitnr = bitnr & 0x1F;
273 replay_esn->bmp[nr] |= (1U << bitnr);
274
275 if (xfrm_aevent_is_on(xs_net(x)))
276 x->repl->notify(x, XFRM_REPLAY_UPDATE);
277}
278
279static void xfrm_replay_notify_bmp(struct xfrm_state *x, int event)
280{
281 struct km_event c;
282 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
283 struct xfrm_replay_state_esn *preplay_esn = x->preplay_esn;
284
285 /* we send notify messages in case
286 * 1. we updated on of the sequence numbers, and the seqno difference
287 * is at least x->replay_maxdiff, in this case we also update the
288 * timeout of our timer function
289 * 2. if x->replay_maxage has elapsed since last update,
290 * and there were changes
291 *
292 * The state structure must be locked!
293 */
294
295 switch (event) {
296 case XFRM_REPLAY_UPDATE:
297 if (!x->replay_maxdiff ||
298 ((replay_esn->seq - preplay_esn->seq < x->replay_maxdiff) &&
299 (replay_esn->oseq - preplay_esn->oseq
300 < x->replay_maxdiff))) {
301 if (x->xflags & XFRM_TIME_DEFER)
302 event = XFRM_REPLAY_TIMEOUT;
303 else
304 return;
305 }
306
307 break;
308
309 case XFRM_REPLAY_TIMEOUT:
310 if (memcmp(x->replay_esn, x->preplay_esn,
311 xfrm_replay_state_esn_len(replay_esn)) == 0) {
312 x->xflags |= XFRM_TIME_DEFER;
313 return;
314 }
315
316 break;
317 }
318
319 memcpy(x->preplay_esn, x->replay_esn,
320 xfrm_replay_state_esn_len(replay_esn));
321 c.event = XFRM_MSG_NEWAE;
322 c.data.aevent = event;
323 km_state_notify(x, &c);
324
325 if (x->replay_maxage &&
326 !mod_timer(&x->rtimer, jiffies + x->replay_maxage))
327 x->xflags &= ~XFRM_TIME_DEFER;
328}
329
330static void xfrm_replay_notify_esn(struct xfrm_state *x, int event)
331{
332 u32 seq_diff, oseq_diff;
333 struct km_event c;
334 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
335 struct xfrm_replay_state_esn *preplay_esn = x->preplay_esn;
336
337 /* we send notify messages in case
338 * 1. we updated on of the sequence numbers, and the seqno difference
339 * is at least x->replay_maxdiff, in this case we also update the
340 * timeout of our timer function
341 * 2. if x->replay_maxage has elapsed since last update,
342 * and there were changes
343 *
344 * The state structure must be locked!
345 */
346
347 switch (event) {
348 case XFRM_REPLAY_UPDATE:
349 if (x->replay_maxdiff) {
350 if (replay_esn->seq_hi == preplay_esn->seq_hi)
351 seq_diff = replay_esn->seq - preplay_esn->seq;
352 else
353 seq_diff = ~preplay_esn->seq + replay_esn->seq
354 + 1;
355
356 if (replay_esn->oseq_hi == preplay_esn->oseq_hi)
357 oseq_diff = replay_esn->oseq
358 - preplay_esn->oseq;
359 else
360 oseq_diff = ~preplay_esn->oseq
361 + replay_esn->oseq + 1;
362
363 if (seq_diff >= x->replay_maxdiff ||
364 oseq_diff >= x->replay_maxdiff)
365 break;
366 }
367
368 if (x->xflags & XFRM_TIME_DEFER)
369 event = XFRM_REPLAY_TIMEOUT;
370 else
371 return;
372
373 break;
374
375 case XFRM_REPLAY_TIMEOUT:
376 if (memcmp(x->replay_esn, x->preplay_esn,
377 xfrm_replay_state_esn_len(replay_esn)) == 0) {
378 x->xflags |= XFRM_TIME_DEFER;
379 return;
380 }
381
382 break;
383 }
384
385 memcpy(x->preplay_esn, x->replay_esn,
386 xfrm_replay_state_esn_len(replay_esn));
387 c.event = XFRM_MSG_NEWAE;
388 c.data.aevent = event;
389 km_state_notify(x, &c);
390
391 if (x->replay_maxage &&
392 !mod_timer(&x->rtimer, jiffies + x->replay_maxage))
393 x->xflags &= ~XFRM_TIME_DEFER;
394}
395
396static int xfrm_replay_overflow_esn(struct xfrm_state *x, struct sk_buff *skb)
397{
398 int err = 0;
399 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
400 struct net *net = xs_net(x);
401
402 if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
403 XFRM_SKB_CB(skb)->seq.output.low = ++replay_esn->oseq;
404 XFRM_SKB_CB(skb)->seq.output.hi = replay_esn->oseq_hi;
405
406 if (unlikely(replay_esn->oseq == 0)) {
407 XFRM_SKB_CB(skb)->seq.output.hi = ++replay_esn->oseq_hi;
408
409 if (replay_esn->oseq_hi == 0) {
410 replay_esn->oseq--;
411 replay_esn->oseq_hi--;
412 xfrm_audit_state_replay_overflow(x, skb);
413 err = -EOVERFLOW;
414
415 return err;
416 }
417 }
418 if (xfrm_aevent_is_on(net))
419 x->repl->notify(x, XFRM_REPLAY_UPDATE);
420 }
421
422 return err;
423}
424
425static int xfrm_replay_check_esn(struct xfrm_state *x,
426 struct sk_buff *skb, __be32 net_seq)
427{
428 unsigned int bitnr, nr;
429 u32 diff;
430 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
431 u32 pos;
432 u32 seq = ntohl(net_seq);
433 u32 wsize = replay_esn->replay_window;
434 u32 top = replay_esn->seq;
435 u32 bottom = top - wsize + 1;
436
437 if (!wsize)
438 return 0;
439
440 if (unlikely(seq == 0 && replay_esn->seq_hi == 0 &&
441 (replay_esn->seq < replay_esn->replay_window - 1)))
442 goto err;
443
444 diff = top - seq;
445
446 if (likely(top >= wsize - 1)) {
447 /* A. same subspace */
448 if (likely(seq > top) || seq < bottom)
449 return 0;
450 } else {
451 /* B. window spans two subspaces */
452 if (likely(seq > top && seq < bottom))
453 return 0;
454 if (seq >= bottom)
455 diff = ~seq + top + 1;
456 }
457
458 if (diff >= replay_esn->replay_window) {
459 x->stats.replay_window++;
460 goto err;
461 }
462
463 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
464
465 if (pos >= diff)
466 bitnr = (pos - diff) % replay_esn->replay_window;
467 else
468 bitnr = replay_esn->replay_window - (diff - pos);
469
470 nr = bitnr >> 5;
471 bitnr = bitnr & 0x1F;
472 if (replay_esn->bmp[nr] & (1U << bitnr))
473 goto err_replay;
474
475 return 0;
476
477err_replay:
478 x->stats.replay++;
479err:
480 xfrm_audit_state_replay(x, skb, net_seq);
481 return -EINVAL;
482}
483
484static int xfrm_replay_recheck_esn(struct xfrm_state *x,
485 struct sk_buff *skb, __be32 net_seq)
486{
487 if (unlikely(XFRM_SKB_CB(skb)->seq.input.hi !=
488 htonl(xfrm_replay_seqhi(x, net_seq)))) {
489 x->stats.replay_window++;
490 return -EINVAL;
491 }
492
493 return xfrm_replay_check_esn(x, skb, net_seq);
494}
495
496static void xfrm_replay_advance_esn(struct xfrm_state *x, __be32 net_seq)
497{
498 unsigned int bitnr, nr, i;
499 int wrap;
500 u32 diff, pos, seq, seq_hi;
501 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
502
503 if (!replay_esn->replay_window)
504 return;
505
506 seq = ntohl(net_seq);
507 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
508 seq_hi = xfrm_replay_seqhi(x, net_seq);
509 wrap = seq_hi - replay_esn->seq_hi;
510
511 if ((!wrap && seq > replay_esn->seq) || wrap > 0) {
512 if (likely(!wrap))
513 diff = seq - replay_esn->seq;
514 else
515 diff = ~replay_esn->seq + seq + 1;
516
517 if (diff < replay_esn->replay_window) {
518 for (i = 1; i < diff; i++) {
519 bitnr = (pos + i) % replay_esn->replay_window;
520 nr = bitnr >> 5;
521 bitnr = bitnr & 0x1F;
522 replay_esn->bmp[nr] &= ~(1U << bitnr);
523 }
524 } else {
525 nr = (replay_esn->replay_window - 1) >> 5;
526 for (i = 0; i <= nr; i++)
527 replay_esn->bmp[i] = 0;
528 }
529
530 bitnr = (pos + diff) % replay_esn->replay_window;
531 replay_esn->seq = seq;
532
533 if (unlikely(wrap > 0))
534 replay_esn->seq_hi++;
535 } else {
536 diff = replay_esn->seq - seq;
537
538 if (pos >= diff)
539 bitnr = (pos - diff) % replay_esn->replay_window;
540 else
541 bitnr = replay_esn->replay_window - (diff - pos);
542 }
543
544 xfrm_dev_state_advance_esn(x);
545
546 nr = bitnr >> 5;
547 bitnr = bitnr & 0x1F;
548 replay_esn->bmp[nr] |= (1U << bitnr);
549
550 if (xfrm_aevent_is_on(xs_net(x)))
551 x->repl->notify(x, XFRM_REPLAY_UPDATE);
552}
553
554#ifdef CONFIG_XFRM_OFFLOAD
555static int xfrm_replay_overflow_offload(struct xfrm_state *x, struct sk_buff *skb)
556{
557 int err = 0;
558 struct net *net = xs_net(x);
559 struct xfrm_offload *xo = xfrm_offload(skb);
560 __u32 oseq = x->replay.oseq;
561
562 if (!xo)
563 return xfrm_replay_overflow(x, skb);
564
565 if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
566 if (!skb_is_gso(skb)) {
567 XFRM_SKB_CB(skb)->seq.output.low = ++oseq;
568 xo->seq.low = oseq;
569 } else {
570 XFRM_SKB_CB(skb)->seq.output.low = oseq + 1;
571 xo->seq.low = oseq + 1;
572 oseq += skb_shinfo(skb)->gso_segs;
573 }
574
575 XFRM_SKB_CB(skb)->seq.output.hi = 0;
576 xo->seq.hi = 0;
577 if (unlikely(oseq < x->replay.oseq) &&
578 !(x->props.extra_flags & XFRM_SA_XFLAG_OSEQ_MAY_WRAP)) {
579 xfrm_audit_state_replay_overflow(x, skb);
580 err = -EOVERFLOW;
581
582 return err;
583 }
584
585 x->replay.oseq = oseq;
586
587 if (xfrm_aevent_is_on(net))
588 x->repl->notify(x, XFRM_REPLAY_UPDATE);
589 }
590
591 return err;
592}
593
594static int xfrm_replay_overflow_offload_bmp(struct xfrm_state *x, struct sk_buff *skb)
595{
596 int err = 0;
597 struct xfrm_offload *xo = xfrm_offload(skb);
598 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
599 struct net *net = xs_net(x);
600 __u32 oseq = replay_esn->oseq;
601
602 if (!xo)
603 return xfrm_replay_overflow_bmp(x, skb);
604
605 if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
606 if (!skb_is_gso(skb)) {
607 XFRM_SKB_CB(skb)->seq.output.low = ++oseq;
608 xo->seq.low = oseq;
609 } else {
610 XFRM_SKB_CB(skb)->seq.output.low = oseq + 1;
611 xo->seq.low = oseq + 1;
612 oseq += skb_shinfo(skb)->gso_segs;
613 }
614
615 XFRM_SKB_CB(skb)->seq.output.hi = 0;
616 xo->seq.hi = 0;
617 if (unlikely(oseq < replay_esn->oseq) &&
618 !(x->props.extra_flags & XFRM_SA_XFLAG_OSEQ_MAY_WRAP)) {
619 xfrm_audit_state_replay_overflow(x, skb);
620 err = -EOVERFLOW;
621
622 return err;
623 } else {
624 replay_esn->oseq = oseq;
625 }
626
627 if (xfrm_aevent_is_on(net))
628 x->repl->notify(x, XFRM_REPLAY_UPDATE);
629 }
630
631 return err;
632}
633
634static int xfrm_replay_overflow_offload_esn(struct xfrm_state *x, struct sk_buff *skb)
635{
636 int err = 0;
637 struct xfrm_offload *xo = xfrm_offload(skb);
638 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
639 struct net *net = xs_net(x);
640 __u32 oseq = replay_esn->oseq;
641 __u32 oseq_hi = replay_esn->oseq_hi;
642
643 if (!xo)
644 return xfrm_replay_overflow_esn(x, skb);
645
646 if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
647 if (!skb_is_gso(skb)) {
648 XFRM_SKB_CB(skb)->seq.output.low = ++oseq;
649 XFRM_SKB_CB(skb)->seq.output.hi = oseq_hi;
650 xo->seq.low = oseq;
651 xo->seq.hi = oseq_hi;
652 } else {
653 XFRM_SKB_CB(skb)->seq.output.low = oseq + 1;
654 XFRM_SKB_CB(skb)->seq.output.hi = oseq_hi;
655 xo->seq.low = oseq + 1;
656 xo->seq.hi = oseq_hi;
657 oseq += skb_shinfo(skb)->gso_segs;
658 }
659
660 if (unlikely(oseq < replay_esn->oseq)) {
661 XFRM_SKB_CB(skb)->seq.output.hi = ++oseq_hi;
662 xo->seq.hi = oseq_hi;
663 replay_esn->oseq_hi = oseq_hi;
664 if (replay_esn->oseq_hi == 0) {
665 replay_esn->oseq--;
666 replay_esn->oseq_hi--;
667 xfrm_audit_state_replay_overflow(x, skb);
668 err = -EOVERFLOW;
669
670 return err;
671 }
672 }
673
674 replay_esn->oseq = oseq;
675
676 if (xfrm_aevent_is_on(net))
677 x->repl->notify(x, XFRM_REPLAY_UPDATE);
678 }
679
680 return err;
681}
682
683static const struct xfrm_replay xfrm_replay_legacy = {
684 .advance = xfrm_replay_advance,
685 .check = xfrm_replay_check,
686 .recheck = xfrm_replay_check,
687 .notify = xfrm_replay_notify,
688 .overflow = xfrm_replay_overflow_offload,
689};
690
691static const struct xfrm_replay xfrm_replay_bmp = {
692 .advance = xfrm_replay_advance_bmp,
693 .check = xfrm_replay_check_bmp,
694 .recheck = xfrm_replay_check_bmp,
695 .notify = xfrm_replay_notify_bmp,
696 .overflow = xfrm_replay_overflow_offload_bmp,
697};
698
699static const struct xfrm_replay xfrm_replay_esn = {
700 .advance = xfrm_replay_advance_esn,
701 .check = xfrm_replay_check_esn,
702 .recheck = xfrm_replay_recheck_esn,
703 .notify = xfrm_replay_notify_esn,
704 .overflow = xfrm_replay_overflow_offload_esn,
705};
706#else
707static const struct xfrm_replay xfrm_replay_legacy = {
708 .advance = xfrm_replay_advance,
709 .check = xfrm_replay_check,
710 .recheck = xfrm_replay_check,
711 .notify = xfrm_replay_notify,
712 .overflow = xfrm_replay_overflow,
713};
714
715static const struct xfrm_replay xfrm_replay_bmp = {
716 .advance = xfrm_replay_advance_bmp,
717 .check = xfrm_replay_check_bmp,
718 .recheck = xfrm_replay_check_bmp,
719 .notify = xfrm_replay_notify_bmp,
720 .overflow = xfrm_replay_overflow_bmp,
721};
722
723static const struct xfrm_replay xfrm_replay_esn = {
724 .advance = xfrm_replay_advance_esn,
725 .check = xfrm_replay_check_esn,
726 .recheck = xfrm_replay_recheck_esn,
727 .notify = xfrm_replay_notify_esn,
728 .overflow = xfrm_replay_overflow_esn,
729};
730#endif
731
732int xfrm_init_replay(struct xfrm_state *x)
733{
734 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
735
736 if (replay_esn) {
737 if (replay_esn->replay_window >
738 replay_esn->bmp_len * sizeof(__u32) * 8)
739 return -EINVAL;
740
741 if (x->props.flags & XFRM_STATE_ESN) {
742 if (replay_esn->replay_window == 0)
743 return -EINVAL;
744 x->repl = &xfrm_replay_esn;
745 } else {
746 x->repl = &xfrm_replay_bmp;
747 }
748 } else {
749 x->repl = &xfrm_replay_legacy;
750 }
751
752 return 0;
753}
754EXPORT_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 if (unlikely(x->replay.oseq == 0)) {
103 x->replay.oseq--;
104 xfrm_audit_state_replay_overflow(x, skb);
105 err = -EOVERFLOW;
106
107 return err;
108 }
109 if (xfrm_aevent_is_on(net))
110 x->repl->notify(x, XFRM_REPLAY_UPDATE);
111 }
112
113 return err;
114}
115
116static int xfrm_replay_check(struct xfrm_state *x,
117 struct sk_buff *skb, __be32 net_seq)
118{
119 u32 diff;
120 u32 seq = ntohl(net_seq);
121
122 if (!x->props.replay_window)
123 return 0;
124
125 if (unlikely(seq == 0))
126 goto err;
127
128 if (likely(seq > x->replay.seq))
129 return 0;
130
131 diff = x->replay.seq - seq;
132 if (diff >= min_t(unsigned int, x->props.replay_window,
133 sizeof(x->replay.bitmap) * 8)) {
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 if (unlikely(replay_esn->oseq == 0)) {
182 replay_esn->oseq--;
183 xfrm_audit_state_replay_overflow(x, skb);
184 err = -EOVERFLOW;
185
186 return err;
187 }
188 if (xfrm_aevent_is_on(net))
189 x->repl->notify(x, XFRM_REPLAY_UPDATE);
190 }
191
192 return err;
193}
194
195static int xfrm_replay_check_bmp(struct xfrm_state *x,
196 struct sk_buff *skb, __be32 net_seq)
197{
198 unsigned int bitnr, nr;
199 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
200 u32 pos;
201 u32 seq = ntohl(net_seq);
202 u32 diff = replay_esn->seq - seq;
203
204 if (!replay_esn->replay_window)
205 return 0;
206
207 if (unlikely(seq == 0))
208 goto err;
209
210 if (likely(seq > replay_esn->seq))
211 return 0;
212
213 if (diff >= replay_esn->replay_window) {
214 x->stats.replay_window++;
215 goto err;
216 }
217
218 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
219
220 if (pos >= diff)
221 bitnr = (pos - diff) % replay_esn->replay_window;
222 else
223 bitnr = replay_esn->replay_window - (diff - pos);
224
225 nr = bitnr >> 5;
226 bitnr = bitnr & 0x1F;
227 if (replay_esn->bmp[nr] & (1U << bitnr))
228 goto err_replay;
229
230 return 0;
231
232err_replay:
233 x->stats.replay++;
234err:
235 xfrm_audit_state_replay(x, skb, net_seq);
236 return -EINVAL;
237}
238
239static void xfrm_replay_advance_bmp(struct xfrm_state *x, __be32 net_seq)
240{
241 unsigned int bitnr, nr, i;
242 u32 diff;
243 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
244 u32 seq = ntohl(net_seq);
245 u32 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
246
247 if (!replay_esn->replay_window)
248 return;
249
250 if (seq > replay_esn->seq) {
251 diff = seq - replay_esn->seq;
252
253 if (diff < replay_esn->replay_window) {
254 for (i = 1; i < diff; i++) {
255 bitnr = (pos + i) % replay_esn->replay_window;
256 nr = bitnr >> 5;
257 bitnr = bitnr & 0x1F;
258 replay_esn->bmp[nr] &= ~(1U << bitnr);
259 }
260 } else {
261 nr = (replay_esn->replay_window - 1) >> 5;
262 for (i = 0; i <= nr; i++)
263 replay_esn->bmp[i] = 0;
264 }
265
266 bitnr = (pos + diff) % replay_esn->replay_window;
267 replay_esn->seq = seq;
268 } else {
269 diff = replay_esn->seq - seq;
270
271 if (pos >= diff)
272 bitnr = (pos - diff) % replay_esn->replay_window;
273 else
274 bitnr = replay_esn->replay_window - (diff - pos);
275 }
276
277 nr = bitnr >> 5;
278 bitnr = bitnr & 0x1F;
279 replay_esn->bmp[nr] |= (1U << bitnr);
280
281 if (xfrm_aevent_is_on(xs_net(x)))
282 x->repl->notify(x, XFRM_REPLAY_UPDATE);
283}
284
285static void xfrm_replay_notify_bmp(struct xfrm_state *x, int event)
286{
287 struct km_event c;
288 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
289 struct xfrm_replay_state_esn *preplay_esn = x->preplay_esn;
290
291 /* we send notify messages in case
292 * 1. we updated on of the sequence numbers, and the seqno difference
293 * is at least x->replay_maxdiff, in this case we also update the
294 * timeout of our timer function
295 * 2. if x->replay_maxage has elapsed since last update,
296 * and there were changes
297 *
298 * The state structure must be locked!
299 */
300
301 switch (event) {
302 case XFRM_REPLAY_UPDATE:
303 if (x->replay_maxdiff &&
304 (replay_esn->seq - preplay_esn->seq < x->replay_maxdiff) &&
305 (replay_esn->oseq - preplay_esn->oseq < x->replay_maxdiff)) {
306 if (x->xflags & XFRM_TIME_DEFER)
307 event = XFRM_REPLAY_TIMEOUT;
308 else
309 return;
310 }
311
312 break;
313
314 case XFRM_REPLAY_TIMEOUT:
315 if (memcmp(x->replay_esn, x->preplay_esn,
316 xfrm_replay_state_esn_len(replay_esn)) == 0) {
317 x->xflags |= XFRM_TIME_DEFER;
318 return;
319 }
320
321 break;
322 }
323
324 memcpy(x->preplay_esn, x->replay_esn,
325 xfrm_replay_state_esn_len(replay_esn));
326 c.event = XFRM_MSG_NEWAE;
327 c.data.aevent = event;
328 km_state_notify(x, &c);
329
330 if (x->replay_maxage &&
331 !mod_timer(&x->rtimer, jiffies + x->replay_maxage))
332 x->xflags &= ~XFRM_TIME_DEFER;
333}
334
335static int xfrm_replay_overflow_esn(struct xfrm_state *x, struct sk_buff *skb)
336{
337 int err = 0;
338 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
339 struct net *net = xs_net(x);
340
341 if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
342 XFRM_SKB_CB(skb)->seq.output.low = ++replay_esn->oseq;
343 XFRM_SKB_CB(skb)->seq.output.hi = replay_esn->oseq_hi;
344
345 if (unlikely(replay_esn->oseq == 0)) {
346 XFRM_SKB_CB(skb)->seq.output.hi = ++replay_esn->oseq_hi;
347
348 if (replay_esn->oseq_hi == 0) {
349 replay_esn->oseq--;
350 replay_esn->oseq_hi--;
351 xfrm_audit_state_replay_overflow(x, skb);
352 err = -EOVERFLOW;
353
354 return err;
355 }
356 }
357 if (xfrm_aevent_is_on(net))
358 x->repl->notify(x, XFRM_REPLAY_UPDATE);
359 }
360
361 return err;
362}
363
364static int xfrm_replay_check_esn(struct xfrm_state *x,
365 struct sk_buff *skb, __be32 net_seq)
366{
367 unsigned int bitnr, nr;
368 u32 diff;
369 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
370 u32 pos;
371 u32 seq = ntohl(net_seq);
372 u32 wsize = replay_esn->replay_window;
373 u32 top = replay_esn->seq;
374 u32 bottom = top - wsize + 1;
375
376 if (!wsize)
377 return 0;
378
379 if (unlikely(seq == 0 && replay_esn->seq_hi == 0 &&
380 (replay_esn->seq < replay_esn->replay_window - 1)))
381 goto err;
382
383 diff = top - seq;
384
385 if (likely(top >= wsize - 1)) {
386 /* A. same subspace */
387 if (likely(seq > top) || seq < bottom)
388 return 0;
389 } else {
390 /* B. window spans two subspaces */
391 if (likely(seq > top && seq < bottom))
392 return 0;
393 if (seq >= bottom)
394 diff = ~seq + top + 1;
395 }
396
397 if (diff >= replay_esn->replay_window) {
398 x->stats.replay_window++;
399 goto err;
400 }
401
402 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
403
404 if (pos >= diff)
405 bitnr = (pos - diff) % replay_esn->replay_window;
406 else
407 bitnr = replay_esn->replay_window - (diff - pos);
408
409 nr = bitnr >> 5;
410 bitnr = bitnr & 0x1F;
411 if (replay_esn->bmp[nr] & (1U << bitnr))
412 goto err_replay;
413
414 return 0;
415
416err_replay:
417 x->stats.replay++;
418err:
419 xfrm_audit_state_replay(x, skb, net_seq);
420 return -EINVAL;
421}
422
423static void xfrm_replay_advance_esn(struct xfrm_state *x, __be32 net_seq)
424{
425 unsigned int bitnr, nr, i;
426 int wrap;
427 u32 diff, pos, seq, seq_hi;
428 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
429
430 if (!replay_esn->replay_window)
431 return;
432
433 seq = ntohl(net_seq);
434 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
435 seq_hi = xfrm_replay_seqhi(x, net_seq);
436 wrap = seq_hi - replay_esn->seq_hi;
437
438 if ((!wrap && seq > replay_esn->seq) || wrap > 0) {
439 if (likely(!wrap))
440 diff = seq - replay_esn->seq;
441 else
442 diff = ~replay_esn->seq + seq + 1;
443
444 if (diff < replay_esn->replay_window) {
445 for (i = 1; i < diff; i++) {
446 bitnr = (pos + i) % replay_esn->replay_window;
447 nr = bitnr >> 5;
448 bitnr = bitnr & 0x1F;
449 replay_esn->bmp[nr] &= ~(1U << bitnr);
450 }
451 } else {
452 nr = (replay_esn->replay_window - 1) >> 5;
453 for (i = 0; i <= nr; i++)
454 replay_esn->bmp[i] = 0;
455 }
456
457 bitnr = (pos + diff) % replay_esn->replay_window;
458 replay_esn->seq = seq;
459
460 if (unlikely(wrap > 0))
461 replay_esn->seq_hi++;
462 } else {
463 diff = replay_esn->seq - seq;
464
465 if (pos >= diff)
466 bitnr = (pos - diff) % replay_esn->replay_window;
467 else
468 bitnr = replay_esn->replay_window - (diff - pos);
469 }
470
471 nr = bitnr >> 5;
472 bitnr = bitnr & 0x1F;
473 replay_esn->bmp[nr] |= (1U << bitnr);
474
475 if (xfrm_aevent_is_on(xs_net(x)))
476 x->repl->notify(x, XFRM_REPLAY_UPDATE);
477}
478
479static struct xfrm_replay xfrm_replay_legacy = {
480 .advance = xfrm_replay_advance,
481 .check = xfrm_replay_check,
482 .notify = xfrm_replay_notify,
483 .overflow = xfrm_replay_overflow,
484};
485
486static struct xfrm_replay xfrm_replay_bmp = {
487 .advance = xfrm_replay_advance_bmp,
488 .check = xfrm_replay_check_bmp,
489 .notify = xfrm_replay_notify_bmp,
490 .overflow = xfrm_replay_overflow_bmp,
491};
492
493static struct xfrm_replay xfrm_replay_esn = {
494 .advance = xfrm_replay_advance_esn,
495 .check = xfrm_replay_check_esn,
496 .notify = xfrm_replay_notify_bmp,
497 .overflow = xfrm_replay_overflow_esn,
498};
499
500int xfrm_init_replay(struct xfrm_state *x)
501{
502 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
503
504 if (replay_esn) {
505 if (replay_esn->replay_window >
506 replay_esn->bmp_len * sizeof(__u32) * 8)
507 return -EINVAL;
508
509 if ((x->props.flags & XFRM_STATE_ESN) && replay_esn->replay_window == 0)
510 return -EINVAL;
511
512 if ((x->props.flags & XFRM_STATE_ESN) && x->replay_esn)
513 x->repl = &xfrm_replay_esn;
514 else
515 x->repl = &xfrm_replay_bmp;
516 } else
517 x->repl = &xfrm_replay_legacy;
518
519 return 0;
520}
521EXPORT_SYMBOL(xfrm_init_replay);