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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_bmp(struct xfrm_state *x, int event);
39static void xfrm_replay_notify_esn(struct xfrm_state *x, int event);
40
41void xfrm_replay_notify(struct xfrm_state *x, int event)
42{
43 struct km_event c;
44 /* we send notify messages in case
45 * 1. we updated on of the sequence numbers, and the seqno difference
46 * is at least x->replay_maxdiff, in this case we also update the
47 * timeout of our timer function
48 * 2. if x->replay_maxage has elapsed since last update,
49 * and there were changes
50 *
51 * The state structure must be locked!
52 */
53
54 switch (x->repl_mode) {
55 case XFRM_REPLAY_MODE_LEGACY:
56 break;
57 case XFRM_REPLAY_MODE_BMP:
58 xfrm_replay_notify_bmp(x, event);
59 return;
60 case XFRM_REPLAY_MODE_ESN:
61 xfrm_replay_notify_esn(x, event);
62 return;
63 }
64
65 switch (event) {
66 case XFRM_REPLAY_UPDATE:
67 if (!x->replay_maxdiff ||
68 ((x->replay.seq - x->preplay.seq < x->replay_maxdiff) &&
69 (x->replay.oseq - x->preplay.oseq < x->replay_maxdiff))) {
70 if (x->xflags & XFRM_TIME_DEFER)
71 event = XFRM_REPLAY_TIMEOUT;
72 else
73 return;
74 }
75
76 break;
77
78 case XFRM_REPLAY_TIMEOUT:
79 if (memcmp(&x->replay, &x->preplay,
80 sizeof(struct xfrm_replay_state)) == 0) {
81 x->xflags |= XFRM_TIME_DEFER;
82 return;
83 }
84
85 break;
86 }
87
88 memcpy(&x->preplay, &x->replay, sizeof(struct xfrm_replay_state));
89 c.event = XFRM_MSG_NEWAE;
90 c.data.aevent = event;
91 km_state_notify(x, &c);
92
93 if (x->replay_maxage &&
94 !mod_timer(&x->rtimer, jiffies + x->replay_maxage))
95 x->xflags &= ~XFRM_TIME_DEFER;
96}
97
98static int __xfrm_replay_overflow(struct xfrm_state *x, struct sk_buff *skb)
99{
100 int err = 0;
101 struct net *net = xs_net(x);
102
103 if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
104 XFRM_SKB_CB(skb)->seq.output.low = ++x->replay.oseq;
105 XFRM_SKB_CB(skb)->seq.output.hi = 0;
106 if (unlikely(x->replay.oseq == 0) &&
107 !(x->props.extra_flags & XFRM_SA_XFLAG_OSEQ_MAY_WRAP)) {
108 x->replay.oseq--;
109 xfrm_audit_state_replay_overflow(x, skb);
110 err = -EOVERFLOW;
111
112 return err;
113 }
114 if (xfrm_aevent_is_on(net))
115 xfrm_replay_notify(x, XFRM_REPLAY_UPDATE);
116 }
117
118 return err;
119}
120
121static int xfrm_replay_check_legacy(struct xfrm_state *x,
122 struct sk_buff *skb, __be32 net_seq)
123{
124 u32 diff;
125 u32 seq = ntohl(net_seq);
126
127 if (!x->props.replay_window)
128 return 0;
129
130 if (unlikely(seq == 0))
131 goto err;
132
133 if (likely(seq > x->replay.seq))
134 return 0;
135
136 diff = x->replay.seq - seq;
137 if (diff >= x->props.replay_window) {
138 x->stats.replay_window++;
139 goto err;
140 }
141
142 if (x->replay.bitmap & (1U << diff)) {
143 x->stats.replay++;
144 goto err;
145 }
146 return 0;
147
148err:
149 xfrm_audit_state_replay(x, skb, net_seq);
150 return -EINVAL;
151}
152
153static void xfrm_replay_advance_bmp(struct xfrm_state *x, __be32 net_seq);
154static void xfrm_replay_advance_esn(struct xfrm_state *x, __be32 net_seq);
155
156void xfrm_replay_advance(struct xfrm_state *x, __be32 net_seq)
157{
158 u32 diff, seq;
159
160 switch (x->repl_mode) {
161 case XFRM_REPLAY_MODE_LEGACY:
162 break;
163 case XFRM_REPLAY_MODE_BMP:
164 return xfrm_replay_advance_bmp(x, net_seq);
165 case XFRM_REPLAY_MODE_ESN:
166 return xfrm_replay_advance_esn(x, net_seq);
167 }
168
169 if (!x->props.replay_window)
170 return;
171
172 seq = ntohl(net_seq);
173 if (seq > x->replay.seq) {
174 diff = seq - x->replay.seq;
175 if (diff < x->props.replay_window)
176 x->replay.bitmap = ((x->replay.bitmap) << diff) | 1;
177 else
178 x->replay.bitmap = 1;
179 x->replay.seq = seq;
180 } else {
181 diff = x->replay.seq - seq;
182 x->replay.bitmap |= (1U << diff);
183 }
184
185 if (xfrm_aevent_is_on(xs_net(x)))
186 xfrm_replay_notify(x, XFRM_REPLAY_UPDATE);
187}
188
189static int xfrm_replay_overflow_bmp(struct xfrm_state *x, struct sk_buff *skb)
190{
191 int err = 0;
192 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
193 struct net *net = xs_net(x);
194
195 if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
196 XFRM_SKB_CB(skb)->seq.output.low = ++replay_esn->oseq;
197 XFRM_SKB_CB(skb)->seq.output.hi = 0;
198 if (unlikely(replay_esn->oseq == 0) &&
199 !(x->props.extra_flags & XFRM_SA_XFLAG_OSEQ_MAY_WRAP)) {
200 replay_esn->oseq--;
201 xfrm_audit_state_replay_overflow(x, skb);
202 err = -EOVERFLOW;
203
204 return err;
205 }
206 if (xfrm_aevent_is_on(net))
207 xfrm_replay_notify(x, XFRM_REPLAY_UPDATE);
208 }
209
210 return err;
211}
212
213static int xfrm_replay_check_bmp(struct xfrm_state *x,
214 struct sk_buff *skb, __be32 net_seq)
215{
216 unsigned int bitnr, nr;
217 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
218 u32 pos;
219 u32 seq = ntohl(net_seq);
220 u32 diff = replay_esn->seq - seq;
221
222 if (!replay_esn->replay_window)
223 return 0;
224
225 if (unlikely(seq == 0))
226 goto err;
227
228 if (likely(seq > replay_esn->seq))
229 return 0;
230
231 if (diff >= replay_esn->replay_window) {
232 x->stats.replay_window++;
233 goto err;
234 }
235
236 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
237
238 if (pos >= diff)
239 bitnr = (pos - diff) % replay_esn->replay_window;
240 else
241 bitnr = replay_esn->replay_window - (diff - pos);
242
243 nr = bitnr >> 5;
244 bitnr = bitnr & 0x1F;
245 if (replay_esn->bmp[nr] & (1U << bitnr))
246 goto err_replay;
247
248 return 0;
249
250err_replay:
251 x->stats.replay++;
252err:
253 xfrm_audit_state_replay(x, skb, net_seq);
254 return -EINVAL;
255}
256
257static void xfrm_replay_advance_bmp(struct xfrm_state *x, __be32 net_seq)
258{
259 unsigned int bitnr, nr, i;
260 u32 diff;
261 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
262 u32 seq = ntohl(net_seq);
263 u32 pos;
264
265 if (!replay_esn->replay_window)
266 return;
267
268 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
269
270 if (seq > replay_esn->seq) {
271 diff = seq - replay_esn->seq;
272
273 if (diff < replay_esn->replay_window) {
274 for (i = 1; i < diff; i++) {
275 bitnr = (pos + i) % replay_esn->replay_window;
276 nr = bitnr >> 5;
277 bitnr = bitnr & 0x1F;
278 replay_esn->bmp[nr] &= ~(1U << bitnr);
279 }
280 } else {
281 nr = (replay_esn->replay_window - 1) >> 5;
282 for (i = 0; i <= nr; i++)
283 replay_esn->bmp[i] = 0;
284 }
285
286 bitnr = (pos + diff) % replay_esn->replay_window;
287 replay_esn->seq = seq;
288 } else {
289 diff = replay_esn->seq - seq;
290
291 if (pos >= diff)
292 bitnr = (pos - diff) % replay_esn->replay_window;
293 else
294 bitnr = replay_esn->replay_window - (diff - pos);
295 }
296
297 nr = bitnr >> 5;
298 bitnr = bitnr & 0x1F;
299 replay_esn->bmp[nr] |= (1U << bitnr);
300
301 if (xfrm_aevent_is_on(xs_net(x)))
302 xfrm_replay_notify(x, XFRM_REPLAY_UPDATE);
303}
304
305static void xfrm_replay_notify_bmp(struct xfrm_state *x, int event)
306{
307 struct km_event c;
308 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
309 struct xfrm_replay_state_esn *preplay_esn = x->preplay_esn;
310
311 /* we send notify messages in case
312 * 1. we updated on of the sequence numbers, and the seqno difference
313 * is at least x->replay_maxdiff, in this case we also update the
314 * timeout of our timer function
315 * 2. if x->replay_maxage has elapsed since last update,
316 * and there were changes
317 *
318 * The state structure must be locked!
319 */
320
321 switch (event) {
322 case XFRM_REPLAY_UPDATE:
323 if (!x->replay_maxdiff ||
324 ((replay_esn->seq - preplay_esn->seq < x->replay_maxdiff) &&
325 (replay_esn->oseq - preplay_esn->oseq
326 < x->replay_maxdiff))) {
327 if (x->xflags & XFRM_TIME_DEFER)
328 event = XFRM_REPLAY_TIMEOUT;
329 else
330 return;
331 }
332
333 break;
334
335 case XFRM_REPLAY_TIMEOUT:
336 if (memcmp(x->replay_esn, x->preplay_esn,
337 xfrm_replay_state_esn_len(replay_esn)) == 0) {
338 x->xflags |= XFRM_TIME_DEFER;
339 return;
340 }
341
342 break;
343 }
344
345 memcpy(x->preplay_esn, x->replay_esn,
346 xfrm_replay_state_esn_len(replay_esn));
347 c.event = XFRM_MSG_NEWAE;
348 c.data.aevent = event;
349 km_state_notify(x, &c);
350
351 if (x->replay_maxage &&
352 !mod_timer(&x->rtimer, jiffies + x->replay_maxage))
353 x->xflags &= ~XFRM_TIME_DEFER;
354}
355
356static void xfrm_replay_notify_esn(struct xfrm_state *x, int event)
357{
358 u32 seq_diff, oseq_diff;
359 struct km_event c;
360 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
361 struct xfrm_replay_state_esn *preplay_esn = x->preplay_esn;
362
363 /* we send notify messages in case
364 * 1. we updated on of the sequence numbers, and the seqno difference
365 * is at least x->replay_maxdiff, in this case we also update the
366 * timeout of our timer function
367 * 2. if x->replay_maxage has elapsed since last update,
368 * and there were changes
369 *
370 * The state structure must be locked!
371 */
372
373 switch (event) {
374 case XFRM_REPLAY_UPDATE:
375 if (x->replay_maxdiff) {
376 if (replay_esn->seq_hi == preplay_esn->seq_hi)
377 seq_diff = replay_esn->seq - preplay_esn->seq;
378 else
379 seq_diff = ~preplay_esn->seq + replay_esn->seq
380 + 1;
381
382 if (replay_esn->oseq_hi == preplay_esn->oseq_hi)
383 oseq_diff = replay_esn->oseq
384 - preplay_esn->oseq;
385 else
386 oseq_diff = ~preplay_esn->oseq
387 + replay_esn->oseq + 1;
388
389 if (seq_diff >= x->replay_maxdiff ||
390 oseq_diff >= x->replay_maxdiff)
391 break;
392 }
393
394 if (x->xflags & XFRM_TIME_DEFER)
395 event = XFRM_REPLAY_TIMEOUT;
396 else
397 return;
398
399 break;
400
401 case XFRM_REPLAY_TIMEOUT:
402 if (memcmp(x->replay_esn, x->preplay_esn,
403 xfrm_replay_state_esn_len(replay_esn)) == 0) {
404 x->xflags |= XFRM_TIME_DEFER;
405 return;
406 }
407
408 break;
409 }
410
411 memcpy(x->preplay_esn, x->replay_esn,
412 xfrm_replay_state_esn_len(replay_esn));
413 c.event = XFRM_MSG_NEWAE;
414 c.data.aevent = event;
415 km_state_notify(x, &c);
416
417 if (x->replay_maxage &&
418 !mod_timer(&x->rtimer, jiffies + x->replay_maxage))
419 x->xflags &= ~XFRM_TIME_DEFER;
420}
421
422static int xfrm_replay_overflow_esn(struct xfrm_state *x, struct sk_buff *skb)
423{
424 int err = 0;
425 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
426 struct net *net = xs_net(x);
427
428 if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
429 XFRM_SKB_CB(skb)->seq.output.low = ++replay_esn->oseq;
430 XFRM_SKB_CB(skb)->seq.output.hi = replay_esn->oseq_hi;
431
432 if (unlikely(replay_esn->oseq == 0)) {
433 XFRM_SKB_CB(skb)->seq.output.hi = ++replay_esn->oseq_hi;
434
435 if (replay_esn->oseq_hi == 0) {
436 replay_esn->oseq--;
437 replay_esn->oseq_hi--;
438 xfrm_audit_state_replay_overflow(x, skb);
439 err = -EOVERFLOW;
440
441 return err;
442 }
443 }
444 if (xfrm_aevent_is_on(net))
445 xfrm_replay_notify(x, XFRM_REPLAY_UPDATE);
446 }
447
448 return err;
449}
450
451static int xfrm_replay_check_esn(struct xfrm_state *x,
452 struct sk_buff *skb, __be32 net_seq)
453{
454 unsigned int bitnr, nr;
455 u32 diff;
456 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
457 u32 pos;
458 u32 seq = ntohl(net_seq);
459 u32 wsize = replay_esn->replay_window;
460 u32 top = replay_esn->seq;
461 u32 bottom = top - wsize + 1;
462
463 if (!wsize)
464 return 0;
465
466 if (unlikely(seq == 0 && replay_esn->seq_hi == 0 &&
467 (replay_esn->seq < replay_esn->replay_window - 1)))
468 goto err;
469
470 diff = top - seq;
471
472 if (likely(top >= wsize - 1)) {
473 /* A. same subspace */
474 if (likely(seq > top) || seq < bottom)
475 return 0;
476 } else {
477 /* B. window spans two subspaces */
478 if (likely(seq > top && seq < bottom))
479 return 0;
480 if (seq >= bottom)
481 diff = ~seq + top + 1;
482 }
483
484 if (diff >= replay_esn->replay_window) {
485 x->stats.replay_window++;
486 goto err;
487 }
488
489 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
490
491 if (pos >= diff)
492 bitnr = (pos - diff) % replay_esn->replay_window;
493 else
494 bitnr = replay_esn->replay_window - (diff - pos);
495
496 nr = bitnr >> 5;
497 bitnr = bitnr & 0x1F;
498 if (replay_esn->bmp[nr] & (1U << bitnr))
499 goto err_replay;
500
501 return 0;
502
503err_replay:
504 x->stats.replay++;
505err:
506 xfrm_audit_state_replay(x, skb, net_seq);
507 return -EINVAL;
508}
509
510int xfrm_replay_check(struct xfrm_state *x,
511 struct sk_buff *skb, __be32 net_seq)
512{
513 switch (x->repl_mode) {
514 case XFRM_REPLAY_MODE_LEGACY:
515 break;
516 case XFRM_REPLAY_MODE_BMP:
517 return xfrm_replay_check_bmp(x, skb, net_seq);
518 case XFRM_REPLAY_MODE_ESN:
519 return xfrm_replay_check_esn(x, skb, net_seq);
520 }
521
522 return xfrm_replay_check_legacy(x, skb, net_seq);
523}
524
525static int xfrm_replay_recheck_esn(struct xfrm_state *x,
526 struct sk_buff *skb, __be32 net_seq)
527{
528 if (unlikely(XFRM_SKB_CB(skb)->seq.input.hi !=
529 htonl(xfrm_replay_seqhi(x, net_seq)))) {
530 x->stats.replay_window++;
531 return -EINVAL;
532 }
533
534 return xfrm_replay_check_esn(x, skb, net_seq);
535}
536
537int xfrm_replay_recheck(struct xfrm_state *x,
538 struct sk_buff *skb, __be32 net_seq)
539{
540 switch (x->repl_mode) {
541 case XFRM_REPLAY_MODE_LEGACY:
542 break;
543 case XFRM_REPLAY_MODE_BMP:
544 /* no special recheck treatment */
545 return xfrm_replay_check_bmp(x, skb, net_seq);
546 case XFRM_REPLAY_MODE_ESN:
547 return xfrm_replay_recheck_esn(x, skb, net_seq);
548 }
549
550 return xfrm_replay_check_legacy(x, skb, net_seq);
551}
552
553static void xfrm_replay_advance_esn(struct xfrm_state *x, __be32 net_seq)
554{
555 unsigned int bitnr, nr, i;
556 int wrap;
557 u32 diff, pos, seq, seq_hi;
558 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
559
560 if (!replay_esn->replay_window)
561 return;
562
563 seq = ntohl(net_seq);
564 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
565 seq_hi = xfrm_replay_seqhi(x, net_seq);
566 wrap = seq_hi - replay_esn->seq_hi;
567
568 if ((!wrap && seq > replay_esn->seq) || wrap > 0) {
569 if (likely(!wrap))
570 diff = seq - replay_esn->seq;
571 else
572 diff = ~replay_esn->seq + seq + 1;
573
574 if (diff < replay_esn->replay_window) {
575 for (i = 1; i < diff; i++) {
576 bitnr = (pos + i) % replay_esn->replay_window;
577 nr = bitnr >> 5;
578 bitnr = bitnr & 0x1F;
579 replay_esn->bmp[nr] &= ~(1U << bitnr);
580 }
581 } else {
582 nr = (replay_esn->replay_window - 1) >> 5;
583 for (i = 0; i <= nr; i++)
584 replay_esn->bmp[i] = 0;
585 }
586
587 bitnr = (pos + diff) % replay_esn->replay_window;
588 replay_esn->seq = seq;
589
590 if (unlikely(wrap > 0))
591 replay_esn->seq_hi++;
592 } else {
593 diff = replay_esn->seq - seq;
594
595 if (pos >= diff)
596 bitnr = (pos - diff) % replay_esn->replay_window;
597 else
598 bitnr = replay_esn->replay_window - (diff - pos);
599 }
600
601 xfrm_dev_state_advance_esn(x);
602
603 nr = bitnr >> 5;
604 bitnr = bitnr & 0x1F;
605 replay_esn->bmp[nr] |= (1U << bitnr);
606
607 if (xfrm_aevent_is_on(xs_net(x)))
608 xfrm_replay_notify(x, XFRM_REPLAY_UPDATE);
609}
610
611#ifdef CONFIG_XFRM_OFFLOAD
612static int xfrm_replay_overflow_offload(struct xfrm_state *x, struct sk_buff *skb)
613{
614 int err = 0;
615 struct net *net = xs_net(x);
616 struct xfrm_offload *xo = xfrm_offload(skb);
617 __u32 oseq = x->replay.oseq;
618
619 if (!xo)
620 return __xfrm_replay_overflow(x, skb);
621
622 if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
623 if (!skb_is_gso(skb)) {
624 XFRM_SKB_CB(skb)->seq.output.low = ++oseq;
625 xo->seq.low = oseq;
626 } else {
627 XFRM_SKB_CB(skb)->seq.output.low = oseq + 1;
628 xo->seq.low = oseq + 1;
629 oseq += skb_shinfo(skb)->gso_segs;
630 }
631
632 XFRM_SKB_CB(skb)->seq.output.hi = 0;
633 xo->seq.hi = 0;
634 if (unlikely(oseq < x->replay.oseq) &&
635 !(x->props.extra_flags & XFRM_SA_XFLAG_OSEQ_MAY_WRAP)) {
636 xfrm_audit_state_replay_overflow(x, skb);
637 err = -EOVERFLOW;
638
639 return err;
640 }
641
642 x->replay.oseq = oseq;
643
644 if (xfrm_aevent_is_on(net))
645 xfrm_replay_notify(x, XFRM_REPLAY_UPDATE);
646 }
647
648 return err;
649}
650
651static int xfrm_replay_overflow_offload_bmp(struct xfrm_state *x, struct sk_buff *skb)
652{
653 int err = 0;
654 struct xfrm_offload *xo = xfrm_offload(skb);
655 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
656 struct net *net = xs_net(x);
657 __u32 oseq = replay_esn->oseq;
658
659 if (!xo)
660 return xfrm_replay_overflow_bmp(x, skb);
661
662 if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
663 if (!skb_is_gso(skb)) {
664 XFRM_SKB_CB(skb)->seq.output.low = ++oseq;
665 xo->seq.low = oseq;
666 } else {
667 XFRM_SKB_CB(skb)->seq.output.low = oseq + 1;
668 xo->seq.low = oseq + 1;
669 oseq += skb_shinfo(skb)->gso_segs;
670 }
671
672 XFRM_SKB_CB(skb)->seq.output.hi = 0;
673 xo->seq.hi = 0;
674 if (unlikely(oseq < replay_esn->oseq) &&
675 !(x->props.extra_flags & XFRM_SA_XFLAG_OSEQ_MAY_WRAP)) {
676 xfrm_audit_state_replay_overflow(x, skb);
677 err = -EOVERFLOW;
678
679 return err;
680 } else {
681 replay_esn->oseq = oseq;
682 }
683
684 if (xfrm_aevent_is_on(net))
685 xfrm_replay_notify(x, XFRM_REPLAY_UPDATE);
686 }
687
688 return err;
689}
690
691static int xfrm_replay_overflow_offload_esn(struct xfrm_state *x, struct sk_buff *skb)
692{
693 int err = 0;
694 struct xfrm_offload *xo = xfrm_offload(skb);
695 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
696 struct net *net = xs_net(x);
697 __u32 oseq = replay_esn->oseq;
698 __u32 oseq_hi = replay_esn->oseq_hi;
699
700 if (!xo)
701 return xfrm_replay_overflow_esn(x, skb);
702
703 if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
704 if (!skb_is_gso(skb)) {
705 XFRM_SKB_CB(skb)->seq.output.low = ++oseq;
706 XFRM_SKB_CB(skb)->seq.output.hi = oseq_hi;
707 xo->seq.low = oseq;
708 xo->seq.hi = oseq_hi;
709 } else {
710 XFRM_SKB_CB(skb)->seq.output.low = oseq + 1;
711 XFRM_SKB_CB(skb)->seq.output.hi = oseq_hi;
712 xo->seq.low = oseq + 1;
713 xo->seq.hi = oseq_hi;
714 oseq += skb_shinfo(skb)->gso_segs;
715 }
716
717 if (unlikely(xo->seq.low < replay_esn->oseq)) {
718 XFRM_SKB_CB(skb)->seq.output.hi = ++oseq_hi;
719 xo->seq.hi = oseq_hi;
720 replay_esn->oseq_hi = oseq_hi;
721 if (replay_esn->oseq_hi == 0) {
722 replay_esn->oseq--;
723 replay_esn->oseq_hi--;
724 xfrm_audit_state_replay_overflow(x, skb);
725 err = -EOVERFLOW;
726
727 return err;
728 }
729 }
730
731 replay_esn->oseq = oseq;
732
733 if (xfrm_aevent_is_on(net))
734 xfrm_replay_notify(x, XFRM_REPLAY_UPDATE);
735 }
736
737 return err;
738}
739
740int xfrm_replay_overflow(struct xfrm_state *x, struct sk_buff *skb)
741{
742 switch (x->repl_mode) {
743 case XFRM_REPLAY_MODE_LEGACY:
744 break;
745 case XFRM_REPLAY_MODE_BMP:
746 return xfrm_replay_overflow_offload_bmp(x, skb);
747 case XFRM_REPLAY_MODE_ESN:
748 return xfrm_replay_overflow_offload_esn(x, skb);
749 }
750
751 return xfrm_replay_overflow_offload(x, skb);
752}
753#else
754int xfrm_replay_overflow(struct xfrm_state *x, struct sk_buff *skb)
755{
756 switch (x->repl_mode) {
757 case XFRM_REPLAY_MODE_LEGACY:
758 break;
759 case XFRM_REPLAY_MODE_BMP:
760 return xfrm_replay_overflow_bmp(x, skb);
761 case XFRM_REPLAY_MODE_ESN:
762 return xfrm_replay_overflow_esn(x, skb);
763 }
764
765 return __xfrm_replay_overflow(x, skb);
766}
767#endif
768
769int xfrm_init_replay(struct xfrm_state *x, struct netlink_ext_ack *extack)
770{
771 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
772
773 if (replay_esn) {
774 if (replay_esn->replay_window >
775 replay_esn->bmp_len * sizeof(__u32) * 8) {
776 NL_SET_ERR_MSG(extack, "ESN replay window is too large for the chosen bitmap size");
777 return -EINVAL;
778 }
779
780 if (x->props.flags & XFRM_STATE_ESN) {
781 if (replay_esn->replay_window == 0) {
782 NL_SET_ERR_MSG(extack, "ESN replay window must be > 0");
783 return -EINVAL;
784 }
785 x->repl_mode = XFRM_REPLAY_MODE_ESN;
786 } else {
787 x->repl_mode = XFRM_REPLAY_MODE_BMP;
788 }
789 } else {
790 x->repl_mode = XFRM_REPLAY_MODE_LEGACY;
791 }
792
793 return 0;
794}
795EXPORT_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);