blob: 39e02c54ed26544d2b0b669ee6444584b4b2c498 [file] [log] [blame]
Steffen Klassert9fdc4882011-03-08 00:08:32 +00001/*
2 * xfrm_replay.c - xfrm replay detection, derived from xfrm_state.c.
Steffen Klassert97e15c32011-03-08 00:09:09 +00003 *
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.
Steffen Klassert9fdc4882011-03-08 00:08:32 +000019 */
20
Paul Gortmakerbc3b2d72011-07-15 11:47:34 -040021#include <linux/export.h>
Steffen Klassert9fdc4882011-03-08 00:08:32 +000022#include <net/xfrm.h>
23
Steffen Klassert2cd08462011-03-08 00:09:51 +000024u32 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
Steffen Klassert9fdc4882011-03-08 00:08:32 +000049static 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
Steffen Klassert36ae0142011-03-28 19:45:52 +0000122 if (!x->props.replay_window)
123 return 0;
124
Steffen Klassert9fdc4882011-03-08 00:08:32 +0000125 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 xfrm_replay_notify(x, XFRM_REPLAY_UPDATE);
171}
172
Steffen Klassert97e15c32011-03-08 00:09:09 +0000173static 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;
Steffen Klassert36ae0142011-03-28 19:45:52 +0000200 u32 pos;
Steffen Klassert97e15c32011-03-08 00:09:09 +0000201 u32 seq = ntohl(net_seq);
202 u32 diff = replay_esn->seq - seq;
Steffen Klassert36ae0142011-03-28 19:45:52 +0000203
204 if (!replay_esn->replay_window)
205 return 0;
206
Steffen Klassert97e15c32011-03-08 00:09:09 +0000207 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
Steffen Klassert1d974372011-10-11 01:58:37 +0000218 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
219
220 if (pos >= diff)
Steffen Klassert97e15c32011-03-08 00:09:09 +0000221 bitnr = (pos - diff) % replay_esn->replay_window;
Steffen Klassert1d974372011-10-11 01:58:37 +0000222 else
Steffen Klassert97e15c32011-03-08 00:09:09 +0000223 bitnr = replay_esn->replay_window - (diff - pos);
Steffen Klassert1d974372011-10-11 01:58:37 +0000224
225 nr = bitnr >> 5;
226 bitnr = bitnr & 0x1F;
227 if (replay_esn->bmp[nr] & (1U << bitnr))
228 goto err_replay;
229
Steffen Klassert97e15c32011-03-08 00:09:09 +0000230 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 }
Steffen Klassert97e15c32011-03-08 00:09:09 +0000260 } else {
Steffen Klasserte7566822011-06-05 20:46:03 +0000261 nr = (replay_esn->replay_window - 1) >> 5;
Steffen Klassert97e15c32011-03-08 00:09:09 +0000262 for (i = 0; i <= nr; i++)
263 replay_esn->bmp[i] = 0;
Steffen Klassert97e15c32011-03-08 00:09:09 +0000264 }
265
Steffen Klassert1d974372011-10-11 01:58:37 +0000266 bitnr = (pos + diff) % replay_esn->replay_window;
Steffen Klassert97e15c32011-03-08 00:09:09 +0000267 replay_esn->seq = seq;
268 } else {
269 diff = replay_esn->seq - seq;
270
Steffen Klassert1d974372011-10-11 01:58:37 +0000271 if (pos >= diff)
Steffen Klassert97e15c32011-03-08 00:09:09 +0000272 bitnr = (pos - diff) % replay_esn->replay_window;
Steffen Klassert1d974372011-10-11 01:58:37 +0000273 else
Steffen Klassert97e15c32011-03-08 00:09:09 +0000274 bitnr = replay_esn->replay_window - (diff - pos);
Steffen Klassert97e15c32011-03-08 00:09:09 +0000275 }
276
Steffen Klassert1d974372011-10-11 01:58:37 +0000277 nr = bitnr >> 5;
278 bitnr = bitnr & 0x1F;
279 replay_esn->bmp[nr] |= (1U << bitnr);
280
Steffen Klassert97e15c32011-03-08 00:09:09 +0000281 if (xfrm_aevent_is_on(xs_net(x)))
282 xfrm_replay_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
Steffen Klassert2cd08462011-03-08 00:09:51 +0000335static 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;
Steffen Klassert36ae0142011-03-28 19:45:52 +0000370 u32 pos;
Steffen Klassert2cd08462011-03-08 00:09:51 +0000371 u32 seq = ntohl(net_seq);
Steffen Klassert2cd08462011-03-08 00:09:51 +0000372 u32 wsize = replay_esn->replay_window;
373 u32 top = replay_esn->seq;
374 u32 bottom = top - wsize + 1;
375
Steffen Klassert36ae0142011-03-28 19:45:52 +0000376 if (!wsize)
377 return 0;
378
Steffen Klassert2cd08462011-03-08 00:09:51 +0000379 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
Steffen Klassert1d974372011-10-11 01:58:37 +0000402 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
403
404 if (pos >= diff)
Steffen Klassert2cd08462011-03-08 00:09:51 +0000405 bitnr = (pos - diff) % replay_esn->replay_window;
Steffen Klassert1d974372011-10-11 01:58:37 +0000406 else
Steffen Klassert2cd08462011-03-08 00:09:51 +0000407 bitnr = replay_esn->replay_window - (diff - pos);
Steffen Klassert1d974372011-10-11 01:58:37 +0000408
409 nr = bitnr >> 5;
410 bitnr = bitnr & 0x1F;
411 if (replay_esn->bmp[nr] & (1U << bitnr))
412 goto err_replay;
413
Steffen Klassert2cd08462011-03-08 00:09:51 +0000414 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 }
Steffen Klassert2cd08462011-03-08 00:09:51 +0000451 } else {
Steffen Klasserte7566822011-06-05 20:46:03 +0000452 nr = (replay_esn->replay_window - 1) >> 5;
Steffen Klassert2cd08462011-03-08 00:09:51 +0000453 for (i = 0; i <= nr; i++)
454 replay_esn->bmp[i] = 0;
Steffen Klassert2cd08462011-03-08 00:09:51 +0000455 }
456
Steffen Klassert1d974372011-10-11 01:58:37 +0000457 bitnr = (pos + diff) % replay_esn->replay_window;
Steffen Klassert2cd08462011-03-08 00:09:51 +0000458 replay_esn->seq = seq;
459
460 if (unlikely(wrap > 0))
461 replay_esn->seq_hi++;
462 } else {
463 diff = replay_esn->seq - seq;
464
Steffen Klassert1d974372011-10-11 01:58:37 +0000465 if (pos >= diff)
Steffen Klassert2cd08462011-03-08 00:09:51 +0000466 bitnr = (pos - diff) % replay_esn->replay_window;
Steffen Klassert1d974372011-10-11 01:58:37 +0000467 else
Steffen Klassert2cd08462011-03-08 00:09:51 +0000468 bitnr = replay_esn->replay_window - (diff - pos);
Steffen Klassert2cd08462011-03-08 00:09:51 +0000469 }
470
Steffen Klassert1d974372011-10-11 01:58:37 +0000471 nr = bitnr >> 5;
472 bitnr = bitnr & 0x1F;
473 replay_esn->bmp[nr] |= (1U << bitnr);
474
Steffen Klassert2cd08462011-03-08 00:09:51 +0000475 if (xfrm_aevent_is_on(xs_net(x)))
476 xfrm_replay_notify(x, XFRM_REPLAY_UPDATE);
477}
478
Steffen Klassert9fdc4882011-03-08 00:08:32 +0000479static 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
Steffen Klassert97e15c32011-03-08 00:09:09 +0000486static 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
Steffen Klassert2cd08462011-03-08 00:09:51 +0000493static 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
Steffen Klassert9fdc4882011-03-08 00:08:32 +0000500int xfrm_init_replay(struct xfrm_state *x)
501{
Steffen Klassert97e15c32011-03-08 00:09:09 +0000502 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
503
504 if (replay_esn) {
505 if (replay_esn->replay_window >
Steffen Klassert3f602b02011-04-25 19:39:24 +0000506 replay_esn->bmp_len * sizeof(__u32) * 8)
Steffen Klassert97e15c32011-03-08 00:09:09 +0000507 return -EINVAL;
508
Steffen Klassert6fa5ddc2011-05-09 19:43:05 +0000509 if ((x->props.flags & XFRM_STATE_ESN) && replay_esn->replay_window == 0)
510 return -EINVAL;
511
Steffen Klassert2cd08462011-03-08 00:09:51 +0000512 if ((x->props.flags & XFRM_STATE_ESN) && x->replay_esn)
513 x->repl = &xfrm_replay_esn;
514 else
Steffen Klassert97e15c32011-03-08 00:09:09 +0000515 x->repl = &xfrm_replay_bmp;
516 } else
517 x->repl = &xfrm_replay_legacy;
518
Steffen Klassert9fdc4882011-03-08 00:08:32 +0000519 return 0;
520}
521EXPORT_SYMBOL(xfrm_init_replay);