2 * xfrm_replay.c - xfrm replay detection, derived from xfrm_state.c.
4 * Copyright (C) 2010 secunet Security Networks AG
5 * Copyright (C) 2010 Steffen Klassert <steffen.klassert@secunet.com>
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.
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
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.
23 u32 xfrm_replay_seqhi(struct xfrm_state *x, __be32 net_seq)
25 u32 seq, seq_hi, bottom;
26 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
28 if (!(x->props.flags & XFRM_STATE_ESN))
32 seq_hi = replay_esn->seq_hi;
33 bottom = replay_esn->seq - replay_esn->replay_window + 1;
35 if (likely(replay_esn->seq >= replay_esn->replay_window - 1)) {
36 /* A. same subspace */
37 if (unlikely(seq < bottom))
40 /* B. window spans two subspaces */
41 if (unlikely(seq >= bottom))
48 static void xfrm_replay_notify(struct xfrm_state *x, int event)
51 /* we send notify messages in case
52 * 1. we updated on of the sequence numbers, and the seqno difference
53 * is at least x->replay_maxdiff, in this case we also update the
54 * timeout of our timer function
55 * 2. if x->replay_maxage has elapsed since last update,
56 * and there were changes
58 * The state structure must be locked!
62 case XFRM_REPLAY_UPDATE:
63 if (x->replay_maxdiff &&
64 (x->replay.seq - x->preplay.seq < x->replay_maxdiff) &&
65 (x->replay.oseq - x->preplay.oseq < x->replay_maxdiff)) {
66 if (x->xflags & XFRM_TIME_DEFER)
67 event = XFRM_REPLAY_TIMEOUT;
74 case XFRM_REPLAY_TIMEOUT:
75 if (memcmp(&x->replay, &x->preplay,
76 sizeof(struct xfrm_replay_state)) == 0) {
77 x->xflags |= XFRM_TIME_DEFER;
84 memcpy(&x->preplay, &x->replay, sizeof(struct xfrm_replay_state));
85 c.event = XFRM_MSG_NEWAE;
86 c.data.aevent = event;
87 km_state_notify(x, &c);
89 if (x->replay_maxage &&
90 !mod_timer(&x->rtimer, jiffies + x->replay_maxage))
91 x->xflags &= ~XFRM_TIME_DEFER;
94 static int xfrm_replay_overflow(struct xfrm_state *x, struct sk_buff *skb)
97 struct net *net = xs_net(x);
99 if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
100 XFRM_SKB_CB(skb)->seq.output.low = ++x->replay.oseq;
101 if (unlikely(x->replay.oseq == 0)) {
103 xfrm_audit_state_replay_overflow(x, skb);
108 if (xfrm_aevent_is_on(net))
109 x->repl->notify(x, XFRM_REPLAY_UPDATE);
115 static int xfrm_replay_check(struct xfrm_state *x,
116 struct sk_buff *skb, __be32 net_seq)
119 u32 seq = ntohl(net_seq);
121 if (!x->props.replay_window)
124 if (unlikely(seq == 0))
127 if (likely(seq > x->replay.seq))
130 diff = x->replay.seq - seq;
131 if (diff >= min_t(unsigned int, x->props.replay_window,
132 sizeof(x->replay.bitmap) * 8)) {
133 x->stats.replay_window++;
137 if (x->replay.bitmap & (1U << diff)) {
144 xfrm_audit_state_replay(x, skb, net_seq);
148 static void xfrm_replay_advance(struct xfrm_state *x, __be32 net_seq)
151 u32 seq = ntohl(net_seq);
153 if (!x->props.replay_window)
156 if (seq > x->replay.seq) {
157 diff = seq - x->replay.seq;
158 if (diff < x->props.replay_window)
159 x->replay.bitmap = ((x->replay.bitmap) << diff) | 1;
161 x->replay.bitmap = 1;
164 diff = x->replay.seq - seq;
165 x->replay.bitmap |= (1U << diff);
168 if (xfrm_aevent_is_on(xs_net(x)))
169 xfrm_replay_notify(x, XFRM_REPLAY_UPDATE);
172 static int xfrm_replay_overflow_bmp(struct xfrm_state *x, struct sk_buff *skb)
175 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
176 struct net *net = xs_net(x);
178 if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
179 XFRM_SKB_CB(skb)->seq.output.low = ++replay_esn->oseq;
180 if (unlikely(replay_esn->oseq == 0)) {
182 xfrm_audit_state_replay_overflow(x, skb);
187 if (xfrm_aevent_is_on(net))
188 x->repl->notify(x, XFRM_REPLAY_UPDATE);
194 static int xfrm_replay_check_bmp(struct xfrm_state *x,
195 struct sk_buff *skb, __be32 net_seq)
197 unsigned int bitnr, nr;
198 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
200 u32 seq = ntohl(net_seq);
201 u32 diff = replay_esn->seq - seq;
203 if (!replay_esn->replay_window)
206 if (unlikely(seq == 0))
209 if (likely(seq > replay_esn->seq))
212 if (diff >= replay_esn->replay_window) {
213 x->stats.replay_window++;
217 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
220 bitnr = (pos - diff) % replay_esn->replay_window;
222 bitnr = replay_esn->replay_window - (diff - pos);
225 bitnr = bitnr & 0x1F;
226 if (replay_esn->bmp[nr] & (1U << bitnr))
234 xfrm_audit_state_replay(x, skb, net_seq);
238 static void xfrm_replay_advance_bmp(struct xfrm_state *x, __be32 net_seq)
240 unsigned int bitnr, nr, i;
242 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
243 u32 seq = ntohl(net_seq);
244 u32 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
246 if (!replay_esn->replay_window)
249 if (seq > replay_esn->seq) {
250 diff = seq - replay_esn->seq;
252 if (diff < replay_esn->replay_window) {
253 for (i = 1; i < diff; i++) {
254 bitnr = (pos + i) % replay_esn->replay_window;
256 bitnr = bitnr & 0x1F;
257 replay_esn->bmp[nr] &= ~(1U << bitnr);
260 nr = (replay_esn->replay_window - 1) >> 5;
261 for (i = 0; i <= nr; i++)
262 replay_esn->bmp[i] = 0;
265 bitnr = (pos + diff) % replay_esn->replay_window;
266 replay_esn->seq = seq;
268 diff = replay_esn->seq - seq;
271 bitnr = (pos - diff) % replay_esn->replay_window;
273 bitnr = replay_esn->replay_window - (diff - pos);
277 bitnr = bitnr & 0x1F;
278 replay_esn->bmp[nr] |= (1U << bitnr);
280 if (xfrm_aevent_is_on(xs_net(x)))
281 xfrm_replay_notify(x, XFRM_REPLAY_UPDATE);
284 static void xfrm_replay_notify_bmp(struct xfrm_state *x, int event)
287 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
288 struct xfrm_replay_state_esn *preplay_esn = x->preplay_esn;
290 /* we send notify messages in case
291 * 1. we updated on of the sequence numbers, and the seqno difference
292 * is at least x->replay_maxdiff, in this case we also update the
293 * timeout of our timer function
294 * 2. if x->replay_maxage has elapsed since last update,
295 * and there were changes
297 * The state structure must be locked!
301 case XFRM_REPLAY_UPDATE:
302 if (x->replay_maxdiff &&
303 (replay_esn->seq - preplay_esn->seq < x->replay_maxdiff) &&
304 (replay_esn->oseq - preplay_esn->oseq < x->replay_maxdiff)) {
305 if (x->xflags & XFRM_TIME_DEFER)
306 event = XFRM_REPLAY_TIMEOUT;
313 case XFRM_REPLAY_TIMEOUT:
314 if (memcmp(x->replay_esn, x->preplay_esn,
315 xfrm_replay_state_esn_len(replay_esn)) == 0) {
316 x->xflags |= XFRM_TIME_DEFER;
323 memcpy(x->preplay_esn, x->replay_esn,
324 xfrm_replay_state_esn_len(replay_esn));
325 c.event = XFRM_MSG_NEWAE;
326 c.data.aevent = event;
327 km_state_notify(x, &c);
329 if (x->replay_maxage &&
330 !mod_timer(&x->rtimer, jiffies + x->replay_maxage))
331 x->xflags &= ~XFRM_TIME_DEFER;
334 static int xfrm_replay_overflow_esn(struct xfrm_state *x, struct sk_buff *skb)
337 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
338 struct net *net = xs_net(x);
340 if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
341 XFRM_SKB_CB(skb)->seq.output.low = ++replay_esn->oseq;
342 XFRM_SKB_CB(skb)->seq.output.hi = replay_esn->oseq_hi;
344 if (unlikely(replay_esn->oseq == 0)) {
345 XFRM_SKB_CB(skb)->seq.output.hi = ++replay_esn->oseq_hi;
347 if (replay_esn->oseq_hi == 0) {
349 replay_esn->oseq_hi--;
350 xfrm_audit_state_replay_overflow(x, skb);
356 if (xfrm_aevent_is_on(net))
357 x->repl->notify(x, XFRM_REPLAY_UPDATE);
363 static int xfrm_replay_check_esn(struct xfrm_state *x,
364 struct sk_buff *skb, __be32 net_seq)
366 unsigned int bitnr, nr;
368 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
370 u32 seq = ntohl(net_seq);
371 u32 wsize = replay_esn->replay_window;
372 u32 top = replay_esn->seq;
373 u32 bottom = top - wsize + 1;
378 if (unlikely(seq == 0 && replay_esn->seq_hi == 0 &&
379 (replay_esn->seq < replay_esn->replay_window - 1)))
384 if (likely(top >= wsize - 1)) {
385 /* A. same subspace */
386 if (likely(seq > top) || seq < bottom)
389 /* B. window spans two subspaces */
390 if (likely(seq > top && seq < bottom))
393 diff = ~seq + top + 1;
396 if (diff >= replay_esn->replay_window) {
397 x->stats.replay_window++;
401 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
404 bitnr = (pos - diff) % replay_esn->replay_window;
406 bitnr = replay_esn->replay_window - (diff - pos);
409 bitnr = bitnr & 0x1F;
410 if (replay_esn->bmp[nr] & (1U << bitnr))
418 xfrm_audit_state_replay(x, skb, net_seq);
422 static void xfrm_replay_advance_esn(struct xfrm_state *x, __be32 net_seq)
424 unsigned int bitnr, nr, i;
426 u32 diff, pos, seq, seq_hi;
427 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
429 if (!replay_esn->replay_window)
432 seq = ntohl(net_seq);
433 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
434 seq_hi = xfrm_replay_seqhi(x, net_seq);
435 wrap = seq_hi - replay_esn->seq_hi;
437 if ((!wrap && seq > replay_esn->seq) || wrap > 0) {
439 diff = seq - replay_esn->seq;
441 diff = ~replay_esn->seq + seq + 1;
443 if (diff < replay_esn->replay_window) {
444 for (i = 1; i < diff; i++) {
445 bitnr = (pos + i) % replay_esn->replay_window;
447 bitnr = bitnr & 0x1F;
448 replay_esn->bmp[nr] &= ~(1U << bitnr);
451 nr = (replay_esn->replay_window - 1) >> 5;
452 for (i = 0; i <= nr; i++)
453 replay_esn->bmp[i] = 0;
456 bitnr = (pos + diff) % replay_esn->replay_window;
457 replay_esn->seq = seq;
459 if (unlikely(wrap > 0))
460 replay_esn->seq_hi++;
462 diff = replay_esn->seq - seq;
465 bitnr = (pos - diff) % replay_esn->replay_window;
467 bitnr = replay_esn->replay_window - (diff - pos);
471 bitnr = bitnr & 0x1F;
472 replay_esn->bmp[nr] |= (1U << bitnr);
474 if (xfrm_aevent_is_on(xs_net(x)))
475 xfrm_replay_notify(x, XFRM_REPLAY_UPDATE);
478 static struct xfrm_replay xfrm_replay_legacy = {
479 .advance = xfrm_replay_advance,
480 .check = xfrm_replay_check,
481 .notify = xfrm_replay_notify,
482 .overflow = xfrm_replay_overflow,
485 static struct xfrm_replay xfrm_replay_bmp = {
486 .advance = xfrm_replay_advance_bmp,
487 .check = xfrm_replay_check_bmp,
488 .notify = xfrm_replay_notify_bmp,
489 .overflow = xfrm_replay_overflow_bmp,
492 static struct xfrm_replay xfrm_replay_esn = {
493 .advance = xfrm_replay_advance_esn,
494 .check = xfrm_replay_check_esn,
495 .notify = xfrm_replay_notify_bmp,
496 .overflow = xfrm_replay_overflow_esn,
499 int xfrm_init_replay(struct xfrm_state *x)
501 struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
504 if (replay_esn->replay_window >
505 replay_esn->bmp_len * sizeof(__u32) * 8)
508 if ((x->props.flags & XFRM_STATE_ESN) && replay_esn->replay_window == 0)
511 if ((x->props.flags & XFRM_STATE_ESN) && x->replay_esn)
512 x->repl = &xfrm_replay_esn;
514 x->repl = &xfrm_replay_bmp;
516 x->repl = &xfrm_replay_legacy;
520 EXPORT_SYMBOL(xfrm_init_replay);