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checkpatch: warn on use of yield()
[linux/fpc-iii.git] / net / xfrm / xfrm_replay.c
blob2f6d11d04a2b29910a1f284d3e3af8b0db1bfcce
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
24 u32 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
49 static 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
95 static 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
116 static 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
144 err:
145 xfrm_audit_state_replay(x, skb, net_seq);
146 return -EINVAL;
147 }
148
149 static 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
173 static 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
195 static 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
232 err_replay:
233 x->stats.replay++;
234 err:
235 xfrm_audit_state_replay(x, skb, net_seq);
236 return -EINVAL;
237 }
238
239 static 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
285 static 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
335 static 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
364 static 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
416 err_replay:
417 x->stats.replay++;
418 err:
419 xfrm_audit_state_replay(x, skb, net_seq);
420 return -EINVAL;
421 }
422
423 static 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
479 static 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
486 static 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
493 static 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
500 int 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 }
521 EXPORT_SYMBOL(xfrm_init_replay);
Linux with added FPC-III support