]>
Commit | Line | Data |
---|---|---|
9fdc4883 SK |
1 | /* |
2 | * xfrm_replay.c - xfrm replay detection, derived from xfrm_state.c. | |
97e15c3a SK |
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. | |
9fdc4883 SK |
19 | */ |
20 | ||
bc3b2d7f | 21 | #include <linux/export.h> |
9fdc4883 SK |
22 | #include <net/xfrm.h> |
23 | ||
2cd08467 SK |
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 | ||
9fdc4883 SK |
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 | ||
36ae0148 SK |
122 | if (!x->props.replay_window) |
123 | return 0; | |
124 | ||
9fdc4883 SK |
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))) | |
1265fd61 | 170 | x->repl->notify(x, XFRM_REPLAY_UPDATE); |
9fdc4883 SK |
171 | } |
172 | ||
97e15c3a SK |
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; | |
36ae0148 | 200 | u32 pos; |
97e15c3a SK |
201 | u32 seq = ntohl(net_seq); |
202 | u32 diff = replay_esn->seq - seq; | |
36ae0148 SK |
203 | |
204 | if (!replay_esn->replay_window) | |
205 | return 0; | |
206 | ||
97e15c3a SK |
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 | ||
1d974374 SK |
218 | pos = (replay_esn->seq - 1) % replay_esn->replay_window; |
219 | ||
220 | if (pos >= diff) | |
97e15c3a | 221 | bitnr = (pos - diff) % replay_esn->replay_window; |
1d974374 | 222 | else |
97e15c3a | 223 | bitnr = replay_esn->replay_window - (diff - pos); |
1d974374 SK |
224 | |
225 | nr = bitnr >> 5; | |
226 | bitnr = bitnr & 0x1F; | |
227 | if (replay_esn->bmp[nr] & (1U << bitnr)) | |
228 | goto err_replay; | |
229 | ||
97e15c3a SK |
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 | } | |
97e15c3a | 260 | } else { |
e756682c | 261 | nr = (replay_esn->replay_window - 1) >> 5; |
97e15c3a SK |
262 | for (i = 0; i <= nr; i++) |
263 | replay_esn->bmp[i] = 0; | |
97e15c3a SK |
264 | } |
265 | ||
1d974374 | 266 | bitnr = (pos + diff) % replay_esn->replay_window; |
97e15c3a SK |
267 | replay_esn->seq = seq; |
268 | } else { | |
269 | diff = replay_esn->seq - seq; | |
270 | ||
1d974374 | 271 | if (pos >= diff) |
97e15c3a | 272 | bitnr = (pos - diff) % replay_esn->replay_window; |
1d974374 | 273 | else |
97e15c3a | 274 | bitnr = replay_esn->replay_window - (diff - pos); |
97e15c3a SK |
275 | } |
276 | ||
1d974374 SK |
277 | nr = bitnr >> 5; |
278 | bitnr = bitnr & 0x1F; | |
279 | replay_esn->bmp[nr] |= (1U << bitnr); | |
280 | ||
97e15c3a | 281 | if (xfrm_aevent_is_on(xs_net(x))) |
1265fd61 | 282 | x->repl->notify(x, XFRM_REPLAY_UPDATE); |
97e15c3a SK |
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 | ||
2cd08467 SK |
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; | |
36ae0148 | 370 | u32 pos; |
2cd08467 | 371 | u32 seq = ntohl(net_seq); |
2cd08467 SK |
372 | u32 wsize = replay_esn->replay_window; |
373 | u32 top = replay_esn->seq; | |
374 | u32 bottom = top - wsize + 1; | |
375 | ||
36ae0148 SK |
376 | if (!wsize) |
377 | return 0; | |
378 | ||
2cd08467 SK |
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 | ||
1d974374 SK |
402 | pos = (replay_esn->seq - 1) % replay_esn->replay_window; |
403 | ||
404 | if (pos >= diff) | |
2cd08467 | 405 | bitnr = (pos - diff) % replay_esn->replay_window; |
1d974374 | 406 | else |
2cd08467 | 407 | bitnr = replay_esn->replay_window - (diff - pos); |
1d974374 SK |
408 | |
409 | nr = bitnr >> 5; | |
410 | bitnr = bitnr & 0x1F; | |
411 | if (replay_esn->bmp[nr] & (1U << bitnr)) | |
412 | goto err_replay; | |
413 | ||
2cd08467 SK |
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 | ||
3b59df46 SK |
423 | static int xfrm_replay_recheck_esn(struct xfrm_state *x, |
424 | struct sk_buff *skb, __be32 net_seq) | |
425 | { | |
426 | if (unlikely(XFRM_SKB_CB(skb)->seq.input.hi != | |
427 | htonl(xfrm_replay_seqhi(x, net_seq)))) { | |
428 | x->stats.replay_window++; | |
429 | return -EINVAL; | |
430 | } | |
431 | ||
432 | return xfrm_replay_check_esn(x, skb, net_seq); | |
433 | } | |
434 | ||
2cd08467 SK |
435 | static void xfrm_replay_advance_esn(struct xfrm_state *x, __be32 net_seq) |
436 | { | |
437 | unsigned int bitnr, nr, i; | |
438 | int wrap; | |
439 | u32 diff, pos, seq, seq_hi; | |
440 | struct xfrm_replay_state_esn *replay_esn = x->replay_esn; | |
441 | ||
442 | if (!replay_esn->replay_window) | |
443 | return; | |
444 | ||
445 | seq = ntohl(net_seq); | |
446 | pos = (replay_esn->seq - 1) % replay_esn->replay_window; | |
447 | seq_hi = xfrm_replay_seqhi(x, net_seq); | |
448 | wrap = seq_hi - replay_esn->seq_hi; | |
449 | ||
450 | if ((!wrap && seq > replay_esn->seq) || wrap > 0) { | |
451 | if (likely(!wrap)) | |
452 | diff = seq - replay_esn->seq; | |
453 | else | |
454 | diff = ~replay_esn->seq + seq + 1; | |
455 | ||
456 | if (diff < replay_esn->replay_window) { | |
457 | for (i = 1; i < diff; i++) { | |
458 | bitnr = (pos + i) % replay_esn->replay_window; | |
459 | nr = bitnr >> 5; | |
460 | bitnr = bitnr & 0x1F; | |
461 | replay_esn->bmp[nr] &= ~(1U << bitnr); | |
462 | } | |
2cd08467 | 463 | } else { |
e756682c | 464 | nr = (replay_esn->replay_window - 1) >> 5; |
2cd08467 SK |
465 | for (i = 0; i <= nr; i++) |
466 | replay_esn->bmp[i] = 0; | |
2cd08467 SK |
467 | } |
468 | ||
1d974374 | 469 | bitnr = (pos + diff) % replay_esn->replay_window; |
2cd08467 SK |
470 | replay_esn->seq = seq; |
471 | ||
472 | if (unlikely(wrap > 0)) | |
473 | replay_esn->seq_hi++; | |
474 | } else { | |
475 | diff = replay_esn->seq - seq; | |
476 | ||
1d974374 | 477 | if (pos >= diff) |
2cd08467 | 478 | bitnr = (pos - diff) % replay_esn->replay_window; |
1d974374 | 479 | else |
2cd08467 | 480 | bitnr = replay_esn->replay_window - (diff - pos); |
2cd08467 SK |
481 | } |
482 | ||
1d974374 SK |
483 | nr = bitnr >> 5; |
484 | bitnr = bitnr & 0x1F; | |
485 | replay_esn->bmp[nr] |= (1U << bitnr); | |
486 | ||
2cd08467 | 487 | if (xfrm_aevent_is_on(xs_net(x))) |
1265fd61 | 488 | x->repl->notify(x, XFRM_REPLAY_UPDATE); |
2cd08467 SK |
489 | } |
490 | ||
9fdc4883 SK |
491 | static struct xfrm_replay xfrm_replay_legacy = { |
492 | .advance = xfrm_replay_advance, | |
493 | .check = xfrm_replay_check, | |
3b59df46 | 494 | .recheck = xfrm_replay_check, |
9fdc4883 SK |
495 | .notify = xfrm_replay_notify, |
496 | .overflow = xfrm_replay_overflow, | |
497 | }; | |
498 | ||
97e15c3a SK |
499 | static struct xfrm_replay xfrm_replay_bmp = { |
500 | .advance = xfrm_replay_advance_bmp, | |
501 | .check = xfrm_replay_check_bmp, | |
3b59df46 | 502 | .recheck = xfrm_replay_check_bmp, |
97e15c3a SK |
503 | .notify = xfrm_replay_notify_bmp, |
504 | .overflow = xfrm_replay_overflow_bmp, | |
505 | }; | |
506 | ||
2cd08467 SK |
507 | static struct xfrm_replay xfrm_replay_esn = { |
508 | .advance = xfrm_replay_advance_esn, | |
509 | .check = xfrm_replay_check_esn, | |
3b59df46 | 510 | .recheck = xfrm_replay_recheck_esn, |
2cd08467 SK |
511 | .notify = xfrm_replay_notify_bmp, |
512 | .overflow = xfrm_replay_overflow_esn, | |
513 | }; | |
514 | ||
9fdc4883 SK |
515 | int xfrm_init_replay(struct xfrm_state *x) |
516 | { | |
97e15c3a SK |
517 | struct xfrm_replay_state_esn *replay_esn = x->replay_esn; |
518 | ||
519 | if (replay_esn) { | |
520 | if (replay_esn->replay_window > | |
3f602b08 | 521 | replay_esn->bmp_len * sizeof(__u32) * 8) |
97e15c3a SK |
522 | return -EINVAL; |
523 | ||
6fa5ddcc SK |
524 | if ((x->props.flags & XFRM_STATE_ESN) && replay_esn->replay_window == 0) |
525 | return -EINVAL; | |
526 | ||
2cd08467 SK |
527 | if ((x->props.flags & XFRM_STATE_ESN) && x->replay_esn) |
528 | x->repl = &xfrm_replay_esn; | |
529 | else | |
97e15c3a SK |
530 | x->repl = &xfrm_replay_bmp; |
531 | } else | |
532 | x->repl = &xfrm_replay_legacy; | |
533 | ||
9fdc4883 SK |
534 | return 0; |
535 | } | |
536 | EXPORT_SYMBOL(xfrm_init_replay); |