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xfrm: Fix replay notification for esn. 

We may miscalculate the sequence number difference from the
last time we send a notification if a sequence number wrap
occured in the meantime. We fix this by adding a separate
replay notify function for esn. Here we take the high bits
of the sequence number into account to calculate the
difference.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
This commit is contained in:
Steffen Klassert 2013-03-11 10:32:16 +01:00
parent 85dfb745ee
commit 0017c0b575
1 changed files with 67 additions and 1 deletions
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68
net/xfrm/xfrm_replay.c
View File

@ -334,6 +334,72 @@ static void xfrm_replay_notify_bmp(struct xfrm_state *x, int event)
x->xflags &= ~XFRM_TIME_DEFER;
}
static void xfrm_replay_notify_esn(struct xfrm_state *x, int event)
{
u32 seq_diff, oseq_diff;
struct km_event c;
struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
struct xfrm_replay_state_esn *preplay_esn = x->preplay_esn;
/* we send notify messages in case
* 1. we updated on of the sequence numbers, and the seqno difference
* is at least x->replay_maxdiff, in this case we also update the
* timeout of our timer function
* 2. if x->replay_maxage has elapsed since last update,
* and there were changes
*
* The state structure must be locked!
*/
switch (event) {
case XFRM_REPLAY_UPDATE:
if (!x->replay_maxdiff)
break;
if (replay_esn->seq_hi == preplay_esn->seq_hi)
seq_diff = replay_esn->seq - preplay_esn->seq;
else
seq_diff = UINT_MAX - preplay_esn->seq
+ replay_esn->seq;
if (replay_esn->oseq_hi == preplay_esn->oseq_hi)
oseq_diff = replay_esn->oseq - preplay_esn->oseq;
else
oseq_diff = UINT_MAX - preplay_esn->oseq
+ replay_esn->oseq;
if (seq_diff < x->replay_maxdiff &&
oseq_diff < x->replay_maxdiff) {
if (x->xflags & XFRM_TIME_DEFER)
event = XFRM_REPLAY_TIMEOUT;
else
return;
}
break;
case XFRM_REPLAY_TIMEOUT:
if (memcmp(x->replay_esn, x->preplay_esn,
xfrm_replay_state_esn_len(replay_esn)) == 0) {
x->xflags |= XFRM_TIME_DEFER;
return;
}
break;
}
memcpy(x->preplay_esn, x->replay_esn,
xfrm_replay_state_esn_len(replay_esn));
c.event = XFRM_MSG_NEWAE;
c.data.aevent = event;
km_state_notify(x, &c);
if (x->replay_maxage &&
!mod_timer(&x->rtimer, jiffies + x->replay_maxage))
x->xflags &= ~XFRM_TIME_DEFER;
}
static int xfrm_replay_overflow_esn(struct xfrm_state *x, struct sk_buff *skb)
{
int err = 0;
@ -510,7 +576,7 @@ static struct xfrm_replay xfrm_replay_esn = {
.advance = xfrm_replay_advance_esn,
.check = xfrm_replay_check_esn,
.recheck = xfrm_replay_recheck_esn,
.notify = xfrm_replay_notify_bmp,
.notify = xfrm_replay_notify_esn,
.overflow = xfrm_replay_overflow_esn,
};