mirror of https://gitee.com/openkylin/linux.git
xfrm: Support anti-replay window size bigger than 32 packets
As it is, the anti-replay bitmap in struct xfrm_replay_state can only accomodate 32 packets. Even though it is possible to configure anti-replay window sizes up to 255 packets from userspace. So we reject any packet with a sequence number within the configured window but outside the bitmap. With this patch, we represent the anti-replay window as a bitmap of variable length that can be accessed via the new struct xfrm_replay_state_esn. Thus, we have no limit on the window size anymore. To use the new anti-replay window implementantion, new userspace tools are required. We leave the old implementation untouched to stay in sync with old userspace tools. Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com> Acked-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Steffen Klassert
David S. Miller
parent
9fdc4883d9
commit
97e15c3a85
|
|
@ -1,5 +1,21 @@
|
|||
/*
|
||||
* xfrm_replay.c - xfrm replay detection, derived from xfrm_state.c.
|
||||
*
|
||||
* Copyright (C) 2010 secunet Security Networks AG
|
||||
* Copyright (C) 2010 Steffen Klassert <steffen.klassert@secunet.com>
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or modify it
|
||||
* under the terms and conditions of the GNU General Public License,
|
||||
* version 2, as published by the Free Software Foundation.
|
||||
*
|
||||
* This program is distributed in the hope it will be useful, but WITHOUT
|
||||
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
||||
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
|
||||
* more details.
|
||||
*
|
||||
* You should have received a copy of the GNU General Public License along with
|
||||
* this program; if not, write to the Free Software Foundation, Inc.,
|
||||
* 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
|
||||
*/
|
||||
|
||||
#include <net/xfrm.h>
|
||||
|
|
@ -125,6 +141,178 @@ static void xfrm_replay_advance(struct xfrm_state *x, __be32 net_seq)
|
|||
xfrm_replay_notify(x, XFRM_REPLAY_UPDATE);
|
||||
}
|
||||
|
||||
static int xfrm_replay_overflow_bmp(struct xfrm_state *x, struct sk_buff *skb)
|
||||
{
|
||||
int err = 0;
|
||||
struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
|
||||
struct net *net = xs_net(x);
|
||||
|
||||
if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
|
||||
XFRM_SKB_CB(skb)->seq.output.low = ++replay_esn->oseq;
|
||||
if (unlikely(replay_esn->oseq == 0)) {
|
||||
replay_esn->oseq--;
|
||||
xfrm_audit_state_replay_overflow(x, skb);
|
||||
err = -EOVERFLOW;
|
||||
|
||||
return err;
|
||||
}
|
||||
if (xfrm_aevent_is_on(net))
|
||||
x->repl->notify(x, XFRM_REPLAY_UPDATE);
|
||||
}
|
||||
|
||||
return err;
|
||||
}
|
||||
|
||||
static int xfrm_replay_check_bmp(struct xfrm_state *x,
|
||||
struct sk_buff *skb, __be32 net_seq)
|
||||
{
|
||||
unsigned int bitnr, nr;
|
||||
struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
|
||||
u32 seq = ntohl(net_seq);
|
||||
u32 diff = replay_esn->seq - seq;
|
||||
u32 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
|
||||
|
||||
if (unlikely(seq == 0))
|
||||
goto err;
|
||||
|
||||
if (likely(seq > replay_esn->seq))
|
||||
return 0;
|
||||
|
||||
if (diff >= replay_esn->replay_window) {
|
||||
x->stats.replay_window++;
|
||||
goto err;
|
||||
}
|
||||
|
||||
if (pos >= diff) {
|
||||
bitnr = (pos - diff) % replay_esn->replay_window;
|
||||
nr = bitnr >> 5;
|
||||
bitnr = bitnr & 0x1F;
|
||||
if (replay_esn->bmp[nr] & (1U << bitnr))
|
||||
goto err_replay;
|
||||
} else {
|
||||
bitnr = replay_esn->replay_window - (diff - pos);
|
||||
nr = bitnr >> 5;
|
||||
bitnr = bitnr & 0x1F;
|
||||
if (replay_esn->bmp[nr] & (1U << bitnr))
|
||||
goto err_replay;
|
||||
}
|
||||
return 0;
|
||||
|
||||
err_replay:
|
||||
x->stats.replay++;
|
||||
err:
|
||||
xfrm_audit_state_replay(x, skb, net_seq);
|
||||
return -EINVAL;
|
||||
}
|
||||
|
||||
static void xfrm_replay_advance_bmp(struct xfrm_state *x, __be32 net_seq)
|
||||
{
|
||||
unsigned int bitnr, nr, i;
|
||||
u32 diff;
|
||||
struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
|
||||
u32 seq = ntohl(net_seq);
|
||||
u32 pos = (replay_esn->seq - 1) % replay_esn->replay_window;
|
||||
|
||||
if (!replay_esn->replay_window)
|
||||
return;
|
||||
|
||||
if (seq > replay_esn->seq) {
|
||||
diff = seq - replay_esn->seq;
|
||||
|
||||
if (diff < replay_esn->replay_window) {
|
||||
for (i = 1; i < diff; i++) {
|
||||
bitnr = (pos + i) % replay_esn->replay_window;
|
||||
nr = bitnr >> 5;
|
||||
bitnr = bitnr & 0x1F;
|
||||
replay_esn->bmp[nr] &= ~(1U << bitnr);
|
||||
}
|
||||
|
||||
bitnr = (pos + diff) % replay_esn->replay_window;
|
||||
nr = bitnr >> 5;
|
||||
bitnr = bitnr & 0x1F;
|
||||
replay_esn->bmp[nr] |= (1U << bitnr);
|
||||
} else {
|
||||
nr = replay_esn->replay_window >> 5;
|
||||
for (i = 0; i <= nr; i++)
|
||||
replay_esn->bmp[i] = 0;
|
||||
|
||||
bitnr = (pos + diff) % replay_esn->replay_window;
|
||||
nr = bitnr >> 5;
|
||||
bitnr = bitnr & 0x1F;
|
||||
replay_esn->bmp[nr] |= (1U << bitnr);
|
||||
}
|
||||
|
||||
replay_esn->seq = seq;
|
||||
} else {
|
||||
diff = replay_esn->seq - seq;
|
||||
|
||||
if (pos >= diff) {
|
||||
bitnr = (pos - diff) % replay_esn->replay_window;
|
||||
nr = bitnr >> 5;
|
||||
bitnr = bitnr & 0x1F;
|
||||
replay_esn->bmp[nr] |= (1U << bitnr);
|
||||
} else {
|
||||
bitnr = replay_esn->replay_window - (diff - pos);
|
||||
nr = bitnr >> 5;
|
||||
bitnr = bitnr & 0x1F;
|
||||
replay_esn->bmp[nr] |= (1U << bitnr);
|
||||
}
|
||||
}
|
||||
|
||||
if (xfrm_aevent_is_on(xs_net(x)))
|
||||
xfrm_replay_notify(x, XFRM_REPLAY_UPDATE);
|
||||
}
|
||||
|
||||
static void xfrm_replay_notify_bmp(struct xfrm_state *x, int event)
|
||||
{
|
||||
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 &&
|
||||
(replay_esn->seq - preplay_esn->seq < x->replay_maxdiff) &&
|
||||
(replay_esn->oseq - preplay_esn->oseq < 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 struct xfrm_replay xfrm_replay_legacy = {
|
||||
.advance = xfrm_replay_advance,
|
||||
.check = xfrm_replay_check,
|
||||
|
|
@ -132,9 +320,26 @@ static struct xfrm_replay xfrm_replay_legacy = {
|
|||
.overflow = xfrm_replay_overflow,
|
||||
};
|
||||
|
||||
static struct xfrm_replay xfrm_replay_bmp = {
|
||||
.advance = xfrm_replay_advance_bmp,
|
||||
.check = xfrm_replay_check_bmp,
|
||||
.notify = xfrm_replay_notify_bmp,
|
||||
.overflow = xfrm_replay_overflow_bmp,
|
||||
};
|
||||
|
||||
int xfrm_init_replay(struct xfrm_state *x)
|
||||
{
|
||||
x->repl = &xfrm_replay_legacy;
|
||||
struct xfrm_replay_state_esn *replay_esn = x->replay_esn;
|
||||
|
||||
if (replay_esn) {
|
||||
if (replay_esn->replay_window >
|
||||
replay_esn->bmp_len * sizeof(__u32))
|
||||
return -EINVAL;
|
||||
|
||||
x->repl = &xfrm_replay_bmp;
|
||||
} else
|
||||
x->repl = &xfrm_replay_legacy;
|
||||
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
|
|
|||
Loading…
Reference in New Issue