net/xfrm/xfrm_replay.c - linux - Git at Google

 /*
  * 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>

 static void xfrm_replay_notify(struct xfrm_state *x, int event)
 {
 	struct km_event c;
 	/* 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 &&
 		    (x->replay.seq - x->preplay.seq < x->replay_maxdiff) &&
 		    (x->replay.oseq - x->preplay.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, &x->preplay,
 			   sizeof(struct xfrm_replay_state)) == 0) {
 			x->xflags |= XFRM_TIME_DEFER;
 			return;
 		}

 		break;
 	}

 	memcpy(&x->preplay, &x->replay, sizeof(struct xfrm_replay_state));
 	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(struct xfrm_state *x, struct sk_buff *skb)
 {
 	int err = 0;
 	struct net *net = xs_net(x);

 	if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
 		XFRM_SKB_CB(skb)->seq.output.low = ++x->replay.oseq;
 		if (unlikely(x->replay.oseq == 0)) {
 			x->replay.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(struct xfrm_state *x,
 		      struct sk_buff *skb, __be32 net_seq)
 {
 	u32 diff;
 	u32 seq = ntohl(net_seq);

 	if (unlikely(seq == 0))
 		goto err;

 	if (likely(seq > x->replay.seq))
 		return 0;

 	diff = x->replay.seq - seq;
 	if (diff >= min_t(unsigned int, x->props.replay_window,
 			  sizeof(x->replay.bitmap) * 8)) {
 		x->stats.replay_window++;
 		goto err;
 	}

 	if (x->replay.bitmap & (1U << diff)) {
 		x->stats.replay++;
 		goto err;
 	}
 	return 0;

 err:
 	xfrm_audit_state_replay(x, skb, net_seq);
 	return -EINVAL;
 }

 static void xfrm_replay_advance(struct xfrm_state *x, __be32 net_seq)
 {
 	u32 diff;
 	u32 seq = ntohl(net_seq);

 	if (!x->props.replay_window)
 		return;

 	if (seq > x->replay.seq) {
 		diff = seq - x->replay.seq;
 		if (diff < x->props.replay_window)
 			x->replay.bitmap = ((x->replay.bitmap) << diff) | 1;
 		else
 			x->replay.bitmap = 1;
 		x->replay.seq = seq;
 	} else {
 		diff = x->replay.seq - seq;
 		x->replay.bitmap |= (1U << diff);
 	}

 	if (xfrm_aevent_is_on(xs_net(x)))
 		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,
 	.notify		= xfrm_replay_notify,
 	.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)
 {
 	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;
 }
 EXPORT_SYMBOL(xfrm_init_replay);
	/*
	* 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>

	static void xfrm_replay_notify(struct xfrm_state *x, int event)
	{
	struct km_event c;
	/* 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 &&
	(x->replay.seq - x->preplay.seq < x->replay_maxdiff) &&
	(x->replay.oseq - x->preplay.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, &x->preplay,
	sizeof(struct xfrm_replay_state)) == 0) {
	x->xflags \|= XFRM_TIME_DEFER;
	return;
	}

	break;
	}

	memcpy(&x->preplay, &x->replay, sizeof(struct xfrm_replay_state));
	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(struct xfrm_state x, struct sk_buff skb)
	{
	int err = 0;
	struct net *net = xs_net(x);

	if (x->type->flags & XFRM_TYPE_REPLAY_PROT) {
	XFRM_SKB_CB(skb)->seq.output.low = ++x->replay.oseq;
	if (unlikely(x->replay.oseq == 0)) {
	x->replay.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(struct xfrm_state *x,
	struct sk_buff *skb, __be32 net_seq)
	{
	u32 diff;
	u32 seq = ntohl(net_seq);

	if (unlikely(seq == 0))
	goto err;

	if (likely(seq > x->replay.seq))
	return 0;

	diff = x->replay.seq - seq;
	if (diff >= min_t(unsigned int, x->props.replay_window,
	sizeof(x->replay.bitmap) * 8)) {
	x->stats.replay_window++;
	goto err;
	}

	if (x->replay.bitmap & (1U << diff)) {
	x->stats.replay++;
	goto err;
	}
	return 0;

	err:
	xfrm_audit_state_replay(x, skb, net_seq);
	return -EINVAL;
	}

	static void xfrm_replay_advance(struct xfrm_state *x, __be32 net_seq)
	{
	u32 diff;
	u32 seq = ntohl(net_seq);

	if (!x->props.replay_window)
	return;

	if (seq > x->replay.seq) {
	diff = seq - x->replay.seq;
	if (diff < x->props.replay_window)
	x->replay.bitmap = ((x->replay.bitmap) << diff) \| 1;
	else
	x->replay.bitmap = 1;
	x->replay.seq = seq;
	} else {
	diff = x->replay.seq - seq;
	x->replay.bitmap \|= (1U << diff);
	}

	if (xfrm_aevent_is_on(xs_net(x)))
	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,
	.notify = xfrm_replay_notify,
	.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)
	{
	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;
	}
	EXPORT_SYMBOL(xfrm_init_replay);