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Commit faf7d36e authored by Alexander Aring's avatar Alexander Aring Committed by Marcel Holtmann
Browse files

ieee802154: 6lowpan: add generic lowpan header check 



This patch introduce an earlier check if a 6LoWPAN frame can be valid.
This contains at first for checking if the header contains a dispatch
byte and isn't the nalp dispatch value, which means it isn't a 6LoWPAN
packet. Also we add a check if we can derference the dispatch value by
checking if skb->len is unequal zero.

Reviewed-by: default avatarStefan Schmidt <stefan@osg.samsung.com>
Signed-off-by: default avatarAlexander Aring <alex.aring@gmail.com>
Signed-off-by: default avatarMarcel Holtmann <marcel@holtmann.org>
parent 72a5e6bb

net/ieee802154/6lowpan/rx.c

+27 −1
Original line number Diff line number Diff line
@@ -15,8 +15,11 @@ 


#include "6lowpan_i.h"



#define LOWPAN_DISPATCH_FIRST		0xc0

#define LOWPAN_DISPATCH_FRAG_MASK	0xf8



#define LOWPAN_DISPATCH_NALP		0x00



static int lowpan_give_skb_to_device(struct sk_buff *skb)

{

	skb->protocol = htons(ETH_P_IPV6);
@@ -162,13 +165,36 @@ rxh_next: 
#undef CALL_RXH

}



static inline bool lowpan_is_nalp(u8 dispatch)

{

	return (dispatch & LOWPAN_DISPATCH_FIRST) == LOWPAN_DISPATCH_NALP;

}



/* lowpan_rx_h_check checks on generic 6LoWPAN requirements

 * in MAC and 6LoWPAN header.

 *

 * Don't manipulate the skb here, it could be shared buffer.

 */

static inline bool lowpan_rx_h_check(struct sk_buff *skb)

{

	/* check if we can dereference the dispatch */

	if (unlikely(!skb->len))

		return false;



	if (lowpan_is_nalp(*skb_network_header(skb)))

		return false;



	return true;

}



static int lowpan_rcv(struct sk_buff *skb, struct net_device *wdev,

		      struct packet_type *pt, struct net_device *orig_wdev)

{

	struct net_device *ldev;



	if (wdev->type != ARPHRD_IEEE802154 ||

	    skb->pkt_type == PACKET_OTHERHOST)

	    skb->pkt_type == PACKET_OTHERHOST ||

	    !lowpan_rx_h_check(skb))

		return NET_RX_DROP;



	ldev = wdev->ieee802154_ptr->lowpan_dev;