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ieee802154: 6lowpan: add generic lowpan header check

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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: Stefan Schmidt <stefan@osg.samsung.com>
Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
This commit is contained in:
Alexander Aring 2015-09-02 14:21:26 +02:00 committed by Marcel Holtmann
parent 72a5e6bb51
commit faf7d36e5e
1 changed files with 27 additions and 1 deletions
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28
net/ieee802154/6lowpan/rx.c
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@ -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 @@ static int lowpan_invoke_rx_handlers(struct sk_buff *skb)
#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;