Commit 54552d03 authored by Alexander Aring's avatar Alexander Aring Committed by Marcel Holtmann

ieee802154: 6lowpan: check on valid 802.15.4 frame

This patch adds frame control checks to check if the received frame is
something which could contain a 6LoWPAN packet.
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 c6fdbba3
......@@ -205,6 +205,31 @@ enum {
IEEE802154_SCAN_IN_PROGRESS = 0xfc,
};
/* frame control handling */
#define IEEE802154_FCTL_FTYPE 0x0003
#define IEEE802154_FCTL_INTRA_PAN 0x0040
#define IEEE802154_FTYPE_DATA 0x0001
/*
* ieee802154_is_data - check if type is IEEE802154_FTYPE_DATA
* @fc: frame control bytes in little-endian byteorder
*/
static inline int ieee802154_is_data(__le16 fc)
{
return (fc & cpu_to_le16(IEEE802154_FCTL_FTYPE)) ==
cpu_to_le16(IEEE802154_FTYPE_DATA);
}
/**
* ieee802154_is_intra_pan - check if intra pan id communication
* @fc: frame control bytes in little-endian byteorder
*/
static inline bool ieee802154_is_intra_pan(__le16 fc)
{
return fc & cpu_to_le16(IEEE802154_FCTL_INTRA_PAN);
}
/**
* ieee802154_is_valid_psdu_len - check if psdu len is valid
* available lengths:
......
......@@ -249,6 +249,21 @@ struct ieee802154_ops {
const bool on);
};
/**
* ieee802154_get_fc_from_skb - get the frame control field from an skb
* @skb: skb where the frame control field will be get from
*/
static inline __le16 ieee802154_get_fc_from_skb(const struct sk_buff *skb)
{
/* return some invalid fc on failure */
if (unlikely(skb->mac_len < 2)) {
WARN_ON(1);
return cpu_to_le16(0);
}
return (__force __le16)__get_unaligned_memmove16(skb_mac_header(skb));
}
/**
* ieee802154_be64_to_le64 - copies and convert be64 to le64
* @le64_dst: le64 destination pointer
......
......@@ -11,6 +11,7 @@
#include <linux/if_arp.h>
#include <net/6lowpan.h>
#include <net/mac802154.h>
#include <net/ieee802154_netdev.h>
#include "6lowpan_i.h"
......@@ -280,6 +281,13 @@ static inline bool lowpan_is_reserved(u8 dispatch)
*/
static inline bool lowpan_rx_h_check(struct sk_buff *skb)
{
__le16 fc = ieee802154_get_fc_from_skb(skb);
/* check on ieee802154 conform 6LoWPAN header */
if (!ieee802154_is_data(fc) ||
!ieee802154_is_intra_pan(fc))
return false;
/* check if we can dereference the dispatch */
if (unlikely(!skb->len))
return false;
......
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