[rt2x00-users] [PATCH 04/12] mac80211: improved ieee80211_verify_alignment

[Ivo van Doorn]

On Saturday 29 August 2009, Benoit PAPILLAULT wrote:
> ieee80211_verify_alignment has been improved to avoid small 802.11 frame (<2
> bytes) and skip checking for data alignment when there is no 802.11 data (when
> the frame length is less or egal to the header length)
> 
> Signed-off-by: Benoit PAPILLAULT <benoit.papillault at free.fr>

Please send this patch to the linux-wireless mailinglist.
There Johannes Berg can review and ACK/NACK your patch.

Thanks,

Ivo

> ---
>  net/mac80211/rx.c |   13 +++++++++++++
>  1 files changed, 13 insertions(+), 0 deletions(-)
> 
> diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
> index 4cd9e45..4cd0c7d 100644
> --- a/net/mac80211/rx.c
> +++ b/net/mac80211/rx.c
> @@ -399,10 +399,23 @@ static void ieee80211_verify_alignment(struct ieee80211_rx_data *rx)
>  		      "unaligned packet at 0x%p\n", rx->skb->data))
>  		return;
>  
> +	/* before using the hdr->frame_control field, we need to check that
> +	 * skb contains at least 2 bytes */
> +
> +	if (rx->skb->len < 2)
> +		return ;
> +
>  	if (!ieee80211_is_data_present(hdr->frame_control))
>  		return;
>  
>  	hdrlen = ieee80211_hdrlen(hdr->frame_control);
> +
> +	/* before checking data alignment, we need to check that skb contains
> +	 * at least 1 byte of data */
> +
> +	if (rx->skb->len <= hdrlen)
> +		return;
> +
>  	if (rx->flags & IEEE80211_RX_AMSDU)
>  		hdrlen += ETH_HLEN;
>  	WARN_ONCE(((unsigned long)(rx->skb->data + hdrlen)) & 3,