Re: [PATCH v4] mac80211: fix control port tx status check

[Johannes Berg <johannes@sipsolutions.net>]

On Thu, 2020-06-25 at 10:48 +0200, Markus Theil wrote:
> The initial control port tx status patch assumed, that
> we have IEEE 802.11 frames, but actually ethernet frames
> are stored in the ack skb. Fix this by checking for the
> correct ethertype and skb protocol 802.3.
> 
> Also allow tx status reports for ETH_P_PREAUTH, as preauth
> frames can also be send over the nl80211 control port.
> 
> Fixes: a7528198add8 ("mac80211: support control port TX status reporting")
> Reported-by: kernel test robot <lkp@intel.com>
> Reported-by: Jouni Malinen <j@w1.fi>
> Signed-off-by: Markus Theil <markus.theil@tu-ilmenau.de>
> ---
> v4: add cast, reported by Intel kernel test robot
> v3: also check for ETH_P_PREAUTH
> v2: use __be16, as suggested by Johannes Berg
>  net/mac80211/status.c | 22 +++++++++++++++-------
>  1 file changed, 15 insertions(+), 7 deletions(-)
> 
> diff --git a/net/mac80211/status.c b/net/mac80211/status.c
> index 7b1bacac39c6..d6edd3acda0a 100644
> --- a/net/mac80211/status.c
> +++ b/net/mac80211/status.c
> @@ -639,11 +639,23 @@ static void ieee80211_report_ack_skb(struct ieee80211_local *local,
>  		u64 cookie = IEEE80211_SKB_CB(skb)->ack.cookie;
>  		struct ieee80211_sub_if_data *sdata;
>  		struct ieee80211_hdr *hdr = (void *)skb->data;
> +		__be16 ethertype = (__be16)0xffff;

If anything, that should've been "cpu_to_be16(0xffff)" but I was just
applying this and changing it to 0 instead (which sparse knows about).

johannes