ACK/cmnt: [SRU Bionic PATCH 1/1] mac80211: fix memory corruption in EAPOL handling

[Juerg Haefliger]

On Wed, 28 Jul 2021 16:36:38 +0200
Stefan Bader <stefan.bader at canonical.com> wrote:

> From: Davis Mosenkovs <davis at mosenkovs.lv>
> 
> BugLink: https://bugs.launchpad.net/bugs/1938013
> 
> Commit e3d4030498c3 ("mac80211: do not accept/forward invalid EAPOL
> frames") uses skb_mac_header() before eth_type_trans() is called
> leading to incorrect pointer, the pointer gets written to. This issue
> has appeared during backporting to 4.4, 4.9 and 4.14.
> 
> Fixes: e3d4030498c3 ("mac80211: do not accept/forward invalid EAPOL frames")
> Link: https://lore.kernel.org/r/CAHQn7pKcyC_jYmGyTcPCdk9xxATwW5QPNph=bsZV8d-HPwNsyA@mail.gmail.com
> Cc: <stable at vger.kernel.org> # 4.4.x
> Signed-off-by: Davis Mosenkovs <davis at mosenkovs.lv>
> Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
> 
> (cherry picked from commit 3b6d3d1884fa31f701603772732c404020b0598d linux.4.14.y)

Nit: Should be linux-4.14.y.


> Signed-off-by: Stefan Bader <stefan.bader at canonical.com>
> Tested-by: Juerg Haefliger <juerg.haefliger at canonical.com>

Acked-by: Juerg Haefliger <juergh at canonical.com>


> ---
>  net/mac80211/rx.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
> index 95e6d41626d6..7847b168c9ce 100644
> --- a/net/mac80211/rx.c
> +++ b/net/mac80211/rx.c
> @@ -2407,7 +2407,7 @@ ieee80211_deliver_skb(struct ieee80211_rx_data *rx)
>  #endif
>  
>  	if (skb) {
> -		struct ethhdr *ehdr = (void *)skb_mac_header(skb);
> +		struct ethhdr *ehdr = (struct ethhdr *)skb->data;
>  
>  		/* deliver to local stack */
>  		skb->protocol = eth_type_trans(skb, dev);

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