2021-07-10 18:39:00

by Davis

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Subject: [PATCH 4.14] mac80211: fix memory corruption in EAPOL handling

Commit 557bb37533a3 ("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: 557bb37533a3 ("mac80211: do not accept/forward invalid EAPOL frames")
Link: https://lore.kernel.org/r/[email protected]om
Cc: <[email protected]> # 4.14.x
Signed-off-by: Davis Mosenkovs <[email protected]>
---
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 ac2c52709e1c..87926c6fe0bf 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -2404,7 +2404,7 @@ 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);
--
2.25.1


2021-07-15 12:35:29

by Greg KH

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Subject: Re: [PATCH 4.14] mac80211: fix memory corruption in EAPOL handling

On Sat, Jul 10, 2021 at 09:38:07PM +0300, Davis Mosenkovs wrote:
> Commit 557bb37533a3 ("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: 557bb37533a3 ("mac80211: do not accept/forward invalid EAPOL frames")
> Link: https://lore.kernel.org/r/[email protected]om
> Cc: <[email protected]> # 4.14.x
> Signed-off-by: Davis Mosenkovs <[email protected]>
> ---
> net/mac80211/rx.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>

Ah, see your other backports now, nice, all now is good.

greg k-h