2021-07-10 18:38:25

by Davis

[permalink] [raw]
Subject: [PATCH 4.9] mac80211: fix memory corruption in EAPOL handling

Commit 5551cb1c68d4 ("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: 5551cb1c68d4 ("mac80211: do not accept/forward invalid EAPOL frames")
Link: https://lore.kernel.org/r/[email protected]om
Cc: <[email protected]> # 4.9.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 3a069cb188b7..b40e71a5d795 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -2380,7 +2380,7 @@ 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