From: Felix Fietkau Date: Thu, 11 Oct 2018 16:48:35 +0000 (+0200) Subject: mac80211: fix A-MSDU packet handling with TCP retransmission X-Git-Tag: v18.06.2~327 X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=4fa4b5edaf79a3574e1485ebb04ba7e0d2289d63;p=openwrt%2Fstaging%2Fchunkeey.git mac80211: fix A-MSDU packet handling with TCP retransmission Improves local TCP throughput and fixes use-after-free bugs that could lead to crashes. Signed-off-by: Felix Fietkau --- diff --git a/package/kernel/mac80211/patches/396-mac80211-free-skb-fraglist-before-freeing-the-skb.patch b/package/kernel/mac80211/patches/396-mac80211-free-skb-fraglist-before-freeing-the-skb.patch new file mode 100644 index 0000000000..4819dfc648 --- /dev/null +++ b/package/kernel/mac80211/patches/396-mac80211-free-skb-fraglist-before-freeing-the-skb.patch @@ -0,0 +1,31 @@ +From: Sara Sharon +Date: Thu, 11 Oct 2018 14:21:21 +0200 +Subject: [PATCH] mac80211: free skb fraglist before freeing the skb + +mac80211 uses the frag list to build AMSDU. When freeing +the skb, it may not be really freed, since someone is still +holding a reference to it. +In that case, when TCP skb is being retransmitted, the +pointer to the frag list is being reused, while the data +in there is no longer valid. +Since we will never get frag list from the network stack, +as mac80211 doesn't advertise the capability, we can safely +free and nullify it before releasing the SKB. + +Signed-off-by: Sara Sharon +--- + +--- a/net/mac80211/status.c ++++ b/net/mac80211/status.c +@@ -550,6 +550,11 @@ static void ieee80211_report_used_skb(st + } + + ieee80211_led_tx(local); ++ ++ if (skb_has_frag_list(skb)) { ++ kfree_skb_list(skb_shinfo(skb)->frag_list); ++ skb_shinfo(skb)->frag_list = NULL; ++ } + } + + /*