4.14-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit 34b1e0e9efe101822e83cc62d22443ed3867ae7a ]
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case, when TCP skb is being retransmitted, the pointer to the frag list is being reused, while the data in there is no longer valid.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 sara.sharon@intel.com Signed-off-by: Luca Coelho luciano.coelho@intel.com Signed-off-by: Johannes Berg johannes.berg@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- net/mac80211/status.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/net/mac80211/status.c b/net/mac80211/status.c index 35912270087c..b18466cf466c 100644 --- a/net/mac80211/status.c +++ b/net/mac80211/status.c @@ -545,6 +545,11 @@ static void ieee80211_report_used_skb(struct ieee80211_local *local, }
ieee80211_led_tx(local); + + if (skb_has_frag_list(skb)) { + kfree_skb_list(skb_shinfo(skb)->frag_list); + skb_shinfo(skb)->frag_list = NULL; + } }
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