1 files changed, 41 insertions, 0 deletions
diff --git a/package/kernel/mac80211/patches/350-mac80211-init-fastxmit-later.patch b/package/kernel/mac80211/patches/350-mac80211-init-fastxmit-later.patch
new file mode 100644
index 0000000000..0b640efea9
--- /dev/null
+++ b/package/kernel/mac80211/patches/350-mac80211-init-fastxmit-later.patch
@@ -0,0 +1,41 @@
+From 35f432a03e41d3bf08c51ede917f94e2288fbe8c Mon Sep 17 00:00:00 2001
+From: Johannes Berg <johannes.berg@intel.com>
+Date: Mon, 2 Jan 2017 11:19:29 +0100
+Subject: [PATCH] mac80211: initialize fast-xmit 'info' later
+
+In ieee80211_xmit_fast(), 'info' is initialized to point to the skb
+that's passed in, but that skb may later be replaced by a clone (if
+it was shared), leading to an invalid pointer.
+
+This can lead to use-after-free and also later crashes since the
+real SKB's info->hw_queue doesn't get initialized properly.
+
+Fix this by assigning info only later, when it's needed, after the
+skb replacement (may have) happened.
+
+Cc: stable@vger.kernel.org
+Reported-by: Ben Greear <greearb@candelatech.com>
+Signed-off-by: Johannes Berg <johannes.berg@intel.com>
+---
+ net/mac80211/tx.c | 3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+--- a/net/mac80211/tx.c
++++ b/net/mac80211/tx.c
+@@ -3297,7 +3297,7 @@ static bool ieee80211_xmit_fast(struct i
+ 	int extra_head = fast_tx->hdr_len - (ETH_HLEN - 2);
+ 	int hw_headroom = sdata->local->hw.extra_tx_headroom;
+ 	struct ethhdr eth;
+-	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
++	struct ieee80211_tx_info *info;
+ 	struct ieee80211_hdr *hdr = (void *)fast_tx->hdr;
+ 	struct ieee80211_tx_data tx;
+ 	ieee80211_tx_result r;
+@@ -3361,6 +3361,7 @@ static bool ieee80211_xmit_fast(struct i
+ 	memcpy(skb->data + fast_tx->da_offs, eth.h_dest, ETH_ALEN);
+ 	memcpy(skb->data + fast_tx->sa_offs, eth.h_source, ETH_ALEN);
+ 
++	info = IEEE80211_SKB_CB(skb);
+ 	memset(info, 0, sizeof(*info));
+ 	info->band = fast_tx->band;
+ 	info->control.vif = &sdata->vif;