From: Johannes Berg johannes.berg@intel.com
When PN checking is done in mac80211, for fragmentation we need to copy the PN to the RX struct so we can later use it to do a comparison, since commit bf30ca922a0c ("mac80211: check defrag PN against current frame").
Unfortunately, in that commit I used the 'hdr' variable without it being necessarily valid, so use-after-free could occur if it was necessary to reallocate (parts of) the frame.
Fix this by reloading the variable after the code that results in the reallocations, if any.
This fixes https://bugzilla.kernel.org/show_bug.cgi?id=214401.
Cc: stable@vger.kernel.org Fixes: bf30ca922a0c ("mac80211: check defrag PN against current frame") Signed-off-by: Johannes Berg johannes.berg@intel.com --- net/mac80211/wpa.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/net/mac80211/wpa.c b/net/mac80211/wpa.c index bca47fad5a16..4eed23e27610 100644 --- a/net/mac80211/wpa.c +++ b/net/mac80211/wpa.c @@ -520,6 +520,9 @@ ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx, return RX_DROP_UNUSABLE; }
+ /* reload hdr - skb might have been reallocated */ + hdr = (void *)rx->skb->data; + data_len = skb->len - hdrlen - IEEE80211_CCMP_HDR_LEN - mic_len; if (!rx->sta || data_len < 0) return RX_DROP_UNUSABLE; @@ -749,6 +752,9 @@ ieee80211_crypto_gcmp_decrypt(struct ieee80211_rx_data *rx) return RX_DROP_UNUSABLE; }
+ /* reload hdr - skb might have been reallocated */ + hdr = (void *)rx->skb->data; + data_len = skb->len - hdrlen - IEEE80211_GCMP_HDR_LEN - mic_len; if (!rx->sta || data_len < 0) return RX_DROP_UNUSABLE;