From: Johannes Berg johannes.berg@intel.com
commit 94513069eb549737bcfc3d988d6ed4da948a2de8 upstream.
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") Link: https://lore.kernel.org/r/20210927115838.12b9ac6bb233.I1d066acd5408a662c3b6e... Signed-off-by: Johannes Berg johannes.berg@intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/mac80211/wpa.c | 6 ++++++ 1 file changed, 6 insertions(+)
--- a/net/mac80211/wpa.c +++ b/net/mac80211/wpa.c @@ -514,6 +514,9 @@ ieee80211_crypto_ccmp_decrypt(struct iee 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; @@ -744,6 +747,9 @@ ieee80211_crypto_gcmp_decrypt(struct iee 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;