From 31de381aef0ab1b342f62485118dc8a19363dc78 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Mon, 27 Sep 2021 11:58:39 +0200 Subject: [PATCH] mac80211: fix use-after-free in CCMP/GCMP RX 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.I1d066acd5408a662c3b6e828122cd314fcb28cdb@changeid Signed-off-by: Johannes Berg Signed-off-by: Greg Kroah-Hartman --- net/mac80211/wpa.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/net/mac80211/wpa.c b/net/mac80211/wpa.c index 7819a2507d39..b4d67ec50e63 100644 --- a/net/mac80211/wpa.c +++ b/net/mac80211/wpa.c @@ -514,6 +514,9 @@ 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; @@ -744,6 +747,9 @@ 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;