wifi: mac80211: Fix UAF in ieee80211_scan_rx()
authorSiddh Raman Pant <code@siddh.me>
Fri, 19 Aug 2022 20:03:40 +0000 (01:33 +0530)
committerJohannes Berg <johannes.berg@intel.com>
Thu, 25 Aug 2022 08:00:21 +0000 (10:00 +0200)
commit60deb9f10eec5c6a20252ed36238b55d8b614a2c
tree9a372137cd50ef90756915e2a8f9543059ccca0c
parent24c7a64ea4764d70e4ac9b0a60ecd9b03c68435e
wifi: mac80211: Fix UAF in ieee80211_scan_rx()

ieee80211_scan_rx() tries to access scan_req->flags after a
null check, but a UAF is observed when the scan is completed
and __ieee80211_scan_completed() executes, which then calls
cfg80211_scan_done() leading to the freeing of scan_req.

Since scan_req is rcu_dereference()'d, prevent the racing in
__ieee80211_scan_completed() by ensuring that from mac80211's
POV it is no longer accessed from an RCU read critical section
before we call cfg80211_scan_done().

Cc: stable@vger.kernel.org
Link: https://syzkaller.appspot.com/bug?extid=f9acff9bf08a845f225d
Reported-by: syzbot+f9acff9bf08a845f225d@syzkaller.appspotmail.com
Suggested-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Siddh Raman Pant <code@siddh.me>
Link: https://lore.kernel.org/r/20220819200340.34826-1-code@siddh.me
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
net/mac80211/scan.c