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https://github.com/openwrt/openwrt.git
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56 lines
2.0 KiB
Diff
56 lines
2.0 KiB
Diff
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From 5d20c6f932f2758078d0454729129c894fe353e7 Mon Sep 17 00:00:00 2001
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From: Siddh Raman Pant <code@siddh.me>
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Date: Sat, 20 Aug 2022 01:33:40 +0530
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Subject: [PATCH] wifi: mac80211: Fix UAF in ieee80211_scan_rx()
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commit 60deb9f10eec5c6a20252ed36238b55d8b614a2c upstream.
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ieee80211_scan_rx() tries to access scan_req->flags after a
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null check, but a UAF is observed when the scan is completed
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and __ieee80211_scan_completed() executes, which then calls
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cfg80211_scan_done() leading to the freeing of scan_req.
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Since scan_req is rcu_dereference()'d, prevent the racing in
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__ieee80211_scan_completed() by ensuring that from mac80211's
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POV it is no longer accessed from an RCU read critical section
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before we call cfg80211_scan_done().
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Cc: stable@vger.kernel.org
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Link: https://syzkaller.appspot.com/bug?extid=f9acff9bf08a845f225d
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Reported-by: syzbot+f9acff9bf08a845f225d@syzkaller.appspotmail.com
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Suggested-by: Johannes Berg <johannes@sipsolutions.net>
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Signed-off-by: Siddh Raman Pant <code@siddh.me>
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Link: https://lore.kernel.org/r/20220819200340.34826-1-code@siddh.me
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Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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---
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net/mac80211/scan.c | 11 +++++++----
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1 file changed, 7 insertions(+), 4 deletions(-)
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--- a/net/mac80211/scan.c
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+++ b/net/mac80211/scan.c
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@@ -461,16 +461,19 @@ static void __ieee80211_scan_completed(s
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scan_req = rcu_dereference_protected(local->scan_req,
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lockdep_is_held(&local->mtx));
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- if (scan_req != local->int_scan_req) {
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- local->scan_info.aborted = aborted;
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- cfg80211_scan_done(scan_req, &local->scan_info);
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- }
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RCU_INIT_POINTER(local->scan_req, NULL);
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RCU_INIT_POINTER(local->scan_sdata, NULL);
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local->scanning = 0;
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local->scan_chandef.chan = NULL;
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+ synchronize_rcu();
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+
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+ if (scan_req != local->int_scan_req) {
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+ local->scan_info.aborted = aborted;
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+ cfg80211_scan_done(scan_req, &local->scan_info);
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+ }
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+
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/* Set power back to normal operating levels. */
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ieee80211_hw_config(local, 0);
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