Fixes for 4.9

Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/queue-4.9/series b/queue-4.9/series
index 07b4a3ea52bf67481deb12c044f7ab96596e13ce..49b7875186eb52524ddc5d2132609c4b4770d162 100644 (file)
--- a/queue-4.9/series
+++ b/queue-4.9/series
@@ -10,3 +10,4 @@ mips-lantiq-xway-fix-refcount-leak-bug-in-sysctrl.patch
 mips-pic32-pic32mzda-fix-refcount-leak-bugs.patch
 mips-lantiq-add-missing-of_node_put-in-irq.c.patch
 arm-mach-spear-add-missing-of_node_put-in-time.c.patch
+wifi-mac80211-fix-uaf-in-ieee80211_scan_rx.patch

diff --git a/queue-4.9/wifi-mac80211-fix-uaf-in-ieee80211_scan_rx.patch b/queue-4.9/wifi-mac80211-fix-uaf-in-ieee80211_scan_rx.patch
new file mode 100644 (file)
index 0000000..e4feccc
--- /dev/null
+++ b/queue-4.9/wifi-mac80211-fix-uaf-in-ieee80211_scan_rx.patch
@@ -0,0 +1,63 @@
+From 964052e29e113e6f529e9ff1824b739ed86518f6 Mon Sep 17 00:00:00 2001
+From: Sasha Levin <sashal@kernel.org>
+Date: Sat, 20 Aug 2022 01:33:40 +0530
+Subject: wifi: mac80211: Fix UAF in ieee80211_scan_rx()
+
+From: Siddh Raman Pant <code@siddh.me>
+
+[ Upstream commit 60deb9f10eec5c6a20252ed36238b55d8b614a2c ]
+
+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>
+Signed-off-by: Sasha Levin <sashal@kernel.org>
+---
+ net/mac80211/scan.c | 11 +++++++----
+ 1 file changed, 7 insertions(+), 4 deletions(-)
+
+diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c
+index 701adcb9262e..a73c362a0182 100644
+--- a/net/mac80211/scan.c
++++ b/net/mac80211/scan.c
+@@ -385,10 +385,6 @@ static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
+       scan_req = rcu_dereference_protected(local->scan_req,
+                                            lockdep_is_held(&local->mtx));
+ 
+-      if (scan_req != local->int_scan_req) {
+-              local->scan_info.aborted = aborted;
+-              cfg80211_scan_done(scan_req, &local->scan_info);
+-      }
+       RCU_INIT_POINTER(local->scan_req, NULL);
+ 
+       scan_sdata = rcu_dereference_protected(local->scan_sdata,
+@@ -398,6 +394,13 @@ static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
+       local->scanning = 0;
+       local->scan_chandef.chan = NULL;
+ 
++      synchronize_rcu();
++
++      if (scan_req != local->int_scan_req) {
++              local->scan_info.aborted = aborted;
++              cfg80211_scan_done(scan_req, &local->scan_info);
++      }
++
+       /* Set power back to normal operating levels. */
+       ieee80211_hw_config(local, 0);
+ 
+-- 
+2.35.1
+