From: Siddh Raman Pant <code@siddh.me>
To: Johannes Berg <johannes@sipsolutions.net>,
"David S . Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>
Cc: linux-wireless <linux-wireless@vger.kernel.org>,
netdev <netdev@vger.kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
linux-kernel-mentees
<linux-kernel-mentees@lists.linuxfoundation.org>
Subject: [PATCH] net: Fix UAF in ieee80211_scan_rx()
Date: Fri, 1 Jul 2022 20:24:23 +0530 [thread overview]
Message-ID: <20220701145423.53208-1-code@siddh.me> (raw)
ieee80211_scan_rx() tries to access scan_req->flags after a null check
(see line 303 of mac80211/scan.c), but ___cfg80211_scan_done() uses
kfree() on the scan_req (see line 991 of wireless/scan.c).
This results in a UAF.
ieee80211_scan_rx() is called inside a RCU read-critical section
initiated by ieee80211_rx_napi() (see line 5043 of mac80211/rx.c).
Thus, add an rcu_head to the scan_req struct so as to use kfree_rcu()
instead of kfree() so that we don't free during the critical section.
Bug report (3): https://syzkaller.appspot.com/bug?extid=f9acff9bf08a845f225d
Reported-by: syzbot+f9acff9bf08a845f225d@syzkaller.appspotmail.com
Reported-by: syzbot+6cb476b7c69916a0caca@syzkaller.appspotmail.com
Reported-by: syzbot+9250865a55539d384347@syzkaller.appspotmail.com
Signed-off-by: Siddh Raman Pant <code@siddh.me>
---
include/net/cfg80211.h | 2 ++
net/wireless/scan.c | 2 +-
2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 6d02e12e4702..ba4a49884de8 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -2368,6 +2368,7 @@ struct cfg80211_scan_6ghz_params {
* @n_6ghz_params: number of 6 GHz params
* @scan_6ghz_params: 6 GHz params
* @bssid: BSSID to scan for (most commonly, the wildcard BSSID)
+ * @rcu_head: (internal) RCU head to use for freeing
*/
struct cfg80211_scan_request {
struct cfg80211_ssid *ssids;
@@ -2397,6 +2398,7 @@ struct cfg80211_scan_request {
bool scan_6ghz;
u32 n_6ghz_params;
struct cfg80211_scan_6ghz_params *scan_6ghz_params;
+ struct rcu_head rcu_head;
/* keep last */
struct ieee80211_channel *channels[];
diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index 6d82bd9eaf8c..638b2805222c 100644
--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -988,7 +988,7 @@ void ___cfg80211_scan_done(struct cfg80211_registered_device *rdev,
kfree(rdev->int_scan_req);
rdev->int_scan_req = NULL;
- kfree(rdev->scan_req);
+ kfree_rcu(rdev->scan_req, rcu_head);
rdev->scan_req = NULL;
if (!send_message)
--
2.35.1
next reply other threads:[~2022-07-01 15:11 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-01 14:54 Siddh Raman Pant [this message]
2022-07-07 11:36 ` Ping: [PATCH] net: Fix UAF in ieee80211_scan_rx() Siddh Raman Pant
2022-07-07 11:50 ` Greg KH
2022-07-07 11:59 ` Siddh Raman Pant
2022-07-26 9:55 ` Kalle Valo
2022-07-26 11:50 ` Siddh Raman Pant
2022-07-26 10:07 ` Eric Dumazet
2022-07-26 12:16 ` Siddh Raman Pant
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