lkml.org 
[lkml]   [2022]   [Jul]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] net: Fix UAF in ieee80211_scan_rx()
Date
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

\
 
 \ /
  Last update: 2022-07-01 16:56    [W:0.079 / U:0.972 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site