[PATCH 6.1 165/417] media: pvrusb2: fix use after free on context disconnection

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



6.1-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ricardo B. Marliere <ricardo@xxxxxxxxxxxx>

[ Upstream commit ded85b0c0edd8f45fec88783d7555a5b982449c1 ]

Upon module load, a kthread is created targeting the
pvr2_context_thread_func function, which may call pvr2_context_destroy
and thus call kfree() on the context object. However, that might happen
before the usb hub_event handler is able to notify the driver. This
patch adds a sanity check before the invalid read reported by syzbot,
within the context disconnection call stack.

Reported-and-tested-by: syzbot+621409285c4156a009b3@xxxxxxxxxxxxxxxxxxxxxxxxx
Closes: https://lore.kernel.org/all/000000000000a02a4205fff8eb92@xxxxxxxxxx/

Fixes: e5be15c63804 ("V4L/DVB (7711): pvrusb2: Fix race on module unload")
Signed-off-by: Ricardo B. Marliere <ricardo@xxxxxxxxxxxx>
Acked-by: Mike Isely <isely@xxxxxxxxx>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/media/usb/pvrusb2/pvrusb2-context.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/media/usb/pvrusb2/pvrusb2-context.c b/drivers/media/usb/pvrusb2/pvrusb2-context.c
index 14170a5d72b3..1764674de98b 100644
--- a/drivers/media/usb/pvrusb2/pvrusb2-context.c
+++ b/drivers/media/usb/pvrusb2/pvrusb2-context.c
@@ -268,7 +268,8 @@ void pvr2_context_disconnect(struct pvr2_context *mp)
 {
 	pvr2_hdw_disconnect(mp->hdw);
 	mp->disconnect_flag = !0;
-	pvr2_context_notify(mp);
+	if (!pvr2_context_shutok())
+		pvr2_context_notify(mp);
 }
 
 
-- 
2.43.0







[Index of Archives]     [Linux Kernel]     [Kernel Development Newbies]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite Hiking]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux