This is a note to let you know that I've just added the patch titled
i2c: Fix a potential use after free
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
i2c-fix-a-potential-use-after-free.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 01af03e0c494142cc17f26c51dbf5b38184af197
Author: Xu Wang <vulab@xxxxxxxxxxx>
Date: Fri Dec 27 09:34:32 2019 +0000
i2c: Fix a potential use after free
[ Upstream commit e4c72c06c367758a14f227c847f9d623f1994ecf ]
Free the adap structure only after we are done using it.
This patch just moves the put_device() down a bit to avoid the
use after free.
Fixes: 611e12ea0f12 ("i2c: core: manage i2c bus device refcount in i2c_[get|put]_adapter")
Signed-off-by: Xu Wang <vulab@xxxxxxxxxxx>
[wsa: added comment to the code, added Fixes tag]
Signed-off-by: Wolfram Sang <wsa@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index 2a43f4e46af0..9079be0d51d1 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -2273,8 +2273,9 @@ void i2c_put_adapter(struct i2c_adapter *adap)
if (!adap)
return;
- put_device(&adap->dev);
module_put(adap->owner);
+ /* Should be last, otherwise we risk use-after-free with 'adap' */
+ put_device(&adap->dev);
}
EXPORT_SYMBOL(i2c_put_adapter);
