i2c: Fix a potential use after free

[ Upstream commit e4c72c06c3 ]

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: 611e12ea0f ("i2c: core: manage i2c bus device refcount in i2c_[get|put]_adapter")
Signed-off-by: Xu Wang <vulab@iscas.ac.cn>
[wsa: added comment to the code, added Fixes tag]
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Xu Wang 2019-12-27 09:34:32 +00:00 committed by Greg Kroah-Hartman
parent 8b4bba610f
commit 35927d7509

View file

@ -2464,8 +2464,9 @@ 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);