peci: cpu: Fix use-after-free in adev_release()

When auxiliary_device_add() returns an error, auxiliary_device_uninit()
is called, which causes refcount for device to be decremented and
.release callback will be triggered.

Because adev_release() re-calls auxiliary_device_uninit(), it will cause
use-after-free:
[ 1269.455172] WARNING: CPU: 0 PID: 14267 at lib/refcount.c:28 refcount_warn_saturate+0x110/0x15
[ 1269.464007] refcount_t: underflow; use-after-free.

Reported-by: Jianglei Nie <niejianglei2021@163.com>
Signed-off-by: Iwona Winiarska <iwona.winiarska@intel.com>
Link: https://lore.kernel.org/r/20220705101501.298395-1-iwona.winiarska@intel.com

diff --git a/drivers/peci/cpu.c b/drivers/peci/cpu.c
index 68eb61c65d345f20a6d3fac0d5723a7dd0b9269e..de4a7b3e5966ede8ddeb8bf2262f6f1024510023 100644 (file)
--- a/drivers/peci/cpu.c
+++ b/drivers/peci/cpu.c
@@ -188,8 +188,6 @@ static void adev_release(struct device *dev)
 {
        struct auxiliary_device *adev = to_auxiliary_dev(dev);
 
-       auxiliary_device_uninit(adev);
-
        kfree(adev->name);
        kfree(adev);
 }
@@ -234,6 +232,7 @@ static void unregister_adev(void *_adev)
        struct auxiliary_device *adev = _adev;
 
        auxiliary_device_delete(adev);
+       auxiliary_device_uninit(adev);
 }
 
 static int devm_adev_add(struct device *dev, int idx)