From: Keita Suzuki <keitasuzuki.park@xxxxxxxxxxxxxxxxxxxx> commit 6b0d0477fce747d4137aa65856318b55fba72198 upstream. In function dvb_register_device() -> dvb_register_media_device() -> dvb_create_media_entity(), dvb->entity is allocated and initialized. If the initialization fails, it frees the dvb->entity, and return an error code. The caller takes the error code and handles the error by calling dvb_media_device_free(), which unregisters the entity and frees the field again if it is not NULL. As dvb->entity may not NULLed in dvb_create_media_entity() when the allocation of dvbdev->pad fails, a double free may occur. This may also cause an Use After free in media_device_unregister_entity(). Fix this by storing NULL to dvb->entity when it is freed. Link: https://lore.kernel.org/linux-media/20220426052921.2088416-1-keitasuzuki.park@xxxxxxxxxxxxxxxxxxxx Fixes: fcd5ce4b3936 ("media: dvb-core: fix a memory leak bug") Cc: stable@xxxxxxxxxxxxxxx Cc: Wenwen Wang <wenwen@xxxxxxxxxx> Signed-off-by: Keita Suzuki <keitasuzuki.park@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/media/dvb-core/dvbdev.c | 1 + 1 file changed, 1 insertion(+) --- a/drivers/media/dvb-core/dvbdev.c +++ b/drivers/media/dvb-core/dvbdev.c @@ -322,6 +322,7 @@ static int dvb_create_media_entity(struc GFP_KERNEL); if (!dvbdev->pads) { kfree(dvbdev->entity); + dvbdev->entity = NULL; return -ENOMEM; } }
