From 123eddf92a114e03919942641d2c2b1f4ca56ea6 Mon Sep 17 00:00:00 2001 From: Keita Suzuki Date: Tue, 26 Apr 2022 06:29:19 +0100 Subject: [PATCH] media: dvb-core: Fix double free in dvb_register_device() 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@sslab.ics.keio.ac.jp Fixes: fcd5ce4b3936 ("media: dvb-core: fix a memory leak bug") Cc: stable@vger.kernel.org Cc: Wenwen Wang Signed-off-by: Keita Suzuki Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Greg Kroah-Hartman --- drivers/media/dvb-core/dvbdev.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/media/dvb-core/dvbdev.c b/drivers/media/dvb-core/dvbdev.c index 9934728..a31d52c 100644 --- a/drivers/media/dvb-core/dvbdev.c +++ b/drivers/media/dvb-core/dvbdev.c @@ -335,6 +335,7 @@ static int dvb_create_media_entity(struct dvb_device *dvbdev, GFP_KERNEL); if (!dvbdev->pads) { kfree(dvbdev->entity); + dvbdev->entity = NULL; return -ENOMEM; } } -- 2.7.4