This is a note to let you know that I've just added the patch titled media: em28xx: Fix use-after-free in em28xx_alloc_urbs to the 5.4-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: media-em28xx-fix-use-after-free-in-em28xx_alloc_urbs.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 10680b12e37b77253812a0e94ae07bba114a3248 Author: Dinghao Liu <dinghao.liu@xxxxxxxxxx> Date: Mon Dec 28 14:02:05 2020 +0100 media: em28xx: Fix use-after-free in em28xx_alloc_urbs [ Upstream commit a26efd1961a18b91ae4cd2e433adbcf865b40fa3 ] When kzalloc() fails, em28xx_uninit_usb_xfer() will free usb_bufs->buf and set it to NULL. Thus the later access to usb_bufs->buf[i] will lead to null pointer dereference. Also the kfree(usb_bufs->buf) after that is redundant. Fixes: d571b592c6206 ("media: em28xx: don't use coherent buffer for DMA transfers") Signed-off-by: Dinghao Liu <dinghao.liu@xxxxxxxxxx> Signed-off-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/media/usb/em28xx/em28xx-core.c b/drivers/media/usb/em28xx/em28xx-core.c index e6088b5d1b805..3daa64bb1e1d9 100644 --- a/drivers/media/usb/em28xx/em28xx-core.c +++ b/drivers/media/usb/em28xx/em28xx-core.c @@ -956,14 +956,10 @@ int em28xx_alloc_urbs(struct em28xx *dev, enum em28xx_mode mode, int xfer_bulk, usb_bufs->buf[i] = kzalloc(sb_size, GFP_KERNEL); if (!usb_bufs->buf[i]) { - em28xx_uninit_usb_xfer(dev, mode); - for (i--; i >= 0; i--) kfree(usb_bufs->buf[i]); - kfree(usb_bufs->buf); - usb_bufs->buf = NULL; - + em28xx_uninit_usb_xfer(dev, mode); return -ENOMEM; }