Commit 1dc8b65c authored by Arnd Bergmann's avatar Arnd Bergmann Committed by Mauro Carvalho Chehab
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media: v4l2-core: only zero-out ioctl-read buffers 



The memset() got moved out of the check for _IOC_NONE, so passing a
made-up command number with a size but no direction would allow clearing
data on user-provided pointers.

Move video_get_user() back into the _IOC_NONE check where it belongs.

Reported-by: default avatar <syzbot+54fd8cca4b7226c94b8e@syzkaller.appspotmail.com>
Fixes: 6c625c01c7a6 ("media: v4l2-core: split out data copy from video_usercopy")
Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarHans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab+huawei@kernel.org>
parent e4b9b645

drivers/media/v4l2-core/v4l2-ioctl.c

+4 −4
Original line number Diff line number Diff line
@@ -3205,11 +3205,11 @@ video_usercopy(struct file *file, unsigned int orig_cmd, unsigned long arg, 
			parg = mbuf;

		}



	}



	err = video_get_user((void __user *)arg, parg, orig_cmd, &always_copy);

		err = video_get_user((void __user *)arg, parg, orig_cmd,

				     &always_copy);

		if (err)

			goto out;

	}



	err = check_array_args(cmd, parg, &array_size, &user_ptr, &kernel_ptr);

	if (err < 0)