Commit a014741c authored Nov 08, 2010 by Vasiliy Kulikov Committed by Jens Axboe Nov 10, 2010

block: ioctl: fix information leak to userland



Structure hd_geometry is copied to userland with 4 padding bytes
between cylinders and start fields uninitialized on 64-bit platforms.
It leads to leaking of contents of kernel stack memory.

Currently there is no memset() in real implementations of getgeo()
in drivers/block/, so it makes sense to have memset() in blkdev_ioctl().

Signed-off-by: Vasiliy Kulikov <segooon@gmail.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

parent 77304d2a

block/ioctl.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -242,6 +242,7 @@ int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
		* We need to set the startsect first, the driver may
		* want to override it.
		*/
		memset(&geo, 0, sizeof(geo));
		geo.start = get_start_sect(bdev);
		ret = disk->fops->getgeo(bdev, &geo);
		if (ret)