cdrom: Fix spectre-v1 gadget

This patch fixes a spectre-v1 gadget in cdrom.
The gadget could be triggered by speculatively
bypassing the cdi->capacity check.

Signed-off-by: Jordy Zomer <jordyzomer@google.com>
Link: https://lore.kernel.org/all/20230612110040.849318-2-jordyzomer@google.com
Reviewed-by: Phillip Potter <phil@philpotter.co.uk>
Link: https://lore.kernel.org/all/ZI1+1OG9Ut1MqsUC@equinox
Signed-off-by: Phillip Potter <phil@philpotter.co.uk>
Link: https://lore.kernel.org/r/20230617113828.1230-2-phil@philpotter.co.uk
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jordy Zomer 2023-06-17 12:38:28 +01:00 committed by Jens Axboe
parent 017fb83ee0
commit 8270cb10c0

View File

@ -264,6 +264,7 @@
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/nospec.h>
#include <linux/slab.h>
#include <linux/cdrom.h>
#include <linux/sysctl.h>
@ -2311,6 +2312,9 @@ static int cdrom_ioctl_media_changed(struct cdrom_device_info *cdi,
if (arg >= cdi->capacity)
return -EINVAL;
/* Prevent arg from speculatively bypassing the length check */
barrier_nospec();
info = kmalloc(sizeof(*info), GFP_KERNEL);
if (!info)
return -ENOMEM;