Commit 8270cb10 authored Jun 17, 2023 by Jordy Zomer Committed by Jens Axboe Jun 22, 2023

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>

parent 017fb83e

drivers/cdrom/cdrom.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -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;