From: Scott Bauer <scott.bauer@intel.com>
Date: Wed, 3 Oct 2018 06:29:00 +0000 (+0200)
Subject: cdrom: Fix info leak/OOB read in cdrom_ioctl_drive_status
X-Git-Tag: Ubuntu-4.15.0-39.42~43
X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;ds=sidebyside;h=00ab3ffb35c4472bc415dc90fc3a646c2b40630d;p=mirror_ubuntu-bionic-kernel.git

cdrom: Fix info leak/OOB read in cdrom_ioctl_drive_status

CVE-2018-16658

Like d88b6d04: "cdrom: information leak in cdrom_ioctl_media_changed()"

There is another cast from unsigned long to int which causes
a bounds check to fail with specially crafted input. The value is
then used as an index in the slot array in cdrom_slot_status().

Signed-off-by: Scott Bauer <scott.bauer@intel.com>
Signed-off-by: Scott Bauer <sbauer@plzdonthack.me>
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
(cherry picked from commit 8f3fafc9c2f0ece10832c25f7ffcb07c97a32ad4)
Signed-off-by: Po-Hsu Lin <po-hsu.lin@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
---

diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c
index cbee2e742795..f0534a4f00d0 100644
--- a/drivers/cdrom/cdrom.c
+++ b/drivers/cdrom/cdrom.c
@@ -2542,7 +2542,7 @@ static int cdrom_ioctl_drive_status(struct cdrom_device_info *cdi,
 	if (!CDROM_CAN(CDC_SELECT_DISC) ||
 	    (arg == CDSL_CURRENT || arg == CDSL_NONE))
 		return cdi->ops->drive_status(cdi, CDSL_CURRENT);
-	if (((int)arg >= cdi->capacity))
+	if (arg >= cdi->capacity)
 		return -EINVAL;
 	return cdrom_slot_status(cdi, arg);
 }