cdrom: Fix info leak/OOB read in cdrom_ioctl_drive_status

Scott Bauer · axboe · commit 8f3fafc9c2f0 · 2018-08-29T08:09:20.000-06:00
Like d88b6d0: "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>
diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c
@@ -2546,7 +2546,7 @@ 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);
 }

Original file line number	Diff line number	Diff line change
`@@ -2546,7 +2546,7 @@ static int cdrom_ioctl_drive_status(struct cdrom_device_info *cdi,`
`2546`	`2546`	`if (!CDROM_CAN(CDC_SELECT_DISC) \|\|`
`2547`	`2547`	`(arg == CDSL_CURRENT \|\| arg == CDSL_NONE))`
`2548`	`2548`	`return cdi->ops->drive_status(cdi, CDSL_CURRENT);`
`2549`		`- if (((int)arg >= cdi->capacity))`
	`2549`	`+ if (arg >= cdi->capacity)`
`2550`	`2550`	`return -EINVAL;`
`2551`	`2551`	`return cdrom_slot_status(cdi, arg);`
`2552`	`2552`	`}`