From 9de4ee40547fd315d4a0ed1dd15a2fa3559ad707 Mon Sep 17 00:00:00 2001
From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Wed, 18 Apr 2018 12:51:31 +0300
Subject: [PATCH] cdrom: information leak in cdrom_ioctl_media_changed()
Git-commit: 9de4ee40547fd315d4a0ed1dd15a2fa3559ad707
Patch-mainline: v4.17-rc3
References: bsc#1051510,bsc#1092903,CVE-2018-10940

This cast is wrong.  "cdi->capacity" is an int and "arg" is an unsigned
long.  The way the check is written now, if one of the high 32 bits is
set then we could read outside the info->slots[] array.

This bug is pretty old and it predates git.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Takashi Iwai <tiwai@suse.de>
Acked-by: Martin Wilck <mwilck@suse.com>

---
 drivers/cdrom/cdrom.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/cdrom/cdrom.c
+++ b/drivers/cdrom/cdrom.c
@@ -2357,7 +2357,7 @@ static int cdrom_ioctl_media_changed(str
 	if (!CDROM_CAN(CDC_SELECT_DISC) || arg == CDSL_CURRENT)
 		return media_changed(cdi, 1);
 
-	if ((unsigned int)arg >= cdi->capacity)
+	if (arg >= cdi->capacity)
 		return -EINVAL;
 
 	info = kmalloc(sizeof(*info), GFP_KERNEL);