diff mbox

cdrom: information leak in cdrom_ioctl_media_changed()

Message ID 20180418095130.GA26904@mwanda (mailing list archive)
State New, archived
Headers show

Commit Message

Dan Carpenter April 18, 2018, 9:51 a.m. UTC 
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.

Cc: stable@vger.kernel.org
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

Comments

Christoph Hellwig April 18, 2018, 10:35 a.m. UTC | #1 
On Wed, Apr 18, 2018 at 12:51:31PM +0300, Dan Carpenter wrote:
> 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.

Looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>
Jens Axboe April 18, 2018, 2:21 p.m. UTC | #2 
On 4/18/18 3:51 AM, Dan Carpenter wrote:
> 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.

Thanks Dan, applied.
diff mbox

Patch

diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c
index 8327478effd0..bfc566d3f31a 100644
--- a/drivers/cdrom/cdrom.c
+++ b/drivers/cdrom/cdrom.c
@@ -2371,7 +2371,7 @@  static int cdrom_ioctl_media_changed(struct cdrom_device_info *cdi,
 	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);