Commit 4edbe1d7 authored by Mikulas Patocka's avatar Mikulas Patocka Committed by Mike Snitzer
Browse files

dm ioctl: fix out of bounds array access when no devices 



If there are not any dm devices, we need to zero the "dev" argument in
the first structure dm_name_list. However, this can cause out of
bounds write, because the "needed" variable is zero and len may be
less than eight.

Fix this bug by reporting DM_BUFFER_FULL_FLAG if the result buffer is
too small to hold the "nl->dev" value.

Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
Reported-by: default avatarDan Carpenter <dan.carpenter@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent 5424a0b8

drivers/md/dm-ioctl.c

+1 −1
Original line number Diff line number Diff line
@@ -529,7 +529,7 @@ static int list_devices(struct file *filp, struct dm_ioctl *param, size_t param_ 
	 * Grab our output buffer.

	 */

	nl = orig_nl = get_result_buffer(param, param_size, &len);

	if (len < needed) {

	if (len < needed || len < sizeof(nl->dev)) {

		param->flags |= DM_BUFFER_FULL_FLAG;

		goto out;

	}