From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f67.google.com ([74.125.82.67]:55585 "EHLO mail-wm0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751534AbeFEHAB (ORCPT ); Tue, 5 Jun 2018 03:00:01 -0400 Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 11.3 \(3445.6.18\)) Subject: Re: [PATCH] ksys_mount: check for permissions before resource allocation From: Ilya Matveychikov In-Reply-To: Date: Tue, 5 Jun 2018 10:59:51 +0400 Cc: Alexander Viro , linux-fsdevel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Message-Id: References: To: linux-kernel@vger.kernel.org Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Just CC=E2=80=99ed to some of maintainers. $ perl scripts/get_maintainer.pl = fs/0001-ksys_mount-check-for-permissions-before-resource-all.patch Alexander Viro (maintainer:FILESYSTEMS (VFS = and infrastructure)) linux-fsdevel@vger.kernel.org (open list:FILESYSTEMS (VFS and = infrastructure)) linux-kernel@vger.kernel.org (open list) > On Jun 5, 2018, at 6:00 AM, Ilya Matveychikov = wrote: >=20 > Early check for mount permissions prevents possible allocation of 3 > pages from kmalloc() pool by unpriveledged user which can be used for > spraying the kernel heap. >=20 > Signed-off-by: Ilya V. Matveychikov > --- > fs/namespace.c | 3 +++ > 1 file changed, 3 insertions(+) >=20 > diff --git a/fs/namespace.c b/fs/namespace.c > index 5f75969adff1..1ef8feb2de2a 100644 > --- a/fs/namespace.c > +++ b/fs/namespace.c > @@ -3046,6 +3046,9 @@ int ksys_mount(char __user *dev_name, char = __user *dir_name, char __user *type, > char *kernel_dev; > void *options; >=20 > + if (!may_mount()) > + return -EPERM; > + > kernel_type =3D copy_mount_string(type); > ret =3D PTR_ERR(kernel_type); > if (IS_ERR(kernel_type)) > -- > 2.17.0 >=20