From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <1427981431.22575.21.camel@opteya.com> From: Yann Droneaud To: Shachar Raindel , Haggai Eran , Sagi Grimberg Cc: "oss-security@lists.openwall.com" , " (linux-rdma@vger.kernel.org)" , "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" Date: Thu, 02 Apr 2015 15:30:31 +0200 In-Reply-To: References: <1427969085.17020.5.camel@opteya.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: Re: CVE-2014-8159 kernel: infiniband: uverbs: unprotected physical memory access Sender: linux-kernel-owner@vger.kernel.org List-ID: Hi, Le jeudi 02 avril 2015 à 10:52 +0000, Shachar Raindel a écrit : > > -----Original Message----- > > From: Yann Droneaud [mailto:ydroneaud@opteya.com] > > Sent: Thursday, April 02, 2015 1:05 PM > > Le mercredi 18 mars 2015 à 17:39 +0000, Shachar Raindel a écrit : > > > + /* > > > + * If the combination of the addr and size requested for this > > memory > > > + * region causes an integer overflow, return error. > > > + */ > > > + if ((PAGE_ALIGN(addr + size) <= size) || > > > + (PAGE_ALIGN(addr + size) <= addr)) > > > + return ERR_PTR(-EINVAL); > > > + > > > > Can access_ok() be used here ? > > > > if (!access_ok(writable ? VERIFY_WRITE : VERIFY_READ, > > addr, size)) > > return ERR_PTR(-EINVAL); > > > > No, this will break the current ODP semantics. > > ODP allows the user to register memory that is not accessible yet. > This is a critical design feature, as it allows avoiding holding > a registration cache. Adding this check will break the behavior, > forcing memory to be all accessible when registering an ODP MR. > Where's the check for the range being in userspace memory space, especially for the ODP case ? For non ODP case (eg. plain old behavior), does get_user_pages() ensure the requested pages fit in userspace region on all architectures ? I think so. In ODP case, I'm not sure such check is ever done ? (Aside, does it take special mesure to protect shared mapping from being read and/or *written* ?) Regards. -- Yann Droneaud OPTEYA