From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christian Borntraeger Subject: Re: [PATCH 0/9] mm: Hardened usercopy Date: Thu, 7 Jul 2016 09:30:07 +0200 Message-ID: <577E04FF.1090000@de.ibm.com> References: <1467843928-29351-1-git-send-email-keescook@chromium.org> Reply-To: kernel-hardening@lists.openwall.com Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Return-path: List-Post: List-Help: List-Unsubscribe: List-Subscribe: In-Reply-To: <1467843928-29351-1-git-send-email-keescook@chromium.org> To: Kees Cook , linux-kernel@vger.kernel.org Cc: Rik van Riel , Casey Schaufler , PaX Team , Brad Spengler , Russell King , Catalin Marinas , Will Deacon , Ard Biesheuvel , Benjamin Herrenschmidt , Michael Ellerman , Tony Luck , Fenghua Yu , "David S. Miller" , x86@kernel.org, Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , Andy Lutomirski , Borislav Petkov List-Id: linux-arch.vger.kernel.org On 07/07/2016 12:25 AM, Kees Cook wrote: > Hi, > > This is a start of the mainline port of PAX_USERCOPY[1]. After I started > writing tests (now in lkdtm in -next) for Casey's earlier port[2], I > kept tweaking things further and further until I ended up with a whole > new patch series. To that end, I took Rik's feedback and made a number > of other changes and clean-ups as well. > > Based on my understanding, PAX_USERCOPY was designed to catch a few > classes of flaws around the use of copy_to_user()/copy_from_user(). These > changes don't touch get_user() and put_user(), since these operate on > constant sized lengths, and tend to be much less vulnerable. There > are effectively three distinct protections in the whole series, > each of which I've given a separate CONFIG, though this patch set is > only the first of the three intended protections. (Generally speaking, > PAX_USERCOPY covers what I'm calling CONFIG_HARDENED_USERCOPY (this) and > CONFIG_HARDENED_USERCOPY_WHITELIST (future), and PAX_USERCOPY_SLABS covers > CONFIG_HARDENED_USERCOPY_SPLIT_KMALLOC (future).) > > This series, which adds CONFIG_HARDENED_USERCOPY, checks that objects > being copied to/from userspace meet certain criteria: > - if address is a heap object, the size must not exceed the object's > allocated size. (This will catch all kinds of heap overflow flaws.) > - if address range is in the current process stack, it must be within the > current stack frame (if such checking is possible) or at least entirely > within the current process's stack. (This could catch large lengths that > would have extended beyond the current process stack, or overflows if > their length extends back into the original stack.) > - if the address range is part of kernel data, rodata, or bss, allow it. > - if address range is page-allocated, that it doesn't span multiple > allocations. > - if address is within the kernel text, reject it. > - everything else is accepted > > The patches in the series are: > - The core copy_to/from_user() checks, without the slab object checks: > 1- mm: Hardened usercopy > - Per-arch enablement of the protection: > 2- x86/uaccess: Enable hardened usercopy > 3- ARM: uaccess: Enable hardened usercopy > 4- arm64/uaccess: Enable hardened usercopy > 5- ia64/uaccess: Enable hardened usercopy > 6- powerpc/uaccess: Enable hardened usercopy > 7- sparc/uaccess: Enable hardened usercopy Was there a reason why you did not change s390? From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:59396 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751375AbcGGHaR (ORCPT ); Thu, 7 Jul 2016 03:30:17 -0400 Received: from pps.filterd (m0098396.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.11/8.16.0.11) with SMTP id u677T8jA119560 for ; Thu, 7 Jul 2016 03:30:17 -0400 Received: from e06smtp17.uk.ibm.com (e06smtp17.uk.ibm.com [195.75.94.113]) by mx0a-001b2d01.pphosted.com with ESMTP id 2415xkqmea-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Thu, 07 Jul 2016 03:30:17 -0400 Received: from localhost by e06smtp17.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 7 Jul 2016 08:30:14 +0100 Subject: Re: [PATCH 0/9] mm: Hardened usercopy References: <1467843928-29351-1-git-send-email-keescook@chromium.org> From: Christian Borntraeger Date: Thu, 7 Jul 2016 09:30:07 +0200 MIME-Version: 1.0 In-Reply-To: <1467843928-29351-1-git-send-email-keescook@chromium.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Message-ID: <577E04FF.1090000@de.ibm.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Kees Cook , linux-kernel@vger.kernel.org Cc: Rik van Riel , Casey Schaufler , PaX Team , Brad Spengler , Russell King , Catalin Marinas , Will Deacon , Ard Biesheuvel , Benjamin Herrenschmidt , Michael Ellerman , Tony Luck , Fenghua Yu , "David S. Miller" , x86@kernel.org, Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , Andy Lutomirski , Borislav Petkov , Mathias Krause , Jan Kara , Vitaly Wool , Andrea Arcangeli , Dmitry Vyukov , Laura Abbott , linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, sparclinux@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, kernel-hardening@lists.openwall.com Message-ID: <20160707073007.q2DGw7Zxqg_nRLJMkyaYVCYEBwotFXx2CCFKvhvFQSg@z> On 07/07/2016 12:25 AM, Kees Cook wrote: > Hi, > > This is a start of the mainline port of PAX_USERCOPY[1]. After I started > writing tests (now in lkdtm in -next) for Casey's earlier port[2], I > kept tweaking things further and further until I ended up with a whole > new patch series. To that end, I took Rik's feedback and made a number > of other changes and clean-ups as well. > > Based on my understanding, PAX_USERCOPY was designed to catch a few > classes of flaws around the use of copy_to_user()/copy_from_user(). These > changes don't touch get_user() and put_user(), since these operate on > constant sized lengths, and tend to be much less vulnerable. There > are effectively three distinct protections in the whole series, > each of which I've given a separate CONFIG, though this patch set is > only the first of the three intended protections. (Generally speaking, > PAX_USERCOPY covers what I'm calling CONFIG_HARDENED_USERCOPY (this) and > CONFIG_HARDENED_USERCOPY_WHITELIST (future), and PAX_USERCOPY_SLABS covers > CONFIG_HARDENED_USERCOPY_SPLIT_KMALLOC (future).) > > This series, which adds CONFIG_HARDENED_USERCOPY, checks that objects > being copied to/from userspace meet certain criteria: > - if address is a heap object, the size must not exceed the object's > allocated size. (This will catch all kinds of heap overflow flaws.) > - if address range is in the current process stack, it must be within the > current stack frame (if such checking is possible) or at least entirely > within the current process's stack. (This could catch large lengths that > would have extended beyond the current process stack, or overflows if > their length extends back into the original stack.) > - if the address range is part of kernel data, rodata, or bss, allow it. > - if address range is page-allocated, that it doesn't span multiple > allocations. > - if address is within the kernel text, reject it. > - everything else is accepted > > The patches in the series are: > - The core copy_to/from_user() checks, without the slab object checks: > 1- mm: Hardened usercopy > - Per-arch enablement of the protection: > 2- x86/uaccess: Enable hardened usercopy > 3- ARM: uaccess: Enable hardened usercopy > 4- arm64/uaccess: Enable hardened usercopy > 5- ia64/uaccess: Enable hardened usercopy > 6- powerpc/uaccess: Enable hardened usercopy > 7- sparc/uaccess: Enable hardened usercopy Was there a reason why you did not change s390?