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[148.163.158.5]) by mx.google.com with ESMTPS id w7si1738899wjf.146.2016.07.07.00.30.24 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 07 Jul 2016 00:30:24 -0700 (PDT) Received: from pps.filterd (m0098413.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.11/8.16.0.11) with SMTP id u677TAI0134447 for ; Thu, 7 Jul 2016 03:30:23 -0400 Received: from e06smtp12.uk.ibm.com (e06smtp12.uk.ibm.com [195.75.94.108]) by mx0b-001b2d01.pphosted.com with ESMTP id 2415xmyb50-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Thu, 07 Jul 2016 03:30:22 -0400 Received: from localhost by e06smtp12.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 7 Jul 2016 08:30:20 +0100 Received: from b06cxnps3075.portsmouth.uk.ibm.com (d06relay10.portsmouth.uk.ibm.com [9.149.109.195]) by d06dlp01.portsmouth.uk.ibm.com (Postfix) with ESMTP id 930B617D8069 for ; Thu, 7 Jul 2016 08:31:34 +0100 (BST) Received: from d06av08.portsmouth.uk.ibm.com (d06av08.portsmouth.uk.ibm.com [9.149.37.249]) by b06cxnps3075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id u677UAnU9372116 for ; Thu, 7 Jul 2016 07:30:10 GMT Received: from d06av08.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av08.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id u677U8BM028031 for ; Thu, 7 Jul 2016 01:30:10 -0600 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: owner-linux-mm@kvack.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 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? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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