Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756236Ab2BQBeD (ORCPT ); Thu, 16 Feb 2012 20:34:03 -0500 Received: from terminus.zytor.com ([198.137.202.10]:36203 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755320Ab2BQBeA (ORCPT ); Thu, 16 Feb 2012 20:34:00 -0500 Message-ID: <4F3DAE5D.3080000@zytor.com> Date: Thu, 16 Feb 2012 17:33:17 -0800 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:10.0) Gecko/20120131 Thunderbird/10.0 MIME-Version: 1.0 To: Indan Zupancic CC: Will Drewry , linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linux-doc@vger.kernel.org, kernel-hardening@lists.openwall.com, netdev@vger.kernel.org, x86@kernel.org, arnd@arndb.de, davem@davemloft.net, mingo@redhat.com, oleg@redhat.com, peterz@infradead.org, rdunlap@xenotime.net, mcgrathr@chromium.org, tglx@linutronix.de, luto@mit.edu, eparis@redhat.com, serge.hallyn@canonical.com, djm@mindrot.org, scarybeasts@gmail.com, pmoore@redhat.com, akpm@linux-foundation.org, corbet@lwn.net, eric.dumazet@gmail.com, markus@chromium.org, keescook@chromium.org Subject: Re: [PATCH v8 3/8] seccomp: add system call filtering using BPF References: <1329422549-16407-1-git-send-email-wad@chromium.org> <1329422549-16407-3-git-send-email-wad@chromium.org> <4F3D61CB.2000301@zytor.com> <4F3D7250.6040504@zytor.com> <501858544d264abc6526f2b25a224f2b.squirrel@webmail.greenhost.nl> In-Reply-To: <501858544d264abc6526f2b25a224f2b.squirrel@webmail.greenhost.nl> X-Enigmail-Version: 1.3.5 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1352 Lines: 41 On 02/16/2012 04:48 PM, Indan Zupancic wrote: > On Thu, February 16, 2012 22:17, H. Peter Anvin wrote: > > I would go for something like: > > struct seccomp_data { > int nr; > __u32 arg_low[6]; > __u32 arg_high[6]; > __u32 instruction_pointer_low; > __u32 instruction_pointer_high; > __u32 __reserved[3]; > }; > Uh, that is the absolutely WORST way to do it - not only are you creating two fields, they're not even adjacent. > (Not sure what use the IP is because that doesn't tell anything about how > the system call instruction was reached.) > > The only way to avoid splitting args is to add 64-bit support to BPF. > That is probably the best way forwards, but would require breaking the > BPF ABI by either adding a 64-bit version directly or adding extra > instructions. Or the compiler or whatever generates the BPF code just is going to have to generate two instructions -- just like we always have to handle [u]int64_t on 32-bit platforms. There is no difference here. -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/