From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexei Starovoitov Subject: Re: [PATCH] net: filter: make JITs zero A for SKF_AD_ALU_XOR_X Date: Tue, 5 Jan 2016 09:43:10 -0800 Message-ID: <20160105174309.GA83548@ast-mbp.thefacebook.com> References: <1452007387-626-1-git-send-email-rabin@rab.in> <568BF11F.1060507@iogearbox.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Rabin Vincent , davem@davemloft.net, netdev@vger.kernel.org, ast@kernel.org, linux-arm-kernel@lists.infradead.org, linux-mips@linux-mips.org, linuxppc-dev@lists.ozlabs.org, sparclinux@vger.kernel.org, linux-kernel@vger.kernel.org To: Daniel Borkmann Return-path: Received: from mail-pa0-f50.google.com ([209.85.220.50]:32883 "EHLO mail-pa0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752073AbcAERnP (ORCPT ); Tue, 5 Jan 2016 12:43:15 -0500 Content-Disposition: inline In-Reply-To: <568BF11F.1060507@iogearbox.net> Sender: netdev-owner@vger.kernel.org List-ID: On Tue, Jan 05, 2016 at 05:36:47PM +0100, Daniel Borkmann wrote: > On 01/05/2016 04:23 PM, Rabin Vincent wrote: > >The SKF_AD_ALU_XOR_X ancillary is not like the other ancillary data > >instructions since it XORs A with X while all the others replace A with > >some loaded value. All the BPF JITs fail to clear A if this is used as > >the first instruction in a filter. This was found using american fuzzy > >lop. > > > >Add a helper to determine if A needs to be cleared given the first > >instruction in a filter, and use this in the JITs. Except for ARM, the > >rest have only been compile-tested. > > > >Fixes: 3480593131e0 ("net: filter: get rid of BPF_S_* enum") > >Signed-off-by: Rabin Vincent > > Excellent catch, thanks a lot! The fix looks good to me and should > go to -net tree. > > Acked-by: Daniel Borkmann good catch indeed. Classic bpf jits didn't have much love. Great to see this work. Acked-by: Alexei Starovoitov