From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Borkmann Subject: Re: [PATCH net-next] x86: bpf_jit_comp: secure bpf jit against spraying attacks Date: Sun, 19 May 2013 19:02:46 +0200 Message-ID: <519905B6.3080101@redhat.com> References: <1368844623.3301.142.camel@edumazet-glaptop> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: David Miller , netdev , "H. Peter Anvin" , "linux-kernel@vger.kernel.org" To: Eric Dumazet Return-path: Received: from mx1.redhat.com ([209.132.183.28]:46957 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751950Ab3ESRDA (ORCPT ); Sun, 19 May 2013 13:03:00 -0400 In-Reply-To: <1368844623.3301.142.camel@edumazet-glaptop> Sender: netdev-owner@vger.kernel.org List-ID: On 05/18/2013 04:37 AM, Eric Dumazet wrote: > From: Eric Dumazet > > hpa bringed into my attention some security related issues > with BPF JIT on x86. > > This patch makes sure the bpf generated code is marked read only, > as other kernel text sections. > > It also splits the unused space (we vmalloc() and only use a fraction of > the page) in two parts, so that the generated bpf code not starts at a > known offset in the page, but a pseudo random one. > > Refs: > http://mainisusuallyafunction.blogspot.com/2012/11/attacking-hardened-linux-systems-with.html > > Reported-by: H. Peter Anvin > Signed-off-by: Eric Dumazet Great work ! Probably other archs could later on follow-up with setting to read-only, too. Reviewed-by: Daniel Borkmann