Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753273AbeAFKE5 (ORCPT + 1 other); Sat, 6 Jan 2018 05:04:57 -0500 Received: from mail-lf0-f68.google.com ([209.85.215.68]:37913 "EHLO mail-lf0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752845AbeAFKEy (ORCPT ); Sat, 6 Jan 2018 05:04:54 -0500 X-Google-Smtp-Source: ACJfBotz63VftFgGPJ+rYsjcwn1nAoTg5os8Cshd6oxSYFAD8P5WiKW7fqMDZTQc1EbI+rguVwdMlQ== Subject: Re: [PATCH 14/18] ipv4: prevent bounds-check bypass via speculative execution To: Dan Williams , linux-kernel@vger.kernel.org Cc: linux-arch@vger.kernel.org, Hideaki YOSHIFUJI , netdev@vger.kernel.org, peterz@infradead.org, gregkh@linuxfoundation.org, Alexey Kuznetsov , tglx@linutronix.de, torvalds@linux-foundation.org, "David S. Miller" , Elena Reshetova , alan@linux.intel.com References: <151520099201.32271.4677179499894422956.stgit@dwillia2-desk3.amr.corp.intel.com> <151520107001.32271.12149241186695668220.stgit@dwillia2-desk3.amr.corp.intel.com> From: Sergei Shtylyov Message-ID: Date: Sat, 6 Jan 2018 13:04:52 +0300 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.5.2 MIME-Version: 1.0 In-Reply-To: <151520107001.32271.12149241186695668220.stgit@dwillia2-desk3.amr.corp.intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: On 1/6/2018 4:11 AM, Dan Williams wrote: > Static analysis reports that 'offset' may be a user controlled value > that is used as a data dependency reading from a raw_frag_vec buffer. > In order to avoid potential leaks of kernel memory values, block > speculative execution of the instruction stream that could issue further > reads based on an invalid '*(rfv->c + offset)' value. > > Based on an original patch by Elena Reshetova. > > Cc: "David S. Miller" > Cc: Alexey Kuznetsov > Cc: Hideaki YOSHIFUJI > Cc: netdev@vger.kernel.org > Signed-off-by: Elena Reshetova > Signed-off-by: Dan Williams > --- > net/ipv4/raw.c | 9 +++++---- > 1 file changed, 5 insertions(+), 4 deletions(-) > > diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c > index 125c1eab3eaa..f72b20131a15 100644 > --- a/net/ipv4/raw.c > +++ b/net/ipv4/raw.c [...] > @@ -472,17 +473,17 @@ static int raw_getfrag(void *from, char *to, int offset, int len, int odd, > struct sk_buff *skb) > { > struct raw_frag_vec *rfv = from; > + char *rfv_buf; > > - if (offset < rfv->hlen) { > + if ((rfv_buf = nospec_array_ptr(rfv->hdr.c, offset, rfv->hlen))) { And here... [...] MBR, Sergei