Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753092AbdFSTJY (ORCPT + 2 others); Mon, 19 Jun 2017 15:09:24 -0400 Received: from wtarreau.pck.nerim.net ([62.212.114.60]:52388 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753461AbdFSSgv (ORCPT ); Mon, 19 Jun 2017 14:36:51 -0400 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, linux@roeck-us.net Cc: Eric Dumazet , Willy Tarreau Subject: [PATCH 3.10 197/268] ipv4: provide stronger user input validation in nl_fib_input() Date: Mon, 19 Jun 2017 20:31:36 +0200 Message-Id: <1497897167-14556-198-git-send-email-w@1wt.eu> X-Mailer: git-send-email 2.8.0.rc2.1.gbe9624a In-Reply-To: <1497897167-14556-1-git-send-email-w@1wt.eu> References: <1497897167-14556-1-git-send-email-w@1wt.eu> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: From: Eric Dumazet commit c64c0b3cac4c5b8cb093727d2c19743ea3965c0b upstream. Alexander reported a KMSAN splat caused by reads of uninitialized field (tb_id_in) from user provided struct fib_result_nl It turns out nl_fib_input() sanity tests on user input is a bit wrong : User can pretend nlh->nlmsg_len is big enough, but provide at sendmsg() time a too small buffer. Reported-by: Alexander Potapenko Signed-off-by: Eric Dumazet Signed-off-by: Willy Tarreau --- net/ipv4/fib_frontend.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c index 4556cd2..017b479 100644 --- a/net/ipv4/fib_frontend.c +++ b/net/ipv4/fib_frontend.c @@ -957,7 +957,8 @@ static void nl_fib_input(struct sk_buff *skb) net = sock_net(skb->sk); nlh = nlmsg_hdr(skb); - if (skb->len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len || + if (skb->len < nlmsg_total_size(sizeof(*frn)) || + skb->len < nlh->nlmsg_len || nlmsg_len(nlh) < sizeof(*frn)) return; -- 2.8.0.rc2.1.gbe9624a