From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7BF20C28CF6 for ; Wed, 1 Aug 2018 17:23:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2765520844 for ; Wed, 1 Aug 2018 17:23:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2765520844 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390454AbeHATKi (ORCPT ); Wed, 1 Aug 2018 15:10:38 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:51044 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390435AbeHATKh (ORCPT ); Wed, 1 Aug 2018 15:10:37 -0400 Received: from localhost (D57E6652.static.ziggozakelijk.nl [213.126.102.82]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id 98FDDD27; Wed, 1 Aug 2018 17:23:55 +0000 (UTC) From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, kernel test robot , Dmitry Safonov , "David S. Miller" Subject: [PATCH 4.14 241/246] netlink: Dont shift with UB on nlk->ngroups Date: Wed, 1 Aug 2018 18:52:31 +0200 Message-Id: <20180801165023.293235855@linuxfoundation.org> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20180801165011.700991984@linuxfoundation.org> References: <20180801165011.700991984@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dmitry Safonov [ Upstream commit 61f4b23769f0cc72ae62c9a81cf08f0397d40da8 ] On i386 nlk->ngroups might be 32 or 0. Which leads to UB, resulting in hang during boot. Check for 0 ngroups and use (unsigned long long) as a type to shift. Fixes: 7acf9d4237c4 ("netlink: Do not subscribe to non-existent groups"). Reported-by: kernel test robot Signed-off-by: Dmitry Safonov Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/netlink/af_netlink.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -976,7 +976,11 @@ static int netlink_bind(struct socket *s if (err) return err; } - groups &= (1UL << nlk->ngroups) - 1; + + if (nlk->ngroups == 0) + groups = 0; + else + groups &= (1ULL << nlk->ngroups) - 1; bound = nlk->bound; if (bound) {