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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS 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 9939BC43387 for ; Thu, 17 Jan 2019 19:47:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7471820855 for ; Thu, 17 Jan 2019 19:47:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729066AbfAQTrz (ORCPT ); Thu, 17 Jan 2019 14:47:55 -0500 Received: from shards.monkeyblade.net ([23.128.96.9]:59480 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728776AbfAQTry (ORCPT ); Thu, 17 Jan 2019 14:47:54 -0500 Received: from localhost (unknown [IPv6:2601:601:9f80:35cd::bf5]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id D494C14B9556D; Thu, 17 Jan 2019 11:47:53 -0800 (PST) Date: Thu, 17 Jan 2019 11:47:53 -0800 (PST) Message-Id: <20190117.114753.495905826813982221.davem@davemloft.net> To: colin.king@canonical.com Cc: 3chas3@gmail.com, linux-atm-general@lists.sourceforge.net, netdev@vger.kernel.org, kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] atm: he: fix sign-extension overflow on large shift From: David Miller In-Reply-To: <20190115180338.32357-1-colin.king@canonical.com> References: <20190115180338.32357-1-colin.king@canonical.com> X-Mailer: Mew version 6.8 on Emacs 26.1 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Thu, 17 Jan 2019 11:47:54 -0800 (PST) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Colin King Date: Tue, 15 Jan 2019 18:03:38 +0000 > From: Colin Ian King > > Shifting the 1 by exp by an int can lead to sign-extension overlow when > exp is 31 since 1 is an signed int and sign-extending this result to an > unsigned long long will set the upper 32 bits. Fix this by shifting an > unsigned long. > > Detected by cppcheck: > (warning) Shifting signed 32-bit value by 31 bits is undefined behaviour > > Signed-off-by: Colin Ian King Applied.