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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 B0D73C47082 for ; Wed, 26 May 2021 16:49:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8C6CF6113D for ; Wed, 26 May 2021 16:49:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233459AbhEZQvM (ORCPT ); Wed, 26 May 2021 12:51:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37318 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233324AbhEZQvJ (ORCPT ); Wed, 26 May 2021 12:51:09 -0400 Received: from mail-qk1-x731.google.com (mail-qk1-x731.google.com [IPv6:2607:f8b0:4864:20::731]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4052CC061756 for ; Wed, 26 May 2021 09:49:37 -0700 (PDT) Received: by mail-qk1-x731.google.com with SMTP id h20so1623711qko.11 for ; Wed, 26 May 2021 09:49:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=C+1GNfV1+wpE6FJNpUedBO+JQbCvS5qLbCtmsgVd4dM=; b=EDhzTJ5PmnLhjw6osyX4ttpz30oEIlfRO7d3u6PcYUemIcz6UCFFzp3RKbXcij1Wzi 2d8Oc3zOVEhMZhcfu8hnUShBsh3sxbl0EKkbuRPPbKs2pG+BWjDLisUNMQ6W/Ts/cDed SG/pcN016zS0iBksnGHZMZ4HloTZG6BwUQUpxL2xA0WKfbh+m0fPXzP6t5noeye+Cmuw 2hm/orXeB0fOx6twPm2DnQyhVnsCEE0S9cRtrRSv+ZNTMY4l+m5sgxpiZrhetkFKeYGB 1q9WcHJWgXFwNh4g70I08kq92mPyetXOcmUPNvwC5cMPuKxgRYvTgOVv/hSPTUZ97k00 WK9Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=C+1GNfV1+wpE6FJNpUedBO+JQbCvS5qLbCtmsgVd4dM=; b=Bb7vIzm6OOsIJHl5H99gclsK4IXLjWh/GFoNZQMexQLJgZiWc2iIq9j3XbA3CFMxWX XN59T3ZT93NfKnBXmPKQpLTPtEbhXoZ5XDQaAgULpAfoL5T+kNcKnq0d/6ARJRFmkjIu 4+dW7phmZEnSM87fY+CX4BSWDbKz3P2QT0A/WmrWQLph7TARHN1VCKkjtkVBT4EZJXtg cpDIqNnUOMVas86oNpWiK4S16Q+Y/VqenV2bfXhD2tssaZIaJvt6jVxicanN0Wz8fK49 gvTXH6qdzFlcwwKorGEBplumr0NJ+3HaJHN4sanWCliOkDKhCB0+7/xxL3BiUFdF8MeG /FoQ== X-Gm-Message-State: AOAM530u9aYnClmFMOpVuPENy7NeCnJboe/WDl4t5+jbBZklWcM3pKeC N7ye+zawqAkvoy55ikGqcaR3xA== X-Google-Smtp-Source: ABdhPJy3JhTUaYioJDxIsNhfjw5ZVnKtNIvVYD9hwieO3TzuuAH5M4nce2RL8cr4SoIlIvIicyE0Dw== X-Received: by 2002:ae9:e41a:: with SMTP id q26mr42764502qkc.78.1622047776397; Wed, 26 May 2021 09:49:36 -0700 (PDT) Received: from ziepe.ca ([206.223.160.26]) by smtp.gmail.com with ESMTPSA id d11sm1912764qkj.24.2021.05.26.09.49.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 26 May 2021 09:49:35 -0700 (PDT) Received: from jgg by mlx with local (Exim 4.94) (envelope-from ) id 1llwis-00FEKy-GU; Wed, 26 May 2021 13:49:34 -0300 Date: Wed, 26 May 2021 13:49:34 -0300 From: Jason Gunthorpe To: Colin King Cc: =?utf-8?B?SsOpcsO0bWU=?= Glisse , Alistair Popple , Ralph Campbell , Stephen Rothwell , Andrew Morton , linux-mm@kvack.org, kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH][next] mm: selftests: fix potential integer overflow on shift of a int Message-ID: <20210526164934.GD1096940@ziepe.ca> References: <20210526150947.3751728-1-colin.king@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210526150947.3751728-1-colin.king@canonical.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 26, 2021 at 04:09:47PM +0100, Colin King wrote: > From: Colin Ian King > > The left shift of the int mapped is evaluated using 32 bit arithmetic > and then assigned to an unsigned long. In the case where mapped is > 0x80000 when PAGE_SHIFT is 12 will lead to the upper bits being > sign extended in the unsigned long. Larger values can lead to an > int overflow. Avoid this by casting mapped to unsigned long before > shifting. > > Addresses-Coverity: ("Uninitentional integer overflow") > Fixes: 8b2a105c3794 ("mm: selftests for exclusive device memory") > Signed-off-by: Colin Ian King > lib/test_hmm.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/lib/test_hmm.c b/lib/test_hmm.c > index 74d69f87691e..b54657701b3a 100644 > +++ b/lib/test_hmm.c > @@ -749,7 +749,7 @@ static int dmirror_exclusive(struct dmirror *dmirror, > } > } > > - if (addr + (mapped << PAGE_SHIFT) < next) { > + if (addr + ((unsigned int)mapped << PAGE_SHIFT) < next) { Just fix the type for mapped. It started out as an unsigned long in dmirror_atomic_map() and wrongly became an int here Jason