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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 C08C4C433EF for ; Mon, 18 Jun 2018 08:37:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7D1EC20864 for ; Mon, 18 Jun 2018 08:37:57 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7D1EC20864 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 S968148AbeFRIhz (ORCPT ); Mon, 18 Jun 2018 04:37:55 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:36792 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S968119AbeFRIhv (ORCPT ); Mon, 18 Jun 2018 04:37:51 -0400 Received: from localhost (LFbn-1-12247-202.w90-92.abo.wanadoo.fr [90.92.61.202]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id ED250CBA; Mon, 18 Jun 2018 08:37:50 +0000 (UTC) From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dan Carpenter , Daniel Vetter , Sasha Levin Subject: [PATCH 4.14 178/189] drm/dumb-buffers: Integer overflow in drm_mode_create_ioctl() Date: Mon, 18 Jun 2018 10:14:34 +0200 Message-Id: <20180618081216.372195590@linuxfoundation.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20180618081209.254234434@linuxfoundation.org> References: <20180618081209.254234434@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: Dan Carpenter [ Upstream commit 2b6207291b7b277a5df9d1aab44b56815a292dba ] There is a comment here which says that DIV_ROUND_UP() and that's where the problem comes from. Say you pick: args->bpp = UINT_MAX - 7; args->width = 4; args->height = 1; The integer overflow in DIV_ROUND_UP() means "cpp" is UINT_MAX / 8 and because of how we picked args->width that means cpp < UINT_MAX / 4. I've fixed it by preventing the integer overflow in DIV_ROUND_UP(). I removed the check for !cpp because it's not possible after this change. I also changed all the 0xffffffffU references to U32_MAX. Signed-off-by: Dan Carpenter Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20180516140026.GA19340@mwanda Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/drm_dumb_buffers.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) --- a/drivers/gpu/drm/drm_dumb_buffers.c +++ b/drivers/gpu/drm/drm_dumb_buffers.c @@ -65,12 +65,13 @@ int drm_mode_create_dumb_ioctl(struct dr return -EINVAL; /* overflow checks for 32bit size calculations */ - /* NOTE: DIV_ROUND_UP() can overflow */ + if (args->bpp > U32_MAX - 8) + return -EINVAL; cpp = DIV_ROUND_UP(args->bpp, 8); - if (!cpp || cpp > 0xffffffffU / args->width) + if (cpp > U32_MAX / args->width) return -EINVAL; stride = cpp * args->width; - if (args->height > 0xffffffffU / stride) + if (args->height > U32_MAX / stride) return -EINVAL; /* test for wrap-around */