From patchwork Thu Aug 28 13:50:01 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Herrmann X-Patchwork-Id: 4804771 Return-Path: X-Original-To: patchwork-dri-devel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id C57629F38C for ; Thu, 28 Aug 2014 13:50:30 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 9ED3620155 for ; Thu, 28 Aug 2014 13:50:29 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) by mail.kernel.org (Postfix) with ESMTP id 894602011D for ; Thu, 28 Aug 2014 13:50:28 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id B7D296E257; Thu, 28 Aug 2014 06:50:26 -0700 (PDT) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from mail-wg0-f41.google.com (mail-wg0-f41.google.com [74.125.82.41]) by gabe.freedesktop.org (Postfix) with ESMTP id E57486E257 for ; Thu, 28 Aug 2014 06:50:24 -0700 (PDT) Received: by mail-wg0-f41.google.com with SMTP id l18so761784wgh.0 for ; Thu, 28 Aug 2014 06:50:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:cc:subject:date:message-id; bh=2/kn+9TilE7Q7Lp4UKnRv2fDRv+ScATSHTgY5T9yziE=; b=Nf8iajao+wv0BhVCX8kKzj+WD7N4Mgf+2+aAYwj4AiJaOWOPmYVYl5SWJArixqmT09 kiT9AKiPmnmTco6IKDjTe8xwNih0AoAuJkU+Kfym5VVtvhUsXp6Dzz0HwEmQvkzvA7Kg 3uUG2EWvu8igaeEBml7/veFXNOXGABHSBZg7VVXJuNMIHUmdw42y7ccJsHNomalxtGfi Xe67u00Bga2w+2Qu2+MOqmQHEpdOELftyP10TqYMgNAEt/MyMeVz4aO/9iDnDsNQ93Hz usKthZ6UaFu3iZywwKKFaDUWAPcW5eQfRQMznFfAdPz+iaQfEe7V0hRXmCT/4VHeM/nG v0Tg== X-Received: by 10.180.104.163 with SMTP id gf3mr37167940wib.24.1409233821257; Thu, 28 Aug 2014 06:50:21 -0700 (PDT) Received: from david-tp.localdomain (stgt-5f7172a4.pool.mediaWays.net. [95.113.114.164]) by mx.google.com with ESMTPSA id ew1sm10105947wjb.31.2014.08.28.06.50.19 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Thu, 28 Aug 2014 06:50:20 -0700 (PDT) From: David Herrmann To: dri-devel@lists.freedesktop.org Subject: [PATCH v2] drm: fix division-by-zero on dumb_create() Date: Thu, 28 Aug 2014 15:50:01 +0200 Message-Id: <1409233801-11928-1-git-send-email-dh.herrmann@gmail.com> X-Mailer: git-send-email 2.1.0 Cc: Daniel Vetter X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" X-Spam-Status: No, score=-4.1 required=5.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED, FREEMAIL_FROM, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, T_DKIM_INVALID, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Kinda unexpected, but DIV_ROUND_UP() can overflow if passed an argument bigger than UINT_MAX - DIVISOR. Fix this by testing for "!cpp" before using it in the following division. Note that DIV_ROUND_UP() is defined as: #define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d)) ..this will obviously overflow if (n + d - 1) is bigger than UINT_MAX. Reported-by: Tommi Rantala Signed-off-by: David Herrmann Reviewed-by: Rob Clark --- v2: add comment that DIV_ROUND_UP() might overflow add Rob's r-b drivers/gpu/drm/drm_crtc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c index f09b752..61b6978 100644 --- a/drivers/gpu/drm/drm_crtc.c +++ b/drivers/gpu/drm/drm_crtc.c @@ -4720,8 +4720,8 @@ int drm_mode_create_dumb_ioctl(struct drm_device *dev, return -EINVAL; /* overflow checks for 32bit size calculations */ - cpp = DIV_ROUND_UP(args->bpp, 8); - if (cpp > 0xffffffffU / args->width) + cpp = DIV_ROUND_UP(args->bpp, 8); /* might overflow! */ + if (!cpp || cpp > 0xffffffffU / args->width) return -EINVAL; stride = cpp * args->width; if (args->height > 0xffffffffU / stride)