From patchwork Wed Oct 2 16:43:39 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Herrmann X-Patchwork-Id: 2976101 Return-Path: X-Original-To: patchwork-linux-fbdev@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 65BB39F2B8 for ; Wed, 2 Oct 2013 16:44:13 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id C12892043C for ; Wed, 2 Oct 2013 16:44:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5CC3C2044B for ; Wed, 2 Oct 2013 16:44:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754635Ab3JBQno (ORCPT ); Wed, 2 Oct 2013 12:43:44 -0400 Received: from mail-ea0-f176.google.com ([209.85.215.176]:62446 "EHLO mail-ea0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753659Ab3JBQnm (ORCPT ); Wed, 2 Oct 2013 12:43:42 -0400 Received: by mail-ea0-f176.google.com with SMTP id q16so529235ead.21 for ; Wed, 02 Oct 2013 09:43:41 -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:in-reply-to:references; bh=YHrd/yavglzIxqvLFccUNTPoTHdNmnuiNj44efbODjI=; b=qIup6dd+GW4S6Y3Bxajh67v+kUso6k0t/pSCcLoHVAXcwPOIgBo5HsC0GN1vemqK9u puSiupN1TiC6+nMwKkB2+g++b4OpYlyulVCb677cnAjWXRL7vMs7qtSAIqFuq/D/8Y1n 1eFYJnBQt3B7HhiVwkHkIkMa9Ohcc8zC7NvqradkM/zML3mo+9oiXkanyfr5hGyNvQEs oSW0zQfl/KSFnSQvWUkwQEN7drnJ10twAqMIPZGAKl2QenPC0rGvFNycbTTV9Q3wMEPX +IR/vF0gA1XZVuzdvOQ6mdcv4jF1F/xynyyLISjECn2/AbiQZPoyDe3vy3Oh4oqydFt/ rJPQ== X-Received: by 10.14.9.72 with SMTP id 48mr4917676ees.42.1380732221480; Wed, 02 Oct 2013 09:43:41 -0700 (PDT) Received: from localhost.localdomain (stgt-5f71b885.pool.mediaWays.net. [95.113.184.133]) by mx.google.com with ESMTPSA id n48sm5565657eeg.17.1969.12.31.16.00.00 (version=TLSv1.2 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 02 Oct 2013 09:43:40 -0700 (PDT) From: David Herrmann To: linux-fbdev@vger.kernel.org Cc: James Bates , linux-kernel@vger.kernel.org, Tomi Valkeinen , Jean-Christophe Plagniol-Villard , David Herrmann Subject: [PATCH v3] efifb: prevent null-deref when iterating dmi_list Date: Wed, 2 Oct 2013 18:43:39 +0200 Message-Id: <1380732219-5458-1-git-send-email-dh.herrmann@gmail.com> X-Mailer: git-send-email 1.8.4 In-Reply-To: <1380732056-5387-1-git-send-email-dh.herrmann@gmail.com> References: <1380732056-5387-1-git-send-email-dh.herrmann@gmail.com> Sender: linux-fbdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org X-Spam-Status: No, score=-7.4 required=5.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED, FREEMAIL_FROM, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, T_DKIM_INVALID, UNPARSEABLE_RELAY autolearn=ham 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 From: James Bates The dmi_list array is initialized using gnu designated initializers, and therefore may contain fewer explicitly defined entries as there are elements in it. This is because the enum above with M_xyz constants contains more items than the designated initializer. Those elements not explicitly initialized are implicitly set to 0. Now efifb_setup() loops through all these array elements, and performs a strcmp on each item. For non explicitly initialized elements this will be a null pointer: This patch swaps the check order in the if statement, thus checks first whether dmi_list[i].base is null. Signed-off-by: James Bates Signed-off-by: David Herrmann --- v3: fixes the "Author" field and James' email address drivers/video/efifb.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/video/efifb.c b/drivers/video/efifb.c index 7f9ff75..fcb9500 100644 --- a/drivers/video/efifb.c +++ b/drivers/video/efifb.c @@ -108,8 +108,8 @@ static int efifb_setup(char *options) if (!*this_opt) continue; for (i = 0; i < M_UNKNOWN; i++) { - if (!strcmp(this_opt, efifb_dmi_list[i].optname) && - efifb_dmi_list[i].base != 0) { + if (efifb_dmi_list[i].base != 0 && + !strcmp(this_opt, efifb_dmi_list[i].optname)) { screen_info.lfb_base = efifb_dmi_list[i].base; screen_info.lfb_linelength = efifb_dmi_list[i].stride; screen_info.lfb_width = efifb_dmi_list[i].width;