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=-12.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 C0D47C433E2 for ; Tue, 15 Sep 2020 23:56:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7072120739 for ; Tue, 15 Sep 2020 23:56:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600214160; bh=3ULQMm7hpWaAcpBkkOaACcleGWpmlWVMlwF3OvSvACY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=kGnt0KNKxVk73m0kgWdXAHTqQLj/a+dAmLmuWTK1vCiTyjQcOgBKbOTmKxDLUAMtO Mxxlg2nrb94A5Rt9NgoP8sXhIRDcxkGD9khfxHTVyb1+jmjOVhuL59jH9HJdTsoTUP K/O8aP9R4UCJM4fM7kBnin/UnVG5XrzNy6gzR9ms= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727092AbgIOXzw (ORCPT ); Tue, 15 Sep 2020 19:55:52 -0400 Received: from mail.kernel.org ([198.145.29.99]:42760 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727050AbgIOObb (ORCPT ); Tue, 15 Sep 2020 10:31:31 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id CFFCE22261; Tue, 15 Sep 2020 14:23:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600179793; bh=3ULQMm7hpWaAcpBkkOaACcleGWpmlWVMlwF3OvSvACY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=g6HTf5Jy7mzcZk54GwJUC6qHlvLpCSFKhsrop7xc6alUKfavDpZPmU1+UkLio4Y4L iuGLa8bAhsXdNYr7EeZwpEXOXHLzLH3Yq8OHF2LW1YN0MbcOAVrqwm7bxvxNLDTCZt GLdN6xY3EkQf+j9q4Q9HTiuyWYeSF7EMyniyAVaw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot , Tetsuo Handa Subject: [PATCH 5.4 120/132] video: fbdev: fix OOB read in vga_8planes_imageblit() Date: Tue, 15 Sep 2020 16:13:42 +0200 Message-Id: <20200915140650.122334377@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200915140644.037604909@linuxfoundation.org> References: <20200915140644.037604909@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Tetsuo Handa commit bd018a6a75cebb511bb55a0e7690024be975fe93 upstream. syzbot is reporting OOB read at vga_8planes_imageblit() [1], for "cdat[y] >> 4" can become a negative value due to "const char *cdat". [1] https://syzkaller.appspot.com/bug?id=0d7a0da1557dcd1989e00cb3692b26d4173b4132 Reported-by: syzbot Signed-off-by: Tetsuo Handa Cc: stable Link: https://lore.kernel.org/r/90b55ec3-d5b0-3307-9f7c-7ff5c5fd6ad3@i-love.sakura.ne.jp Signed-off-by: Greg Kroah-Hartman --- drivers/video/fbdev/vga16fb.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/video/fbdev/vga16fb.c +++ b/drivers/video/fbdev/vga16fb.c @@ -1121,7 +1121,7 @@ static void vga_8planes_imageblit(struct char oldop = setop(0); char oldsr = setsr(0); char oldmask = selectmask(); - const char *cdat = image->data; + const unsigned char *cdat = image->data; u32 dx = image->dx; char __iomem *where; int y;