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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 3481DC43603 for ; Thu, 19 Dec 2019 18:37:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0045620716 for ; Thu, 19 Dec 2019 18:37:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576780667; bh=ukK3tZ03T2ojLubsfuqKbVnsJ0LNvG8yLEX+MReaYbk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=qkSHw2qB4zB4tst6mXOJnsjH3orv7ycnMLbbgX7TIIjVBeOlh7b8Zq61fHLQNT1ex MTMAgI/dEfWAFqhqRIDalbqZaKhZWZ7QRZKH85pJIMEW/3LII1/DKKKyZwDMY5NaNu xptfb5OJGO9SdTohc4NMtQJ31IXjeRJTbESJLqKA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727882AbfLSShp (ORCPT ); Thu, 19 Dec 2019 13:37:45 -0500 Received: from mail.kernel.org ([198.145.29.99]:55414 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727860AbfLSShj (ORCPT ); Thu, 19 Dec 2019 13:37:39 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 BC3B920716; Thu, 19 Dec 2019 18:37:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576780659; bh=ukK3tZ03T2ojLubsfuqKbVnsJ0LNvG8yLEX+MReaYbk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kGbruHSQtIMlc7JtiwfrTbgPmJa8Iys90ng+KqAX914QZ0jKLiXozr5eqUCdFJ/ph yT26IkkNPP1xJ4gl1BNK5nM5MeAYq0/RaYNTcs7ZshClF0oOoNE5p0sTQlgawo9rKu AwQ2ICJYj9ufqy4SSJ9pt87Un9pumTECHO8pkkqw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dan Carpenter , Chris Wilson Subject: [PATCH 4.4 063/162] drm/i810: Prevent underflow in ioctl Date: Thu, 19 Dec 2019 19:32:51 +0100 Message-Id: <20191219183211.688422226@linuxfoundation.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20191219183150.477687052@linuxfoundation.org> References: <20191219183150.477687052@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: Dan Carpenter commit 4f69851fbaa26b155330be35ce8ac393e93e7442 upstream. The "used" variables here come from the user in the ioctl and it can be negative. It could result in an out of bounds write. Signed-off-by: Dan Carpenter Reviewed-by: Chris Wilson Signed-off-by: Chris Wilson Link: https://patchwork.freedesktop.org/patch/msgid/20191004102251.GC823@mwanda Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/i810/i810_dma.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/drivers/gpu/drm/i810/i810_dma.c +++ b/drivers/gpu/drm/i810/i810_dma.c @@ -723,7 +723,7 @@ static void i810_dma_dispatch_vertex(str if (nbox > I810_NR_SAREA_CLIPRECTS) nbox = I810_NR_SAREA_CLIPRECTS; - if (used > 4 * 1024) + if (used < 0 || used > 4 * 1024) used = 0; if (sarea_priv->dirty) @@ -1043,7 +1043,7 @@ static void i810_dma_dispatch_mc(struct if (u != I810_BUF_CLIENT) DRM_DEBUG("MC found buffer that isn't mine!\n"); - if (used > 4 * 1024) + if (used < 0 || used > 4 * 1024) used = 0; sarea_priv->dirty = 0x7f;