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=-9.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,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 36595C43387 for ; Wed, 26 Dec 2018 22:58:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 072002070B for ; Wed, 26 Dec 2018 22:58:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1545865101; bh=y2pTSpCZ8iFSQV7vvXiimMCquqvPXMpv331xLSUgoTs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=TD1aGrY+m7vJcS6T2cPeez25s74A0ctdJjDYAFU1cME7+q+e5E1p6UBA6rTuG1E/4 jtZEZwJ3BYTNqsmDroQyTiUv8PHrY6OI6bMJV+hs2t5cTFLxr6Mu77xeXhGLzxgbp7 AujWsDh/G1wA4nT1DucEzqqzmKCSp/OmDeXvmOsk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730488AbeLZW6T (ORCPT ); Wed, 26 Dec 2018 17:58:19 -0500 Received: from mail.kernel.org ([198.145.29.99]:58552 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729393AbeLZW5c (ORCPT ); Wed, 26 Dec 2018 17:57:32 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 8974321741; Wed, 26 Dec 2018 22:57:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1545865052; bh=y2pTSpCZ8iFSQV7vvXiimMCquqvPXMpv331xLSUgoTs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0P/Uckm7M/0HJpja+8RBnMICXi7sCTDioDZKKU6/Geu+58e/zbzICtTr2weWBUbrO d9rKpb7IvbKGGPku+OlCwcvfgVJBnGo1dClucU7enS9da76VNx2h+y/dKSdxmtgH9D MgaSe+BLU5AK0Z4vjhZepolnW5pZgs89sY3Ovnwc= From: Sasha Levin To: stable@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Colin Ian King , Thomas Gleixner , security@kernel.org, Sasha Levin Subject: [PATCH AUTOSEL 4.4 16/21] x86/mtrr: Don't copy uninitialized gentry fields back to userspace Date: Wed, 26 Dec 2018 17:54:54 -0500 Message-Id: <20181226225501.151365-16-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181226225501.151365-1-sashal@kernel.org> References: <20181226225501.151365-1-sashal@kernel.org> MIME-Version: 1.0 X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Colin Ian King [ Upstream commit 32043fa065b51e0b1433e48d118821c71b5cd65d ] Currently the copy_to_user of data in the gentry struct is copying uninitiaized data in field _pad from the stack to userspace. Fix this by explicitly memset'ing gentry to zero, this also will zero any compiler added padding fields that may be in struct (currently there are none). Detected by CoverityScan, CID#200783 ("Uninitialized scalar variable") Fixes: b263b31e8ad6 ("x86, mtrr: Use explicit sizing and padding for the 64-bit ioctls") Signed-off-by: Colin Ian King Signed-off-by: Thomas Gleixner Reviewed-by: Tyler Hicks Cc: security@kernel.org Link: https://lkml.kernel.org/r/20181218172956.1440-1-colin.king@canonical.com Signed-off-by: Sasha Levin --- arch/x86/kernel/cpu/mtrr/if.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/x86/kernel/cpu/mtrr/if.c b/arch/x86/kernel/cpu/mtrr/if.c index d76f13d6d8d6..ec894bf5eeb0 100644 --- a/arch/x86/kernel/cpu/mtrr/if.c +++ b/arch/x86/kernel/cpu/mtrr/if.c @@ -173,6 +173,8 @@ mtrr_ioctl(struct file *file, unsigned int cmd, unsigned long __arg) struct mtrr_gentry gentry; void __user *arg = (void __user *) __arg; + memset(&gentry, 0, sizeof(gentry)); + switch (cmd) { case MTRRIOC_ADD_ENTRY: case MTRRIOC_SET_ENTRY: -- 2.19.1