From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752972AbbBST2e (ORCPT ); Thu, 19 Feb 2015 14:28:34 -0500 Received: from terminus.zytor.com ([198.137.202.10]:58138 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752730AbbBST2c (ORCPT ); Thu, 19 Feb 2015 14:28:32 -0500 Date: Thu, 19 Feb 2015 11:28:12 -0800 From: tip-bot for Quentin Casasnovas Message-ID: Cc: fenghua.yu@intel.com, quentin.casasnovas@oracle.com, hpa@zytor.com, linux-kernel@vger.kernel.org, bp@suse.de, mingo@kernel.org, tglx@linutronix.de Reply-To: bp@suse.de, mingo@kernel.org, tglx@linutronix.de, linux-kernel@vger.kernel.org, hpa@zytor.com, quentin.casasnovas@oracle.com, fenghua.yu@intel.com In-Reply-To: <1422964824-22056-1-git-send-email-quentin.casasnovas@oracle.com> References: <1422964824-22056-1-git-send-email-quentin.casasnovas@oracle.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/urgent] x86/microcode/intel: Guard against stack overflow in the loader Git-Commit-ID: f84598bd7c851f8b0bf8cd0d7c3be0d73c432ff4 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: f84598bd7c851f8b0bf8cd0d7c3be0d73c432ff4 Gitweb: http://git.kernel.org/tip/f84598bd7c851f8b0bf8cd0d7c3be0d73c432ff4 Author: Quentin Casasnovas AuthorDate: Tue, 3 Feb 2015 13:00:22 +0100 Committer: Borislav Petkov CommitDate: Thu, 19 Feb 2015 12:41:37 +0100 x86/microcode/intel: Guard against stack overflow in the loader mc_saved_tmp is a static array allocated on the stack, we need to make sure mc_saved_count stays within its bounds, otherwise we're overflowing the stack in _save_mc(). A specially crafted microcode header could lead to a kernel crash or potentially kernel execution. Signed-off-by: Quentin Casasnovas Cc: "H. Peter Anvin" Cc: Fenghua Yu Link: http://lkml.kernel.org/r/1422964824-22056-1-git-send-email-quentin.casasnovas@oracle.com Signed-off-by: Borislav Petkov --- arch/x86/kernel/cpu/microcode/intel_early.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kernel/cpu/microcode/intel_early.c b/arch/x86/kernel/cpu/microcode/intel_early.c index ec9df6f..5e109a3 100644 --- a/arch/x86/kernel/cpu/microcode/intel_early.c +++ b/arch/x86/kernel/cpu/microcode/intel_early.c @@ -321,7 +321,7 @@ get_matching_model_microcode(int cpu, unsigned long start, unsigned int mc_saved_count = mc_saved_data->mc_saved_count; int i; - while (leftover) { + while (leftover && mc_saved_count < ARRAY_SIZE(mc_saved_tmp)) { mc_header = (struct microcode_header_intel *)ucode_ptr; mc_size = get_totalsize(mc_header);