Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753942AbbGASlT (ORCPT ); Wed, 1 Jul 2015 14:41:19 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:44750 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751675AbbGASka (ORCPT ); Wed, 1 Jul 2015 14:40:30 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Quentin Casasnovas , "H. Peter Anvin" , Fenghua Yu , Borislav Petkov , Jiri Slaby , Sheng Yong Subject: [PATCH 3.10 14/22] x86/microcode/intel: Guard against stack overflow in the loader Date: Wed, 1 Jul 2015 11:40:19 -0700 Message-Id: <20150701183942.578303031@linuxfoundation.org> X-Mailer: git-send-email 2.4.4 In-Reply-To: <20150701183942.019582154@linuxfoundation.org> References: <20150701183942.019582154@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1685 Lines: 44 3.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Quentin Casasnovas commit f84598bd7c851f8b0bf8cd0d7c3be0d73c432ff4 upstream. 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 Signed-off-by: Jiri Slaby Signed-off-by: Sheng Yong Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/microcode_intel_early.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/x86/kernel/microcode_intel_early.c +++ b/arch/x86/kernel/microcode_intel_early.c @@ -321,7 +321,7 @@ get_matching_model_microcode(int cpu, un 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); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/