From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932584AbeDWVew (ORCPT ); Mon, 23 Apr 2018 17:34:52 -0400 Received: from vps-vb.mhejs.net ([37.28.154.113]:41014 "EHLO vps-vb.mhejs.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932499AbeDWVem (ORCPT ); Mon, 23 Apr 2018 17:34:42 -0400 From: "Maciej S. Szmigiero" To: Borislav Petkov Cc: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v5 1/6] x86/microcode/AMD: Subtract SECTION_HDR_SIZE from file leftover length Date: Mon, 23 Apr 2018 23:34:06 +0200 Message-Id: <572982c62551739903c5f7f2a70e3962fdb135a7.1524515406.git.mail@maciej.szmigiero.name> X-Mailer: git-send-email 2.17.0 In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org verify_patch_size() verifies whether the remaining size of the microcode container file is large enough to contain a patch of the indicated size. However, the section header length is not included in this indicated size but it is present in the leftover file length so it should be subtracted from the leftover file length before passing this value to verify_patch_size(). Signed-off-by: Maciej S. Szmigiero Link: http://lkml.kernel.org/r/b4854b17-e3ba-54d6-488d-0e0bfffe4c71@maciej.szmigiero.name [ Split comment. ] Signed-off-by: Borislav Petkov --- arch/x86/kernel/cpu/microcode/amd.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c index 0624957aa068..dc8ea9a9d962 100644 --- a/arch/x86/kernel/cpu/microcode/amd.c +++ b/arch/x86/kernel/cpu/microcode/amd.c @@ -461,8 +461,12 @@ static int collect_cpu_info_amd(int cpu, struct cpu_signature *csig) return 0; } -static unsigned int verify_patch_size(u8 family, u32 patch_size, - unsigned int size) +/* + * Check whether the passed remaining file @size is large enough to contain a + * patch of the indicated @patch_size (and also whether this size does not + * exceed the per-family maximum). + */ +static unsigned int verify_patch_size(u8 family, u32 patch_size, unsigned int size) { u32 max_size; @@ -613,7 +617,12 @@ static int verify_and_add_patch(u8 family, u8 *fw, unsigned int leftover) return crnt_size; } - ret = verify_patch_size(family, patch_size, leftover); + /* + * The section header length is not included in this indicated size + * but is present in the leftover file length so we need to subtract + * it before passing this value to the function below. + */ + ret = verify_patch_size(family, patch_size, leftover - SECTION_HDR_SIZE); if (!ret) { pr_err("Patch-ID 0x%08x: size mismatch.\n", mc_hdr->patch_id); return crnt_size;