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=-12.0 required=3.0 tests=BAYES_00,INCLUDES_PATCH, MAILING_LIST_MULTI,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 B4939C433FE for ; Fri, 4 Dec 2020 10:56:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6AE23229F0 for ; Fri, 4 Dec 2020 10:56:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729792AbgLDKzz (ORCPT ); Fri, 4 Dec 2020 05:55:55 -0500 Received: from mail.kernel.org ([198.145.29.99]:51164 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726014AbgLDKzz (ORCPT ); Fri, 4 Dec 2020 05:55:55 -0500 From: Masami Hiramatsu Authentication-Results: mail.kernel.org; dkim=permerror (bad message/signature format) To: x86@kernel.org, Thomas Gleixner , Ingo Molnar , Borislav Petkov Cc: Kees Cook , Masami Hiramatsu , "H . Peter Anvin" , Joerg Roedel , Tom Lendacky , "Gustavo A . R . Silva" , Jann Horn , Srikar Dronamraju , Ricardo Neri , linux-kernel@vger.kernel.org Subject: [PATCH v3 0/3] x86/insn: Fix not using prefixes.nbytes for loop over prefixes.bytes Date: Fri, 4 Dec 2020 19:55:09 +0900 Message-Id: <160707930875.3296595.12884856538916078988.stgit@devnote2> X-Mailer: git-send-email 2.25.1 User-Agent: StGit/0.19 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Here are the 3rd version of patches to fix the wrong loop boundary check on insn.prefixes.bytes[] array. The previous version is here; https://lkml.kernel.org/r/160697102582.3146288.10127018634865687932.stgit@devnote2 In this version, I've fixed some comments, added NUM_INSN_FIELD_BYTES and MAX_LEGACY_PREFIX_GROUPS macros and commented on it. Kees Cook got a syzbot warning and found this issue and there were similar wrong boundary check patterns in the x86 code. Since the insn.prefixes.nbytes can be bigger than the size of insn.prefixes.bytes[] when a same prefix is repeated, we have to check whether the insn.prefixes.bytes[i] != 0 (*) and i < 4 instead of insn.prefixes.nbytes. (*) Note that insn.prefixes.bytes[] should be zeroed in insn_init() before decoding, and 0x00 is not a legacy prefix. So if you see 0 on insn.prefix.bytes[], it indicates the end of the array. Or, if the prefixes.bytes[] is filled with prefix bytes, we can check the index is less than 4. Thank you, --- Masami Hiramatsu (3): x86/uprobes: Fix not using prefixes.nbytes for loop over prefixes.bytes x86/insn-eval: Fix not using prefixes.nbytes for loop over prefixes.bytes x86/sev-es: Fix not using prefixes.nbytes for loop over prefixes.bytes arch/x86/boot/compressed/sev-es.c | 5 ++-- arch/x86/include/asm/insn.h | 49 ++++++++++++++++++++++++++++++++++++- arch/x86/kernel/uprobes.c | 10 +++++--- arch/x86/lib/insn-eval.c | 10 ++++---- arch/x86/lib/insn.c | 2 +- tools/arch/x86/include/asm/insn.h | 49 ++++++++++++++++++++++++++++++++++++- tools/arch/x86/lib/insn.c | 2 +- 7 files changed, 111 insertions(+), 16 deletions(-) -- Masami Hiramatsu (Linaro)