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=-17.0 required=3.0 tests=BAYES_00,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,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 70B0AC64E8A for ; Wed, 2 Dec 2020 08:52:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1AFB0221FB for ; Wed, 2 Dec 2020 08:52:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387991AbgLBIwD (ORCPT ); Wed, 2 Dec 2020 03:52:03 -0500 Received: from mail.kernel.org ([198.145.29.99]:36704 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387721AbgLBIwC (ORCPT ); Wed, 2 Dec 2020 03:52:02 -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 2/3] x86/uprobes: Fix not using prefixes.nbytes for loop over prefixes.bytes Date: Wed, 2 Dec 2020 17:51:16 +0900 Message-Id: <160689907597.3084105.18019089399087866918.stgit@devnote2> X-Mailer: git-send-email 2.25.1 In-Reply-To: <160689905099.3084105.7880450206184269465.stgit@devnote2> References: <160689905099.3084105.7880450206184269465.stgit@devnote2> 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 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. Fixes: 2b1444983508 ("uprobes, mm, x86: Add the ability to install and remove uprobes breakpoints") Cc: stable@vger.kernel.org Reported-by: Kees Cook Signed-off-by: Masami Hiramatsu --- arch/x86/kernel/uprobes.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c index 3fdaa042823d..bb3ea3705b99 100644 --- a/arch/x86/kernel/uprobes.c +++ b/arch/x86/kernel/uprobes.c @@ -257,7 +257,7 @@ static bool is_prefix_bad(struct insn *insn) { int i; - for (i = 0; i < insn->prefixes.nbytes; i++) { + for (i = 0; insn->prefixes.bytes[i] && i < 4; i++) { insn_attr_t attr; attr = inat_get_opcode_attribute(insn->prefixes.bytes[i]); @@ -746,7 +746,7 @@ static int branch_setup_xol_ops(struct arch_uprobe *auprobe, struct insn *insn) * Intel and AMD behavior differ in 64-bit mode: Intel ignores 66 prefix. * No one uses these insns, reject any branch insns with such prefix. */ - for (i = 0; i < insn->prefixes.nbytes; i++) { + for (i = 0; insn->prefixes.bytes[i] && i < 4; i++) { if (insn->prefixes.bytes[i] == 0x66) return -ENOTSUPP; }