From patchwork Sun Dec 6 09:09:30 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: thermal-bot for Julien Panis X-Patchwork-Id: 339132 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=-20.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING, SPF_HELO_NONE, SPF_PASS 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 1C7BFC433FE for ; Sun, 6 Dec 2020 09:10:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D164F222F9 for ; Sun, 6 Dec 2020 09:10:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726288AbgLFJKP (ORCPT ); Sun, 6 Dec 2020 04:10:15 -0500 Received: from Galois.linutronix.de ([193.142.43.55]:57308 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726209AbgLFJKN (ORCPT ); Sun, 6 Dec 2020 04:10:13 -0500 Date: Sun, 06 Dec 2020 09:09:30 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1607245771; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=eY7RW9wRlLumLKbgtN+8B1XUsllLVvHZSgoZDgKOR9Q=; b=Wy01ux/BJ0ZbZiUePS8O7VgFkfKVsqr5qbunWjRinZdgzGq5om3nUvg4SjrjJj8sr8WbWB iInlaCw9CexqQoefZ73fSk7jixpnFDony0ZrOcz2mpKOytV8u9d9ygt3D5ZllCzRiwrzMn qJWLlHP6ZGhf3Mu8gtljJTLR+Ajs77V1oDJBfgVZpqxVDSxiAjODsUyMZthxVDVickrx5P Cw55QKssavGKhoW2+FLtQfubpAs8tcfh4sVNwLx68oN9hzJH3wcn8/WmWT8wN8KrRCnYYi /gh7EKy4NFHPe9Zk/DqvF+qlYRKGZ376gTowNohqbhbbk1pEWvDPqrGSWGDl+g== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1607245771; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=eY7RW9wRlLumLKbgtN+8B1XUsllLVvHZSgoZDgKOR9Q=; b=2WcGV9cdads9H/dgce/ucbXISjlcR4m51XpZkMn0EEt8OvQCHEl0R6ZJDJBxrBqJIh9CTD Xt1MlM6QWq3A5OBg== From: "tip-bot2 for Masami Hiramatsu" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/urgent] x86/uprobes: Do not use prefixes.nbytes when looping over prefixes.bytes Cc: syzbot+9b64b619f10f19d19a7c@syzkaller.appspotmail.com, Masami Hiramatsu , Borislav Petkov , Srikar Dronamraju , stable@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <160697103739.3146288.7437620795200799020.stgit@devnote2> References: <160697103739.3146288.7437620795200799020.stgit@devnote2> MIME-Version: 1.0 Message-ID: <160724577086.3364.16453446433031160252.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The following commit has been merged into the x86/urgent branch of tip: Commit-ID: 4e9a5ae8df5b3365183150f6df49e49dece80d8c Gitweb: https://git.kernel.org/tip/4e9a5ae8df5b3365183150f6df49e49dece80d8c Author: Masami Hiramatsu AuthorDate: Thu, 03 Dec 2020 13:50:37 +09:00 Committer: Borislav Petkov CommitterDate: Sun, 06 Dec 2020 09:58:13 +01:00 x86/uprobes: Do not use prefixes.nbytes when looping over prefixes.bytes Since insn.prefixes.nbytes can be bigger than the size of insn.prefixes.bytes[] when a prefix is repeated, the proper check must be insn.prefixes.bytes[i] != 0 and i < 4 instead of using insn.prefixes.nbytes. Introduce a for_each_insn_prefix() macro for this purpose. Debugged by Kees Cook . [ bp: Massage commit message, sync with the respective header in tools/ and drop "we". ] Fixes: 2b1444983508 ("uprobes, mm, x86: Add the ability to install and remove uprobes breakpoints") Reported-by: syzbot+9b64b619f10f19d19a7c@syzkaller.appspotmail.com Signed-off-by: Masami Hiramatsu Signed-off-by: Borislav Petkov Reviewed-by: Srikar Dronamraju Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/160697103739.3146288.7437620795200799020.stgit@devnote2 --- arch/x86/include/asm/insn.h | 15 +++++++++++++++ arch/x86/kernel/uprobes.c | 10 ++++++---- tools/arch/x86/include/asm/insn.h | 15 +++++++++++++++ 3 files changed, 36 insertions(+), 4 deletions(-) diff --git a/arch/x86/include/asm/insn.h b/arch/x86/include/asm/insn.h index 5c1ae3e..a8c3d28 100644 --- a/arch/x86/include/asm/insn.h +++ b/arch/x86/include/asm/insn.h @@ -201,6 +201,21 @@ static inline int insn_offset_immediate(struct insn *insn) return insn_offset_displacement(insn) + insn->displacement.nbytes; } +/** + * for_each_insn_prefix() -- Iterate prefixes in the instruction + * @insn: Pointer to struct insn. + * @idx: Index storage. + * @prefix: Prefix byte. + * + * Iterate prefix bytes of given @insn. Each prefix byte is stored in @prefix + * and the index is stored in @idx (note that this @idx is just for a cursor, + * do not change it.) + * Since prefixes.nbytes can be bigger than 4 if some prefixes + * are repeated, it cannot be used for looping over the prefixes. + */ +#define for_each_insn_prefix(insn, idx, prefix) \ + for (idx = 0; idx < ARRAY_SIZE(insn->prefixes.bytes) && (prefix = insn->prefixes.bytes[idx]) != 0; idx++) + #define POP_SS_OPCODE 0x1f #define MOV_SREG_OPCODE 0x8e diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c index 3fdaa04..138bdb1 100644 --- a/arch/x86/kernel/uprobes.c +++ b/arch/x86/kernel/uprobes.c @@ -255,12 +255,13 @@ static volatile u32 good_2byte_insns[256 / 32] = { static bool is_prefix_bad(struct insn *insn) { + insn_byte_t p; int i; - for (i = 0; i < insn->prefixes.nbytes; i++) { + for_each_insn_prefix(insn, i, p) { insn_attr_t attr; - attr = inat_get_opcode_attribute(insn->prefixes.bytes[i]); + attr = inat_get_opcode_attribute(p); switch (attr) { case INAT_MAKE_PREFIX(INAT_PFX_ES): case INAT_MAKE_PREFIX(INAT_PFX_CS): @@ -715,6 +716,7 @@ static const struct uprobe_xol_ops push_xol_ops = { static int branch_setup_xol_ops(struct arch_uprobe *auprobe, struct insn *insn) { u8 opc1 = OPCODE1(insn); + insn_byte_t p; int i; switch (opc1) { @@ -746,8 +748,8 @@ 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++) { - if (insn->prefixes.bytes[i] == 0x66) + for_each_insn_prefix(insn, i, p) { + if (p == 0x66) return -ENOTSUPP; } diff --git a/tools/arch/x86/include/asm/insn.h b/tools/arch/x86/include/asm/insn.h index 568854b..52c6262 100644 --- a/tools/arch/x86/include/asm/insn.h +++ b/tools/arch/x86/include/asm/insn.h @@ -201,6 +201,21 @@ static inline int insn_offset_immediate(struct insn *insn) return insn_offset_displacement(insn) + insn->displacement.nbytes; } +/** + * for_each_insn_prefix() -- Iterate prefixes in the instruction + * @insn: Pointer to struct insn. + * @idx: Index storage. + * @prefix: Prefix byte. + * + * Iterate prefix bytes of given @insn. Each prefix byte is stored in @prefix + * and the index is stored in @idx (note that this @idx is just for a cursor, + * do not change it.) + * Since prefixes.nbytes can be bigger than 4 if some prefixes + * are repeated, it cannot be used for looping over the prefixes. + */ +#define for_each_insn_prefix(insn, idx, prefix) \ + for (idx = 0; idx < ARRAY_SIZE(insn->prefixes.bytes) && (prefix = insn->prefixes.bytes[idx]) != 0; idx++) + #define POP_SS_OPCODE 0x1f #define MOV_SREG_OPCODE 0x8e