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=-16.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 BD3E2C56201 for ; Wed, 25 Nov 2020 17:19:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 56224206D9 for ; Wed, 25 Nov 2020 17:19:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="Adl6Abjm" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731226AbgKYRTX (ORCPT ); Wed, 25 Nov 2020 12:19:23 -0500 Received: from mail.kernel.org ([198.145.29.99]:38798 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729631AbgKYRTX (ORCPT ); Wed, 25 Nov 2020 12:19:23 -0500 Received: from devnote2 (NE2965lan1.rev.em-net.ne.jp [210.141.244.193]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5F59E2064B; Wed, 25 Nov 2020 17:19:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1606324762; bh=7250Ty5ORa8tN05ZttUM65BiJBw+Rs1+3H/VHisV7T8=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=Adl6AbjmXBjrLMIeQEPfbLNZipqiJ0Wnp748mP4roLYBRnmBB7woCoFG3lRpPetdg +FZzhMyXKuDaS1FKL5A2fOYAzrX/Ls3sSztUB3vYiYbIHlHppNC8z+5JSq+bqQp5tn mINjBsdMu4vdHyUEkUbNUO/cQpy/5IRn2j5P2j8k= Date: Thu, 26 Nov 2020 02:19:18 +0900 From: Masami Hiramatsu To: Borislav Petkov Cc: Andy Lutomirski , X86 ML , LKML Subject: Re: [RFC PATCH v0 10/19] x86/kprobes: Convert to insn_decode() Message-Id: <20201126021918.4401f987cf94a884511dd46e@kernel.org> In-Reply-To: <20201124101952.7909-11-bp@alien8.de> References: <20201124101952.7909-1-bp@alien8.de> <20201124101952.7909-11-bp@alien8.de> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.32; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 24 Nov 2020 11:19:43 +0100 Borislav Petkov wrote: > From: Borislav Petkov > > Simplify code, no functional changes. You've made a functional change. Improve decoding error check :) Anyway, this looks good to me. Acked-by: Masami Hiramatsu Thank you! > > Signed-off-by: Borislav Petkov > --- > arch/x86/kernel/kprobes/core.c | 17 +++++++++++------ > arch/x86/kernel/kprobes/opt.c | 9 +++++++-- > 2 files changed, 18 insertions(+), 8 deletions(-) > > diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c > index 547c7abb39f5..43d4a3056d21 100644 > --- a/arch/x86/kernel/kprobes/core.c > +++ b/arch/x86/kernel/kprobes/core.c > @@ -285,6 +285,8 @@ static int can_probe(unsigned long paddr) > /* Decode instructions */ > addr = paddr - offset; > while (addr < paddr) { > + int ret; > + > /* > * Check if the instruction has been modified by another > * kprobe, in which case we replace the breakpoint by the > @@ -296,8 +298,10 @@ static int can_probe(unsigned long paddr) > __addr = recover_probed_instruction(buf, addr); > if (!__addr) > return 0; > - kernel_insn_init(&insn, (void *)__addr, MAX_INSN_SIZE); > - insn_get_length(&insn); > + > + ret = insn_decode(&insn, (void *)__addr, MAX_INSN_SIZE, INSN_MODE_KERN); > + if (ret < 0) > + return 0; > > /* > * Another debugging subsystem might insert this breakpoint. > @@ -340,8 +344,8 @@ static int is_IF_modifier(kprobe_opcode_t *insn) > int __copy_instruction(u8 *dest, u8 *src, u8 *real, struct insn *insn) > { > kprobe_opcode_t buf[MAX_INSN_SIZE]; > - unsigned long recovered_insn = > - recover_probed_instruction(buf, (unsigned long)src); > + unsigned long recovered_insn = recover_probed_instruction(buf, (unsigned long)src); > + int ret; > > if (!recovered_insn || !insn) > return 0; > @@ -351,8 +355,9 @@ int __copy_instruction(u8 *dest, u8 *src, u8 *real, struct insn *insn) > MAX_INSN_SIZE)) > return 0; > > - kernel_insn_init(insn, dest, MAX_INSN_SIZE); > - insn_get_length(insn); > + ret = insn_decode(insn, dest, MAX_INSN_SIZE, INSN_MODE_KERN); > + if (ret < 0) > + return 0; > > /* We can not probe force emulate prefixed instruction */ > if (insn_has_emulate_prefix(insn)) > diff --git a/arch/x86/kernel/kprobes/opt.c b/arch/x86/kernel/kprobes/opt.c > index 041f0b50bc27..4d67571249e1 100644 > --- a/arch/x86/kernel/kprobes/opt.c > +++ b/arch/x86/kernel/kprobes/opt.c > @@ -299,6 +299,8 @@ static int can_optimize(unsigned long paddr) > addr = paddr - offset; > while (addr < paddr - offset + size) { /* Decode until function end */ > unsigned long recovered_insn; > + int ret; > + > if (search_exception_tables(addr)) > /* > * Since some fixup code will jumps into this function, > @@ -308,8 +310,11 @@ static int can_optimize(unsigned long paddr) > recovered_insn = recover_probed_instruction(buf, addr); > if (!recovered_insn) > return 0; > - kernel_insn_init(&insn, (void *)recovered_insn, MAX_INSN_SIZE); > - insn_get_length(&insn); > + > + ret = insn_decode(&insn, (void *)recovered_insn, MAX_INSN_SIZE, INSN_MODE_KERN); > + if (ret < 0) > + return 0; > + > /* Another subsystem puts a breakpoint */ > if (insn.opcode.bytes[0] == INT3_INSN_OPCODE) > return 0; > -- > 2.21.0 > -- Masami Hiramatsu