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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 201CCC433F5 for ; Mon, 3 Sep 2018 13:17:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CE2F520652 for ; Mon, 3 Sep 2018 13:17:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CE2F520652 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=zytor.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726384AbeICRhI (ORCPT ); Mon, 3 Sep 2018 13:37:08 -0400 Received: from terminus.zytor.com ([198.137.202.136]:35971 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725898AbeICRhI (ORCPT ); Mon, 3 Sep 2018 13:37:08 -0400 Received: from terminus.zytor.com (localhost [127.0.0.1]) by terminus.zytor.com (8.15.2/8.15.2) with ESMTPS id w83DGSvZ3313560 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Mon, 3 Sep 2018 06:16:28 -0700 Received: (from tipbot@localhost) by terminus.zytor.com (8.15.2/8.15.2/Submit) id w83DGSxB3313557; Mon, 3 Sep 2018 06:16:28 -0700 Date: Mon, 3 Sep 2018 06:16:28 -0700 X-Authentication-Warning: terminus.zytor.com: tipbot set sender to tipbot@zytor.com using -f From: tip-bot for Jann Horn Message-ID: Cc: anil.s.keshavamurthy@intel.com, linux-kernel@vger.kernel.org, bp@alien8.de, viro@zeniv.linux.org.uk, keescook@chromium.org, jannh@google.com, luto@kernel.org, mingo@kernel.org, tglx@linutronix.de, davem@davemloft.net, mhiramat@kernel.org, naveen.n.rao@linux.vnet.ibm.com, hpa@zytor.com Reply-To: keescook@chromium.org, jannh@google.com, anil.s.keshavamurthy@intel.com, linux-kernel@vger.kernel.org, bp@alien8.de, viro@zeniv.linux.org.uk, mhiramat@kernel.org, davem@davemloft.net, naveen.n.rao@linux.vnet.ibm.com, hpa@zytor.com, mingo@kernel.org, luto@kernel.org, tglx@linutronix.de In-Reply-To: <20180828201421.157735-3-jannh@google.com> References: <20180828201421.157735-3-jannh@google.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/core] x86/kprobes: Inline kprobe_exceptions_notify() into do_general_protection() Git-Commit-ID: 76dee4a72849561f6ffacc357cfd0aa33336081a X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 76dee4a72849561f6ffacc357cfd0aa33336081a Gitweb: https://git.kernel.org/tip/76dee4a72849561f6ffacc357cfd0aa33336081a Author: Jann Horn AuthorDate: Tue, 28 Aug 2018 22:14:16 +0200 Committer: Thomas Gleixner CommitDate: Mon, 3 Sep 2018 15:12:08 +0200 x86/kprobes: Inline kprobe_exceptions_notify() into do_general_protection() The opaque plumbing of #GP from do_general_protection() through notify_die() into kprobe_exceptions_notify() makes it hard to understand what's going on. Suggested-by: Andy Lutomirski Signed-off-by: Jann Horn Signed-off-by: Thomas Gleixner Tested-by: Kees Cook Acked-by: Masami Hiramatsu Cc: kernel-hardening@lists.openwall.com Cc: dvyukov@google.com Cc: "Naveen N. Rao" Cc: Anil S Keshavamurthy Cc: "David S. Miller" Cc: Alexander Viro Cc: linux-fsdevel@vger.kernel.org Cc: Borislav Petkov Link: https://lkml.kernel.org/r/20180828201421.157735-3-jannh@google.com --- arch/x86/kernel/kprobes/core.c | 31 +------------------------------ arch/x86/kernel/traps.c | 10 ++++++++++ 2 files changed, 11 insertions(+), 30 deletions(-) diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c index b0d1e81c96bb..467ac22691b0 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -1028,42 +1028,13 @@ int kprobe_fault_handler(struct pt_regs *regs, int trapnr) if (fixup_exception(regs, trapnr)) return 1; - /* - * fixup routine could not handle it, - * Let do_page_fault() fix it. - */ + /* fixup routine could not handle it. */ } return 0; } NOKPROBE_SYMBOL(kprobe_fault_handler); -/* - * Wrapper routine for handling exceptions. - */ -int kprobe_exceptions_notify(struct notifier_block *self, unsigned long val, - void *data) -{ - struct die_args *args = data; - int ret = NOTIFY_DONE; - - if (args->regs && user_mode(args->regs)) - return ret; - - if (val == DIE_GPF) { - /* - * To be potentially processing a kprobe fault and to - * trust the result from kprobe_running(), we have - * be non-preemptible. - */ - if (!preemptible() && kprobe_running() && - kprobe_fault_handler(args->regs, args->trapnr)) - ret = NOTIFY_STOP; - } - return ret; -} -NOKPROBE_SYMBOL(kprobe_exceptions_notify); - bool arch_within_kprobe_blacklist(unsigned long addr) { bool is_in_entry_trampoline_section = false; diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index e6db475164ed..bf9ab1aaa175 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -556,6 +556,16 @@ do_general_protection(struct pt_regs *regs, long error_code) tsk->thread.error_code = error_code; tsk->thread.trap_nr = X86_TRAP_GP; + + /* + * To be potentially processing a kprobe fault and to + * trust the result from kprobe_running(), we have to + * be non-preemptible. + */ + if (!preemptible() && kprobe_running() && + kprobe_fault_handler(regs, X86_TRAP_GP)) + return; + if (notify_die(DIE_GPF, "general protection fault", regs, error_code, X86_TRAP_GP, SIGSEGV) != NOTIFY_STOP) die("general protection fault", regs, error_code);