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=-8.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 55F64C65BAE for ; Thu, 13 Dec 2018 21:32:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2387920811 for ; Thu, 13 Dec 2018 21:32:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2387920811 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-sgx-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726453AbeLMVcD (ORCPT ); Thu, 13 Dec 2018 16:32:03 -0500 Received: from mga03.intel.com ([134.134.136.65]:43547 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726442AbeLMVbm (ORCPT ); Thu, 13 Dec 2018 16:31:42 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by orsmga103.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 13 Dec 2018 13:31:41 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,349,1539673200"; d="scan'208";a="127709237" Received: from sjchrist-coffee.jf.intel.com ([10.54.74.154]) by fmsmga004.fm.intel.com with ESMTP; 13 Dec 2018 13:31:40 -0800 From: Sean Christopherson To: Andy Lutomirski , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, Dave Hansen , Peter Zijlstra , Jarkko Sakkinen Cc: "H. Peter Anvin" , linux-kernel@vger.kernel.org, linux-sgx@vger.kernel.org, Andy Lutomirski , Josh Triplett , Haitao Huang , Jethro Beekman , "Dr . Greg Wettstein" Subject: [RFC PATCH v4 2/5] x86/fault: Add helper function to sanitize error code Date: Thu, 13 Dec 2018 13:31:32 -0800 Message-Id: <20181213213135.12913-3-sean.j.christopherson@intel.com> X-Mailer: git-send-email 2.19.2 In-Reply-To: <20181213213135.12913-1-sean.j.christopherson@intel.com> References: <20181213213135.12913-1-sean.j.christopherson@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-sgx-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org ...to prepare for vDSO exception fixup, which will expose the error code to userspace and runs before set_signal_archinfo(), i.e. squashes the signal when fixup is successful. Signed-off-by: Sean Christopherson --- arch/x86/mm/fault.c | 26 ++++++++++++++------------ 1 file changed, 14 insertions(+), 12 deletions(-) diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 7e8a7558ca07..fefeb745d21d 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -719,18 +719,22 @@ pgtable_bad(struct pt_regs *regs, unsigned long error_code, oops_end(flags, regs, sig); } -static void set_signal_archinfo(unsigned long address, - unsigned long error_code) +static void sanitize_error_code(unsigned long address, + unsigned long *error_code) { - struct task_struct *tsk = current; - /* * To avoid leaking information about the kernel page * table layout, pretend that user-mode accesses to * kernel addresses are always protection faults. */ if (address >= TASK_SIZE_MAX) - error_code |= X86_PF_PROT; + *error_code |= X86_PF_PROT; +} + +static void set_signal_archinfo(unsigned long address, + unsigned long error_code) +{ + struct task_struct *tsk = current; tsk->thread.trap_nr = X86_TRAP_PF; tsk->thread.error_code = error_code | X86_PF_USER; @@ -771,6 +775,8 @@ no_context(struct pt_regs *regs, unsigned long error_code, * faulting through the emulate_vsyscall() logic. */ if (current->thread.sig_on_uaccess_err && signal) { + sanitize_error_code(address, &error_code); + set_signal_archinfo(address, error_code); /* XXX: hwpoison faults will set the wrong code. */ @@ -920,13 +926,7 @@ __bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code, if (is_errata100(regs, address)) return; - /* - * To avoid leaking information about the kernel page table - * layout, pretend that user-mode accesses to kernel addresses - * are always protection faults. - */ - if (address >= TASK_SIZE_MAX) - error_code |= X86_PF_PROT; + sanitize_error_code(address, &error_code); if (likely(show_unhandled_signals)) show_signal_msg(regs, error_code, address, tsk); @@ -1045,6 +1045,8 @@ do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address, if (is_prefetch(regs, error_code, address)) return; + sanitize_error_code(address, &error_code); + set_signal_archinfo(address, error_code); #ifdef CONFIG_MEMORY_FAILURE -- 2.19.2