From patchwork Sun Feb 23 17:25:54 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jarkko Sakkinen X-Patchwork-Id: 11398953 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id E95C8109A for ; Sun, 23 Feb 2020 17:28:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D24042067D for ; Sun, 23 Feb 2020 17:28:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727272AbgBWR2j (ORCPT ); Sun, 23 Feb 2020 12:28:39 -0500 Received: from mga11.intel.com ([192.55.52.93]:60088 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726884AbgBWR2j (ORCPT ); Sun, 23 Feb 2020 12:28:39 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 23 Feb 2020 09:28:38 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,476,1574150400"; d="scan'208";a="229650234" Received: from ajbergin-mobl.ger.corp.intel.com (HELO localhost) ([10.252.23.203]) by fmsmga007.fm.intel.com with ESMTP; 23 Feb 2020 09:28:32 -0800 From: Jarkko Sakkinen To: linux-kernel@vger.kernel.org, x86@kernel.org, linux-sgx@vger.kernel.org Cc: akpm@linux-foundation.org, dave.hansen@intel.com, sean.j.christopherson@intel.com, nhorman@redhat.com, npmccallum@redhat.com, haitao.huang@intel.com, andriy.shevchenko@linux.intel.com, tglx@linutronix.de, kai.svahn@intel.com, bp@alien8.de, josh@joshtriplett.org, luto@kernel.org, kai.huang@intel.com, rientjes@google.com, cedric.xing@intel.com, puiterwijk@redhat.com, Jarkko Sakkinen Subject: [PATCH v27 17/22] x86/fault: Add helper function to sanitize error code Date: Sun, 23 Feb 2020 19:25:54 +0200 Message-Id: <20200223172559.6912-18-jarkko.sakkinen@linux.intel.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200223172559.6912-1-jarkko.sakkinen@linux.intel.com> References: <20200223172559.6912-1-jarkko.sakkinen@linux.intel.com> MIME-Version: 1.0 Sender: linux-sgx-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org From: Sean Christopherson Add helper function to sanitize error code to prepare for vDSO exception fixup, which will expose the error code to userspace and runs before set_signal_archinfo(), i.e. suppresses the signal when fixup is successful. Signed-off-by: Sean Christopherson Signed-off-by: Jarkko Sakkinen --- arch/x86/mm/fault.c | 24 +++++++++++++++++------- 1 file changed, 17 insertions(+), 7 deletions(-) diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index dee9504cde79..6b662d272af6 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -682,6 +682,18 @@ pgtable_bad(struct pt_regs *regs, unsigned long error_code, oops_end(flags, regs, sig); } +static void sanitize_error_code(unsigned long address, + unsigned long *error_code) +{ + /* + * 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; +} + static void set_signal_archinfo(unsigned long address, unsigned long error_code) { @@ -738,6 +750,8 @@ 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. */ @@ -886,13 +900,7 @@ __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); @@ -1009,6 +1017,8 @@ 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