From patchwork Sun Mar 17 21:14:50 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jarkko Sakkinen X-Patchwork-Id: 10856631 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 56CAD1390 for ; Sun, 17 Mar 2019 21:19:00 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3E059291EE for ; Sun, 17 Mar 2019 21:19:00 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 31A4129214; Sun, 17 Mar 2019 21:19:00 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2475629200 for ; Sun, 17 Mar 2019 21:18:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727467AbfCQVS6 (ORCPT ); Sun, 17 Mar 2019 17:18:58 -0400 Received: from mga17.intel.com ([192.55.52.151]:6017 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727054AbfCQVS5 (ORCPT ); Sun, 17 Mar 2019 17:18:57 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga107.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 17 Mar 2019 14:18:57 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.58,491,1544515200"; d="scan'208";a="142817288" Received: from vanderss-mobl1.ger.corp.intel.com (HELO localhost) ([10.249.254.193]) by orsmga002.jf.intel.com with ESMTP; 17 Mar 2019 14:18:48 -0700 From: Jarkko Sakkinen To: 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, serge.ayoun@intel.com, shay.katz-zamir@intel.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 Subject: [PATCH v19 21/27] x86/fault: Add helper function to sanitize error code Date: Sun, 17 Mar 2019 23:14:50 +0200 Message-Id: <20190317211456.13927-22-jarkko.sakkinen@linux.intel.com> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190317211456.13927-1-jarkko.sakkinen@linux.intel.com> References: <20190317211456.13927-1-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 X-Virus-Scanned: ClamAV using ClamSMTP From: Sean Christopherson ...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 --- 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 78e2807fbede..5babd515f616 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -719,6 +719,18 @@ 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) { @@ -771,6 +783,8 @@ 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 +934,7 @@ __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 +1053,8 @@ 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