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=-9.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT 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 F0782C433E0 for ; Tue, 7 Jul 2020 03:06:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CDAF220663 for ; Tue, 7 Jul 2020 03:06:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727844AbgGGDGZ (ORCPT ); Mon, 6 Jul 2020 23:06:25 -0400 Received: from mga18.intel.com ([134.134.136.126]:17197 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726434AbgGGDGZ (ORCPT ); Mon, 6 Jul 2020 23:06:25 -0400 IronPort-SDR: SGiWYk0ylFhEuYYuzZYJpHNKZe2hoEi4pnhwMcmuMi7wuB3sBb4kViQynq6dgjHtVkOH0s5zPP NRUSDQ48ZJ3Q== X-IronPort-AV: E=McAfee;i="6000,8403,9674"; a="134997274" X-IronPort-AV: E=Sophos;i="5.75,321,1589266800"; d="scan'208";a="134997274" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Jul 2020 20:06:24 -0700 IronPort-SDR: H8rdP96JJlle2QV+skLHEu7RUVFaB5UPA8NBaDLVQM/G780NDnV4Yt5V8NlMCnmjAABMPSF9eU s/750C0LeHIQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.75,321,1589266800"; d="scan'208";a="388368927" Received: from apiccion-mobl1.ger.corp.intel.com (HELO localhost) ([10.249.45.178]) by fmsmga001.fm.intel.com with ESMTP; 06 Jul 2020 20:06:10 -0700 From: Jarkko Sakkinen To: x86@kernel.org, linux-sgx@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Sean Christopherson , Jethro Beekman , Jarkko Sakkinen , akpm@linux-foundation.org, andriy.shevchenko@linux.intel.com, asapek@google.com, bp@alien8.de, cedric.xing@intel.com, chenalexchen@google.com, conradparker@google.com, cyhanish@google.com, dave.hansen@intel.com, haitao.huang@intel.com, josh@joshtriplett.org, kai.huang@intel.com, kai.svahn@intel.com, kmoy@google.com, ludloff@google.com, luto@kernel.org, nhorman@redhat.com, npmccallum@redhat.com, puiterwijk@redhat.com, rientjes@google.com, tglx@linutronix.de, yaozhangx@google.com Subject: [PATCH v34 19/24] x86/fault: Add helper function to sanitize error code Date: Tue, 7 Jul 2020 06:01:59 +0300 Message-Id: <20200707030204.126021-20-jarkko.sakkinen@linux.intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200707030204.126021-1-jarkko.sakkinen@linux.intel.com> References: <20200707030204.126021-1-jarkko.sakkinen@linux.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 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. Acked-by: Jethro Beekman 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 1db6fbd7af8e..8ba78384ea73 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -556,6 +556,18 @@ 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) { @@ -612,6 +624,8 @@ 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. */ @@ -760,13 +774,7 @@ __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); @@ -885,6 +893,8 @@ 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 -- 2.25.1