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[209.132.180.67]) by mx.google.com with ESMTP id i10si4851598pfr.130.2019.07.13.10.13.09; Sat, 13 Jul 2019 10:13:24 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=intel.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728240AbfGMRMS (ORCPT + 99 others); Sat, 13 Jul 2019 13:12:18 -0400 Received: from mga03.intel.com ([134.134.136.65]:46352 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727853AbfGMRMR (ORCPT ); Sat, 13 Jul 2019 13:12:17 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orsmga103.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 13 Jul 2019 10:12:17 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.63,487,1557212400"; d="scan'208";a="341981584" Received: from hbriegel-mobl.ger.corp.intel.com (HELO localhost) ([10.252.50.48]) by orsmga005.jf.intel.com with ESMTP; 13 Jul 2019 10:12:08 -0700 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, 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, cedric.xing@intel.com Subject: [PATCH v21 21/28] x86/fault: Add helper function to sanitize error code Date: Sat, 13 Jul 2019 20:07:57 +0300 Message-Id: <20190713170804.2340-22-jarkko.sakkinen@linux.intel.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190713170804.2340-1-jarkko.sakkinen@linux.intel.com> References: <20190713170804.2340-1-jarkko.sakkinen@linux.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 117262676e93..140f1196f819 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -701,6 +701,18 @@ 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) { @@ -757,6 +769,8 @@ 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. */ @@ -905,13 +919,7 @@ __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); @@ -1028,6 +1036,8 @@ 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 -- 2.20.1