From patchwork Fri May 31 23:31:52 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 10971083 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 991E5112C for ; Fri, 31 May 2019 23:33:27 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 89F8228D9E for ; Fri, 31 May 2019 23:33:27 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 7D88028D9F; Fri, 31 May 2019 23:33:27 +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=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=unavailable 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 5AB3A28DA1 for ; Fri, 31 May 2019 23:33:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727086AbfEaXdZ (ORCPT ); Fri, 31 May 2019 19:33:25 -0400 Received: from mga07.intel.com ([134.134.136.100]:59345 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726635AbfEaXcb (ORCPT ); Fri, 31 May 2019 19:32:31 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga105.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 31 May 2019 16:32:30 -0700 X-ExtLoop1: 1 Received: from sjchrist-coffee.jf.intel.com ([10.54.74.36]) by orsmga008.jf.intel.com with ESMTP; 31 May 2019 16:32:30 -0700 From: Sean Christopherson To: Jarkko Sakkinen Cc: Andy Lutomirski , Cedric Xing , Stephen Smalley , James Morris , "Serge E . Hallyn" , LSM List , Paul Moore , Eric Paris , selinux@vger.kernel.org, Jethro Beekman , Dave Hansen , Thomas Gleixner , Linus Torvalds , LKML , X86 ML , linux-sgx@vger.kernel.org, Andrew Morton , nhorman@redhat.com, npmccallum@redhat.com, Serge Ayoun , Shay Katz-zamir , Haitao Huang , Andy Shevchenko , Kai Svahn , Borislav Petkov , Josh Triplett , Kai Huang , David Rientjes , William Roberts , Philip Tricca Subject: [RFC PATCH 2/9] x86/sgx: Do not naturally align MAP_FIXED address Date: Fri, 31 May 2019 16:31:52 -0700 Message-Id: <20190531233159.30992-3-sean.j.christopherson@intel.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190531233159.30992-1-sean.j.christopherson@intel.com> References: <20190531233159.30992-1-sean.j.christopherson@intel.com> MIME-Version: 1.0 Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: X-Virus-Scanned: ClamAV using ClamSMTP SGX enclaves have an associated Enclave Linear Range (ELRANGE) that is tracked and enforced by the CPU using a base+mask approach, similar to how hardware range registers such as the variable MTRRs. As a result, the ELRANGE must be naturally sized and aligned. To reduce boilerplate code that would be needed in every userspace enclave loader, the SGX driver naturally aligns the mmap() address and also requires the range to be naturally sized. Unfortunately, SGX fails to grant a waiver to the MAP_FIXED case, e.g. incorrectly rejects mmap() if userspace is attempting to map a small slice of an existing enclave. Signed-off-by: Sean Christopherson --- arch/x86/kernel/cpu/sgx/driver/main.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/cpu/sgx/driver/main.c b/arch/x86/kernel/cpu/sgx/driver/main.c index afe844aa81d6..129d356aff30 100644 --- a/arch/x86/kernel/cpu/sgx/driver/main.c +++ b/arch/x86/kernel/cpu/sgx/driver/main.c @@ -79,7 +79,13 @@ static unsigned long sgx_get_unmapped_area(struct file *file, unsigned long pgoff, unsigned long flags) { - if (len < 2 * PAGE_SIZE || len & (len - 1) || flags & MAP_PRIVATE) + if (flags & MAP_PRIVATE) + return -EINVAL; + + if (flags & MAP_FIXED) + return addr; + + if (len < 2 * PAGE_SIZE || len & (len - 1)) return -EINVAL; addr = current->mm->get_unmapped_area(file, addr, 2 * len, pgoff,