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=-8.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 46AD2C677FC for ; Thu, 11 Oct 2018 15:24:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 170BD213A2 for ; Thu, 11 Oct 2018 15:24:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 170BD213A2 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728958AbeJKWwG (ORCPT ); Thu, 11 Oct 2018 18:52:06 -0400 Received: from mga05.intel.com ([192.55.52.43]:3986 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728323AbeJKWsY (ORCPT ); Thu, 11 Oct 2018 18:48:24 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga105.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 11 Oct 2018 08:20:44 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.54,368,1534834800"; d="scan'208";a="78019110" Received: from 2b52.sc.intel.com ([143.183.136.147]) by fmsmga008.fm.intel.com with ESMTP; 11 Oct 2018 08:20:44 -0700 From: Yu-cheng Yu To: x86@kernel.org, "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , "H.J. Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , Randy Dunlap , "Ravi V. Shankar" , Vedvyas Shanbhogue Cc: Yu-cheng Yu Subject: [PATCH v5 10/27] mm/mmap: Prevent Shadow Stack VMA merges Date: Thu, 11 Oct 2018 08:15:06 -0700 Message-Id: <20181011151523.27101-11-yu-cheng.yu@intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20181011151523.27101-1-yu-cheng.yu@intel.com> References: <20181011151523.27101-1-yu-cheng.yu@intel.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org To prevent function call/return spills into the next shadow stack area, we do not merge shadow stack areas. Signed-off-by: Yu-cheng Yu --- mm/mmap.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/mm/mmap.c b/mm/mmap.c index 5f2b2b184c60..b85292014ec9 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1123,6 +1123,12 @@ struct vm_area_struct *vma_merge(struct mm_struct *mm, if (vm_flags & VM_SPECIAL) return NULL; + /* + * Do not merge shadow stack areas. + */ + if (vm_flags & VM_SHSTK) + return NULL; + if (prev) next = prev->vm_next; else -- 2.17.1