From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f199.google.com (mail-pf0-f199.google.com [209.85.192.199]) by kanga.kvack.org (Postfix) with ESMTP id 0631E6B026B for ; Tue, 10 Jul 2018 18:31:16 -0400 (EDT) Received: by mail-pf0-f199.google.com with SMTP id t10-v6so14866976pfh.0 for ; Tue, 10 Jul 2018 15:31:15 -0700 (PDT) Received: from mga11.intel.com (mga11.intel.com. [192.55.52.93]) by mx.google.com with ESMTPS id 31-v6si17386340plz.217.2018.07.10.15.31.14 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 10 Jul 2018 15:31:14 -0700 (PDT) From: Yu-cheng Yu Subject: [RFC PATCH v2 15/27] mm/mprotect: Prevent mprotect from changing shadow stack Date: Tue, 10 Jul 2018 15:26:27 -0700 Message-Id: <20180710222639.8241-16-yu-cheng.yu@intel.com> In-Reply-To: <20180710222639.8241-1-yu-cheng.yu@intel.com> References: <20180710222639.8241-1-yu-cheng.yu@intel.com> Sender: owner-linux-mm@kvack.org List-ID: 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 , Florian Weimer , "H.J. Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , "Ravi V. Shankar" , Vedvyas Shanbhogue Cc: Yu-cheng Yu Signed-off-by: Yu-cheng Yu --- mm/mprotect.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/mm/mprotect.c b/mm/mprotect.c index 625608bc8962..128dcb880c12 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -446,6 +446,15 @@ static int do_mprotect_pkey(unsigned long start, size_t len, error = -ENOMEM; if (!vma) goto out; + + /* + * Do not allow changing shadow stack memory. + */ + if (vma->vm_flags & VM_SHSTK) { + error = -EINVAL; + goto out; + } + prev = vma->vm_prev; if (unlikely(grows & PROT_GROWSDOWN)) { if (vma->vm_start >= end) -- 2.17.1