From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-f69.google.com (mail-pl0-f69.google.com [209.85.160.69]) by kanga.kvack.org (Postfix) with ESMTP id 287F16B028B for ; Thu, 7 Jun 2018 10:41:36 -0400 (EDT) Received: by mail-pl0-f69.google.com with SMTP id 31-v6so5521659plf.19 for ; Thu, 07 Jun 2018 07:41:36 -0700 (PDT) Received: from mga05.intel.com (mga05.intel.com. [192.55.52.43]) by mx.google.com with ESMTPS id i74-v6si8716254pgc.188.2018.06.07.07.41.35 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 07 Jun 2018 07:41:35 -0700 (PDT) From: Yu-cheng Yu Subject: [PATCH 09/10] mm: Prevent madvise from changing shadow stack Date: Thu, 7 Jun 2018 07:38:06 -0700 Message-Id: <20180607143807.3611-10-yu-cheng.yu@intel.com> In-Reply-To: <20180607143807.3611-1-yu-cheng.yu@intel.com> References: <20180607143807.3611-1-yu-cheng.yu@intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, x86@kernel.org, "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , "H.J. Lu" , Vedvyas Shanbhogue , "Ravi V. Shankar" , Dave Hansen , Andy Lutomirski , Jonathan Corbet , Oleg Nesterov , Arnd Bergmann , Mike Kravetz Cc: Yu-cheng Yu Signed-off-by: Yu-cheng Yu --- mm/madvise.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/mm/madvise.c b/mm/madvise.c index 4d3c922ea1a1..2a6988badd6b 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -839,6 +839,14 @@ SYSCALL_DEFINE3(madvise, unsigned long, start, size_t, len_in, int, behavior) if (vma && start > vma->vm_start) prev = vma; + /* + * Don't do anything on shadow stack. + */ + if (vma->vm_flags & VM_SHSTK) { + error = -EINVAL; + goto out_no_plug; + } + blk_start_plug(&plug); for (;;) { /* Still start < end. */ @@ -876,6 +884,7 @@ SYSCALL_DEFINE3(madvise, unsigned long, start, size_t, len_in, int, behavior) } out: blk_finish_plug(&plug); +out_no_plug: if (write) up_write(¤t->mm->mmap_sem); else -- 2.15.1