From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f200.google.com (mail-pf0-f200.google.com [209.85.192.200]) by kanga.kvack.org (Postfix) with ESMTP id E73136B028F for ; Thu, 7 Jun 2018 10:41:36 -0400 (EDT) Received: by mail-pf0-f200.google.com with SMTP id j25-v6so3547146pfi.9 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 10/10] mm: Prevent munmap and remap_file_pages of shadow stack Date: Thu, 7 Jun 2018 07:38:07 -0700 Message-Id: <20180607143807.3611-11-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/mmap.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/mm/mmap.c b/mm/mmap.c index fc41c0543d7f..e7d1fcb7ec58 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2810,6 +2810,16 @@ EXPORT_SYMBOL(vm_munmap); SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len) { + struct vm_area_struct *vma; + + /* Do not munmap shadow stack */ + down_read(¤t->mm->mmap_sem); + vma = find_vma(current->mm, addr); + if (vma && (vma->vm_flags & VM_SHSTK)) { + up_read(¤t->mm->mmap_sem); + return -EINVAL; + } + up_read(¤t->mm->mmap_sem); profile_munmap(addr); return vm_munmap(addr, len); } @@ -2851,6 +2861,9 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size, if (!vma || !(vma->vm_flags & VM_SHARED)) goto out; + if (vma->vm_flags & VM_SHSTK) + goto out; + if (start < vma->vm_start) goto out; -- 2.15.1