From mboxrd@z Thu Jan 1 00:00:00 1970 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> References: <20180607143807.3611-1-yu-cheng.yu@intel.com> Return-path: In-Reply-To: <20180607143807.3611-1-yu-cheng.yu@intel.com> Sender: linux-kernel-owner@vger.kernel.org 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 List-Id: linux-arch.vger.kernel.org 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 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga09.intel.com ([134.134.136.24]:36346 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933773AbeFGOlh (ORCPT ); Thu, 7 Jun 2018 10:41:37 -0400 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: linux-arch-owner@vger.kernel.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 Message-ID: <20180607143807.BFCf6b1-F3XEPCbTBtIDeVv4TVMfmx2AzVelXXhLZ4A@z> 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