From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:38198 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759683AbdEWSi1 (ORCPT ); Tue, 23 May 2017 14:38:27 -0400 Subject: Patch "drivers: char: mem: Check for address space wraparound with mmap()" has been added to the 4.4-stable tree To: jwerner@chromium.org, gregkh@linuxfoundation.org Cc: , From: Date: Tue, 23 May 2017 20:37:29 +0200 Message-ID: <1495564649650@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled drivers: char: mem: Check for address space wraparound with mmap() to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: drivers-char-mem-check-for-address-space-wraparound-with-mmap.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From b299cde245b0b76c977f4291162cf668e087b408 Mon Sep 17 00:00:00 2001 From: Julius Werner Date: Fri, 12 May 2017 14:42:58 -0700 Subject: drivers: char: mem: Check for address space wraparound with mmap() From: Julius Werner commit b299cde245b0b76c977f4291162cf668e087b408 upstream. /dev/mem currently allows mmap() mappings that wrap around the end of the physical address space, which should probably be illegal. It circumvents the existing STRICT_DEVMEM permission check because the loop immediately terminates (as the start address is already higher than the end address). On the x86_64 architecture it will then cause a panic (from the BUG(start >= end) in arch/x86/mm/pat.c:reserve_memtype()). This patch adds an explicit check to make sure offset + size will not wrap around in the physical address type. Signed-off-by: Julius Werner Signed-off-by: Greg Kroah-Hartman --- drivers/char/mem.c | 5 +++++ 1 file changed, 5 insertions(+) --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -343,6 +343,11 @@ static const struct vm_operations_struct static int mmap_mem(struct file *file, struct vm_area_struct *vma) { size_t size = vma->vm_end - vma->vm_start; + phys_addr_t offset = (phys_addr_t)vma->vm_pgoff << PAGE_SHIFT; + + /* It's illegal to wrap around the end of the physical address space. */ + if (offset + (phys_addr_t)size < offset) + return -EINVAL; if (!valid_mmap_phys_addr_range(vma->vm_pgoff, size)) return -EINVAL; Patches currently in stable-queue which might be from jwerner@chromium.org are queue-4.4/drivers-char-mem-check-for-address-space-wraparound-with-mmap.patch