From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:58142 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751971AbcKOTMQ (ORCPT ); Tue, 15 Nov 2016 14:12:16 -0500 Subject: Patch "swapfile: fix memory corruption via malformed swapfile" has been added to the 4.8-stable tree To: jann@thejh.net, akpm@linux-foundation.org, gregkh@linuxfoundation.org, hannes@cmpxchg.org, hughd@google.com, jmarchan@redhat.com, keescook@chromium.org, kirill.shutemov@linux.intel.com, torvalds@linux-foundation.org, vbabka@suse.cz Cc: , From: Date: Tue, 15 Nov 2016 20:10:19 +0100 Message-ID: <147923701917948@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 swapfile: fix memory corruption via malformed swapfile to the 4.8-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: swapfile-fix-memory-corruption-via-malformed-swapfile.patch and it can be found in the queue-4.8 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From dd111be69114cc867f8e826284559bfbc1c40e37 Mon Sep 17 00:00:00 2001 From: Jann Horn Date: Thu, 10 Nov 2016 10:46:19 -0800 Subject: swapfile: fix memory corruption via malformed swapfile From: Jann Horn commit dd111be69114cc867f8e826284559bfbc1c40e37 upstream. When root activates a swap partition whose header has the wrong endianness, nr_badpages elements of badpages are swabbed before nr_badpages has been checked, leading to a buffer overrun of up to 8GB. This normally is not a security issue because it can only be exploited by root (more specifically, a process with CAP_SYS_ADMIN or the ability to modify a swap file/partition), and such a process can already e.g. modify swapped-out memory of any other userspace process on the system. Link: http://lkml.kernel.org/r/1477949533-2509-1-git-send-email-jann@thejh.net Signed-off-by: Jann Horn Acked-by: Kees Cook Acked-by: Jerome Marchand Acked-by: Johannes Weiner Cc: "Kirill A. Shutemov" Cc: Vlastimil Babka Cc: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/swapfile.c | 2 ++ 1 file changed, 2 insertions(+) --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -2218,6 +2218,8 @@ static unsigned long read_swap_header(st swab32s(&swap_header->info.version); swab32s(&swap_header->info.last_page); swab32s(&swap_header->info.nr_badpages); + if (swap_header->info.nr_badpages > MAX_SWAP_BADPAGES) + return 0; for (i = 0; i < swap_header->info.nr_badpages; i++) swab32s(&swap_header->info.badpages[i]); } Patches currently in stable-queue which might be from jann@thejh.net are queue-4.8/swapfile-fix-memory-corruption-via-malformed-swapfile.patch