From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965543AbcKND2i (ORCPT ); Sun, 13 Nov 2016 22:28:38 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:45177 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753613AbcKNCFQ (ORCPT ); Sun, 13 Nov 2016 21:05:16 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Al Viro" , "Linus Torvalds" , "Al Viro" Date: Mon, 14 Nov 2016 00:14:20 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 296/346] fix minor infoleak in get_user_ex() In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.39-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Al Viro commit 1c109fabbd51863475cd12ac206bdd249aee35af upstream. get_user_ex(x, ptr) should zero x on failure. It's not a lot of a leak (at most we are leaking uninitialized 64bit value off the kernel stack, and in a fairly constrained situation, at that), but the fix is trivial, so... Signed-off-by: Al Viro [ This sat in different branch from the uaccess fixes since mid-August ] Signed-off-by: Linus Torvalds Signed-off-by: Ben Hutchings --- arch/x86/include/asm/uaccess.h | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -391,7 +391,11 @@ do { \ #define __get_user_asm_ex(x, addr, itype, rtype, ltype) \ asm volatile("1: mov"itype" %1,%"rtype"0\n" \ "2:\n" \ - _ASM_EXTABLE_EX(1b, 2b) \ + ".section .fixup,\"ax\"\n" \ + "3:xor"itype" %"rtype"0,%"rtype"0\n" \ + " jmp 2b\n" \ + ".previous\n" \ + _ASM_EXTABLE_EX(1b, 3b) \ : ltype(x) : "m" (__m(addr))) #define __put_user_nocheck(x, ptr, size) \