Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755497AbcKNCO0 (ORCPT ); Sun, 13 Nov 2016 21:14:26 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:46205 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754520AbcKNCGN (ORCPT ); Sun, 13 Nov 2016 21:06:13 -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" Date: Mon, 14 Nov 2016 00:14:07 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 106/152] asm-generic: make get_user() clear the destination on errors 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 Content-Length: 1161 Lines: 40 3.2.84-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Al Viro commit 9ad18b75c2f6e4a78ce204e79f37781f8815c0fa upstream. both for access_ok() failures and for faults halfway through Signed-off-by: Al Viro [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings --- include/asm-generic/uaccess.h | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) --- a/include/asm-generic/uaccess.h +++ b/include/asm-generic/uaccess.h @@ -221,13 +221,17 @@ extern int __put_user_bad(void) __attrib might_sleep(); \ access_ok(VERIFY_READ, ptr, sizeof(*ptr)) ? \ __get_user(x, ptr) : \ - -EFAULT; \ + ((x) = (__typeof__(*(ptr)))0,-EFAULT); \ }) static inline int __get_user_fn(size_t size, const void __user *ptr, void *x) { - size = __copy_from_user(x, ptr, size); - return size ? -EFAULT : size; + size_t n = __copy_from_user(x, ptr, size); + if (unlikely(n)) { + memset(x + (size - n), 0, n); + return -EFAULT; + } + return 0; } extern int __get_user_bad(void) __attribute__((noreturn));