From mboxrd@z Thu Jan 1 00:00:00 1970 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752582AbdBET1K (ORCPT + 2 others); Sun, 5 Feb 2017 14:27:10 -0500 Received: from wtarreau.pck.nerim.net ([62.212.114.60]:28354 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754435AbdBET1H (ORCPT ); Sun, 5 Feb 2017 14:27:07 -0500 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, linux@roeck-us.net Cc: Al Viro , Willy Tarreau Subject: [PATCH 3.10 082/319] asm-generic: make get_user() clear the destination on errors Date: Sun, 5 Feb 2017 20:21:09 +0100 Message-Id: <1486322486-8024-53-git-send-email-w@1wt.eu> X-Mailer: git-send-email 2.8.0.rc2.1.gbe9624a In-Reply-To: <1486322486-8024-1-git-send-email-w@1wt.eu> References: <1486322486-8024-1-git-send-email-w@1wt.eu> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: From: Al Viro commit 9ad18b75c2f6e4a78ce204e79f37781f8815c0fa upstream. both for access_ok() failures and for faults halfway through Signed-off-by: Al Viro Signed-off-by: Willy Tarreau --- include/asm-generic/uaccess.h | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/include/asm-generic/uaccess.h b/include/asm-generic/uaccess.h index c184aa8..fee282a 100644 --- a/include/asm-generic/uaccess.h +++ b/include/asm-generic/uaccess.h @@ -228,14 +228,18 @@ extern int __put_user_bad(void) __attribute__((noreturn)); might_sleep(); \ access_ok(VERIFY_READ, ptr, sizeof(*ptr)) ? \ __get_user(x, ptr) : \ - -EFAULT; \ + ((x) = (__typeof__(*(ptr)))0,-EFAULT); \ }) #ifndef __get_user_fn 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; } #define __get_user_fn(sz, u, k) __get_user_fn(sz, u, k) -- 2.8.0.rc2.1.gbe9624a