From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751942Ab3HTCyv (ORCPT ); Mon, 19 Aug 2013 22:54:51 -0400 Received: from intranet.asianux.com ([58.214.24.6]:41383 "EHLO intranet.asianux.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751482Ab3HTCyu (ORCPT ); Mon, 19 Aug 2013 22:54:50 -0400 X-Spam-Score: -101.1 Message-ID: <5212DA37.1090101@asianux.com> Date: Tue, 20 Aug 2013 10:53:43 +0800 From: Chen Gang User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130110 Thunderbird/17.0.2 MIME-Version: 1.0 To: "Eric W. Biederman" , Serge Hallyn , Oleg Nesterov , Andy Lutomirski , "dhowells@redhat.com" CC: "linux-kernel@vger.kernel.org" Subject: [PATCH] kernel: user_namespace: always set the return parameter 'new_cred' when call unshare_userns() successfully. Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When unshare_userns() succeed, recommend to always set the return parameter which may be used by caller. The caller has rights to call it with 'new_cred' uninitialized, if succeed, the caller can assume the 'new_cred' has been initialized. Signed-off-by: Chen Gang --- include/linux/user_namespace.h | 1 + kernel/user_namespace.c | 4 +++- 2 files changed, 4 insertions(+), 1 deletions(-) diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h index b6b215f..3159af5 100644 --- a/include/linux/user_namespace.h +++ b/include/linux/user_namespace.h @@ -75,6 +75,7 @@ static inline int unshare_userns(unsigned long unshare_flags, { if (unshare_flags & CLONE_NEWUSER) return -EINVAL; + *new_cred = NULL; return 0; } diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c index 6e50a44..6b90818 100644 --- a/kernel/user_namespace.c +++ b/kernel/user_namespace.c @@ -107,8 +107,10 @@ int unshare_userns(unsigned long unshare_flags, struct cred **new_cred) struct cred *cred; int err = -ENOMEM; - if (!(unshare_flags & CLONE_NEWUSER)) + if (!(unshare_flags & CLONE_NEWUSER)) { + *new_cred = NULL; return 0; + } cred = prepare_creds(); if (cred) { -- 1.7.7.6