From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759368Ab3ICFYZ (ORCPT ); Tue, 3 Sep 2013 01:24:25 -0400 Received: from intranet.asianux.com ([58.214.24.6]:27154 "EHLO intranet.asianux.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753133Ab3ICFYY (ORCPT ); Tue, 3 Sep 2013 01:24:24 -0400 X-Spam-Score: -100.9 Message-ID: <52257248.9080508@asianux.com> Date: Tue, 03 Sep 2013 13:23:20 +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: Andrew Morton CC: "linux-kernel@vger.kernel.org" , Michael Kerrisk Subject: Re: [PATCH] kernel/groups.c: consider about NULL for 'group_info' in all related extern functions References: <5212DBFA.8030805@asianux.com> <5212DC65.9080702@asianux.com> In-Reply-To: <5212DC65.9080702@asianux.com> Content-Type: text/plain; charset=GB2312 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Maintainers: Please help check this patch, when you have time. If need a related test, please let me know, I should try (better to provide some suggestions for test). Thanks. On 08/20/2013 11:03 AM, Chen Gang wrote: > > If this patch is correct, also need modify the man page for the return > value of getgroups(). > > Thanks. > > On 08/20/2013 11:01 AM, Chen Gang wrote: >> groups_alloc() can return NULL for 'group_info', also group_search() >> already considers about NULL for 'group_info', so can assume the caller >> has right to use all related extern functions when 'group_info' is NULL. >> >> For groups_free(), need check NULL to match groups_alloc(), just like >> kmalloc/free(). >> >> For set_groups(), can allow the caller to set NULL parameter to new >> 'cred'. >> >> For system call getgroups(), if 'cred->group_info' is NULL, need return >> the related error code (no related data), also need change the related >> man page ("man 2 getgroups") to complete the return value. >> >> >> Signed-off-by: Chen Gang >> --- >> kernel/groups.c | 14 +++++++++++--- >> 1 files changed, 11 insertions(+), 3 deletions(-) >> >> diff --git a/kernel/groups.c b/kernel/groups.c >> index 6b2588d..a21a4ce 100644 >> --- a/kernel/groups.c >> +++ b/kernel/groups.c >> @@ -52,6 +52,9 @@ EXPORT_SYMBOL(groups_alloc); >> >> void groups_free(struct group_info *group_info) >> { >> + if (!group_info) >> + return; >> + >> if (group_info->blocks[0] != group_info->small_block) { >> int i; >> for (i = 0; i < group_info->nblocks; i++) >> @@ -163,9 +166,12 @@ int groups_search(const struct group_info >> *group_info, kgid_t grp) >> */ >> int set_groups(struct cred *new, struct group_info *group_info) >> { >> - put_group_info(new->group_info); >> - groups_sort(group_info); >> - get_group_info(group_info); >> + if (new->group_info) >> + put_group_info(new->group_info); >> + if (group_info) { >> + groups_sort(group_info); >> + get_group_info(group_info); >> + } >> new->group_info = group_info; >> return 0; >> } >> @@ -206,6 +212,8 @@ SYSCALL_DEFINE2(getgroups, int, gidsetsize, gid_t >> __user *, grouplist) >> >> if (gidsetsize < 0) >> return -EINVAL; >> + if (!cred->group_info) >> + return -ENODATA; >> >> /* no need to grab task_lock here; it cannot change */ >> i = cred->group_info->ngroups; >> > > -- Chen Gang