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From: dingtianhong <dingtianhong@huawei.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>, <netdev@vger.kernel.org>,
	Li Zefan <lizefan@huawei.com>, Xinwei Hu <huxinwei@huawei.com>
Subject: Re: [Eulerkernel] [PATCH] af_unix: dont send SCM_CREDENTIAL when dest socket is NULL
Date: Tue, 26 Mar 2013 11:08:56 +0800	[thread overview]
Message-ID: <51511148.4000804@huawei.com> (raw)
In-Reply-To: <1364220269.29473.13.camel@edumazet-glaptop>

On 2013/3/25 22:04, Eric Dumazet wrote:
> On Mon, 2013-03-25 at 18:28 +0800, dingtianhong wrote:
>> SCM_SCREDENTIALS should apply to write() syscalls only either source or destination
>> socket asserted SOCK_PASSCRED. The original implememtation in maybe_add_creds is wrong,
>> and breaks several LSB testcases ( i.e. /tset/LSB.os/netowkr/recvfrom/T.recvfrom).
>>
>> Origionally-authored-by: Karel Srot <ksrot@redhat.com>
>> Signed-off-by: Ding Tianhong <dingtianhong@huawei.com>
>> ---
>>    net/unix/af_unix.c | 4 ++--
>>    1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
>> index 51be64f..99189fd 100644
>> --- a/net/unix/af_unix.c
>> +++ b/net/unix/af_unix.c
>> @@ -1413,8 +1413,8 @@ static void maybe_add_creds(struct sk_buff *skb, const struct socket *sock,
>>           if (UNIXCB(skb).cred)
>>                   return;
>>           if (test_bit(SOCK_PASSCRED, &sock->flags) ||
>> -           !other->sk_socket ||
>> -           test_bit(SOCK_PASSCRED, &other->sk_socket->flags)) {
>> +           (other->sk_socket &&
>> +           test_bit(SOCK_PASSCRED, &other->sk_socket->flags))) {
>>                   UNIXCB(skb).pid  = get_pid(task_tgid(current));
>>                   UNIXCB(skb).cred = get_current_cred();
>>           }
> 
> I am not sure why adding credentials if other->sk_socket is NULL could
> break an application ?
The bugzilla has report the bug:https://lsbbugs.linuxfoundation.org/show_bug.cgi?id=3523

> 
> This was the case before commit introducing this code.

The commit 16e5726269(af_unix: dont send SCM_CREDENTIALS by default) may  introducing the problem.

> 
> Anyway patch looks fine
> 
> Acked-by: Eric Dumazet <edumazet@google.com>
> 
> 
> 
> 
> 
> 

  parent reply	other threads:[~2013-03-26  3:09 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-03-25 10:28 [Eulerkernel] [PATCH] af_unix: dont send SCM_CREDENTIAL when dest socket is NULL dingtianhong
2013-03-25 14:04 ` Eric Dumazet
2013-03-25 17:12   ` David Miller
2013-03-26  3:08   ` dingtianhong [this message]
2013-03-26  4:32     ` Eric Dumazet
2013-03-26 11:35       ` dingtianhong
2013-03-26 13:46         ` Eric Dumazet
2013-03-27  7:35           ` dingtianhong

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