From: ebiederm@xmission•com (Eric W. Biederman)
To: dingtianhong <dingtianhong@huawei•com>
Cc: "David S. Miller" <davem@davemloft•net>,
Sven Joachim <svenjoac@gmx•de>,
Greg Kroah-Hartman <gregkh@linuxfoundation•org>,
<linux-kernel@vger•kernel.org>, <stable@vger•kernel.org>,
Eric Dumazet <edumazet@google•com>,
Andy Lutomirski <luto@amacapital•net>,
Karel Srot <ksrot@redhat•com>, <netdev@vger•kernel.org>,
Eric Dumazet <eric.dumazet@gmail•com>
Subject: Re: [PATCH 1/2] Revert "af_unix: dont send SCM_CREDENTIAL when dest socket is NULL"
Date: Thu, 04 Apr 2013 03:22:07 -0700 [thread overview]
Message-ID: <87r4iqegts.fsf@xmission.com> (raw)
In-Reply-To: <515D30F6.9010004@huawei.com> (dingtianhong@huawei.com's message of "Thu, 4 Apr 2013 15:51:18 +0800")
dingtianhong <dingtianhong@huawei•com> writes:
> On 2013/4/4 10:13, Eric W. Biederman wrote:
>>
>> This reverts commit 14134f6584212d585b310ce95428014b653dfaf6.
>>
>> The problem that the above patch was meant to address is that af_unix
>> messages are not being coallesced because we are sending unnecesarry
>> credentials. Not sending credentials in maybe_add_creds totally
>> breaks unconnected unix domain sockets that wish to send credentails
>> to other sockets.
>>
>
> thanks for check the question and make a fix solution, but I still doubt that if unconnected unix
> domain socket wish to send credentails to oher sockets, why dont set
> SOCK_PASSCRED on sock->flags, I think the user need to decide the param
> and shouldnt send creds by default way.
The big issue is the semantics are the receiver sets SOCK_PASSCRED when
they want to receive credentials. When transmitting packets from
unconnected or unaccepted sockets we don't know if the receiver has set
SOCK_PASSCRED so when in doubt transmit. Historically we always
tranmitted credentials.
Furthermore we have a real regression in udev that breaks systems, so
this patch must be reverted.
Eric
next prev parent reply other threads:[~2013-04-04 10:22 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20130402221104.163133110@linuxfoundation.org>
[not found] ` <20130402221116.307254752@linuxfoundation.org>
[not found] ` <87vc833kpf.fsf@turtle.gmx.de>
[not found] ` <87k3ojnosa.fsf@xmission.com>
[not found] ` <1365034777.13853.46.camel@edumazet-glaptop>
[not found] ` <1365035424.13853.48.camel@edumazet-glaptop>
[not found] ` <878v4zjei0.fsf@xmission.com>
2013-04-04 2:13 ` [PATCH 1/2] Revert "af_unix: dont send SCM_CREDENTIAL when dest socket is NULL" Eric W. Biederman
2013-04-04 2:14 ` [PATCH 2/2] af_unix: If we don't care about credentials coallesce all messages Eric W. Biederman
2013-04-04 3:28 ` [PATCH 3/2] scm: Stop passing struct cred Eric W. Biederman
2013-04-05 4:47 ` David Miller
2013-04-04 7:56 ` [PATCH 2/2] af_unix: If we don't care about credentials coallesce all messages dingtianhong
2013-04-04 10:36 ` Eric W. Biederman
2013-04-05 4:47 ` David Miller
2013-04-04 7:51 ` [PATCH 1/2] Revert "af_unix: dont send SCM_CREDENTIAL when dest socket is NULL" dingtianhong
2013-04-04 10:22 ` Eric W. Biederman [this message]
2013-04-05 4:47 ` David Miller
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87r4iqegts.fsf@xmission.com \
--to=ebiederm@xmission$(echo .)com \
--cc=davem@davemloft$(echo .)net \
--cc=dingtianhong@huawei$(echo .)com \
--cc=edumazet@google$(echo .)com \
--cc=eric.dumazet@gmail$(echo .)com \
--cc=gregkh@linuxfoundation$(echo .)org \
--cc=ksrot@redhat$(echo .)com \
--cc=linux-kernel@vger$(echo .)kernel.org \
--cc=luto@amacapital$(echo .)net \
--cc=netdev@vger$(echo .)kernel.org \
--cc=stable@vger$(echo .)kernel.org \
--cc=svenjoac@gmx$(echo .)de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox