From: Hannes Frederic Sowa <hannes@stressinduktion•org>
To: Linus Torvalds <torvalds@linux-foundation•org>
Cc: "David Herrmann" <dh.herrmann@gmail•com>,
"Willy Tarreau" <w@1wt•eu>,
"David S. Miller" <davem@davemloft•net>,
netdev <netdev@vger•kernel.org>,
linux-kernel <linux-kernel@vger•kernel.org>,
"Eric Dumazet" <edumazet@google•com>,
"Марк Коренберг" <socketpair@gmail•com>,
"Tetsuo Handa" <penguin-kernel@i-love•sakura.ne.jp>,
"Simon McVittie" <simon.mcvittie@collabora•co.uk>
Subject: Re: [PATCH v2] unix: properly account for FDs passed over unix sockets
Date: Tue, 2 Feb 2016 21:56:36 +0100 [thread overview]
Message-ID: <56B11804.2050008@stressinduktion.org> (raw)
In-Reply-To: <CA+55aFz0CXGexEBmb8JU0+w7sFf3VfE3TpRzdj3aTiDxg2zDpg@mail.gmail.com>
On 02.02.2016 21:44, Linus Torvalds wrote:
> On Tue, Feb 2, 2016 at 12:32 PM, Hannes Frederic Sowa
> <hannes@stressinduktion•org> wrote:
>>
>> Unfortunately we never transfer a scm_cookie via the skbs but merely use it
>> to initialize unix_skb_parms structure in skb->cb and destroy it afterwards.
>
> Ok, I obviously didn't check very closely.
>
>> But "struct pid *" in unix_skb_parms should be enough to get us to
>> corresponding "struct cred *" so we can decrement the correct counter during
>> skb destruction.
>
> Umm. I think the "struct cred" may change in between, can't it?
While reviewing the task_struct->cred/real_cred assignments, I noticed
that, too. I already went the same way and added a "struct cred *" to
unix_skb_parms.
> So I don't think you can later look up the cred based on the pid.
Yep, it also looked to dangerous to me.
> Could we add the cred pointer (or just the user pointer) to the unix_skb_parms?
>
> Or maybe just add it to the "struct scm_fp_list"?
scm_fp_list seems to be an even better place. I have a look, thanks!
Hannes
next prev parent reply other threads:[~2016-02-02 20:56 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-10 6:58 [PATCH v2] unix: properly account for FDs passed over unix sockets Willy Tarreau
2016-01-11 5:05 ` David Miller
2016-02-02 17:34 ` David Herrmann
2016-02-02 18:29 ` Hannes Frederic Sowa
2016-02-02 19:29 ` Linus Torvalds
2016-02-02 20:32 ` Hannes Frederic Sowa
2016-02-02 20:39 ` Willy Tarreau
2016-02-02 21:55 ` Hannes Frederic Sowa
[not found] ` <CA+55aFzqdR80MKupCs+va8vtbTU67Jobax1QAbfWNktQCXFxpA@mail.gmail.com>
2016-02-03 0:57 ` Hannes Frederic Sowa
2016-02-03 1:12 ` Hannes Frederic Sowa
2016-02-02 20:44 ` Linus Torvalds
2016-02-02 20:49 ` Willy Tarreau
2016-02-02 20:53 ` Linus Torvalds
2016-02-02 20:58 ` Willy Tarreau
2016-02-02 20:56 ` Hannes Frederic Sowa [this message]
2016-02-03 12:19 ` David Laight
2016-02-03 11:36 ` Simon McVittie
2016-02-03 11:56 ` Hannes Frederic Sowa
2016-02-03 11:56 ` David Herrmann
2016-02-03 12:49 ` Simon McVittie
2016-02-03 14:07 ` Hannes Frederic Sowa
-- strict thread matches above, loose matches on Subject: below --
2016-01-10 6:58 Willy Tarreau
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