From: Florian Weimer <fw@deneb.enyo.de>
To: Karel Zak <kzak@redhat.com>
Cc: Stanislav Brabec <sbrabec@suse.cz>,
util-linux@vger.kernel.org,
Federico Bento <up201407890@alunos.dcc.fc.up.pt>,
Jiri Slaby <jslaby@suse.cz>
Subject: Re: Fixing su + runuser vulnerability CVE-2016-2779
Date: Sun, 09 Oct 2016 13:09:28 +0200 [thread overview]
Message-ID: <87wphhhj87.fsf@mid.deneb.enyo.de> (raw)
In-Reply-To: <20161003132918.lkgiqv2oejtuy6xo@ws.net.home> (Karel Zak's message of "Mon, 3 Oct 2016 15:29:18 +0200")
* Karel Zak:
> I have tried to send tty FD to another process by unix socket and the
> ioctl result is EPERM. See the test_tiocsti below. It seems only root
> can do it (try suid the test program).
>
> session A:
> ./test_tiocsti --receive
I think the recipient has to give up its controlling terminal, become
a session leader, and then reopen the passed terminal (from
/proc/self/fd, if it's not reachable from /dev/pts). This way, you
should be able to do away with the root requirement.
> session B:
> runuser -u kzak -- ./test_tiocsti --send
>
>> The ioctl should be fired in the hell... :-)
>
> This is still true.
The kernel implementation doesn't even do error checking. Surely it
can fail if there isn't enough memory in the destination buffer ...
next prev parent reply other threads:[~2016-10-09 11:09 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-02 19:35 Fixing su + runuser vulnerability CVE-2016-2779 Stanislav Brabec
2016-03-02 23:39 ` Ángel González
2016-03-03 0:37 ` up201407890
2016-03-03 16:21 ` Stanislav Brabec
2016-03-04 16:13 ` Stanislav Brabec
2016-03-04 18:03 ` up201407890
2016-03-04 23:50 ` Ángel González
2016-03-08 16:33 ` Stanislav Brabec
2016-03-07 13:13 ` Karel Zak
2016-03-08 16:02 ` Stanislav Brabec
2016-09-29 14:40 ` Karel Zak
2016-10-02 13:16 ` Florian Weimer
2016-10-03 10:28 ` Karel Zak
2016-10-03 13:29 ` Karel Zak
2016-10-09 11:09 ` Florian Weimer [this message]
2016-10-03 15:04 ` Karel Zak
2016-10-03 15:48 ` Pádraig Brady
2016-10-03 16:25 ` Karel Zak
2016-10-11 14:19 ` Karel Zak
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