From: Andi Kleen <andi@firstfloor.org>
To: Shanker Wang <shanker@tuna.tsinghua.edu.cn>
Cc: netdev@vger.kernel.org,
Hannes Frederic Sowa <hannes@stressinduktion.org>,
Richard Weinberger <richard.weinberger@gmail.com>,
Guillaume Nault <g.nault@alphalink.fr>,
Miao Wang <shankerwangmiao@gmail.com>
Subject: Re: [PATCH] net:ppp: replace too strict capability restriction on opening /dev/ppp
Date: Sun, 19 Jun 2016 22:02:02 -0700 [thread overview]
Message-ID: <87wplkihbp.fsf@tassilo.jf.intel.com> (raw)
In-Reply-To: <44A9BDB8-754B-4402-BD09-6381229C07C5@tuna.tsinghua.edu.cn> (Shanker Wang's message of "Sun, 19 Jun 2016 01:38:55 +0200")
Shanker Wang <shanker@tuna.tsinghua.edu.cn> writes:
> This patch removes the check for CAP_NET_ADMIN in the initial namespace
> when opening /dev/open. Instead, CAP_NET_ADMIN is checked in the user
> namespace the net namespace was created so that /dev/ppp cat get opened
> in a unprivileged container.
Seems dangerous. From a quick look at the PPP ioctl there is no limit
how many PPP devices this can create. So a container having access to
this would be able to fill all kernel memory. Probably needs more
auditing and hardening first.
In general there seems to be a lot of attack surface for root
in PPP.
-Andi
--
ak@linux.intel.com -- Speaking for myself only
next prev parent reply other threads:[~2016-06-20 5:02 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-18 23:38 [PATCH] net:ppp: replace too strict capability restriction on opening /dev/ppp Shanker Wang
2016-06-20 5:02 ` Andi Kleen [this message]
2016-06-20 6:47 ` Richard Weinberger
-- strict thread matches above, loose matches on Subject: below --
2016-06-19 5:21 Shanker Wang
2016-06-19 5:24 ` David Miller
2016-06-19 5:31 ` Shanker Wang
2016-06-19 10:13 ` Richard Weinberger
2016-06-19 10:36 ` Shanker Wang
2016-06-19 10:40 ` Richard Weinberger
2016-07-16 9:41 ` Shanker Wang
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