netdev - Re: [PATCH 5/5] net: Use netlink_ns_capable to verify the permisions of netlink messages

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Message-ID: <20140522170505.64ef87a2@griffin>
Date:	Thu, 22 May 2014 17:05:05 +0200
From:	Jiri Benc <jbenc@...hat.com>
To:	Andy Lutomirski <luto@...capital.net>
Cc:	Linus Torvalds <torvalds@...ux-foundation.org>,
	David Miller <davem@...emloft.net>,
	"Jorge Boncompte [DTI2]" <jorge@...2.net>,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	Vivek Goyal <vgoyal@...hat.com>,
	Simo Sorce <ssorce@...hat.com>,
	"security@...nel.org" <security@...nel.org>,
	Network Development <netdev@...r.kernel.org>,
	"Serge E. Hallyn" <serge@...lyn.com>
Subject: Re: [PATCH 5/5] net: Use netlink_ns_capable to verify the
 permisions of netlink messages

On Wed, 7 May 2014 16:45:10 -0700, Andy Lutomirski wrote:
> It looks like Zebra is mucking with its effective set.  It creates the
> socket w/o effective caps, raises them to bind (no clue why), lowers
> them post-bind, then raises them again to sendto.  Presumably the new
> checks cause the sendto to fail b/c the socket()-time credentials were
> insufficient.
> 
> I don't see why it bound w/ elevated permissions, since I don't think
> this is important.  And it never connected at all.
> 
> Hence my suggestion that we check permissions at connect time instead
> of socket() time and that we just check send-time permissions on an
> unconnected socket.  Yes, this is awful.

AFAIK this is still unresolved and this seems to be the only solution
proposed so far that fixes the security problem and does not break
zebra. Or have I missed something and the conclusion is zebra needs to
be modified to comply with the changed semantics?

 Jiri

-- 
Jiri Benc
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