linux-kernel - [proc:] 3.16.0-10436-g9138475: access denied to /proc/1540/task/1540/net/dev

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Date:	Sun, 10 Aug 2014 19:25:11 +0200
From:	Jörg Otte <jrg.otte@...il.com>
To:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: [proc:] 3.16.0-10436-g9138475: access denied to /proc/1540/task/1540/net/dev

My network interface eth0 doesn't come up in 3.16.0-10436-g9138475
I am seeing following "security problem" in dmesg:

audit: type=1400 audit(1407684227.003:28): apparmor="DENIED"
  operation="open" profile="/sbin/dhclient"
  name="/proc/1540/task/1540/net/dev" pid=1540 comm="dhclient"
  requested_mask="r" denied_mask="r" fsuid=0 ouid=0

I think the problem is introduced by the following commits, especially
6ba8ed7:

344470c proc: Point /proc/mounts at /proc/thread-self/mounts instead
of /proc/self/mounts
e813244 proc: Point /proc/net at /proc/thread-self/net instead of /proc/self/net
0097875 proc: Implement /proc/thread-self to point at the directory of
the current thread
6ba8ed7 proc: Have net show up under /proc/<tgid>/task/<tid>

To get eth0 activated I need to MODIFY APPARMOR-CONFIGURATION:

e.g.
# Site-specific additions and overrides for sbin.dhclient.
# For more details, please see /etc/apparmor.d/local/README.
/sbin/dhclient {
  @{PROC}/[0-9]*/task/[0-9]*/net/ r,
  @{PROC}/[0-9]*/task/[0-9]*/net/** r
}

Is this interface change to user space intentional?

Thanks,
Jörg
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