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From: ebiederm@xmission.com (Eric W. Biederman)
To: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	containers@lists.linux-foundation.org,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Andy Lutomirski <luto@amacapital.net>,
	linux-security-module@vger.kernel.org
Subject: Re: [RFC][PATCH] Fix cap_capable to only allow owners in the parent user namespace to have caps.
Date: Fri, 14 Dec 2012 14:32:12 -0800	[thread overview]
Message-ID: <87bodww9hv.fsf@xmission.com> (raw)
In-Reply-To: <20121214202921.GA11450@mail.hallyn.com> (Serge E. Hallyn's message of "Fri, 14 Dec 2012 20:29:21 +0000")

"Serge E. Hallyn" <serge@hallyn.com> writes:

> Quoting Eric W. Biederman (ebiederm@xmission.com):

>> A child user namespace having capabilities against processes in it's
>> parent seems totally bizarre and pretty dangerous from a capabilities
>> standpoint.
>
> How would it have them against its parent?

init_user_ns
   userns a --- created by kuid 1
     userns b -- created by kuid 2
        process c in userns b with kuid 1

Serge read the first permisison check in common_cap. 
Think what happens in the above example.

For the rest I understand your concern.

Serge please read and look at the patches I have posted to fix
the issues Andy found with the user namespace tree.  Especially
the fix to commit_creds.

After you have looked at the patches to fix the issues I will
be happy to discuss things further with you.

Eric


  reply	other threads:[~2012-12-14 22:32 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-12-11 21:17 [GIT PULL] user namespace and namespace infrastructure changes for 3.8 Eric W. Biederman
2012-12-13 19:24 ` Andy Lutomirski
2012-12-13 22:01   ` Eric W. Biederman
2012-12-13 22:39     ` [RFC][PATCH] Fix cap_capable to only allow owners in the parent user namespace to have caps Eric W. Biederman
2012-12-13 22:43       ` Linus Torvalds
2012-12-13 22:55         ` Eric W. Biederman
2012-12-13 23:21       ` Andy Lutomirski
2012-12-14  2:33         ` Eric W. Biederman
2012-12-14  2:36           ` Andy Lutomirski
2012-12-14  3:20             ` [PATCH] " Eric W. Biederman
2012-12-14  3:28       ` [RFC][PATCH] " Serge E. Hallyn
2012-12-14  3:32         ` Eric W. Biederman
2012-12-14 15:26           ` Serge E. Hallyn
2012-12-14 15:47             ` Eric W. Biederman
2012-12-14 16:15               ` Serge E. Hallyn
2012-12-14 18:12                 ` Eric W. Biederman
2012-12-14 18:43                   ` Linus Torvalds
2012-12-14 18:47                     ` Andy Lutomirski
2012-12-14 20:50                     ` Serge E. Hallyn
2012-12-14 21:43                     ` Eric W. Biederman
2012-12-14 20:29                   ` Serge E. Hallyn
2012-12-14 22:32                     ` Eric W. Biederman [this message]
2012-12-15  0:14                       ` Serge E. Hallyn
2012-12-13 23:02     ` [GIT PULL] user namespace and namespace infrastructure changes for 3.8 Andy Lutomirski
2012-12-14  4:11       ` Eric W. Biederman
2012-12-14  5:34         ` Andy Lutomirski
2012-12-14 17:48           ` Eric W. Biederman

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