linux-kernel - Re: [PATCH -mm 1/2] user namespace : add unshare

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20070608122215.5da4fa87.akpm@linux-foundation.org>
Date:	Fri, 8 Jun 2007 12:22:15 -0700
From:	Andrew Morton <akpm@...ux-foundation.org>
To:	Cedric Le Goater <clg@...ibm.com>
Cc:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	"Serge E. Hallyn" <serue@...ibm.com>,
	Pavel Emelianov <xemul@...nvz.org>,
	Herbert Poetzl <herbert@...hfloor.at>,
	Kirill Korotaev <dev@...ru>,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	Linux Containers <containers@...ts.osdl.org>
Subject: Re: [PATCH -mm 1/2] user namespace : add unshare

On Fri, 08 Jun 2007 17:14:07 +0200
Cedric Le Goater <clg@...ibm.com> wrote:

> Basically, it will allow a process to unshare its user_struct table, resetting
> at the same time its own user_struct and all the associated accounting.
> 
> A new root user (uid == 0) is added to the user namespace upon creation.  Such
> root users have full privileges and it seems that theses privileges should be
> controlled through some means (process capabilities ?)

This second paragraph is distressingly indecisive.  How much thought has
gone into this??

For a start, it seems wrong for the kernel to hardwire knowledge about UID
0 in this fashion.

I'd have thought that a better model for user-namespace unsharing would be
to do a copy-by-value of the entire namespace, then permit a
suitably-privileged application to go through and kill off any unwanted
users from the now-unshared user namespace.

Or maybe just remove that "Insert new root user" altogether?  What would
then go wrong?

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/