lkml.org 
[lkml]   [2014]   [Sep]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: For review: user_namespace(7) man page
On Tue, Sep 9, 2014 at 12:26 PM, Andy Lutomirski <luto@amacapital.net> wrote:
> On Tue, Sep 9, 2014 at 9:05 AM, Eric W. Biederman <ebiederm@xmission.com> wrote:
>>
>> We may also want to discuss the specific restrictions on chroot.
>>
>> The text about chroot at least gives people a strong hint that the
>> chroot rules are affected by user namespaces.
>>
>> The restrictions that we have settled on to avoid chroot being a problem
>> are the creator of a user namespace must not be chrooted in their
>> current mount namespace, and the creator of the user namespace must not
>> be threaded.
>>
>> Andy can you check me on this it looks like unshare is currently buggy
>> in that it will allow a threaded application to create a user namespace.
>
> I think it's this code in unshare:
>
> /*
> * If unsharing a user namespace must also unshare the thread.
> */
> if (unshare_flags & CLONE_NEWUSER)
> unshare_flags |= CLONE_THREAD | CLONE_FS;
>
> I suppose that this should be documented.
>
> CLONE_FS prevents the chroot from leaking out of the namespace. (But
> see the other thread that I'm about to start...)

Never mind. I thought I saw a bug, but I was wrong.

--Andy


\
 
 \ /
  Last update: 2014-09-09 22:21    [W:0.277 / U:1.392 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site