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  1. 15 Jan, 2013 4 commits
    • Implement userid mappings (enable user namespaces) · f6d3e3e4
      Serge Hallyn authored 
      The 3.8 kernel now supporst uid mappings, so I believe it's appropriate
to proceed with this patchset.
The container config supports new entries of the form:
 lxc.id_map = U 100000 0 10000
 lxc.id_map = G 100000 0 10000
meaning map 'virtual' uids (in the container) 0-10000 to uids
100000-110000 on the host, and same for gids.  So long as there are
mappings specified in the container config, then CONFIG_NEWUSER will
be used when the container is cloned.  This means that container
setup is no longer done with root privilege on the host, only root
privilege in the container.  Therefore cgroup setup is moved from the
init task to the monitor task.

To use this patchset, you currently need to either use the raring
kernel at ppa:serge-hallyn/usern-natty, or build your own kernel
from either git://kernel.ubuntu.com/serge/quantal-userns.git.
(Alternatively you can use Eric's tree at the latest userns-always-map-*
branch at
git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace.git
but you will likely want to at least enable tmpfs mounts in user namespaces)

You also need to chown the files in the container rootfs into the
mapped range.  There is a utility at
https://code.launchpad.net/~serge-hallyn/+junk/nsexec to do this.
uidmapshift does the chowning, while the container-userns-convert
script nicely wraps that program.  So I simply

	sudo lxc-create -t ubuntu -n r1
	sudo container-userns-convert r1 200000

will create a container which is shifted so uid 0 in the container
is uid 200000 on the host.

TODO: when doing setuid(0), need to only do that if 0 is one of the
ids we map to.  Similarly, when dropping capabilities, need to only
not do that if 0 is one of the ids we map to.  However, the question
of what to do for 'weird' containers in private user namespaces is
one I'm punting for later.
Signed-off-by: 's avatarSerge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: 's avatarStéphane Graber <stgraber@ubuntu.com>
    • setup cgroups from parent · 544a48a0
      Serge Hallyn authored 
      This is a first step to enabling user namespaces.  When starting a
container in a new user namespace, the child will not have the
rights to write to the cgroup fs.  (We can give it that right, but
don't always want to have to).

At the parent, we don't want to setup_cgroups() before the child
has set itself up.  But we also don't want to wait until it has
started running it's init, since that is racy.

Therefore introduce a new sync point.  The child will let the
parent know when it is ready to be confined, and wait for the
parent to respond that it has done so.  Then the child will finish
constraining itself with LSM and seccomp and execute init.
Signed-off-by: 's avatarSerge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: 's avatarStéphane Graber <stgraber@ubuntu.com>
    • clean up syncs · c4ea60df
      Serge Hallyn authored 
      Always unblock parent when child setup fails, rather than just
exiting.

Also remove a duplicate call to setup_cgroup().  We'll want it
close to there for userns, but not right there - that's too late,
and could happen after container init has done something bad
without cgroup restrictions.
Signed-off-by: 's avatarSerge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: 's avatarStéphane Graber <stgraber@ubuntu.com>
    • Multiple IP addresses: add them in the correct order · 8538f388
      Christian Seiler authored 
      Make sure that when configuring containers that have interfaces containing
multiple IP addresses they are added in the order of the configuration file
(i.e. the first being the primary one) and not the reverse order.
Signed-off-by: 's avatarChristian Seiler <christian@iwakd.de>
Acked-by: 's avatarSerge E. Hallyn <serge.hallyn@ubuntu.com>
Acked-by: 's avatarStéphane Graber <stgraber@ubuntu.com>
  3. 14 Jan, 2013 2 commits
    • MAKEDEV call, add autodev hooks, add environment variables for hook scripts. · f7bee6c6
      Michael H. Warfield authored 
      Ok...  Here's the patch again.  Since Serge is removing the loglevel
structure member, this patch no longer references that element.

From the original description:

1) Removes run_makedev() and the call to it from conf.c per discussion.

2) Adds an lxc.hook.autodev hook.

Note: This hook is very close (one routine level abstracted) from where
the run_makedev was called.  Anyone really rrreeeaaalllyyy needing
MAKEDEV can add it in with a small shim script to do whatever they want
under whatever distro they're using, so no functionality is lost there.

3) Added a number of environment variables for all the hook scripts to
reference to assist in execution.  Things like LXC_ROOTFS_MOUNT could be
very useful but others were added as well.  Room for more if anyone has
an itch.  All in one spot in lxc_start.c.

4) clearenv and putenv( "container=lxc" ) calls were moved to just after
the "start" hook in the container just prior to actually firing up the
container so we could use environment variables prior to that and have
them flushed them before firing up init.  Nice side effect is that you
can define environment variables and then call lxc-start and have them
show up in those hooks scripts.

5) I actually DID update the man page for lxc.conf!  I guess I lied when
I said I wouldn't get that done.

[... and ...]

I added the rcfile to the lxc_conf structure as suggested and moved the
setenv bundle from lxc-start.c over to start.c just prior to calling
run_lxc_hooks for the pre-start hook.
Signed-off-by: 's avatarMichael H. Warfield <mhw@WittsEnd.com>
Signed-off-by: 's avatarSerge Hallyn <serge.hallyn@ubuntu.com>
    • remove logfile and loglevel from struct lxc_conf · 9ea87d5d
      Serge Hallyn authored 
      The options are still supported in the lxc configuration file.
However they are stored only in local variables in src/lxc/log.c,
which can be read using two new functions:
	int lxc_log_get_level(void);
	const char *lxc_log_get_file(void);

Changelog: jan 14:
 have lxc_log_init use lxc_log_set_file(), have lxc_log_set_file() take
 a const char *, and have it keep its own strdup'd copy of the filename.
Signed-off-by: 's avatarSerge Hallyn <serge.hallyn@ubuntu.com>
  5. 13 Jan, 2013 1 commit
  7. 11 Jan, 2013 7 commits
  9. 10 Jan, 2013 2 commits
  11. 09 Jan, 2013 24 commits