PR_SET_MM_MAP only went in to the kernel at 3.18 (or 3.19), so we need to
define these for kernels before then. If there was an error, the code
simply logs the failure and continues on.

Also, we can drop the PR_SET_MM_otherstuff contstants since those were
dropped in 93525c00.
Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>

veths can be unconnected in the container's config, and we should handle
this case.
Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>

PR_SET_MM_MAP can be called as non-root, which we are in the unprivileged
(or nested) case.

Also, let's not do the strcpy() for the new cmdline until after we're sure
the prctl succeeded. This means that even if it does fail, we won't
mutilate the command line like we did before, it just won't be as pretty.

v2: remember to chop off bits of the string that are too long
Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>

Changes v3:
(1) Fix typo (q --> p).

(1) This commit fixes the calculations when updating paths in lxc.hooks.*
    entries. We now also update conf->unexpandend_alloced which hasn't been
done prior to this commit.

(2) Also we use the stricter check:

    	if (p >= lend)
    		continue;

    This should deal better with invalid config files.

(3) Insert some spaces between operators to increase readability.

(4) Use gotos to simplify function and increase readability.
Signed-off-by: Christian Brauner <christianvanbrauner@gmail.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>

When using overlay and aufs mounts with lxc.mount.entry users have to specify
absolute paths for upperdir and workdir which will then get created
automatically by mount_entry_create_overlay_dirs() and
mount_entry_create_aufs_dirs() in conf.c. When we clone a container with
overlay or aufs lxc.mount.entry entries we need to update these absolute paths.
In order to do this we add the function update_ovl_paths() in
lxccontainer.c. The function updates the mounts in two locations:

        1) lxc_conf->mount_list

and

        2) lxc_conf->unexpanded_config (by calling clone_update_unexp_ovl_dir())

If we were to only update 2) we would end up with wrong upperdir and workdir
mounts as the absolute paths would still point to the container that serves as
the base for the clone. If we were to only update 1) we would end up with wrong
upperdir and workdir lxc.mount.entry entries in the clone's config as the
absolute paths in upperdir and workdir would still point to the container that
serves as the base for the clone. Updating both will get the job done.

NOTE: This function does not sanitize paths apart from removing trailing
slashes. (So when a user specifies //home//someone/// it will be cleaned to
//home//someone. This is the minimal path cleansing which is also done by
lxc_container_new().) But the mount_entry_create_overlay_dirs() and
mount_entry_create_aufs_dirs() functions both try to be extremely strict about
when to create upperdirs and workdirs. They will only accept sanitized paths,
i.e. they require /home/someone. I think this is a (safety) virtue and we
should consider sanitizing paths in general. In short: update_ovl_paths() does
update all absolute paths to the new container but
mount_entry_create_overlay_dirs() and mount_entry_create_aufs_dirs() will still
refuse to create upperdir and workdir when the updated path is unclean. This
happens easily when e.g. a user calls lxc-clone -o OLD -n NEW -P
//home//chb///.
Signed-off-by: Christian Brauner <christianvanbrauner@gmail.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>

This functions updates absolute paths for overlay upper- and workdirs so users
can simply clone and start new containers without worrying about absolute paths
in lxc.mount.entry overlay entries.
Signed-off-by: Christian Brauner <christianvanbrauner@gmail.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>

Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>

Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>

The systemd-sysctl service includes condition that /proc/sys/ has to be read-write.
In lxc only /proc/sys/net/ is read-write which causes the condition to fail and service not to run.
This patch changes the check to /proc/sys/net/ and makes the service apply only rules that are in net tree.
Signed-off-by: Jakub Sztandera <kubuxu@gmail.com>

We didn't do it before, and it makes testcases fail.
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>

Instead of duplicating the cleanup-code, once for success and once for failure,
simply keep a variable fret which is -1 in the beginning and gets set to 0 on
success or stays -1 on failure.
Signed-off-by: Christian Brauner <christianvanbrauner@gmail.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>

The mount_entry_overlay_dirs() and mount_entry_aufs_dirs() functions create
workdirs and upperdirs for overlay and aufs lxc.mount.entry entries. They try
to make sure that the workdirs and upperdirs can only be created under the
containerdir (e.g. /path/to/the/container/CONTAINERNAME). In order to do this
the right hand side of

                if ((strncmp(upperdir, lxcpath, dirlen) == 0) && (strncmp(upperdir, rootfs->path, rootfslen) != 0))

was thought to check if the rootfs->path is not present in the workdir and
upperdir mount options. But the current check is bogus since it will be
trivially true whenever the container is a block-dev or overlay or aufs backed
since the rootfs->path will then have a form like e.g.

        overlayfs:/some/path:/some/other/path

This patch adds the function ovl_get_rootfs_dir() which parses rootfs->path by
searching backwards for the first occurrence of the delimiter pair ":/". We do
not simply search for ":" since it might be used in path names. If ":/" is not
found we assume the container is directory backed and simply return
strdup(rootfs->path).
Signed-off-by: Christian Brauner <christianvanbrauner@gmail.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>

Otherwise it may start too early and end up taking 10.0.3.1 even
though eth0 was eventually going to end up on 10.0.3.x.

https://bugs.launchpad.net/juju-core/+bug/1510619Reported-by: Ryan Harper <ryan.harper@ubuntu.com>
Cc: Martin Pitt <martin.pitt@ubuntu.com>
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>

lxc-usernsexec was using fd 0 and reopening it as 0,1,2 for
the new task.  If doing "lxc-usernsexec .. < script" this
will corrupt the file 'script'.
Reported-by: Fiedler Roman <Roman.Fiedler@ait.ac.at>
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>

The lxc monitor does not store the container's cgroups, rather it
recalculates them whenever needed.

Systemd moves itself into a /init.scope cgroup for the systemd
controller.

It might be worth changing that (by storing all cgroup info in the
lxc_handler), but for now go the hacky route and chop off any
trailing /init.scope.

I definately thinkg we want to switch to storing as that will be
more bullet-proof, but for now we need a quick backportable fix
for systemd 226 guests.
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>

Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>

The mount_entry_create_*_dirs() functions currently assume that the rootfs of
the container is actually named "rootfs". This has the consequence that

	del = strstr(lxcpath, "/rootfs");
	if (!del) {
		free(lxcpath);
		lxc_free_array((void **)opts, free);
		return -1;
	}
	*del = '\0';

will return NULL when the rootfs of a container is not actually named "rootfs".
This means the we return -1 and do not create the necessary upperdir/workdir
directories required for the overlay/aufs mount to work. Hence, let's not make
that assumption. We now pass lxc_path and lxc_name to
mount_entry_create_*_dirs() and create the path directly. To prevent failure we
also have mount_entry_create_*_dirs() check that lxc_name and lxc_path are not
empty when they are passed in.
Signed-off-by: Christian Brauner <christianvanbrauner@gmail.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>

Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>

Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>

When users wanted to mount overlay directories with lxc.mount.entry they had to
create upperdirs and workdirs beforehand in order to mount them. To create it
for them we add the functions mount_entry_create_overlay_dirs() and
mount_entry_create_aufs_dirs() which do this for them. User can now simply
specify e.g.:

        lxc.mount.entry = /lower merged overlay lowerdir=/lower,upper=/upper,workdir=/workdir,create=dir

and /upper and /workdir will be created for them. /upper and /workdir need to
be absolute paths to directories which are created under the containerdir (e.g.
under $lxcpath/CONTAINERNAME/). Relative mountpoints, mountpoints outside the
containerdir, and mountpoints within the container's rootfs are ignored. (The
latter *might* change in the future should it be considered safe/useful.)

Specifying

        lxc.mount.entry = /lower merged overlay lowerdir=/lower:/lower2,create=dir

will lead to a read-only overlay mount in accordance with the
kernel-documentation.

Specifying

        lxc.mount.entry = /lower merged overlay lowerdir=/lower,create=dir

will fail when no upperdir and workdir options are given.
Signed-off-by: Christian Brauner <christianvanbrauner@gmail.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>

Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>

Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>

The default_mounts[i].destination is never NULL except in the last
'stop here' entry.  Coverity doesn't know about that and so is spewing
a warning.  In any case, let's add a more stringent check in case someone
accidentally adds a NULL there later.
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>

This would have caught the regression last night.
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>

Enable aarch64 seccomp support for LXC containers running on ARM64
architectures. Tested with libseccomp 2.2.0 and the default seccomp
policy example files delivered with the LXC package.
Signed-off-by: Bogdan Purcareata <bogdan.purcareata@freescale.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>

On Ubuntu 15.04, lxc-start-ephemeral's call to pwd.getpwnam always
fails.  While I haven't been able to prove it or track down an exact
cause, I strongly suspect that glibc does not guarantee that you can
call NSS functions after a context switch without re-execing.  (Running
"id root" in a subprocess from the same point works fine.)

It's safer to use getent to extract the relevant line from the passwd
file and parse it directly.
Signed-off-by: Colin Watson <cjwatson@ubuntu.com>

Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>

Signed-off-by: Kaarle Ritvanen <kaarle.ritvanen@datakunkku.fi>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>

Signed-off-by: Kaarle Ritvanen <kaarle.ritvanen@datakunkku.fi>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>

Signed-off-by: Christian Brauner <christianvanbrauner@gmail.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>

CAP_BLOCK_SUSPEND (since Linux 3.5)
    Employ features that can block system suspend (epoll(7) EPOLLWAKEUP, /proc/sys/wake_lock).
Signed-off-by: Christian Brauner <christianvanbrauner@gmail.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>

CAP_AUDIT_READ (since Linux 3.16)
    Allow reading the audit log via a multicast netlink socket.
Signed-off-by: Christian Brauner <christianvanbrauner@gmail.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>

Signed-off-by: Christian Brauner <christianvanbrauner@gmail.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>

The dpkg architecture isn't relevant to LXC, only the kernel arch is.
Signed-off-by: Gergely Szasz <szaszg@hu.inter.net>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>

Don't proceed to try the mount if we failed to create the
target if it didn't exist.
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>

When a container starts up, lxc sets up the container's inital fstree
by doing a bunch of mounting, guided by the container configuration
file.  The container config is owned by the admin or user on the host,
so we do not try to guard against bad entries.  However, since the
mount target is in the container, it's possible that the container admin
could divert the mount with symbolic links.  This could bypass proper
container startup (i.e. confinement of a root-owned container by the
restrictive apparmor policy, by diverting the required write to
/proc/self/attr/current), or bypass the (path-based) apparmor policy
by diverting, say, /proc to /mnt in the container.

To prevent this,

1. do not allow mounts to paths containing symbolic links

2. do not allow bind mounts from relative paths containing symbolic
links.

Details:

Define safe_mount which ensures that the container has not inserted any
symbolic links into any mount targets for mounts to be done during
container setup.

The host's mount path may contain symbolic links.  As it is under the
control of the administrator, that's ok.  So safe_mount begins the check
for symbolic links after the rootfs->mount, by opening that directory.

It opens each directory along the path using openat() relative to the
parent directory using O_NOFOLLOW.  When the target is reached, it
mounts onto /proc/self/fd/<targetfd>.

Use safe_mount() in mount_entry(), when mounting container proc,
and when needed.  In particular, safe_mount() need not be used in
any case where:

1. the mount is done in the container's namespace
2. the mount is for the container's rootfs
3. the mount is relative to a tmpfs or proc/sysfs which we have
   just safe_mount()ed ourselves

Since we were using proc/net as a temporary placeholder for /proc/sys/net
during container startup, and proc/net is a symbolic link, use proc/tty
instead.

Update the lxc.container.conf manpage with details about the new
restrictions.

Finally, add a testcase to test some symbolic link possibilities.

Reported-by: Roman Fiedler
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>

Since we want to use null-terminated abstract sockets, let's compute the length
of them correctly.
Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>

systemd wants it.  It doesn't seem to be a big deal, but it's
one fewer error msg.
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>

I've noticed that a bunch of the code we've included over the past few
weeks has been using 8-spaces rather than tabs, making it all very hard
to read depending on your tabstop setting.

This commit attempts to revert all of that back to proper tabs and fix a
few more cases I've noticed here and there.

No functional changes are included in this commit.
Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>