Serge Hallyn [Tue, 17 Nov 2015 18:59:05 +0000 (12:59 -0600)]
Better handle preserve_ns behavior
Commit b6b2b194a8 preserves the container's namespaces for
possible later use in stop hook. But some kernels don't have
/proc/pid/ns/ns for all the namespaces we may be interested in.
So warn but continue if this is the case.
Implement stgraber's suggested semantics.
- User requests some namespaces be preserved:
- If /proc/self/ns is missing => fail (saying kernel misses setns)
- If /proc/self/ns/<namespace> entry is missing => fail (saying kernel misses setns for <namespace>)
- User doesn't request some namespaces be preserved:
- If /proc/self/ns is missing => log an INFO message (kernel misses setns) and continue
- If /proc/self/ns/<namespace> entry is missing => log an INFO message (kernel misses setns for <namespace>) and continue
Serge Hallyn [Wed, 11 Nov 2015 17:13:25 +0000 (17:13 +0000)]
clone: clear the rootfs out of unexpanded config
Closes #694
When we start cloning container c1 to c2, we first save c1's
configuration in c2's as a starting point. We long ago cleared
out the lxc.rootfs entry before saving it, so that if we are
killed before we update the rootfs, c2's rootfs doesn't point
to c1's. Because then lxc-destroy -n c2 would delete c1's rootfs.
But when we introduced the unexpanded_config, we didn't update
this code to clear the rootfs out of the unexpanded_config, which
is what now actually gets saved in write_config().
When we create a random container directory with mkdtemp() we set the mode to
0770 otherwise do_lxcapi_clone() will complain about not being able to create
the config.
Signed-off-by: Christian Brauner <christianvanbrauner@gmail.com> Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
When the clone failed we tried to destroy the container. This will lead to a
segfault. Instead simply return -1. Also move the call to free_mnts() after the
put label to free the user specified mounts even when we just goto put.
Signed-off-by: Christian Brauner <christianvanbrauner@gmail.com> Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
This is a complete reimplementation of lxc-clone and lxc-start-ephemeral.
lxc-copy merges the functionalities of lxc-clone + lxc-start-ephemeral.
(1) Cloning containers:
(a) as copy:
lxc-copy -n aa -N bb
(b) as snapshot:
lxc-copy -n aa -N bb -s
(2) Renaming containers:
lxc-copy -n aa -N bb -R
(3) Starting ephemeral containers:
Ephemeral containers are created and started by passing the flag -e /
--ephemeral. Whenever this flag is missing a copy of the container is created.
The flag -e / --ephemeral implies -s / --snapshot.
(a) start ephemeral container daemonized with random name:
lxc-copy -n aa -e
(b) start ephemeral container in foreground mode with random name:
lxc-copy -n aa -e -F
(c) start ephemeral container with specified name in daemonized mode:
Analogous to lxc-start ephemeral containers start in daemonized
mode per default:
lxc-copy -n aa -N bb -e
One can however also explicitly pass -d / --daemon:
lxc-copy -n aa -N bb -e -d
but both commands are equivalent.
(d) start non-ephemeral container in daemonized mode:
lxc-copy -n aa -D -e
(e) start ephemeral container in daemonized mode and keep the original
hostname:
lxc-copy -n aa -K -e
(f) start ephemeral container in daemonized mode and keep the
MAC-address of the original container:
lxc-copy -n aa -M -e
(g) start ephemeral container with custom mounts (additional mounts can
be of type {bind,aufs,overlay}) in daemonized mode:
lxc-copy -n aa -e -m bind=/src:/dest:ro,aufs=/src:/dest,overlay=/src:/dest
(4) Other options:
lxc-copy --help
In order to create a random containername and random upper- and workdirs for
custom mounts we use mkdtemp() to not just create the names but also directly
create the corresponding directories. This will be safer and make the code
considerably shorter.
Signed-off-by: Christian Brauner <christianvanbrauner@gmail.com> Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
Stéphane Graber [Thu, 12 Nov 2015 17:44:38 +0000 (12:44 -0500)]
ubuntu-cloud: Various fixes
- Update list of supported releases
- Make the fallback release trusty
- Don't specify the compression algorithm (use auto-detection) so that
people passing tarballs to the template don't see regressions.
Signed-off-by: Stéphane Graber <stgraber@ubuntu.com> Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
Virgil Dupras [Tue, 10 Nov 2015 02:23:51 +0000 (21:23 -0500)]
Fetch Debian archive GPG keyrings when they're not available
When running the debian template on a non-debian host, it's usual not to
have debian-archive-keyring.gpg. When that happens, we skip the
signature checking of the release, which is dangerous because it's made over
HTTP.
This commit adds automatic fetching of Debian release keys.
Tycho Andersen [Sat, 7 Nov 2015 00:26:43 +0000 (17:26 -0700)]
c/r: use freezer to seize tasks
Instead of relying on the old ptrace loop, we should instead put all the
tasks in the container into the freezer. This will stop them all at the
same time, preventing fork bombs from causing criu to infinite loop (and is
also simply a lot faster).
Note that this uses --freeze-cgroup which isn't in criu 1.7, so it should
only go into master.
Tycho Andersen [Fri, 6 Nov 2015 20:50:33 +0000 (13:50 -0700)]
define PR_SET_MM_MAP & friends if necessary
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.
Tycho Andersen [Fri, 6 Nov 2015 19:34:47 +0000 (12:34 -0700)]
use PR_SET_MM_MAP instead of PR_SET_MM
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>
(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:
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>
Jakub Sztandera [Fri, 30 Oct 2015 11:05:44 +0000 (12:05 +0100)]
arch template: Fix systemd-sysctl service
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.
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
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>
Serge Hallyn [Thu, 15 Oct 2015 18:56:17 +0000 (18:56 +0000)]
Ignore trailing /init.scope in init cgroups
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.
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>
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.:
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.)
Serge Hallyn [Sat, 3 Oct 2015 21:52:16 +0000 (21:52 +0000)]
lxc_mount_auto_mounts: fix weirdness
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.
While lxc-copy is under review let users benefit (reboot survival etc.) from the
new lxc.ephemeral option already in lxc-start-ephemeral. This way we can remove
the lxc.hook.post-stop script-
Signed-off-by: Christian Brauner <christianvanbrauner@gmail.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>
Colin Watson [Wed, 30 Sep 2015 12:37:10 +0000 (13:37 +0100)]
lxc-start-ephemeral: Parse passwd directly
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.
Serge Hallyn [Mon, 31 Aug 2015 17:57:20 +0000 (12:57 -0500)]
CVE-2015-1335: Protect container mounts against symlinks
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.
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.
Otherwise the kernel will umount when it gets around to it, but
that on lxc_destroy we may race with it and fail the rmdir of
the overmounted (BUSY) rootfs.
On shutdown ephemeral containers will be destroyed. We use mod_all_rdeps() from
lxccontainer.c to update the lxc_snapshots file of the original container. We
also include lxclock.h to lock the container when mod_all_rdeps() is called to
avoid races.
Signed-off-by: Christian Brauner <christianvanbrauner@gmail.com> Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
This allows us to use standard string handling functions and we can avoid using
the GNU-extension memmem(). This simplifies removing the container from the
lxc_snapshots file. Wrap strstr() in a while loop to remove duplicate entries.
Signed-off-by: Christian Brauner <christianvanbrauner@gmail.com> Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
projects / thirdparty / lxc.git / log
