seccomp: warn but continue on unresolvable syscalls

If a syscall is listed which is not resolvable, continue.  This allows
us to keep a more complete list of syscalls in a global seccomp policy
without having to worry about older kernels not supporting the newer
syscalls.

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>
Fix typo in lxc_attach's usage

Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>
don't force dropping capabilities in lxc-init

Commit 0af683cf added clearing of capabilities to lxc-init, but only
after lxc_setup_fs() was done, likely so that the mounting done in
that routine wouldn't fail.

However, in my testing lxc_caps_reset() wasn't really effective
anyway since it did not clear the bounding set. Adding prctl
PR_CAPBSET_DROP in a loop from 0 to CAP_LAST_CAP would fix this, but I
don't think its necessary to forcefully clear all capabilities since
users can now specify lxc.cap.keep = none to drop all capabilities.

Signed-off-by: Dwight Engen <dwight.engen@oracle.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
split -lcap and -lselinux out of LIBS

Signed-off-by: Dwight Engen <dwight.engen@oracle.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
fix the expansion of libexecdir when not explicitly passed to configure

Signed-off-by: Dwight Engen <dwight.engen@oracle.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>
seccomp: support 'all' arch sections (plus bugfixes)

seccomp_ctx is already a void*, so don't use 'scmp_filter_ctx *'

Separately track the native arch from the arch a rule is aimed at.

Clearly ignore irrelevant architectures (i.e. arm rules on x86)

Don't try to load seccomp (and don't fail) if we are already
seccomp-confined.  Otherwise nested containers fail.

Make it clear that the extra seccomp ctx is only for compat calls
on 64-bit arch.  (This will be extended to arm64 when libseccomp
supports it).  Power may will complicate this (if ever it is supported)
and require a new rethink and rewrite.

NOTE - currently when starting a 32-bit container on 64-bit host,
rules pertaining to 32-bit syscalls (as opposed to once which have
the same syscall #) appear to be ignored.  I can reproduce that without
lxc, so either there is a bug in seccomp or a fundamental
misunderstanding in how I"m merging the contexts.

Rereading the seccomp_rule_add manpage suggests that keeping the seccond
seccomp context may not be necessary, but this is not something I care
to test right now.  If it's true, then the code could be simplified, and
it may solve my concerns about power.

With this patch I'm able to start nested containers (with seccomp
policies defined) including 32-bit and 32-bit-in-64-bit.

[ this patch does not yet add the default seccomp policy ]

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>
seccomp: fix 32-bit rules

When calling seccomp_rule_add(), you must pass the native syscall number
even if the context is a 32-bit context.  So use resolve_name rather
than resolve_name_arch.

Enhance the check of /proc/self/status for Seccomp: so that we do not
enable seccomp policies if seccomp is not built into the kernel.  This
is needed before we can enable by-default seccomp policies (which we
want to do next)

Fix wrong return value check from seccomp_arch_exist, and remove
needless abstraction in arch handling.

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>
ubuntu containers: use a seccomp filter by default (v2)

Blacklist module loading, kexec, and open_by_handle_at (the cause of the
not-docker-specific dockerinit mounts namespace escape).

This should be applied to all arches, but iiuc stgraber will be doing
some reworking of the commonizations which will simplify that, so I'm
not doing it here.

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>
Include ubuntu.priv.seccomp in dist tarball

Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>
Prevent write_config from corrupting container config

write_config doesn't check the value sig_name function returns,
this causes write_config to produce corrupted container config when
using non-predefined signal names.

Signed-off-by: Alexander Vladimirov <alexander.idkfa.vladimirov@gmail.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
attach: Fix querying for the current personality

Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>
Acked-by: Serge Hallyn <serge.hallyn@ubuntu.com>
cgmanager: have cgm_set and cgm_get use absolute path when possible

This allows users to get/set cgroup settings when logged into a different
session than that from which they started the container.

There is no cgmanager command to do an _abs variant of cgmanager_get_value
and cgmanager_set_value.  So we fork off a new task, which enters the
parent cgroup of the started container, then can get/set the value from
there.  The reason not to go straight into the container's cgroup is that
if we are freezing the container, or the container is already frozen, we'll
freeze as well :)  The reason to fork off a new task is that if we are
in a cgroup which is set to remove-on-empty, we may not be able to return
to our original cgroup after making the change.

This should fix https://github.com/lxc/lxc/issues/246

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>
cgm_get: make sure @value is null-terminated

Previously this was done by strncpy, but now we just read
the len bytes - not including \0 - from a pipe, so pre-fill
@value with 0s to be safe.

This fixes the python3 api_test failure.

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Don't call sig_name twice, use pointer instead

Signed-off-by: Alexander Vladimirov <alexander.idkfa.vladimirov@gmail.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
Fix to work lxc-start with unprivileged containers on recent kernel

Change chown_mapped_root() to map in both the root uid and gid, not
just the uid, so as to work lxc-start with unprivileged containers on
recent kernel.

Signed-off-by: TAMUKI Shoichi <tamuki@linet.gr.jp>
Signed-off-by: KATOH Yasufumi <karma@jazz.email.ne.jp>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
Fix to work lxc-destroy with unprivileged containers on recent kernel

Change idmap_add_id() to add both ID_TYPE_UID and ID_TYPE_GID entries
to an existing lxc_conf, not just an ID_TYPE_UID entry, so as to work
lxc-destroy with unprivileged containers on recent kernel.

Signed-off-by: TAMUKI Shoichi <tamuki@linet.gr.jp>
Acked-by: KATOH Yasufumi <karma@jazz.email.ne.jp>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
Cast to gid_t to fix android build failure

stat.st_gid is unsigned long in bionic instead of the expected gid_t, so
just cast it to gid_t.

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

Signed-off-by: Jesse Tane <jesse.tane@gmail.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>
Enable default seccomp profile for all distros

This updates the common config to include Serge's seccomp profile by
default for privileged containers.

Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
chown_mapped_root: don't try chgrp if we don't own the file

New kernels require that to have privilege over a file, your
userns must have the old and new groups mapped into your userns.
So if a file is owned by our uid but another groupid, then we
have to chgrp the file to our primary group before we can try
(in a new user namespace) to chgrp the file to a group id in the
namespace.

But in some cases (when cloning) the file may already be mapped
into the container.  Now we cannot chgrp the file to our own
primary group - and we don't have to.

So detect that case.  Only try to chgrp the file to our primary
group if the file is owned by our euid (i.e. not by the container)
and the owning group is not already mapped into the container by
default.

With this patch, I'm again able to both create and clone containers
with no errors again.

Reported-by: S.Çağlar Onur <caglar@10ur.org>
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>