We now have one place that keeps track of (most) devices that are allowed and created within the container. That place is pkg/libcontainer/devices/devices.go
This fixes several inconsistencies between which devices were created in the lxc backend and the native backend. It also fixes inconsistencies between wich devices were created and which were allowed. For example, /dev/full was being created but it was not allowed within the cgroup. It also declares the file modes and permissions of the default devices, rather than copying them from the host. This is in line with docker's philosphy of not being host dependent.
Docker-DCO-1.1-Signed-off-by: Timothy Hobbs <timothyhobbs@seznam.cz> (github: https://github.com/timthelion)
Fixes#5692
This change requires lxc 1.0+ to work and breaks lxc versions less than
1.0 for host networking. We think that this is a find tradeoff by
bumping docker to only support lxc 1.0
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
All modern distros set up /run to be a tmpfs, see for instance:
https://wiki.debian.org/ReleaseGoals/RunDirectory
Its a very useful place to store pid-files, sockets and other things
that only live at runtime and that should not be stored in the image.
This is also useful when running systemd inside a container, as it
will try to mount /run if not already mounted, which will fail for
non-privileged container.
Docker-DCO-1.1-Signed-off-by: Alexander Larsson <alexl@redhat.com> (github: alexlarsson)
This also cleans up some of the left over restriction paths code from
before.
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
It has been pointed out that some files in /proc and /sys can be used
to break out of containers. However, if those filesystems are mounted
read-only, most of the known exploits are mitigated, since they rely
on writing some file in those filesystems.
This does not replace security modules (like SELinux or AppArmor), it
is just another layer of security. Likewise, it doesn't mean that the
other mitigations (shadowing parts of /proc or /sys with bind mounts)
are useless. Those measures are still useful. As such, the shadowing
of /proc/kcore is still enabled with both LXC and native drivers.
Special care has to be taken with /proc/1/attr, which still needs to
be mounted read-write in order to enable the AppArmor profile. It is
bind-mounted from a private read-write mount of procfs.
All that enforcement is done in dockerinit. The code doing the real
work is in libcontainer. The init function for the LXC driver calls
the function from libcontainer to avoid code duplication.
Docker-DCO-1.1-Signed-off-by: Jérôme Petazzoni <jerome@docker.com> (github: jpetazzo)
