After the runc security advisory[1] the default cgroup device
whitelist was changed.
In previous versions every container had "rwm" (read, write, mknod)
for every device ("a" for all). Typically this was overridden by
container engines like Docker. In LinuxKit we left the permissive
default.
In recent `runc` versions the default allow-all rule was removed,
so a container can only access a device if it is specifically
granted access, which LinuxKit handles via a device: entry.
However it is inconvenient for pkg/format, pkg/mount, pkg/swap
to list all possible block devices up-front. Therefore we add the
ability to grant access to an entire class of device with a single
rule:
```
- path: all
type: b
```
Obviously a paranoid user can still override this with a specific
major/minor number in a device: rule.
[1] https://github.com/opencontainers/runc/security/advisories/GHSA-g54h-m393-cpwq
Signed-off-by: David Scott <dave@recoil.org>
Needed for containerd v1.2.0 otherwise:
$ ctr run -t docker.io/library/hello-world@sha256:f3b3b28a45160805bb16542c9531888519430e9e6d6ffc09d72261b0d26ff74f test
[ 1311.667587] overlayfs: failed to resolve '/var/lib/containerd/io.containerd.snapshotter.v1.overlayfs/snapshots/5/fs': -2
ctr: failed to mount /tmp/containerd-mount111658703: no such file or directory
Signed-off-by: Ian Campbell <ijc@docker.com>
This was done with the following "script":
git rm pkg/{auditd,binfmt,init}/Makefile
sed -e 's/IMAGE=/image: /g' -i pkg/*/Makefile
sed -e 's/NETWORK=1/network: true/g' -i pkg/*/Makefile
sed -e 's/ARCHES=x86_64/arches:\n - amd64/g' -i pkg/*/Makefile
sed -e '/DEPS:\?=/d' -i pkg/*/Makefile
sed -e '/ARCHES=SKIP/d' -i pkg/node_exporter/Makefile
sed -e 's/include \.\.\/package.mk//g' -i pkg/*/Makefile
sed -e '/^$/d' -i pkg/*/Makefile
git mv pkg/node_exporter/Makefile pkg/node_exporter/build.yml-skip
for i in pkg/*/Makefile ; do git mv $i ${i%Makefile}build.yml ; done
and manual update of pkg/Makefile.
Signed-off-by: Ian Campbell <ijc@docker.com>
