Deprecate docker_compatible and gpu_passthrough (#121)

Remove --property=DeviceAllow= so it won't interfere with DevicePolicy=auto
Added seccomp config option
Deprecated docker_compatible config option
Deprecated gpu_passthrough config option
Removed the docker_compatible question during interactive create
Updated readme and config templates
Closes https://github.com/Jip-Hop/jailmaker/issues/119
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Jip-Hop 2024-04-22 20:50:40 +02:00 committed by GitHub
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6 changed files with 95 additions and 71 deletions

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@ -160,7 +160,7 @@ See [Advanced Networking](./NETWORKING.md) for more.
## Docker
The `jailmaker` script won't install Docker for you, but it can setup the jail with the capabilities required to run docker. You can manually install Docker inside the jail using the [official installation guide](https://docs.docker.com/engine/install/#server) or use [convenience script](https://get.docker.com). Additionally you may use the [docker config template](./templates/docker/README.md).
Using the [docker config template](./templates/docker/README.md) is recommended if you want to run docker inside the jail. You may of course manually install docker inside a jail. But keep in mind that you need to add `--system-call-filter='add_key keyctl bpf'` (or disable seccomp filtering). It is [not recommended to use host networking for a jail in which you run docker](https://github.com/Jip-Hop/jailmaker/issues/119). Docker needs to manage iptables rules, which it can safely do in its own networking namespace (when using [bridge or macvlan networking](./NETWORKING.md) for the jail).
## Documentation

150
jlmkr.py
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@ -4,7 +4,7 @@
with full access to all files via bind mounts, \
thanks to systemd-nspawn!"""
__version__ = "1.1.4"
__version__ = "1.1.5"
__disclaimer__ = """USE THIS SCRIPT AT YOUR OWN RISK!
IT COMES WITHOUT WARRANTY AND IS NOT SUPPORTED BY IXSYSTEMS."""
@ -38,7 +38,10 @@ from textwrap import dedent
DEFAULT_CONFIG = """startup=0
gpu_passthrough_intel=0
gpu_passthrough_nvidia=0
# The docker_compatible option is deprecated and will be removed in a future release
docker_compatible=0
# Turning off seccomp filtering improves performance at the expense of security
seccomp=1
# Add additional systemd-nspawn flags
# E.g. to mount host storage in the jail (--bind-ro for readonly):
@ -47,7 +50,7 @@ docker_compatible=0
# --network-macvlan=eno1 --resolv-conf=bind-host
# E.g. bridge networking:
# --network-bridge=br1 --resolv-conf=bind-host
# E.g. add capabilities required by docker:
# E.g. allow syscalls required by docker:
# --system-call-filter='add_key keyctl bpf'
systemd_nspawn_user_args=
@ -135,8 +138,7 @@ else:
DISCLAIMER = f"""{YELLOW}{BOLD}{__disclaimer__}{NORMAL}"""
# Used in parser getters to indicate the default behavior when a specific
# option is not found it to raise an exception. Created to enable `None` as
# a valid fallback value.
# option is not found. Created to enable `None` as a valid fallback value.
_UNSET = object()
@ -249,8 +251,8 @@ class KeyValueParser(configparser.ConfigParser):
super().set(self._section_name, option, value)
# Return value for specified option key
def my_get(self, option):
return super().get(self._section_name, option)
def my_get(self, option, fallback=_UNSET):
return super().get(self._section_name, option, fallback=fallback)
# Return value converted to boolean for specified option key
def my_getboolean(self, option, fallback=_UNSET):
@ -302,6 +304,12 @@ def get_jail_rootfs_path(jail_name):
return os.path.join(get_jail_path(jail_name), JAIL_ROOTFS_NAME)
# Test intel GPU by decoding mp4 file (output is discarded)
# Run the commands below in the jail:
# curl -o bunny.mp4 https://www.w3schools.com/html/mov_bbb.mp4
# ffmpeg -hwaccel vaapi -hwaccel_device /dev/dri/renderD128 -hwaccel_output_format vaapi -i bunny.mp4 -f null - && echo 'SUCCESS!'
def passthrough_intel(gpu_passthrough_intel, systemd_nspawn_additional_args):
if not gpu_passthrough_intel:
return
@ -536,6 +544,8 @@ def start_jail(jail_name):
eprint("Aborting...")
return 1
seccomp = config.my_getboolean("seccomp")
# Handle initial setup
initial_setup = config.my_get("initial_setup")
@ -596,19 +606,13 @@ def start_jail(jail_name):
f"--directory={JAIL_ROOTFS_NAME}",
]
# TODO: split the docker_compatible option into separate options
# - privileged (to disable seccomp, set DevicePolicy=auto and add all capabilities)
# "The bottom line is that using the --privileged flag does not tell the container
# engines to add additional security constraints. The --privileged flag does not add
# any privilege over what the processes launching the containers have."
# "Container engines user namespace is not affected by the --privileged flag"
# Meaning in the context of systemd-nspawn I could have a privileged option,
# which would also apply to jails with --private-users (user namespacing)
# https://www.redhat.com/sysadmin/privileged-flag-container-engines
# - how to call the option to enable ip_forward and bridge-nf-call?
# - add CSV value for preloading kernel modules like linux.kernel_modules in LXC
if config.my_getboolean("docker_compatible"):
eprint("WARNING: DEPRECATED OPTION")
eprint(
"The `docker_compatible` option is deprecated and will be removed in a future release."
)
eprint("Please refer to the recommended way to run docker in a jail:")
eprint("https://github.com/Jip-Hop/jailmaker/tree/main/templates/docker")
# Enable ip forwarding on the host (docker needs it)
print(1, file=open("/proc/sys/net/ipv4/ip_forward", "w"))
@ -635,32 +639,8 @@ def start_jail(jail_name):
)
)
# To properly run docker inside the jail, we need to lift restrictions
# Without DevicePolicy=auto images with device nodes may not be pulled
# For example docker pull ljishen/sysbench would fail
# Fortunately I didn't encounter many images with device nodes...
#
# Issue: https://github.com/moby/moby/issues/35245
#
# The systemd-nspawn manual explicitly mentions:
# Device nodes may not be created
# https://www.freedesktop.org/software/systemd/man/systemd-nspawn.html
#
# Workaround: https://github.com/kinvolk/kube-spawn/pull/328
#
# As of 26-3-2024 on TrueNAS-SCALE-23.10.1.1 it seems to no longer be
# required to use DevicePolicy=auto
# Docker can successfully pull the ljishen/sysbench test image
# Running mknod /dev/port c 1 4 manually works too...
# Unknown why this suddenly started working...
# https://github.com/systemd/systemd/issues/21987
#
# Use SYSTEMD_SECCOMP=0: https://github.com/systemd/systemd/issues/18370
systemd_run_additional_args += [
"--setenv=SYSTEMD_SECCOMP=0",
"--property=DevicePolicy=auto",
]
print("The `docker_compatible` option disables seccomp filtering...")
seccomp = False
# Add additional flags required for docker
systemd_nspawn_additional_args += [
@ -683,22 +663,66 @@ def start_jail(jail_name):
)
# Legacy gpu_passthrough config setting
# TODO: deprecate this and stop supporting it
if config.my_getboolean("gpu_passthrough", False):
eprint("WARNING: DEPRECATED OPTION")
eprint(
"The `gpu_passthrough` option is deprecated and will be removed in a future release."
)
eprint(
"Please use `gpu_passthrough_intel` and/or `gpu_passthrough_nvidia` instead."
)
gpu_passthrough_intel = True
gpu_passthrough_nvidia = True
else:
gpu_passthrough_intel = config.my_getboolean("gpu_passthrough_intel")
gpu_passthrough_nvidia = config.my_getboolean("gpu_passthrough_nvidia")
if gpu_passthrough_intel or gpu_passthrough_nvidia:
systemd_nspawn_additional_args.append("--property=DeviceAllow=char-drm rw")
passthrough_intel(gpu_passthrough_intel, systemd_nspawn_additional_args)
passthrough_nvidia(
gpu_passthrough_nvidia, systemd_nspawn_additional_args, jail_name
)
if seccomp is False:
# Disabling seccomp filtering by passing --setenv=SYSTEMD_SECCOMP=0 to systemd-run will improve performance
# at the expense of security: it allows syscalls which otherwise would be blocked or would have to be explicitly allowed by passing
# --system-call-filter to systemd-nspawn
# https://github.com/systemd/systemd/issues/18370
#
# However, and additional layer of seccomp filtering may be undesirable
# For example when using docker to run containers inside the jail created with systemd-nspawn
# Even though seccomp filtering is disabled for the systemd-nspawn jail itself, docker can still use seccomp filtering
# to restrict the actions available within its containers
#
# Proof that seccomp can be used inside a jail started with --setenv=SYSTEMD_SECCOMP=0:
# Run a command in a docker container which is blocked by the default docker seccomp profile:
# docker run --rm -it debian:jessie unshare --map-root-user --user sh -c whoami
# unshare: unshare failed: Operation not permitted
# Now run unconfined to show command runs successfully:
# docker run --rm -it --security-opt seccomp=unconfined debian:jessie unshare --map-root-user --user sh -c whoami
# root
systemd_run_additional_args += [
"--setenv=SYSTEMD_SECCOMP=0",
]
# The systemd-nspawn manual explicitly mentions:
# Device nodes may not be created
# https://www.freedesktop.org/software/systemd/man/systemd-nspawn.html
# This means docker images containing device nodes can't be pulled
# https://github.com/moby/moby/issues/35245
#
# The solution is to use DevicePolicy=auto
# https://github.com/kinvolk/kube-spawn/pull/328
#
# DevicePolicy=auto is the default for systemd-run and allows access to all devices
# as long as we don't add any --property=DeviceAllow= flags
# https://manpages.debian.org/bookworm/systemd/systemd.resource-control.5.en.html
#
# We can now successfully run:
# mknod /dev/port c 1 4
# Or pull docker images containing device nodes:
# docker pull oraclelinux@sha256:d49469769e4701925d5145c2676d5a10c38c213802cf13270ec3a12c9c84d643
cmd = [
"systemd-run",
*shlex.split(config.my_get("systemd_run_default_args")),
@ -1074,19 +1098,6 @@ def interactive_config():
jail_name = ask_jail_name(jail_name)
print(
dedent(
f"""
Docker won't be installed by {COMMAND_NAME}.
But it can setup the jail with the capabilities required to run docker.
You can turn DOCKER_COMPATIBLE mode on/off post-install.
"""
)
)
agree_with_default(
config, "docker_compatible", "Make jail docker compatible right now?"
)
print()
agree_with_default(
config, "gpu_passthrough_intel", "Passthrough the intel GPU (if present)?"
@ -1261,11 +1272,16 @@ def create_jail(**kwargs):
"gpu_passthrough_intel",
"gpu_passthrough_nvidia",
"release",
"seccomp",
"startup",
"systemd_nspawn_user_args",
]:
value = kwargs.pop(option)
if value:
if (
value is not None
and len(value)
and value is not config.my_get(option, None)
):
# TODO: this will wipe all systemd_nspawn_user_args from the template...
# Should there be an option to append them instead?
print(f"Overriding {option} config value with {value}.")
@ -1641,10 +1657,9 @@ def list_jails():
config = parse_config_file(get_jail_config_path(jail_name))
if config:
# TODO: also list privileged once this setting is implemented
jail["startup"] = config.my_getboolean("startup")
# TODO: deprecate gpu_passthrough and stop supporting it
# TODO: remove gpu_passthrough in future release
if config.my_getboolean("gpu_passthrough", False):
jail["gpu_intel"] = True
jail["gpu_nvidia"] = True
@ -2005,6 +2020,13 @@ def main():
"--docker_compatible", #
type=int,
choices=[0, 1],
help="DEPRECATED",
)
commands["create"].add_argument(
"--seccomp", #
type=int,
choices=[0, 1],
help="turning off seccomp filtering improves performance at the expense of security",
)
commands["create"].add_argument(
"-c", #

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@ -1,6 +1,8 @@
startup=0
gpu_passthrough_intel=1
gpu_passthrough_nvidia=0
# Turning off seccomp filtering improves performance at the expense of security
seccomp=1
# Use macvlan networking to provide an isolated network namespace,
# so docker can manage firewall rules

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@ -2,6 +2,8 @@
startup=0
gpu_passthrough_intel=1
gpu_passthrough_nvidia=0
# Turning off seccomp filtering improves performance at the expense of security
seccomp=1
# Use macvlan networking to provide an isolated network namespace,
# so incus can manage firewall rules
@ -9,7 +11,6 @@ gpu_passthrough_nvidia=0
# Ensure to change eno1/br1 to the interface name you want to use
# You may want to add additional options here, e.g. bind mounts
# TODO: don't use --capability=all but specify only the required capabilities
# TODO: or add and use privileged flag?
systemd_nspawn_user_args=--network-macvlan=eno1
--resolv-conf=bind-host
--capability=all
@ -63,8 +64,6 @@ systemd_run_default_args=--property=KillMode=mixed
--property=TasksMax=infinity
--collect
--setenv=SYSTEMD_NSPAWN_LOCK=0
# TODO: add below if required:
# --property=DevicePolicy=auto
systemd_nspawn_default_args=--keep-unit
--quiet

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@ -2,6 +2,8 @@
startup=0
gpu_passthrough_intel=1
gpu_passthrough_nvidia=0
# Turning off seccomp filtering improves performance at the expense of security
seccomp=1
# Use macvlan networking to provide an isolated network namespace,
# so lxd can manage firewall rules
@ -9,7 +11,6 @@ gpu_passthrough_nvidia=0
# Ensure to change eno1/br1 to the interface name you want to use
# You may want to add additional options here, e.g. bind mounts
# TODO: don't use --capability=all but specify only the required capabilities
# TODO: or add and use privileged flag?
systemd_nspawn_user_args=--network-bridge=br1
--resolv-conf=bind-host
--capability=all
@ -49,8 +50,6 @@ systemd_run_default_args=--property=KillMode=mixed
--property=TasksMax=infinity
--collect
--setenv=SYSTEMD_NSPAWN_LOCK=0
# TODO: add below if required:
# --property=DevicePolicy=auto
systemd_nspawn_default_args=--keep-unit
--quiet

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@ -1,6 +1,8 @@
startup=0
gpu_passthrough_intel=0
gpu_passthrough_nvidia=0
# Turning off seccomp filtering improves performance at the expense of security
seccomp=1
# Use macvlan networking to provide an isolated network namespace,
# so podman can manage firewall rules