Files
scylladb/tools/toolchain/dbuild
Nadav Har'El 5f98b81cb3 dbuild: disable selinux instead of relabeling
By default, Docker uses SELinux to prevent malicious code in the container
from "escaping" and touching files outside the container: The container
is only allowed to touch files with a special SELinux label, which the
outside files simply do not have. However, this means that if you want
to "mount" outside files into the container, Docker needs to add the
special label to them. This is why one needs to use the ":z" option
when mounting an outside file inside docker - it asks docker to "relabel"
the directory to be usable in Docker.

But this relabeling process is slow and potentially harmful if done to
large directories such as your home directory, where you may theoretically
have SELinux labels for other reasons. The relabling is also unnecessary -
we don't really need the SELinux protection in dbuild. Dbuild was meant
to provide a common toolchain - it was never meant to protect the build
host from a malicious build script.

The alternative we use in this patch is "--security-opt label=disable".
This allows the container to access any file in the host filesystem,
but as usual - only if it's explicitly "mounted" into the container.
All ":z" we added in the past can be removed.

Signed-off-by: Nadav Har'El <nyh@scylladb.com>

Closes #10945
2022-07-03 16:20:07 +03:00

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#!/bin/bash
if [[ -f ~/.config/scylladb/dbuild ]]; then
. ~/.config/scylladb/dbuild
fi
function die () {
msg="$1"
if [[ -n "$msg" ]]; then
echo "$(basename $0): $msg." 1>&2
fi
cat <<EOF 1>&2
Run \`$0 --help' to print the full help message.
EOF
exit 1
}
if which docker >/dev/null 2>&1 ; then
tool=${DBUILD_TOOL-docker}
elif which podman >/dev/null 2>&1 ; then
tool=${DBUILD_TOOL-podman}
else
die "Please make sure you install either podman or docker on this machine to run dbuild"
fi
here="$(realpath $(dirname "$0"))"
toplevel="$(realpath "$here/../..")"
group_args=()
docker_args=()
image="$(<"$here/image")"
for gid in $(id -G); do
group_args+=(--group-add "$gid")
done
interactive=
function help () {
cat <<EOF 1>&2
NAME
$(basename $0) - Run a command in scylla's frozen toolchain docker build image.
SYNOPSIS
$0 [OPTIONS --] [command [arg ...]]
DESCRIPTION
$(basename $0) is used mainly to build scylla in a docker image containing
a frozen version of the toolchain.
When no command is provided, $(basename $0) runs an interactive shell in
the docker instance. The image to use is taken by default from "$(dirname $0)/image".
It may be overriden using the --image option.
When providing docker options, the options list must be terminated with \`--'.
OPTIONS
-h | --help
Print this help message.
--image [IMAGE]
Use the specified docker IMAGE.
If omitted, list the available images using \`docker image ls'
-i | --interactive
Run an interactive session.
See \`docker help run' for available options.
ENVIRONMENT
SCYLLADB_DBUILD this variable, which can be a string or a bash
array, is prepended to the parmeters passed to
docker. This can be used to mount the ccache
directory (~/.ccache) and set up environment
variables (e.g. CCACHE_PREFIX)
If the file ~/.config/scylladb/dbuild exists, it is sourced. This can
be used to set up the SCYLLADB_DBUILD environment variable.
EOF
exit 0
}
if [[ $# -eq 0 ]]; then
interactive=y
docker_args=(-it)
elif [[ "$1" = -* ]]; then
while [[ "$1" != "--" && $# != 0 ]]; do
case "$1" in
-h|--help)
help
;;
--image)
image="$2"
shift 2
if [[ -z "$image" ]]; then
die "Expected docker image identifier to follow the --image option"
fi
if ! $tool image inspect "$image" >/dev/null && ! $tool image pull "$image"; then
die
fi
continue
;;
--*)
if [[ "$1" = --interactive || "$1" = --interactive=true ]]; then
interactive=y
fi
;;
-*)
if [[ "$1" = -*i* ]]; then
interactive=y
fi
;;
*)
;;
esac
docker_args+=("$1")
shift
done
if [[ "$1" != "--" ]]; then
die "Expected '--' to terminate docker flag list"
fi
shift
fi
if [[ $# != 0 ]]; then
args=("$@")
else
args=(/bin/bash -i)
fi
MAVEN_LOCAL_REPO="$HOME/.m2"
mkdir -p "$MAVEN_LOCAL_REPO"
is_podman="$($tool --help | grep -o podman)"
docker_common_args=()
docker_common_args+=("${SCYLLADB_DBUILD[@]}")
if [ -z "$is_podman" ]; then
unset TMP_PASSWD
docker_common_args+=(
-u "$(id -u):$(id -g)"
"${group_args[@]}"
-v /etc/passwd:/etc/passwd:ro
-v /etc/group:/etc/group:ro
--pids-limit -1
)
else
TMP_PASSWD=$(mktemp --tmpdir passwd.XXXXXX)
FULLNAME=$(getent passwd $USER | cut -d ':' -f 5)
echo "$USER:x:0:0:$FULLNAME:$HOME:/bin/bash" > "$TMP_PASSWD"
docker_common_args+=(-v "$TMP_PASSWD:/etc/passwd:ro")
# --pids-limit is not supported on podman with cgroupsv1
# detection code from
# https://unix.stackexchange.com/questions/617764/how-do-i-check-if-system-is-using-cgroupv1
if grep -q 'cgroup2.*/sys/fs/cgroup ' /proc/mounts; then
docker_common_args+=(
--pids-limit -1
--annotation run.oci.keep_original_groups=1
)
fi
# if --pids-limit is not supported, add
# [containers]
# pids_limit = 0
#
# to /etc/containers/containers.conf
fi
if [ "$PWD" != "$toplevel" ]; then
docker_common_args+=(-v "$toplevel:$toplevel")
fi
# podman cannot relabel system directories like /tmp, but it can
# relable directories we own, so we map a temporary directory to /tmp
tmpdir=$(mktemp -d)
docker_common_args+=(
--security-opt seccomp=unconfined \
--security-opt label:disable \
--network host \
--cap-add SYS_PTRACE \
-v "$PWD:$PWD" \
-v "$tmpdir:/tmp" \
-v "$MAVEN_LOCAL_REPO:$MAVEN_LOCAL_REPO" \
-v /etc/localtime:/etc/localtime:ro \
-w "$PWD" \
-e HOME="$HOME" \
"${docker_args[@]}" \
"$image" \
"${args[@]}"
)
cleanup() {
rm -rf "$tmpdir"
if [ -v TMP_PASSWD ]; then
rm -f "$TMP_PASSWD"
fi
}
if [[ -n "$interactive" || -n "$is_podman" ]]; then
# If --interactive was given on the command line, we can't run in detached mode
# as it will be impossible to interact with the container.
# We also avoid detached mode with podman, which doesn't need it
# (it does not proxy SIGTERM) and doesn't work well with it.
$tool run --rm "${docker_common_args[@]}"
ret=$?
cleanup
exit $ret
fi
container=$(
$tool run \
"--detach=true" \
"${docker_common_args[@]}"
)
kill_it() {
if [[ -n "$container" ]]; then
$tool rm -f "$container" > /dev/null
container=
fi
cleanup
}
trap kill_it SIGTERM SIGINT SIGHUP EXIT
$tool logs --follow "$container"
if [[ -n "$container" ]]; then
exitcode="$($tool wait "$container")"
else
exitcode=99
fi
kill_it
trap - SIGTERM SIGINT SIGHUP EXIT
# after "docker kill", docker wait will not print anything
[[ -z "$exitcode" ]] && exitcode=1
exit "$exitcode"