1 개요
- /usr/local/bin/dockerd-entrypoint.sh
#!/bin/sh
set -eu
_tls_ensure_private() {
local f="$1"; shift
[ -s "$f" ] || openssl genrsa -out "$f" 4096
}
_tls_san() {
{
ip -oneline address | awk '{ gsub(/\/.+$/, "", $4); print "IP:" $4 }'
{
cat /etc/hostname
echo 'docker'
echo 'localhost'
hostname -f
hostname -s
} | sed 's/^/DNS:/'
[ -z "${DOCKER_TLS_SAN:-}" ] || echo "$DOCKER_TLS_SAN"
} | sort -u | xargs printf '%s,' | sed "s/,\$//"
}
_tls_generate_certs() {
local dir="$1"; shift
# if server/{ca,key,cert}.pem && !ca/key.pem, do NOTHING except verify (user likely managing CA themselves)
# if ca/key.pem || !ca/cert.pem, generate CA public if necessary
# if ca/key.pem, generate server public
# if ca/key.pem, generate client public
# (regenerating public certs every startup to account for SAN/IP changes and/or expiration)
if [ -s "$dir/server/ca.pem" ] && [ -s "$dir/server/cert.pem" ] && [ -s "$dir/server/key.pem" ] && [ ! -s "$dir/ca/key.pem" ]; then
openssl verify -CAfile "$dir/server/ca.pem" "$dir/server/cert.pem"
return 0
fi
# https://github.com/FiloSottile/mkcert/issues/174
local certValidDays='825'
if [ -s "$dir/ca/key.pem" ] || [ ! -s "$dir/ca/cert.pem" ]; then
# if we either have a CA private key or do *not* have a CA public key, then we should create/manage the CA
mkdir -p "$dir/ca"
_tls_ensure_private "$dir/ca/key.pem"
openssl req -new -key "$dir/ca/key.pem" \
-out "$dir/ca/cert.pem" \
-subj '/CN=docker:dind CA' -x509 -days "$certValidDays"
fi
if [ -s "$dir/ca/key.pem" ]; then
# if we have a CA private key, we should create/manage a server key
mkdir -p "$dir/server"
_tls_ensure_private "$dir/server/key.pem"
openssl req -new -key "$dir/server/key.pem" \
-out "$dir/server/csr.pem" \
-subj '/CN=docker:dind server'
cat > "$dir/server/openssl.cnf" <<-EOF
[ x509_exts ]
subjectAltName = $(_tls_san)
EOF
openssl x509 -req \
-in "$dir/server/csr.pem" \
-CA "$dir/ca/cert.pem" \
-CAkey "$dir/ca/key.pem" \
-CAcreateserial \
-out "$dir/server/cert.pem" \
-days "$certValidDays" \
-extfile "$dir/server/openssl.cnf" \
-extensions x509_exts
cp "$dir/ca/cert.pem" "$dir/server/ca.pem"
openssl verify -CAfile "$dir/server/ca.pem" "$dir/server/cert.pem"
fi
if [ -s "$dir/ca/key.pem" ]; then
# if we have a CA private key, we should create/manage a client key
mkdir -p "$dir/client"
_tls_ensure_private "$dir/client/key.pem"
chmod 0644 "$dir/client/key.pem" # openssl defaults to 0600 for the private key, but this one needs to be shared with arbitrary client contexts
openssl req -new \
-key "$dir/client/key.pem" \
-out "$dir/client/csr.pem" \
-subj '/CN=docker:dind client'
cat > "$dir/client/openssl.cnf" <<-'EOF'
[ x509_exts ]
extendedKeyUsage = clientAuth
EOF
openssl x509 -req \
-in "$dir/client/csr.pem" \
-CA "$dir/ca/cert.pem" \
-CAkey "$dir/ca/key.pem" \
-CAcreateserial \
-out "$dir/client/cert.pem" \
-days "$certValidDays" \
-extfile "$dir/client/openssl.cnf" \
-extensions x509_exts
cp "$dir/ca/cert.pem" "$dir/client/ca.pem"
openssl verify -CAfile "$dir/client/ca.pem" "$dir/client/cert.pem"
fi
}
# no arguments passed
# or first arg is `-f` or `--some-option`
if [ "$#" -eq 0 ] || [ "${1#-}" != "$1" ]; then
# set "dockerSocket" to the default "--host" *unix socket* value (for both standard or rootless)
uid="$(id -u)"
if [ "$uid" = '0' ]; then
dockerSocket='unix:///var/run/docker.sock'
else
# if we're not root, we must be trying to run rootless
: "${XDG_RUNTIME_DIR:=/run/user/$uid}"
dockerSocket="unix://$XDG_RUNTIME_DIR/docker.sock"
fi
case "${DOCKER_HOST:-}" in
unix://*)
dockerSocket="$DOCKER_HOST"
;;
esac
# add our default arguments
if [ -n "${DOCKER_TLS_CERTDIR:-}" ]; then
_tls_generate_certs "$DOCKER_TLS_CERTDIR"
# generate certs and use TLS if requested/possible (default in 19.03+)
set -- dockerd \
--host="$dockerSocket" \
--host=tcp://0.0.0.0:2376 \
--tlsverify \
--tlscacert "$DOCKER_TLS_CERTDIR/server/ca.pem" \
--tlscert "$DOCKER_TLS_CERTDIR/server/cert.pem" \
--tlskey "$DOCKER_TLS_CERTDIR/server/key.pem" \
"$@"
DOCKERD_ROOTLESS_ROOTLESSKIT_FLAGS="${DOCKERD_ROOTLESS_ROOTLESSKIT_FLAGS:-} -p 0.0.0.0:2376:2376/tcp"
else
# TLS disabled (-e DOCKER_TLS_CERTDIR='') or missing certs
set -- dockerd \
--host="$dockerSocket" \
--host=tcp://0.0.0.0:2375 \
"$@"
DOCKERD_ROOTLESS_ROOTLESSKIT_FLAGS="${DOCKERD_ROOTLESS_ROOTLESSKIT_FLAGS:-} -p 0.0.0.0:2375:2375/tcp"
fi
fi
if [ "$1" = 'dockerd' ]; then
# explicitly remove Docker's default PID file to ensure that it can start properly if it was stopped uncleanly (and thus didn't clean up the PID file)
find /run /var/run -iname 'docker*.pid' -delete || :
# XXX inject "docker-init" (tini) as pid1 to workaround https://github.com/docker-library/docker/issues/318 (zombie container-shim processes)
set -- docker-init -- "$@"
iptablesLegacy=
if [ -n "${DOCKER_IPTABLES_LEGACY+x}" ]; then
# let users choose explicitly to legacy or not to legacy
iptablesLegacy="$DOCKER_IPTABLES_LEGACY"
if [ -n "$iptablesLegacy" ]; then
modprobe ip_tables || :
else
modprobe nf_tables || :
fi
elif (
# https://git.netfilter.org/iptables/tree/iptables/nft-shared.c?id=f5cf76626d95d2c491a80288bccc160c53b44e88#n420
# https://github.com/docker-library/docker/pull/468#discussion_r1442131459
for f in /proc/net/ip_tables_names /proc/net/ip6_tables_names /proc/net/arp_tables_names; do
if b="$(cat "$f")" && [ -n "$b" ]; then
exit 0
fi
done
exit 1
); then
# if we already have any "legacy" iptables rules, we should always use legacy
iptablesLegacy=1
elif ! iptables -nL > /dev/null 2>&1; then
# if iptables fails to run, chances are high the necessary kernel modules aren't loaded (perhaps the host is using xtables, for example)
# https://github.com/docker-library/docker/issues/350
# https://github.com/moby/moby/issues/26824
# https://github.com/docker-library/docker/pull/437#issuecomment-1854900620
modprobe nf_tables || :
if ! iptables -nL > /dev/null 2>&1; then
# might be host has no nf_tables, but Alpine is all-in now (so let's try a legacy fallback)
modprobe ip_tables || :
if /usr/local/sbin/.iptables-legacy/iptables -nL > /dev/null 2>&1; then
iptablesLegacy=1
fi
fi
fi
if [ -n "$iptablesLegacy" ]; then
# see https://github.com/docker-library/docker/issues/463 (and the dind Dockerfile where this directory is set up)
export PATH="/usr/local/sbin/.iptables-legacy:$PATH"
fi
iptables --version # so users can see whether it's legacy or not
uid="$(id -u)"
if [ "$uid" != '0' ]; then
# if we're not root, we must be trying to run rootless
if ! command -v rootlesskit > /dev/null; then
echo >&2 "error: attempting to run rootless dockerd but missing 'rootlesskit' (perhaps the 'docker:dind-rootless' image variant is intended?)"
exit 1
fi
user="$(id -un 2>/dev/null || :)"
if ! grep -qE "^($uid${user:+|$user}):" /etc/subuid || ! grep -qE "^($uid${user:+|$user}):" /etc/subgid; then
echo >&2 "error: attempting to run rootless dockerd but missing necessary entries in /etc/subuid and/or /etc/subgid for $uid"
exit 1
fi
: "${XDG_RUNTIME_DIR:=/run/user/$uid}"
export XDG_RUNTIME_DIR
if ! mkdir -p "$XDG_RUNTIME_DIR" || [ ! -w "$XDG_RUNTIME_DIR" ] || ! mkdir -p "$HOME/.local/share/docker" || [ ! -w "$HOME/.local/share/docker" ]; then
echo >&2 "error: attempting to run rootless dockerd but need writable HOME ($HOME) and XDG_RUNTIME_DIR ($XDG_RUNTIME_DIR) for user $uid"
exit 1
fi
if [ -f /proc/sys/kernel/unprivileged_userns_clone ] && unprivClone="$(cat /proc/sys/kernel/unprivileged_userns_clone)" && [ "$unprivClone" != '1' ]; then
echo >&2 "error: attempting to run rootless dockerd but need 'kernel.unprivileged_userns_clone' (/proc/sys/kernel/unprivileged_userns_clone) set to 1"
exit 1
fi
if [ -f /proc/sys/user/max_user_namespaces ] && maxUserns="$(cat /proc/sys/user/max_user_namespaces)" && [ "$maxUserns" = '0' ]; then
echo >&2 "error: attempting to run rootless dockerd but need 'user.max_user_namespaces' (/proc/sys/user/max_user_namespaces) set to a sufficiently large value"
exit 1
fi
# TODO overlay support detection?
exec rootlesskit \
--net="${DOCKERD_ROOTLESS_ROOTLESSKIT_NET:-vpnkit}" \
--mtu="${DOCKERD_ROOTLESS_ROOTLESSKIT_MTU:-1500}" \
--disable-host-loopback \
--port-driver=builtin \
--copy-up=/etc \
--copy-up=/run \
${DOCKERD_ROOTLESS_ROOTLESSKIT_FLAGS:-} \
"$@"
elif [ -x '/usr/local/bin/dind' ]; then
# if we have the (mostly defunct now) Docker-in-Docker wrapper script, use it
set -- '/usr/local/bin/dind' "$@"
fi
else
# if it isn't `dockerd` we're trying to run, pass it through `docker-entrypoint.sh` so it gets `DOCKER_HOST` set appropriately too
set -- docker-entrypoint.sh "$@"
fi
exec "$@"
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