Dockerfile-dind-certs

# syntax=docker/dockerfile:1

ARG PYTHON_VERSION=3.14

FROM python:${PYTHON_VERSION}
RUN mkdir /tmp/certs
VOLUME /certs

WORKDIR /tmp/certs

# ---- CA (with proper v3_ca) ----
RUN openssl genrsa -aes256 -passout pass:foobar -out ca-key.pem 4096
COPY <<'EOF' /tmp/ca.cnf
[req]
prompt = no
distinguished_name = req_distinguished_name
x509_extensions = v3_ca

[req_distinguished_name]
countryName = AU

[v3_ca]
basicConstraints = critical, CA:TRUE
keyUsage = critical, keyCertSign, cRLSign
subjectKeyIdentifier = hash
authorityKeyIdentifier = keyid:always,issuer
EOF
RUN openssl req -new -x509 -passin pass:foobar -config /tmp/ca.cnf -days 365 -key ca-key.pem -sha256 -out ca.pem

# ---- Server cert (SAN + KU/EKU) ----
RUN openssl genrsa -out server-key.pem 4096
RUN openssl req -subj "/CN=docker" -sha256 -new -key server-key.pem -out server.csr
COPY <<'EOF' /tmp/server-ext.cnf
basicConstraints = CA:FALSE
keyUsage = critical, digitalSignature, keyEncipherment
extendedKeyUsage = serverAuth
subjectAltName = DNS:docker, DNS:localhost
EOF
RUN openssl x509 -req -days 365 -passin pass:foobar -sha256 -in server.csr -CA ca.pem -CAkey ca-key.pem -CAcreateserial -out server-cert.pem -extfile /tmp/server-ext.cnf

# ---- Client cert (KU/EKU) ----
RUN openssl genrsa -out key.pem 4096
RUN openssl req -passin pass:foobar -subj '/CN=client' -new -key key.pem -out client.csr
COPY <<'EOF' /tmp/client-ext.cnf
basicConstraints = CA:FALSE
keyUsage = critical, digitalSignature
extendedKeyUsage = clientAuth
EOF
RUN openssl x509 -req -passin pass:foobar -days 365 -sha256 -in client.csr -CA ca.pem -CAkey ca-key.pem -CAcreateserial -out cert.pem -extfile /tmp/client-ext.cnf
RUN chmod -v 0400 ca-key.pem key.pem server-key.pem
RUN chmod -v 0444 ca.pem server-cert.pem cert.pem

CMD cp -R /tmp/certs/* /certs && while true; do sleep 1; done