FROM docker.io/alpine:3.17.2 ARG OPENSSH_SERVER_PACKAGE_VERSION=9.1_p1-r2 ENV SSHD_HOST_KEYS_DIR=/etc/ssh/host_keys ENV CLIENT_USER=nonroot ENV CLIENT_HOME=/home/$CLIENT_USER ARG CHROOT_PATH=/data RUN apk add --no-cache \ openssh-server="$OPENSSH_SERVER_PACKAGE_VERSION" \ openssh-sftp-server="$OPENSSH_SERVER_PACKAGE_VERSION" \ && mkdir "$SSHD_HOST_KEYS_DIR" \ && adduser -S -h "$CLIENT_HOME" "$CLIENT_USER" \ && sed -i "s/^$CLIENT_USER:!:/$CLIENT_USER:*:/" /etc/shadow \ && mkdir "$CLIENT_HOME/.ssh" \ && chmod -c a+rX "$CLIENT_HOME/.ssh" \ && mkdir "$CHROOT_PATH" \ && chmod -c a+rX "$CHROOT_PATH" VOLUME $SSHD_HOST_KEYS_DIR VOLUME $CHROOT_PATH COPY sshd_config /etc/ssh/sshd_config EXPOSE 2200/tcp ENV SSH_CLIENT_PUBLIC_KEYS= COPY entrypoint.sh / ENTRYPOINT ["/entrypoint.sh"] # uid=0 required for ChrootDirectory option # https://unix.stackexchange.com/a/224329/155174 USER 0 CMD ["/usr/sbin/sshd", "-D", "-e"] # https://github.com/opencontainers/image-spec/blob/v1.0.1/annotations.md ARG REVISION= LABEL org.opencontainers.image.title="single-user openssh server restricted to sftp access" \ org.opencontainers.image.source="https://github.com/fphammerle/docker-sftpd" \ org.opencontainers.image.revision="$REVISION"