setting up the besu user:group for the docker container and following best security practices (#1093)

Signed-off-by: Joshua Fernandes <joshua.fernandes@consensys.net>

docker/Dockerfile

@@ -1,9 +1,14 @@
 
-FROM openjdk:11.0.2-jre-slim-stretch
+FROM openjdk:11.0.7-jre-slim-buster
 
-COPY besu /opt/besu/
+RUN adduser --disabled-password --gecos "" --home /opt/besu besu && \
+    chown besu:besu /opt/besu
+
+USER besu
 WORKDIR /opt/besu
 
+COPY --chown=besu:besu besu /opt/besu/
+
 # Expose services ports
 # 8545 HTTP JSON-RPC
 # 8546 WS JSON-RPC

docker/tests/01/goss.yaml

@@ -4,22 +4,22 @@ file:
   /opt/besu/bin/besu:
     exists: true
     mode: "0755"
-    owner: root
-    group: root
+    owner: besu
+    group: besu
     filetype: file
     contains: []
   /opt/besu/database:
     exists: true
     mode: "0755"
-    owner: root
-    group: root
+    owner: besu
+    group: besu
     filetype: directory
     contains: []
   /opt/besu/key:
     exists: true
     mode: "0600"
-    owner: root
-    group: root
+    owner: besu
+    group: besu
     filetype: file
     contains: []
 process: