diff --git a/Dockerfile b/Dockerfile
index 437b516b3c452c04f36ffbef4135214a25485086..d8603967f22951fd8e8866fe5eb3b37e67c8d0af 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -4,6 +4,8 @@ RUN mkdir -p /src /dist /reveal_js
 RUN ln -snf /src /reveal_js/src
 RUN ln -snf /dist /reveal_js/dist
 
+RUN umask 0044
+
 COPY package*.json /reveal_js/
 
 WORKDIR /reveal_js
@@ -19,6 +21,8 @@ RUN tar xvfz /tmp/pandoc.tar.gz -C /usr/local --strip-components=1 \
 
 COPY . /reveal_js
 
+RUN chmod -R +rX /reveal_js /usr/local
+
 EXPOSE 80/tcp 8899/tcp
 
 ENTRYPOINT ["/reveal_js/node_modules/.bin/grunt"]