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Merge pull request geoserver#39 from ahennr/tomcat-hardening-cis
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Docker image and Tomcat configuration hardening
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buehner committed Feb 9, 2024
2 parents e1677a9 + 2490a96 commit 3727938
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63 changes: 45 additions & 18 deletions Dockerfile
Original file line number Diff line number Diff line change
Expand Up @@ -30,25 +30,28 @@ ENV CATALINA_OPTS="\$EXTRA_JAVA_OPTS \

# init
RUN apt update \
&& apt -y upgrade \
&& apt install -y --no-install-recommends openssl unzip gdal-bin wget curl openjdk-11-jdk gettext \
&& apt clean \
&& rm -rf /var/cache/apt/* \
&& rm -rf /var/lib/apt/lists/*
&& apt -y upgrade \
&& apt install -y --no-install-recommends openssl unzip gdal-bin wget curl openjdk-11-jdk gettext \
&& apt clean \
&& rm -rf /var/cache/apt/* \
&& rm -rf /var/lib/apt/lists/*

WORKDIR /opt/

RUN wget -q https://archive.apache.org/dist/tomcat/tomcat-9/v${TOMCAT_VERSION}/bin/apache-tomcat-${TOMCAT_VERSION}.tar.gz \
&& tar xf apache-tomcat-${TOMCAT_VERSION}.tar.gz \
&& rm apache-tomcat-${TOMCAT_VERSION}.tar.gz \
&& rm -rf /opt/apache-tomcat-${TOMCAT_VERSION}/webapps/ROOT \
&& rm -rf /opt/apache-tomcat-${TOMCAT_VERSION}/webapps/docs \
&& rm -rf /opt/apache-tomcat-${TOMCAT_VERSION}/webapps/examples
&& tar xf apache-tomcat-${TOMCAT_VERSION}.tar.gz \
&& rm apache-tomcat-${TOMCAT_VERSION}.tar.gz \
&& rm -rf /opt/apache-tomcat-${TOMCAT_VERSION}/webapps/ROOT \
&& rm -rf /opt/apache-tomcat-${TOMCAT_VERSION}/webapps/docs \
&& rm -rf /opt/apache-tomcat-${TOMCAT_VERSION}/webapps/examples \
&& rm -rf /opt/apache-tomcat-${TOMCAT_VERSION}/webapps/host-manager \
&& rm -rf /opt/apache-tomcat-${TOMCAT_VERSION}/webapps/manager

# cleanup
RUN apt purge -y \
&& apt autoremove --purge -y \
&& rm -rf /tmp/*
&& apt autoremove --purge -y \
&& rm -rf /var/lib/apt/lists/* \
&& rm -rf /tmp/*

FROM tomcat as download

Expand All @@ -61,10 +64,10 @@ ENV GEOSERVER_BUILD=$GS_BUILD
WORKDIR /tmp

RUN echo "Downloading GeoServer ${GS_VERSION} ${GS_BUILD}" \
&& wget -q -O /tmp/geoserver.zip $WAR_ZIP_URL \
&& unzip geoserver.zip geoserver.war -d /tmp/ \
&& unzip -q /tmp/geoserver.war -d /tmp/geoserver \
&& rm /tmp/geoserver.war
&& wget -q -O /tmp/geoserver.zip $WAR_ZIP_URL \
&& unzip geoserver.zip geoserver.war -d /tmp/ \
&& unzip -q /tmp/geoserver.war -d /tmp/geoserver \
&& rm /tmp/geoserver.war

FROM tomcat as install

Expand Down Expand Up @@ -118,11 +121,35 @@ COPY $ADDITIONAL_FONTS_PATH /usr/share/fonts/truetype/
RUN rm -rf /tmp/*

# Add default configs
ADD config $CONFIG_DIR
COPY config $CONFIG_DIR

# Apply CIS Apache tomcat recommendations regarding server information
# * Alter the advertised server.info String (2.1 - 2.3)
RUN cd $CATALINA_HOME/lib \
&& jar xf catalina.jar org/apache/catalina/util/ServerInfo.properties \
&& sed -i 's/Apache Tomcat\/'"${TOMCAT_VERSION}"'/i_am_a_teapot/g' org/apache/catalina/util/ServerInfo.properties \
&& sed -i 's/'"${TOMCAT_VERSION}"'/x.y.z/g' org/apache/catalina/util/ServerInfo.properties \
&& sed -i 's/^server.built=.*/server.built=/g' org/apache/catalina/util/ServerInfo.properties \
&& jar uf catalina.jar org/apache/catalina/util/ServerInfo.properties \
&& rm -rf org/apache/catalina/util/ServerInfo.properties

# copy scripts
COPY *.sh /opt/
RUN chmod +x /opt/*.sh

# CIS Docker benchmark: Remove setuid and setgid permissions in the images to prevent privilege escalation attacks within containers.
RUN find / -perm /6000 -type f -exec chmod a-s {} \; || true

# GeoServer user => restrict access to $CATALINA_HOME and GeoServer directories
# See also CIS Docker benchmark and docker best practices
RUN chmod +x /opt/*.sh \
&& groupadd geoserver \
&& useradd --no-log-init -u 2000 -r -g geoserver geoserver \
&& chown -R geoserver:geoserver $CATALINA_HOME \
&& chmod g-w,o-rwx $CATALINA_HOME \
&& chown -R geoserver:geoserver $GEOSERVER_DATA_DIR \
&& chown -R geoserver:geoserver $GEOSERVER_LIB_DIR

USER geoserver

ENTRYPOINT ["/opt/startup.sh"]

Expand Down
20 changes: 17 additions & 3 deletions README.md
Original file line number Diff line number Diff line change
Expand Up @@ -144,8 +144,23 @@ To enable a PostgreSQL JNDI resource, provide the following environment variable

In geoserver, you can then reference this JNDI resource using the name `java:comp/env/jdbc/postgres` (if using default).

For advanced customization of the connection pool, you can provide your own customized "context.xml"
file to Apache Tomcat by mounting it to the container at ``/opt/config_overrides/context.xml``.
## How to use custom (tomcat) configuration files

This image provides default (tomcat) configurations that are located in the `./config/` subdir.

* `context.xml` (see/compare JNDI feature from above)
* `server.xml` (security hardened version by default)

In case you want to fully overwrite such a config file, you can do so by mounting it to the `/opt/config_overrides/` directory of a container.
The `startup.sh` script will then copy (and overwrite) these files to the catalina conf directory before starting tomcat.

Example:

```shell
docker run -it -p 80:8080 \
--mount src="/path/to/my/server.xml",target=/opt/config_overrides/server.xml,type=bind \
docker.osgeo.org/geoserver:2.24.1
```

## How to use the docker-compose demo?

Expand Down Expand Up @@ -192,7 +207,6 @@ The following values cannot really be safely changed (as they are used to downlo
| GEOSERVER_VERSION | Geoserver version (used internally) | `2.24-SNAPSHOT`|
| GEOSERVER_BUILD | Geosever build (used internally) | `1628` |


## Troubleshooting

### How to watch geoserver.log from host?
Expand Down
2 changes: 1 addition & 1 deletion config/context.xml
Original file line number Diff line number Diff line change
Expand Up @@ -17,4 +17,4 @@
validationQuery="SELECT 1"
rollbackOnReturn="true"
/>
</Context>
</Context>
187 changes: 187 additions & 0 deletions config/server.xml
Original file line number Diff line number Diff line change
@@ -0,0 +1,187 @@
<?xml version="1.0" encoding="UTF-8"?>
<!--
Licensed to the Apache Software Foundation (ASF) under one or more
contributor license agreements. See the NOTICE file distributed with
this work for additional information regarding copyright ownership.
The ASF licenses this file to You under the Apache License, Version 2.0
(the "License"); you may not use this file except in compliance with
the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
-->
<!-- Note: A "Server" is not itself a "Container", so you may not
define subcomponents such as "Valves" at this level.
Documentation at /docs/config/server.html
-->
<Server port="8005" shutdown="SHUTDOWN">
<Listener className="org.apache.catalina.startup.VersionLoggerListener" />
<!-- Security listener. Documentation at /docs/config/listeners.html
<Listener className="org.apache.catalina.security.SecurityListener" />
-->
<!-- APR library loader. Documentation at /docs/apr.html -->
<Listener className="org.apache.catalina.core.AprLifecycleListener" SSLEngine="on" />
<!-- Prevent memory leaks due to use of particular java/javax APIs-->
<Listener className="org.apache.catalina.core.JreMemoryLeakPreventionListener" />
<Listener className="org.apache.catalina.mbeans.GlobalResourcesLifecycleListener" />
<Listener className="org.apache.catalina.core.ThreadLocalLeakPreventionListener" />

<!-- Global JNDI resources
Documentation at /docs/jndi-resources-howto.html
-->
<GlobalNamingResources>
<!-- Editable user database that can also be used by
UserDatabaseRealm to authenticate users
-->
<Resource name="UserDatabase" auth="Container"
type="org.apache.catalina.UserDatabase"
description="User database that can be updated and saved"
factory="org.apache.catalina.users.MemoryUserDatabaseFactory"
pathname="conf/tomcat-users.xml" />
</GlobalNamingResources>

<!-- A "Service" is a collection of one or more "Connectors" that share
a single "Container" Note: A "Service" is not itself a "Container",
so you may not define subcomponents such as "Valves" at this level.
Documentation at /docs/config/service.html
-->
<Service name="Catalina">

<!--The connectors can use a shared executor, you can define one or more named thread pools-->
<!--
<Executor name="tomcatThreadPool" namePrefix="catalina-exec-"
maxThreads="150" minSpareThreads="4"/>
-->


<!-- A "Connector" represents an endpoint by which requests are received
and responses are returned. Documentation at :
Java HTTP Connector: /docs/config/http.html
Java AJP Connector: /docs/config/ajp.html
APR (HTTP/AJP) Connector: /docs/apr.html
Define a non-SSL/TLS HTTP/1.1 Connector on port 8080
-->
<!--
# 2.6 Turn off TRACE
-->
<Connector
port="8080"
protocol="HTTP/1.1"
connectionTimeout="20000"
redirectPort="8443"
maxParameterCount="1000"
allowTrace="false"
xpoweredBy="false"
/>
<!-- A "Connector" using the shared thread pool-->
<!--
<Connector executor="tomcatThreadPool"
port="8080" protocol="HTTP/1.1"
connectionTimeout="20000"
redirectPort="8443"
maxParameterCount="1000"
/>
-->
<!-- Define an SSL/TLS HTTP/1.1 Connector on port 8443
This connector uses the NIO implementation. The default
SSLImplementation will depend on the presence of the APR/native
library and the useOpenSSL attribute of the AprLifecycleListener.
Either JSSE or OpenSSL style configuration may be used regardless of
the SSLImplementation selected. JSSE style configuration is used below.
-->
<!--
<Connector port="8443" protocol="org.apache.coyote.http11.Http11NioProtocol"
maxThreads="150" SSLEnabled="true"
maxParameterCount="1000"
>
<SSLHostConfig>
<Certificate certificateKeystoreFile="conf/localhost-rsa.jks"
type="RSA" />
</SSLHostConfig>
</Connector>
-->
<!-- Define an SSL/TLS HTTP/1.1 Connector on port 8443 with HTTP/2
This connector uses the APR/native implementation which always uses
OpenSSL for TLS.
Either JSSE or OpenSSL style configuration may be used. OpenSSL style
configuration is used below.
-->
<!--
<Connector port="8443" protocol="org.apache.coyote.http11.Http11AprProtocol"
maxThreads="150" SSLEnabled="true"
maxParameterCount="1000"
>
<UpgradeProtocol className="org.apache.coyote.http2.Http2Protocol" />
<SSLHostConfig>
<Certificate certificateKeyFile="conf/localhost-rsa-key.pem"
certificateFile="conf/localhost-rsa-cert.pem"
certificateChainFile="conf/localhost-rsa-chain.pem"
type="RSA" />
</SSLHostConfig>
</Connector>
-->

<!-- Define an AJP 1.3 Connector on port 8009 -->
<!--
<Connector protocol="AJP/1.3"
address="::1"
port="8009"
redirectPort="8443"
maxParameterCount="1000"
/>
-->

<!-- An Engine represents the entry point (within Catalina) that processes
every request. The Engine implementation for Tomcat stand alone
analyzes the HTTP headers included with the request, and passes them
on to the appropriate Host (virtual host).
Documentation at /docs/config/engine.html -->

<!-- You should set jvmRoute to support load-balancing via AJP ie :
<Engine name="Catalina" defaultHost="localhost" jvmRoute="jvm1">
-->
<Engine name="Catalina" defaultHost="localhost">

<!--For clustering, please take a look at documentation at:
/docs/cluster-howto.html (simple how to)
/docs/config/cluster.html (reference documentation) -->
<!--
<Cluster className="org.apache.catalina.ha.tcp.SimpleTcpCluster"/>
-->

<!-- Use the LockOutRealm to prevent attempts to guess user passwords
via a brute-force attack -->
<Realm className="org.apache.catalina.realm.LockOutRealm">
<!-- This Realm uses the UserDatabase configured in the global JNDI
resources under the key "UserDatabase". Any edits
that are performed against this UserDatabase are immediately
available for use by the Realm. -->
<Realm className="org.apache.catalina.realm.UserDatabaseRealm"
resourceName="UserDatabase"/>
</Realm>

<Host name="localhost" appBase="webapps"
unpackWARs="true" autoDeploy="true">

<!-- SingleSignOn valve, share authentication between web applications
Documentation at: /docs/config/valve.html -->
<!--
<Valve className="org.apache.catalina.authenticator.SingleSignOn" />
-->

<!-- Access log processes all example.
Documentation at: /docs/config/valve.html
Note: The pattern used is equivalent to using pattern="common" -->
<Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs"
prefix="localhost_access_log" suffix=".txt"
pattern="%h %l %u %t &quot;%r&quot; %s %b" />

</Host>
</Engine>
</Service>
</Server>
39 changes: 29 additions & 10 deletions startup.sh
Original file line number Diff line number Diff line change
@@ -1,6 +1,20 @@
#!/bin/sh
#!/bin/bash
echo "Welcome to GeoServer $GEOSERVER_VERSION"

# function that can be used to copy a custom config file to the catalina conf dir
function copy_custom_config() {
CONFIG_FILE=$1
# Use a custom "${CONFIG_FILE}" if the user mounted one into the container
if [ -d "${CONFIG_OVERRIDES_DIR}" ] && [ -f "${CONFIG_OVERRIDES_DIR}/${CONFIG_FILE}" ]; then
echo "Installing configuration override for ${CONFIG_FILE} with substituted environment variables"
envsubst < "${CONFIG_OVERRIDES_DIR}"/"${CONFIG_FILE}" > "${CATALINA_HOME}/conf/${CONFIG_FILE}"
else
# Otherwise use the default
echo "Installing default ${CONFIG_FILE} with substituted environment variables"
envsubst < "${CONFIG_DIR}"/"${CONFIG_FILE}" > "${CATALINA_HOME}/conf/${CONFIG_FILE}"
fi
}

## Skip demo data
if [ "${SKIP_DEMO_DATA}" = "true" ]; then
unset GEOSERVER_REQUIRE_FILE
Expand Down Expand Up @@ -101,15 +115,20 @@ if [ "${POSTGRES_JNDI_ENABLED}" = "true" ]; then
fi

# Use a custom "context.xml" if the user mounted one into the container
if [ -d "${CONFIG_OVERRIDES_DIR}" ] && [ -f "${CONFIG_OVERRIDES_DIR}/context.xml" ]; then
echo "Installing configuration override for context.xml with substituted environment variables"
envsubst < "${CONFIG_OVERRIDES_DIR}"/context.xml > "${CATALINA_HOME}/conf/context.xml"
else
# Otherwise use the default
echo "Installing default context.xml with substituted environment variables"
envsubst < "${CONFIG_DIR}"/context.xml > "${CATALINA_HOME}/conf/context.xml"
fi
copy_custom_config context.xml
fi

# Use a custom "server.xml" if the user mounted one into the container
copy_custom_config server.xml

# start the tomcat
exec $CATALINA_HOME/bin/catalina.sh run
# CIS - Tomcat Benchmark recommendations:
# * Turn off session facade recycling
# * Set a nondeterministic Shutdown command value
if [ ! "${ENABLE_DEFAULT_SHUTDOWN}" = "true" ]; then
REPLACEMENT="$(echo $RANDOM | md5sum | head -c 10)"
sed -i 's/SHUTDOWN/'"$REPLACEMENT"'/g' "$CATALINA_HOME/conf/server.xml"
REPLACEMENT=
fi

exec $CATALINA_HOME/bin/catalina.sh run -Dorg.apache.catalina.connector.RECYCLE_FACADES=true

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