IDP 5 - Step 1 - Tomcat TLS Non-Root

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Table of contents for step 1

Install pre-requisites

Install required (and used, throughout this documentation) packages, possibly replacing vim with your $EDITOR of choice (e.g. emacs-nox or micro, both of which also support syntax highlighting, which helps when editing XML files) and stop the automatically started tomcat until we've completed more configuration performed further below:

apt install --no-install-recommends default-jdk-headless tomcat10 \
  vim less openssl curl expat multitail gnupg net-tools

systemctl stop tomcat10

Post-install fix-ups

Redirect requests to Tomcat's web root ("/") to a URL of your choice, e.g. your institution's home page, replacing "www.example.edu" in the command  below. The Shibboleth IDP application by default will run at /idp, allowing you to easily add and update other content outside of /idp, e.g. logos or CSS stylesheets without having them to integrate them with the "idp" context/application. The document root for that is in /var/lib/tomcat10/webapps/ROOT/ and nothing in the Shibboleth IDP software (or during use of SAML) by default links to / of the server, so you can use that for locally hosted content without interfering with the IDP application. For example, you will want to add a robots.txt file to avoid unnecessary scanning by well-behaved search bots.

rm /var/lib/tomcat10/webapps/ROOT/index.html
echo '<% response.sendRedirect("https://www.example.edu/"); %>' > /var/lib/tomcat10/webapps/ROOT/index.jsp
echo -e "User-agent: *\nDisallow: /" > /var/lib/tomcat10/webapps/ROOT/robots.txt

Set JAVA_HOME for the current (and future) shell(s):

eval $(echo "export JAVA_HOME=/usr" | tee /etc/profile.d/java.sh)

Enable TLS/SSL

Create keypair and certificate chain

First, create and note down a random passphrase to use for protecting/encrypting the private key at rest. (Use this passphrase in all the steps below when asked for a key passphrase or import/export password.)

openssl rand -hex 16

On the IDP server create an RSA private key of at least 2048 bits size and the CSR for the web server's TLS certificate, supplying the necessary data (at least the subject) on the command line or by entering any data interactively when being prompted for it (when not adding -subj to the command):

openssl req -new -newkey rsa:2048 -out webserver.csr -keyout webserver.key -subj "/CN=WEBSERVER-FQDN"

When asked to "Enter pass phrase for webserver.key" provide the passphrase from the previous step.

openssl pkcs12 -in /etc/tomcat10/webserver.p12 -nocerts | tail +5 > webserver.key

openssl req -new -key webserver.key -out webserver.csr -subj "/CN=WEBSERVER-FQDN"

Equipped with the CSR you can now request a TLS certificate based from your CA, e.g. using the ACOnet TCS supplier. Once the certificate has been issued copy it to the IDP server as webserver.crt.
You'll also need to copy any intermediary Certificate Authority (CA) certificates to the IDP server.

Convert the TLS/SSL keypair into PKCS12

Copy the private key, new TLS certificate and any intermediate CA certificates into a PKCS#12 keystore file:

openssl pkcs12 -export -in webserver.crt -inkey webserver.key -certfile GEANT-OV-RSA-CA-4.crt -name webserver -out webserver.p12

When asked to "Enter pass phrase for webserver.key" provide the passphrase generated earlier.
Again when asked to "Enter Export Password".
And yet again, when asked to "Verifying - Enter Export Password".

Move the newly created keystore to its final location (we're chosing Tomcat's config directory) and set strict file system permissions on it:

[[ -f /etc/tomcat10/webserver.p12 ]] && cp -a /etc/tomcat10/webserver.p12 /etc/tomcat10/webserver.p12.`date -u +%Y%m%d`
mv webserver.p12 /etc/tomcat10/
chown root:tomcat /etc/tomcat10/webserver.p12
chmod 640 /etc/tomcat10/webserver.p12

Configure Tomcat Connector

Remove or comment out all other Connectors in /etc/tomcat10/server.xml, then add the two Connectors as per below, replacing certificateKeystorePassword with the password generated earlier:

<!-- Localhost-only connector for IDP command line tools -->
<Connector address="127.0.0.1" port="80" />

<!-- https://tomcat.apache.org/tomcat-10.1-doc/ssl-howto.html -->
<!-- https://tomcat.apache.org/tomcat-10.1-doc/config/http.html#SSL_Support -->
<Connector
  port="443"
  protocol="org.apache.coyote.http11.Http11NioProtocol"
  maxThreads="150"
  maxPostSize="100000"
  SSLEnabled="true"
  scheme="https"
  secure="true">
  <UpgradeProtocol className="org.apache.coyote.http2.Http2Protocol" />
  <SSLHostConfig>
    <Certificate type="RSA"
      protocols="TLSv1.2,TLSv1.3"
      ciphers="ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384:DHE-RSA-CHACHA20-POLY1305"
      certificateKeystoreType="PKCS12"
      certificateKeystoreFile="/etc/tomcat10/webserver.p12"
      certificateKeystorePassword="see sections above" />
    </SSLHostConfig>
</Connector>

Start Tomcat, check for listening ports, and access https://webserver-fqdn/foo which should result in an HTTP Status 404 error (since /foo won't exist) but allows you to confirm a hopefully valid TLS/SSL webserver configuration:

systemctl restart tomcat10
netstat -lntp | fgrep java  # should show 443, and 80 only on the loopback interface

Verify TLS/SSL

Next validate the TLS/SSL configuration on the system itself with openssl (and quit again with ctrl-c or by typing QUIT into the prompt):

openssl s_client -CApath /etc/ssl/certs/ -connect webserver-fqdn:443 </dev/null

Look for "Certificate chain" in the output from that command, e.g.

openssl s_client -CApath /etc/ssl/certs/ -connect webserver-fqdn:443 2>&1 </dev/null | grep -A8 "^Certificate chain"

and verify that it looks something like the "Certificate chain" presented below. The Subject of cert 0 will obviously differ, and depending on your choice of CA or certificate product the CA or certificate chain may also be different. A correct chain (and therfore PKCS#12 keystore) for TLS usage should contain all the certificates up until but excluding the root CA certificate. I.e, in the example below the certificate with CN=USERTrust RSA Certification Authority is not included in the chain sent from the server (but must be known by the web browser):

Certificate chain
 0 s:C = AT, postalCode = 1010, ST = Wien, L = Wien, street = Universitaetsstrasse 7, O = ACOnet, CN = idp.aco.net
   i:C = NL, O = GEANT Vereniging, CN = GEANT OV RSA CA 4
 1 s:C = NL, O = GEANT Vereniging, CN = GEANT OV RSA CA 4
   i:C = US, ST = New Jersey, L = Jersey City, O = The USERTRUST Network, CN = USERTrust RSA Certification Authority

In case of errors check the output of "journalctl -u tomcat10 -ef".

If everything works fine and the certificate chain looks as expected you can remove the private key and certificate again (as both can be extracted from the PKCS#12 keystore if needed), keeping the CSR in file webserver.csr around for next time you need to renew that certificate (as long as you still consider the matching private key secure):

rm webserver.{key,crt}

Tune log file creation

IDP logs

You might prefer to have the IDP application write its logs to a more standard location in the file system, specifically one outside the application's own directory and on a file system where data usage is expected to grow dynamically (e.g. on /var). To do that simply set the idp.logfiles property in any of the property files read by the IDP, e.g. within conf/idp.properties:

idp.logfiles=/var/log/shibboleth

We also have to create that directory. And in order for the example commands in this documentation to work with either log directory location we'll remove the (still empty) log dir created by the IDP installer and replace it with a symlink to one we just created ourselfs:

install -o tomcat -g root -m 0750 -d /var/log/shibboleth/
cd /opt/shibboleth-idp/ && rmdir logs && ln -s /var/log/shibboleth logs

Tomcat logs

By default Tomcat logs everything multiple times, including to /var/log/tomcat10/catalina.out and /var/log/tomcat10/localhost.*, which we don't care for. So create a backup copy of Tomcat's logging.properties and replace its content with the minumum needed to get Tomcat's stdout/stderr to the console (which ends up in the systemd journal in our configuration). To prevent catalina.out from being created we deacticate it further below (in our "Systemd service" override) by setting the CATALINA_OUT=/dev/null environment variable for the java process.

systemctl stop tomcat10
cp -a /etc/tomcat10/logging.properties /etc/tomcat10/logging.properties.`date -u +%Y%m%d`
 
echo -n 'handlers = java.util.logging.ConsoleHandler
java.util.logging.ConsoleHandler.level = INFO
java.util.logging.ConsoleHandler.formatter = org.apache.juli.SystemdFormatter
org.apache.catalina.core.ContainerBase.[Catalina].[localhost].level = INFO
org.apache.catalina.core.ContainerBase.[Catalina].[localhost].handlers = java.util.logging.ConsoleHandler
' > /etc/tomcat10/logging.properties

Then comment out or delete the whole Valve element at the end of your /etc/tomcat10/server.xml, and replace it with the following one:

<Valve className="org.apache.catalina.valves.AccessLogValve" maxLogMessageBufferSize="320"
       prefix="access" suffix=".log" renameOnRotate="true" pattern="combined" />

After deleting all Tomcat logs (only) access.log should be generated in Tomcat's log directory going forward:

rm -f /var/log/tomcat10/*
systemctl restart tomcat10
ls -l /var/log/tomcat10/
multitail /var/log/tomcat10/* -l 'journalctl -u tomcat10.service -f'  # exit with 'q'
systemctl stop tomcat10

If you're certain there's no catalina.log file being generated anymore also disable the default logrotate config snippet for it:

sed -i 's/^/#/' /etc/logrotate.d/tomcat10

Systemd service

Debian's Tomcat comes with an almost-usable systemd service that needs to be amended in order to:

1. Avoid the systemd-house-of-horror that's still all too common with Tomcat/Java packaging
2. Avoid slow startup times due to use of a blocking /dev/random (cf. Myths about urandom, also linked to from the Shib wiki).
3. Allow the IDP application to write logs and metadata to the filesystem as needed (by adding more ReadWritePaths)
4. Try avoiding the creation of catalina.out (we already have its content in journald using this configuration)

And since we're creating an override for the OS-supplied systemd service unit anyway we'll also set the maximum memory usage there ("-Xmx3g" in the example below, i.e., 3GB).
Adjust this as needed, but 3-4GB should be sufficient even for large metadata aggregates (as are common with Interfederation). Also leave a bit of RAM for the OS. (Not that you should be running anything else on an IDP server.)

install -o root -g root -m 0755 -d /etc/systemd/system/tomcat10.service.d

cat <<'EOF' > /etc/systemd/system/tomcat10.service.d/override.conf
[Service]
Environment="CATALINA_OUT=/dev/null"
Environment="JAVA_OPTS=-Djava.security.egd=file:/dev/urandom -Djava.awt.headless=true -Xmx3g"
Environment="JSSE_OPTS=-Djdk.tls.ephemeralDHKeySize=2048"
ExecStart=
ExecStart=/usr/bin/java \
  $JAVA_OPTS $JSSE_OPTS \
  -classpath ${CATALINA_HOME}/bin/bootstrap.jar:${CATALINA_HOME}/bin/tomcat-juli.jar \
  -Dcatalina.base=${CATALINA_BASE} \
  -Dcatalina.home=${CATALINA_HOME} \
  -Djava.util.logging.config.file=${CATALINA_BASE}/conf/logging.properties \
  -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager \
  -Djava.io.tmpdir=${CATALINA_TMPDIR} \
  org.apache.catalina.startup.Bootstrap
ReadWritePaths=/var/log/shibboleth/
ReadWritePaths=/opt/shibboleth-idp/logs/
ReadWritePaths=/opt/shibboleth-idp/metadata/
EOF

(If you've set "idp.logfiles=/var/log/shibboleth" via the IDP's property files as described in section "IDP logs" above you can remove the line ReadWritePaths=/opt/shibboleth-idp/logs/. The above example config just makes sure IDP logs can get written using either log location.)

Activate the override with systemctl daemon-reload, maybe also verify with systemd-delta | fgrep tomcat