Tomcat 8.5 - Is Certificate/SSL required for HTTP2

Question

I found Http2Protocol doc, that it doesn't supports HTTPS?

Some protocols (e.g. HTTP/2) only support HTTP upgrade over non-secure connections.

Is it a typo, or I must use HTTP and not HTTPS when using Tomcat HTTP2 or am I missing something?

<UpgradeProtocol className="org.apache.coyote.http2.Http2Protocol" />

For HTTP connector:

<Connector port="8080" protocol="HTTP/1.1"
           connectionTimeout="20000"/>

And added relevant alpn jar to JAVA_OPT using -Xbootclasspath/p:/path/to/alpn-boot.jar

But it doesn't find matching rule:

org.apache.tomcat.util.digester.Digester.endElement   No rules found matching 'Server/Service/UpgradeProtocol'.

I also tried to add to connector openssl implementation but same results

sslImplementationName="org.apache.tomcat.util.net.openssl.OpenSSLImplementation"

Because Java 8's TLS implementation does not support ALPN (which is required for HTTP/2 over TLS), you must be using an OpenSSL based TLS implementation to enable HTTP/2 support. See the sslImplementationName attribute of the Connector

Must I use Certificate/SSL for HTTP2?

Selaron Selaron · Accepted Answer · 2019-10-28T11:05:30

Encryption is de facto mandatory to use http/2:

Although the standard itself does not require usage of encryption, all major client implementations (Firefox, Chrome, Safari, Opera, IE, Edge) have stated that they will only support HTTP/2 over TLS ...

So you'll need a fully configured SSLHostConfig with Certificate in order to run HTTP/2 over TLS.

A connector like this may work for you:

<Connector SSLEnabled="true" maxThreads="150" port="8443"
    protocol="org.apache.coyote.http11.Http11NioProtocol" scheme="https"
    secure="true"
    sslImplementationName="org.apache.tomcat.util.net.openssl.OpenSSLImplementation">
    <SSLHostConfig certificateVerification="none"
        sslProtocol="TLS">
        <Certificate certificateKeyAlias="myKeyAlias"
            certificateKeystoreFile="/path/to/my/keystore.jks"
            certificateKeystorePassword="myPassword"
            certificateKeystoreType="JKS">
        </Certificate>
    </SSLHostConfig>
    <UpgradeProtocol
        className="org.apache.coyote.http2.Http2Protocol" />
</Connector>

If you want to use NIO2, change protocol to org.apache.coyote.http11.Http11Nio2Protocol.

If you want to use SSL without OpenSSL but use the java implementation JSSE instead, change sslImplementationName="org.apache.tomcat.util.net.jsse.JSSEImplementation" (if provided by your JRE).

Despite the fact that browsers won't upgrade to http/2 on unencrypted connections, it's technically possible to configure a http/2 connector on Apache Tomcat without SSL and use it e.g. with CURL - manually enforcing the http/2 upgrade:

<Connector SSLEnabled="false" maxThreads="150" port="8444" protocol="org.apache.coyote.http11.Http11NioProtocol" secure="false">
    <UpgradeProtocol className="org.apache.coyote.http2.Http2Protocol"/>
</Connector>

CURL debug output:

$ curl http://localhost:8444 -v --http2
...
* Connected to localhost (::1) port 8444 (#0)
> GET / HTTP/1.1
> Host: localhost:8444
> User-Agent: curl/7.60.0
> Accept: */*
> Connection: Upgrade, HTTP2-Settings
> Upgrade: h2c
> HTTP2-Settings: AAMAAABkAARAAAAAAAIAAAAA
>
< HTTP/1.1 101
< Connection: Upgrade
< Upgrade: h2c
< Date: Mon, 28 Oct 2019 12:06:18 GMT
* Received 101
* Using HTTP2, server supports multi-use
* Connection state changed (HTTP/2 confirmed)
* Copying HTTP/2 data in stream buffer to connection buffer after upgrade: len=0
* Connection state changed (MAX_CONCURRENT_STREAMS == 200)!
< HTTP/2 200
< content-type: text/html;charset=UTF-8
< date: Mon, 28 Oct 2019 12:06:18 GMT
<

Tomcat 8.5 - Is Certificate/SSL required for HTTP2

1 Answers