ReproMutualTLSAuthenticationJitsi

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Background[edit]

As of reSIProcate 1.8, the repro proxy supports Mutual (client) TLS authentication.

This means various things:

  • external users can be trusted based on the client certificate they present
  • local users can be trusted based on the client certificate they present
  • this works with or without a challenge password: you can still demand the local user to pass DIGEST authentication, or you can turn off DIGEST authentication and just rely on the client certificate

Using it in practice - with Jitsi[edit]

Jitsi is an excellent, free and open source softphone. It has support for mutual TLS authentication.

This guide explains how to use that feature with repro

Minimum requirements[edit]

  • Require repro v1.8.2 or greater
  • Require Jitsi build 3912 or later (tested with 4142, the nightly build from 31 July 2012)

Other comments about the environment where this was tested:

  • Jitsi on a Debian 6.0 (squeeze, amd64) system with Oracle JRE 1.6.24
  • repro on a Debian 7.0 (wheezy pre-release, i386)
  • Free 4096 bit RSA certificates from [[1]] used on both client and server
  • Normal CN certificates were tested (without subjectAltName or other extensions - that is for another day)

Setup the repro server[edit]

  • Install the latest Debian 7.0 wheezy build
  • Install the repro package:

# apt-get update
# apt-get install repro openssl

  • Create server certificates (note we are giving examples for pocock.com.au - insert your own domain instead)

# openssl genrsa -out /etc/repro/ssl/domain_key_pocock.com.au.pem 4096
# chmod 0640 /etc/repro/ssl/domain_key_pocock.com.au.pem
# chgrp repro /etc/repro/ssl/domain_key_pocock.com.au.pem
# openssl req -new -key /etc/repro/ssl/domain_key_pocock.com.au.pem -out /etc/repro/ssl/pocock.com.au.csr -subj '/CN=pocock.com.au'
# cat /etc/repro/ssl/pocock.com.au.csr

  • Go to the CACert.org certificate request web form. Cut and paste the contents of the CSR file (the output of the cat command)
  • The CA will now give you a certificate. Install it on the repro server:

# cat > /etc/repro/ssl/domain_cert_pocock.com.au.pem << EOF
-----BEGIN CERTIFICATE-----
MIIF5zCCA8+gAwIBAgIDAQKKMA0GCSqGSIb3DQEBBQUAMFQxFDASBgNVBAoTC0NB
Y2VydCBJbmMuMR4wHAYDVQQLExVodHRwOi8vd3d3LkNBY2VydC5vcmcxHDAaBgNV
BAMTE0NBY2VydCBDbGFzcyAzIFJvb3QwHhcNMTIwODAxMTQzOTA3WhcNMTQwODAx
.
.
.
vcx9+LYSwVLCr33NkDx9zqBn3Qp2ZcaUxOdSo/QxdnE2Wj7J06D309RuDRCxZA7E
cvfc3qE1Q0ESbEOAmN+ZYHhCHZjKe3jNlxED
-----END CERTIFICATE-----
EOF

  • Now edit the repro config file, /etc/repro/repro.config

# vi /etc/repro/repro.config

  • Here is a sample of the config settings that you change from defaults:
IPAddress = 195.8.117.19
UDPPort = 0
TCPPort = 0
TLSPort = 5061
DTLSPort = 0
TLSDomainName = pocock.com.au
TLSClientVerification = Mandatory
TLSUseEmailAsSIP = true
Transport1Interface = 195.8.117.19:5061
Transport1Type = TLS
Transport1TlsDomain = pocock.com.au
Transport1TlsClientVerification = Mandatory
Transport1RecordRouteUri = sip:pocock.com.au;transport=TLS
HttpAdminPassword = admin
RecordRouteUri = sip:pocock.com.au;transport=tls
ForceRecordRouting = true
EnumSuffixes = e164.arpa, sip5060.net, e164.org
DisableOutbound = false
OutboundVersion = 5626
EnableFlowTokens = false
ClientNatDetectionMode = DISABLED
FlowTimer = 0
EnableCertificateAuthenticator = True
DisableAuth = true
  • Things you MUST change in the sample config file above:
    • all instances of the domain pocock.com.au should be replaced with your domain
    • all instances of the IP address 195.8.117.19 should be replaced with your IP address
    • all the passwords (HttpAdminPassword)
  • Notice that UDP and TCP ports are 0 to disable them --- when you rely on TLS authentication, you don't want non-TLS users to connect.
  • Now you can start the proxy
# /etc/init.d/repro start

Getting a client certificate for Jitsi[edit]

  • An email certificate is sufficient - it does not need to have a dedicated SIP extension in the certificate
  • The email address can be in the Common Name (that is how it was for this test) - repro will accept email addresses in 'subjectAltName too
  • You typically want to create the keystore on the machine where you will run Jitsi (or create it on another machine and then copy it to the Jitsi machine)
  • Generate the keypair and the certificate request (CSR) for the CA, set a password (we use mysecret in these examples):
$ keytool -genkey -alias jitsi1 -keyalg RSA -keysize 4096  -keystore  ~/.jitsi.keytool -dname 'CN=daniel@pocock.com.au'

Enter keystore password: Re-enter new password: Enter key password for <jitsi1> (RETURN if same as keystore password):

$ keytool -certreq -alias jitsi1   -file /tmp/jitsi1.csr -keystore ~/.jitsi.keytool -storepass mysecret
$ cat /tmp/jitsi1.csr 
-----BEGIN NEW CERTIFICATE REQUEST-----
MIIEZDCCAkwCAQAwHzEdMBsGA1UEAwwUZGFuaWVsQHBvY29jay5jb20uYXUwggIiMA0GCSqGSIb3
DQEBAQUAA4ICDwAwggIKAoICAQC/ySJt3ZNulDnWG7MtrE+Y6Rkl6ln/ovdefxFdoaBSkg4Bqg8K
.
.
.
cfsbPXSEcdZTYKzPaQpTtkCeWMRKh5R4M61IOd40tANhVbZbf32sZlAeRos7
-----END NEW CERTIFICATE REQUEST-----
  • Log in to CAcert.org. Follow the link to create a Client certificate. Cut and paste the certificate request text into the CAcert.org web form.
  • CACert.org will give you a certificate, put it on the Jitsi machine in a file called /tmp/jitsi1.crt:
# cat > /tmp/jitsi1.crt << EOF
-----BEGIN CERTIFICATE-----
MIIF5zCCA8+gAwIBAgIDAQKKMA0GCSqGSIb3DQEBBQUAMFQxFDASBgNVBAoTC0NB
Y2VydCBJbmMuMR4wHAYDVQQLExVodHRwOi8vd3d3LkNBY2VydC5vcmcxHDAaBgNV
BAMTE0NBY2VydCBDbGFzcyAzIFJvb3QwHhcNMTIwODAxMTQzOTA3WhcNMTQwODAx
.
.
.
vcx9+LYSwVLCr33NkDx9zqBn3Qp2ZcaUxOdSo/QxdnE2Wj7J06D309RuDRCxZA7E
cvfc3qE1Q0ESbEOAmN+ZYHhCHZjKe3jNlxED
-----END CERTIFICATE-----
EOF
  • Import the CA root certificate into the keystore (otherwise keytool won't like the CAcert.org root that signs your client certificate). We assume you are on a Debian system with a copy of the CAcert.org roots in /etc/ssl/certs/cacert.org.pem:
$ keytool -import -alias root -keystore ~/.jitsi.keytool -storepass mysecret -trustcacerts -file /etc/ssl/certs/cacert.org.pem
...
Trust this certificate? [no]:  yes
Certificate was added to keystore
  • Now import the reply from the CA:
$ keytool -importcert -alias jitsi1 -file /tmp/jitsi1.crt -keystore ~/.jitsi.keytool -storepass jitsi1 
Certificate reply was installed in keystore

Setting up the account in the repro web interface[edit]

  • Go to the repro web interface, be default, it listens on port 5080
  • Log in using the password you set in the repro.config file
  • Click Domains and add your domain. Leave the port blank.
  • Click Add User and add your user name (must match the user portion of the email address in your client certificate)
  • At this point, you could check in the database, make sure the user exists in the users table. Check the syslog if it didn't work.

Setting up Jitsi[edit]

  • Go to the Tools menu, click Options, and find the Advanced tab.
  • Click SIP and then remove the check marks next to SSLv2Hello and SSLv3. Only the TLSv1 option should have a check mark.
  • You must restart Jitsi after that change
  • Click TLS Configuration and the Add button.
    • In the Display Name, put some arbitrary name, for example testcert
    • Click the Browse button and locate the file ~/.jitsi.keytool that you created. Click OK to dismiss the file chooser dialog.
    • Click the Type pulldown and choose the jks options
    • In the Password field, put mysecret, or whatever password you used with the keytool command in earlier steps.
    • In the field Alias name in KeyStore, choose jitsi1 or whatever alias name you used with keytool in earlier steps.
    • Now click OK
  • Your certificate details should appear in the table in the Options window
  • Now go to the Accounts tab and click the Add button
    • In the Network menu, choose SIP.
    • Enter the email address as the SIP Id. Leave the Password field blank.
    • Click the Advanced button.
    • Go to the Connection tab
    • In the Client TLS certificate pull down, choose the name that matches the Display Name you chose when you were in the TLS Configuration panel.
    • Click Next and accept the settings
  • Jitsi will try and connect to your repro SIP proxy
  • If it doesn't work, try restarting Jitsi, use the Quit option in the menu - sometimes it doesn't appear to recognise the certificate until after a restart
  • You may get a warning to tell you that Jitsi doesn't trust the server's certificate. For testing, just click the Continue Anyway button.
    • For production use, it is recommended that you either use a CA trusted by the JRE, or add your CA certificate to the JRE's built in keystore.
  • You may get a popup for jks authentication, with a message like The jks server has requested your authentication. In the Password box, insert the password mysecret, or whatever password you used with the keytool command in earlier steps.
  • You should now see the green light that says you are Online

If it doesn't work[edit]

  • In the repro web interface, you can click the REGISTRATIONS menu link to see which users are connected successfully
  • Look at any console output from Jitsi
  • You can run repro from the command line, for example:
# /etc/init/repro stop
# /usr/sbin/repro /etc/repro/repro.config --Daemonize=false --LoggingType=cout --LogLevel=STACK