PT-TLS SWIMA Server¶

Installing the strongSwan TNC Software¶

First we have to install some additional Ubuntu packages needed for the strongSwan TNC build

 sudo apt install libsystemd-dev libssl-dev libcurl4-openssl-dev sqlite3 libsqlite3-dev libjson0-dev

Download the lastest strongSwan tarball

wget https://download.strongswan.org/strongswan-5.6.0dr1.tar.bz2

Unpack the tarball

tar xf strongswan-5.6.0dr1.tar.bz2

and change into the strongSwan build directory

cd strongswan-5.6.0dr1

Configure strongSwan with the following options

./configure --prefix=/usr --sysconfdir=/etc --disable-gmp --enable-openssl --enable-tnc-imv --enable-tnc-pdp --enable-tnccs-20 --enable-imv-os --enable-imv-swima --enable-sqlite --enable-curl --disable-stroke --enable-swanctl --enable-systemd

Build and install strongSwan with the commands

make; sudo make install

The following TNC server options have to be configured in /etc/strongswan.conf

charon-systemd {
  journal {
    default = 1
    tnc = 2
    imv = 3
    pts = 2
  }
  syslog {
    auth {
      default = 0
    }
  }
  plugins {
    tnccs-20 {
      max_batch_size = 131056
      max_message_size = 131024
    }
    tnc-pdp {
      server = tnc.example.org
      pt_tls {
        enable = yes
      }
      radius {
        enable = no
      }
    }
  }
}

libtls {
  suites = TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256,TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256
}

libimcv {
  database = sqlite:///etc/pts/config.db
  policy_script = ipsec imv_policy_manager
  plugins {
    imv-swima {
      rest_api {
        uri = https://admin-user:ietf99hackathon@tnc.example.com/api/
        timeout = 360
      }
    }
  }
}

Setting up a Certificate Authority using the strongSwan "pki" Tool¶

The strongSwan pki tool is very powerful and easy to use. First we create a directory where all keys and certificates are going to be stored

  sudo -s
  mkdir /etc/pts
  mkdir /etc/pts/pki
  cd /etc/pts/pki

Then we generate an ECC public key pair for the Root CA and a matching self-signed CA certificate

pki --gen --type ecdsa --size 256 --outform pem > caKey.pem
pki --self --ca --in caKey.pem --type ecdsa --dn "C=CZ, O=IETF, OU=SACM, CN=IETF 99 Prague Hackathon CA" --lifetime 3652 --outform pem > caCert.pem

The CA certificate can be listed with the following command

pki --print --in caCert.pem
  subject:  "C=CZ, O=IETF, OU=SACM, CN=IETF 99 Prague Hackathon CA" 
  issuer:   "C=CZ, O=IETF, OU=SACM, CN=IETF 99 Prague Hackathon CA" 
  validity:  not before Jul 07 08:19:08 2017, ok
             not after  Jul 07 08:19:08 2027, ok (expires in 3651 days)
  serial:    3a:98:52:2e:75:a5:a5:8b
  flags:     CA CRLSign self-signed
  subjkeyId: 81:44:64:84:26:5f:f6:08:80:4a:c9:77:32:0e:b2:78:d0:8f:e5:84
  pubkey:    ECDSA 256 bits
  keyid:     85:94:42:42:d7:40:83:17:98:72:7f:d7:6b:4a:08:51:e8:5b:e0:63
  subjkey:   81:44:64:84:26:5f:f6:08:80:4a:c9:77:32:0e:b2:78:d0:8f:e5:84

pki --req --in serverKey.pem --type ecdsa --dn "C=CZ, O=IETF, OU=SACM, CN=TNC Server" --san "tnc.example.com" --outform pem > serverReq.pem

pki --issue --cakey caKey.pem --cacert caCert.pem --in serverReq.pem --type pkcs10 --flag serverAuth --lifetime 1461 --outform pem > serverCert.pem

pki --print --in serverCert.pem
  subject:  "C=CZ, O=IETF, OU=SACM, CN=TNC Server" 
  issuer:   "C=CZ, O=IETF, OU=SACM, CN=IETF 99 Prague Hackathon CA" 
  validity:  not before Jul 07 09:07:31 2017, ok
             not after  Jul 07 09:07:31 2021, ok (expires in 1460 days)
  serial:    40:53:6a:88:f5:52:50:3b
  altNames:  tnc.example.com
  flags:     serverAuth
  authkeyId: 81:44:64:84:26:5f:f6:08:80:4a:c9:77:32:0e:b2:78:d0:8f:e5:84
  subjkeyId: 9c:83:b7:e9:0a:7d:dd:08:1f:2d:c5:c6:cc:63:c0:3f:96:57:a2:ce
  pubkey:    ECDSA 256 bits
  keyid:     15:91:40:5f:55:58:1f:9c:18:c1:89:6d:47:7c:bd:50:3d:b4:90:a1
  subjkey:   9c:83:b7:e9:0a:7d:dd:08:1f:2d:c5:c6:cc:63:c0:3f:96:57:a2:ce

The server key and the server and CA certificates are needed by the strongSwan TNC server and are therefore copied to the default locations.

cp caCert.pem /etc/swanctl/x509ca
cp serverCert.pem /etc/swanctl/x509
cp serverKey.pem /etc/swanctl/ecdsa