Using SoftHSMv2 Token for StrongSwan

The report includes SoftHSM 2.6.1, StrongSwan configuration, token creation commands, and logs ending in TOKEN_NOT_RECOGNIZED and C_GenerateKeyPair() GENERAL_ERROR. Start by reviewing the linked StrongSwan discussion and checking whether the reported failures can be reproduced with this setup. Done means identifying whether SoftHSM is responsible and documenting a working token configuration or a reproducible defect.

Hi there,

I'm using StrongSwan (IPSec) in the "RoadWarrior"-Scenario. Since StrongSwan offers a PKCS#11 PlugIn, I tried to use the Token from StrongSwan. But I'm receiving this Error:

00[DMN] Starting IKE charon daemon (strongSwan 6.0.0beta6, Linux 6.1.0-18-amd64, x86_64)
00[CFG] PKCS11 module '<name>' lacks library path
00[CFG] loaded PKCS#11 v2.40 library 'hsm-module' (/usr/lib/softhsm/libsofthsm2.so)
00[CFG]   SoftHSM: Implementation of PKCS11 v2.6
00[CFG]   found token in slot 'hsm-module':1807073400 (SoftHSM slot ID 0x6bb5c078)
00[CFG]     my_token (SoftHSM project: SoftHSM v2)
00[CFG]   found token in slot 'hsm-module':1 (SoftHSM slot ID 0x1)
00[CFG]       (SoftHSM project: SoftHSM v2)
00[LIB] plugin 'sha1': failed to load - sha1_plugin_create not found and no plugin file available
00[LIB] plugin 'tpm': failed to load - tpm_plugin_create not found and no plugin file available
00[LIB] providers loaded by OpenSSL: legacy default
00[CFG] install DNS servers in '/etc/resolv.conf'
00[CFG]     loaded untrusted cert 'MyCertificate'
00[CFG] opening session failed: TOKEN_NOT_RECOGNIZED
00[LIB] loaded plugins: charon pkcs11 sha3 random nonce x509 revocation constraints pubkey pkcs1 pkcs7 pgp dnskey sshkey pem openssl pkcs8 xcbc cmac kdf drbg attr kernel-netlink resolve socket-default vici updown xauth-generic
00[JOB] spawning 16 worker threads
00[DMN] executing start script 'creds' (swanctl --load-creds)
04[CFG] module 'hsm-module' does not support hot-plugging, canceled
loaded PKCS#11 v2.40 library 'hsm-module' (/usr/lib/softhsm/libsofthsm2.so)
  SoftHSM: Implementation of PKCS11 v2.6
  found token in slot 'hsm-module':1807073400 (SoftHSM slot ID 0x6bb5c078)
    my_token (SoftHSM project: SoftHSM v2)
  found token in slot 'hsm-module':1 (SoftHSM slot ID 0x1)
      (SoftHSM project: SoftHSM v2)
    loaded untrusted cert 'MyCertificate'
opening session failed: TOKEN_NOT_RECOGNIZED
module 'hsm-module' does not support hot-plugging, canceled
08[CFG] loaded certificate 'C=CH, O=strongswan, CN=moon.strongswan.org'
10[CFG] loaded certificate 'C=CH, O=strongSwan, CN=strongSwan Root CA'
16[CFG] loaded ED25519 private key
12[CFG] found key on PKCS#11 token 'hsm-module':1807073400
12[CFG] loaded RSA private key from token
Segmentation fault (core dumped)
00[DMN] executing start script 'conns' (swanctl --load-conns)
loaded PKCS#11 v2.40 library 'hsm-module' (/usr/lib/softhsm/libsofthsm2.so)
  SoftHSM: Implementation of PKCS11 v2.6
  found token in slot 'hsm-module':1807073400 (SoftHSM slot ID 0x6bb5c078)
    my_token (SoftHSM project: SoftHSM v2)
  found token in slot 'hsm-module':1 (SoftHSM slot ID 0x1)
      (SoftHSM project: SoftHSM v2)
    loaded untrusted cert 'MyCertificate'
opening session failed: TOKEN_NOT_RECOGNIZED
module 'hsm-module' does not support hot-plugging, canceled
11[CFG] added vici connection: IKEv2
Segmentation fault (core dumped)
00[DMN] executing start script 'pools' (swanctl --load-pools)
loaded PKCS#11 v2.40 library 'hsm-module' (/usr/lib/softhsm/libsofthsm2.so)
  SoftHSM: Implementation of PKCS11 v2.6
  found token in slot 'hsm-module':1807073400 (SoftHSM slot ID 0x6bb5c078)
    my_token (SoftHSM project: SoftHSM v2)
  found token in slot 'hsm-module':1 (SoftHSM slot ID 0x1)
      (SoftHSM project: SoftHSM v2)
    loaded untrusted cert 'MyCertificate'
opening session failed: TOKEN_NOT_RECOGNIZED
module 'hsm-module' does not support hot-plugging, canceled
14[CFG] added vici pool mypool: 10.1.0.1, 254 entries
Segmentation fault (core dumped)
03[NET] received packet: from 192.168.254.3[500] to 192.168.254.2[500] (1100 bytes)
03[ENC] parsed IKE_SA_INIT request 0 [ SA KE No N(NATD_S_IP) N(NATD_D_IP) N(FRAG_SUP) N(HASH_ALG) N(REDIR_SUP) V ]
03[IKE] received strongSwan vendor ID
03[IKE] 192.168.254.3 is initiating an IKE_SA
03[CFG] selected proposal: IKE:AES_CBC_128/HMAC_SHA2_256_128/PRF_HMAC_SHA1/MODP_1024
03[CFG] C_GenerateKeyPair() error: GENERAL_ERROR

Using SoftHSM 2.6.1

This is the configuration for StrongSwan:

strongswan.conf:

charon {
  #threads = 1
  # Definiert Skripte, die beim Start von Charon ausgeführt werden. In diesem Fall werden die Befehle swanctl --load-creds, swanctl --load-conns und swanctl --load-pools ausgeführt, um Anmeldeinformationen, Verbindungen und IP-Pools zu laden.
  start-scripts {
     creds = swanctl --load-creds
     conns = swanctl --load-conns
     pools = swanctl --load-pools
  }
  
  #  Definiert die Log-Einstellungen für Charon. In diesem Fall wird das Standard-Log-Level auf 1 gesetzt und die Log-Nachrichten werden an stderr gesendet.
  filelog {
     stderr {
        default = 1
     }
  }
   
  send_vendor_id = yes
  prefer_configured_proposals = no
  fragment_size = 1480
  max_packet = 30000  
	load_modular = yes
  nonce_plugins = random
	plugins {
		include strongswan.d/charon/*.conf
    vici {
      load = yes
    }
    random {
      # Enable the plugin
      load = yes
    }
    sha1 {
      # Enable the plugin
      load = yes
    }

    sha3 {
      # Enable the plugin
      load = yes
    }
    
    socket-default {
      # Enable the plugin
      use = netkey
    }

    openssl {
      # Enable the plugin
      load = yes
      path = /usr/lib/x86_64-linux-gnu/ruby/3.1.0/openssl.so
    }
	}
}

swanctl {
  load = pem pkcs11 x509 revocation constraints pubkey openssl random
}

include strongswan.d/*.conf

libstrongswan {
  plugins {
    pkcs11 {
      use_dh = true
      use_ecc = true
      use_pubkey = true
      
      modules {
        hsm-module {
          path = /usr/lib/softhsm/libsofthsm2.so
        }
      }
    }
  }
}

swanctl.conf

connections {
	IKEv2 {
		fragmentation=yes
		keyingtries=0
		reauth_time=0s
		rekey_time=1d
		version=2
		remote_addrs=192.168.254.3
		local_addrs=192.168.254.2
		local_port=500
		remote_port=500
		vips=0.0.0.0
		proposals=aes128-sha256-prfsha1-modp1024, default
		dpd_delay=180
		pools = mypool
		children {
			IKEv2 {
				local_ts  = 10.1.0.0/16
				remote_ts = 0.0.0.0/0
			}
		}
		local {
			auth = pubkey
			certs = myCert.pem
			id = moon.strongswan.org
		}
		remote {
			auth = pubkey
		}
	}
}

pools {
    mypool {
        addrs = 10.1.0.1-10.1.0.254
    }
}

authorities {
	myca {
		cacert=caCert.pem
	}
}
secrets {
	privateKey{
			file=privateKey.pem
	}
	tokenSofthsm {
			handle=4142
			# SLOT_ID gets replaced automatically
			slot=SLOT_ID
			module=hsm-module
			pin=2345
	}
}

This is how the Token is created:

softhsm2-util --init-token \
              --slot 0 \
              --free \
              --label "my_token" \
              --pin 2345 \
              --so-pin 2345 \
              | cut -d ' ' -f11 > /id_file && \
\
export LD_LIBRARY_PATH=/usr/local/lib/:$LD_LIBRARY_PATH && \
\
pkcs11-tool --module /usr/lib/softhsm/libsofthsm2.so \
            -l -k \
            --key-type rsa:2048 \
            --id 4142 \
            --label "aeskey" \
            --pin 2345 \
            --usage-decrypt \
            --usage-sign \
            --extractable && \ 
\
export PKCS11_MODULE_PATH=/usr/lib/softhsm/libsofthsm2.so && \
\
openssl req \
          -new \
          -keyform engine \
          -engine pkcs11 \
          -key slot_$(cat /id_file)-id_4142 \
          -passin pass:2345 \
          -out certificate_request.csr \
          -subj "/C=DE/ST=Unknown/L=Unknown/O=MeineFirma/OU=IT/CN=example.com/[email protected]" \
          -nodes \
          -addext "keyUsage = digitalSignature, keyEncipherment" && \
          \
openssl x509 \
          -req \
          -days 365 \
          -in certificate_request.csr \
          -engine pkcs11 \
          -keyform engine \
          -key slot_$(cat /id_file)-id_4142 \
          -passin pass:2345 \
          -out certificate.crt && \
\
pkcs11-tool --module /usr/lib/softhsm/libsofthsm2.so \
            --login \
            --pin 2345 \
            --write-object certificate.crt \
            --type cert \
            --label "MyCertificate"

There is also a Ticket in StrongSwan-Project: https://github.com/strongswan/strongswan/discussions/2248

Please advise,
I'm not sure what leads to this error and how to fix this.
How should the Token be configured that StrongSwan can use it?