Class: PedicelPay::Backend

Inherits:
Object
  • Object
show all
Defined in:
lib/pedicel-pay/backend.rb

Constant Summary collapse

Error = 
Class.new(PedicelPay::Error)
CertificateError = 
Class.new(PedicelPay::Backend::Error)
KeyError = 
Class.new(PedicelPay::Backend::Error)

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(ca_key: nil, ca_certificate: nil, intermediate_key: nil, intermediate_certificate: nil, leaf_key: nil, leaf_certificate: nil) ⇒ Backend

Returns a new instance of Backend.



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# File 'lib/pedicel-pay/backend.rb', line 16

def initialize(ca_key: nil,           ca_certificate: nil,
               intermediate_key: nil, intermediate_certificate: nil,
               leaf_key: nil,         leaf_certificate: nil)
  @ca_key         = ca_key
  @ca_certificate = ca_certificate

  @intermediate_key         = intermediate_key
  @intermediate_certificate = intermediate_certificate

  @leaf_key         = leaf_key
  @leaf_certificate = leaf_certificate
end

Instance Attribute Details

#ca_certificate ⇒ Object

Returns the value of attribute ca_certificate.



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# File 'lib/pedicel-pay/backend.rb', line 11

def ca_certificate
  @ca_certificate
end

#ca_key ⇒ Object

Returns the value of attribute ca_key.



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# File 'lib/pedicel-pay/backend.rb', line 11

def ca_key
  @ca_key
end

#intermediate_certificate ⇒ Object

Returns the value of attribute intermediate_certificate.



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# File 'lib/pedicel-pay/backend.rb', line 11

def intermediate_certificate
  @intermediate_certificate
end

#intermediate_key ⇒ Object

Returns the value of attribute intermediate_key.



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# File 'lib/pedicel-pay/backend.rb', line 11

def intermediate_key
  @intermediate_key
end

#leaf_certificate ⇒ Object

Returns the value of attribute leaf_certificate.



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# File 'lib/pedicel-pay/backend.rb', line 11

def leaf_certificate
  @leaf_certificate
end

#leaf_key ⇒ Object

Returns the value of attribute leaf_key.



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# File 'lib/pedicel-pay/backend.rb', line 11

def leaf_key
  @leaf_key
end

Class Method Details

.generate(config: PedicelPay.config) ⇒ Object 



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# File 'lib/pedicel-pay/backend.rb', line 148

def self.generate(config: PedicelPay.config)
  ck, cc = generate_ca(config: config)

  ik, ic = generate_intermediate(ca_key: ck, ca_certificate: cc, config: config)

  lk, lc = generate_leaf(intermediate_key: ik, intermediate_certificate: ic, config: config)

  new(ca_key: ck, ca_certificate: cc,
      intermediate_key: ik, intermediate_certificate: ic,
      leaf_key: lk, leaf_certificate: lc)
end

.generate_ca(config: PedicelPay.config) ⇒ Object 



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# File 'lib/pedicel-pay/backend.rb', line 160

def self.generate_ca(config: PedicelPay.config)
  key = OpenSSL::PKey::EC.new(PedicelPay::EC_CURVE)
  key.generate_key

  cert = OpenSSL::X509::Certificate.new
  cert.version = 2 # https://www.ietf.org/rfc/rfc5280.txt -> Section 4.1, search for "v3(2)".
  cert.serial = 1
  cert.subject = config[:subject][:ca]
  cert.issuer = cert.subject # Self-signed
  cert.public_key = PedicelPay::Helper.ec_key_to_pkey_public_key(key)
  cert.not_before = config[:valid].min
  cert.not_after = config[:valid].max

  ef = OpenSSL::X509::ExtensionFactory.new
  ef.subject_certificate = cert
  ef.issuer_certificate = cert
  cert.add_extension(ef.create_extension('basicConstraints','CA:TRUE',true))
  cert.add_extension(ef.create_extension('keyUsage','keyCertSign, cRLSign', true))
  cert.add_extension(ef.create_extension('subjectKeyIdentifier','hash',false))
  cert.add_extension(ef.create_extension('authorityKeyIdentifier','keyid:always',false))
  cert.sign(key, OpenSSL::Digest::SHA256.new)

  [key, cert]
end

.generate_intermediate(ca_key:, ca_certificate:, config: PedicelPay.config) ⇒ Object 



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# File 'lib/pedicel-pay/backend.rb', line 185

def self.generate_intermediate(ca_key:, ca_certificate:, config: PedicelPay.config)
  key = OpenSSL::PKey::EC.new(PedicelPay::EC_CURVE)
  key.generate_key

  cert = OpenSSL::X509::Certificate.new
  # https://www.ietf.org/rfc/rfc5280.txt -> Section 4.1, search for "v3(2)".
  cert.version = 2
  cert.serial = 1
  cert.subject = config[:subject][:intermediate]
  cert.issuer = ca_certificate.subject
  cert.public_key = PedicelPay::Helper.ec_key_to_pkey_public_key(key)
  cert.not_before = config[:valid].min
  cert.not_after = config[:valid].max

  ef = OpenSSL::X509::ExtensionFactory.new
  ef.subject_certificate = cert
  ef.issuer_certificate = ca_certificate

  # According to https://tools.ietf.org/html/rfc5280#section-4.2.1.9,
  # CA:TRUE must be set in order to allow signing using this intermediate
  # certificate.
  cert.add_extension(ef.create_extension('basicConstraints', 'CA:TRUE', true))

  cert.add_extension(ef.create_extension('keyUsage', 'keyCertSign, cRLSign', true))
  cert.add_extension(ef.create_extension('subjectKeyIdentifier', 'hash', false))

  cert.add_extension(OpenSSL::X509::Extension.new(config[:oid][:intermediate_certificate], ''))

  cert.sign(ca_key, OpenSSL::Digest::SHA256.new)

  [key, cert]
end

.generate_leaf(intermediate_key:, intermediate_certificate:, config: PedicelPay.config) ⇒ Object 



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# File 'lib/pedicel-pay/backend.rb', line 218

def self.generate_leaf(intermediate_key:, intermediate_certificate:, config: PedicelPay.config)
  key = OpenSSL::PKey::EC.new(PedicelPay::EC_CURVE)
  key.generate_key

  cert = OpenSSL::X509::Certificate.new
  cert.version = 2 # https://www.ietf.org/rfc/rfc5280.txt -> Section 4.1, search for "v3(2)".
  cert.serial = 1
  cert.subject = config[:subject][:leaf]
  cert.issuer = intermediate_certificate.subject
  cert.public_key = PedicelPay::Helper.ec_key_to_pkey_public_key(key)
  cert.not_before = config[:valid].min
  cert.not_after = config[:valid].max

  ef = OpenSSL::X509::ExtensionFactory.new
  ef.subject_certificate = cert
  ef.issuer_certificate = intermediate_certificate
  cert.add_extension(ef.create_extension('keyUsage','digitalSignature', true))
  cert.add_extension(ef.create_extension('subjectKeyIdentifier','hash',false))

  cert.add_extension(OpenSSL::X509::Extension.new(config[:oid][:leaf_certificate], ''))

  cert.sign(intermediate_key, OpenSSL::Digest::SHA256.new)

  [key, cert]
end

.generate_shared_secret_and_ephemeral_pubkey(recipient:) ⇒ Object 



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# File 'lib/pedicel-pay/backend.rb', line 132

def self.generate_shared_secret_and_ephemeral_pubkey(recipient:)
  pubkey = case recipient
           when Client
             OpenSSL::PKey::EC.new(recipient.certificate.public_key).public_key
           when OpenSSL::X509::Certificate
             OpenSSL::PKey::EC.new(recipient.public_key).public_key
           when OpenSSL::PKey::EC::Point
             recipient
           else raise ArgumentError, 'invalid recipient'
           end

  ephemeral_seckey = OpenSSL::PKey::EC.new(PedicelPay::EC_CURVE).generate_key

  [ephemeral_seckey.dh_compute_key(pubkey), ephemeral_seckey.public_key]
end

Instance Method Details

#encrypt(token, recipient:, shared_secret: nil, ephemeral_pubkey: nil) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/pedicel-pay/backend.rb', line 64

def encrypt(token, recipient:, shared_secret: nil, ephemeral_pubkey: nil)
  raise ArgumentError, 'invalid token' unless token.is_a?(Token)

  if shared_secret && ephemeral_pubkey
    # Use them. No check that they come from the same ephemeral secret key.
  elsif shared_secret.nil? ^ ephemeral_pubkey.nil?
    raise ArgumentError, "'shared_secret' and 'ephemeral_pubkey' must be supplied together"
  else # None of shared_secret or ephemeral_pubkey is supplied.
    shared_secret, ephemeral_pubkey = self.class.generate_shared_secret_and_ephemeral_pubkey(recipient: recipient)
  end

  symmetric_key = Pedicel::EC.symmetric_key(shared_secret: shared_secret, merchant_id: Helper.merchant_id(recipient))

  token.encrypted_data = Helper.encrypt(
    data: token.unencrypted_data.to_json,
    key: symmetric_key
  )

  token.header.ephemeral_pubkey = ephemeral_pubkey
  token.update_pubkey_hash(recipient: recipient)

  token
end

#encrypt_and_sign(token, recipient:, shared_secret: nil, ephemeral_pubkey: nil) ⇒ Object 



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# File 'lib/pedicel-pay/backend.rb', line 57

def encrypt_and_sign(token, recipient:, shared_secret: nil, ephemeral_pubkey: nil)
  encrypt(token, recipient: recipient, shared_secret: shared_secret, ephemeral_pubkey: ephemeral_pubkey)
  sign(token)

  token
end

#generate_client(valid: PedicelPay.config[:valid]) ⇒ Object 



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# File 'lib/pedicel-pay/backend.rb', line 29

def generate_client(valid: PedicelPay.config[:valid])
  client = PedicelPay::Client.new(ca_certificate_pem: ca_certificate.to_pem)
  client.generate_key

  client.ca_certificate_pem = ca_certificate.to_pem
  client.certificate = sign_csr(client.generate_csr, valid: valid)

  client
end

#sign(token, certificate: leaf_certificate, key: leaf_key, replace: true) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/pedicel-pay/backend.rb', line 88

def sign(token, certificate: leaf_certificate, key: leaf_key, replace: true)
  raise ArgumentError, 'token has no encrypted_data' unless token.encrypted_data
  raise ArgumentError, 'token has no ephemeral_pubkey' unless token.header.ephemeral_pubkey

  message = [
    Helper.ec_key_to_pkey_public_key(token.header.ephemeral_pubkey).to_der,
    token.encrypted_data,
    token.header.transaction_id,
    token.header.data_hash
  ].compact.join

  signature = OpenSSL::PKCS7.sign(
    certificate,
    key,
    message,
    [intermediate_certificate, ca_certificate], # Chain.
    OpenSSL::PKCS7::BINARY # Handle 0x00 correctly.
  )

  # Check that the newly created signature is good.
  flags = \
    # https://wiki.openssl.org/index.php/Manual:PKCS7_verify(3)#VERIFY_PROCESS
    OpenSSL::PKCS7::NOCHAIN  | # Ignore certs in the message.
    OpenSSL::PKCS7::NOINTERN   # Only look at the supplied certificate.
  trust_store = OpenSSL::X509::Store.new
  trust_store.add_cert(ca_certificate).add_cert(intermediate_certificate)
  unless signature.verify([certificate], trust_store, message, flags)
    fail 'signature is wrong'
  end

  if replace
    # Just replace token.signature.
  else
    if token.signature # Already signed.
      existing_signature = OpenSSL::PKCS7.new(Base64.strict_decode64(token.signature))
      signature = existing_signature.add_signer(signature.signers.first)
    end
  end

  token.signature = Base64.strict_encode64(signature.to_der)

  token
end

#sign_csr(csr, valid: PedicelPay.config[:valid]) ⇒ Object 



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# File 'lib/pedicel-pay/backend.rb', line 39

def sign_csr(csr, valid: PedicelPay.config[:valid])
  cert = OpenSSL::X509::Certificate.new
  cert.version = 2
  cert.serial = 1
  cert.not_before = valid.min
  cert.not_after = valid.max
  cert.subject = PedicelPay.config[:subject][:client]
  cert.public_key = csr.public_key
  cert.issuer = intermediate_certificate.issuer
  cert.sign(intermediate_key, OpenSSL::Digest::SHA256.new)

  merchant_id_hex = Helper.bytestring_to_hex(PedicelPay.config[:random].bytes(32))

  cert.add_extension(OpenSSL::X509::Extension.new(PedicelPay.config[:oid][:merchant_identifier_field], merchant_id_hex))

  cert
end

#validate ⇒ Object 



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# File 'lib/pedicel-pay/backend.rb', line 244

def validate
  validate_ca
  validate_intermediate
  validate_leaf

  true
end

#validate_ca ⇒ Object

Raises:



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# File 'lib/pedicel-pay/backend.rb', line 252

def validate_ca
  raise KeyError, 'ca private key not valid for ca certificate' unless ca_certificate.check_private_key(ca_key)

  raise CertificateError, 'ca certificate is not self-signed' unless ca_certificate.verify(ca_key)

  true
end

#validate_intermediate ⇒ Object

Raises:



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# File 'lib/pedicel-pay/backend.rb', line 260

def validate_intermediate
  raise KeyError, 'intermediate private key not valid for intermediate certificate' unless intermediate_certificate.check_private_key(intermediate_key)

  raise CertificateError, 'intermediate certificate not signed by ca' unless intermediate_certificate.verify(ca_key)

  true
end

#validate_leaf ⇒ Object

Raises:



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# File 'lib/pedicel-pay/backend.rb', line 268

def validate_leaf
  raise KeyError, 'leaf private key not valid for leaf certificate' unless leaf_certificate.check_private_key(leaf_key)

  raise CertificateError, 'leaf certificate not signed by intermediate' unless leaf_certificate.verify(intermediate_key)

  true
end