Class: Gitlab::Email::Smime::Signer

Inherits:
Object
  • Object
show all
Defined in:
lib/gitlab/email/smime/signer.rb

Overview

Tooling for signing and verifying data with SMIME

Class Method Summary collapse

Class Method Details

.sign(cert:, key:, ca_certs: nil, data:) ⇒ Object

The `ca_certs` parameter, if provided, is an array of CA certificates that will be attached in the signature together with the main `cert`. This will be typically intermediate CAs


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# File 'lib/gitlab/email/smime/signer.rb', line 13

def self.sign(cert:, key:, ca_certs: nil, data:)
  signed_data = OpenSSL::PKCS7.sign(cert, key, data, Array.wrap(ca_certs), OpenSSL::PKCS7::DETACHED)
  OpenSSL::PKCS7.write_smime(signed_data)
end

.verify_signature(ca_certs: nil, signed_data:) ⇒ Object

Return nil if data cannot be verified, otherwise the signed content data

Be careful with the `ca_certs` parameter, it will implicitly trust all the CAs in the array by creating a trusted store, stopping validation at the first match This is relevant when using intermediate CAs, `ca_certs` should only include the trusted, root CA


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# File 'lib/gitlab/email/smime/signer.rb', line 24

def self.verify_signature(ca_certs: nil, signed_data:)
  store = OpenSSL::X509::Store.new
  store.set_default_paths
  Array.wrap(ca_certs).compact.each { |ca_cert| store.add_cert(ca_cert) }

  signed_smime = OpenSSL::PKCS7.read_smime(signed_data)

  # The S/MIME certificate(s) are included in the message and the trusted
  # CAs are in the store parameter, so we pass no certs as parameters
  # to `PKCS7.verify`
  # See https://www.openssl.org/docs/manmaster/man3/PKCS7_verify.html
  signed_smime if signed_smime.verify(nil, store)
end