1 files changed, 55 insertions, 0 deletions
diff --git a/spec/support/helpers/smime_helper.rb b/spec/support/helpers/smime_helper.rb
new file mode 100644
index 00000000000..656b3e196ba
--- /dev/null
+++ b/spec/support/helpers/smime_helper.rb
@@ -0,0 +1,55 @@
+module SmimeHelper
+  include OpenSSL
+
+  INFINITE_EXPIRY = 1000.years
+  SHORT_EXPIRY = 30.minutes
+
+  def generate_root
+    issue(signed_by: nil, expires_in: INFINITE_EXPIRY, certificate_authority: true)
+  end
+
+  def generate_cert(root_ca:, expires_in: SHORT_EXPIRY)
+    issue(signed_by: root_ca, expires_in: expires_in, certificate_authority: false)
+  end
+
+  # returns a hash { key:, cert: } containing a generated key, cert pair
+  def issue(email_address: 'test@example.com', signed_by:, expires_in:, certificate_authority:)
+    key = OpenSSL::PKey::RSA.new(4096)
+    public_key = key.public_key
+
+    subject = if certificate_authority
+                X509::Name.parse("/CN=EU")
+              else
+                X509::Name.parse("/CN=#{email_address}")
+              end
+
+    cert = X509::Certificate.new
+    cert.subject = subject
+
+    cert.issuer = signed_by&.fetch(:cert, nil)&.subject || subject
+
+    cert.not_before = Time.now
+    cert.not_after = expires_in.from_now
+    cert.public_key = public_key
+    cert.serial = 0x0
+    cert.version = 2
+
+    extension_factory = X509::ExtensionFactory.new
+    if certificate_authority
+      extension_factory.subject_certificate = cert
+      extension_factory.issuer_certificate = cert
+      cert.add_extension(extension_factory.create_extension('subjectKeyIdentifier', 'hash'))
+      cert.add_extension(extension_factory.create_extension('basicConstraints', 'CA:TRUE', true))
+      cert.add_extension(extension_factory.create_extension('keyUsage', 'cRLSign,keyCertSign', true))
+    else
+      cert.add_extension(extension_factory.create_extension('subjectAltName', "email:#{email_address}", false))
+      cert.add_extension(extension_factory.create_extension('basicConstraints', 'CA:FALSE', true))
+      cert.add_extension(extension_factory.create_extension('keyUsage', 'digitalSignature,keyEncipherment', true))
+      cert.add_extension(extension_factory.create_extension('extendedKeyUsage', 'clientAuth,emailProtection', false))
+    end
+
+    cert.sign(signed_by&.fetch(:key, nil) || key, Digest::SHA256.new)
+
+    { key: key, cert: cert }
+  end
+end