Canvas Creates Private-Public Key Pair & Copy into JWK Format

Closes PLAT-3503 & PLAT-3504

Test Plan
- Verify Lti::RSAKeyPair can generate a private and a public key
- Verify the key pair can be read but not modified
- Verify the keys got copied into JWK format correctly

Change-Id: If83edebfbf631815e3078031623d6dead52017ec
Reviewed-on: https://gerrit.instructure.com/154187
Reviewed-by: Marc Alan Phillips <mphillips@instructure.com>
Tested-by: Jenkins
QA-Review: Marc Alan Phillips <mphillips@instructure.com>
Product-Review: Han Ngo <hngo@instructure.com>

lib/lti/jwk_key_pair.rb

@@ -0,0 +1,26 @@
+#
+# Copyright (C) 2018 - present Instructure, Inc.
+#
+# This file is part of Canvas.
+#
+# Canvas is free software: you can redistribute it and/or modify it under
+# the terms of the GNU Affero General Public License as published by the Free
+# Software Foundation, version 3 of the License.
+#
+# Canvas is distributed in the hope that it will be useful, but WITHOUT ANY
+# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+# A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Affero General Public License along
+# with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+module Lti
+  class JWKKeyPair
+    attr_reader :public_key, :private_key
+    def to_jwk
+      time = Time.now.utc.iso8601
+      private_key.to_jwk(kid: time)
+    end
+  end
+end

lib/lti/rsa_key_pair.rb

@@ -0,0 +1,27 @@
+#
+# Copyright (C) 2018 - present Instructure, Inc.
+#
+# This file is part of Canvas.
+#
+# Canvas is free software: you can redistribute it and/or modify it under
+# the terms of the GNU Affero General Public License as published by the Free
+# Software Foundation, version 3 of the License.
+#
+# Canvas is distributed in the hope that it will be useful, but WITHOUT ANY
+# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+# A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Affero General Public License along
+# with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+require 'openssl'
+
+module Lti
+  class RSAKeyPair < JWKKeyPair
+    def initialize(key_size: 256)
+      @private_key = OpenSSL::PKey::RSA.new key_size
+      @public_key = private_key.public_key
+    end
+  end
+end

spec/lib/lti/jwk_key_pair_spec.rb

@@ -0,0 +1,30 @@
+#
+# Copyright (C) 2016 - present Instructure, Inc.
+#
+# This file is part of Canvas.
+#
+# Canvas is free software: you can redistribute it and/or modify it under
+# the terms of the GNU Affero General Public License as published by the Free
+# Software Foundation, version 3 of the License.
+#
+# Canvas is distributed in the hope that it will be useful, but WITHOUT ANY
+# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+# A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Affero General Public License along
+# with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+require 'timecop'
+require File.expand_path(File.dirname(__FILE__) + '/../../spec_helper')
+
+describe Lti::JWKKeyPair do
+  describe "to_jwk" do
+    it 'has the private key in the JWK format' do
+      Timecop.freeze(Time.zone.now) do
+        keys = Lti::RSAKeyPair.new
+        expect(keys.to_jwk).to include(keys.private_key.to_jwk(kid: Time.now.utc.iso8601))
+      end
+    end
+  end
+end

spec/lib/lti/rsa_key_pair_spec.rb

@@ -0,0 +1,43 @@
+#
+# Copyright (C) 2018 - present Instructure, Inc.
+#
+# This file is part of Canvas.
+#
+# Canvas is free software: you can redistribute it and/or modify it under
+# the terms of the GNU Affero General Public License as published by the Free
+# Software Foundation, version 3 of the License.
+#
+# Canvas is distributed in the hope that it will be useful, but WITHOUT ANY
+# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+# A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Affero General Public License along
+# with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+
+require File.expand_path(File.dirname(__FILE__) + '/../../spec_helper')
+
+describe Lti::RSAKeyPair do
+  describe "initialize" do
+    it 'generates a public key of default size 256' do
+      keys = Lti::RSAKeyPair.new
+      expect(/\d+/.match(keys.public_key.to_text())[0]).to eq "256"
+    end
+
+    it 'generates a private key of default size 256' do
+      keys = Lti::RSAKeyPair.new
+      expect(/\d+/.match(keys.private_key.to_text())[0]).to eq "256"
+    end
+
+    it 'generates a public key with specified size' do
+      keys = Lti::RSAKeyPair.new key_size: 2048
+      expect(/\d+/.match(keys.public_key.to_text())[0]).to eq "2048"
+    end
+
+    it 'generates a private key with specified size' do
+      keys = Lti::RSAKeyPair.new key_size: 2048
+      expect(/\d+/.match(keys.private_key.to_text())[0]).to eq "2048"
+    end
+  end
+end