Add OpenSSL3 support (#1)

* Fix compatibility with OpenSSL 3

* Fix tests

* Further OpenSSL 3 fixes

* Use public_to_pem instead of lower-level ASN1 representation

Author: ClearlyClaire

lib/webpush/encryption.rb

@@ -11,8 +11,7 @@ def encrypt(message, p256dh, auth)
       group_name = 'prime256v1'
       salt = Random.new.bytes(16)
 
-      server = OpenSSL::PKey::EC.new(group_name)
-      server.generate_key
+      server = OpenSSL::PKey::EC.generate(group_name)
       server_public_key_bn = server.public_key.to_bn
 
       group = OpenSSL::PKey::EC::Group.new(group_name)
@@ -74,4 +73,4 @@ def blank?(value)
       value.nil? || value.empty?
     end
   end
-end
+end

lib/webpush/vapid_key.rb

@@ -10,8 +10,7 @@ class VapidKey
     # @return [Webpush::VapidKey] a VapidKey instance for the given public and private keys
     def self.from_keys(public_key, private_key)
       key = new
-      key.public_key = public_key
-      key.private_key = private_key
+      key.set_keys!(public_key, private_key)
 
       key
     end
@@ -20,19 +19,14 @@ def self.from_keys(public_key, private_key)
     #
     # @return [Webpush::VapidKey] a VapidKey instance for the given public and private keys
     def self.from_pem(pem)
-      key = new
-      src = OpenSSL::PKey.read pem
-      key.curve.public_key = src.public_key
-      key.curve.private_key = src.private_key
-
-      key
+      new(OpenSSL::PKey.read pem)
     end
 
     attr_reader :curve
 
-    def initialize
-      @curve = OpenSSL::PKey::EC.new('prime256v1')
-      @curve.generate_key
+    def initialize(pkey = nil)
+      @curve = pkey
+      @curve = OpenSSL::PKey::EC.generate('prime256v1') if @curve.nil?
     end
 
     # Retrieve the encoded elliptic curve public key for VAPID protocol
@@ -57,11 +51,11 @@ def private_key
     end
 
     def public_key=(key)
-      curve.public_key = OpenSSL::PKey::EC::Point.new(group, to_big_num(key))
+      set_keys!(key, nil)
     end
 
     def private_key=(key)
-      curve.private_key = to_big_num(key)
+      set_keys!(nil, key)
     end
 
     def curve_name
@@ -78,16 +72,39 @@ def to_h
     alias to_hash to_h
 
     def to_pem
-      public_key = OpenSSL::PKey::EC.new curve
-      public_key.private_key = nil
-
-      curve.to_pem + public_key.to_pem
+      curve.to_pem + curve.public_to_pem
     end
 
     def inspect
       "#<#{self.class}:#{object_id.to_s(16)} #{to_h.map { |k, v| ":#{k}=#{v}" }.join(' ')}>"
     end
 
+    def set_keys!(public_key = nil, private_key = nil)
+      if public_key.nil?
+        public_key = curve.public_key
+      else
+        public_key = OpenSSL::PKey::EC::Point.new(group, to_big_num(public_key))
+      end
+
+      if private_key.nil?
+        private_key = curve.private_key
+      else
+        private_key = to_big_num(private_key)
+      end
+
+      asn1 = OpenSSL::ASN1::Sequence([
+        OpenSSL::ASN1::Integer.new(1),
+        # Not properly padded but OpenSSL doesn't mind
+        OpenSSL::ASN1::OctetString(private_key.to_s(2)),
+        OpenSSL::ASN1::ObjectId('prime256v1', 0, :EXPLICIT),
+        OpenSSL::ASN1::BitString(public_key.to_octet_string(:uncompressed), 1, :EXPLICIT),
+      ])
+
+      der = asn1.to_der
+
+      @curve = OpenSSL::PKey::EC.new(der)
+    end
+
     private
 
     def to_big_num(key)

spec/webpush/encryption_spec.rb

@@ -4,9 +4,7 @@
   describe '#encrypt' do
     let(:curve) do
       group = 'prime256v1'
-      curve = OpenSSL::PKey::EC.new(group)
-      curve.generate_key
-      curve
+      OpenSSL::PKey::EC.generate(group)
     end
 
     let(:p256dh) do