ssl: manually craft invalid SAN extensions in tests

Starting with LibreSSL 3.5, OpenSSL::X509::ExtensionFactory refuses to
create SAN extensions that are not valid according to RFC 6125. While
this behavior makes sense, we need such invalid extensions to test our
own validation routine. Let's construct SAN extensions manually instead.

test/openssl/test_ssl.rb

@@ -835,11 +835,6 @@ def test_post_connection_check_wildcard_san
     #     buzz.example.net, respectively).  ...
     assert_equal(true, OpenSSL::SSL.verify_certificate_identity(
       create_cert_with_san('DNS:baz*.example.com'), 'baz1.example.com'))
-
-    # LibreSSL 3.5.0+ doesn't support other wildcard certificates
-    # (it isn't required to, as RFC states MAY, not MUST)
-    return if libressl?
-
     assert_equal(true, OpenSSL::SSL.verify_certificate_identity(
       create_cert_with_san('DNS:*baz.example.com'), 'foobaz.example.com'))
     assert_equal(true, OpenSSL::SSL.verify_certificate_identity(
@@ -923,11 +918,17 @@ def test_post_connection_check_wildcard_cn
   end
 
   def create_cert_with_san(san)
-    ef = OpenSSL::X509::ExtensionFactory.new
     cert = OpenSSL::X509::Certificate.new
     cert.subject = OpenSSL::X509::Name.parse("/DC=some/DC=site/CN=Some Site")
-    ext = ef.create_ext('subjectAltName', san)
-    cert.add_extension(ext)
+    v = OpenSSL::ASN1::Sequence(san.split(",").map { |item|
+      type, value = item.split(":", 2)
+      case type
+      when "DNS" then OpenSSL::ASN1::IA5String(value, 2, :IMPLICIT)
+      when "IP" then OpenSSL::ASN1::OctetString(IPAddr.new(value).hton, 7, :IMPLICIT)
+      else raise "unsupported"
+      end
+    })
+    cert.add_extension(OpenSSL::X509::Extension.new("subjectAltName", v))
     cert
   end