asn1: avoid truncating OID in OpenSSL::ASN1::ObjectId#oid

OpenSSL::ASN1::ObjectId#oid, which returns the dotted representation of
the OID, is silently truncating the result if it overflows the 128-bytes
buffer. Although it normally won't be more than 127-characters, it'd be
better to avoid. This can be done by checking the return value of
OBJ_obj2txt().

Previous releases of LibreSSL (< 2.5.1) have a bug in OBJ_obj2txt() and
it does not work if the resulting string would be larger than the
buffer. A workaround is added to the test. It should be removed when we
deprecate support for LibreSSL 2.4.

1 files changed, 9 insertions, 0 deletions

diff --git a/test/test_asn1.rb b/test/test_asn1.rb
index e98b9202..61863d02 100644
--- a/test/test_asn1.rb
+++ b/test/test_asn1.rb
@@ -321,6 +321,15 @@ class  OpenSSL::TestASN1 < OpenSSL::TestCase
     }
     assert_raise(OpenSSL::ASN1::ASN1Error) { OpenSSL::ASN1::ObjectId.new("3.0".b).to_der }
     assert_raise(OpenSSL::ASN1::ASN1Error) { OpenSSL::ASN1::ObjectId.new("0.40".b).to_der }
+
+    begin
+      oid = (0...100).to_a.join(".").b
+      obj = OpenSSL::ASN1::ObjectId.new(oid)
+      assert_equal oid, obj.oid
+    rescue OpenSSL::ASN1::ASN1Error
+      pend "OBJ_obj2txt() not working (LibreSSL?)" if $!.message =~ /OBJ_obj2txt/
+      raise
+    end
   end
 
   def test_sequence