ossl_x509name.c: null-terminate field name

* ext/openssl/ossl_x509name.c (ossl_x509name_add_entry): field
  name of X509_NAME_add_entry_by_txt() must be NULL-terminated.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45626 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ext/openssl/ossl_x509name.c

@@ -183,13 +183,14 @@ VALUE ossl_x509name_add_entry(int argc, VALUE *argv, VALUE self)
 {
     X509_NAME *name;
     VALUE oid, value, type;
+    const char *oid_name;
 
     rb_scan_args(argc, argv, "21", &oid, &value, &type);
-    StringValue(oid);
+    oid_name = StringValueCStr(oid);
     StringValue(value);
     if(NIL_P(type)) type = rb_aref(OBJECT_TYPE_TEMPLATE, oid);
     GetX509Name(self, name);
-    if (!X509_NAME_add_entry_by_txt(name, RSTRING_PTR(oid), NUM2INT(type),
+    if (!X509_NAME_add_entry_by_txt(name, oid_name, NUM2INT(type),
 		(const unsigned char *)RSTRING_PTR(value), RSTRING_LENINT(value), -1, 0)) {
 	ossl_raise(eX509NameError, NULL);
     }