when a host is added, we must make sure the app also provides a key *type* even

though we don't use the type in this function

src/knownhost.c

@@ -111,6 +111,10 @@ libssh2_knownhost_add(LIBSSH2_KNOWNHOSTS *hosts,
     if(!entry)
         return rc;
 
+    if(!(typemask & LIBSSH2_KNOWNHOST_KEY_MASK))
+        /* make sure we have a key type set */
+        return LIBSSH2_ERROR_INVAL;
+
     memset(entry, 0, sizeof(struct known_host));
 
     entry->typemask = typemask;