oops
diff --git a/lib/picotls.c b/lib/picotls.c
index 9d58141..5017ded 100644
--- a/lib/picotls.c
+++ b/lib/picotls.c
@@ -1070,7 +1070,7 @@
             ret = PTLS_ALERT_DECODE_ERROR;
             goto Exit;
         }
-        if ((public_name_buf = duplicate_as_str(*src, end - *src)) != NULL) {
+        if ((public_name_buf = duplicate_as_str(*src, end - *src)) == NULL) {
             ret = PTLS_ERROR_NO_MEMORY;
             goto Exit;
         }