diff --git a/lib/hx509/ks_p11.c b/lib/hx509/ks_p11.c
index 402683b27..a21d84b03 100644
--- a/lib/hx509/ks_p11.c
+++ b/lib/hx509/ks_p11.c
@@ -730,7 +730,8 @@ collect_cert(struct p11_module *p, struct p11_slot *slot,
     if ((CK_LONG)query[2].ulValueLen != -1) {
 	char *str;
 
-	asprintf(&str, "%.*s", (int)query[2].ulValueLen, query[2].pValue);
+	asprintf(&str, "%.*s",
+		 (int)query[2].ulValueLen, (char *)query[2].pValue);
 	if (str) {
 	    hx509_cert_set_friendly_name(cert, str);
 	    free(str);