pyldb: make py_ldb_dn_add_child() a bit less leaky

Signed-off-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>

diff --git a/lib/ldb/pyldb.c b/lib/ldb/pyldb.c
index f2fa5bb3913a082d4e243341e98248171be2a5ad..47b659fc4f465c2b4c0a46e7e8375ca0a834506d 100644 (file)
--- a/lib/ldb/pyldb.c
+++ b/lib/ldb/pyldb.c
@@ -653,22 +653,45 @@ static PyObject *py_ldb_dn_add_child(PyObject *self, PyObject *args)
        PyObject *py_other = NULL;
        struct ldb_dn *dn = NULL;
        struct ldb_dn *other = NULL;
+       TALLOC_CTX *tmp_ctx = NULL;
        bool ok;
 
        PyErr_LDB_DN_OR_RAISE(self, dn);
 
-       if (!PyArg_ParseTuple(args, "O", &py_other))
+       if (!PyArg_ParseTuple(args, "O", &py_other)) {
                return NULL;
+       }
 
-       if (!pyldb_Object_AsDn(NULL, py_other, ldb_dn_get_ldb_context(dn), &other))
+       /*
+        * pyldb_Object_AsDn only uses tmp_ctx if py_other is str/bytes, in
+        * which case it allocates a struct ldb_dn. If py_other is a PyLdbDn,
+        * tmp_ctx is unused and the underlying dn is borrowed.
+        *
+        * The pieces of other are reassembled onto dn using dn itself as a
+        * talloc context (ldb_dn_add_child assumes all dns are talloc
+        * contexts), after which we don't need any temporary DN we made.
+        */
+       tmp_ctx = talloc_new(NULL);
+       if (tmp_ctx == NULL) {
+               PyErr_NoMemory();
                return NULL;
+       }
+
+       ok = pyldb_Object_AsDn(tmp_ctx,
+                              py_other,
+                              ldb_dn_get_ldb_context(dn),
+                              &other);
+       if (!ok) {
+               TALLOC_FREE(tmp_ctx);
+               return NULL;
+       }
 
        ok = ldb_dn_add_child(dn, other);
+       TALLOC_FREE(tmp_ctx);
        if (!ok) {
                PyErr_SetLdbError(PyExc_LdbError, LDB_ERR_OPERATIONS_ERROR, NULL);
                return NULL;
        }
-
        Py_RETURN_TRUE;
 }