From: Andrew Bartlett <abartlet@samba.org>
Date: Wed, 2 Aug 2023 02:12:07 +0000 (+1200)
Subject: dsdb: Replace talloc_steal() with a shallow copy and reference in dsdb_paged_results
X-Git-Tag: tevent-0.16.0~1294
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3b51091c20a3c807932bcc986ebb8a676e0ffe6a;p=thirdparty%2Fsamba.git

dsdb: Replace talloc_steal() with a shallow copy and reference in dsdb_paged_results

We should not be stealing caller memory like this, and while a
talloc_reference() is not much better, this combined with a
shallow copy should be a little better in terms of polite
memory management.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15442

Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Stefan Metzmacher <metze@samba.org>
---

diff --git a/source4/dsdb/samdb/ldb_modules/paged_results.c b/source4/dsdb/samdb/ldb_modules/paged_results.c
index a6f2bf22098..83729b02c0b 100644
--- a/source4/dsdb/samdb/ldb_modules/paged_results.c
+++ b/source4/dsdb/samdb/ldb_modules/paged_results.c
@@ -681,6 +681,7 @@ static int paged_search(struct ldb_module *module, struct ldb_request *req)
 		struct ldb_control *ext_ctrl;
 		struct ldb_control **controls;
 		static const char * const attrs[1] = { NULL };
+		void *ref = NULL;
 
 		if (paged_ctrl->size == 0) {
 			return LDB_ERR_OPERATIONS_ERROR;
@@ -739,7 +740,25 @@ static int paged_search(struct ldb_module *module, struct ldb_request *req)
 			return ret;
 		}
 
-		ac->store->expr = talloc_steal(ac->store, req->op.search.tree);
+		/*
+		 * LDB does not have a function to take a full copy of
+		 * this, but at least take a shallow copy
+		 */
+		ac->store->expr = ldb_parse_tree_copy_shallow(ac->store,
+							      req->op.search.tree);
+
+		if (ac->store->expr == NULL) {
+			return ldb_operr(ldb);
+		}
+
+		/*
+		 * As the above is only a shallow copy, take a
+		 * reference to ensure the values are kept around
+		 */
+		ref = talloc_reference(ac->store, req->op.search.tree);
+		if (ref == NULL) {
+			return ldb_module_oom(module);
+		}
 		ac->store->expr_str = ldb_filter_from_tree(ac->store,
 							  req->op.search.tree);
 		if (ac->store->expr_str == NULL) {