diff --git a/source/groupdb/mapping_ldb.c b/source/groupdb/mapping_ldb.c
index 68e5b4c..92b2934 100644
--- a/source/groupdb/mapping_ldb.c
+++ b/source/groupdb/mapping_ldb.c
@@ -222,10 +222,10 @@ static bool get_group_map_from_sid(DOM_SID sid, GROUP_MAP *map)
 	if (dn == NULL) goto failed;
 
 	ret = ldb_search(ldb, dn, LDB_SCOPE_BASE, NULL, NULL, &res);
-	talloc_steal(dn, res);
-	if (ret != LDB_SUCCESS || res->count != 1) {
+	if (ret != LDB_SUCCESS || res == NULL || res->count != 1) {
 		goto failed;
 	}
+	talloc_steal(dn, res);
 
 	if (!msg_to_group_map(res->msgs[0], map)) goto failed;
 
@@ -251,8 +251,8 @@ static bool get_group_map_from_gid(gid_t gid, GROUP_MAP *map)
 	if (expr == NULL) goto failed;
 
 	ret = ldb_search(ldb, NULL, LDB_SCOPE_SUBTREE, expr, NULL, &res);
+	if (ret != LDB_SUCCESS || res == NULL || res->count != 1) goto failed;
 	talloc_steal(expr, res);
-	if (ret != LDB_SUCCESS || res->count != 1) goto failed;
 	
 	if (!msg_to_group_map(res->msgs[0], map)) goto failed;
 
@@ -277,8 +277,8 @@ static bool get_group_map_from_ntname(const char *name, GROUP_MAP *map)
 	if (expr == NULL) goto failed;
 
 	ret = ldb_search(ldb, NULL, LDB_SCOPE_SUBTREE, expr, NULL, &res);
+	if (ret != LDB_SUCCESS || res == NULL || res->count != 1) goto failed;
 	talloc_steal(expr, res);
-	if (ret != LDB_SUCCESS || res->count != 1) goto failed;
 	
 	if (!msg_to_group_map(res->msgs[0], map)) goto failed;
 
@@ -343,7 +343,7 @@ static bool enum_group_mapping(const DOM_SID *domsid, enum lsa_SidType sid_name_
 
 	ret = ldb_search(ldb, basedn, LDB_SCOPE_SUBTREE, expr, NULL, &res);
 	talloc_steal(tmp_ctx, res);
-	if (ret != LDB_SUCCESS) goto failed;
+	if (ret != LDB_SUCCESS || res == NULL) goto failed;
 
 	(*pp_rmap) = NULL;
 	*p_num_entries = 0;
@@ -396,7 +396,7 @@ static NTSTATUS one_alias_membership(const DOM_SID *member,
 
 	ret = ldb_search(ldb, NULL, LDB_SCOPE_SUBTREE, expr, attrs, &res);
 	talloc_steal(expr, res);
-	if (ret != LDB_SUCCESS) {
+	if (ret != LDB_SUCCESS || res == NULL) {
 		goto failed;
 	}
 
@@ -517,7 +517,7 @@ static NTSTATUS enum_aliasmem(const DOM_SID *alias, DOM_SID **sids, size_t *num)
 
 	ret = ldb_search(ldb, dn, LDB_SCOPE_BASE, NULL, attrs, &res);
 	talloc_steal(dn, res);
-	if (ret == LDB_SUCCESS && res->count == 0) {
+	if (ret == LDB_SUCCESS && res && res->count == 0) {
 		talloc_free(dn);
 		return NT_STATUS_OK;
 	}