From: Kamalesh Babulal <kamalesh.babulal@oracle.com>
Date: Wed, 27 Jul 2022 19:34:45 +0000 (-0600)
Subject: api.c: fix null deference in is_cgrp_ctrl_shared_mnt()
X-Git-Tag: v3.0~8
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c7ad94e3180dc674f049b5e15f84ccdbded2ac61;p=thirdparty%2Flibcgroup.git

api.c: fix null deference in is_cgrp_ctrl_shared_mnt()

Fix explicit null dereferenced warning, reported by Coverity tool:

CID 258306 (#1 of 1): Explicit null dereferenced (FORWARD_NULL).
var_deref_model: Passing null pointer controller_name to
cgroup_find_parent, which dereferences it.

the code path which leads to the null dereference:
cgroup_delete_cgroup_ext()
- cgroup_find_parent()
  - is_cgrp_ctrl_shared_mnt()

is_cgrp_ctrl_shared_mnt(), assumes that the controller_name is non-NULL
but there are changes that, this static function might be called with
NULL controller_name, let's fix it with a check.

Signed-off-by: Kamalesh Babulal <kamalesh.babulal@oracle.com>
Signed-off-by: Tom Hromatka <tom.hromatka@oracle.com>
---

diff --git a/src/api.c b/src/api.c
index ad87a174..4f1059b5 100644
--- a/src/api.c
+++ b/src/api.c
@@ -2734,6 +2734,9 @@ static int is_cgrp_ctrl_shared_mnt(char *controller)
 	int ret = 0;
 	int i;
 
+	if (!controller)
+		return ret;
+
 	pthread_rwlock_rdlock(&cg_mount_table_lock);
 
 	for (i = 0; cg_mount_table[i].name[0] != '\0'; i++) {