From: Christian Brauner <christian.brauner@ubuntu.com>
Date: Mon, 28 Jun 2021 07:44:20 +0000 (+0200)
Subject: cgroups: verify that hierarchies are non-empty
X-Git-Tag: lxc-5.0.0~152^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=refs%2Fpull%2F3884%2Fhead;p=thirdparty%2Flxc.git

cgroups: verify that hierarchies are non-empty

Fixes: #3881
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
---

diff --git a/src/lxc/cgroups/cgroup.h b/src/lxc/cgroups/cgroup.h
index cb2a9751a..d057957b4 100644
--- a/src/lxc/cgroups/cgroup.h
+++ b/src/lxc/cgroups/cgroup.h
@@ -326,6 +326,9 @@ static inline int prepare_cgroup_ctx(struct cgroup_ops *ops,
 {
 	__u32 idx;
 
+	if (!ops || !ops->hierarchies)
+		return ret_errno(ENOENT);
+
 	for (idx = 0; ops->hierarchies[idx]; idx++) {
 		if (idx >= CGROUP_CTX_MAX_FD)
 			return ret_errno(E2BIG);