From: Kamalesh Babulal <kamalesh.babulal@oracle.com>
Date: Fri, 24 Feb 2023 05:35:02 +0000 (+0530)
Subject: wrapper: fix segfault in cgroup_add_controller()
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=371aa7e4c9f30cdeea35e8d96fa870607661b293;p=thirdparty%2Flibcgroup.git

wrapper: fix segfault in cgroup_add_controller()

The second argument passed to cgroup_add_controller() is of type
char * and the user might pass NULL in place of the arguments, causing
a segfault.  segfault is trigger when the NULL, argument values is used
without checks, fix it by checking for NULL before proceeding.

Reproducer:
-----------

int main(void)
{
	struct cgroup_controller *cgc;
	struct cgroup *cgrp;
	int ret;

	cgroup_init();
	if (ret)
		exit(1);

	cgrp = cgroup_new_cgroup("fuzzer");
	if (!cgrp)
		exit(1);

	cgc = cgroup_add_controller(cgrp, "cpu");
	if (!cgc)
		exit(1);

	cgroup_add_controller(cgrp, NULL);

	// should not reach here
	return 0;
}

Signed-off-by: Kamalesh Babulal <kamalesh.babulal@oracle.com>
Signed-off-by: Tom Hromatka <tom.hromatka@oracle.com>
(cherry picked from commit 42436e7e32412c32d2130198fe8a4c0ff48e1d07)
---

diff --git a/src/wrapper.c b/src/wrapper.c
index c97b529e..2038ae78 100644
--- a/src/wrapper.c
+++ b/src/wrapper.c
@@ -63,7 +63,7 @@ struct cgroup_controller *cgroup_add_controller(struct cgroup *cgroup, const cha
 	struct cgroup_controller *controller;
 	int i, ret;
 
-	if (!cgroup)
+	if (!cgroup || !name)
 		return NULL;
 
 	/* Still not sure how to handle the failure here. */