wrapper: fix segfault in cgroup_add_value_string

The second and third arguments passed to cgroup_add_value_string() are
of type char * and the user might pass NULL in place of one or both of
the arguments, causing a segfault.  segfault is trigger when the NULL,
argument value is passed to second argument without check, fix it by
checking for NULL before proceeding.

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

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

        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_value_string(cgc, NULL, 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 097a766dd055c41cc6639276d54b8817e512a252)

diff --git a/src/wrapper.c b/src/wrapper.c
index 2038ae787dfdcea2f3f4d5097916d3a7b0a8b3a8..89e9709565ac7d3f818478e27ec985318f66372a 100644 (file)
--- a/src/wrapper.c
+++ b/src/wrapper.c
@@ -209,7 +209,7 @@ int cgroup_add_value_string(struct cgroup_controller *controller, const char *na
        int i;
        struct control_value *cntl_value;
 
-       if (!controller)
+       if (!controller || !name)
                return ECGINVAL;
 
        if (controller->index >= CG_NV_MAX)