Check if a task has existing children or co-threads and refuse to set the container ID if either are present. Failure to check this could permit games where a child scratches its parent's back to work around inheritance and double-setting policy. Signed-off-by: Richard Guy Briggs <rgb@xxxxxxxxxx> --- kernel/auditsc.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/kernel/auditsc.c b/kernel/auditsc.c index 29c8482..a6b0a52 100644 --- a/kernel/auditsc.c +++ b/kernel/auditsc.c @@ -2087,6 +2087,10 @@ static int audit_set_containerid_perm(struct task_struct *task, u64 containerid) /* if we don't have caps, reject */ if (!capable(CAP_AUDIT_CONTROL)) return -EPERM; + /* if task has children or is not single-threaded, deny */ + if (!list_empty(&task->children) || + !(thread_group_leader(task) && thread_group_empty(task))) + return -EPERM; /* if containerid is unset, allow */ if (!audit_containerid_set(task)) return 0; -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe cgroups" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
