[PATCH] SELinux: add security hooks to {get,set}affinity

This patch adds LSM hooks into the setaffinity and getaffinity functions to
enable security modules to control these operations between tasks with
task_setscheduler and task_getscheduler LSM hooks.

Signed-off-by: David Quigley <dpquigl@tycho.nsa.gov>
Acked-by:  Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

kernel/sched.c

@@ -3886,6 +3886,10 @@ long sched_setaffinity(pid_t pid, cpumask_t new_mask)
 			!capable(CAP_SYS_NICE))
 		goto out_unlock;
 
+	retval = security_task_setscheduler(p, 0, NULL);
+	if (retval)
+		goto out_unlock;
+
 	cpus_allowed = cpuset_cpus_allowed(p);
 	cpus_and(new_mask, new_mask, cpus_allowed);
 	retval = set_cpus_allowed(p, new_mask);
@@ -3954,7 +3958,10 @@ long sched_getaffinity(pid_t pid, cpumask_t *mask)
 	if (!p)
 		goto out_unlock;
 
-	retval = 0;
+	retval = security_task_getscheduler(p);
+	if (retval)
+		goto out_unlock;
+
 	cpus_and(*mask, p->cpus_allowed, cpu_online_map);
 
 out_unlock: