pid: use checkpoint_restore_ns_capable() for set_tid

Use the newly introduced capability CAP_CHECKPOINT_RESTORE to allow
using clone3() with set_tid set.

Signed-off-by: Adrian Reber <[email protected]>
Signed-off-by: Nicolas Viennot <[email protected]>
Reviewed-by: Serge Hallyn <[email protected]>
Acked-by: Christian Brauner <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Christian Brauner <[email protected]>

Author: adrianreber

kernel/pid.c

@@ -198,7 +198,7 @@ struct pid *alloc_pid(struct pid_namespace *ns, pid_t *set_tid,
 			if (tid != 1 && !tmp->child_reaper)
 				goto out_free;
 			retval = -EPERM;
-			if (!ns_capable(tmp->user_ns, CAP_SYS_ADMIN))
+			if (!checkpoint_restore_ns_capable(tmp->user_ns))
 				goto out_free;
 			set_tid_size--;
 		}