Linux sandbox: Allow restricting sched_* on other processes.

sandbox/linux/seccomp-bpf-helpers/syscall_parameters_restrictions.h

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef SANDBOX_LINUX_SECCOMP_BPF_HELPERS_SYSCALL_PARAMETERS_RESTRICTIONS_H_
 #define SANDBOX_LINUX_SECCOMP_BPF_HELPERS_SYSCALL_PARAMETERS_RESTRICTIONS_H_
 
 #include <unistd.h>
 
 #include "build/build_config.h"
@@ skipping 57 matching lines @@
 
 // Restrict |clk_id| for clock_getres(), clock_gettime() and clock_settime().
 // We allow accessing only CLOCK_MONOTONIC, CLOCK_PROCESS_CPUTIME_ID,
 // CLOCK_REALTIME, and CLOCK_THREAD_CPUTIME_ID.  In particular, this disallows
 // access to arbitrary per-{process,thread} CPU-time clock IDs (such as those
 // returned by {clock,pthread}_getcpuclockid), which can leak information
 // about the state of the host OS.
 // On Chrome OS, base::TimeTicks::kClockSystemTrace is also allowed.
 SANDBOX_EXPORT bpf_dsl::ResultExpr RestrictClockID();
 
+// Restricts |pid| for sched_* syscalls which take a pid as the first argument.
+// We only allow calling these syscalls if the pid argument is equal to the pid
+// of the sandboxed process or 0 (indicating the current thread).  The following
+// syscalls are supported:
+//
+// sched_getaffinity(), sched_getattr(), sched_getparam(), sched_getscheduler(),
+// sched_rr_get_interval(), sched_setaffinity(), sched_setattr(),
+// sched_setparam(), sched_setscheduler()
+SANDBOX_EXPORT bpf_dsl::ResultExpr RestrictSchedTarget(pid_t target_pid,
+                                                       int sysno);
+
 }  // namespace sandbox.
 
 #endif  // SANDBOX_LINUX_SECCOMP_BPF_HELPERS_SYSCALL_PARAMETERS_RESTRICTIONS_H_