[Android] Get renderers working again under seccomp-bpf.

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

 // 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.
 
 #include "sandbox/linux/seccomp-bpf-helpers/syscall_parameters_restrictions.h"
 
 #include <errno.h>
 #include <fcntl.h>
 #include <fcntl.h>
 #include <linux/futex.h>
@@ skipping 22 matching lines @@
 #include "sandbox/linux/services/linux_syscalls.h"
 
 #if defined(OS_ANDROID)
 
 #include "sandbox/linux/services/android_futex.h"
 
 #if !defined(F_DUPFD_CLOEXEC)
 #define F_DUPFD_CLOEXEC (F_LINUX_SPECIFIC_BASE + 6)
 #endif
 
+// https://android.googlesource.com/platform/bionic/+/lollipop-release/libc/private/bionic_prctl.h
+#if !defined(PR_SET_VMA)
+#define PR_SET_VMA 0x53564d41
+#endif
+
+// https://android.googlesource.com/platform/system/core/+/lollipop-release/libcutils/sched_policy.c
+#if !defined(PR_SET_TIMERSLACK_PID)
+#define PR_SET_TIMERSLACK_PID 41
+#endif
+
 #endif  // defined(OS_ANDROID)
 
 #if defined(__arm__) && !defined(MAP_STACK)
 #define MAP_STACK 0x20000  // Daisy build environment has old headers.
 #endif
 
 #if defined(__mips__) && !defined(MAP_STACK)
 #define MAP_STACK 0x40000
 #endif
 namespace {
@@ skipping 69 matching lines @@
       .Else(CrashSIGSYSClone());
 }
 
 ResultExpr RestrictPrctl() {
   // Will need to add seccomp compositing in the future. PR_SET_PTRACER is
   // used by breakpad but not needed anymore.
   const Arg<int> option(0);
   return Switch(option)
       .CASES((PR_GET_NAME, PR_SET_NAME, PR_GET_DUMPABLE, PR_SET_DUMPABLE),
              Allow())
+#if defined(OS_ANDROID)
+      .CASES((PR_SET_VMA, PR_SET_TIMERSLACK_PID), Allow())

[jln (very slow on Chromium), 2014/12/04 01:35:38]

Any reasonable way to add a unit test here?

Either call set_sched_policy() or figure out what the common caller is (any
thread creation?)

[Robert Sesek, 2014/12/04 17:56:59]

No, I tried. There's no common caller, and most callers are in JNI functions.
set_sched_policy() isn't in the NDK either (it's defined in cutils, which is
private). Similar for all use of PR_SET_VMA.

I can test __NR_set_tid_address, but that's not too interesting, and it's in the
//content-level policy, rather than //sandbox :|

+#endif
       .Default(CrashSIGSYSPrctl());
 }
 
 ResultExpr RestrictIoctl() {
   const Arg<int> request(1);
   return Switch(request).CASES((TCGETS, FIONREAD), Allow()).Default(
       CrashSIGSYSIoctl());
 }
 
 ResultExpr RestrictMmapFlags() {
@@ skipping 143 matching lines @@
       return CrashSIGSYS();
   }
 }
 
 ResultExpr RestrictPrlimit64(pid_t target_pid) {
   const Arg<pid_t> pid(0);
   return If(pid == 0 || pid == target_pid, Allow()).Else(CrashSIGSYS());
 }
 
 }  // namespace sandbox.