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

content/common/sandbox_linux/android/sandbox_bpf_base_policy_android.cc

 // Copyright 2014 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 "content/common/sandbox_linux/android/sandbox_bpf_base_policy_android.h"
 
 #include <sys/syscall.h>
 #include <sys/types.h>
 
 #include "sandbox/linux/bpf_dsl/bpf_dsl.h"
 
 using sandbox::bpf_dsl::Allow;
 using sandbox::bpf_dsl::ResultExpr;
 
 namespace content {
 
 SandboxBPFBasePolicyAndroid::SandboxBPFBasePolicyAndroid()
     : SandboxBPFBasePolicy() {}
 
 SandboxBPFBasePolicyAndroid::~SandboxBPFBasePolicyAndroid() {}
 
 ResultExpr SandboxBPFBasePolicyAndroid::EvaluateSyscall(int sysno) const {
   bool override_and_allow = false;
 
   switch (sysno) {
     // TODO(rsesek): restrict clone parameters.
     case __NR_clone:
     case __NR_epoll_pwait:
     case __NR_flock:
+#if defined(__x86_64__) || defined(__aarch64__)
+    case __NR_newfstatat:
+#elif defined(__i386__) || defined(__arm__) || defined(__mips__)
+    case __NR_fstatat64:
+#endif
     case __NR_getpriority:
     case __NR_ioctl:
     case __NR_mremap:
     // File system access cannot be restricted with seccomp-bpf on Android,
     // since the JVM classloader and other Framework features require file
     // access. It may be possible to restrict the filesystem with SELinux.
     // Currently we rely on the app/service UID isolation to create a
     // filesystem "sandbox".
 #if !ARCH_CPU_ARM64

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

Do you mind fixing this (to #if !defined()) as drive-by?

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

Done.

     case __NR_open:
 #endif
     case __NR_openat:
     case __NR_pread64:
     case __NR_rt_sigtimedwait:
     case __NR_setpriority:
+    case __NR_set_tid_address:
     case __NR_sigaltstack:
 #if defined(__i386__) || defined(__arm__)
     case __NR_ugetrlimit:
 #else
     case __NR_getrlimit:
 #endif
     case __NR_uname:
       override_and_allow = true;
       break;
   }
 
   if (override_and_allow)
     return Allow();
 
   return SandboxBPFBasePolicy::EvaluateSyscall(sysno);
 }
 
 }  // namespace content