[Android] Define a baseline seccomp-bpf sandbox policy.

content/renderer/renderer_main_platform_delegate_android.cc

Index: content/renderer/renderer_main_platform_delegate_android.cc
diff --git a/content/renderer/renderer_main_platform_delegate_android.cc b/content/renderer/renderer_main_platform_delegate_android.cc
index 4a19706360269bd76526fc348869c5c37775a198..0da47c3aca847a9dbd38b2293127f8f085a49e32 100644
--- a/content/renderer/renderer_main_platform_delegate_android.cc
+++ b/content/renderer/renderer_main_platform_delegate_android.cc
@@ -3,7 +3,14 @@
 // found in the LICENSE file.
 
 #include "content/renderer/renderer_main_platform_delegate.h"
+
 #include "base/logging.h"
+#include "base/rand_util.h"
+#include "base/sys_info.h"
+#include "sandbox/linux/seccomp-bpf-helpers/baseline_policy_android.h"
+#include "sandbox/linux/seccomp-bpf/sandbox_bpf.h"
+#include "third_party/skia/include/ports/SkFontConfigInterface.h"
+#include "v8/include/v8.h"
 
 #ifdef ENABLE_VTUNE_JIT_INTERFACE
 #include "content/public/common/content_switches.h"
@@ -12,6 +19,28 @@
 
 namespace content {
 
+namespace {
+
+bool GenerateEntropy(unsigned char* buffer, size_t length) {
+  base::RandBytes(buffer, length);
+  return true;
+}
+
+void PreSandboxWarmUp() {
+  base::RandUint64();
+
+  base::SysInfo::AmountOfPhysicalMemory();
+  base::SysInfo::MaxSharedMemorySize();
+  base::SysInfo::NumberOfProcessors();
+
+  v8::V8::SetEntropySource(&GenerateEntropy);
+  v8::V8::Initialize();
+
+  SkFontConfigInterface::GetSingletonDirectInterface();
+}
+
+}  // namespace
+
 RendererMainPlatformDelegate::RendererMainPlatformDelegate(
     const MainFunctionParams& parameters)
     : parameters_(parameters) {
@@ -36,7 +65,15 @@ bool RendererMainPlatformDelegate::InitSandboxTests(bool no_sandbox) {
 }
 
 bool RendererMainPlatformDelegate::EnableSandbox() {
-  return true;
+  PreSandboxWarmUp();
+
+  sandbox::SandboxBPF sandbox;
+  sandbox.SetSandboxPolicy(new sandbox::BaselinePolicyAndroid);
+  sandbox.StartSandbox();
+  bool enabled = sandbox.SupportsSeccompSandbox(-1) ==
+      sandbox::SandboxBPF::STATUS_ENABLED;
+  CHECK(enabled);
+  return enabled;
 }
 
 void RendererMainPlatformDelegate::RunSandboxTests(bool no_sandbox) {