Add V4L2 device permissions on x86 CrOS which has ozone flag

content/common/sandbox_linux/bpf_gpu_policy_linux.cc

Index: content/common/sandbox_linux/bpf_gpu_policy_linux.cc
diff --git a/content/common/sandbox_linux/bpf_gpu_policy_linux.cc b/content/common/sandbox_linux/bpf_gpu_policy_linux.cc
index 81d389e2ea2962fe9cfa0bce5113a14e54eb4dc5..d6aa07108b6788f240bda717fee3fb959e119b91 100644
--- a/content/common/sandbox_linux/bpf_gpu_policy_linux.cc
+++ b/content/common/sandbox_linux/bpf_gpu_policy_linux.cc
@@ -69,7 +69,15 @@ inline bool IsArchitectureI386() {
 }
 
 inline bool IsArchitectureArm() {
-#if defined(__arm__)
+#if defined(__arm__) || defined(__aarch64__)
+  return true;
+#else
+  return false;
+#endif
+}
+
+inline bool IsOzone() {
+#if defined(USE_OZONE)
   return true;
 #else
   return false;
@@ -129,6 +137,19 @@ intptr_t GpuSIGSYS_Handler(const struct arch_seccomp_data& args,
   }
 }
 
+std::vector<BrokerFilePermission> GetV4L2GpuWhitelist() {

[wuchengli, 2015/01/05 08:42:44]

Better to pass vector as a function parameter to be consistent with
AddArmGpuWhitelist().

void AddV4L2GpuWhiteList(std::vector<BrokerFilePermission>* permissions)

[henryhsu, 2015/01/05 09:15:30]

Done.

+  std::vector<BrokerFilePermission> permissions;
+  // Device nodes for V4L2 video decode accelerator drivers.
+  static const char kDevVideoDecPath[] = "/dev/video-dec";
+
+  // Device nodes for V4L2 video encode accelerator drivers.
+  static const char kDevVideoEncPath[] = "/dev/video-enc";
+
+  permissions.push_back(BrokerFilePermission::ReadWrite(kDevVideoDecPath));
+  permissions.push_back(BrokerFilePermission::ReadWrite(kDevVideoEncPath));
+  return permissions;
+}
+
 class GpuBrokerProcessPolicy : public GpuProcessPolicy {
  public:
   static sandbox::bpf_dsl::Policy* Create() {
@@ -300,6 +321,11 @@ void GpuProcessPolicy::InitGpuBrokerProcess(
   if (!IsChromeOS()) {
     permissions.push_back(
         BrokerFilePermission::ReadWriteCreateUnlinkRecursive(kDevShm));
+  } else if (IsArchitectureArm() || IsOzone()){

[wuchengli, 2015/01/05 08:42:44]

This is incorrect. From GetGpuProcessSandbox in sandbox_seccomp_bpf_linux.cc,
ARM only calls CrosArmGpuProcessPolicy. I think you need to have
GetV4L2GpuWhitelist in GpuProcessPolicy and CrosArmGpuProcessPolicy can call it.

You can also see GpuProcessPolicy::PreSandboxHook has DCHECK(!chromeos_arm_gpu).

The CL description said it worked on pit. I don't understand why.

[henryhsu, 2015/01/05 09:15:30]

Arm only calls CrosArmGpuProcessPolicy. But it also calls InitGpuBrokerProcess
in CrosArmGpuProcessPolicy::PreSandboxHook. InitGpuBrokerProcess is a class
function of GpuProcessPolicy.

+    std::vector<BrokerFilePermission> v4l2_permissions = GetV4L2GpuWhitelist();
+    for (const auto& perm : v4l2_permissions) {
+      permissions.push_back(perm);
+    }
   }
 
   // Add eventual extra files from permissions_extra.