ozone gbm: whitelist 3 DRM ioctl code for native GpuMemoryBuffer.

content/common/sandbox_linux/bpf_renderer_policy_linux.cc

Index: content/common/sandbox_linux/bpf_renderer_policy_linux.cc
diff --git a/content/common/sandbox_linux/bpf_renderer_policy_linux.cc b/content/common/sandbox_linux/bpf_renderer_policy_linux.cc
index bd252ff755718d5cb28e29252416b5b2c927f835..eabd181fa2af39a95072ecd40d23199b98388215 100644
--- a/content/common/sandbox_linux/bpf_renderer_policy_linux.cc
+++ b/content/common/sandbox_linux/bpf_renderer_policy_linux.cc
@@ -5,22 +5,52 @@
 #include "content/common/sandbox_linux/bpf_renderer_policy_linux.h"
 
 #include <errno.h>
+#include <sys/ioctl.h>
 
 #include "base/basictypes.h"
 #include "build/build_config.h"
 #include "content/common/sandbox_linux/sandbox_linux.h"
 #include "sandbox/linux/bpf_dsl/bpf_dsl.h"
+#include "sandbox/linux/seccomp-bpf-helpers/sigsys_handlers.h"
 #include "sandbox/linux/seccomp-bpf-helpers/syscall_parameters_restrictions.h"
 #include "sandbox/linux/seccomp-bpf-helpers/syscall_sets.h"
 #include "sandbox/linux/system_headers/linux_syscalls.h"
 
+#if defined(USE_VGEM_MAP)
+#include <libdrm/vgem_drm.h>
+#endif
+
 using sandbox::SyscallSets;
 using sandbox::bpf_dsl::Allow;
+using sandbox::bpf_dsl::Arg;
 using sandbox::bpf_dsl::Error;
 using sandbox::bpf_dsl::ResultExpr;
 
 namespace content {
 
+namespace {
+
+ResultExpr RestrictIoctl() {
+#if defined(USE_VGEM_MAP)
+  // The type of DRM_IOCTL_XXX macro is long unsigned int.

[mdempsky, 2015/09/02 22:19:38]

For simplicity, I would suggest writing this as just:

    const Arg<unsigned long> request(1);
    return Switch(request)
        .CASES((static_cast<unsigned long>(TCGETS), FIONREAD), Allow())
#if defined(USE_VGEM_MAP)
        .CASES((DRM_IOCTL_GEM_CLOSE, ...), Allow())
#endif
        .Default(sandbox::CrashSIGSYSIoctl());

There's no need to vary the Arg type parameter based on USE_VGEM_MAP.

(The static_cast is annoying, but unavoidable until we're allowed to use
<initializer_list>. :-/)

[dshwang, 2015/09/03 08:38:04]

Thx for taking your time. Done.

+  auto reference_type = DRM_IOCTL_GEM_CLOSE;
+#else
+  auto reference_type = TCGETS;
+#endif
+  const Arg<decltype(reference_type)> request(1);
+  return Switch(request)
+      .SANDBOX_BPF_DSL_CASES(
+          (static_cast<decltype(reference_type)>(TCGETS), FIONREAD), Allow())
+#if defined(USE_VGEM_MAP)
+      .SANDBOX_BPF_DSL_CASES((DRM_IOCTL_GEM_CLOSE, DRM_IOCTL_VGEM_MODE_MAP_DUMB,
+                              DRM_IOCTL_PRIME_FD_TO_HANDLE),
+                             Allow())
+#endif
+      .Default(sandbox::CrashSIGSYSIoctl());
+}
+
+}  // namespace
+
 RendererProcessPolicy::RendererProcessPolicy() {}
 RendererProcessPolicy::~RendererProcessPolicy() {}
 
@@ -31,7 +61,7 @@ ResultExpr RendererProcessPolicy::EvaluateSyscall(int sysno) const {
     case __NR_clock_getres:
       return sandbox::RestrictClockID();
     case __NR_ioctl:
-      return sandbox::RestrictIoctl();
+      return RestrictIoctl();
     // Allow the system calls below.
     case __NR_fdatasync:
     case __NR_fsync: