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

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

Index: sandbox/linux/seccomp-bpf-helpers/syscall_parameters_restrictions.cc
diff --git a/sandbox/linux/seccomp-bpf-helpers/syscall_parameters_restrictions.cc b/sandbox/linux/seccomp-bpf-helpers/syscall_parameters_restrictions.cc
index 58ffb843a8717c9f659d95db465b0c56a9f3a3b3..7dae38763748051bfbde7f8415ea37865e998dce 100644
--- a/sandbox/linux/seccomp-bpf-helpers/syscall_parameters_restrictions.cc
+++ b/sandbox/linux/seccomp-bpf-helpers/syscall_parameters_restrictions.cc
@@ -35,6 +35,9 @@
 // PNaCl toolchain does not provide sys/ioctl.h header.
 #if !defined(OS_NACL_NONSFI)
 #include <sys/ioctl.h>
+#if defined(USE_VGEM_MAP)
+#include <libdrm/vgem_drm.h>
+#endif
 #endif
 
 #if defined(OS_ANDROID)
@@ -150,9 +153,15 @@ ResultExpr RestrictPrctl() {
 }
 
 ResultExpr RestrictIoctl() {
-  const Arg<int> request(1);
-  return Switch(request).CASES((TCGETS, FIONREAD), Allow()).Default(
-      CrashSIGSYSIoctl());
+  const Arg<unsigned int> request(1);
+  return Switch(request)
+      .CASES((static_cast<unsigned int>(TCGETS), FIONREAD), Allow())

[spang, 2015/08/21 17:28:51]

Why unsigned int rather than unsigned long? The actual parameter type is
"unsigned long".

[mdempsky, 2015/08/21 17:39:47]

Annoying.  POSIX and the Linux man pages say request is an "int", but Linux
<sys/ioctl.h> uses "unsigned long int".

FWIW, the consequence of Arg<32-bit> vs Arg<64-bit> here is whether the compiled
BPF program will include extra checks to reject "impossible" 64-bit arguments
(by crashing).  But since the default case is to crash anyway, there's not much
practical consequence.

[dshwang, 2015/08/21 18:26:33]

Thx for investigation. I rollback this code to ensure both POSIX and Linux.

+#if defined(USE_VGEM_MAP)
+      .CASES((DRM_IOCTL_GEM_CLOSE, DRM_IOCTL_VGEM_MODE_MAP_DUMB,
+              DRM_IOCTL_PRIME_FD_TO_HANDLE),
+             Allow())
+#endif
+      .Default(CrashSIGSYSIoctl());
 }
 
 ResultExpr RestrictMmapFlags() {