Seccomp-bpf: create system call sets.

We define system call sets to create a partition of all existing system
calls on the x86_64 architecture.

This grand classification will allow us to write policies easily and make
sure that we have thought about what to do for every system call.

This particular change does not affect the current semantic at all, this
is achieved by using comments.

BUG=
NOTRY=true

Review URL: https://chromiumcodereview.appspot.com/10834219

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@150624 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 720 insertions, 96 deletions

diff --git a/content/common/sandbox_seccomp_bpf_linux.cc b/content/common/sandbox_seccomp_bpf_linux.cc
index be331c4..cbea595 100644
--- a/content/common/sandbox_seccomp_bpf_linux.cc
+++ b/content/common/sandbox_seccomp_bpf_linux.cc
@@ -43,18 +43,6 @@ inline bool IsChromeOS() {
 #endif
 }
 
-void LogSandboxStarted(const std::string& sandbox_name,
-                       const std::string& process_type) {
-  const std::string activated_sandbox =
-      "Activated " + sandbox_name + " sandbox for process type: " +
-      process_type + ".";
-  if (IsChromeOS()) {
-    LOG(WARNING) << activated_sandbox;
-  } else {
-    VLOG(1) << activated_sandbox;
-  }
-}
-
 intptr_t CrashSIGSYS_Handler(const struct arch_seccomp_data& args, void* aux) {
   int syscall = args.nr;
   if (syscall >= 1024)
@@ -79,50 +67,6 @@ intptr_t CrashSIGSYS_Handler(const struct arch_seccomp_data& args, void* aux) {
     _exit(1);
 }
 
-// TODO(jln) we need to restrict the first parameter!
-bool IsKillSyscall(int sysno) {
-  switch (sysno) {
-    case __NR_kill:
-    case __NR_tkill:
-    case __NR_tgkill:
-      return true;
-    default:
-      return false;
-  }
-}
-
-bool IsGettimeSyscall(int sysno) {
-  switch (sysno) {
-    case __NR_clock_gettime:
-    case __NR_gettimeofday:
-    case __NR_time:
-      return true;
-    default:
-      return false;
-  }
-}
-
-bool IsFileSystemSyscall(int sysno) {
-  switch (sysno) {
-    case __NR_open:
-    case __NR_openat:
-    case __NR_execve:
-    case __NR_access:
-    case __NR_mkdir:
-    case __NR_mkdirat:
-    case __NR_readlink:
-    case __NR_readlinkat:
-    case __NR_stat:
-    case __NR_lstat:
-    case __NR_chdir:
-    case __NR_mknod:
-    case __NR_mknodat:
-      return true;
-    default:
-      return false;
-  }
-}
-
 bool IsAcceleratedVideoDecodeEnabled() {
   // Accelerated video decode is currently enabled on Chrome OS,
   // but not on Linux: crbug.com/137247.
@@ -204,60 +148,731 @@ intptr_t GpuOpenSIGSYS_Handler(const struct arch_seccomp_data& args,
 }
 
 #if defined(__x86_64__)
-// x86_64 only because it references system calls that are multiplexed on IA32.
-bool IsGpuAndFlashPolicyAllowed_x86_64(int sysno) {
+
+// The functions below cover all existing x86_64 system calls.
+// The implicitly defined sets form a partition of the sets of
+// system calls.
+
+// TODO(jln) we need to restrict the first parameter!
+bool IsKillSyscall(int sysno) {
   switch (sysno) {
-    case __NR_brk:
-    case __NR_clone:  // TODO(jln) restrict flags.
-    case __NR_close:
-    case __NR_dup:
-    case __NR_epoll_create:
-    case __NR_epoll_ctl:
-    case __NR_epoll_wait:
-    case __NR_exit:
-    case __NR_exit_group:
-    case __NR_fcntl:
+    case __NR_kill:
+    case __NR_tkill:
+    case __NR_tgkill:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool IsAllowedGettimeSyscall(int sysno) {
+  switch (sysno) {
+    // case __NR_clock_getres:
+    case __NR_clock_gettime:
+    // case __NR_clock_nanosleep:
+    case __NR_gettimeofday:
+    case __NR_time:
+      return true;
+    case __NR_adjtimex:       // Privileged.
+    case __NR_settimeofday:   // Privileged.
+    case __NR_clock_adjtime:  // Privileged.
+    case __NR_clock_settime:  // Privileged.
+    default:
+      return false;
+  }
+}
+
+bool IsAmbientFileSystemSyscall(int sysno) {
+  switch (sysno)  {
+    // case __NR_getcwd:
+    case __NR_chdir:
+    // case __NR_fchdir:
+    // case __NR_umask:
+      return true;
+    default:
+      return false;
+  }
+}
+
+// System calls that directly access the file system. They might aquire
+// a new file descriptor or otherwise perform an operation directly
+// via a path.
+// For many, EPERM is a valid errno, but not for all of them.
+bool IsFileSystemSyscall(int sysno) {
+  switch (sysno) {
+    case __NR_access:
+    // case __NR_chmod:
+    // case __NR_chown:
+    // case __NR_creat:
+    case __NR_execve:
+    // case __NR_faccessat:
+    // case __NR_fchmodat:
+    // case __NR_fchownat:  // Should be called chownat ?
+    // case __NR_futimesat:  // Should be called utimesat ?
+    // case __NR_getdents:
+    // case __NR_getdents64:
+    // case __NR_lchown:
+    // case __NR_link:
+    // case __NR_linkat:
+    // case __NR_lookup_dcookie:
+    case __NR_lstat:
+    case __NR_mkdir:
+    case __NR_mkdirat:
+    case __NR_mknod:
+    case __NR_mknodat:
+    // case __NR_newfstatat:  // Should be called statat ?
+    case __NR_open:
+    case __NR_openat:
+    case __NR_readlink:
+    case __NR_readlinkat:
+    // case __NR_rename:
+    // case __NR_renameat:
+    // case __NR_rmdir:
+    case __NR_stat:
+    // case __NR_statfs:
+    // case __NR_symlink:
+    // case __NR_symlinkat:
+    // case __NR_truncate:
+    // case __NR_unlink:
+    // case __NR_unlinkat:
+    // case __NR_uselib:
+    // case __NR_ustat:  // Deprecated.
+    // case __NR_utime:
+    // case __NR_utimensat:   // New.
+    // case __NR_utimes:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool IsAllowedFileSystemCapabilitySyscall(int sysno) {
+  switch (sysno) {
+    // case __NR_fadvise64:
+    // case __NR_flock:
     case __NR_fstat:
-    case __NR_futex:
+    // case __NR_fstatfs:  // Give information about the whole filesystem.
+    // case __NR_fsync:
+    // case __NR_fdatasync:
+    // case __NR_sync_file_range:
+      return true;
+    case __NR_fallocate:
+    case __NR_fchmod:
+    case __NR_fchown:
+    case __NR_ftruncate:
+    default:
+      return false;
+  }
+}
+
+bool IsGetProcessIdSyscall(int sysno) {
+  switch (sysno) {
+    // case __NR_capget:
     case __NR_getegid:
     case __NR_geteuid:
     case __NR_getgid:
+    // case __NR_getgroups:
+    // case __NR_getpid:
+    // case __NR_getppid:
+    // case __NR_getresgid:
+    // case __NR_getresuid:
+    // case __NR_getsid:
     case __NR_gettid:
     case __NR_getuid:
-    case __NR_lseek:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool IsProcessPrivilegeChange(int sysno) {
+  switch (sysno) {
+    case __NR_capset:
+    case __NR_ioperm:  // Intel privilege.
+    case __NR_iopl:    // Intel privilege.
+    case __NR_setfsgid:
+    case __NR_setfsuid:
+    case __NR_setgid:
+    case __NR_setgroups:
+    case __NR_setregid:
+    case __NR_setresgid:
+    case __NR_setresuid:
+    case __NR_setreuid:
+    case __NR_setuid:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool IsProcessGroupOrSession(int sysno) {
+  switch (sysno) {
+    case __NR_setpgid:
+    case __NR_getpgrp:
+    case __NR_setsid:
+    case __NR_getpgid:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool IsAllowedSignalHandling(int sysno) {
+  switch (sysno) {
+    case __NR_rt_sigaction:
+    // case __NR_rt_sigpending:
+    case __NR_rt_sigprocmask:
+    // case __NR_rt_sigqueueinfo:
+    case __NR_rt_sigreturn:
+    // case __NR_rt_sigsuspend:
+    // case __NR_rt_sigtimedwait:
+    // case __NR_rt_tgsigqueueinfo:
+    // case __NR_sigaltstack:
+    // case __NR_signalfd:
+    // case __NR_signalfd4:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool IsOperationOnFd(int sysno) {
+  switch (sysno) {
+    case __NR_close:
+    case __NR_dup:
+    // case __NR_dup2:
+    // case __NR_dup3:
+    case __NR_fcntl:
+    case __NR_shutdown:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool IsKernelInteralApi(int sysno) {
+  switch (sysno) {
+    case __NR_restart_syscall:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool IsAllowedProcessStartOrDeath(int sysno) {
+  switch (sysno) {
+    case __NR_clone:  // TODO(jln): restrict flags.
+    case __NR_exit:
+    case __NR_exit_group:
+    // case __NR_fork:
+    // case __NR_get_thread_area:
+    // case __NR_set_thread_area:
+    // case __NR_set_tid_address:
+    // case __NR_unshare:
+    // case __NR_vfork:
+    // case __NR_wait4:
+    // case __NR_waitid:
+      return true;
+    case __NR_setns:  // Privileged.
+    default:
+      return false;
+  }
+}
+
+bool IsAllowedEpoll(int sysno) {
+  switch (sysno) {
+    case __NR_epoll_create:
+    // case __NR_epoll_create1:
+    case __NR_epoll_ctl:
+    // case __NR_epoll_ctl_old:
+    // case __NR_epoll_pwait:
+    case __NR_epoll_wait:
+    // case __NR_epoll_wait_old:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool IsAllowedGetOrModifySocket(int sysno) {
+  switch (sysno) {
+    case __NR_pipe:
+    // case __NR_pipe2:
+    case __NR_socketpair:  // We will want to inspect its argument.
+      return true;
+    default:
+    case __NR_accept:
+    case __NR_accept4:
+    case __NR_bind:
+    case __NR_connect:
+    case __NR_socket:
+    case __NR_listen:
+      return false;
+  }
+}
+
+bool IsNetworkSocketInformation(int sysno) {
+  switch (sysno) {
+    case __NR_getpeername:
+    case __NR_getsockname:
+    case __NR_getsockopt:
+    case __NR_setsockopt:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool IsFutex(int sysno) {
+  switch (sysno) {
+    case __NR_futex:
+    // case __NR_get_robust_list:
+    case __NR_set_robust_list:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool IsAllowedAddressSpaceAccess(int sysno) {
+  switch (sysno) {
+    case __NR_brk:
     case __NR_madvise:
+    // case __NR_mincore:
+    // case __NR_mlock:
+    // case __NR_mlockall:
     case __NR_mmap:
+    // case __NR_modify_ldt:
     case __NR_mprotect:
+    // case __NR_mremap:
+    // case __NR_msync:
+    // case __NR_munlock:
+    // case __NR_munlockall:
     case __NR_munmap:
-    case __NR_pipe:
-    case __NR_prctl:
+    // case __NR_readahead:
+    // case __NR_remap_file_pages:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool IsAllowedGeneralIo(int sysno) {
+  switch (sysno) {
+    case __NR_lseek:
+    // case __NR_poll:
+    // case __NR_ppoll:
+    // case __NR_pread64:
+    // case __NR_preadv:
+    // case __NR_pselect6:
+    // case __NR_pwrite64:
+    // case __NR_pwritev:
     case __NR_read:
-    case __NR_recvmsg:
-    case __NR_restart_syscall:
-    case __NR_rt_sigaction:  // Breakpad signal handler.
-    case __NR_rt_sigprocmask:
-    case __NR_rt_sigreturn:
-    case __NR_sched_yield:
-    case __NR_sendmsg:
-    case __NR_set_robust_list:
-    case __NR_shutdown:
-    case __NR_socketpair:
+    // case __NR_readv:
+    // case __NR_recvfrom:  // Could specify source.
+    // case __NR_recvmmsg:  // Could specify source.
+    case __NR_recvmsg:   // Could specify source.
+    // case __NR_select:
+    // case __NR_sendfile:
+    // case __NR_sendmmsg:  // Could specify destination.
+    case __NR_sendmsg:   // Could specify destination.
+    // case __NR_sendto:    // Could specify destination.
+    // case __NR_splice:
+    // case __NR_tee:
+    // case __NR_vmsplice:
     case __NR_write:
+    // case __NR_writev:
       return true;
     default:
-      if (IsGettimeSyscall(sysno) ||
-          IsKillSyscall(sysno)) {
-        return true;
-      } else {
-        return false;
-      }
+    case __NR_ioctl:  // Can be very powerful.
+      return false;
+  }
+}
+
+bool IsAllowedPrctl(int sysno) {
+  switch (sysno) {
+    case __NR_prctl:
+    // case __NR_arch_prctl:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool IsAllowedBasicScheduler(int sysno) {
+  switch (sysno) {
+    case __NR_sched_yield:
+    // case __NR_pause:
+    // case __NR_nanosleep:
+    // case __NR_getpriority:
+      return true;
+    case __NR_setpriority:
+    default:
+      return false;
+  }
+}
+
+bool IsAdminOperation(int sysno) {
+  switch (sysno) {
+    case __NR_kexec_load:
+    case __NR_reboot:
+    case __NR_setdomainname:
+    case __NR_sethostname:
+    case __NR_syslog:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool IsKernelModule(int sysno) {
+  switch (sysno) {
+    case __NR_create_module:
+    case __NR_delete_module:
+    case __NR_get_kernel_syms:  // Should ENOSYS.
+    case __NR_init_module:
+    case __NR_query_module:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool IsGlobalFSViewChange(int sysno) {
+  switch (sysno) {
+    case __NR_pivot_root:
+    case __NR_chroot:
+    case __NR_sync:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool IsFsControl(int sysno) {
+  switch (sysno) {
+    case __NR_mount:
+    case __NR_nfsservctl:
+    case __NR_quotactl:
+    case __NR_swapoff:
+    case __NR_swapon:
+    case __NR_umount2:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool IsNuma(int sysno) {
+  switch (sysno) {
+    case __NR_get_mempolicy:
+    case __NR_getcpu:
+    case __NR_mbind:
+    case __NR_migrate_pages:
+    case __NR_move_pages:
+    case __NR_set_mempolicy:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool IsMessageQueue(int sysno) {
+  switch (sysno) {
+    case __NR_mq_getsetattr:
+    case __NR_mq_notify:
+    case __NR_mq_open:
+    case __NR_mq_timedreceive:
+    case __NR_mq_timedsend:
+    case __NR_mq_unlink:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool IsGlobalProcessEnvironment(int sysno) {
+  switch (sysno) {
+    case __NR_acct:         // Privileged.
+    case __NR_getrlimit:
+    case __NR_getrusage:
+    case __NR_personality:  // Can change its personality as well.
+    case __NR_prlimit64:    // Like setrlimit / getrlimit.
+    case __NR_setrlimit:
+    case __NR_times:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool IsDebug(int sysno) {
+  switch (sysno) {
+    case __NR_ptrace:
+    case __NR_process_vm_readv:
+    case __NR_process_vm_writev:
+    case __NR_kcmp:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool IsGlobalSystemStatus(int sysno) {
+  switch (sysno) {
+    case __NR__sysctl:
+    case __NR_sysfs:
+    case __NR_sysinfo:
+    case __NR_uname:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool IsEventFd(int sysno) {
+  switch (sysno) {
+    case __NR_eventfd:
+    // case __NR_eventfd2:
+      return true;
+    default:
+      return false;
+  }
+}
+
+// Asynchronous I/O API.
+bool IsAsyncIo(int sysno) {
+  switch (sysno) {
+    case __NR_io_cancel:
+    case __NR_io_destroy:
+    case __NR_io_getevents:
+    case __NR_io_setup:
+    case __NR_io_submit:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool IsKeyManagement(int sysno) {
+  switch (sysno) {
+    case __NR_add_key:
+    case __NR_keyctl:
+    case __NR_request_key:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool IsSystemVSemaphores(int sysno) {
+  switch (sysno) {
+    case __NR_semctl:
+    case __NR_semget:
+    case __NR_semop:
+    case __NR_semtimedop:
+      return true;
+    default:
+      return false;
+  }
+}
+
+// These give a lot of ambient authority and bypass the setuid sandbox.
+bool IsSystemVSharedMemory(int sysno) {
+  switch (sysno) {
+    case __NR_shmat:
+    case __NR_shmctl:
+    case __NR_shmdt:
+    // case __NR_shmget:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool IsSystemVMessageQueue(int sysno) {
+  switch (sysno) {
+    case __NR_msgctl:
+    case __NR_msgget:
+    case __NR_msgrcv:
+    case __NR_msgsnd:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool IsAdvancedScheduler(int sysno) {
+  switch (sysno) {
+    case __NR_ioprio_get:  // IO scheduler.
+    case __NR_ioprio_set:
+    case __NR_sched_get_priority_max:
+    case __NR_sched_get_priority_min:
+    case __NR_sched_getaffinity:
+    case __NR_sched_getparam:
+    case __NR_sched_getscheduler:
+    case __NR_sched_rr_get_interval:
+    case __NR_sched_setaffinity:
+    case __NR_sched_setparam:
+    case __NR_sched_setscheduler:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool IsInotify(int sysno) {
+  switch (sysno) {
+    case __NR_inotify_add_watch:
+    case __NR_inotify_init:
+    case __NR_inotify_init1:
+    case __NR_inotify_rm_watch:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool IsFaNotify(int sysno) {
+  switch (sysno) {
+    case __NR_fanotify_init:
+    case __NR_fanotify_mark:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool IsTimer(int sysno) {
+  switch (sysno) {
+    case __NR_getitimer:
+    case __NR_alarm:
+    case __NR_setitimer:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool IsAdvancedTimer(int sysno) {
+  switch (sysno) {
+    case __NR_timer_create:
+    case __NR_timer_delete:
+    case __NR_timer_getoverrun:
+    case __NR_timer_gettime:
+    case __NR_timer_settime:
+    case __NR_timerfd_create:
+    case __NR_timerfd_gettime:
+    case __NR_timerfd_settime:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool IsExtendedAttributes(int sysno) {
+  switch (sysno) {
+    case __NR_fgetxattr:
+    case __NR_flistxattr:
+    case __NR_fremovexattr:
+    case __NR_fsetxattr:
+    case __NR_getxattr:
+    case __NR_lgetxattr:
+    case __NR_listxattr:
+    case __NR_llistxattr:
+    case __NR_lremovexattr:
+    case __NR_lsetxattr:
+    case __NR_removexattr:
+    case __NR_setxattr:
+      return true;
+    default:
+      return false;
+  }
+}
+
+// Various system calls that need to be researched.
+// TODO(jln): classify this better.
+bool IsMiscSyscall(int sysno) {
+  switch (sysno) {
+    case __NR_name_to_handle_at:
+    case __NR_open_by_handle_at:
+    case __NR_perf_event_open:
+    case __NR_syncfs:
+    case __NR_vhangup:
+    // The system calls below are not implemented.
+    case __NR_afs_syscall:
+    case __NR_getpmsg:
+    case __NR_putpmsg:
+    case __NR_security:
+    case __NR_tuxcall:
+    case __NR_vserver:
+      return true;
+    default:
+      return false;
+  }
+}
+
+// End of the system call sets section.
+
+// x86_64 only because it references system calls that are multiplexed on IA32.
+bool IsGpuAndFlashPolicyAllowed_x86_64(int sysno) {
+  if (IsAllowedAddressSpaceAccess(sysno) ||
+      IsAllowedBasicScheduler(sysno) ||
+      IsAllowedEpoll(sysno) ||
+      IsAllowedFileSystemCapabilitySyscall(sysno) ||
+      IsAllowedGeneralIo(sysno) ||
+      IsAllowedGetOrModifySocket(sysno) ||
+      IsAllowedGettimeSyscall(sysno) ||
+      IsAllowedPrctl(sysno) ||
+      IsAllowedProcessStartOrDeath(sysno) ||
+      IsAllowedSignalHandling(sysno) ||
+      IsFutex(sysno) ||
+      IsGetProcessIdSyscall(sysno) ||
+      IsKernelInteralApi(sysno) ||
+      IsKillSyscall(sysno) ||
+      IsOperationOnFd(sysno)) {
+    return true;
+  } else {
+    return false;
+  }
+}
+
+// System calls that will trigger the crashing sigsys handler.
+bool IsGpuAndFlashPolicyWatched_x86_64(int sysno) {
+  if (IsAdminOperation(sysno) ||
+      IsAdvancedScheduler(sysno) ||
+      IsAdvancedTimer(sysno) ||
+      IsAsyncIo(sysno) ||
+      IsDebug(sysno) ||
+      IsEventFd(sysno) ||
+      IsExtendedAttributes(sysno) ||
+      IsFaNotify(sysno) ||
+      IsFsControl(sysno) ||
+      IsGlobalFSViewChange(sysno) ||
+      IsGlobalProcessEnvironment(sysno) ||
+      IsGlobalSystemStatus(sysno) ||
+      IsInotify(sysno) ||
+      IsKernelModule(sysno) ||
+      IsKeyManagement(sysno) ||
+      IsMessageQueue(sysno) ||
+      IsMiscSyscall(sysno) ||
+      IsNetworkSocketInformation(sysno) ||
+      IsNuma(sysno) ||
+      IsProcessGroupOrSession(sysno) ||
+      IsProcessPrivilegeChange(sysno) ||
+      IsSystemVMessageQueue(sysno) ||
+      IsSystemVSemaphores(sysno) ||
+      IsSystemVSharedMemory(sysno) ||
+      IsTimer(sysno)) {
+    return true;
+  } else {
+    return false;
   }
 }
 
 // x86_64 only because it references system calls that are multiplexed on IA32.
 playground2::Sandbox::ErrorCode GpuProcessPolicy_x86_64(int sysno) {
   switch(sysno) {
-    case __NR_eventfd2:
     case __NR_getpid:  // Nvidia binary driver.
     case __NR_getppid:  // ATI binary driver.
     case __NR_ioctl:
@@ -287,14 +902,20 @@ playground2::Sandbox::ErrorCode GpuProcessPolicy_x86_64(int sysno) {
         return playground2::Sandbox::ErrorCode(GpuOpenSIGSYS_Handler, NULL);
       }
     default:
-      if (IsGpuAndFlashPolicyAllowed_x86_64(sysno)) {
+      if (IsGpuAndFlashPolicyAllowed_x86_64(sysno) || IsEventFd(sysno)) {
         return playground2::Sandbox::SB_ALLOWED;
       }
       // Generally, filename-based syscalls will fail with ENOENT to behave
       // similarly to a possible future setuid sandbox.
-      if (IsFileSystemSyscall(sysno)) {
+      if (IsFileSystemSyscall(sysno) || IsAmbientFileSystemSyscall(sysno)) {
         return ENOENT;
       }
+
+      if (IsGpuAndFlashPolicyWatched_x86_64(sysno)) {
+          // Previously unseen syscalls. TODO(jln): some of these should
+          // be denied gracefully right away.
+          return playground2::Sandbox::ErrorCode(CrashSIGSYS_Handler, NULL);
+      }
       // In any other case crash the program with our SIGSYS handler
       return playground2::Sandbox::ErrorCode(CrashSIGSYS_Handler, NULL);
   }
@@ -306,9 +927,6 @@ playground2::Sandbox::ErrorCode FlashProcessPolicy_x86_64(int sysno) {
     case __NR_sched_getaffinity:
     case __NR_sched_setscheduler:
     // These are under investigation, and hopefully not here for the long term.
-    case __NR_shmat:
-    case __NR_shmctl:
-    case __NR_shmdt:
     case __NR_times:
     case __NR_wait4:
       return playground2::Sandbox::SB_ALLOWED;
@@ -317,12 +935,18 @@ playground2::Sandbox::ErrorCode FlashProcessPolicy_x86_64(int sysno) {
     case __NR_socket:
       return EACCES;
     default:
-      if (IsGpuAndFlashPolicyAllowed_x86_64(sysno)) {
+      if (IsGpuAndFlashPolicyAllowed_x86_64(sysno) ||
+          IsSystemVSharedMemory(sysno)) {
         return playground2::Sandbox::SB_ALLOWED;
       }
-      if (IsFileSystemSyscall(sysno)) {
+      if (IsFileSystemSyscall(sysno) || IsAmbientFileSystemSyscall(sysno)) {
         return ENOENT;
       }
+      if (IsGpuAndFlashPolicyWatched_x86_64(sysno)) {
+          // Previously unseen syscalls. TODO(jln): some of these should
+          // be denied gracefully right away.
+          return playground2::Sandbox::ErrorCode(CrashSIGSYS_Handler, NULL);
+      }
       // In any other case crash the program with our SIGSYS handler.
       return playground2::Sandbox::ErrorCode(CrashSIGSYS_Handler, NULL);
   }