sandbox: Add Arm64 support for seccomp-BPF

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

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "sandbox/linux/seccomp-bpf-helpers/baseline_policy.h"
 
 #include <errno.h>
 #include <sys/mman.h>
 #include <sys/socket.h>
 #include <sys/syscall.h>
@@ skipping 102 matching lines @@
     // non-ASan builds.
     return Allow();
   }
 #endif  // defined(ADDRESS_SANITIZER) || defined(THREAD_SANITIZER) ||
         // defined(MEMORY_SANITIZER)
 
   if (IsBaselinePolicyAllowed(sysno)) {
     return Allow();
   }
 
+#if defined(__aarch64__)
+  // These are needed for thread creation.
+  // TODO(leecam): Check jln's fix for this and remove these 'allows'.
+  if (sysno == __NR_sigaltstack || sysno == __NR_setpriority)
+    return Allow();
+#endif
+
   if (sysno == __NR_clone) {
     return RestrictCloneToThreadsAndEPERMFork();
   }
 
   if (sysno == __NR_fcntl)
     return RestrictFcntlCommands();
 
 #if defined(__i386__) || defined(__arm__) || defined(__mips__)
   if (sysno == __NR_fcntl64)
     return RestrictFcntlCommands();
 #endif
 
+#if !defined(__aarch64__)
   // fork() is never used as a system call (clone() is used instead), but we
   // have seen it in fallback code on Android.
   if (sysno == __NR_fork) {
     return Error(EPERM);
   }
+#endif
 
   if (sysno == __NR_futex)
     return RestrictFutex();
 
   if (sysno == __NR_madvise) {
     // Only allow MADV_DONTNEED (aka MADV_FREE).
     const Arg<int> advice(2);
     return If(advice == MADV_DONTNEED, Allow()).Else(Error(EPERM));
   }
 
-#if defined(__i386__) || defined(__x86_64__) || defined(__mips__)
+#if defined(__i386__) || defined(__x86_64__) || defined(__mips__) || \
+    defined(__aarch64__)
   if (sysno == __NR_mmap)
     return RestrictMmapFlags();
 #endif
 
 #if defined(__i386__) || defined(__arm__) || defined(__mips__)
   if (sysno == __NR_mmap2)
     return RestrictMmapFlags();
 #endif
 
   if (sysno == __NR_mprotect)
     return RestrictMprotectFlags();
 
   if (sysno == __NR_prctl)
     return sandbox::RestrictPrctl();
 
-#if defined(__x86_64__) || defined(__arm__) || defined(__mips__)
+#if defined(__x86_64__) || defined(__arm__) || defined(__mips__) || \
+    defined(__aarch64__)
   if (sysno == __NR_socketpair) {
     // Only allow AF_UNIX, PF_UNIX. Crash if anything else is seen.
     COMPILE_ASSERT(AF_UNIX == PF_UNIX, af_unix_pf_unix_different);
     const Arg<int> domain(0);
     return If(domain == AF_UNIX, Allow()).Else(CrashSIGSYS());
   }
 #endif
 
   if (SyscallSets::IsKill(sysno)) {
     return RestrictKillTarget(current_pid, sysno);
@@ skipping 57 matching lines @@
     DCHECK_EQ(syscall(__NR_getpid), current_pid_);
   }
   return EvaluateSyscallImpl(fs_denied_errno_, current_pid_, sysno);
 }
 
 ResultExpr BaselinePolicy::InvalidSyscall() const {
   return CrashSIGSYS();
 }
 
 }  // namespace sandbox.