Rewrite all BPF policies to use DSL API

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>
 #include <sys/types.h>
 #include <unistd.h>
 
 #include "base/logging.h"
 #include "build/build_config.h"
+#include "sandbox/linux/seccomp-bpf-helpers/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/seccomp-bpf/sandbox_bpf.h"
 #include "sandbox/linux/seccomp-bpf/sandbox_bpf_policy.h"
 #include "sandbox/linux/services/linux_syscalls.h"
 
 // Changing this implementation will have an effect on *all* policies.
 // Currently this means: Renderer/Worker, GPU, Flash and NaCl.
 
+using namespace sandbox::bpf_dsl;
+
 namespace sandbox {
 
 namespace {
 
 bool IsBaselinePolicyAllowed(int sysno) {
   return SyscallSets::IsAllowedAddressSpaceAccess(sysno) ||
          SyscallSets::IsAllowedBasicScheduler(sysno) ||
          SyscallSets::IsAllowedEpoll(sysno) ||
          SyscallSets::IsAllowedFileSystemAccessViaFd(sysno) ||
          SyscallSets::IsAllowedGeneralIo(sysno) ||
@@ skipping 39 matching lines @@
 #if defined(__i386__)
          SyscallSets::IsSocketCall(sysno) ||
 #endif
 #if defined(__arm__)
          SyscallSets::IsArmPciConfig(sysno) ||
 #endif
          SyscallSets::IsTimer(sysno);
 }
 
 // |fs_denied_errno| is the errno return for denied filesystem access.
-ErrorCode EvaluateSyscallImpl(int fs_denied_errno,
-                              pid_t current_pid,
-                              SandboxBPF* sandbox,
-                              int sysno) {
+ResultExpr EvaluateSyscallImpl(int fs_denied_errno,
+                               pid_t current_pid,
+                               int sysno) {
 #if defined(ADDRESS_SANITIZER)
   if (sysno == __NR_sigaltstack) {
     // Required for better stack overflow detection in ASan. Disallowed in
     // non-ASan builds.
-    return ErrorCode(ErrorCode::ERR_ALLOWED);
+    return Allow();
   }
 #endif
   if (IsBaselinePolicyAllowed(sysno)) {
-    return ErrorCode(ErrorCode::ERR_ALLOWED);
+    return Allow();
   }
 
   if (sysno == __NR_clone) {
-    return RestrictCloneToThreadsAndEPERMFork(sandbox);
+    return RestrictCloneToThreadsAndEPERMFork();
   }
 
 #if defined(__x86_64__) || defined(__arm__)
   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);
-    return sandbox->Cond(0, ErrorCode::TP_32BIT, ErrorCode::OP_EQUAL, AF_UNIX,
-                         ErrorCode(ErrorCode::ERR_ALLOWED),
-                         sandbox->Trap(CrashSIGSYS_Handler, NULL));
+    const Arg<int> domain_arg(0);
+    return If(domain_arg == AF_UNIX).Then(
+             Allow()
+           ).Else(
+             bpf_dsl::Trap(CrashSIGSYS_Handler, NULL)
+           );
   }
 #endif
 
   if (sysno == __NR_madvise) {
     // Only allow MADV_DONTNEED (aka MADV_FREE).
-    return sandbox->Cond(2, ErrorCode::TP_32BIT,
-                         ErrorCode::OP_EQUAL, MADV_DONTNEED,
-                         ErrorCode(ErrorCode::ERR_ALLOWED),
-                         ErrorCode(EPERM));
+    const Arg<int> advice_arg(2);
+    return If(advice_arg == MADV_DONTNEED).Then(
+             Allow()
+           ).Else(
+             Error(EPERM)
+           );
   }
 
 #if defined(__i386__) || defined(__x86_64__)
   if (sysno == __NR_mmap)
-    return RestrictMmapFlags(sandbox);
+    return RestrictMmapFlags();
 #endif
 
 #if defined(__i386__) || defined(__arm__)
   if (sysno == __NR_mmap2)
-    return RestrictMmapFlags(sandbox);
+    return RestrictMmapFlags();
 #endif
 
   if (sysno == __NR_mprotect)
-    return RestrictMprotectFlags(sandbox);
+    return RestrictMprotectFlags();
 
   if (sysno == __NR_fcntl)
-    return RestrictFcntlCommands(sandbox);
+    return RestrictFcntlCommands();
 
 #if defined(__i386__) || defined(__arm__)
   if (sysno == __NR_fcntl64)
-    return RestrictFcntlCommands(sandbox);
+    return RestrictFcntlCommands();
 #endif
 
   if (SyscallSets::IsKill(sysno)) {
-    return RestrictKillTarget(current_pid, sandbox, sysno);
+    return RestrictKillTarget(current_pid, sysno);
   }
 
   if (SyscallSets::IsFileSystem(sysno) ||
       SyscallSets::IsCurrentDirectory(sysno)) {
-    return ErrorCode(fs_denied_errno);
+    return Error(fs_denied_errno);
   }
 
   if (SyscallSets::IsAnySystemV(sysno)) {
-    return ErrorCode(EPERM);
+    return Error(EPERM);
   }
 
   if (SyscallSets::IsUmask(sysno) ||
       SyscallSets::IsDeniedFileSystemAccessViaFd(sysno) ||
       SyscallSets::IsDeniedGetOrModifySocket(sysno) ||
       SyscallSets::IsProcessPrivilegeChange(sysno)) {
-    return ErrorCode(EPERM);
+    return Error(EPERM);
   }
 
 #if defined(__i386__)
   if (SyscallSets::IsSocketCall(sysno))
-    return RestrictSocketcallCommand(sandbox);
+    return RestrictSocketcallCommand();
 #endif
 
   if (IsBaselinePolicyWatched(sysno)) {
     // Previously unseen syscalls. TODO(jln): some of these should
     // be denied gracefully right away.
-    return sandbox->Trap(CrashSIGSYS_Handler, NULL);
+    return bpf_dsl::Trap(CrashSIGSYS_Handler, NULL);
   }
 
   // In any other case crash the program with our SIGSYS handler.
-  return sandbox->Trap(CrashSIGSYS_Handler, NULL);
+  return bpf_dsl::Trap(CrashSIGSYS_Handler, NULL);
 }
 
 }  // namespace.
 
 // Unfortunately C++03 doesn't allow delegated constructors.
 // Call other constructor when C++11 lands.
 BaselinePolicy::BaselinePolicy()
     : fs_denied_errno_(EPERM), current_pid_(syscall(__NR_getpid)) {}
 
 BaselinePolicy::BaselinePolicy(int fs_denied_errno)
     : fs_denied_errno_(fs_denied_errno), current_pid_(syscall(__NR_getpid)) {}
 
 BaselinePolicy::~BaselinePolicy() {
   // Make sure that this policy is created, used and destroyed by a single
   // process.
   DCHECK_EQ(syscall(__NR_getpid), current_pid_);
 }
 
-ErrorCode BaselinePolicy::EvaluateSyscall(SandboxBPF* sandbox,
-                                          int sysno) const {
+ResultExpr BaselinePolicy::EvaluateSyscall(int sysno) const {
   // Make sure that this policy is used in the creating process.
   if (1 == sysno) {
     DCHECK_EQ(syscall(__NR_getpid), current_pid_);
   }
-  return EvaluateSyscallImpl(fs_denied_errno_, current_pid_, sandbox, sysno);
+  return EvaluateSyscallImpl(fs_denied_errno_, current_pid_, sysno);
 }
 
 }  // namespace sandbox.