Added a new Verifier class to the BPF compiler.

sandbox/linux/seccomp-bpf/sandbox_bpf.cc

Index: sandbox/linux/seccomp-bpf/sandbox_bpf.cc
diff --git a/sandbox/linux/seccomp-bpf/sandbox_bpf.cc b/sandbox/linux/seccomp-bpf/sandbox_bpf.cc
index e7b1da65299c7557cc28e893c9f9e19cf6f2171d..8fbd3f27058885bf15a06bbc4bcda94eab95e03e 100644
--- a/sandbox/linux/seccomp-bpf/sandbox_bpf.cc
+++ b/sandbox/linux/seccomp-bpf/sandbox_bpf.cc
@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 #include "sandbox/linux/seccomp-bpf/sandbox_bpf.h"
+#include "sandbox/linux/seccomp-bpf/verifier.h"
 
 // The kernel gives us a sandbox, we turn it into a playground :-)
 // This is version 2 of the playground; version 1 was built on top of
@@ -269,6 +270,10 @@ void Sandbox::installFilter() {
   program.push_back((struct sock_filter)
     BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_ERRNO + SECCOMP_DENY_ERRNO));
 
+  // Make sure compilation resulted in BPF program that executes
+  // correctly.
+  Verifier::verifyBPF(program, evaluators_);
+
   // Install BPF filter program
   const struct sock_fprog prog = { program.size(), &program[0] };
   if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0) ||
@@ -313,7 +318,6 @@ void Sandbox::sigSys(int nr, siginfo_t *info, void *void_context) {
 bool Sandbox::suppressLogging_          = false;
 Sandbox::SandboxStatus Sandbox::status_ = STATUS_UNKNOWN;
 int    Sandbox::proc_fd_                = -1;
-std::vector<std::pair<Sandbox::EvaluateSyscall,
-                      Sandbox::EvaluateArguments> > Sandbox::evaluators_;
+Sandbox::Evaluators Sandbox::evaluators_;
 
 }  // namespace