verifier.h revision f2477e01787aa58f445919b809d89e252beef54f 
1// Copyright (c) 2012 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef SANDBOX_LINUX_SECCOMP_BPF_VERIFIER_H__
6#define SANDBOX_LINUX_SECCOMP_BPF_VERIFIER_H__
7
8#include <linux/filter.h>
9
10#include <utility>
11#include <vector>
12
13namespace playground2 {
14
15class SandboxBpfPolicy;
16
17class Verifier {
18 public:
19  // Evaluate the BPF program for all possible inputs and verify that it
20  // computes the correct result. We use the "evaluators" to determine
21  // the full set of possible inputs that we have to iterate over.
22  // Returns success, if the BPF filter accurately reflects the rules
23  // set by the "evaluators".
24  // Upon success, "err" is set to NULL. Upon failure, it contains a static
25  // error message that does not need to be free()'d.
26  static bool VerifyBPF(Sandbox* sandbox,
27                        const std::vector<struct sock_filter>& program,
28                        const SandboxBpfPolicy& policy,
29                        const char** err);
30
31  // Evaluate a given BPF program for a particular set of system call
32  // parameters. If evaluation failed for any reason, "err" will be set to
33  // a non-NULL error string. Otherwise, the BPF program's result will be
34  // returned by the function and "err" is NULL.
35  // We do not actually implement the full BPF state machine, but only the
36  // parts that can actually be generated by our BPF compiler. If this code
37  // is used for purposes other than verifying the output of the sandbox's
38  // BPF compiler, we might have to extend this BPF interpreter.
39  static uint32_t EvaluateBPF(const std::vector<struct sock_filter>& program,
40                              const struct arch_seccomp_data& data,
41                              const char** err);
42
43 private:
44  DISALLOW_IMPLICIT_CONSTRUCTORS(Verifier);
45};
46
47}  // namespace
48
49#endif  // SANDBOX_LINUX_SECCOMP_BPF_VERIFIER_H__
50