sandbox/linux/seccomp-bpf/verifier.h

   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 <stdint.h>
   9
  10 #include <vector>
  11
  12 #include "base/macros.h"
  13
  14 struct sock_filter;
  15
  16 namespace sandbox {
  17 struct arch_seccomp_data;
  18 namespace bpf_dsl {
  19 class Policy;
  20 class PolicyCompiler;
  21 }
  22
  23 class Verifier {
  24  public:
  25   // Evaluate the BPF program for all possible inputs and verify that it
  26   // computes the correct result. We use the "evaluators" to determine
  27   // the full set of possible inputs that we have to iterate over.
  28   // Returns success, if the BPF filter accurately reflects the rules
  29   // set by the "evaluators".
  30   // Upon success, "err" is set to NULL. Upon failure, it contains a static
  31   // error message that does not need to be free()'d.
  32   static bool VerifyBPF(bpf_dsl::PolicyCompiler* compiler,
  33                         const std::vector<struct sock_filter>& program,
  34                         const bpf_dsl::Policy& policy,
  35                         const char** err);
  36
  37   // Evaluate a given BPF program for a particular set of system call
  38   // parameters. If evaluation failed for any reason, "err" will be set to
  39   // a non-NULL error string. Otherwise, the BPF program's result will be
  40   // returned by the function and "err" is NULL.
  41   // We do not actually implement the full BPF state machine, but only the
  42   // parts that can actually be generated by our BPF compiler. If this code
  43   // is used for purposes other than verifying the output of the sandbox's
  44   // BPF compiler, we might have to extend this BPF interpreter.
  45   static uint32_t EvaluateBPF(const std::vector<struct sock_filter>& program,
  46                               const struct arch_seccomp_data& data,
  47                               const char** err);
  48
  49  private:
  50   DISALLOW_IMPLICIT_CONSTRUCTORS(Verifier);
  51 };
  52
  53 }  // namespace sandbox
  54
  55 #endif  // SANDBOX_LINUX_SECCOMP_BPF_VERIFIER_H__