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 <linux/filter.h>
   9
  10 #include <utility>
  11 #include <vector>
  12
  13 namespace sandbox {
  14
  15 class SandboxBPFPolicy;
  16
  17 class 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(SandboxBPF* 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 sandbox
  48
  49 #endif  // SANDBOX_LINUX_SECCOMP_BPF_VERIFIER_H__