sandbox/linux/seccomp-bpf/bpf_tests.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_BPF_TESTS_H__
   6 #define SANDBOX_LINUX_SECCOMP_BPF_BPF_TESTS_H__
   7
   8 #include <fcntl.h>
   9 #include <sys/stat.h>
  10 #include <sys/types.h>
  11
  12 #include "build/build_config.h"
  13 #include "sandbox/linux/tests/unit_tests.h"
  14 #include "sandbox/linux/seccomp-bpf/sandbox_bpf.h"
  15
  16 namespace sandbox {
  17
  18 // A BPF_DEATH_TEST is just the same as a BPF_TEST, but it assumes that the
  19 // test will fail with a particular known error condition. Use the DEATH_XXX()
  20 // macros from unit_tests.h to specify the expected error condition.
  21 // A BPF_DEATH_TEST is always disabled under ThreadSanitizer, see
  22 // crbug.com/243968.
  23 #define BPF_DEATH_TEST(test_case_name, test_name, death, policy, aux...) \
  24   void BPF_TEST_##test_name(sandbox::BPFTests<aux>::AuxType& BPF_AUX);   \
  25   TEST(test_case_name, DISABLE_ON_TSAN(test_name)) {                     \
  26     sandbox::BPFTests<aux>::TestArgs arg(BPF_TEST_##test_name, policy);  \
  27     sandbox::BPFTests<aux>::RunTestInProcess(                            \
  28         sandbox::BPFTests<aux>::TestWrapper, &arg, death);               \
  29   }                                                                      \
  30   void BPF_TEST_##test_name(sandbox::BPFTests<aux>::AuxType& BPF_AUX)
  31
  32 // BPF_TEST() is a special version of SANDBOX_TEST(). It turns into a no-op,
  33 // if the host does not have kernel support for running BPF filters.
  34 // Also, it takes advantage of the Die class to avoid calling LOG(FATAL), from
  35 // inside our tests, as we don't need or even want all the error handling that
  36 // LOG(FATAL) would do.
  37 // BPF_TEST() takes a C++ data type as an optional fourth parameter. If
  38 // present, this sets up a variable that can be accessed as "BPF_AUX". This
  39 // variable will be passed as an argument to the "policy" function. Policies
  40 // would typically use it as an argument to SandboxBPF::Trap(), if they want to
  41 // communicate data between the BPF_TEST() and a Trap() function.
  42 #define BPF_TEST(test_case_name, test_name, policy, aux...) \
  43   BPF_DEATH_TEST(test_case_name, test_name, DEATH_SUCCESS(), policy, aux)
  44
  45 // Assertions are handled exactly the same as with a normal SANDBOX_TEST()
  46 #define BPF_ASSERT SANDBOX_ASSERT
  47
  48 // The "Aux" type is optional. We use an "empty" type by default, so that if
  49 // the caller doesn't provide any type, all the BPF_AUX related data compiles
  50 // to nothing.
  51 template <class Aux = int[0]>
  52 class BPFTests : public UnitTests {
  53  public:
  54   typedef Aux AuxType;
  55
  56   class TestArgs {
  57    public:
  58     TestArgs(void (*t)(AuxType&), sandbox::SandboxBPF::EvaluateSyscall p)
  59         : test_(t), policy_(p), aux_() {}
  60
  61     void (*test() const)(AuxType&) { return test_; }
  62     sandbox::SandboxBPF::EvaluateSyscall policy() const { return policy_; }
  63
  64    private:
  65     friend class BPFTests;
  66
  67     void (*test_)(AuxType&);
  68     sandbox::SandboxBPF::EvaluateSyscall policy_;
  69     AuxType aux_;
  70   };
  71
  72   static void TestWrapper(void* void_arg) {
  73     TestArgs* arg = reinterpret_cast<TestArgs*>(void_arg);
  74     sandbox::Die::EnableSimpleExit();
  75     if (sandbox::SandboxBPF::SupportsSeccompSandbox(-1) ==
  76         sandbox::SandboxBPF::STATUS_AVAILABLE) {
  77       // Ensure the the sandbox is actually available at this time
  78       int proc_fd;
  79       BPF_ASSERT((proc_fd = open("/proc", O_RDONLY | O_DIRECTORY)) >= 0);
  80       BPF_ASSERT(sandbox::SandboxBPF::SupportsSeccompSandbox(proc_fd) ==
  81                  sandbox::SandboxBPF::STATUS_AVAILABLE);
  82
  83       // Initialize and then start the sandbox with our custom policy
  84       sandbox::SandboxBPF sandbox;
  85       sandbox.set_proc_fd(proc_fd);
  86       sandbox.SetSandboxPolicyDeprecated(arg->policy(), &arg->aux_);
  87       BPF_ASSERT(sandbox.StartSandbox(
  88           sandbox::SandboxBPF::PROCESS_SINGLE_THREADED));
  89
  90       arg->test()(arg->aux_);
  91     } else {
  92       printf("This BPF test is not fully running in this configuration!\n");
  93       // Android and Valgrind are the only configurations where we accept not
  94       // having kernel BPF support.
  95       if (!IsAndroid() && !IsRunningOnValgrind()) {
  96         const bool seccomp_bpf_is_supported = false;
  97         BPF_ASSERT(seccomp_bpf_is_supported);
  98       }
  99       // Call the compiler and verify the policy. That's the least we can do,
 100       // if we don't have kernel support.
 101       sandbox::SandboxBPF sandbox;
 102       sandbox.SetSandboxPolicyDeprecated(arg->policy(), &arg->aux_);
 103       sandbox::SandboxBPF::Program* program =
 104           sandbox.AssembleFilter(true /* force_verification */);
 105       delete program;
 106       sandbox::UnitTests::IgnoreThisTest();
 107     }
 108   }
 109
 110  private:
 111   DISALLOW_IMPLICIT_CONSTRUCTORS(BPFTests);
 112 };
 113
 114 }  // namespace sandbox
 115
 116 #endif  // SANDBOX_LINUX_SECCOMP_BPF_BPF_TESTS_H__