1 // Copyright 2014 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 #include "sandbox/linux/seccomp-bpf/bpf_tests.h"
6
7 #include <errno.h>
8 #include <sys/ptrace.h>
9 #include <sys/syscall.h>
10 #include <sys/types.h>
11 #include <unistd.h>
12
13 #include "base/logging.h"
14 #include "base/memory/scoped_ptr.h"
15 #include "build/build_config.h"
16 #include "sandbox/linux/seccomp-bpf/sandbox_bpf.h"
17 #include "sandbox/linux/services/linux_syscalls.h"
18 #include "sandbox/linux/tests/unit_tests.h"
19 #include "testing/gtest/include/gtest/gtest.h"
20
21 namespace sandbox {
22
23 namespace {
24
25 class FourtyTwo {
26 public:
27 static const int kMagicValue = 42;
FourtyTwo()28 FourtyTwo() : value_(kMagicValue) {}
value()29 int value() { return value_; }
30
31 private:
32 int value_;
33 DISALLOW_COPY_AND_ASSIGN(FourtyTwo);
34 };
35
36 class EmptyClassTakingPolicy : public SandboxBPFPolicy {
37 public:
EmptyClassTakingPolicy(FourtyTwo * fourty_two)38 explicit EmptyClassTakingPolicy(FourtyTwo* fourty_two) {
39 BPF_ASSERT(fourty_two);
40 BPF_ASSERT(FourtyTwo::kMagicValue == fourty_two->value());
41 }
~EmptyClassTakingPolicy()42 virtual ~EmptyClassTakingPolicy() {}
43
EvaluateSyscall(SandboxBPF * sandbox,int sysno) const44 virtual ErrorCode EvaluateSyscall(SandboxBPF* sandbox,
45 int sysno) const OVERRIDE {
46 DCHECK(SandboxBPF::IsValidSyscallNumber(sysno));
47 return ErrorCode(ErrorCode::ERR_ALLOWED);
48 }
49 };
50
BPF_TEST(BPFTest,BPFAUXPointsToClass,EmptyClassTakingPolicy,FourtyTwo)51 BPF_TEST(BPFTest,
52 BPFAUXPointsToClass,
53 EmptyClassTakingPolicy,
54 FourtyTwo /* *BPF_AUX */) {
55 // BPF_AUX should point to an instance of FourtyTwo.
56 BPF_ASSERT(BPF_AUX);
57 BPF_ASSERT(FourtyTwo::kMagicValue == BPF_AUX->value());
58 }
59
DummyTestFunction(FourtyTwo * fourty_two)60 void DummyTestFunction(FourtyTwo *fourty_two) {
61 }
62
TEST(BPFTest,BPFTesterCompatibilityDelegateLeakTest)63 TEST(BPFTest, BPFTesterCompatibilityDelegateLeakTest) {
64 // Don't do anything, simply gives dynamic tools an opportunity to detect
65 // leaks.
66 {
67 BPFTesterCompatibilityDelegate<EmptyClassTakingPolicy, FourtyTwo>
68 simple_delegate(DummyTestFunction);
69 }
70 {
71 // Test polymorphism.
72 scoped_ptr<BPFTesterDelegate> simple_delegate(
73 new BPFTesterCompatibilityDelegate<EmptyClassTakingPolicy, FourtyTwo>(
74 DummyTestFunction));
75 }
76 }
77
78 class EnosysPtracePolicy : public SandboxBPFPolicy {
79 public:
EnosysPtracePolicy()80 EnosysPtracePolicy() {
81 my_pid_ = syscall(__NR_getpid);
82 }
~EnosysPtracePolicy()83 virtual ~EnosysPtracePolicy() {
84 // Policies should be able to bind with the process on which they are
85 // created. They should never be created in a parent process.
86 BPF_ASSERT_EQ(my_pid_, syscall(__NR_getpid));
87 }
88
EvaluateSyscall(SandboxBPF * sandbox_compiler,int system_call_number) const89 virtual ErrorCode EvaluateSyscall(SandboxBPF* sandbox_compiler,
90 int system_call_number) const OVERRIDE {
91 if (!SandboxBPF::IsValidSyscallNumber(system_call_number)) {
92 return ErrorCode(ENOSYS);
93 } else if (system_call_number == __NR_ptrace) {
94 // The EvaluateSyscall function should run in the process that created
95 // the current object.
96 BPF_ASSERT_EQ(my_pid_, syscall(__NR_getpid));
97 return ErrorCode(ENOSYS);
98 } else {
99 return ErrorCode(ErrorCode::ERR_ALLOWED);
100 }
101 }
102
103 private:
104 pid_t my_pid_;
105 DISALLOW_COPY_AND_ASSIGN(EnosysPtracePolicy);
106 };
107
108 class BasicBPFTesterDelegate : public BPFTesterDelegate {
109 public:
BasicBPFTesterDelegate()110 BasicBPFTesterDelegate() {}
~BasicBPFTesterDelegate()111 virtual ~BasicBPFTesterDelegate() {}
112
GetSandboxBPFPolicy()113 virtual scoped_ptr<SandboxBPFPolicy> GetSandboxBPFPolicy() OVERRIDE {
114 return scoped_ptr<SandboxBPFPolicy>(new EnosysPtracePolicy());
115 }
RunTestFunction()116 virtual void RunTestFunction() OVERRIDE {
117 errno = 0;
118 int ret = ptrace(PTRACE_TRACEME, -1, NULL, NULL);
119 BPF_ASSERT(-1 == ret);
120 BPF_ASSERT(ENOSYS == errno);
121 }
122
123 private:
124 DISALLOW_COPY_AND_ASSIGN(BasicBPFTesterDelegate);
125 };
126
127 // This is the most powerful and complex way to create a BPF test, but it
128 // requires a full class definition (BasicBPFTesterDelegate).
129 BPF_TEST_D(BPFTest, BPFTestWithDelegateClass, BasicBPFTesterDelegate);
130
131 // This is the simplest form of BPF tests.
BPF_TEST_C(BPFTest,BPFTestWithInlineTest,EnosysPtracePolicy)132 BPF_TEST_C(BPFTest, BPFTestWithInlineTest, EnosysPtracePolicy) {
133 errno = 0;
134 int ret = ptrace(PTRACE_TRACEME, -1, NULL, NULL);
135 BPF_ASSERT(-1 == ret);
136 BPF_ASSERT(ENOSYS == errno);
137 }
138
139 const char kHelloMessage[] = "Hello";
140
BPF_DEATH_TEST_C(BPFTest,BPFDeathTestWithInlineTest,DEATH_MESSAGE (kHelloMessage),EnosysPtracePolicy)141 BPF_DEATH_TEST_C(BPFTest,
142 BPFDeathTestWithInlineTest,
143 DEATH_MESSAGE(kHelloMessage),
144 EnosysPtracePolicy) {
145 LOG(ERROR) << kHelloMessage;
146 _exit(1);
147 }
148
149 } // namespace
150
151 } // namespace sandbox
152