1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
|
/*
* Copyright (C) 2017 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <dlfcn.h>
#include <sys/stat.h>
#include <vector>
#include <gtest/gtest.h>
#include "gtest_globals.h"
#include "utils.h"
#if defined(__BIONIC__)
#include "private/CFIShadow.h"
#endif
// Private libdl interface.
extern "C" {
void __cfi_slowpath(uint64_t CallSiteTypeId, void* Ptr);
void __cfi_slowpath_diag(uint64_t CallSiteTypeId, void* Ptr, void* DiagData);
size_t __cfi_shadow_size();
}
// Disables debuggerd stack traces to speed up death tests, make them less
// noisy in logcat, and avoid expected deaths from showing up in stability
// metrics.
// We don't use the usual libbase class because (a) we don't care about most
// of the signals it blocks but (b) we do need to block SIGILL, which normal
// death tests shouldn't ever hit. (It's possible that a design where a
// deathtest always declares its expected signals up front is a better one,
// and maybe that's an interesting future direction for libbase.)
//
// We include SIGSEGV because there's a test that passes heap addresses to
// __cfi_slowpath and we only map the executable code shadow as readable.
// We don't always get SIGSEGV there though: if the heap allocation happens
// to be close enough to an executable mapping that its shadow is in the
// same page as the executable shadow, we'll get SIGILL/SIGTRAP.
class cfi_test_DeathTest : public testing::Test {
protected:
void SetUp() override {
struct sigaction64 action = {.sa_handler = SIG_DFL};
sigaction64(SIGILL, &action, &previous_sigill_);
sigaction64(SIGSEGV, &action, &previous_sigsegv_);
sigaction64(SIGTRAP, &action, &previous_sigtrap_);
}
void TearDown() override {
sigaction64(SIGTRAP, &previous_sigtrap_, nullptr);
sigaction64(SIGSEGV, &previous_sigsegv_, nullptr);
sigaction64(SIGILL, &previous_sigill_, nullptr);
}
private:
struct sigaction64 previous_sigill_;
struct sigaction64 previous_sigsegv_;
struct sigaction64 previous_sigtrap_;
};
static bool KilledByCfi(int status) {
return WIFSIGNALED(status) &&
(WTERMSIG(status) == SIGTRAP || WTERMSIG(status) == SIGILL || WTERMSIG(status) == SIGSEGV);
}
static void f() {}
static void test_cfi_slowpath_with_alloc() {
std::vector<void*> allocs;
for (size_t i = 0; i < 1000; i++) {
allocs.push_back(malloc(4096));
__cfi_slowpath(46, allocs.back());
}
}
TEST_F(cfi_test_DeathTest, basic) {
#if defined(__BIONIC__)
void* handle;
handle = dlopen("libcfi-test.so", RTLD_NOW | RTLD_LOCAL);
ASSERT_TRUE(handle != nullptr) << dlerror();
EXPECT_NE(0U, __cfi_shadow_size());
#define SYM(type, name) auto name = reinterpret_cast<type>(dlsym(handle, #name))
SYM(size_t (*)(), get_count);
SYM(uint64_t(*)(), get_last_type_id);
SYM(void* (*)(), get_last_address);
SYM(void* (*)(), get_last_diag);
SYM(void* (*)(), get_global_address);
SYM(void (*)(uint64_t, void*, void*), __cfi_check);
SYM(char*, bss);
#undef SYM
size_t c = get_count();
// CFI check for code inside the DSO. Can't use just any function address - this is only
// guaranteed to work for code addresses above __cfi_check.
void* code_ptr = reinterpret_cast<char*>(__cfi_check) + 1234;
void* diag_ptr = reinterpret_cast<void*>(5678);
__cfi_slowpath_diag(42, code_ptr, diag_ptr);
EXPECT_EQ(42U, get_last_type_id());
EXPECT_EQ(code_ptr, get_last_address());
EXPECT_EQ(diag_ptr, get_last_diag());
EXPECT_EQ(++c, get_count());
// __cfi_slowpath passes nullptr for the Diag argument.
__cfi_slowpath(42, code_ptr);
EXPECT_EQ(42U, get_last_type_id());
EXPECT_EQ(code_ptr, get_last_address());
EXPECT_EQ(nullptr, get_last_diag());
EXPECT_EQ(++c, get_count());
// CFI check for a data address inside the DSO.
__cfi_slowpath(43, get_global_address());
EXPECT_EQ(43U, get_last_type_id());
EXPECT_EQ(get_global_address(), get_last_address());
EXPECT_EQ(++c, get_count());
// CFI check for a function inside _this_ DSO. It either goes to this DSO's __cfi_check,
// or (if missing) is simply ignored. Any way, it does not affect the test lib's counters.
__cfi_slowpath(44, reinterpret_cast<void*>(&f));
EXPECT_EQ(43U, get_last_type_id());
EXPECT_EQ(get_global_address(), get_last_address());
EXPECT_EQ(c, get_count());
// CFI check for a heap address.
// It's possible that this allocation could wind up in the same CFI granule as
// an unchecked library, which means the below might not crash. To force a
// crash keep allocating up to a max until there is a crash.
EXPECT_EXIT(test_cfi_slowpath_with_alloc(), KilledByCfi, "");
// Check all the addresses.
const size_t bss_size = 1024 * 1024;
static_assert(bss_size >= kLibraryAlignment * 2, "test range not big enough");
for (size_t i = 0; i < bss_size; ++i) {
__cfi_slowpath(47, bss + i);
EXPECT_EQ(++c, get_count());
}
// Load the same library again.
void* handle2 = dlopen("libcfi-test.so", RTLD_NOW | RTLD_LOCAL);
ASSERT_TRUE(handle2 != nullptr) << dlerror();
EXPECT_EQ(handle2, handle);
// Check that it is still there.
__cfi_slowpath(43, get_global_address());
EXPECT_EQ(43U, get_last_type_id());
EXPECT_EQ(get_global_address(), get_last_address());
EXPECT_EQ(++c, get_count());
dlclose(handle);
dlclose(handle2);
// CFI check for a function inside the unloaded DSO. This is always invalid and gets the process
// killed.
EXPECT_EXIT(__cfi_slowpath(45, reinterpret_cast<void*>(code_ptr)), KilledByCfi, "");
#endif
}
TEST(cfi_test, invalid) {
#if defined(__BIONIC__)
void* handle;
handle = dlopen("libcfi-test-bad.so", RTLD_NOW | RTLD_LOCAL);
ASSERT_FALSE(handle != nullptr) << dlerror();
handle = dlopen("libcfi-test-bad.so", RTLD_NOW | RTLD_LOCAL);
ASSERT_FALSE(handle != nullptr) << dlerror();
#endif
}
// cfi_test_helper exports __cfi_check, which triggers CFI initialization at startup.
TEST(cfi_test, early_init) {
#if defined(__BIONIC__)
std::string helper = GetTestlibRoot() + "/cfi_test_helper";
chmod(helper.c_str(), 0755); // TODO: "x" lost in CTS, b/34945607
ExecTestHelper eth;
eth.SetArgs({ helper.c_str(), nullptr });
eth.Run([&]() { execve(helper.c_str(), eth.GetArgs(), eth.GetEnv()); }, 0, nullptr);
#endif
}
// cfi_test_helper2 depends on a library that exports __cfi_check, which triggers CFI initialization
// at startup.
TEST(cfi_test, early_init2) {
#if defined(__BIONIC__)
std::string helper = GetTestlibRoot() + "/cfi_test_helper2";
chmod(helper.c_str(), 0755); // TODO: "x" lost in CTS, b/34945607
ExecTestHelper eth;
eth.SetArgs({ helper.c_str(), nullptr });
eth.Run([&]() { execve(helper.c_str(), eth.GetArgs(), eth.GetEnv()); }, 0, nullptr);
#endif
}
|
