2 * Copyright (C) 2012 The Android Open Source Project
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
18 * Contributed by: Intel Corporation
21 #include <gtest/gtest.h>
22 #include "BionicDeathTest.h"
30 extern "C" pid_t gettid();
32 // For x86, bionic and glibc have per-thread stack guard values (all identical).
34 static uint32_t GetGuardFromTls() {
36 asm ("mov %%gs:0x14, %0": "=d" (guard));
40 struct stack_protector_checker {
42 std::set<uint32_t> guards;
46 uint32_t guard = GetGuardFromTls();
48 printf("[thread %d] %%gs:0x14 = 0x%08x\n", tid, guard);
50 // Duplicate tid. gettid(2) bug? Seeing this would be very upsetting.
51 ASSERT_TRUE(tids.find(tid) == tids.end());
53 // Uninitialized guard. Our bug. Note this is potentially flaky; we _could_ get
54 // four random zero bytes, but it should be vanishingly unlikely.
62 static void* ThreadGuardHelper(void* arg) {
63 stack_protector_checker* checker = reinterpret_cast<stack_protector_checker*>(arg);
69 TEST(stack_protector, same_guard_per_thread) {
71 stack_protector_checker checker;
72 size_t thread_count = 10;
73 for (size_t i = 0; i < thread_count; ++i) {
75 ASSERT_EQ(0, pthread_create(&t, NULL, ThreadGuardHelper, &checker));
77 ASSERT_EQ(0, pthread_join(t, &result));
78 ASSERT_EQ(NULL, result);
80 ASSERT_EQ(thread_count, checker.tids.size());
82 // bionic and glibc use the same guard for every thread.
83 ASSERT_EQ(1U, checker.guards.size());
85 GTEST_LOG_(INFO) << "This test does nothing.\n";
89 // For ARM and MIPS, glibc has a global stack check guard value.
90 #if defined(__BIONIC__) || defined(__arm__) || defined(__mips__)
91 #define TEST_STACK_CHK_GUARD
93 // Bionic has the global for x86 too, to support binaries that can run on
94 // Android releases that didn't implement the TLS guard value.
95 extern "C" uintptr_t __stack_chk_guard;
98 * When this function returns, the stack canary will be inconsistent
99 * with the previous value, which will generate a call to __stack_chk_fail(),
100 * eventually resulting in a SIGABRT.
102 * This must be marked with "__attribute__ ((noinline))", to ensure the
103 * compiler generates the proper stack guards around this function.
105 static char* dummy_buf;
107 __attribute__ ((noinline))
108 static void do_modify_stack_chk_guard() {
110 // Store local array's address to global variable to force compiler to generate stack guards.
112 __stack_chk_guard = 0x12345678;
117 TEST(stack_protector, global_guard) {
118 #if defined(TEST_STACK_CHK_GUARD)
119 ASSERT_NE(0, gettid());
120 ASSERT_NE(0U, __stack_chk_guard);
121 #else // TEST_STACK_CHK_GUARD
122 GTEST_LOG_(INFO) << "This test does nothing.\n";
123 #endif // TEST_STACK_CHK_GUARD
126 class stack_protector_DeathTest : public BionicDeathTest {};
128 TEST_F(stack_protector_DeathTest, modify_stack_protector) {
129 #if defined(TEST_STACK_CHK_GUARD)
130 ASSERT_EXIT(do_modify_stack_chk_guard(), testing::KilledBySignal(SIGABRT), "");
131 #else // TEST_STACK_CHK_GUARD
132 GTEST_LOG_(INFO) << "This test does nothing.\n";
133 #endif // TEST_STACK_CHK_GUARD