Elliott Hughes | ad88a08 | 2012-10-24 18:37:21 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2012 The Android Open Source Project |
| 3 | * |
| 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 |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 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. |
| 15 | */ |
| 16 | |
| 17 | /* |
| 18 | * Contributed by: Intel Corporation |
| 19 | */ |
| 20 | |
| 21 | #include <gtest/gtest.h> |
| 22 | |
| 23 | #include <pthread.h> |
| 24 | #include <stdint.h> |
| 25 | #include <stdio.h> |
| 26 | #include <sys/syscall.h> |
| 27 | #include <unistd.h> |
| 28 | #include <set> |
| 29 | |
| 30 | #ifdef __GLIBC__ |
| 31 | |
| 32 | // glibc doesn't expose gettid(2). |
| 33 | pid_t gettid() { return syscall(__NR_gettid); } |
| 34 | |
| 35 | #endif |
| 36 | |
| 37 | #ifdef __i386__ |
| 38 | |
Elliott Hughes | fb7eb5e | 2013-02-14 14:37:34 -0800 | [diff] [blame] | 39 | // For x86, bionic and glibc have per-thread stack guard values (all identical). |
Elliott Hughes | ad88a08 | 2012-10-24 18:37:21 -0700 | [diff] [blame] | 40 | |
| 41 | static uint32_t GetGuardFromTls() { |
| 42 | uint32_t guard; |
| 43 | asm ("mov %%gs:0x14, %0": "=d" (guard)); |
| 44 | return guard; |
| 45 | } |
| 46 | |
| 47 | struct stack_protector_checker { |
| 48 | std::set<pid_t> tids; |
| 49 | std::set<uint32_t> guards; |
| 50 | |
| 51 | void Check() { |
| 52 | pid_t tid = gettid(); |
| 53 | uint32_t guard = GetGuardFromTls(); |
| 54 | |
| 55 | printf("[thread %d] %%gs:0x14 = 0x%08x\n", tid, guard); |
| 56 | |
| 57 | // Duplicate tid. gettid(2) bug? Seeing this would be very upsetting. |
| 58 | ASSERT_TRUE(tids.find(tid) == tids.end()); |
Elliott Hughes | d3920b3 | 2013-02-07 18:39:34 -0800 | [diff] [blame] | 59 | |
Elliott Hughes | ad88a08 | 2012-10-24 18:37:21 -0700 | [diff] [blame] | 60 | // Uninitialized guard. Our bug. Note this is potentially flaky; we _could_ get |
| 61 | // four random zero bytes, but it should be vanishingly unlikely. |
| 62 | ASSERT_NE(guard, 0U); |
| 63 | |
| 64 | tids.insert(tid); |
| 65 | guards.insert(guard); |
| 66 | } |
| 67 | }; |
| 68 | |
| 69 | static void* ThreadGuardHelper(void* arg) { |
| 70 | stack_protector_checker* checker = reinterpret_cast<stack_protector_checker*>(arg); |
| 71 | checker->Check(); |
| 72 | return NULL; |
| 73 | } |
| 74 | |
Elliott Hughes | d3920b3 | 2013-02-07 18:39:34 -0800 | [diff] [blame] | 75 | TEST(stack_protector, same_guard_per_thread) { |
Elliott Hughes | ad88a08 | 2012-10-24 18:37:21 -0700 | [diff] [blame] | 76 | stack_protector_checker checker; |
| 77 | size_t thread_count = 10; |
| 78 | for (size_t i = 0; i < thread_count; ++i) { |
| 79 | pthread_t t; |
| 80 | ASSERT_EQ(0, pthread_create(&t, NULL, ThreadGuardHelper, &checker)); |
| 81 | void* result; |
| 82 | ASSERT_EQ(0, pthread_join(t, &result)); |
| 83 | ASSERT_EQ(NULL, result); |
| 84 | } |
| 85 | ASSERT_EQ(thread_count, checker.tids.size()); |
| 86 | |
Elliott Hughes | d3920b3 | 2013-02-07 18:39:34 -0800 | [diff] [blame] | 87 | // bionic and glibc use the same guard for every thread. |
Elliott Hughes | ad88a08 | 2012-10-24 18:37:21 -0700 | [diff] [blame] | 88 | ASSERT_EQ(1U, checker.guards.size()); |
Elliott Hughes | ad88a08 | 2012-10-24 18:37:21 -0700 | [diff] [blame] | 89 | } |
| 90 | |
| 91 | #endif |
| 92 | |
| 93 | #if defined(__BIONIC__) || defined(__arm__) || defined(__mips__) |
| 94 | |
| 95 | // For ARM and MIPS, glibc has a global stack check guard value. |
| 96 | |
| 97 | // Bionic has the global for x86 too, to support binaries that can run on |
| 98 | // Android releases that didn't implement the TLS guard value. |
| 99 | |
Elliott Hughes | d3920b3 | 2013-02-07 18:39:34 -0800 | [diff] [blame] | 100 | extern "C" uintptr_t __stack_chk_guard; |
Elliott Hughes | ad88a08 | 2012-10-24 18:37:21 -0700 | [diff] [blame] | 101 | |
| 102 | TEST(stack_protector, global_guard) { |
| 103 | ASSERT_NE(0, gettid()); |
Elliott Hughes | d3920b3 | 2013-02-07 18:39:34 -0800 | [diff] [blame] | 104 | ASSERT_NE(0U, __stack_chk_guard); |
Elliott Hughes | ad88a08 | 2012-10-24 18:37:21 -0700 | [diff] [blame] | 105 | } |
| 106 | |
Nick Kralevich | dcab1b2 | 2013-01-10 17:12:29 -0800 | [diff] [blame] | 107 | /* |
| 108 | * When this function returns, the stack canary will be inconsistent |
| 109 | * with the previous value, which will generate a call to __stack_chk_fail(), |
| 110 | * eventually resulting in a SIGABRT. |
| 111 | * |
| 112 | * This must be marked with "__attribute__ ((noinline))", to ensure the |
| 113 | * compiler generates the proper stack guards around this function. |
| 114 | */ |
| 115 | __attribute__ ((noinline)) |
| 116 | static void do_modify_stack_chk_guard() { |
Elliott Hughes | d3920b3 | 2013-02-07 18:39:34 -0800 | [diff] [blame] | 117 | __stack_chk_guard = 0x12345678; |
Nick Kralevich | dcab1b2 | 2013-01-10 17:12:29 -0800 | [diff] [blame] | 118 | } |
| 119 | |
Nick Kralevich | dcab1b2 | 2013-01-10 17:12:29 -0800 | [diff] [blame] | 120 | TEST(stack_protector_DeathTest, modify_stack_protector) { |
| 121 | ::testing::FLAGS_gtest_death_test_style = "threadsafe"; |
Elliott Hughes | 7fd803c | 2013-02-14 16:33:52 -0800 | [diff] [blame] | 122 | ASSERT_EXIT(do_modify_stack_chk_guard(), testing::KilledBySignal(SIGSEGV), ""); |
Nick Kralevich | dcab1b2 | 2013-01-10 17:12:29 -0800 | [diff] [blame] | 123 | } |
| 124 | |
Elliott Hughes | ad88a08 | 2012-10-24 18:37:21 -0700 | [diff] [blame] | 125 | #endif |