128 lines
3.5 KiB
C++
128 lines
3.5 KiB
C++
/*
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* Copyright (C) 2012 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/*
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* Contributed by: Intel Corporation
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*/
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#include <gtest/gtest.h>
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#include <pthread.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <sys/syscall.h>
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#include <unistd.h>
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#include <set>
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#ifdef __GLIBC__
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// glibc doesn't expose gettid(2).
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pid_t gettid() { return syscall(__NR_gettid); }
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#endif
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#ifdef __i386__
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// For x86, bionic and glibc have per-thread stack guard values (all identical).
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static uint32_t GetGuardFromTls() {
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uint32_t guard;
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asm ("mov %%gs:0x14, %0": "=d" (guard));
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return guard;
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}
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struct stack_protector_checker {
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std::set<pid_t> tids;
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std::set<uint32_t> guards;
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void Check() {
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pid_t tid = gettid();
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uint32_t guard = GetGuardFromTls();
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printf("[thread %d] %%gs:0x14 = 0x%08x\n", tid, guard);
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// Duplicate tid. gettid(2) bug? Seeing this would be very upsetting.
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ASSERT_TRUE(tids.find(tid) == tids.end());
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// Uninitialized guard. Our bug. Note this is potentially flaky; we _could_ get
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// four random zero bytes, but it should be vanishingly unlikely.
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ASSERT_NE(guard, 0U);
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tids.insert(tid);
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guards.insert(guard);
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}
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};
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static void* ThreadGuardHelper(void* arg) {
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stack_protector_checker* checker = reinterpret_cast<stack_protector_checker*>(arg);
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checker->Check();
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return NULL;
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}
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TEST(stack_protector, same_guard_per_thread) {
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stack_protector_checker checker;
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size_t thread_count = 10;
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for (size_t i = 0; i < thread_count; ++i) {
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pthread_t t;
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ASSERT_EQ(0, pthread_create(&t, NULL, ThreadGuardHelper, &checker));
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void* result;
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ASSERT_EQ(0, pthread_join(t, &result));
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ASSERT_EQ(NULL, result);
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}
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ASSERT_EQ(thread_count, checker.tids.size());
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// bionic and glibc use the same guard for every thread.
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ASSERT_EQ(1U, checker.guards.size());
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}
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#endif
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#if defined(__BIONIC__) || defined(__arm__) || defined(__mips__)
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// For ARM and MIPS, glibc has a global stack check guard value.
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// Bionic has the global for x86 too, to support binaries that can run on
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// Android releases that didn't implement the TLS guard value.
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extern "C" uintptr_t __stack_chk_guard;
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TEST(stack_protector, global_guard) {
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ASSERT_NE(0, gettid());
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ASSERT_NE(0U, __stack_chk_guard);
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}
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/*
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* When this function returns, the stack canary will be inconsistent
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* with the previous value, which will generate a call to __stack_chk_fail(),
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* eventually resulting in a SIGABRT.
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*
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* This must be marked with "__attribute__ ((noinline))", to ensure the
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* compiler generates the proper stack guards around this function.
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*/
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__attribute__ ((noinline))
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static void do_modify_stack_chk_guard() {
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__stack_chk_guard = 0x12345678;
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}
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// We have to say "DeathTest" here so gtest knows to run this test (which exits)
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// in its own process.
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TEST(stack_protector_DeathTest, modify_stack_protector) {
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::testing::FLAGS_gtest_death_test_style = "threadsafe";
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ASSERT_EXIT(do_modify_stack_chk_guard(), testing::KilledBySignal(SIGABRT), "");
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}
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#endif
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