135 lines
		
	
	
		
			3.9 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			135 lines
		
	
	
		
			3.9 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 "BionicDeathTest.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 <unistd.h>
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#include <set>
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extern "C" pid_t gettid();
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// For x86, bionic and glibc have per-thread stack guard values (all identical).
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#if defined(__i386__)
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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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#endif // __i386__
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TEST(stack_protector, same_guard_per_thread) {
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#if defined(__i386__)
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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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#else // __i386__
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  GTEST_LOG_(INFO) << "This test does nothing.\n";
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#endif // __i386__
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}
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// For ARM and MIPS, glibc has a global stack check guard value.
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#if defined(__BIONIC__) || defined(__arm__) || defined(__mips__)
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#define TEST_STACK_CHK_GUARD
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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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/*
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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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static char* dummy_buf;
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__attribute__ ((noinline))
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static void do_modify_stack_chk_guard() {
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  char buf[128];
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  // Store local array's address to global variable to force compiler to generate stack guards.
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  dummy_buf = buf;
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  __stack_chk_guard = 0x12345678;
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}
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#endif
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TEST(stack_protector, global_guard) {
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#if defined(TEST_STACK_CHK_GUARD)
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  ASSERT_NE(0, gettid());
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  ASSERT_NE(0U, __stack_chk_guard);
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#else // TEST_STACK_CHK_GUARD
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  GTEST_LOG_(INFO) << "This test does nothing.\n";
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#endif // TEST_STACK_CHK_GUARD
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}
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class stack_protector_DeathTest : public BionicDeathTest {};
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TEST_F(stack_protector_DeathTest, modify_stack_protector) {
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#if defined(TEST_STACK_CHK_GUARD)
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  ASSERT_EXIT(do_modify_stack_chk_guard(), testing::KilledBySignal(SIGABRT), "");
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#else // TEST_STACK_CHK_GUARD
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  GTEST_LOG_(INFO) << "This test does nothing.\n";
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#endif // TEST_STACK_CHK_GUARD
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}
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