platform_bionic/tests/stack_protector_test.cpp
Mitch Phillips 7ce3ec389b Disable stack protector test with stack MTE
Obviously stack MTE conflates with the stack protector test. It doesn't
conflate with heap MTE (which we're expecting to push more broadly as
part of the -eng build), and so we want to keep this test working under
heap-mte scenarios as well.

Hence, the check-if-stack-variable-is-tagged test, and only under that
case, we skip.

Test: atest bionic-unit-tests on a fullmte device (with stack MTE turned
back on and the new compiler).
Bug: 320448268

Change-Id: I2ecee8a7c46416883235bf5c4ee2de9408047829
2024-01-22 12:40:34 +01:00

144 lines
4.1 KiB
C++

/*
* Copyright (C) 2012 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.
*/
/*
* Contributed by: Intel Corporation
*/
#include <gtest/gtest.h>
#include <pthread.h>
#include <stdint.h>
#include <stdio.h>
#include <unistd.h>
#include <set>
#include <android-base/silent_death_test.h>
#include "platform/bionic/mte.h"
#include "private/bionic_tls.h"
extern "C" pid_t gettid(); // glibc defines this but doesn't declare it anywhere.
#if defined(__BIONIC__)
extern uintptr_t __stack_chk_guard;
#endif
struct stack_protector_checker {
std::set<pid_t> tids;
std::set<void*> guards;
void Check() {
pid_t tid = gettid();
void* guard = __get_tls()[TLS_SLOT_STACK_GUARD];
printf("[thread %d] TLS stack guard = %p\n", tid, guard);
// Duplicate tid. gettid(2) bug? Seeing this would be very upsetting.
ASSERT_TRUE(tids.find(tid) == tids.end());
// Uninitialized guard. Our bug. Note this is potentially flaky; we _could_
// get four random zero bytes, but it should be vanishingly unlikely.
ASSERT_NE(guard, nullptr);
#if defined(__BIONIC__)
// bionic always has the global too.
ASSERT_EQ(__stack_chk_guard, reinterpret_cast<uintptr_t>(guard));
#endif
tids.insert(tid);
guards.insert(guard);
}
};
TEST(stack_protector, same_guard_per_thread) {
// Everyone has the TLS slot set, even if their stack protector
// implementation doesn't yet use it.
stack_protector_checker checker;
// Check the main thread.
ASSERT_EQ(getpid(), gettid()); // We are the main thread, right?
checker.Check();
size_t thread_count = 9;
for (size_t i = 1; i < thread_count; ++i) {
pthread_t t;
ASSERT_EQ(0, pthread_create(&t, nullptr, [](void* arg) -> void* {
stack_protector_checker* checker = reinterpret_cast<stack_protector_checker*>(arg);
checker->Check();
return nullptr;
}, &checker));
void* result;
ASSERT_EQ(0, pthread_join(t, &result));
ASSERT_EQ(nullptr, result);
}
ASSERT_EQ(thread_count, checker.tids.size());
// Both bionic and glibc use the same guard for every thread.
ASSERT_EQ(1U, checker.guards.size());
}
TEST(stack_protector, global_guard) {
#if defined(__BIONIC__)
// Bionic always has a global, even if it's using TLS.
ASSERT_NE(0, gettid());
ASSERT_NE(0U, __stack_chk_guard);
#else
GTEST_SKIP() << "glibc doesn't have a global __stack_chk_guard";
#endif
}
// Make sure that a stack variable (`*p`) is tagged under MTE, by forcing the
// stack safety analysis to fail.
int z;
__attribute__((noinline)) void escape_stack_safety_analysis(int* p) {
*p = z;
}
bool stack_mte_enabled() {
if (!mte_supported()) return false;
int stack_variable;
escape_stack_safety_analysis(&stack_variable);
#if defined(__aarch64__)
return reinterpret_cast<uintptr_t>(&stack_variable) & (0xfull << 56);
#else // !defined(__aarch64__)
return false;
#endif // defined(__aarch64__)
}
bool hwasan_enabled() {
#if __has_feature(hwaddress_sanitizer)
return true;
#else
return false;
#endif // __has_feature(hwaddress_sanitizer)
}
using stack_protector_DeathTest = SilentDeathTest;
TEST_F(stack_protector_DeathTest, modify_stack_protector) {
// In another file to prevent inlining, which removes stack protection.
extern void modify_stack_protector_test();
if (stack_mte_enabled()) {
GTEST_SKIP() << "Stack MTE is enabled, stack protector is not available";
} else if (hwasan_enabled()) {
ASSERT_EXIT(modify_stack_protector_test(), testing::KilledBySignal(SIGABRT), "tag-mismatch");
} else {
ASSERT_EXIT(modify_stack_protector_test(), testing::KilledBySignal(SIGABRT),
"stack corruption detected");
}
}