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// Copyright 2019 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifdef UNSAFE_BUFFERS_BUILD
// TODO(crbug.com/390223051): Remove C-library calls to fix the errors.
#pragma allow_unsafe_libc_calls
#endif
#include "components/gwp_asan/crash_handler/crash_analyzer.h"
#include <cstdint>
#include <limits>
#include <memory>
#include <string>
#include <utility>
#include <vector>
#include "base/containers/span.h"
#include "base/debug/stack_trace.h"
#include "base/functional/callback_helpers.h"
#include "base/test/gtest_util.h"
#include "base/test/metrics/histogram_tester.h"
#include "build/build_config.h"
#include "components/gwp_asan/client/guarded_page_allocator.h"
#include "components/gwp_asan/client/gwp_asan.h"
#include "components/gwp_asan/client/lightweight_detector/poison_metadata_recorder.h"
#include "components/gwp_asan/common/allocator_state.h"
#include "components/gwp_asan/common/crash_key_name.h"
#include "components/gwp_asan/common/lightweight_detector_state.h"
#include "components/gwp_asan/crash_handler/crash.pb.h"
#include "testing/gmock/include/gmock/gmock.h"
#include "testing/gtest/include/gtest/gtest.h"
#include "third_party/crashpad/crashpad/client/annotation.h"
#include "third_party/crashpad/crashpad/snapshot/annotation_snapshot.h"
#include "third_party/crashpad/crashpad/snapshot/cpu_architecture.h"
#include "third_party/crashpad/crashpad/snapshot/cpu_context.h"
#include "third_party/crashpad/crashpad/snapshot/test/test_exception_snapshot.h"
#include "third_party/crashpad/crashpad/snapshot/test/test_module_snapshot.h"
#include "third_party/crashpad/crashpad/snapshot/test/test_process_snapshot.h"
#include "third_party/crashpad/crashpad/test/process_type.h"
#include "third_party/crashpad/crashpad/util/process/process_memory_native.h"
#if BUILDFLAG(IS_ANDROID) || BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS)
#include "third_party/crashpad/crashpad/test/linux/fake_ptrace_connection.h"
#endif
namespace gwp_asan {
namespace internal {
namespace {
void SetNonCanonicalAccessAddress(
crashpad::test::TestExceptionSnapshot& exception,
crashpad::VMAddress address) {
#if defined(ARCH_CPU_X86_64)
auto* context = exception.MutableContext();
context->architecture = crashpad::kCPUArchitectureX86_64;
memset(context->x86_64, 0, sizeof(*context->x86_64));
#endif // defined(ARCH_CPU_X86_64)
#if BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS) || BUILDFLAG(IS_ANDROID)
exception.SetException(SIGSEGV);
#if defined(ARCH_CPU_X86_64)
exception.SetExceptionInfo(SI_KERNEL);
exception.SetExceptionAddress(0);
context->x86_64->rax = address;
#else // defined(ARCH_CPU_X86_64)
exception.SetExceptionAddress(address);
#endif // defined(ARCH_CPU_X86_64)
#elif BUILDFLAG(IS_APPLE)
exception.SetException(EXC_BAD_ACCESS);
#if defined(ARCH_CPU_X86_64)
exception.SetExceptionInfo(EXC_I386_GPFLT);
exception.SetExceptionAddress(0);
context->x86_64->rax = address;
#else // defined(ARCH_CPU_X86_64)
exception.SetExceptionAddress(address);
#endif // defined(ARCH_CPU_X86_64)
#elif BUILDFLAG(IS_WIN)
exception.SetException(EXCEPTION_ACCESS_VIOLATION);
#if defined(ARCH_CPU_X86_64)
exception.SetCodes({0, std::numeric_limits<uint64_t>::max()});
context->x86_64->rax = address;
#else // defined(ARCH_CPU_X86_64)
exception.SetCodes({0, address});
#endif // defined(ARCH_CPU_X86_64)
#else
#error "Unknown platform"
#endif
}
constexpr const char* kMallocHistogramName =
"Security.GwpAsan.CrashAnalysisResult.Malloc";
constexpr const char* kPartitionAllocHistogramName =
"Security.GwpAsan.CrashAnalysisResult.PartitionAlloc";
} // namespace
class BaseCrashAnalyzerTest : public testing::Test {
protected:
BaseCrashAnalyzerTest(bool is_partition_alloc,
LightweightDetectorMode lightweight_detector_mode)
: is_partition_alloc_(is_partition_alloc),
lightweight_detector_mode_(lightweight_detector_mode) {}
void SetUp() override {
ASSERT_TRUE(gpa_.Init(
AllocatorSettings{
.max_allocated_pages = 1u,
.num_metadata = 1u,
.total_pages = 1u,
.sampling_frequency = 0u,
},
base::DoNothing(), is_partition_alloc_));
if (lightweight_detector_mode_ != LightweightDetectorMode::kOff) {
lud::PoisonMetadataRecorder::ResetForTesting();
lud::PoisonMetadataRecorder::Init(lightweight_detector_mode_, 1);
}
}
// Initializes the ProcessSnapshot so that it appears the given allocator was
// used for backing either malloc or PartitionAlloc, depending on
// `is_partition_alloc_`.
void InitializeSnapshot(crashpad::VMAddress exception_address) {
std::vector<crashpad::AnnotationSnapshot> annotations;
auto append_annotation = [&](const char* key, const std::string& value) {
std::vector<uint8_t> buffer(value.begin(), value.end());
annotations.emplace_back(
key, static_cast<uint16_t>(crashpad::Annotation::Type::kString),
buffer);
};
append_annotation(
is_partition_alloc_ ? kPartitionAllocCrashKey : kMallocCrashKey,
gpa_.GetCrashKey());
if (lightweight_detector_mode_ != LightweightDetectorMode::kOff) {
append_annotation(kLightweightDetectorCrashKey,
lud::PoisonMetadataRecorder::Get()->GetCrashKey());
}
auto module = std::make_unique<crashpad::test::TestModuleSnapshot>();
module->SetAnnotationObjects(annotations);
auto exception = std::make_unique<crashpad::test::TestExceptionSnapshot>();
// Just match the bitness, the actual architecture doesn't matter.
#if defined(ARCH_CPU_64_BITS)
exception->MutableContext()->architecture =
crashpad::CPUArchitecture::kCPUArchitectureX86_64;
#else
exception->MutableContext()->architecture =
crashpad::CPUArchitecture::kCPUArchitectureX86;
#endif
SetNonCanonicalAccessAddress(*exception, exception_address);
#if BUILDFLAG(IS_ANDROID) || BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS)
ASSERT_TRUE(connection_.Initialize(getpid()));
auto memory = std::make_unique<crashpad::ProcessMemoryLinux>(&connection_);
#else
auto memory = std::make_unique<crashpad::ProcessMemoryNative>();
ASSERT_TRUE(memory->Initialize(crashpad::test::GetSelfProcess()));
#endif // BUILDFLAG(IS_ANDROID) || BUILDFLAG(IS_LINUX) ||
// BUILDFLAG(IS_CHROMEOS)
process_snapshot_.AddModule(std::move(module));
process_snapshot_.SetException(std::move(exception));
process_snapshot_.SetProcessMemory(std::move(memory));
}
GuardedPageAllocator gpa_;
crashpad::test::TestProcessSnapshot process_snapshot_;
#if BUILDFLAG(IS_ANDROID) || BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS)
crashpad::test::FakePtraceConnection connection_;
#endif
bool is_partition_alloc_;
LightweightDetectorMode lightweight_detector_mode_;
};
class CrashAnalyzerTest : public BaseCrashAnalyzerTest {
protected:
CrashAnalyzerTest()
: BaseCrashAnalyzerTest(/* is_partition_alloc = */ false,
LightweightDetectorMode::kOff) {
InitializeSnapshot(0);
}
};
// Stack trace collection on Android builds with frame pointers enabled does
// not use base::debug::StackTrace, so the stack traces may vary slightly and
// break this test.
#if !BUILDFLAG(IS_ANDROID) || !BUILDFLAG(CAN_UNWIND_WITH_FRAME_POINTERS)
// TODO(https://crbug.com/340586138): Disabled due to excessive flakiness.
TEST_F(CrashAnalyzerTest, DISABLED_StackTraceCollection) {
void* ptr = gpa_.Allocate(10);
ASSERT_NE(ptr, nullptr);
gpa_.Deallocate(ptr);
// Lets pretend a double free() occurred on the allocation we saw previously.
gpa_.state_.double_free_address = reinterpret_cast<uintptr_t>(ptr);
base::HistogramTester histogram_tester;
gwp_asan::Crash proto;
bool proto_present =
CrashAnalyzer::GetExceptionInfo(process_snapshot_, &proto);
ASSERT_TRUE(proto_present);
int result = static_cast<int>(GwpAsanCrashAnalysisResult::kGwpAsanCrash);
EXPECT_THAT(histogram_tester.GetAllSamples(kMallocHistogramName),
testing::ElementsAre(base::Bucket(result, 1)));
histogram_tester.ExpectTotalCount(kPartitionAllocHistogramName, 0);
ASSERT_TRUE(proto.has_allocation());
ASSERT_TRUE(proto.has_deallocation());
base::debug::StackTrace st;
base::span<const void* const> trace = st.addresses();
ASSERT_FALSE(trace.empty());
// Adjust the stack trace to point to the entry above the current frame.
while (!trace.empty()) {
if (trace[0] == __builtin_return_address(0))
break;
trace = trace.subspan<1>();
}
ASSERT_GT(proto.allocation().stack_trace_size(),
static_cast<int>(trace.size()));
ASSERT_GT(proto.deallocation().stack_trace_size(),
static_cast<int>(trace.size()));
// Ensure that the allocation and deallocation stack traces match the stack
// frames that we collected above the current frame.
for (size_t i = 1; i <= trace.size(); i++) {
SCOPED_TRACE(i);
ASSERT_EQ(proto.allocation().stack_trace(
proto.allocation().stack_trace_size() - i),
reinterpret_cast<uintptr_t>(trace[trace.size() - i]));
ASSERT_EQ(proto.deallocation().stack_trace(
proto.deallocation().stack_trace_size() - i),
reinterpret_cast<uintptr_t>(trace[trace.size() - i]));
}
EXPECT_EQ(proto.mode(), Crash_Mode_CLASSIC);
}
#endif
TEST_F(CrashAnalyzerTest, InternalError) {
// Lets pretend an invalid free() occurred in the allocator region.
gpa_.state_.free_invalid_address =
reinterpret_cast<uintptr_t>(gpa_.state_.first_page_addr);
// Out of bounds slot_to_metadata_idx, allocator was initialized with only a
// single entry slot/metadata entry.
gpa_.slot_to_metadata_idx_[0] = 5;
base::HistogramTester histogram_tester;
gwp_asan::Crash proto;
bool proto_present =
CrashAnalyzer::GetExceptionInfo(process_snapshot_, &proto);
ASSERT_TRUE(proto_present);
int result =
static_cast<int>(GwpAsanCrashAnalysisResult::kErrorBadMetadataIndex);
EXPECT_THAT(histogram_tester.GetAllSamples(kMallocHistogramName),
testing::ElementsAre(base::Bucket(result, 1)));
histogram_tester.ExpectTotalCount(kPartitionAllocHistogramName, 0);
EXPECT_TRUE(proto.has_internal_error());
ASSERT_TRUE(proto.has_missing_metadata());
EXPECT_TRUE(proto.missing_metadata());
EXPECT_EQ(proto.mode(), Crash_Mode_CLASSIC);
}
// The detector is not used on 32-bit systems because pointers there aren't big
// enough to safely store metadata IDs.
#if defined(ARCH_CPU_64_BITS)
class LightweightDetectorAnalyzerTest
: public BaseCrashAnalyzerTest,
public testing::WithParamInterface<LightweightDetectorMode> {
protected:
LightweightDetectorAnalyzerTest()
: BaseCrashAnalyzerTest(/* is_partition_alloc = */ true, GetParam()) {}
};
extern Crash_Mode LightweightDetectorModeToGwpAsanMode(
LightweightDetectorMode mode);
TEST_P(LightweightDetectorAnalyzerTest, UseAfterFree) {
uint64_t alloc;
ASSERT_TRUE(lud::PoisonMetadataRecorder::Get());
lud::PoisonMetadataRecorder::Get()->RecordAndZap(&alloc, sizeof(alloc));
InitializeSnapshot(alloc);
base::HistogramTester histogram_tester;
gwp_asan::Crash proto;
bool proto_present =
CrashAnalyzer::GetExceptionInfo(process_snapshot_, &proto);
ASSERT_TRUE(proto_present);
int result =
static_cast<int>(GwpAsanCrashAnalysisResult::kLightweightDetectorCrash);
EXPECT_THAT(histogram_tester.GetAllSamples(kPartitionAllocHistogramName),
testing::ElementsAre(base::Bucket(result, 1)));
histogram_tester.ExpectTotalCount(kMallocHistogramName, 0);
ASSERT_FALSE(proto.has_allocation());
ASSERT_TRUE(proto.has_deallocation());
EXPECT_FALSE(proto.has_internal_error());
ASSERT_TRUE(proto.has_missing_metadata());
EXPECT_FALSE(proto.missing_metadata());
EXPECT_EQ(proto.mode(),
CrashAnalyzer::LightweightDetectorModeToGwpAsanMode(GetParam()));
}
TEST_P(LightweightDetectorAnalyzerTest, InternalError) {
uint64_t alloc;
lud::PoisonMetadataRecorder::Get()->RecordAndZap(&alloc, sizeof(alloc));
InitializeSnapshot(alloc);
// Corrupt the metadata ID.
++lud::PoisonMetadataRecorder::Get()->metadata_[0].id;
base::HistogramTester histogram_tester;
gwp_asan::Crash proto;
bool proto_present =
CrashAnalyzer::GetExceptionInfo(process_snapshot_, &proto);
ASSERT_TRUE(proto_present);
int result =
static_cast<int>(GwpAsanCrashAnalysisResult::
kErrorInvalidOrOutdatedLightweightMetadataIndex);
EXPECT_THAT(histogram_tester.GetAllSamples(kPartitionAllocHistogramName),
testing::ElementsAre(base::Bucket(result, 1)));
histogram_tester.ExpectTotalCount(kMallocHistogramName, 0);
ASSERT_FALSE(proto.has_allocation());
ASSERT_FALSE(proto.has_deallocation());
EXPECT_TRUE(proto.has_internal_error());
ASSERT_TRUE(proto.has_missing_metadata());
EXPECT_TRUE(proto.missing_metadata());
EXPECT_EQ(proto.mode(),
CrashAnalyzer::LightweightDetectorModeToGwpAsanMode(GetParam()));
}
INSTANTIATE_TEST_SUITE_P(
VaryLightweightDetectorMode,
LightweightDetectorAnalyzerTest,
testing::Values(LightweightDetectorMode::kBrpQuarantine,
LightweightDetectorMode::kRandom));
#endif // defined(ARCH_CPU_64_BITS)
} // namespace internal
} // namespace gwp_asan
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