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/*
* Copyright (C) 2016 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.
*/
#include "vdex_file.h"
#include <sys/mman.h> // For the PROT_* and MAP_* constants.
#include <sys/stat.h> // for mkdir()
#include <memory>
#include <unordered_set>
#include <android-base/logging.h>
#include <android-base/stringprintf.h>
#include <log/log.h>
#include "base/bit_utils.h"
#include "base/leb128.h"
#include "base/stl_util.h"
#include "base/systrace.h"
#include "base/unix_file/fd_file.h"
#include "base/zip_archive.h"
#include "class_linker.h"
#include "class_loader_context.h"
#include "dex/art_dex_file_loader.h"
#include "dex/class_accessor-inl.h"
#include "dex/dex_file_loader.h"
#include "gc/heap.h"
#include "gc/space/image_space.h"
#include "mirror/class-inl.h"
#include "quicken_info.h"
#include "handle_scope-inl.h"
#include "runtime.h"
#include "verifier/verifier_deps.h"
namespace art {
using android::base::StringPrintf;
constexpr uint8_t VdexFile::VdexFileHeader::kVdexInvalidMagic[4];
constexpr uint8_t VdexFile::VdexFileHeader::kVdexMagic[4];
constexpr uint8_t VdexFile::VdexFileHeader::kVdexVersion[4];
bool VdexFile::VdexFileHeader::IsMagicValid() const {
return (memcmp(magic_, kVdexMagic, sizeof(kVdexMagic)) == 0);
}
bool VdexFile::VdexFileHeader::IsVdexVersionValid() const {
return (memcmp(vdex_version_, kVdexVersion, sizeof(kVdexVersion)) == 0);
}
VdexFile::VdexFileHeader::VdexFileHeader(bool has_dex_section ATTRIBUTE_UNUSED)
: number_of_sections_(static_cast<uint32_t>(VdexSection::kNumberOfSections)) {
memcpy(magic_, kVdexMagic, sizeof(kVdexMagic));
memcpy(vdex_version_, kVdexVersion, sizeof(kVdexVersion));
DCHECK(IsMagicValid());
DCHECK(IsVdexVersionValid());
}
std::unique_ptr<VdexFile> VdexFile::OpenAtAddress(uint8_t* mmap_addr,
size_t mmap_size,
bool mmap_reuse,
const std::string& vdex_filename,
bool writable,
bool low_4gb,
std::string* error_msg) {
ScopedTrace trace(("VdexFile::OpenAtAddress " + vdex_filename).c_str());
if (!OS::FileExists(vdex_filename.c_str())) {
*error_msg = "File " + vdex_filename + " does not exist.";
return nullptr;
}
std::unique_ptr<File> vdex_file;
if (writable) {
vdex_file.reset(OS::OpenFileReadWrite(vdex_filename.c_str()));
} else {
vdex_file.reset(OS::OpenFileForReading(vdex_filename.c_str()));
}
if (vdex_file == nullptr) {
*error_msg = "Could not open file " + vdex_filename +
(writable ? " for read/write" : "for reading");
return nullptr;
}
int64_t vdex_length = vdex_file->GetLength();
if (vdex_length == -1) {
*error_msg = "Could not read the length of file " + vdex_filename;
return nullptr;
}
return OpenAtAddress(mmap_addr,
mmap_size,
mmap_reuse,
vdex_file->Fd(),
vdex_length,
vdex_filename,
writable,
low_4gb,
error_msg);
}
std::unique_ptr<VdexFile> VdexFile::OpenAtAddress(uint8_t* mmap_addr,
size_t mmap_size,
bool mmap_reuse,
int file_fd,
size_t vdex_length,
const std::string& vdex_filename,
bool writable,
bool low_4gb,
std::string* error_msg) {
if (mmap_addr != nullptr && mmap_size < vdex_length) {
*error_msg = StringPrintf("Insufficient pre-allocated space to mmap vdex: %zu and %zu",
mmap_size,
vdex_length);
return nullptr;
}
CHECK_IMPLIES(mmap_reuse, mmap_addr != nullptr);
// Start as PROT_WRITE so we can mprotect back to it if we want to.
MemMap mmap = MemMap::MapFileAtAddress(
mmap_addr,
vdex_length,
PROT_READ | PROT_WRITE,
writable ? MAP_SHARED : MAP_PRIVATE,
file_fd,
/* start= */ 0u,
low_4gb,
vdex_filename.c_str(),
mmap_reuse,
/* reservation= */ nullptr,
error_msg);
if (!mmap.IsValid()) {
*error_msg = "Failed to mmap file " + vdex_filename + " : " + *error_msg;
return nullptr;
}
std::unique_ptr<VdexFile> vdex(new VdexFile(std::move(mmap)));
if (!vdex->IsValid()) {
*error_msg = "Vdex file is not valid";
return nullptr;
}
return vdex;
}
std::unique_ptr<VdexFile> VdexFile::OpenFromDm(const std::string& filename,
const ZipArchive& archive) {
std::string error_msg;
std::unique_ptr<ZipEntry> zip_entry(archive.Find(VdexFile::kVdexNameInDmFile, &error_msg));
if (zip_entry == nullptr) {
LOG(INFO) << "No " << VdexFile::kVdexNameInDmFile << " file in DexMetadata archive. "
<< "Not doing fast verification.";
return nullptr;
}
MemMap input_file = zip_entry->MapDirectlyOrExtract(
filename.c_str(),
VdexFile::kVdexNameInDmFile,
&error_msg,
alignof(VdexFile));
if (!input_file.IsValid()) {
LOG(WARNING) << "Could not open vdex file in DexMetadata archive: " << error_msg;
return nullptr;
}
std::unique_ptr<VdexFile> vdex_file = std::make_unique<VdexFile>(std::move(input_file));
if (!vdex_file->IsValid()) {
LOG(WARNING) << "The dex metadata .vdex is not valid. Ignoring it.";
return nullptr;
}
if (vdex_file->HasDexSection()) {
LOG(ERROR) << "The dex metadata is not allowed to contain dex files";
android_errorWriteLog(0x534e4554, "178055795"); // Report to SafetyNet.
return nullptr;
}
return vdex_file;
}
const uint8_t* VdexFile::GetNextDexFileData(const uint8_t* cursor, uint32_t dex_file_index) const {
DCHECK(cursor == nullptr || (cursor > Begin() && cursor <= End()));
if (cursor == nullptr) {
// Beginning of the iteration, return the first dex file if there is one.
return HasDexSection() ? DexBegin() : nullptr;
} else if (dex_file_index >= GetNumberOfDexFiles()) {
return nullptr;
} else {
// Fetch the next dex file. Return null if there is none.
const uint8_t* data = cursor + reinterpret_cast<const DexFile::Header*>(cursor)->file_size_;
// Dex files are required to be 4 byte aligned. the OatWriter makes sure they are, see
// OatWriter::SeekToDexFiles.
return AlignUp(data, 4);
}
}
const uint8_t* VdexFile::GetNextTypeLookupTableData(const uint8_t* cursor,
uint32_t dex_file_index) const {
if (cursor == nullptr) {
// Beginning of the iteration, return the first dex file if there is one.
return HasTypeLookupTableSection() ? TypeLookupTableDataBegin() : nullptr;
} else if (dex_file_index >= GetNumberOfDexFiles()) {
return nullptr;
} else {
const uint8_t* data = cursor + sizeof(uint32_t) + reinterpret_cast<const uint32_t*>(cursor)[0];
// TypeLookupTables are required to be 4 byte aligned. the OatWriter makes sure they are.
// We don't check this here to be defensive against corrupted vdex files.
// Callers should check the returned value matches their expectations.
return data;
}
}
bool VdexFile::OpenAllDexFiles(std::vector<std::unique_ptr<const DexFile>>* dex_files,
std::string* error_msg) const {
const ArtDexFileLoader dex_file_loader;
size_t i = 0;
for (const uint8_t* dex_file_start = GetNextDexFileData(nullptr, i);
dex_file_start != nullptr;
dex_file_start = GetNextDexFileData(dex_file_start, ++i)) {
size_t size = reinterpret_cast<const DexFile::Header*>(dex_file_start)->file_size_;
// TODO: Supply the location information for a vdex file.
static constexpr char kVdexLocation[] = "";
std::string location = DexFileLoader::GetMultiDexLocation(i, kVdexLocation);
std::unique_ptr<const DexFile> dex(dex_file_loader.OpenWithDataSection(
dex_file_start,
size,
/*data_base=*/ nullptr,
/*data_size=*/ 0u,
location,
GetLocationChecksum(i),
/*oat_dex_file=*/ nullptr,
/*verify=*/ false,
/*verify_checksum=*/ false,
error_msg));
if (dex == nullptr) {
return false;
}
dex_files->push_back(std::move(dex));
}
return true;
}
static bool CreateDirectories(const std::string& child_path, /* out */ std::string* error_msg) {
size_t last_slash_pos = child_path.find_last_of('/');
CHECK_NE(last_slash_pos, std::string::npos) << "Invalid path: " << child_path;
std::string parent_path = child_path.substr(0, last_slash_pos);
if (OS::DirectoryExists(parent_path.c_str())) {
return true;
} else if (CreateDirectories(parent_path, error_msg)) {
if (mkdir(parent_path.c_str(), 0700) == 0) {
return true;
}
*error_msg = "Could not create directory " + parent_path;
return false;
} else {
return false;
}
}
bool VdexFile::WriteToDisk(const std::string& path,
const std::vector<const DexFile*>& dex_files,
const verifier::VerifierDeps& verifier_deps,
std::string* error_msg) {
std::vector<uint8_t> verifier_deps_data;
verifier_deps.Encode(dex_files, &verifier_deps_data);
uint32_t verifier_deps_size = verifier_deps_data.size();
// Add padding so the type lookup tables are 4 byte aligned.
uint32_t verifier_deps_with_padding_size = RoundUp(verifier_deps_data.size(), 4);
DCHECK_GE(verifier_deps_with_padding_size, verifier_deps_data.size());
verifier_deps_data.resize(verifier_deps_with_padding_size, 0);
size_t type_lookup_table_size = 0u;
for (const DexFile* dex_file : dex_files) {
type_lookup_table_size +=
sizeof(uint32_t) + TypeLookupTable::RawDataLength(dex_file->NumClassDefs());
}
VdexFile::VdexFileHeader vdex_header(/* has_dex_section= */ false);
VdexFile::VdexSectionHeader sections[static_cast<uint32_t>(VdexSection::kNumberOfSections)];
// Set checksum section.
sections[VdexSection::kChecksumSection].section_kind = VdexSection::kChecksumSection;
sections[VdexSection::kChecksumSection].section_offset = GetChecksumsOffset();
sections[VdexSection::kChecksumSection].section_size =
sizeof(VdexFile::VdexChecksum) * dex_files.size();
// Set dex section.
sections[VdexSection::kDexFileSection].section_kind = VdexSection::kDexFileSection;
sections[VdexSection::kDexFileSection].section_offset = 0u;
sections[VdexSection::kDexFileSection].section_size = 0u;
// Set VerifierDeps section.
sections[VdexSection::kVerifierDepsSection].section_kind = VdexSection::kVerifierDepsSection;
sections[VdexSection::kVerifierDepsSection].section_offset =
GetChecksumsOffset() + sections[kChecksumSection].section_size;
sections[VdexSection::kVerifierDepsSection].section_size = verifier_deps_size;
// Set TypeLookupTable section.
sections[VdexSection::kTypeLookupTableSection].section_kind =
VdexSection::kTypeLookupTableSection;
sections[VdexSection::kTypeLookupTableSection].section_offset =
sections[VdexSection::kVerifierDepsSection].section_offset + verifier_deps_with_padding_size;
sections[VdexSection::kTypeLookupTableSection].section_size = type_lookup_table_size;
if (!CreateDirectories(path, error_msg)) {
return false;
}
std::unique_ptr<File> out(OS::CreateEmptyFileWriteOnly(path.c_str()));
if (out == nullptr) {
*error_msg = "Could not open " + path + " for writing";
return false;
}
// Write header.
if (!out->WriteFully(reinterpret_cast<const char*>(&vdex_header), sizeof(vdex_header))) {
*error_msg = "Could not write vdex header to " + path;
out->Unlink();
return false;
}
// Write section infos.
if (!out->WriteFully(reinterpret_cast<const char*>(&sections), sizeof(sections))) {
*error_msg = "Could not write vdex sections to " + path;
out->Unlink();
return false;
}
// Write checksum section.
for (const DexFile* dex_file : dex_files) {
uint32_t checksum = dex_file->GetLocationChecksum();
const uint32_t* checksum_ptr = &checksum;
static_assert(sizeof(*checksum_ptr) == sizeof(VdexFile::VdexChecksum));
if (!out->WriteFully(reinterpret_cast<const char*>(checksum_ptr),
sizeof(VdexFile::VdexChecksum))) {
*error_msg = "Could not write dex checksums to " + path;
out->Unlink();
return false;
}
}
if (!out->WriteFully(reinterpret_cast<const char*>(verifier_deps_data.data()),
verifier_deps_with_padding_size)) {
*error_msg = "Could not write verifier deps to " + path;
out->Unlink();
return false;
}
size_t written_type_lookup_table_size = 0;
for (const DexFile* dex_file : dex_files) {
TypeLookupTable type_lookup_table = TypeLookupTable::Create(*dex_file);
uint32_t size = type_lookup_table.RawDataLength();
DCHECK_ALIGNED(size, 4);
if (!out->WriteFully(reinterpret_cast<const char*>(&size), sizeof(uint32_t)) ||
!out->WriteFully(reinterpret_cast<const char*>(type_lookup_table.RawData()), size)) {
*error_msg = "Could not write type lookup table " + path;
out->Unlink();
return false;
}
written_type_lookup_table_size += sizeof(uint32_t) + size;
}
DCHECK_EQ(written_type_lookup_table_size, type_lookup_table_size);
if (out->FlushClose() != 0) {
*error_msg = "Could not flush and close " + path;
out->Unlink();
return false;
}
return true;
}
bool VdexFile::MatchesDexFileChecksums(const std::vector<const DexFile::Header*>& dex_headers)
const {
if (dex_headers.size() != GetNumberOfDexFiles()) {
LOG(WARNING) << "Mismatch of number of dex files in vdex (expected="
<< GetNumberOfDexFiles() << ", actual=" << dex_headers.size() << ")";
return false;
}
const VdexChecksum* checksums = GetDexChecksumsArray();
for (size_t i = 0; i < dex_headers.size(); ++i) {
if (checksums[i] != dex_headers[i]->checksum_) {
LOG(WARNING) << "Mismatch of dex file checksum in vdex (index=" << i << ")";
return false;
}
}
return true;
}
static ObjPtr<mirror::Class> FindClassAndClearException(ClassLinker* class_linker,
Thread* self,
const char* name,
Handle<mirror::ClassLoader> class_loader)
REQUIRES_SHARED(Locks::mutator_lock_) {
ObjPtr<mirror::Class> result = class_linker->FindClass(self, name, class_loader);
if (result == nullptr) {
DCHECK(self->IsExceptionPending());
self->ClearException();
}
return result;
}
static const char* GetStringFromId(const DexFile& dex_file,
dex::StringIndex string_id,
uint32_t number_of_extra_strings,
const uint32_t* extra_strings_offsets,
const uint8_t* verifier_deps) {
uint32_t num_ids_in_dex = dex_file.NumStringIds();
if (string_id.index_ < num_ids_in_dex) {
return dex_file.StringDataByIdx(string_id);
} else {
CHECK_LT(string_id.index_ - num_ids_in_dex, number_of_extra_strings);
uint32_t offset = extra_strings_offsets[string_id.index_ - num_ids_in_dex];
return reinterpret_cast<const char*>(verifier_deps) + offset;
}
}
// Returns an array of offsets where the assignability checks for each class
// definition are stored.
static const uint32_t* GetDexFileClassDefs(const uint8_t* verifier_deps, uint32_t index) {
uint32_t dex_file_offset = reinterpret_cast<const uint32_t*>(verifier_deps)[index];
return reinterpret_cast<const uint32_t*>(verifier_deps + dex_file_offset);
}
// Returns an array of offsets where extra strings are stored.
static const uint32_t* GetExtraStringsOffsets(const DexFile& dex_file,
const uint8_t* verifier_deps,
const uint32_t* dex_file_class_defs,
/*out*/ uint32_t* number_of_extra_strings) {
// The information for strings is right after dex_file_class_defs, 4-byte
// aligned
uint32_t end_of_assignability_types = dex_file_class_defs[dex_file.NumClassDefs()];
const uint8_t* strings_data_start =
AlignUp(verifier_deps + end_of_assignability_types, sizeof(uint32_t));
// First entry is the number of extra strings for this dex file.
*number_of_extra_strings = *reinterpret_cast<const uint32_t*>(strings_data_start);
// Then an array of offsets in `verifier_deps` for the extra strings.
return reinterpret_cast<const uint32_t*>(strings_data_start + sizeof(uint32_t));
}
ClassStatus VdexFile::ComputeClassStatus(Thread* self, Handle<mirror::Class> cls) const {
const DexFile& dex_file = cls->GetDexFile();
uint16_t class_def_index = cls->GetDexClassDefIndex();
// Find which dex file index from within the vdex file.
uint32_t index = 0;
for (; index < GetNumberOfDexFiles(); ++index) {
if (dex_file.GetLocationChecksum() == GetLocationChecksum(index)) {
break;
}
}
DCHECK_NE(index, GetNumberOfDexFiles());
const uint8_t* verifier_deps = GetVerifierDepsData().data();
const uint32_t* dex_file_class_defs = GetDexFileClassDefs(verifier_deps, index);
// Fetch type checks offsets.
uint32_t class_def_offset = dex_file_class_defs[class_def_index];
if (class_def_offset == verifier::VerifierDeps::kNotVerifiedMarker) {
// Return a status that needs re-verification.
return ClassStatus::kResolved;
}
// End offset for this class's type checks. We know there is one and the loop
// will terminate.
uint32_t end_offset = verifier::VerifierDeps::kNotVerifiedMarker;
for (uint32_t i = class_def_index + 1; i < dex_file.NumClassDefs() + 1; ++i) {
end_offset = dex_file_class_defs[i];
if (end_offset != verifier::VerifierDeps::kNotVerifiedMarker) {
break;
}
}
DCHECK_NE(end_offset, verifier::VerifierDeps::kNotVerifiedMarker);
uint32_t number_of_extra_strings = 0;
// Offset where extra strings are stored.
const uint32_t* extra_strings_offsets = GetExtraStringsOffsets(dex_file,
verifier_deps,
dex_file_class_defs,
&number_of_extra_strings);
// Loop over and perform each assignability check.
StackHandleScope<3> hs(self);
ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
Handle<mirror::ClassLoader> class_loader(hs.NewHandle(cls->GetClassLoader()));
MutableHandle<mirror::Class> source(hs.NewHandle<mirror::Class>(nullptr));
MutableHandle<mirror::Class> destination(hs.NewHandle<mirror::Class>(nullptr));
const uint8_t* cursor = verifier_deps + class_def_offset;
const uint8_t* end = verifier_deps + end_offset;
while (cursor < end) {
uint32_t destination_index;
uint32_t source_index;
if (UNLIKELY(!DecodeUnsignedLeb128Checked(&cursor, end, &destination_index) ||
!DecodeUnsignedLeb128Checked(&cursor, end, &source_index))) {
// Error parsing the data, just return that we are not verified.
return ClassStatus::kResolved;
}
const char* destination_desc = GetStringFromId(dex_file,
dex::StringIndex(destination_index),
number_of_extra_strings,
extra_strings_offsets,
verifier_deps);
destination.Assign(
FindClassAndClearException(class_linker, self, destination_desc, class_loader));
const char* source_desc = GetStringFromId(dex_file,
dex::StringIndex(source_index),
number_of_extra_strings,
extra_strings_offsets,
verifier_deps);
source.Assign(FindClassAndClearException(class_linker, self, source_desc, class_loader));
if (destination == nullptr || source == nullptr) {
// The interpreter / compiler can handle a missing class.
continue;
}
DCHECK(destination->IsResolved() && source->IsResolved());
if (!destination->IsAssignableFrom(source.Get())) {
VLOG(verifier) << "Vdex checking failed for " << cls->PrettyClass()
<< ": expected " << destination->PrettyClass()
<< " to be assignable from " << source->PrettyClass();
// An implicit assignability check is failing in the code, return that the
// class is not verified.
return ClassStatus::kResolved;
}
}
return ClassStatus::kVerifiedNeedsAccessChecks;
}
} // namespace art