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zip_archive.cc
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zip_archive.cc
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/*
* Copyright (C) 2008 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.
*/
/*
* Read-only access to Zip archives, with minimal heap allocation.
*/
#define LOG_TAG "ziparchive"
#include "ziparchive/zip_archive.h"
#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
#include <limits.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#ifdef __linux__
#include <linux/fs.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#endif
#include <memory>
#include <optional>
#include <span>
#include <vector>
#if defined(__APPLE__)
#define lseek64 lseek
#endif
#if defined(__BIONIC__)
#include <android/fdsan.h>
#endif
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/macros.h> // TEMP_FAILURE_RETRY may or may not be in unistd
#include <android-base/mapped_file.h>
#include <android-base/memory.h>
#include <android-base/strings.h>
#include <android-base/utf8.h>
#include <log/log.h>
#include "entry_name_utils-inl.h"
#include "incfs_support/signal_handling.h"
#include "incfs_support/util.h"
#include "zip_archive_common.h"
#include "zip_archive_private.h"
#include "zlib.h"
// Used to turn on crc checks - verify that the content CRC matches the values
// specified in the local file header and the central directory.
static constexpr bool kCrcChecksEnabled = false;
// The maximum number of bytes to scan backwards for the EOCD start.
static const uint32_t kMaxEOCDSearch = kMaxCommentLen + sizeof(EocdRecord);
// Set a reasonable cap (256 GiB) for the zip file size. So the data is always valid when
// we parse the fields in cd or local headers as 64 bits signed integers.
static constexpr uint64_t kMaxFileLength = 256 * static_cast<uint64_t>(1u << 30u);
/*
* A Read-only Zip archive.
*
* We want "open" and "find entry by name" to be fast operations, and
* we want to use as little memory as possible. We memory-map the zip
* central directory, and load a hash table with pointers to the filenames
* (which aren't null-terminated). The other fields are at a fixed offset
* from the filename, so we don't need to extract those (but we do need
* to byte-read and endian-swap them every time we want them).
*
* It's possible that somebody has handed us a massive (~1GB) zip archive,
* so we can't expect to mmap the entire file.
*
* To speed comparisons when doing a lookup by name, we could make the mapping
* "private" (copy-on-write) and null-terminate the filenames after verifying
* the record structure. However, this requires a private mapping of
* every page that the Central Directory touches. Easier to tuck a copy
* of the string length into the hash table entry.
*/
#ifdef __linux__
static const size_t kPageSize = getpagesize();
#else
constexpr size_t kPageSize = 4096;
#endif
[[maybe_unused]] static uintptr_t pageAlignDown(uintptr_t ptr_int) {
return ptr_int & ~(kPageSize - 1);
}
[[maybe_unused]] static uintptr_t pageAlignUp(uintptr_t ptr_int) {
return pageAlignDown(ptr_int + kPageSize - 1);
}
[[maybe_unused]] static std::pair<void*, size_t> expandToPageBounds(void* ptr, size_t size) {
const auto ptr_int = reinterpret_cast<uintptr_t>(ptr);
const auto aligned_ptr_int = pageAlignDown(ptr_int);
const auto aligned_size = pageAlignUp(ptr_int + size) - aligned_ptr_int;
return {reinterpret_cast<void*>(aligned_ptr_int), aligned_size};
}
[[maybe_unused]] static void maybePrefetch([[maybe_unused]] const void* ptr,
[[maybe_unused]] size_t size) {
#ifdef __linux__
// Let's only ask for a readahead explicitly if there's enough pages to read. A regular OS
// readahead implementation would take care of the smaller requests, and it would also involve
// only a single kernel transition, just an implicit one from the page fault.
//
// Note: there's no implementation for other OSes, as the prefetch logic is highly specific
// to the memory manager, and we don't have any well defined benchmarks on Windows/Mac;
// it also mostly matters only for the cold OS boot where no files are in the page cache yet,
// but we rarely would hit this situation outside of the device startup.
auto [aligned_ptr, aligned_size] = expandToPageBounds(const_cast<void*>(ptr), size);
if (aligned_size > 32 * kPageSize) {
if (::madvise(aligned_ptr, aligned_size, MADV_WILLNEED)) {
ALOGW("Zip: madvise(file, WILLNEED) failed: %s (%d)", strerror(errno), errno);
}
}
#endif
}
[[maybe_unused]] static void maybePrepareSequentialReading([[maybe_unused]] const void* ptr,
[[maybe_unused]] size_t size) {
#ifdef __linux__
auto [aligned_ptr, aligned_size] = expandToPageBounds(const_cast<void*>(ptr), size);
if (::madvise(reinterpret_cast<void*>(aligned_ptr), aligned_size, MADV_SEQUENTIAL)) {
ALOGW("Zip: madvise(file, SEQUENTIAL) failed: %s (%d)", strerror(errno), errno);
}
#endif
}
#if defined(__BIONIC__)
static uint64_t GetOwnerTag(const ZipArchive* archive) {
return android_fdsan_create_owner_tag(ANDROID_FDSAN_OWNER_TYPE_ZIPARCHIVE,
reinterpret_cast<uint64_t>(archive));
}
#endif
ZipArchive::ZipArchive(MappedZipFile&& map, bool assume_ownership)
: mapped_zip(std::move(map)),
close_file(assume_ownership),
directory_offset(0),
central_directory(),
directory_map(),
num_entries(0) {
#if defined(__BIONIC__)
if (assume_ownership) {
CHECK(mapped_zip.GetFileDescriptor() >= 0 || !mapped_zip.GetBasePtr());
android_fdsan_exchange_owner_tag(mapped_zip.GetFileDescriptor(), 0, GetOwnerTag(this));
}
#endif
}
ZipArchive::ZipArchive(const void* address, size_t length)
: mapped_zip(address, length),
close_file(false),
directory_offset(0),
central_directory(),
directory_map(),
num_entries(0) {}
ZipArchive::~ZipArchive() {
if (close_file && mapped_zip.GetFileDescriptor() >= 0) {
#if defined(__BIONIC__)
android_fdsan_close_with_tag(mapped_zip.GetFileDescriptor(), GetOwnerTag(this));
#else
close(mapped_zip.GetFileDescriptor());
#endif
}
}
struct CentralDirectoryInfo {
uint64_t num_records;
// The size of the central directory (in bytes).
uint64_t cd_size;
// The offset of the start of the central directory, relative
// to the start of the file.
uint64_t cd_start_offset;
};
// Reads |T| at |readPtr| and increments |readPtr|. Returns std::nullopt if the boundary check
// fails.
template <typename T>
static std::optional<T> TryConsumeUnaligned(uint8_t** readPtr, const uint8_t* bufStart,
size_t bufSize) {
if (bufSize < sizeof(T) || *readPtr - bufStart > bufSize - sizeof(T)) {
ALOGW("Zip: %zu byte read exceeds the boundary of allocated buf, offset %zu, bufSize %zu",
sizeof(T), *readPtr - bufStart, bufSize);
return std::nullopt;
}
return ConsumeUnaligned<T>(readPtr);
}
static ZipError FindCentralDirectoryInfoForZip64(const char* debugFileName, ZipArchive* archive,
off64_t eocdOffset, CentralDirectoryInfo* cdInfo) {
if (eocdOffset <= sizeof(Zip64EocdLocator)) {
ALOGW("Zip: %s: Not enough space for zip64 eocd locator", debugFileName);
return kInvalidFile;
}
// We expect to find the zip64 eocd locator immediately before the zip eocd.
const int64_t locatorOffset = eocdOffset - sizeof(Zip64EocdLocator);
Zip64EocdLocator zip64EocdLocatorBuf;
const auto zip64EocdLocator = reinterpret_cast<const Zip64EocdLocator*>(
archive->mapped_zip.ReadAtOffset(reinterpret_cast<uint8_t*>((&zip64EocdLocatorBuf)),
sizeof(zip64EocdLocatorBuf), locatorOffset));
if (!zip64EocdLocator) {
ALOGW("Zip: %s: Read %zu from offset %" PRId64 " failed %s", debugFileName,
sizeof(zip64EocdLocatorBuf), locatorOffset, debugFileName);
return kIoError;
}
if (zip64EocdLocator->locator_signature != Zip64EocdLocator::kSignature) {
ALOGW("Zip: %s: Zip64 eocd locator signature not found at offset %" PRId64, debugFileName,
locatorOffset);
return kInvalidFile;
}
const int64_t zip64EocdOffset = zip64EocdLocator->zip64_eocd_offset;
if (locatorOffset <= sizeof(Zip64EocdRecord) ||
zip64EocdOffset > locatorOffset - sizeof(Zip64EocdRecord)) {
ALOGW("Zip: %s: Bad zip64 eocd offset %" PRId64 ", eocd locator offset %" PRId64, debugFileName,
zip64EocdOffset, locatorOffset);
return kInvalidOffset;
}
Zip64EocdRecord zip64EocdRecordBuf;
const auto zip64EocdRecord = reinterpret_cast<const Zip64EocdRecord*>(
archive->mapped_zip.ReadAtOffset(reinterpret_cast<uint8_t*>(&zip64EocdRecordBuf),
sizeof(zip64EocdRecordBuf), zip64EocdOffset));
if (!zip64EocdRecord) {
ALOGW("Zip: %s: read %zu from offset %" PRId64 " failed %s", debugFileName,
sizeof(zip64EocdRecordBuf), zip64EocdOffset, debugFileName);
return kIoError;
}
if (zip64EocdRecord->record_signature != Zip64EocdRecord::kSignature) {
ALOGW("Zip: %s: Zip64 eocd record signature not found at offset %" PRId64, debugFileName,
zip64EocdOffset);
return kInvalidFile;
}
if (zip64EocdOffset <= zip64EocdRecord->cd_size ||
zip64EocdRecord->cd_start_offset > zip64EocdOffset - zip64EocdRecord->cd_size) {
ALOGW("Zip: %s: Bad offset for zip64 central directory. cd offset %" PRIu64 ", cd size %" PRIu64
", zip64 eocd offset %" PRIu64,
debugFileName, zip64EocdRecord->cd_start_offset, zip64EocdRecord->cd_size,
zip64EocdOffset);
return kInvalidOffset;
}
*cdInfo = {.num_records = zip64EocdRecord->num_records,
.cd_size = zip64EocdRecord->cd_size,
.cd_start_offset = zip64EocdRecord->cd_start_offset};
return kSuccess;
}
static ZipError FindCentralDirectoryInfo(const char* debug_file_name,
ZipArchive* archive,
off64_t file_length,
std::span<uint8_t> scan_buffer,
CentralDirectoryInfo* cdInfo) {
const auto read_amount = static_cast<uint32_t>(scan_buffer.size());
const off64_t search_start = file_length - read_amount;
const auto data = archive->mapped_zip.ReadAtOffset(scan_buffer.data(), read_amount, search_start);
if (!data) {
ALOGE("Zip: read %" PRId64 " from offset %" PRId64 " failed", static_cast<int64_t>(read_amount),
static_cast<int64_t>(search_start));
return kIoError;
}
/*
* Scan backward for the EOCD magic. In an archive without a trailing
* comment, we'll find it on the first try. (We may want to consider
* doing an initial minimal read; if we don't find it, retry with a
* second read as above.)
*/
CHECK_LE(read_amount, std::numeric_limits<int32_t>::max());
int32_t i = read_amount - sizeof(EocdRecord);
for (; i >= 0; i--) {
if (data[i] == 0x50) {
const uint32_t* sig_addr = reinterpret_cast<const uint32_t*>(&data[i]);
if (android::base::get_unaligned<uint32_t>(sig_addr) == EocdRecord::kSignature) {
ALOGV("+++ Found EOCD at buf+%d", i);
break;
}
}
}
if (i < 0) {
ALOGD("Zip: EOCD not found, %s is not zip", debug_file_name);
return kInvalidFile;
}
const off64_t eocd_offset = search_start + i;
auto eocd = reinterpret_cast<const EocdRecord*>(data + i);
/*
* Verify that there's no trailing space at the end of the central directory
* and its comment.
*/
const off64_t calculated_length = eocd_offset + sizeof(EocdRecord) + eocd->comment_length;
if (calculated_length != file_length) {
ALOGW("Zip: %" PRId64 " extraneous bytes at the end of the central directory",
static_cast<int64_t>(file_length - calculated_length));
return kInvalidFile;
}
// One of the field is 0xFFFFFFFF, look for the zip64 EOCD instead.
if (eocd->num_records_on_disk == UINT16_MAX || eocd->num_records == UINT16_MAX ||
eocd->cd_size == UINT32_MAX || eocd->cd_start_offset == UINT32_MAX ||
eocd->comment_length == UINT16_MAX) {
ALOGV("Looking for the zip64 EOCD (cd_size: %" PRIu32 ", cd_start_offset: %" PRIu32
", comment_length: %" PRIu16 ", num_records: %" PRIu16 ", num_records_on_disk: %" PRIu16
")",
eocd->cd_size, eocd->cd_start_offset, eocd->comment_length, eocd->num_records,
eocd->num_records_on_disk);
return FindCentralDirectoryInfoForZip64(debug_file_name, archive, eocd_offset, cdInfo);
}
/*
* Grab the CD offset and size, and the number of entries in the
* archive and verify that they look reasonable.
*/
if (static_cast<off64_t>(eocd->cd_start_offset) + eocd->cd_size > eocd_offset) {
ALOGW("Zip: bad offsets (dir %" PRIu32 ", size %" PRIu32 ", eocd %" PRId64 ")",
eocd->cd_start_offset, eocd->cd_size, static_cast<int64_t>(eocd_offset));
return kInvalidOffset;
}
*cdInfo = {.num_records = eocd->num_records,
.cd_size = eocd->cd_size,
.cd_start_offset = eocd->cd_start_offset};
return kSuccess;
}
/*
* Find the zip Central Directory and memory-map it.
*
* On success, returns kSuccess after populating fields from the EOCD area:
* directory_offset
* directory_ptr
* num_entries
*/
static ZipError MapCentralDirectory(const char* debug_file_name, ZipArchive* archive) {
// Test file length. We want to make sure the file is small enough to be a zip
// file.
off64_t file_length = archive->mapped_zip.GetFileLength();
if (file_length == -1) {
return kInvalidFile;
}
if (file_length > kMaxFileLength) {
ALOGV("Zip: zip file too long %" PRId64, static_cast<int64_t>(file_length));
return kInvalidFile;
}
if (file_length < static_cast<off64_t>(sizeof(EocdRecord))) {
ALOGV("Zip: length %" PRId64 " is too small to be zip", static_cast<int64_t>(file_length));
return kInvalidFile;
}
/*
* Perform the traditional EOCD snipe hunt.
*
* We're searching for the End of Central Directory magic number,
* which appears at the start of the EOCD block. It's followed by
* 18 bytes of EOCD stuff and up to 64KB of archive comment. We
* need to read the last part of the file into a buffer, dig through
* it to find the magic number, parse some values out, and use those
* to determine the extent of the CD.
*
* We start by pulling in the last part of the file.
*/
const auto read_amount = uint32_t(std::min<off64_t>(file_length, kMaxEOCDSearch));
CentralDirectoryInfo cdInfo = {};
std::vector<uint8_t> scan_buffer(read_amount);
SCOPED_SIGBUS_HANDLER({
incfs::util::clearAndFree(scan_buffer);
return kIoError;
});
if (auto result = FindCentralDirectoryInfo(debug_file_name, archive,
file_length, scan_buffer, &cdInfo);
result != kSuccess) {
return result;
}
scan_buffer.clear();
if (cdInfo.num_records == 0) {
#if defined(__ANDROID__)
ALOGW("Zip: empty archive?");
#endif
return kEmptyArchive;
}
if (cdInfo.cd_size >= SIZE_MAX) {
ALOGW("Zip: The size of central directory doesn't fit in range of size_t: %" PRIu64,
cdInfo.cd_size);
return kInvalidFile;
}
ALOGV("+++ num_entries=%" PRIu64 " dir_size=%" PRIu64 " dir_offset=%" PRIu64, cdInfo.num_records,
cdInfo.cd_size, cdInfo.cd_start_offset);
// It all looks good. Create a mapping for the CD, and set the fields in archive.
if (!archive->InitializeCentralDirectory(static_cast<off64_t>(cdInfo.cd_start_offset),
static_cast<size_t>(cdInfo.cd_size))) {
return kMmapFailed;
}
archive->num_entries = cdInfo.num_records;
archive->directory_offset = cdInfo.cd_start_offset;
return kSuccess;
}
static ZipError ParseZip64ExtendedInfoInExtraField(
const uint8_t* extraFieldStart, uint16_t extraFieldLength, uint32_t zip32UncompressedSize,
uint32_t zip32CompressedSize, std::optional<uint32_t> zip32LocalFileHeaderOffset,
Zip64ExtendedInfo* zip64Info) {
if (extraFieldLength <= 4) {
ALOGW("Zip: Extra field isn't large enough to hold zip64 info, size %" PRIu16,
extraFieldLength);
return kInvalidFile;
}
// Each header MUST consist of:
// Header ID - 2 bytes
// Data Size - 2 bytes
uint16_t offset = 0;
while (offset < extraFieldLength - 4) {
auto readPtr = const_cast<uint8_t*>(extraFieldStart + offset);
auto headerId = ConsumeUnaligned<uint16_t>(&readPtr);
auto dataSize = ConsumeUnaligned<uint16_t>(&readPtr);
offset += 4;
if (dataSize > extraFieldLength - offset) {
ALOGW("Zip: Data size exceeds the boundary of extra field, data size %" PRIu16, dataSize);
return kInvalidOffset;
}
// Skip the other types of extensible data fields. Details in
// https://pkware.cachefly.net/webdocs/casestudies/APPNOTE.TXT section 4.5
if (headerId != Zip64ExtendedInfo::kHeaderId) {
offset += dataSize;
continue;
}
// Layout for Zip64 extended info (not include first 4 bytes of header)
// Original
// Size 8 bytes Original uncompressed file size
// Compressed
// Size 8 bytes Size of compressed data
// Relative Header
// Offset 8 bytes Offset of local header record
// Disk Start
// Number 4 bytes Number of the disk on which
// this file starts
if (dataSize == 8 * 3 + 4) {
ALOGW(
"Zip: Found `Disk Start Number` field in extra block. Ignoring it.");
dataSize -= 4;
}
// Sometimes, only a subset of {uncompressed size, compressed size, relative
// header offset} is presents. but golang's zip writer will write out all
// 3 even if only 1 is necessary. We should parse all 3 fields if they are
// there.
const bool completeField = dataSize == 8 * 3;
std::optional<uint64_t> uncompressedFileSize;
std::optional<uint64_t> compressedFileSize;
std::optional<uint64_t> localHeaderOffset;
if (zip32UncompressedSize == UINT32_MAX || completeField) {
uncompressedFileSize = TryConsumeUnaligned<uint64_t>(
&readPtr, extraFieldStart, extraFieldLength);
if (!uncompressedFileSize.has_value()) return kInvalidOffset;
}
if (zip32CompressedSize == UINT32_MAX || completeField) {
compressedFileSize = TryConsumeUnaligned<uint64_t>(
&readPtr, extraFieldStart, extraFieldLength);
if (!compressedFileSize.has_value()) return kInvalidOffset;
}
if (zip32LocalFileHeaderOffset == UINT32_MAX || completeField) {
localHeaderOffset = TryConsumeUnaligned<uint64_t>(
&readPtr, extraFieldStart, extraFieldLength);
if (!localHeaderOffset.has_value()) return kInvalidOffset;
}
// calculate how many bytes we read after the data size field.
size_t bytesRead = readPtr - (extraFieldStart + offset);
if (bytesRead == 0) {
ALOGW("Zip: Data size should not be 0 in zip64 extended field");
return kInvalidFile;
}
if (dataSize != bytesRead) {
auto localOffsetString = zip32LocalFileHeaderOffset.has_value()
? std::to_string(zip32LocalFileHeaderOffset.value())
: "missing";
ALOGW("Zip: Invalid data size in zip64 extended field, expect %zu , get %" PRIu16
", uncompressed size %" PRIu32 ", compressed size %" PRIu32 ", local header offset %s",
bytesRead, dataSize, zip32UncompressedSize, zip32CompressedSize,
localOffsetString.c_str());
return kInvalidFile;
}
zip64Info->uncompressed_file_size = uncompressedFileSize;
zip64Info->compressed_file_size = compressedFileSize;
zip64Info->local_header_offset = localHeaderOffset;
return kSuccess;
}
ALOGW("Zip: zip64 extended info isn't found in the extra field.");
return kInvalidFile;
}
/*
* Parses the Zip archive's Central Directory. Allocates and populates the
* hash table.
*
* Returns 0 on success.
*/
static ZipError ParseZipArchive(ZipArchive* archive) {
SCOPED_SIGBUS_HANDLER(return kIoError);
maybePrefetch(archive->central_directory.GetBasePtr(), archive->central_directory.GetMapLength());
const uint8_t* const cd_ptr = archive->central_directory.GetBasePtr();
const size_t cd_length = archive->central_directory.GetMapLength();
const uint8_t* const cd_end = cd_ptr + cd_length;
const uint64_t num_entries = archive->num_entries;
const uint8_t* ptr = cd_ptr;
uint16_t max_file_name_length = 0;
/* Walk through the central directory and verify values */
for (uint64_t i = 0; i < num_entries; i++) {
if (ptr > cd_end - sizeof(CentralDirectoryRecord)) {
ALOGW("Zip: ran off the end (item #%" PRIu64 ", %zu bytes of central directory)", i,
cd_length);
#if defined(__ANDROID__)
android_errorWriteLog(0x534e4554, "36392138");
#endif
return kInvalidFile;
}
auto cdr = reinterpret_cast<const CentralDirectoryRecord*>(ptr);
if (cdr->record_signature != CentralDirectoryRecord::kSignature) {
ALOGW("Zip: missed a central dir sig (at %" PRIu64 ")", i);
return kInvalidFile;
}
const uint16_t file_name_length = cdr->file_name_length;
const uint16_t extra_length = cdr->extra_field_length;
const uint16_t comment_length = cdr->comment_length;
const uint8_t* file_name = ptr + sizeof(CentralDirectoryRecord);
if (file_name_length >= cd_length || file_name > cd_end - file_name_length) {
ALOGW("Zip: file name for entry %" PRIu64
" exceeds the central directory range, file_name_length: %" PRIu16 ", cd_length: %zu",
i, file_name_length, cd_length);
return kInvalidEntryName;
}
max_file_name_length = std::max(max_file_name_length, file_name_length);
const uint8_t* extra_field = file_name + file_name_length;
if (extra_length >= cd_length || extra_field > cd_end - extra_length) {
ALOGW("Zip: extra field for entry %" PRIu64
" exceeds the central directory range, file_name_length: %" PRIu16 ", cd_length: %zu",
i, extra_length, cd_length);
return kInvalidFile;
}
off64_t local_header_offset = cdr->local_file_header_offset;
if (local_header_offset == UINT32_MAX) {
Zip64ExtendedInfo zip64_info{};
if (auto status = ParseZip64ExtendedInfoInExtraField(
extra_field, extra_length, cdr->uncompressed_size, cdr->compressed_size,
cdr->local_file_header_offset, &zip64_info);
status != kSuccess) {
return status;
}
CHECK(zip64_info.local_header_offset.has_value());
local_header_offset = zip64_info.local_header_offset.value();
}
if (local_header_offset >= archive->directory_offset) {
ALOGW("Zip: bad LFH offset %" PRId64 " at entry %" PRIu64,
static_cast<int64_t>(local_header_offset), i);
return kInvalidFile;
}
// Check that file name is valid UTF-8 and doesn't contain NUL (U+0000) characters.
if (!IsValidEntryName(file_name, file_name_length)) {
ALOGW("Zip: invalid file name at entry %" PRIu64, i);
return kInvalidEntryName;
}
ptr += sizeof(CentralDirectoryRecord) + file_name_length + extra_length + comment_length;
if ((ptr - cd_ptr) > static_cast<int64_t>(cd_length)) {
ALOGW("Zip: bad CD advance (%tu vs %zu) at entry %" PRIu64, ptr - cd_ptr, cd_length, i);
return kInvalidFile;
}
}
/* Create memory efficient entry map */
archive->cd_entry_map = CdEntryMapInterface::Create(num_entries, cd_length, max_file_name_length);
if (archive->cd_entry_map == nullptr) {
return kAllocationFailed;
}
/* Central directory verified, now add entries to the hash table */
ptr = cd_ptr;
for (uint64_t i = 0; i < num_entries; i++) {
auto cdr = reinterpret_cast<const CentralDirectoryRecord*>(ptr);
std::string_view entry_name{reinterpret_cast<const char*>(ptr + sizeof(*cdr)),
cdr->file_name_length};
auto add_result = archive->cd_entry_map->AddToMap(entry_name, cd_ptr);
if (add_result != 0) {
ALOGW("Zip: Error adding entry to hash table %d", add_result);
return add_result;
}
ptr += sizeof(*cdr) + cdr->file_name_length + cdr->extra_field_length + cdr->comment_length;
}
uint32_t lfh_start_bytes_buf;
auto lfh_start_bytes = reinterpret_cast<const uint32_t*>(archive->mapped_zip.ReadAtOffset(
reinterpret_cast<uint8_t*>(&lfh_start_bytes_buf), sizeof(lfh_start_bytes_buf), 0));
if (!lfh_start_bytes) {
ALOGW("Zip: Unable to read header for entry at offset == 0.");
return kInvalidFile;
}
if (*lfh_start_bytes != LocalFileHeader::kSignature) {
ALOGW("Zip: Entry at offset zero has invalid LFH signature %" PRIx32, *lfh_start_bytes);
#if defined(__ANDROID__)
android_errorWriteLog(0x534e4554, "64211847");
#endif
return kInvalidFile;
}
ALOGV("+++ zip good scan %" PRIu64 " entries", num_entries);
return kSuccess;
}
static int32_t OpenArchiveInternal(ZipArchive* archive, const char* debug_file_name) {
int32_t result = MapCentralDirectory(debug_file_name, archive);
return result != kSuccess ? result : ParseZipArchive(archive);
}
int32_t OpenArchiveFd(int fd, const char* debug_file_name, ZipArchiveHandle* handle,
bool assume_ownership) {
ZipArchive* archive = new ZipArchive(MappedZipFile(fd), assume_ownership);
*handle = archive;
return OpenArchiveInternal(archive, debug_file_name);
}
int32_t OpenArchiveFdRange(int fd, const char* debug_file_name, ZipArchiveHandle* handle,
off64_t length, off64_t offset, bool assume_ownership) {
ZipArchive* archive = new ZipArchive(MappedZipFile(fd, length, offset), assume_ownership);
*handle = archive;
if (length < 0) {
ALOGW("Invalid zip length %" PRId64, length);
return kIoError;
}
if (offset < 0) {
ALOGW("Invalid zip offset %" PRId64, offset);
return kIoError;
}
return OpenArchiveInternal(archive, debug_file_name);
}
int32_t OpenArchive(const char* fileName, ZipArchiveHandle* handle) {
const int fd = ::android::base::utf8::open(fileName, O_RDONLY | O_BINARY | O_CLOEXEC, 0);
ZipArchive* archive = new ZipArchive(MappedZipFile(fd), true);
*handle = archive;
if (fd < 0) {
ALOGW("Unable to open '%s': %s", fileName, strerror(errno));
return kIoError;
}
return OpenArchiveInternal(archive, fileName);
}
int32_t OpenArchiveFromMemory(const void* address, size_t length, const char* debug_file_name,
ZipArchiveHandle* handle) {
ZipArchive* archive = new ZipArchive(address, length);
*handle = archive;
return OpenArchiveInternal(archive, debug_file_name);
}
ZipArchiveInfo GetArchiveInfo(ZipArchiveHandle archive) {
ZipArchiveInfo result;
result.archive_size = archive->mapped_zip.GetFileLength();
result.entry_count = archive->num_entries;
return result;
}
/*
* Close a ZipArchive, closing the file and freeing the contents.
*/
void CloseArchive(ZipArchiveHandle archive) {
ALOGV("Closing archive %p", archive);
delete archive;
}
static int32_t ValidateDataDescriptor(MappedZipFile& mapped_zip, const ZipEntry64* entry) {
SCOPED_SIGBUS_HANDLER(return kIoError);
// Maximum possible size for data descriptor: 2 * 4 + 2 * 8 = 24 bytes
// The zip format doesn't specify the size of data descriptor. But we won't read OOB here even
// if the descriptor isn't present. Because the size cd + eocd in the end of the zipfile is
// larger than 24 bytes. And if the descriptor contains invalid data, we'll abort due to
// kInconsistentInformation.
uint8_t ddBuf[24];
off64_t offset = entry->offset;
if (entry->method != kCompressStored) {
offset += entry->compressed_length;
} else {
offset += entry->uncompressed_length;
}
const auto ddPtr = mapped_zip.ReadAtOffset(ddBuf, sizeof(ddBuf), offset);
if (!ddPtr) {
return kIoError;
}
const uint32_t ddSignature = *(reinterpret_cast<const uint32_t*>(ddPtr));
const uint8_t* ddReadPtr = (ddSignature == DataDescriptor::kOptSignature) ? ddPtr + 4 : ddPtr;
DataDescriptor descriptor{};
descriptor.crc32 = ConsumeUnaligned<uint32_t>(&ddReadPtr);
// Don't use entry->zip64_format_size, because that is set to true even if
// both compressed/uncompressed size are < 0xFFFFFFFF.
constexpr auto u32max = std::numeric_limits<uint32_t>::max();
if (entry->compressed_length >= u32max ||
entry->uncompressed_length >= u32max) {
descriptor.compressed_size = ConsumeUnaligned<uint64_t>(&ddReadPtr);
descriptor.uncompressed_size = ConsumeUnaligned<uint64_t>(&ddReadPtr);
} else {
descriptor.compressed_size = ConsumeUnaligned<uint32_t>(&ddReadPtr);
descriptor.uncompressed_size = ConsumeUnaligned<uint32_t>(&ddReadPtr);
}
// Validate that the values in the data descriptor match those in the central
// directory.
if (entry->compressed_length != descriptor.compressed_size ||
entry->uncompressed_length != descriptor.uncompressed_size ||
entry->crc32 != descriptor.crc32) {
ALOGW("Zip: size/crc32 mismatch. expected {%" PRIu64 ", %" PRIu64 ", %" PRIx32
"}, was {%" PRIu64 ", %" PRIu64 ", %" PRIx32 "}",
entry->compressed_length, entry->uncompressed_length, entry->crc32,
descriptor.compressed_size, descriptor.uncompressed_size, descriptor.crc32);
return kInconsistentInformation;
}
return 0;
}
static int32_t FindEntry(const ZipArchive* archive, std::string_view entryName,
const uint64_t nameOffset, ZipEntry64* data) {
std::vector<uint8_t> buffer;
SCOPED_SIGBUS_HANDLER({
incfs::util::clearAndFree(buffer);
return kIoError;
});
// Recover the start of the central directory entry from the filename
// pointer. The filename is the first entry past the fixed-size data,
// so we can just subtract back from that.
const uint8_t* base_ptr = archive->central_directory.GetBasePtr();
const uint8_t* ptr = base_ptr + nameOffset;
ptr -= sizeof(CentralDirectoryRecord);
// This is the base of our mmapped region, we have to check that
// the name that's in the hash table is a pointer to a location within
// this mapped region.
if (ptr < base_ptr || ptr > base_ptr + archive->central_directory.GetMapLength()) {
ALOGW("Zip: Invalid entry pointer");
return kInvalidOffset;
}
auto cdr = reinterpret_cast<const CentralDirectoryRecord*>(ptr);
// The offset of the start of the central directory in the zipfile.
// We keep this lying around so that we can check all our lengths
// and our per-file structures.
const off64_t cd_offset = archive->directory_offset;
// Fill out the compression method, modification time, crc32
// and other interesting attributes from the central directory. These
// will later be compared against values from the local file header.
data->method = cdr->compression_method;
data->mod_time = cdr->last_mod_date << 16 | cdr->last_mod_time;
data->crc32 = cdr->crc32;
data->compressed_length = cdr->compressed_size;
data->uncompressed_length = cdr->uncompressed_size;
// Figure out the local header offset from the central directory. The
// actual file data will begin after the local header and the name /
// extra comments.
off64_t local_header_offset = cdr->local_file_header_offset;
// One of the info field is UINT32_MAX, try to parse the real value in the zip64 extended info in
// the extra field.
if (cdr->uncompressed_size == UINT32_MAX || cdr->compressed_size == UINT32_MAX ||
cdr->local_file_header_offset == UINT32_MAX) {
const uint8_t* extra_field = ptr + sizeof(CentralDirectoryRecord) + cdr->file_name_length;
Zip64ExtendedInfo zip64_info{};
if (auto status = ParseZip64ExtendedInfoInExtraField(
extra_field, cdr->extra_field_length, cdr->uncompressed_size, cdr->compressed_size,
cdr->local_file_header_offset, &zip64_info);
status != kSuccess) {
return status;
}
data->uncompressed_length = zip64_info.uncompressed_file_size.value_or(cdr->uncompressed_size);
data->compressed_length = zip64_info.compressed_file_size.value_or(cdr->compressed_size);
local_header_offset = zip64_info.local_header_offset.value_or(local_header_offset);
data->zip64_format_size =
cdr->uncompressed_size == UINT32_MAX || cdr->compressed_size == UINT32_MAX;
}
off64_t local_header_end;
if (__builtin_add_overflow(local_header_offset, sizeof(LocalFileHeader), &local_header_end) ||
local_header_end >= cd_offset) {
// We tested >= because the name that follows can't be zero length.
ALOGW("Zip: bad local hdr offset in zip");
return kInvalidOffset;
}
uint8_t lfh_buf[sizeof(LocalFileHeader)];
const auto lfh = reinterpret_cast<const LocalFileHeader*>(
archive->mapped_zip.ReadAtOffset(lfh_buf, sizeof(lfh_buf), local_header_offset));
if (!lfh) {
ALOGW("Zip: failed reading lfh name from offset %" PRId64,
static_cast<int64_t>(local_header_offset));
return kIoError;
}
if (lfh->lfh_signature != LocalFileHeader::kSignature) {
ALOGW("Zip: didn't find signature at start of lfh, offset=%" PRId64,
static_cast<int64_t>(local_header_offset));
return kInvalidOffset;
}
// Check that the local file header name matches the declared name in the central directory.
CHECK_LE(entryName.size(), UINT16_MAX);
auto name_length = static_cast<uint16_t>(entryName.size());
if (lfh->file_name_length != name_length) {
ALOGW("Zip: lfh name length did not match central directory for %s: %" PRIu16 " %" PRIu16,
std::string(entryName).c_str(), lfh->file_name_length, name_length);
return kInconsistentInformation;
}
off64_t name_offset;
if (__builtin_add_overflow(local_header_offset, sizeof(LocalFileHeader), &name_offset)) {
ALOGW("Zip: lfh name offset invalid");
return kInvalidOffset;
}
off64_t name_end;
if (__builtin_add_overflow(name_offset, name_length, &name_end) || name_end > cd_offset) {
// We tested > cd_offset here because the file data that follows can be zero length.
ALOGW("Zip: lfh name length invalid");
return kInvalidOffset;
}
// An optimization: get enough memory on the stack to be able to use it later without an extra
// allocation when reading the zip64 extended info. Reasonable names should be under half the
// MAX_PATH (256 chars), and Zip64 header size is 32 bytes; archives often have some other extras,
// e.g. alignment, so 128 bytes is outght to be enough for (almost) anybody. If it's not we'll
// reallocate later anyway.
uint8_t static_buf[128];
auto name_buf = static_buf;
if (name_length > std::size(static_buf)) {
buffer.resize(name_length);
name_buf = buffer.data();
}
const auto read_name = archive->mapped_zip.ReadAtOffset(name_buf, name_length, name_offset);
if (!read_name) {
ALOGW("Zip: failed reading lfh name from offset %" PRId64, static_cast<int64_t>(name_offset));
return kIoError;
}
if (memcmp(entryName.data(), read_name, name_length) != 0) {
ALOGW("Zip: lfh name did not match central directory");
return kInconsistentInformation;
}
// Check the extra field length, regardless of whether it's used, or what it's used for.
const off64_t lfh_extra_field_offset = name_offset + lfh->file_name_length;
const uint16_t lfh_extra_field_size = lfh->extra_field_length;
if (lfh_extra_field_offset > cd_offset - lfh_extra_field_size) {
ALOGW("Zip: extra field has a bad size for entry %s", std::string(entryName).c_str());
return kInvalidOffset;
}
data->extra_field_size = lfh_extra_field_size;
// Check whether the extra field is being used for zip64.
uint64_t lfh_uncompressed_size = lfh->uncompressed_size;
uint64_t lfh_compressed_size = lfh->compressed_size;
if (lfh_uncompressed_size == UINT32_MAX || lfh_compressed_size == UINT32_MAX) {
if (lfh_uncompressed_size != UINT32_MAX || lfh_compressed_size != UINT32_MAX) {
ALOGW(
"Zip: zip64 on Android requires both compressed and uncompressed length to be "
"UINT32_MAX");
return kInvalidFile;
}
auto lfh_extra_field_buf = static_buf;
if (lfh_extra_field_size > std::size(static_buf)) {
// Make sure vector won't try to copy existing data if it needs to reallocate.
buffer.clear();
buffer.resize(lfh_extra_field_size);
lfh_extra_field_buf = buffer.data();
}
const auto local_extra_field = archive->mapped_zip.ReadAtOffset(
lfh_extra_field_buf, lfh_extra_field_size, lfh_extra_field_offset);
if (!local_extra_field) {
ALOGW("Zip: failed reading lfh extra field from offset %" PRId64, lfh_extra_field_offset);
return kIoError;
}
Zip64ExtendedInfo zip64_info{};
if (auto status = ParseZip64ExtendedInfoInExtraField(
local_extra_field, lfh_extra_field_size, lfh->uncompressed_size, lfh->compressed_size,
std::nullopt, &zip64_info);
status != kSuccess) {
return status;
}
CHECK(zip64_info.uncompressed_file_size.has_value());
CHECK(zip64_info.compressed_file_size.has_value());
lfh_uncompressed_size = zip64_info.uncompressed_file_size.value();
lfh_compressed_size = zip64_info.compressed_file_size.value();
}
// Paranoia: Match the values specified in the local file header
// to those specified in the central directory.
// Warn if central directory and local file header don't agree on the use
// of a trailing Data Descriptor. The reference implementation is inconsistent
// and appears to use the LFH value during extraction (unzip) but the CD value
// while displayng information about archives (zipinfo). The spec remains
// silent on this inconsistency as well.
//
// For now, always use the version from the LFH but make sure that the values
// specified in the central directory match those in the data descriptor.
//
// NOTE: It's also worth noting that unzip *does* warn about inconsistencies in
// bit 11 (EFS: The language encoding flag, marking that filename and comment are
// encoded using UTF-8). This implementation does not check for the presence of
// that flag and always enforces that entry names are valid UTF-8.
if ((lfh->gpb_flags & kGPBDDFlagMask) != (cdr->gpb_flags & kGPBDDFlagMask)) {
ALOGW("Zip: gpb flag mismatch at bit 3. expected {%04" PRIx16 "}, was {%04" PRIx16 "}",
cdr->gpb_flags, lfh->gpb_flags);
}
// If there is no trailing data descriptor, verify that the central directory and local file
// header agree on the crc, compressed, and uncompressed sizes of the entry.
if ((lfh->gpb_flags & kGPBDDFlagMask) == 0) {
data->has_data_descriptor = 0;
if (data->compressed_length != lfh_compressed_size ||
data->uncompressed_length != lfh_uncompressed_size || data->crc32 != lfh->crc32) {
ALOGW("Zip: size/crc32 mismatch. expected {%" PRIu64 ", %" PRIu64 ", %" PRIx32
"}, was {%" PRIu64 ", %" PRIu64 ", %" PRIx32 "}",
data->compressed_length, data->uncompressed_length, data->crc32, lfh_compressed_size,
lfh_uncompressed_size, lfh->crc32);
return kInconsistentInformation;
}
} else {
data->has_data_descriptor = 1;
}
// 4.4.2.1: the upper byte of `version_made_by` gives the source OS. Unix is 3.