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/*
* Copyright (C) 2018 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 "idmap2d/Idmap2Service.h"
#include <sys/stat.h> // umask
#include <sys/types.h> // umask
#include <unistd.h>
#include <cerrno>
#include <cstring>
#include <fstream>
#include <memory>
#include <ostream>
#include <string>
#include "android-base/macros.h"
#include "android-base/stringprintf.h"
#include "binder/IPCThreadState.h"
#include "idmap2/BinaryStreamVisitor.h"
#include "idmap2/FileUtils.h"
#include "idmap2/Idmap.h"
#include "idmap2/Result.h"
#include "idmap2/SysTrace.h"
#include "idmap2/ZipFile.h"
#include "utils/String8.h"
using android::IPCThreadState;
using android::base::StringPrintf;
using android::binder::Status;
using android::idmap2::BinaryStreamVisitor;
using android::idmap2::GetPackageCrc;
using android::idmap2::Idmap;
using android::idmap2::IdmapHeader;
using android::idmap2::ZipFile;
using android::idmap2::utils::kIdmapCacheDir;
using android::idmap2::utils::kIdmapFilePermissionMask;
using android::idmap2::utils::UidHasWriteAccessToPath;
using PolicyBitmask = android::ResTable_overlayable_policy_header::PolicyBitmask;
namespace {
constexpr const char* kFrameworkPath = "/system/framework/framework-res.apk";
Status ok() {
return Status::ok();
}
Status error(const std::string& msg) {
LOG(ERROR) << msg;
return Status::fromExceptionCode(Status::EX_NONE, msg.c_str());
}
PolicyBitmask ConvertAidlArgToPolicyBitmask(int32_t arg) {
return static_cast<PolicyBitmask>(arg);
}
Status GetCrc(const std::string& apk_path, uint32_t* out_crc) {
const auto zip = ZipFile::Open(apk_path);
if (!zip) {
return error(StringPrintf("failed to open apk %s", apk_path.c_str()));
}
const auto crc = GetPackageCrc(*zip);
if (!crc) {
return error(crc.GetErrorMessage());
}
*out_crc = *crc;
return ok();
}
} // namespace
namespace android::os {
Status Idmap2Service::getIdmapPath(const std::string& overlay_apk_path,
int32_t user_id ATTRIBUTE_UNUSED, std::string* _aidl_return) {
assert(_aidl_return);
SYSTRACE << "Idmap2Service::getIdmapPath " << overlay_apk_path;
*_aidl_return = Idmap::CanonicalIdmapPathFor(kIdmapCacheDir, overlay_apk_path);
return ok();
}
Status Idmap2Service::removeIdmap(const std::string& overlay_apk_path,
int32_t user_id ATTRIBUTE_UNUSED, bool* _aidl_return) {
assert(_aidl_return);
SYSTRACE << "Idmap2Service::removeIdmap " << overlay_apk_path;
const uid_t uid = IPCThreadState::self()->getCallingUid();
const std::string idmap_path = Idmap::CanonicalIdmapPathFor(kIdmapCacheDir, overlay_apk_path);
if (!UidHasWriteAccessToPath(uid, idmap_path)) {
*_aidl_return = false;
return error(base::StringPrintf("failed to unlink %s: calling uid %d lacks write access",
idmap_path.c_str(), uid));
}
if (unlink(idmap_path.c_str()) != 0) {
*_aidl_return = false;
return error("failed to unlink " + idmap_path + ": " + strerror(errno));
}
*_aidl_return = true;
return ok();
}
Status Idmap2Service::verifyIdmap(const std::string& target_apk_path,
const std::string& overlay_apk_path, int32_t fulfilled_policies,
bool enforce_overlayable, int32_t user_id ATTRIBUTE_UNUSED,
bool* _aidl_return) {
SYSTRACE << "Idmap2Service::verifyIdmap " << overlay_apk_path;
assert(_aidl_return);
const std::string idmap_path = Idmap::CanonicalIdmapPathFor(kIdmapCacheDir, overlay_apk_path);
std::ifstream fin(idmap_path);
const std::unique_ptr<const IdmapHeader> header = IdmapHeader::FromBinaryStream(fin);
fin.close();
if (!header) {
*_aidl_return = false;
return error("failed to parse idmap header");
}
uint32_t target_crc;
if (target_apk_path == kFrameworkPath && android_crc_) {
target_crc = *android_crc_;
} else {
auto target_crc_status = GetCrc(target_apk_path, &target_crc);
if (!target_crc_status.isOk()) {
*_aidl_return = false;
return target_crc_status;
}
// Loading the framework zip can take several milliseconds. Cache the crc of the framework
// resource APK to reduce repeated work during boot.
if (target_apk_path == kFrameworkPath) {
android_crc_ = target_crc;
}
}
uint32_t overlay_crc;
auto overlay_crc_status = GetCrc(overlay_apk_path, &overlay_crc);
if (!overlay_crc_status.isOk()) {
*_aidl_return = false;
return overlay_crc_status;
}
auto up_to_date =
header->IsUpToDate(target_apk_path.c_str(), overlay_apk_path.c_str(), target_crc, overlay_crc,
ConvertAidlArgToPolicyBitmask(fulfilled_policies), enforce_overlayable);
*_aidl_return = static_cast<bool>(up_to_date);
return *_aidl_return ? ok() : error(up_to_date.GetErrorMessage());
}
Status Idmap2Service::createIdmap(const std::string& target_apk_path,
const std::string& overlay_apk_path, int32_t fulfilled_policies,
bool enforce_overlayable, int32_t user_id ATTRIBUTE_UNUSED,
aidl::nullable<std::string>* _aidl_return) {
assert(_aidl_return);
SYSTRACE << "Idmap2Service::createIdmap " << target_apk_path << " " << overlay_apk_path;
_aidl_return->reset();
const PolicyBitmask policy_bitmask = ConvertAidlArgToPolicyBitmask(fulfilled_policies);
const std::string idmap_path = Idmap::CanonicalIdmapPathFor(kIdmapCacheDir, overlay_apk_path);
const uid_t uid = IPCThreadState::self()->getCallingUid();
if (!UidHasWriteAccessToPath(uid, idmap_path)) {
return error(base::StringPrintf("will not write to %s: calling uid %d lacks write accesss",
idmap_path.c_str(), uid));
}
const std::unique_ptr<const ApkAssets> target_apk = ApkAssets::Load(target_apk_path);
if (!target_apk) {
return error("failed to load apk " + target_apk_path);
}
const std::unique_ptr<const ApkAssets> overlay_apk = ApkAssets::Load(overlay_apk_path);
if (!overlay_apk) {
return error("failed to load apk " + overlay_apk_path);
}
const auto idmap =
Idmap::FromApkAssets(*target_apk, *overlay_apk, policy_bitmask, enforce_overlayable);
if (!idmap) {
return error(idmap.GetErrorMessage());
}
// idmap files are mapped with mmap in libandroidfw. Deleting and recreating the idmap guarantees
// that existing memory maps will continue to be valid and unaffected.
unlink(idmap_path.c_str());
umask(kIdmapFilePermissionMask);
std::ofstream fout(idmap_path);
if (fout.fail()) {
return error("failed to open idmap path " + idmap_path);
}
BinaryStreamVisitor visitor(fout);
(*idmap)->accept(&visitor);
fout.close();
if (fout.fail()) {
unlink(idmap_path.c_str());
return error("failed to write to idmap path " + idmap_path);
}
*_aidl_return = aidl::make_nullable<std::string>(idmap_path);
return ok();
}
} // namespace android::os
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