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/*
* Copyright (C) 2019 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 specic language governing permissions and
* limitations under the License.
*/
#include "MediaProviderWrapper.h"
#include "libfuse_jni/ReaddirHelper.h"
#include <android-base/logging.h>
#include <android-base/properties.h>
#include <jni.h>
#include <nativehelper/scoped_local_ref.h>
#include <nativehelper/scoped_primitive_array.h>
#include <nativehelper/scoped_utf_chars.h>
#include <pthread.h>
#include <mutex>
#include <unordered_map>
namespace mediaprovider {
namespace fuse {
using android::base::GetBoolProperty;
using std::string;
namespace {
constexpr const char* kPropRedactionEnabled = "persist.sys.fuse.redaction-enabled";
constexpr uid_t ROOT_UID = 0;
constexpr uid_t SHELL_UID = 2000;
/** Private helper functions **/
inline bool shouldBypassMediaProvider(uid_t uid) {
return uid == SHELL_UID || uid == ROOT_UID;
}
static bool CheckForJniException(JNIEnv* env) {
if (env->ExceptionCheck()) {
env->ExceptionDescribe();
env->ExceptionClear();
return true;
}
return false;
}
std::unique_ptr<RedactionInfo> getRedactionInfoInternal(JNIEnv* env, jobject media_provider_object,
jmethodID mid_get_redaction_ranges,
uid_t uid, pid_t tid, const string& path) {
ScopedLocalRef<jstring> j_path(env, env->NewStringUTF(path.c_str()));
ScopedLocalRef<jlongArray> redaction_ranges_local_ref(
env, static_cast<jlongArray>(env->CallObjectMethod(
media_provider_object, mid_get_redaction_ranges, j_path.get(), uid, tid)));
ScopedLongArrayRO redaction_ranges(env, redaction_ranges_local_ref.get());
if (CheckForJniException(env)) {
return nullptr;
}
std::unique_ptr<RedactionInfo> ri;
if (redaction_ranges.size() % 2) {
LOG(ERROR) << "Error while calculating redaction ranges: array length is uneven";
} else if (redaction_ranges.size() > 0) {
ri = std::make_unique<RedactionInfo>(redaction_ranges.size() / 2, redaction_ranges.get());
} else {
// No ranges to redact
ri = std::make_unique<RedactionInfo>();
}
return ri;
}
int insertFileInternal(JNIEnv* env, jobject media_provider_object, jmethodID mid_insert_file,
const string& path, uid_t uid) {
ScopedLocalRef<jstring> j_path(env, env->NewStringUTF(path.c_str()));
int res = env->CallIntMethod(media_provider_object, mid_insert_file, j_path.get(), uid);
if (CheckForJniException(env)) {
return EFAULT;
}
return res;
}
int deleteFileInternal(JNIEnv* env, jobject media_provider_object, jmethodID mid_delete_file,
const string& path, uid_t uid) {
ScopedLocalRef<jstring> j_path(env, env->NewStringUTF(path.c_str()));
int res = env->CallIntMethod(media_provider_object, mid_delete_file, j_path.get(), uid);
if (CheckForJniException(env)) {
return EFAULT;
}
return res;
}
int isOpenAllowedInternal(JNIEnv* env, jobject media_provider_object, jmethodID mid_is_open_allowed,
const string& path, uid_t uid, bool for_write) {
ScopedLocalRef<jstring> j_path(env, env->NewStringUTF(path.c_str()));
int res = env->CallIntMethod(media_provider_object, mid_is_open_allowed, j_path.get(), uid,
for_write);
if (CheckForJniException(env)) {
return EFAULT;
}
return res;
}
void scanFileInternal(JNIEnv* env, jobject media_provider_object, jmethodID mid_scan_file,
const string& path) {
ScopedLocalRef<jstring> j_path(env, env->NewStringUTF(path.c_str()));
env->CallVoidMethod(media_provider_object, mid_scan_file, j_path.get());
CheckForJniException(env);
}
int isMkdirOrRmdirAllowedInternal(JNIEnv* env, jobject media_provider_object,
jmethodID mid_is_mkdir_or_rmdir_allowed, const string& path,
uid_t uid, bool forCreate) {
ScopedLocalRef<jstring> j_path(env, env->NewStringUTF(path.c_str()));
int res = env->CallIntMethod(media_provider_object, mid_is_mkdir_or_rmdir_allowed, j_path.get(),
uid, forCreate);
if (CheckForJniException(env)) {
return EFAULT;
}
return res;
}
int isOpendirAllowedInternal(JNIEnv* env, jobject media_provider_object,
jmethodID mid_is_opendir_allowed, const string& path, uid_t uid,
bool forWrite) {
ScopedLocalRef<jstring> j_path(env, env->NewStringUTF(path.c_str()));
int res = env->CallIntMethod(media_provider_object, mid_is_opendir_allowed, j_path.get(), uid,
forWrite);
if (CheckForJniException(env)) {
return EFAULT;
}
return res;
}
bool isUidForPackageInternal(JNIEnv* env, jobject media_provider_object,
jmethodID mid_is_uid_for_package, const string& pkg, uid_t uid) {
ScopedLocalRef<jstring> j_pkg(env, env->NewStringUTF(pkg.c_str()));
bool res = env->CallBooleanMethod(media_provider_object, mid_is_uid_for_package, j_pkg.get(),
uid);
if (CheckForJniException(env)) {
return false;
}
return res;
}
std::vector<std::shared_ptr<DirectoryEntry>> getFilesInDirectoryInternal(
JNIEnv* env, jobject media_provider_object, jmethodID mid_get_files_in_dir, uid_t uid,
const string& path) {
std::vector<std::shared_ptr<DirectoryEntry>> directory_entries;
ScopedLocalRef<jstring> j_path(env, env->NewStringUTF(path.c_str()));
ScopedLocalRef<jobjectArray> files_list(
env, static_cast<jobjectArray>(env->CallObjectMethod(
media_provider_object, mid_get_files_in_dir, j_path.get(), uid)));
if (CheckForJniException(env)) {
directory_entries.push_back(std::make_shared<DirectoryEntry>("", EFAULT));
return directory_entries;
}
int de_count = env->GetArrayLength(files_list.get());
if (de_count == 1) {
ScopedLocalRef<jstring> j_d_name(env,
(jstring)env->GetObjectArrayElement(files_list.get(), 0));
ScopedUtfChars d_name(env, j_d_name.get());
if (d_name.c_str() == nullptr) {
LOG(ERROR) << "Error reading file name returned from MediaProvider at index " << 0;
directory_entries.push_back(std::make_shared<DirectoryEntry>("", EFAULT));
return directory_entries;
} else if (d_name.c_str()[0] == '\0') {
// Calling package has no storage permissions.
directory_entries.push_back(std::make_shared<DirectoryEntry>("", EPERM));
return directory_entries;
}
}
for (int i = 0; i < de_count; i++) {
ScopedLocalRef<jstring> j_d_name(env,
(jstring)env->GetObjectArrayElement(files_list.get(), i));
ScopedUtfChars d_name(env, j_d_name.get());
if (d_name.c_str() == nullptr) {
LOG(ERROR) << "Error reading file name returned from MediaProvider at index " << i;
directory_entries.resize(0);
directory_entries.push_back(std::make_shared<DirectoryEntry>("", EFAULT));
break;
}
directory_entries.push_back(std::make_shared<DirectoryEntry>(d_name.c_str(), DT_REG));
}
return directory_entries;
}
int renameInternal(JNIEnv* env, jobject media_provider_object, jmethodID mid_rename,
const string& old_path, const string& new_path, uid_t uid) {
ScopedLocalRef<jstring> j_old_path(env, env->NewStringUTF(old_path.c_str()));
ScopedLocalRef<jstring> j_new_path(env, env->NewStringUTF(new_path.c_str()));
int res = env->CallIntMethod(media_provider_object, mid_rename, j_old_path.get(),
j_new_path.get(), uid);
if (CheckForJniException(env)) {
return EFAULT;
}
return res;
}
void onFileCreatedInternal(JNIEnv* env, jobject media_provider_object,
jmethodID mid_on_file_created, const string& path) {
ScopedLocalRef<jstring> j_path(env, env->NewStringUTF(path.c_str()));
env->CallVoidMethod(media_provider_object, mid_on_file_created, j_path.get());
CheckForJniException(env);
return;
}
} // namespace
/*****************************************************************************************/
/******************************* Public API Implementation *******************************/
/*****************************************************************************************/
JavaVM* MediaProviderWrapper::gJavaVm = nullptr;
pthread_key_t MediaProviderWrapper::gJniEnvKey;
void MediaProviderWrapper::OneTimeInit(JavaVM* vm) {
gJavaVm = vm;
CHECK(gJavaVm != nullptr);
pthread_key_create(&MediaProviderWrapper::gJniEnvKey,
MediaProviderWrapper::DetachThreadFunction);
}
MediaProviderWrapper::MediaProviderWrapper(JNIEnv* env, jobject media_provider) {
if (!media_provider) {
LOG(FATAL) << "MediaProvider is null!";
}
media_provider_object_ = reinterpret_cast<jobject>(env->NewGlobalRef(media_provider));
media_provider_class_ = env->FindClass("com/android/providers/media/MediaProvider");
if (!media_provider_class_) {
LOG(FATAL) << "Could not find class MediaProvider";
}
media_provider_class_ = reinterpret_cast<jclass>(env->NewGlobalRef(media_provider_class_));
// Cache methods - Before calling a method, make sure you cache it here
mid_get_redaction_ranges_ = CacheMethod(env, "getRedactionRanges", "(Ljava/lang/String;II)[J",
/*is_static*/ false);
mid_insert_file_ = CacheMethod(env, "insertFileIfNecessary", "(Ljava/lang/String;I)I",
/*is_static*/ false);
mid_delete_file_ = CacheMethod(env, "deleteFile", "(Ljava/lang/String;I)I", /*is_static*/ false);
mid_is_open_allowed_ = CacheMethod(env, "isOpenAllowed", "(Ljava/lang/String;IZ)I",
/*is_static*/ false);
mid_scan_file_ = CacheMethod(env, "scanFile", "(Ljava/lang/String;)V",
/*is_static*/ false);
mid_is_mkdir_or_rmdir_allowed_ = CacheMethod(env, "isDirectoryCreationOrDeletionAllowed",
"(Ljava/lang/String;IZ)I", /*is_static*/ false);
mid_is_opendir_allowed_ = CacheMethod(env, "isOpendirAllowed", "(Ljava/lang/String;IZ)I",
/*is_static*/ false);
mid_get_files_in_dir_ =
CacheMethod(env, "getFilesInDirectory", "(Ljava/lang/String;I)[Ljava/lang/String;",
/*is_static*/ false);
mid_rename_ = CacheMethod(env, "rename", "(Ljava/lang/String;Ljava/lang/String;I)I",
/*is_static*/ false);
mid_is_uid_for_package_ = CacheMethod(env, "isUidForPackage", "(Ljava/lang/String;I)Z",
/*is_static*/ false);
mid_on_file_created_ = CacheMethod(env, "onFileCreated", "(Ljava/lang/String;)V",
/*is_static*/ false);
}
MediaProviderWrapper::~MediaProviderWrapper() {
JNIEnv* env = MaybeAttachCurrentThread();
env->DeleteGlobalRef(media_provider_object_);
env->DeleteGlobalRef(media_provider_class_);
}
std::unique_ptr<RedactionInfo> MediaProviderWrapper::GetRedactionInfo(const string& path, uid_t uid,
pid_t tid) {
if (shouldBypassMediaProvider(uid) || !GetBoolProperty(kPropRedactionEnabled, true)) {
return std::make_unique<RedactionInfo>();
}
// Default value in case JNI thread was being terminated, causes the read to fail.
std::unique_ptr<RedactionInfo> res = nullptr;
JNIEnv* env = MaybeAttachCurrentThread();
auto ri = getRedactionInfoInternal(env, media_provider_object_, mid_get_redaction_ranges_, uid,
tid, path);
res = std::move(ri);
return res;
}
int MediaProviderWrapper::InsertFile(const string& path, uid_t uid) {
if (uid == ROOT_UID) {
return 0;
}
JNIEnv* env = MaybeAttachCurrentThread();
return insertFileInternal(env, media_provider_object_, mid_insert_file_, path, uid);
}
int MediaProviderWrapper::DeleteFile(const string& path, uid_t uid) {
if (uid == ROOT_UID) {
int res = unlink(path.c_str());
return res;
}
JNIEnv* env = MaybeAttachCurrentThread();
return deleteFileInternal(env, media_provider_object_, mid_delete_file_, path, uid);
}
int MediaProviderWrapper::IsOpenAllowed(const string& path, uid_t uid, bool for_write) {
if (shouldBypassMediaProvider(uid)) {
return 0;
}
JNIEnv* env = MaybeAttachCurrentThread();
return isOpenAllowedInternal(env, media_provider_object_, mid_is_open_allowed_, path, uid,
for_write);
}
void MediaProviderWrapper::ScanFile(const string& path) {
JNIEnv* env = MaybeAttachCurrentThread();
scanFileInternal(env, media_provider_object_, mid_scan_file_, path);
}
int MediaProviderWrapper::IsCreatingDirAllowed(const string& path, uid_t uid) {
if (shouldBypassMediaProvider(uid)) {
return 0;
}
JNIEnv* env = MaybeAttachCurrentThread();
return isMkdirOrRmdirAllowedInternal(env, media_provider_object_,
mid_is_mkdir_or_rmdir_allowed_, path, uid,
/*forCreate*/ true);
}
int MediaProviderWrapper::IsDeletingDirAllowed(const string& path, uid_t uid) {
if (shouldBypassMediaProvider(uid)) {
return 0;
}
JNIEnv* env = MaybeAttachCurrentThread();
return isMkdirOrRmdirAllowedInternal(env, media_provider_object_,
mid_is_mkdir_or_rmdir_allowed_, path, uid,
/*forCreate*/ false);
}
std::vector<std::shared_ptr<DirectoryEntry>> MediaProviderWrapper::GetDirectoryEntries(
uid_t uid, const string& path, DIR* dirp) {
// Default value in case JNI thread was being terminated
std::vector<std::shared_ptr<DirectoryEntry>> res;
if (shouldBypassMediaProvider(uid)) {
addDirectoryEntriesFromLowerFs(dirp, /* filter */ nullptr, &res);
return res;
}
JNIEnv* env = MaybeAttachCurrentThread();
res = getFilesInDirectoryInternal(env, media_provider_object_, mid_get_files_in_dir_, uid, path);
const int res_size = res.size();
if (res_size && res[0]->d_name[0] == '/') {
// Path is unknown to MediaProvider, get files and directories from lower file system.
res.resize(0);
addDirectoryEntriesFromLowerFs(dirp, /* filter */ nullptr, &res);
} else if (res_size == 0 || !res[0]->d_name.empty()) {
// add directory names from lower file system.
addDirectoryEntriesFromLowerFs(dirp, /* filter */ &isDirectory, &res);
}
return res;
}
int MediaProviderWrapper::IsOpendirAllowed(const string& path, uid_t uid, bool forWrite) {
if (shouldBypassMediaProvider(uid)) {
return 0;
}
JNIEnv* env = MaybeAttachCurrentThread();
return isOpendirAllowedInternal(env, media_provider_object_, mid_is_opendir_allowed_, path, uid,
forWrite);
}
bool MediaProviderWrapper::IsUidForPackage(const string& pkg, uid_t uid) {
if (shouldBypassMediaProvider(uid)) {
return true;
}
JNIEnv* env = MaybeAttachCurrentThread();
return isUidForPackageInternal(env, media_provider_object_, mid_is_uid_for_package_, pkg, uid);
}
int MediaProviderWrapper::Rename(const string& old_path, const string& new_path, uid_t uid) {
// Rename from SHELL_UID should go through MediaProvider to update database rows, so only bypass
// MediaProvider for ROOT_UID.
if (uid == ROOT_UID) {
int res = rename(old_path.c_str(), new_path.c_str());
if (res != 0) res = -errno;
return res;
}
JNIEnv* env = MaybeAttachCurrentThread();
return renameInternal(env, media_provider_object_, mid_rename_, old_path, new_path, uid);
}
void MediaProviderWrapper::OnFileCreated(const string& path) {
JNIEnv* env = MaybeAttachCurrentThread();
return onFileCreatedInternal(env, media_provider_object_, mid_on_file_created_, path);
}
/*****************************************************************************************/
/******************************** Private member functions *******************************/
/*****************************************************************************************/
/**
* Finds MediaProvider method and adds it to methods map so it can be quickly called later.
*/
jmethodID MediaProviderWrapper::CacheMethod(JNIEnv* env, const char method_name[],
const char signature[], bool is_static) {
jmethodID mid;
string actual_method_name(method_name);
actual_method_name.append("ForFuse");
if (is_static) {
mid = env->GetStaticMethodID(media_provider_class_, actual_method_name.c_str(), signature);
} else {
mid = env->GetMethodID(media_provider_class_, actual_method_name.c_str(), signature);
}
if (!mid) {
// SHOULD NOT HAPPEN!
LOG(FATAL) << "Error caching method: " << method_name << signature;
}
return mid;
}
void MediaProviderWrapper::DetachThreadFunction(void* unused) {
int detach = gJavaVm->DetachCurrentThread();
CHECK_EQ(detach, 0);
}
JNIEnv* MediaProviderWrapper::MaybeAttachCurrentThread() {
// We could use pthread_getspecific here as that's likely quicker but
// that would result in wrong behaviour for threads that don't need to
// be attached (e.g, those that were created in managed code).
JNIEnv* env = nullptr;
if (gJavaVm->GetEnv(reinterpret_cast<void**>(&env), JNI_VERSION_1_4) == JNI_OK) {
return env;
}
// This thread is currently unattached, so it must not have any TLS
// value. Note that we don't really care about the actual value we store
// in TLS -- we only care about the value destructor being called, which
// will happen as long as the key is not null.
CHECK(pthread_getspecific(gJniEnvKey) == nullptr);
CHECK_EQ(gJavaVm->AttachCurrentThread(&env, nullptr), 0);
CHECK(env != nullptr);
pthread_setspecific(gJniEnvKey, env);
return env;
}
} // namespace fuse
} // namespace mediaprovider