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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 specific language governing permissions and
* limitations under the License.
*/
#if defined(ART_TARGET_ANDROID)
#define LOG_TAG "nativeloader"
#include "library_namespaces.h"
#include <dirent.h>
#include <dlfcn.h>
#include <optional>
#include <regex>
#include <string>
#include <vector>
#include "android-base/file.h"
#include "android-base/logging.h"
#include "android-base/macros.h"
#include "android-base/result.h"
#include "android-base/stringprintf.h"
#include "android-base/strings.h"
#include "nativehelper/scoped_utf_chars.h"
#include "nativeloader/dlext_namespaces.h"
#include "public_libraries.h"
#include "utils.h"
namespace android::nativeloader {
namespace {
constexpr const char* kApexPath = "/apex/";
// clns-XX is a linker namespace that is created for normal apps installed in
// the data partition. To be specific, it is created for the app classloader.
// When System.load() is called from a Java class that is loaded from the
// classloader, the clns namespace associated with that classloader is selected
// for dlopen. The namespace is configured so that its search path is set to the
// app-local JNI directory and it is linked to the system namespace with the
// names of libs listed in the public.libraries.txt and other public libraries.
// This way an app can only load its own JNI libraries along with the public
// libs.
constexpr const char* kClassloaderNamespaceName = "clns";
// Same thing for unbundled APKs in the vendor partition.
constexpr const char* kVendorClassloaderNamespaceName = "vendor-clns";
// Same thing for unbundled APKs in the product partition.
constexpr const char* kProductClassloaderNamespaceName = "product-clns";
// If the namespace is shared then add this suffix to help identify it in debug
// messages. A shared namespace (cf. ANDROID_NAMESPACE_TYPE_SHARED) has
// inherited all the libraries of the parent classloader namespace, or the
// system namespace for the main app classloader. It is used to give full access
// to the platform libraries for apps bundled in the system image, including
// their later updates installed in /data.
constexpr const char* kSharedNamespaceSuffix = "-shared";
// (http://b/27588281) This is a workaround for apps using custom classloaders and calling
// System.load() with an absolute path which is outside of the classloader library search path.
// This list includes all directories app is allowed to access this way.
constexpr const char* kAlwaysPermittedDirectories = "/data:/mnt/expand";
constexpr const char* kVendorLibPath = "/vendor/" LIB;
// TODO(mast): It's unlikely that both paths are necessary for kProductLibPath
// below, because they can't be two separate directories - either one has to be
// a symlink to the other.
constexpr const char* kProductLibPath = "/product/" LIB ":/system/product/" LIB;
const std::regex kVendorPathRegex("(^|:)(/system)?/vendor/");
const std::regex kProductPathRegex("(^|:)(/system)?/product/");
jobject GetParentClassLoader(JNIEnv* env, jobject class_loader) {
jclass class_loader_class = env->FindClass("java/lang/ClassLoader");
jmethodID get_parent =
env->GetMethodID(class_loader_class, "getParent", "()Ljava/lang/ClassLoader;");
return env->CallObjectMethod(class_loader, get_parent);
}
} // namespace
ApiDomain GetApiDomainFromPath(const std::string& path) {
ApiDomain api_domain = API_DOMAIN_DEFAULT;
if (std::regex_search(path, kVendorPathRegex)) {
api_domain = API_DOMAIN_VENDOR;
}
if (is_product_treblelized() && std::regex_search(path, kProductPathRegex)) {
LOG_ALWAYS_FATAL_IF(api_domain == API_DOMAIN_VENDOR,
"Path matches both vendor and product partitions: %s",
path.c_str());
api_domain = API_DOMAIN_PRODUCT;
}
return api_domain;
}
void LibraryNamespaces::Initialize() {
// Once public namespace is initialized there is no
// point in running this code - it will have no effect
// on the current list of public libraries.
if (initialized_) {
return;
}
// Load the preloadable public libraries. Since libnativeloader is in the
// com_android_art namespace, use OpenSystemLibrary rather than dlopen to
// ensure the libraries are loaded in the system namespace.
//
// TODO(dimitry): this is a bit misleading since we do not know
// if the vendor public library is going to be opened from /vendor/lib
// we might as well end up loading them from /system/lib or /product/lib
// For now we rely on CTS test to catch things like this but
// it should probably be addressed in the future.
for (const std::string& soname : android::base::Split(preloadable_public_libraries(), ":")) {
void* handle = OpenSystemLibrary(soname.c_str(), RTLD_NOW | RTLD_NODELETE);
LOG_ALWAYS_FATAL_IF(handle == nullptr,
"Error preloading public library %s: %s", soname.c_str(), dlerror());
}
}
// "ALL" is a magic name that allows all public libraries even when the
// target SDK is > 30. Currently this is used for (Java) shared libraries
// which don't use <uses-native-library>
// TODO(b/142191088) remove this hack
static constexpr const char LIBRARY_ALL[] = "ALL";
// Returns the colon-separated list of library names by filtering uses_libraries from
// public_libraries. The returned names will actually be available to the app. If the app is pre-S
// (<= 30), the filtering is not done; the entire public_libraries are provided.
static const std::string filter_public_libraries(
uint32_t target_sdk_version, const std::vector<std::string>& uses_libraries,
const std::string& public_libraries) {
// Apps targeting Android 11 or earlier gets all public libraries
if (target_sdk_version <= 30) {
return public_libraries;
}
if (std::find(uses_libraries.begin(), uses_libraries.end(), LIBRARY_ALL) !=
uses_libraries.end()) {
return public_libraries;
}
std::vector<std::string> filtered;
std::vector<std::string> orig = android::base::Split(public_libraries, ":");
for (const std::string& lib : uses_libraries) {
if (std::find(orig.begin(), orig.end(), lib) != orig.end()) {
filtered.emplace_back(lib);
}
}
return android::base::Join(filtered, ":");
}
Result<NativeLoaderNamespace*> LibraryNamespaces::Create(JNIEnv* env,
uint32_t target_sdk_version,
jobject class_loader,
ApiDomain api_domain,
bool is_shared,
const std::string& dex_path,
jstring library_path_j,
jstring permitted_path_j,
jstring uses_library_list_j) {
std::string library_path; // empty string by default.
if (library_path_j != nullptr) {
ScopedUtfChars library_path_utf_chars(env, library_path_j);
library_path = library_path_utf_chars.c_str();
}
std::vector<std::string> uses_libraries;
if (uses_library_list_j != nullptr) {
ScopedUtfChars names(env, uses_library_list_j);
uses_libraries = android::base::Split(names.c_str(), ":");
} else {
// uses_library_list_j could be nullptr when System.loadLibrary is called
// from a custom classloader. In that case, we don't know the list of public
// libraries because we don't know which apk the classloader is for. Only
// choices we can have are 1) allowing all public libs (as before), or 2)
// not allowing all but NDK libs. Here we take #1 because #2 would surprise
// developers unnecessarily.
// TODO(b/142191088) finalize the policy here. We could either 1) allow all
// public libs, 2) disallow any lib, or 3) use the libs that were granted to
// the first (i.e. app main) classloader.
uses_libraries.emplace_back(LIBRARY_ALL);
}
// (http://b/27588281) This is a workaround for apps using custom
// classloaders and calling System.load() with an absolute path which
// is outside of the classloader library search path.
//
// This part effectively allows such a classloader to access anything
// under /data and /mnt/expand
std::string permitted_path = kAlwaysPermittedDirectories;
if (permitted_path_j != nullptr) {
ScopedUtfChars path(env, permitted_path_j);
if (path.c_str() != nullptr && path.size() > 0) {
permitted_path = permitted_path + ":" + path.c_str();
}
}
LOG_ALWAYS_FATAL_IF(FindNamespaceByClassLoader(env, class_loader) != nullptr,
"There is already a namespace associated with this classloader");
std::string system_exposed_libraries = default_public_libraries();
std::string namespace_name = kClassloaderNamespaceName;
ApiDomain unbundled_app_domain = API_DOMAIN_DEFAULT;
const char* api_domain_msg = "other apk"; // Only for debug logging.
if (!is_shared) {
if (api_domain == API_DOMAIN_VENDOR) {
unbundled_app_domain = API_DOMAIN_VENDOR;
api_domain_msg = "unbundled vendor apk";
// For vendor apks, give access to the vendor libs even though they are
// treated as unbundled; the libs and apks are still bundled together in the
// vendor partition.
library_path = library_path + ':' + kVendorLibPath;
permitted_path = permitted_path + ':' + kVendorLibPath;
// Also give access to LLNDK libraries since they are available to vendor.
system_exposed_libraries = system_exposed_libraries + ':' + llndk_libraries_vendor();
// Different name is useful for debugging
namespace_name = kVendorClassloaderNamespaceName;
} else if (api_domain == API_DOMAIN_PRODUCT) {
unbundled_app_domain = API_DOMAIN_PRODUCT;
api_domain_msg = "unbundled product apk";
// Like for vendor apks, give access to the product libs since they are
// bundled together in the same partition.
library_path = library_path + ':' + kProductLibPath;
permitted_path = permitted_path + ':' + kProductLibPath;
// Also give access to LLNDK libraries since they are available to product.
system_exposed_libraries = system_exposed_libraries + ':' + llndk_libraries_product();
// Different name is useful for debugging
namespace_name = kProductClassloaderNamespaceName;
}
}
if (is_shared) {
// Show in the name that the namespace was created as shared, for debugging
// purposes.
namespace_name = namespace_name + kSharedNamespaceSuffix;
}
// Append a unique number to the namespace name, to tell them apart when
// debugging linker issues, e.g. with debug.ld.all set to "dlopen,dlerror".
static int clns_count = 0;
namespace_name = android::base::StringPrintf("%s-%d", namespace_name.c_str(), ++clns_count);
ALOGD(
"Configuring %s for %s %s. target_sdk_version=%u, uses_libraries=%s, library_path=%s, "
"permitted_path=%s",
namespace_name.c_str(),
api_domain_msg,
dex_path.c_str(),
static_cast<unsigned>(target_sdk_version),
android::base::Join(uses_libraries, ':').c_str(),
library_path.c_str(),
permitted_path.c_str());
if (unbundled_app_domain != API_DOMAIN_VENDOR) {
// Extended public libraries are NOT available to unbundled vendor apks, but
// they are to other apps, including those in system, system_ext, and
// product partitions. The reason is that when GSI is used, the system
// partition may get replaced, and then vendor apps may fail. It's fine for
// product apps, because that partition isn't mounted in GSI tests.
const std::string libs =
filter_public_libraries(target_sdk_version, uses_libraries, extended_public_libraries());
if (!libs.empty()) {
ALOGD("Extending system_exposed_libraries: %s", libs.c_str());
system_exposed_libraries = system_exposed_libraries + ':' + libs;
}
}
// Create the app namespace
NativeLoaderNamespace* parent_ns = FindParentNamespaceByClassLoader(env, class_loader);
// Heuristic: the first classloader with non-empty library_path is assumed to
// be the main classloader for app
// TODO(b/139178525) remove this heuristic by determining this in LoadedApk (or its
// friends) and then passing it down to here.
bool is_main_classloader = app_main_namespace_ == nullptr && !library_path.empty();
// Policy: the namespace for the main classloader is also used as the
// anonymous namespace.
bool also_used_as_anonymous = is_main_classloader;
// Note: this function is executed with g_namespaces_mutex held, thus no
// racing here.
Result<NativeLoaderNamespace> app_ns =
NativeLoaderNamespace::Create(namespace_name,
library_path,
permitted_path,
parent_ns,
is_shared,
target_sdk_version < 24 /* is_exempt_list_enabled */,
also_used_as_anonymous);
if (!app_ns.ok()) {
return app_ns.error();
}
// ... and link to other namespaces to allow access to some public libraries
bool is_bridged = app_ns->IsBridged();
Result<NativeLoaderNamespace> system_ns = NativeLoaderNamespace::GetSystemNamespace(is_bridged);
if (!system_ns.ok()) {
return system_ns.error();
}
Result<void> linked = app_ns->Link(&system_ns.value(), system_exposed_libraries);
if (!linked.ok()) {
return linked.error();
}
for (const auto&[apex_ns_name, public_libs] : apex_public_libraries()) {
Result<NativeLoaderNamespace> ns =
NativeLoaderNamespace::GetExportedNamespace(apex_ns_name, is_bridged);
// Even if APEX namespace is visible, it may not be available to bridged.
if (ns.ok()) {
linked = app_ns->Link(&ns.value(), public_libs);
if (!linked.ok()) {
return linked.error();
}
}
}
// Give access to VNDK-SP libraries from the 'vndk' namespace for unbundled vendor apps.
if (unbundled_app_domain == API_DOMAIN_VENDOR && !vndksp_libraries_vendor().empty()) {
Result<NativeLoaderNamespace> vndk_ns =
NativeLoaderNamespace::GetExportedNamespace(kVndkNamespaceName, is_bridged);
if (vndk_ns.ok()) {
linked = app_ns->Link(&vndk_ns.value(), vndksp_libraries_vendor());
if (!linked.ok()) {
return linked.error();
}
}
}
// Give access to VNDK-SP libraries from the 'vndk_product' namespace for unbundled product apps.
if (unbundled_app_domain == API_DOMAIN_PRODUCT && !vndksp_libraries_product().empty()) {
Result<NativeLoaderNamespace> vndk_ns =
NativeLoaderNamespace::GetExportedNamespace(kVndkProductNamespaceName, is_bridged);
if (vndk_ns.ok()) {
linked = app_ns->Link(&vndk_ns.value(), vndksp_libraries_product());
if (!linked.ok()) {
return linked.error();
}
}
}
for (const std::string& each_jar_path : android::base::Split(dex_path, ":")) {
std::optional<std::string> apex_ns_name = FindApexNamespaceName(each_jar_path);
if (apex_ns_name.has_value()) {
const std::string& jni_libs = apex_jni_libraries(apex_ns_name.value());
if (jni_libs != "") {
Result<NativeLoaderNamespace> apex_ns =
NativeLoaderNamespace::GetExportedNamespace(apex_ns_name.value(), is_bridged);
if (apex_ns.ok()) {
linked = app_ns->Link(&apex_ns.value(), jni_libs);
if (!linked.ok()) {
return linked.error();
}
}
}
}
}
const std::string vendor_libs =
filter_public_libraries(target_sdk_version, uses_libraries, vendor_public_libraries());
if (!vendor_libs.empty()) {
Result<NativeLoaderNamespace> vendor_ns =
NativeLoaderNamespace::GetExportedNamespace(kVendorNamespaceName, is_bridged);
// when vendor_ns is not configured, link to the system namespace
Result<NativeLoaderNamespace> target_ns = vendor_ns.ok() ? vendor_ns : system_ns;
if (target_ns.ok()) {
linked = app_ns->Link(&target_ns.value(), vendor_libs);
if (!linked.ok()) {
return linked.error();
}
}
}
const std::string product_libs =
filter_public_libraries(target_sdk_version, uses_libraries, product_public_libraries());
if (!product_libs.empty()) {
Result<NativeLoaderNamespace> target_ns = system_ns;
if (is_product_treblelized()) {
target_ns = NativeLoaderNamespace::GetExportedNamespace(kProductNamespaceName, is_bridged);
}
if (target_ns.ok()) {
linked = app_ns->Link(&target_ns.value(), product_libs);
if (!linked.ok()) {
return linked.error();
}
} else {
// The linkerconfig must have a problem on defining the product namespace in the system
// section. Skip linking product namespace. This will not affect most of the apps. Only the
// apps that requires the product public libraries will fail.
ALOGW("Namespace for product libs not found: %s", target_ns.error().message().c_str());
}
}
std::pair<jweak, NativeLoaderNamespace>& emplaced =
namespaces_.emplace_back(std::make_pair(env->NewWeakGlobalRef(class_loader), *app_ns));
if (is_main_classloader) {
app_main_namespace_ = &emplaced.second;
}
return &emplaced.second;
}
NativeLoaderNamespace* LibraryNamespaces::FindNamespaceByClassLoader(JNIEnv* env,
jobject class_loader) {
auto it = std::find_if(namespaces_.begin(), namespaces_.end(),
[&](const std::pair<jweak, NativeLoaderNamespace>& value) {
return env->IsSameObject(value.first, class_loader);
});
if (it != namespaces_.end()) {
return &it->second;
}
return nullptr;
}
NativeLoaderNamespace* LibraryNamespaces::FindParentNamespaceByClassLoader(JNIEnv* env,
jobject class_loader) {
jobject parent_class_loader = GetParentClassLoader(env, class_loader);
while (parent_class_loader != nullptr) {
NativeLoaderNamespace* ns;
if ((ns = FindNamespaceByClassLoader(env, parent_class_loader)) != nullptr) {
return ns;
}
parent_class_loader = GetParentClassLoader(env, parent_class_loader);
}
return nullptr;
}
std::optional<std::string> FindApexNamespaceName(const std::string& location) {
// Lots of implicit assumptions here: we expect `location` to be of the form:
// /apex/modulename/...
//
// And we extract from it 'modulename', and then apply mangling rule to get namespace name for it.
if (android::base::StartsWith(location, kApexPath)) {
size_t start_index = strlen(kApexPath);
size_t slash_index = location.find_first_of('/', start_index);
LOG_ALWAYS_FATAL_IF((slash_index == std::string::npos),
"Error finding namespace of apex: no slash in path %s", location.c_str());
std::string name = location.substr(start_index, slash_index - start_index);
std::replace(name.begin(), name.end(), '.', '_');
return name;
}
return std::nullopt;
}
} // namespace android::nativeloader
#endif // defined(ART_TARGET_ANDROID)