libnativeloader/native_loader.cpp - android-core - Git at Google

 /*
  * Copyright (C) 2015 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 "nativeloader/native_loader.h"
 #include "ScopedUtfChars.h"

 #include <dlfcn.h>
 #ifdef __ANDROID__
 #include "dlext_namespaces.h"
 #include "cutils/properties.h"
 #define LOG_TAG "libnativeloader"
 #include "log/log.h"
 #endif

 #include <algorithm>
 #include <vector>
 #include <string>
 #include <mutex>

 #include "android-base/file.h"
 #include "android-base/macros.h"
 #include "android-base/strings.h"

 namespace android {

 #if defined(__ANDROID__)
 static constexpr const char* kPublicNativeLibrariesSystemConfigPathFromRoot = "/etc/public.libraries.txt";
 static constexpr const char* kPublicNativeLibrariesVendorConfig = "/vendor/etc/public.libraries.txt";

 // (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.
 static constexpr const char* kWhitelistedDirectories = "/data:/mnt/expand";

 static bool is_debuggable() {
   char debuggable[PROP_VALUE_MAX];
   property_get("ro.debuggable", debuggable, "0");
   return std::string(debuggable) == "1";
 }

 class LibraryNamespaces {
  public:
   LibraryNamespaces() : initialized_(false) { }

   android_namespace_t* Create(JNIEnv* env,
                               jobject class_loader,
                               bool is_shared,
                               jstring java_library_path,
                               jstring java_permitted_path) {
     std::string library_path; // empty string by default.

     if (java_library_path != nullptr) {
       ScopedUtfChars library_path_utf_chars(env, java_library_path);
       library_path = library_path_utf_chars.c_str();
     }

     // (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 = kWhitelistedDirectories;

     if (java_permitted_path != nullptr) {
       ScopedUtfChars path(env, java_permitted_path);
       if (path.c_str() != nullptr && path.size() > 0) {
         permitted_path = permitted_path + ":" + path.c_str();
       }
     }

     if (!initialized_ && !InitPublicNamespace(library_path.c_str())) {
       return nullptr;
     }

     android_namespace_t* ns = FindNamespaceByClassLoader(env, class_loader);

     LOG_ALWAYS_FATAL_IF(ns != nullptr,
                         "There is already a namespace associated with this classloader");

     uint64_t namespace_type = ANDROID_NAMESPACE_TYPE_ISOLATED;
     if (is_shared) {
       namespace_type |= ANDROID_NAMESPACE_TYPE_SHARED;
     }

     android_namespace_t* parent_ns = FindParentNamespaceByClassLoader(env, class_loader);

     ns = android_create_namespace("classloader-namespace",
                                   nullptr,
                                   library_path.c_str(),
                                   namespace_type,
                                   permitted_path.c_str(),
                                   parent_ns);

     if (ns != nullptr) {
       namespaces_.push_back(std::make_pair(env->NewWeakGlobalRef(class_loader), ns));
     }

     return ns;
   }

   android_namespace_t* FindNamespaceByClassLoader(JNIEnv* env, jobject class_loader) {
     auto it = std::find_if(namespaces_.begin(), namespaces_.end(),
                 [&](const std::pair<jweak, android_namespace_t*>& value) {
                   return env->IsSameObject(value.first, class_loader);
                 });
     return it != namespaces_.end() ? it->second : nullptr;
   }

   void Initialize() {
     std::vector<std::string> sonames;
     const char* android_root_env = getenv("ANDROID_ROOT");
     std::string root_dir = android_root_env != nullptr ? android_root_env : "/system";
     std::string public_native_libraries_system_config =
             root_dir + kPublicNativeLibrariesSystemConfigPathFromRoot;

     LOG_ALWAYS_FATAL_IF(!ReadConfig(public_native_libraries_system_config, &sonames),
                         "Error reading public native library list from \"%s\": %s",
                         public_native_libraries_system_config.c_str(), strerror(errno));

     // For debuggable platform builds use ANDROID_ADDITIONAL_PUBLIC_LIBRARIES environment
     // variable to add libraries to the list. This is intended for platform tests only.
     if (is_debuggable()) {
       const char* additional_libs = getenv("ANDROID_ADDITIONAL_PUBLIC_LIBRARIES");
       if (additional_libs != nullptr && additional_libs[0] != '\0') {
         std::vector<std::string> additional_libs_vector = base::Split(additional_libs, ":");
         std::copy(additional_libs_vector.begin(),
                   additional_libs_vector.end(),
                   std::back_inserter(sonames));
       }
     }

     // This file is optional, quietly ignore if the file does not exist.
     ReadConfig(kPublicNativeLibrariesVendorConfig, &sonames);

     // android_init_namespaces() expects all the public libraries
     // to be loaded so that they can be found by soname alone.
     //
     // 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
     // For now we rely on CTS test to catch things like this but
     // it should probably be addressed in the future.
     for (const auto& soname : sonames) {
       dlopen(soname.c_str(), RTLD_NOW | RTLD_NODELETE);
     }

     public_libraries_ = base::Join(sonames, ':');
   }

   void Reset() {
     namespaces_.clear();
   }

  private:
   bool ReadConfig(const std::string& configFile, std::vector<std::string>* sonames) {
     // Read list of public native libraries from the config file.
     std::string file_content;
     if(!base::ReadFileToString(configFile, &file_content)) {
       return false;
     }

     std::vector<std::string> lines = base::Split(file_content, "\n");

     for (const auto& line : lines) {
       auto trimmed_line = base::Trim(line);
       if (trimmed_line[0] == '#' || trimmed_line.empty()) {
         continue;
       }

       sonames->push_back(trimmed_line);
     }

     return true;
   }

   bool InitPublicNamespace(const char* library_path) {
     // (http://b/25844435) - Some apps call dlopen from generated code (mono jited
     // code is one example) unknown to linker in which  case linker uses anonymous
     // namespace. The second argument specifies the search path for the anonymous
     // namespace which is the library_path of the classloader.
     initialized_ = android_init_namespaces(public_libraries_.c_str(), library_path);

     return initialized_;
   }

   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);
   }

   android_namespace_t* FindParentNamespaceByClassLoader(JNIEnv* env, jobject class_loader) {
     jobject parent_class_loader = GetParentClassLoader(env, class_loader);

     while (parent_class_loader != nullptr) {
       android_namespace_t* ns = FindNamespaceByClassLoader(env, parent_class_loader);
       if (ns != nullptr) {
         return ns;
       }

       parent_class_loader = GetParentClassLoader(env, parent_class_loader);
     }
     return nullptr;
   }

   bool initialized_;
   std::vector<std::pair<jweak, android_namespace_t*>> namespaces_;
   std::string public_libraries_;


   DISALLOW_COPY_AND_ASSIGN(LibraryNamespaces);
 };

 static std::mutex g_namespaces_mutex;
 static LibraryNamespaces* g_namespaces = new LibraryNamespaces;
 #endif

 void InitializeNativeLoader() {
 #if defined(__ANDROID__)
   std::lock_guard<std::mutex> guard(g_namespaces_mutex);
   g_namespaces->Initialize();
 #endif
 }

 void ResetNativeLoader() {
 #if defined(__ANDROID__)
   std::lock_guard<std::mutex> guard(g_namespaces_mutex);
   g_namespaces->Reset();
 #endif
 }

 jstring CreateClassLoaderNamespace(JNIEnv* env,
                                    int32_t target_sdk_version,
                                    jobject class_loader,
                                    bool is_shared,
                                    jstring library_path,
                                    jstring permitted_path) {
 #if defined(__ANDROID__)
   UNUSED(target_sdk_version);
   std::lock_guard<std::mutex> guard(g_namespaces_mutex);
   android_namespace_t* ns = g_namespaces->Create(env,
                                                  class_loader,
                                                  is_shared,
                                                  library_path,
                                                  permitted_path);
   if (ns == nullptr) {
     return env->NewStringUTF(dlerror());
   }
 #else
   UNUSED(env, target_sdk_version, class_loader, is_shared,
          library_path, permitted_path);
 #endif
   return nullptr;
 }

 void* OpenNativeLibrary(JNIEnv* env,
                         int32_t target_sdk_version,
                         const char* path,
                         jobject class_loader,
                         jstring library_path) {
 #if defined(__ANDROID__)
   UNUSED(target_sdk_version);
   if (class_loader == nullptr) {
     return dlopen(path, RTLD_NOW);
   }

   std::lock_guard<std::mutex> guard(g_namespaces_mutex);
   android_namespace_t* ns = g_namespaces->FindNamespaceByClassLoader(env, class_loader);

   if (ns == nullptr) {
     // This is the case where the classloader was not created by ApplicationLoaders
     // In this case we create an isolated not-shared namespace for it.
     ns = g_namespaces->Create(env, class_loader, false, library_path, nullptr);
     if (ns == nullptr) {
       return nullptr;
     }
   }

   android_dlextinfo extinfo;
   extinfo.flags = ANDROID_DLEXT_USE_NAMESPACE;
   extinfo.library_namespace = ns;

   return android_dlopen_ext(path, RTLD_NOW, &extinfo);
 #else
   UNUSED(env, target_sdk_version, class_loader, library_path);
   return dlopen(path, RTLD_NOW);
 #endif
 }

 bool CloseNativeLibrary(void* handle) {
   return dlclose(handle) == 0;
 }

 #if defined(__ANDROID__)
 android_namespace_t* FindNamespaceByClassLoader(JNIEnv* env, jobject class_loader) {
   std::lock_guard<std::mutex> guard(g_namespaces_mutex);
   return g_namespaces->FindNamespaceByClassLoader(env, class_loader);
 }
 #endif

 }; //  android namespace
	/*
	* Copyright (C) 2015 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 "nativeloader/native_loader.h"
	#include "ScopedUtfChars.h"

	#include <dlfcn.h>
	#ifdef __ANDROID__
	#include "dlext_namespaces.h"
	#include "cutils/properties.h"
	#define LOG_TAG "libnativeloader"
	#include "log/log.h"
	#endif

	#include <algorithm>
	#include <vector>
	#include <string>
	#include <mutex>

	#include "android-base/file.h"
	#include "android-base/macros.h"
	#include "android-base/strings.h"

	namespace android {

	#if defined(__ANDROID__)
	static constexpr const char* kPublicNativeLibrariesSystemConfigPathFromRoot = "/etc/public.libraries.txt";
	static constexpr const char* kPublicNativeLibrariesVendorConfig = "/vendor/etc/public.libraries.txt";

	// (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.
	static constexpr const char* kWhitelistedDirectories = "/data:/mnt/expand";

	static bool is_debuggable() {
	char debuggable[PROP_VALUE_MAX];
	property_get("ro.debuggable", debuggable, "0");
	return std::string(debuggable) == "1";
	}

	class LibraryNamespaces {
	public:
	LibraryNamespaces() : initialized_(false) { }

	android_namespace_t* Create(JNIEnv* env,
	jobject class_loader,
	bool is_shared,
	jstring java_library_path,
	jstring java_permitted_path) {
	std::string library_path; // empty string by default.

	if (java_library_path != nullptr) {
	ScopedUtfChars library_path_utf_chars(env, java_library_path);
	library_path = library_path_utf_chars.c_str();
	}

	// (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 = kWhitelistedDirectories;

	if (java_permitted_path != nullptr) {
	ScopedUtfChars path(env, java_permitted_path);
	if (path.c_str() != nullptr && path.size() > 0) {
	permitted_path = permitted_path + ":" + path.c_str();
	}
	}

	if (!initialized_ && !InitPublicNamespace(library_path.c_str())) {
	return nullptr;
	}

	android_namespace_t* ns = FindNamespaceByClassLoader(env, class_loader);

	LOG_ALWAYS_FATAL_IF(ns != nullptr,
	"There is already a namespace associated with this classloader");

	uint64_t namespace_type = ANDROID_NAMESPACE_TYPE_ISOLATED;
	if (is_shared) {
	namespace_type \|= ANDROID_NAMESPACE_TYPE_SHARED;
	}

	android_namespace_t* parent_ns = FindParentNamespaceByClassLoader(env, class_loader);

	ns = android_create_namespace("classloader-namespace",
	nullptr,
	library_path.c_str(),
	namespace_type,
	permitted_path.c_str(),
	parent_ns);

	if (ns != nullptr) {
	namespaces_.push_back(std::make_pair(env->NewWeakGlobalRef(class_loader), ns));
	}

	return ns;
	}

	android_namespace_t* FindNamespaceByClassLoader(JNIEnv* env, jobject class_loader) {
	auto it = std::find_if(namespaces_.begin(), namespaces_.end(),
	[&](const std::pair<jweak, android_namespace_t*>& value) {
	return env->IsSameObject(value.first, class_loader);
	});
	return it != namespaces_.end() ? it->second : nullptr;
	}

	void Initialize() {
	std::vector<std::string> sonames;
	const char* android_root_env = getenv("ANDROID_ROOT");
	std::string root_dir = android_root_env != nullptr ? android_root_env : "/system";
	std::string public_native_libraries_system_config =
	root_dir + kPublicNativeLibrariesSystemConfigPathFromRoot;

	LOG_ALWAYS_FATAL_IF(!ReadConfig(public_native_libraries_system_config, &sonames),
	"Error reading public native library list from \"%s\": %s",
	public_native_libraries_system_config.c_str(), strerror(errno));

	// For debuggable platform builds use ANDROID_ADDITIONAL_PUBLIC_LIBRARIES environment
	// variable to add libraries to the list. This is intended for platform tests only.
	if (is_debuggable()) {
	const char* additional_libs = getenv("ANDROID_ADDITIONAL_PUBLIC_LIBRARIES");
	if (additional_libs != nullptr && additional_libs[0] != '\0') {
	std::vector<std::string> additional_libs_vector = base::Split(additional_libs, ":");
	std::copy(additional_libs_vector.begin(),
	additional_libs_vector.end(),
	std::back_inserter(sonames));
	}
	}

	// This file is optional, quietly ignore if the file does not exist.
	ReadConfig(kPublicNativeLibrariesVendorConfig, &sonames);

	// android_init_namespaces() expects all the public libraries
	// to be loaded so that they can be found by soname alone.
	//
	// 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
	// For now we rely on CTS test to catch things like this but
	// it should probably be addressed in the future.
	for (const auto& soname : sonames) {
	dlopen(soname.c_str(), RTLD_NOW \| RTLD_NODELETE);
	}

	public_libraries_ = base::Join(sonames, ':');
	}

	void Reset() {
	namespaces_.clear();
	}

	private:
	bool ReadConfig(const std::string& configFile, std::vector<std::string>* sonames) {
	// Read list of public native libraries from the config file.
	std::string file_content;
	if(!base::ReadFileToString(configFile, &file_content)) {
	return false;
	}

	std::vector<std::string> lines = base::Split(file_content, "\n");

	for (const auto& line : lines) {
	auto trimmed_line = base::Trim(line);
	if (trimmed_line[0] == '#' \|\| trimmed_line.empty()) {
	continue;
	}

	sonames->push_back(trimmed_line);
	}

	return true;
	}

	bool InitPublicNamespace(const char* library_path) {
	// (http://b/25844435) - Some apps call dlopen from generated code (mono jited
	// code is one example) unknown to linker in which case linker uses anonymous
	// namespace. The second argument specifies the search path for the anonymous
	// namespace which is the library_path of the classloader.
	initialized_ = android_init_namespaces(public_libraries_.c_str(), library_path);

	return initialized_;
	}

	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);
	}

	android_namespace_t* FindParentNamespaceByClassLoader(JNIEnv* env, jobject class_loader) {
	jobject parent_class_loader = GetParentClassLoader(env, class_loader);

	while (parent_class_loader != nullptr) {
	android_namespace_t* ns = FindNamespaceByClassLoader(env, parent_class_loader);
	if (ns != nullptr) {
	return ns;
	}

	parent_class_loader = GetParentClassLoader(env, parent_class_loader);
	}
	return nullptr;
	}

	bool initialized_;
	std::vector<std::pair<jweak, android_namespace_t*>> namespaces_;
	std::string public_libraries_;


	DISALLOW_COPY_AND_ASSIGN(LibraryNamespaces);
	};

	static std::mutex g_namespaces_mutex;
	static LibraryNamespaces* g_namespaces = new LibraryNamespaces;
	#endif

	void InitializeNativeLoader() {
	#if defined(__ANDROID__)
	std::lock_guard<std::mutex> guard(g_namespaces_mutex);
	g_namespaces->Initialize();
	#endif
	}

	void ResetNativeLoader() {
	#if defined(__ANDROID__)
	std::lock_guard<std::mutex> guard(g_namespaces_mutex);
	g_namespaces->Reset();
	#endif
	}

	jstring CreateClassLoaderNamespace(JNIEnv* env,
	int32_t target_sdk_version,
	jobject class_loader,
	bool is_shared,
	jstring library_path,
	jstring permitted_path) {
	#if defined(__ANDROID__)
	UNUSED(target_sdk_version);
	std::lock_guard<std::mutex> guard(g_namespaces_mutex);
	android_namespace_t* ns = g_namespaces->Create(env,
	class_loader,
	is_shared,
	library_path,
	permitted_path);
	if (ns == nullptr) {
	return env->NewStringUTF(dlerror());
	}
	#else
	UNUSED(env, target_sdk_version, class_loader, is_shared,
	library_path, permitted_path);
	#endif
	return nullptr;
	}

	void* OpenNativeLibrary(JNIEnv* env,
	int32_t target_sdk_version,
	const char* path,
	jobject class_loader,
	jstring library_path) {
	#if defined(__ANDROID__)
	UNUSED(target_sdk_version);
	if (class_loader == nullptr) {
	return dlopen(path, RTLD_NOW);
	}

	std::lock_guard<std::mutex> guard(g_namespaces_mutex);
	android_namespace_t* ns = g_namespaces->FindNamespaceByClassLoader(env, class_loader);

	if (ns == nullptr) {
	// This is the case where the classloader was not created by ApplicationLoaders
	// In this case we create an isolated not-shared namespace for it.
	ns = g_namespaces->Create(env, class_loader, false, library_path, nullptr);
	if (ns == nullptr) {
	return nullptr;
	}
	}

	android_dlextinfo extinfo;
	extinfo.flags = ANDROID_DLEXT_USE_NAMESPACE;
	extinfo.library_namespace = ns;

	return android_dlopen_ext(path, RTLD_NOW, &extinfo);
	#else
	UNUSED(env, target_sdk_version, class_loader, library_path);
	return dlopen(path, RTLD_NOW);
	#endif
	}

	bool CloseNativeLibrary(void* handle) {
	return dlclose(handle) == 0;
	}

	#if defined(__ANDROID__)
	android_namespace_t* FindNamespaceByClassLoader(JNIEnv* env, jobject class_loader) {
	std::lock_guard<std::mutex> guard(g_namespaces_mutex);
	return g_namespaces->FindNamespaceByClassLoader(env, class_loader);
	}
	#endif

	}; // android namespace