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author | Torne (Richard Coles) <torne@google.com> | 2014-05-16 14:18:00 +0100 |
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committer | Torne (Richard Coles) <torne@google.com> | 2014-06-27 16:13:30 +0100 |
commit | bf558c3c576bc709b38886e986010df3b61291bd (patch) | |
tree | 2086cadc817f3f1a8b439f6b452a7732fcf4c02a /chromium/loader | |
parent | 47f61d2406473b823814c457633d1d21a9af7efb (diff) | |
download | webview-bf558c3c576bc709b38886e986010df3b61291bd.tar.gz |
Add loader library to handle relro sharing.
Create a small native library that just contains the JNI code for
WebViewFactory, to enable loading of the full WebView native library
using android_dlopen_ext.
Bug: 13005501
Change-Id: I9608431a66868124f1c1ac618b2c24e2f2608631
Diffstat (limited to 'chromium/loader')
-rw-r--r-- | chromium/loader/loader.cpp | 250 |
1 files changed, 250 insertions, 0 deletions
diff --git a/chromium/loader/loader.cpp b/chromium/loader/loader.cpp new file mode 100644 index 0000000..a5e4e7f --- /dev/null +++ b/chromium/loader/loader.cpp @@ -0,0 +1,250 @@ +/* + * Copyright (C) 2014 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. + */ + +// Uncomment for verbose logging. +// #define LOG_NDEBUG 0 +#define LOG_TAG "webviewchromiumloader" + +#include <dlfcn.h> +#include <errno.h> +#include <fcntl.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <sys/mman.h> +#include <sys/stat.h> +#include <sys/types.h> + +#include <jni.h> +#include <android/dlext.h> +#include <utils/Log.h> + +#define NELEM(x) ((int) (sizeof(x) / sizeof((x)[0]))) + +namespace android { +namespace { + +void* gReservedAddress = NULL; +size_t gReservedSize = 0; + +jboolean DoReserveAddressSpace(const char* lib) { + size_t vsize = 0; + + // First check for a file which explicitly specifies the virtual size needed. + // The file has a .so suffix so that the package manager will extract it + // alongside the real library. + static const char vsize_suffix[] = ".vsize.so"; + char vsize_name[strlen(lib) + sizeof(vsize_suffix)]; + strlcpy(vsize_name, lib, sizeof(vsize_name)); + strlcat(vsize_name, vsize_suffix, sizeof(vsize_name)); + FILE* vsize_file = fopen(vsize_name, "r"); + if (vsize_file != NULL) { + fscanf(vsize_file, "%zd", &vsize); + fclose(vsize_file); + } + + // If the file didn't exist or was unparseable, just stat() the library to see + // how big it is. + if (vsize == 0) { + struct stat libstat; + if (stat(lib, &libstat) != 0) { + ALOGE("Failed to stat %s: %s", lib, strerror(errno)); + return JNI_FALSE; + } + // The required memory can be larger than the file on disk due to the .bss + // section, and an upgraded version of the library installed later may also + // be larger, so we need to allocate more than the size of the file. + vsize = libstat.st_size * 2; + } + + void* addr = mmap(NULL, vsize, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + if (addr == MAP_FAILED) { + ALOGE("Failed to reserve %zd bytes of address space for future load of %s: %s", + vsize, lib, strerror(errno)); + return JNI_FALSE; + } + gReservedAddress = addr; + gReservedSize = vsize; + ALOGV("Reserved %zd bytes at %p", vsize, addr); + return JNI_TRUE; +} + +jboolean DoCreateRelroFile(const char* lib, const char* relro) { + // Try to unlink the old file, since if this is being called, the old one is + // obsolete. + if (unlink(relro) != 0 && errno != ENOENT) { + // If something went wrong other than the file not existing, log a warning + // but continue anyway in the hope that we can successfully overwrite the + // existing file with rename() later. + ALOGW("Failed to unlink old file %s: %s", relro, strerror(errno)); + } + static const char tmpsuffix[] = ".XXXXXX"; + char relro_tmp[strlen(relro) + sizeof(tmpsuffix)]; + strlcpy(relro_tmp, relro, sizeof(relro_tmp)); + strlcat(relro_tmp, tmpsuffix, sizeof(relro_tmp)); + int tmp_fd = TEMP_FAILURE_RETRY(mkstemp(relro_tmp)); + if (tmp_fd == -1) { + ALOGE("Failed to create temporary file %s: %s", relro_tmp, strerror(errno)); + return JNI_FALSE; + } + android_dlextinfo extinfo; + extinfo.flags = ANDROID_DLEXT_RESERVED_ADDRESS | ANDROID_DLEXT_WRITE_RELRO; + extinfo.reserved_addr = gReservedAddress; + extinfo.reserved_size = gReservedSize; + extinfo.relro_fd = tmp_fd; + void* handle = android_dlopen_ext(lib, RTLD_NOW, &extinfo); + int close_result = close(tmp_fd); + if (handle == NULL) { + ALOGE("Failed to load library %s: %s", lib, dlerror()); + unlink(relro_tmp); + return JNI_FALSE; + } + if (close_result != 0 || + chmod(relro_tmp, S_IRUSR | S_IRGRP | S_IROTH) != 0 || + rename(relro_tmp, relro) != 0) { + ALOGE("Failed to update relro file %s: %s", relro, strerror(errno)); + unlink(relro_tmp); + return JNI_FALSE; + } + ALOGV("Created relro file %s for library %s", relro, lib); + return JNI_TRUE; +} + +jboolean DoLoadWithRelroFile(const char* lib, const char* relro) { + int relro_fd = TEMP_FAILURE_RETRY(open(relro, O_RDONLY)); + if (relro_fd == -1) { + ALOGE("Failed to open relro file %s: %s", relro, strerror(errno)); + return JNI_FALSE; + } + android_dlextinfo extinfo; + extinfo.flags = ANDROID_DLEXT_RESERVED_ADDRESS | ANDROID_DLEXT_USE_RELRO; + extinfo.reserved_addr = gReservedAddress; + extinfo.reserved_size = gReservedSize; + extinfo.relro_fd = relro_fd; + void* handle = android_dlopen_ext(lib, RTLD_NOW, &extinfo); + close(relro_fd); + if (handle == NULL) { + ALOGE("Failed to load library %s: %s", lib, dlerror()); + return JNI_FALSE; + } + ALOGV("Loaded library %s with relro file %s", lib, relro); + return JNI_TRUE; +} + +/******************************************************************************/ +/* JNI wrappers - handle string lifetimes and 32/64 ABI choice */ +/******************************************************************************/ + +jboolean ReserveAddressSpace(JNIEnv* env, jclass, jstring lib32, jstring lib64) { +#ifdef __LP64__ + jstring lib = lib64; + (void)lib32; +#else + jstring lib = lib32; + (void)lib64; +#endif + jboolean ret = JNI_FALSE; + const char* lib_utf8 = env->GetStringUTFChars(lib, NULL); + if (lib_utf8 != NULL) { + ret = DoReserveAddressSpace(lib_utf8); + env->ReleaseStringUTFChars(lib, lib_utf8); + } + return ret; +} + +jboolean CreateRelroFile(JNIEnv* env, jclass, jstring lib32, jstring lib64, + jstring relro32, jstring relro64) { +#ifdef __LP64__ + jstring lib = lib64; + jstring relro = relro64; + (void)lib32; (void)relro32; +#else + jstring lib = lib32; + jstring relro = relro32; + (void)lib64; (void)relro64; +#endif + jboolean ret = JNI_FALSE; + const char* lib_utf8 = env->GetStringUTFChars(lib, NULL); + if (lib_utf8 != NULL) { + const char* relro_utf8 = env->GetStringUTFChars(relro, NULL); + if (relro_utf8 != NULL) { + ret = DoCreateRelroFile(lib_utf8, relro_utf8); + env->ReleaseStringUTFChars(relro, relro_utf8); + } + env->ReleaseStringUTFChars(lib, lib_utf8); + } + return ret; +} + +jboolean LoadWithRelroFile(JNIEnv* env, jclass, jstring lib32, jstring lib64, + jstring relro32, jstring relro64) { +#ifdef __LP64__ + jstring lib = lib64; + jstring relro = relro64; + (void)lib32; (void)relro32; +#else + jstring lib = lib32; + jstring relro = relro32; + (void)lib64; (void)relro64; +#endif + jboolean ret = JNI_FALSE; + const char* lib_utf8 = env->GetStringUTFChars(lib, NULL); + if (lib_utf8 != NULL) { + const char* relro_utf8 = env->GetStringUTFChars(relro, NULL); + if (relro_utf8 != NULL) { + ret = DoLoadWithRelroFile(lib_utf8, relro_utf8); + env->ReleaseStringUTFChars(relro, relro_utf8); + } + env->ReleaseStringUTFChars(lib, lib_utf8); + } + return ret; +} + +const char kClassName[] = "android/webkit/WebViewFactory"; +const JNINativeMethod kJniMethods[] = { + { "nativeReserveAddressSpace", "(Ljava/lang/String;Ljava/lang/String;)Z", + reinterpret_cast<void*>(ReserveAddressSpace) }, + { "nativeCreateRelroFile", + "(Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;)Z", + reinterpret_cast<void*>(CreateRelroFile) }, + { "nativeLoadWithRelroFile", + "(Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;)Z", + reinterpret_cast<void*>(LoadWithRelroFile) }, +}; + +} // namespace + +void RegisterWebViewFactory(JNIEnv* env) { + // If either of these fail, it will set an exception that will be thrown on + // return, so no need to handle errors here. + jclass clazz = env->FindClass(kClassName); + if (clazz) { + env->RegisterNatives(clazz, kJniMethods, NELEM(kJniMethods)); + } +} + +} // namespace android + +JNIEXPORT jint JNI_OnLoad(JavaVM* vm, void*) { + JNIEnv* env = NULL; + if (vm->GetEnv(reinterpret_cast<void**>(&env), JNI_VERSION_1_6) != JNI_OK) { + ALOGE("GetEnv failed"); + return JNI_ERR; + } + android::RegisterWebViewFactory(env); + return JNI_VERSION_1_6; +} |