| /* |
| * Copyright (C) 2017 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. |
| */ |
| |
| package android.webkit; |
| |
| import android.annotation.NonNull; |
| import android.annotation.Nullable; |
| import android.app.ActivityManagerInternal; |
| import android.content.pm.ApplicationInfo; |
| import android.content.pm.PackageInfo; |
| import android.os.Build; |
| import android.os.Process; |
| import android.os.RemoteException; |
| import android.os.SystemProperties; |
| import android.text.TextUtils; |
| import android.util.Log; |
| |
| import com.android.internal.annotations.VisibleForTesting; |
| import com.android.server.LocalServices; |
| |
| import dalvik.system.VMRuntime; |
| |
| import java.io.File; |
| import java.io.IOException; |
| import java.util.Arrays; |
| import java.util.zip.ZipEntry; |
| import java.util.zip.ZipFile; |
| |
| /** |
| * @hide |
| */ |
| @VisibleForTesting |
| public class WebViewLibraryLoader { |
| private static final String LOGTAG = WebViewLibraryLoader.class.getSimpleName(); |
| |
| private static final String CHROMIUM_WEBVIEW_NATIVE_RELRO_32 = |
| "/data/misc/shared_relro/libwebviewchromium32.relro"; |
| private static final String CHROMIUM_WEBVIEW_NATIVE_RELRO_64 = |
| "/data/misc/shared_relro/libwebviewchromium64.relro"; |
| private static final long CHROMIUM_WEBVIEW_DEFAULT_VMSIZE_BYTES = 100 * 1024 * 1024; |
| |
| private static final boolean DEBUG = false; |
| |
| private static boolean sAddressSpaceReserved = false; |
| |
| /** |
| * Private class for running the actual relro creation in an unprivileged child process. |
| * RelroFileCreator is a static class (without access to the outer class) to avoid accidentally |
| * using any static members from the outer class. Those members will in reality differ between |
| * the child process in which RelroFileCreator operates, and the app process in which the static |
| * members of this class are used. |
| */ |
| private static class RelroFileCreator { |
| // Called in an unprivileged child process to create the relro file. |
| public static void main(String[] args) { |
| boolean result = false; |
| boolean is64Bit = VMRuntime.getRuntime().is64Bit(); |
| try { |
| if (args.length != 1 || args[0] == null) { |
| Log.e(LOGTAG, "Invalid RelroFileCreator args: " + Arrays.toString(args)); |
| return; |
| } |
| Log.v(LOGTAG, "RelroFileCreator (64bit = " + is64Bit + "), lib: " + args[0]); |
| if (!sAddressSpaceReserved) { |
| Log.e(LOGTAG, "can't create relro file; address space not reserved"); |
| return; |
| } |
| result = nativeCreateRelroFile(args[0] /* path */, |
| is64Bit ? CHROMIUM_WEBVIEW_NATIVE_RELRO_64 : |
| CHROMIUM_WEBVIEW_NATIVE_RELRO_32); |
| if (result && DEBUG) Log.v(LOGTAG, "created relro file"); |
| } finally { |
| // We must do our best to always notify the update service, even if something fails. |
| try { |
| WebViewFactory.getUpdateServiceUnchecked().notifyRelroCreationCompleted(); |
| } catch (RemoteException e) { |
| Log.e(LOGTAG, "error notifying update service", e); |
| } |
| |
| if (!result) Log.e(LOGTAG, "failed to create relro file"); |
| |
| // Must explicitly exit or else this process will just sit around after we return. |
| System.exit(0); |
| } |
| } |
| } |
| |
| /** |
| * Create a single relro file by invoking an isolated process that to do the actual work. |
| */ |
| static void createRelroFile(final boolean is64Bit, @NonNull WebViewNativeLibrary nativeLib) { |
| final String abi = |
| is64Bit ? Build.SUPPORTED_64_BIT_ABIS[0] : Build.SUPPORTED_32_BIT_ABIS[0]; |
| |
| // crashHandler is invoked by the ActivityManagerService when the isolated process crashes. |
| Runnable crashHandler = new Runnable() { |
| @Override |
| public void run() { |
| try { |
| Log.e(LOGTAG, "relro file creator for " + abi + " crashed. Proceeding without"); |
| WebViewFactory.getUpdateService().notifyRelroCreationCompleted(); |
| } catch (RemoteException e) { |
| Log.e(LOGTAG, "Cannot reach WebViewUpdateService. " + e.getMessage()); |
| } |
| } |
| }; |
| |
| try { |
| if (nativeLib == null || nativeLib.path == null) { |
| throw new IllegalArgumentException( |
| "Native library paths to the WebView RelRo process must not be null!"); |
| } |
| int pid = LocalServices.getService(ActivityManagerInternal.class).startIsolatedProcess( |
| RelroFileCreator.class.getName(), new String[] { nativeLib.path }, |
| "WebViewLoader-" + abi, abi, Process.SHARED_RELRO_UID, crashHandler); |
| if (pid <= 0) throw new Exception("Failed to start the relro file creator process"); |
| } catch (Throwable t) { |
| // Log and discard errors as we must not crash the system server. |
| Log.e(LOGTAG, "error starting relro file creator for abi " + abi, t); |
| crashHandler.run(); |
| } |
| } |
| |
| /** |
| * Perform preparations needed to allow loading WebView from an application. This method should |
| * be called whenever we change WebView provider. |
| * @return the number of relro processes started. |
| */ |
| static int prepareNativeLibraries(PackageInfo webviewPackageInfo) |
| throws WebViewFactory.MissingWebViewPackageException { |
| WebViewNativeLibrary nativeLib32bit = |
| getWebViewNativeLibrary(webviewPackageInfo, false /* is64bit */); |
| WebViewNativeLibrary nativeLib64bit = |
| getWebViewNativeLibrary(webviewPackageInfo, true /* is64bit */); |
| updateWebViewZygoteVmSize(nativeLib32bit, nativeLib64bit); |
| |
| return createRelros(nativeLib32bit, nativeLib64bit); |
| } |
| |
| /** |
| * @return the number of relro processes started. |
| */ |
| private static int createRelros(@Nullable WebViewNativeLibrary nativeLib32bit, |
| @Nullable WebViewNativeLibrary nativeLib64bit) { |
| if (DEBUG) Log.v(LOGTAG, "creating relro files"); |
| int numRelros = 0; |
| |
| if (Build.SUPPORTED_32_BIT_ABIS.length > 0) { |
| if (nativeLib32bit == null) { |
| Log.e(LOGTAG, "No 32-bit WebView library path, skipping relro creation."); |
| } else { |
| if (DEBUG) Log.v(LOGTAG, "Create 32 bit relro"); |
| createRelroFile(false /* is64Bit */, nativeLib32bit); |
| numRelros++; |
| } |
| } |
| |
| if (Build.SUPPORTED_64_BIT_ABIS.length > 0) { |
| if (nativeLib64bit == null) { |
| Log.e(LOGTAG, "No 64-bit WebView library path, skipping relro creation."); |
| } else { |
| if (DEBUG) Log.v(LOGTAG, "Create 64 bit relro"); |
| createRelroFile(true /* is64Bit */, nativeLib64bit); |
| numRelros++; |
| } |
| } |
| return numRelros; |
| } |
| |
| /** |
| * |
| * @return the native WebView libraries in the new WebView APK. |
| */ |
| private static void updateWebViewZygoteVmSize( |
| @Nullable WebViewNativeLibrary nativeLib32bit, |
| @Nullable WebViewNativeLibrary nativeLib64bit) |
| throws WebViewFactory.MissingWebViewPackageException { |
| // Find the native libraries of the new WebView package, to change the size of the |
| // memory region in the Zygote reserved for the library. |
| long newVmSize = 0L; |
| |
| if (nativeLib32bit != null) newVmSize = Math.max(newVmSize, nativeLib32bit.size); |
| if (nativeLib64bit != null) newVmSize = Math.max(newVmSize, nativeLib64bit.size); |
| |
| if (DEBUG) { |
| Log.v(LOGTAG, "Based on library size, need " + newVmSize |
| + " bytes of address space."); |
| } |
| // The required memory can be larger than the file on disk (due to .bss), and an |
| // upgraded version of the library will likely be larger, so always attempt to |
| // reserve twice as much as we think to allow for the library to grow during this |
| // boot cycle. |
| newVmSize = Math.max(2 * newVmSize, CHROMIUM_WEBVIEW_DEFAULT_VMSIZE_BYTES); |
| Log.d(LOGTAG, "Setting new address space to " + newVmSize); |
| setWebViewZygoteVmSize(newVmSize); |
| } |
| |
| /** |
| * Reserve space for the native library to be loaded into. |
| */ |
| static void reserveAddressSpaceInZygote() { |
| System.loadLibrary("webviewchromium_loader"); |
| long addressSpaceToReserve = |
| SystemProperties.getLong(WebViewFactory.CHROMIUM_WEBVIEW_VMSIZE_SIZE_PROPERTY, |
| CHROMIUM_WEBVIEW_DEFAULT_VMSIZE_BYTES); |
| sAddressSpaceReserved = nativeReserveAddressSpace(addressSpaceToReserve); |
| |
| if (sAddressSpaceReserved) { |
| if (DEBUG) { |
| Log.v(LOGTAG, "address space reserved: " + addressSpaceToReserve + " bytes"); |
| } |
| } else { |
| Log.e(LOGTAG, "reserving " + addressSpaceToReserve + " bytes of address space failed"); |
| } |
| } |
| |
| /** |
| * Load WebView's native library into the current process. |
| * Note: assumes that we have waited for relro creation. |
| * @param clazzLoader class loader used to find the linker namespace to load the library into. |
| * @param packageInfo the package from which WebView is loaded. |
| */ |
| static int loadNativeLibrary(ClassLoader clazzLoader, PackageInfo packageInfo) |
| throws WebViewFactory.MissingWebViewPackageException { |
| if (!sAddressSpaceReserved) { |
| Log.e(LOGTAG, "can't load with relro file; address space not reserved"); |
| return WebViewFactory.LIBLOAD_ADDRESS_SPACE_NOT_RESERVED; |
| } |
| |
| final String libraryFileName = |
| WebViewFactory.getWebViewLibrary(packageInfo.applicationInfo); |
| String relroPath = VMRuntime.getRuntime().is64Bit() ? CHROMIUM_WEBVIEW_NATIVE_RELRO_64 : |
| CHROMIUM_WEBVIEW_NATIVE_RELRO_32; |
| int result = nativeLoadWithRelroFile(libraryFileName, relroPath, clazzLoader); |
| if (result != WebViewFactory.LIBLOAD_SUCCESS) { |
| Log.w(LOGTAG, "failed to load with relro file, proceeding without"); |
| } else if (DEBUG) { |
| Log.v(LOGTAG, "loaded with relro file"); |
| } |
| return result; |
| } |
| |
| /** |
| * Fetch WebView's native library paths from {@param packageInfo}. |
| * @hide |
| */ |
| @Nullable |
| @VisibleForTesting |
| public static WebViewNativeLibrary getWebViewNativeLibrary(PackageInfo packageInfo, |
| boolean is64bit) throws WebViewFactory.MissingWebViewPackageException { |
| ApplicationInfo ai = packageInfo.applicationInfo; |
| final String nativeLibFileName = WebViewFactory.getWebViewLibrary(ai); |
| |
| String dir = getWebViewNativeLibraryDirectory(ai, is64bit /* 64bit */); |
| |
| WebViewNativeLibrary lib = findNativeLibrary(ai, nativeLibFileName, |
| is64bit ? Build.SUPPORTED_64_BIT_ABIS : Build.SUPPORTED_32_BIT_ABIS, dir); |
| |
| if (DEBUG) { |
| Log.v(LOGTAG, String.format("Native %d-bit lib: %s", is64bit ? 64 : 32, lib.path)); |
| } |
| return lib; |
| } |
| |
| /** |
| * @return the directory of the native WebView library with bitness {@param is64bit}. |
| * @hide |
| */ |
| @VisibleForTesting |
| public static String getWebViewNativeLibraryDirectory(ApplicationInfo ai, boolean is64bit) { |
| // Primary arch has the same bitness as the library we are looking for. |
| if (is64bit == VMRuntime.is64BitAbi(ai.primaryCpuAbi)) return ai.nativeLibraryDir; |
| |
| // Secondary arch has the same bitness as the library we are looking for. |
| if (!TextUtils.isEmpty(ai.secondaryCpuAbi)) { |
| return ai.secondaryNativeLibraryDir; |
| } |
| |
| return ""; |
| } |
| |
| /** |
| * @return an object describing a native WebView library given the directory path of that |
| * library, or null if the library couldn't be found. |
| */ |
| @Nullable |
| private static WebViewNativeLibrary findNativeLibrary(ApplicationInfo ai, |
| String nativeLibFileName, String[] abiList, String libDirectory) |
| throws WebViewFactory.MissingWebViewPackageException { |
| if (TextUtils.isEmpty(libDirectory)) return null; |
| String libPath = libDirectory + "/" + nativeLibFileName; |
| File f = new File(libPath); |
| if (f.exists()) { |
| return new WebViewNativeLibrary(libPath, f.length()); |
| } else { |
| return getLoadFromApkPath(ai.sourceDir, abiList, nativeLibFileName); |
| } |
| } |
| |
| /** |
| * @hide |
| */ |
| @VisibleForTesting |
| public static class WebViewNativeLibrary { |
| public final String path; |
| public final long size; |
| |
| WebViewNativeLibrary(String path, long size) { |
| this.path = path; |
| this.size = size; |
| } |
| } |
| |
| private static WebViewNativeLibrary getLoadFromApkPath(String apkPath, |
| String[] abiList, |
| String nativeLibFileName) |
| throws WebViewFactory.MissingWebViewPackageException { |
| // Search the APK for a native library conforming to a listed ABI. |
| try (ZipFile z = new ZipFile(apkPath)) { |
| for (String abi : abiList) { |
| final String entry = "lib/" + abi + "/" + nativeLibFileName; |
| ZipEntry e = z.getEntry(entry); |
| if (e != null && e.getMethod() == ZipEntry.STORED) { |
| // Return a path formatted for dlopen() load from APK. |
| return new WebViewNativeLibrary(apkPath + "!/" + entry, e.getSize()); |
| } |
| } |
| } catch (IOException e) { |
| throw new WebViewFactory.MissingWebViewPackageException(e); |
| } |
| return null; |
| } |
| |
| /** |
| * Sets the size of the memory area in which to store the relro section. |
| */ |
| private static void setWebViewZygoteVmSize(long vmSize) { |
| SystemProperties.set(WebViewFactory.CHROMIUM_WEBVIEW_VMSIZE_SIZE_PROPERTY, |
| Long.toString(vmSize)); |
| } |
| |
| static native boolean nativeReserveAddressSpace(long addressSpaceToReserve); |
| static native boolean nativeCreateRelroFile(String lib, String relro); |
| static native int nativeLoadWithRelroFile(String lib, String relro, ClassLoader clazzLoader); |
| } |