Simplify WebView RELRO creation and handle more cases.

Instead of having the system server search for the absolute path to the
WebView's native .so file, simply pass the package name and library
filename to the RELRO creation process. The RELRO creation process can
then request a classloader that corresponds to that package, and use
that classloader to let the system search for the library itself using
the standard platform library search path logic.

This significantly simplifies the WebView code, but more importantly
enables the library to be found even if it's not actually present in the
main WebView APK and is instead stored in a shared library APK: our
previous code was never updated to handle this new case when the
platform introduced it.

As a side effect of no longer searching for the library, we also no
longer discover the size of the library, and thus cannot use the size to
calculate the amount of address space to reserve. This has been replaced
with a fixed size: 100MB for 32-bit processes (the previous default size
for when the size had not yet been calculated), and 1GB for 64-bit
processes. We do not anticipate WebView ever needing more than 100MB of
virtual address space for its native library on 32-bit platforms; it
currently uses about 44MB.

The unit tests covering the complex library searching logic have been
removed, as the functionality they are testing no longer exists.

Bug: 110790153
Test: WebView-related CTS and GTS tests
Change-Id: Icc7bcd0a2b33f4dbf26d0d663e098c9e207281a5

1 files changed, 43 insertions, 175 deletions

diff --git a/core/java/android/webkit/WebViewLibraryLoader.java b/core/java/android/webkit/WebViewLibraryLoader.java
index cabba06bdff5..5a6aebaaad51 100644
--- a/core/java/android/webkit/WebViewLibraryLoader.java
+++ b/core/java/android/webkit/WebViewLibraryLoader.java
@@ -17,15 +17,14 @@
 package android.webkit;
 
 import android.annotation.NonNull;
-import android.annotation.Nullable;
 import android.app.ActivityManagerInternal;
-import android.content.pm.ApplicationInfo;
+import android.app.ActivityThread;
+import android.app.LoadedApk;
+import android.content.Context;
 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;
@@ -33,11 +32,7 @@ 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
@@ -50,7 +45,6 @@ public class WebViewLibraryLoader {
             "/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;
 
@@ -69,18 +63,26 @@ public class WebViewLibraryLoader {
             boolean result = false;
             boolean is64Bit = VMRuntime.getRuntime().is64Bit();
             try {
-                if (args.length != 1 || args[0] == null) {
+                if (args.length != 2 || args[0] == null || args[1] == null) {
                     Log.e(LOGTAG, "Invalid RelroFileCreator args: " + Arrays.toString(args));
                     return;
                 }
-                Log.v(LOGTAG, "RelroFileCreator (64bit = " + is64Bit + "), lib: " + args[0]);
+                String packageName = args[0];
+                String libraryFileName = args[1];
+                Log.v(LOGTAG, "RelroFileCreator (64bit = " + is64Bit + "), package: "
+                        + packageName + " library: " + libraryFileName);
                 if (!sAddressSpaceReserved) {
                     Log.e(LOGTAG, "can't create relro file; address space not reserved");
                     return;
                 }
-                result = nativeCreateRelroFile(args[0] /* path */,
+                LoadedApk apk = ActivityThread.currentActivityThread().getPackageInfo(
+                        packageName,
+                        null,
+                        Context.CONTEXT_INCLUDE_CODE | Context.CONTEXT_IGNORE_SECURITY);
+                result = nativeCreateRelroFile(libraryFileName,
                                                is64Bit ? CHROMIUM_WEBVIEW_NATIVE_RELRO_64 :
-                                                         CHROMIUM_WEBVIEW_NATIVE_RELRO_32);
+                                                         CHROMIUM_WEBVIEW_NATIVE_RELRO_32,
+                                               apk.getClassLoader());
                 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.
@@ -101,7 +103,8 @@ public class WebViewLibraryLoader {
     /**
      * 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) {
+    static void createRelroFile(final boolean is64Bit, @NonNull String packageName,
+            @NonNull String libraryFileName) {
         final String abi =
                 is64Bit ? Build.SUPPORTED_64_BIT_ABIS[0] : Build.SUPPORTED_32_BIT_ABIS[0];
 
@@ -119,13 +122,10 @@ public class WebViewLibraryLoader {
         };
 
         try {
-            if (nativeLib == null || nativeLib.path == null) {
-                throw new IllegalArgumentException(
-                        "Native library paths to the WebView RelRo process must not be null!");
-            }
             boolean success = LocalServices.getService(ActivityManagerInternal.class)
                     .startIsolatedProcess(
-                            RelroFileCreator.class.getName(), new String[] { nativeLib.path },
+                            RelroFileCreator.class.getName(),
+                            new String[] { packageName, libraryFileName },
                             "WebViewLoader-" + abi, abi, Process.SHARED_RELRO_UID, crashHandler);
             if (!success) throw new Exception("Failed to start the relro file creator process");
         } catch (Throwable t) {
@@ -140,83 +140,50 @@ public class WebViewLibraryLoader {
      * 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);
+    static int prepareNativeLibraries(@NonNull PackageInfo webViewPackageInfo) {
+        // TODO(torne): new way of calculating VM size
+        // updateWebViewZygoteVmSize(nativeLib32bit, nativeLib64bit);
+        String libraryFileName = WebViewFactory.getWebViewLibrary(
+                webViewPackageInfo.applicationInfo);
+        if (libraryFileName == null) {
+            // Can't do anything with no filename, don't spawn any processes.
+            return 0;
+        }
+        return createRelros(webViewPackageInfo.packageName, libraryFileName);
     }
 
     /**
      * @return the number of relro processes started.
      */
-    private static int createRelros(@Nullable WebViewNativeLibrary nativeLib32bit,
-            @Nullable WebViewNativeLibrary nativeLib64bit) {
+    private static int createRelros(@NonNull String packageName, @NonNull String libraryFileName) {
         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 (DEBUG) Log.v(LOGTAG, "Create 32 bit relro");
+            createRelroFile(false /* is64Bit */, packageName, libraryFileName);
+            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++;
-            }
+            if (DEBUG) Log.v(LOGTAG, "Create 64 bit relro");
+            createRelroFile(true /* is64Bit */, packageName, libraryFileName);
+            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);
+        boolean is64Bit = VMRuntime.getRuntime().is64Bit();
+        // On 64-bit address space is really cheap and we can reserve 1GB which is plenty.
+        // On 32-bit it's fairly scarce and we should keep it to a realistic number that
+        // permits some future growth but doesn't hog space: we use 100MB which is more than 2x
+        // the current requirement.
+        long addressSpaceToReserve = is64Bit ? 1 * 1024 * 1024 * 1024 : 100 * 1024 * 1024;
         sAddressSpaceReserved = nativeReserveAddressSpace(addressSpaceToReserve);
 
         if (sAddressSpaceReserved) {
@@ -253,106 +220,7 @@ public class WebViewLibraryLoader {
         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 boolean nativeCreateRelroFile(String lib, String relro, ClassLoader clazzLoader);
     static native int nativeLoadWithRelroFile(String lib, String relro, ClassLoader clazzLoader);
 }