Upstream: Add WebAPK's client library.

chrome/android/webapk/libs/client/src/org/chromium/webapk/lib/client/WebApkValidator.java

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.webapk.lib.client;
+
+import static org.chromium.webapk.lib.common.WebApkConstants.WEBAPK_PACKAGE_PREFIX;
+
+import android.content.Context;
+import android.content.Intent;
+import android.content.pm.PackageInfo;
+import android.content.pm.PackageManager;
+import android.content.pm.PackageManager.NameNotFoundException;
+import android.content.pm.ResolveInfo;
+import android.content.pm.Signature;
+import android.util.Log;
+
+import java.util.Arrays;
+import java.util.List;
+
+/**
+ * Checks whether a URL belongs to a WebAPK, and whether a WebAPK is signed by the WebAPK Minting
+ * Server.
+ */
+public class WebApkValidator {
+
+    private static final String TAG = "WebApkValidator";
+    private static byte[] sExpectedSignature;
+
+    /**
+     * Queries the PackageManager to determine whether a WebAPK can handle the URL. Ignores
+     * whether the user has selected a default handler for the URL and whether the default
+     * handler is the WebAPK.
+     *
+     * NOTE(yfriedman): This can fail if multiple WebAPKs can match the supplied url.
+     *
+     * @param context The application context.
+     * @param url The url to check.
+     * @return Package name of WebAPK which can handle the URL. Null if the url should not be
+     * handled by a WebAPK.
+     */
+    public static String queryWebApkPackage(Context context, String url) {
+        Intent intent;
+        try {
+            intent = Intent.parseUri(url, Intent.URI_INTENT_SCHEME);
+        } catch (Exception e) {
+            return null;
+        }
+
+        intent.addCategory(Intent.CATEGORY_BROWSABLE);
+        intent.setComponent(null);
+        Intent selector = intent.getSelector();
+        if (selector != null) {
+            selector.addCategory(Intent.CATEGORY_BROWSABLE);
+            selector.setComponent(null);
+        }
+
+        List<ResolveInfo> resolveInfos = context.getPackageManager().queryIntentActivities(
+                intent, PackageManager.GET_RESOLVED_FILTER);
+        return findWebApkPackage(resolveInfos);
+    }
+
+    /**
+     * @param The ResolveInfos to search.
+     * @return Package name of the ResolveInfo which corresponds to a WebAPK. Null if none of the
+     * ResolveInfos corresponds to a WebAPK.
+     */
+    public static String findWebApkPackage(List<ResolveInfo> infos) {
+        for (ResolveInfo info : infos) {
+            if (info.activityInfo != null
+                    && info.activityInfo.packageName.startsWith(WEBAPK_PACKAGE_PREFIX)) {
+                return info.activityInfo.packageName;
+            }
+        }
+        return null;
+    }
+
+    /**
+     * Returns whether the provided WebAPK is installed and passes signature checks.
+     * @param context A context
+     * @param webappPackageName The package name to check
+     * @return true iff the WebAPK is installed and passes security checks
+     */
+    public static boolean isValidWebApk(Context context, String webappPackageName) {
+        if (sExpectedSignature == null) {
+            Log.wtf(TAG, "WebApk validation failure - expected signature not set."
+                    + "missing call to WebApkValidator.initWithBrowserHostSignature");
+        }
+        if (webappPackageName != null && webappPackageName.startsWith(WEBAPK_PACKAGE_PREFIX)) {
+            // check signature
+            PackageInfo packageInfo = null;
+            try {
+                packageInfo = context.getPackageManager().getPackageInfo(webappPackageName,
+                        PackageManager.GET_SIGNATURES);
+            } catch (NameNotFoundException e) {
+                e.printStackTrace();
+                Log.d(TAG, "WebApk not found");
+                return false;
+            }
+
+            final Signature[] arrSignatures = packageInfo.signatures;
+            if (arrSignatures != null) {
+                for (Signature signature : arrSignatures) {
+                    if (Arrays.equals(sExpectedSignature, signature.toByteArray())) {
+                        Log.d(TAG, "WebApk valid - signature match!");
+                        return true;
+                    }
+                }
+            }
+        }
+        Log.d(TAG, "WebApk invalid");
+        return false;
+    }
+
+    /**
+     * Initializes the WebApkValidator with the expected signature that WebAPKs must be signed
+     * with for the current host.
+     * @param expectedSignature
+     */
+    public static void initWithBrowserHostSignature(byte[] expectedSignature) {
+        sExpectedSignature = Arrays.copyOf(expectedSignature, expectedSignature.length);
+    }
+}