IsNativeAppInstalled

components/installedapp/android/java/src/org/chromium/device/installedapp/AssociationVerifier.java

+package org.chromium.components.installedapp;
+
+import android.content.pm.PackageManager;
+import android.content.pm.PackageManager.NameNotFoundException;
+import android.content.pm.PackageInfo;
+import android.content.pm.Signature;
+
+import android.content.res.Resources.NotFoundException;
+import android.content.res.Resources;
+
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Arrays;
+import java.util.Collections;
+
+import org.json.JSONArray;
+import org.json.JSONException;
+import org.json.JSONObject;
+
+public class AssociationVerifier {
+    private static final String ASSOCIATED_ASSETS_KEY = "associated_assets";
+    private static final String ASSET_DESCRIPTOR_FIELD_TARGET = "target";
+    private static final String ASSET_DESCRIPTOR_WEB = "web";
+    private static final String ASSET_DESCRIPTOR_FIELD_SITE = "site";
+    private static final String ASSET_DESCRIPTOR_FIELD_NAMESPACE = "namespace";
+
+    public static boolean verifyCertFingerprints(
+            String packageName, List<String> sha, PackageManager pm) {
+        Signature[] signatures;
+        try {
+            signatures = pm.getPackageInfo(packageName, PackageManager.GET_SIGNATURES).signatures;
+        } catch (NameNotFoundException e) {
+            return false;
+        }
+
+        // TODO: Convert this to an array.
+        HashSet<String> signatureStrings = new HashSet<String>(signatures.length);
+        for (Signature sig : signatures) {
+            signatureStrings.add(computeNormalizedSha256Fingerprint(sig.toByteArray()));
+        }
+
+        return signatureStrings.containsAll(sha) && sha.containsAll(signatureStrings);
+    }
+
+    private static List<String> getAssociations(String packageName, PackageManager pm) {
+        Resources resources;
+
+        try {
+            resources = pm.getResourcesForApplication(packageName);
+        } catch (NameNotFoundException e) {
+            return Collections.<String>emptyList();
+        }
+
+        if (resources == null) {
+            return Collections.<String>emptyList();
+        }
+
+        int identifier = resources.getIdentifier(ASSOCIATED_ASSETS_KEY, "array", packageName);
+        System.out.println("Identifier was " + identifier);
+        if (identifier == 0) {
+            return Collections.<String>emptyList();
+        }
+        return Arrays.asList(resources.getStringArray(identifier));
+    }
+
+    public static boolean isOriginAssociatedWithPackage(
+            String packageName, String origin, PackageManager pm) {
+        List<String> associations = getAssociations(packageName, pm);
+        // HashSet<String> associationSet = (new HashSet<>(associations));
+        // System.out.println(associationSet);
+
+        for (String statementString : associations) {
+            try {
+                JSONObject statement = new JSONObject(statementString);
+                String jsonOrigin = statement.getString(ASSET_DESCRIPTOR_FIELD_TARGET);
+                JSONObject webAsset = new JSONObject(jsonOrigin);
+                System.out.println(jsonOrigin);
+
+                // // TODO: Handle this.
+                // JSONArray relations = statement.getJSONArray(ASSET_DESCRIPTOR_FIELD_RELATION);
+                // for (int i = 0; i < relations.length(); i++) {
+                //     // statements.add(Statement
+                //     //         .create(source, target, Relation.create()));
+                // }
+
+                if (!webAsset.getString(ASSET_DESCRIPTOR_FIELD_NAMESPACE)
+                                .equals(ASSET_DESCRIPTOR_WEB)) {
+                    System.out.println("ASSET WAS NOT WEB");
+                    continue;
+                }
+
+                if (webAsset.getString(ASSET_DESCRIPTOR_FIELD_SITE).equals(origin)) {
+                    return true;
+                }
+                System.out.println(webAsset.getString(ASSET_DESCRIPTOR_FIELD_SITE)
+                        + " failed to match against " + origin);
+            } catch (JSONException e) {
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * Computes the hash of the byte array using the specified algorithm, returning a hex string
+     * with a colon between each byte.
+     */
+    public static String computeNormalizedSha256Fingerprint(byte[] cert) {
+        MessageDigest messageDigest;
+        try {
+            messageDigest = MessageDigest.getInstance("SHA-256");
+        } catch (NoSuchAlgorithmException e) {
+            throw new AssertionError("No SHA-256 implementation found.");
+        }
+        messageDigest.update(cert);
+        return byteArrayToHexString(messageDigest.digest());
+    }
+
+    /**
+ * Converts the byte array to an lowercase hexadecimal digits String with a colon character (:)
+ * between each byte.
+ */
+    private static final char[] HEX_DIGITS = {
+            '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};
+    private static String byteArrayToHexString(byte[] array) {
+        char[] hexString = new char[array.length * 3];
+        int index = 0;
+        for (byte b : array) {
+            hexString[index++] = HEX_DIGITS[(b >>> 4) & 0x0F];
+            hexString[index++] = HEX_DIGITS[b & 0x0F];
+            hexString[index++] = ':';
+        }
+
+        return new String(Arrays.copyOf(hexString, hexString.length - 1));
+    }
+}