| /* |
| * Copyright (C) 2016 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.util; |
| |
| import android.annotation.NonNull; |
| import android.annotation.Nullable; |
| import android.content.pm.PackageInfo; |
| import android.content.pm.PackageManager; |
| import android.content.pm.Signature; |
| |
| import java.security.MessageDigest; |
| import java.security.NoSuchAlgorithmException; |
| |
| /** |
| * Helper functions applicable to packages. |
| * @hide |
| */ |
| public final class PackageUtils { |
| private final static char[] HEX_ARRAY = "0123456789ABCDEF".toCharArray(); |
| |
| private PackageUtils() { |
| /* hide constructor */ |
| } |
| |
| /** |
| * Computes the SHA256 digest of the signing cert for a package. |
| * @param packageManager The package manager. |
| * @param packageName The package for which to generate the digest. |
| * @param userId The user for which to generate the digest. |
| * @return The digest or null if the package does not exist for this user. |
| */ |
| public static @Nullable String computePackageCertSha256Digest( |
| @NonNull PackageManager packageManager, |
| @NonNull String packageName, int userId) { |
| final PackageInfo packageInfo; |
| try { |
| packageInfo = packageManager.getPackageInfoAsUser(packageName, |
| PackageManager.GET_SIGNATURES, userId); |
| } catch (PackageManager.NameNotFoundException e) { |
| return null; |
| } |
| return computeCertSha256Digest(packageInfo.signatures[0]); |
| } |
| |
| /** |
| * Computes the SHA256 digest of a cert. |
| * @param signature The signature. |
| * @return The digest or null if an error occurs. |
| */ |
| public static @Nullable String computeCertSha256Digest(@NonNull Signature signature) { |
| return computeSha256Digest(signature.toByteArray()); |
| } |
| |
| /** |
| * Computes the SHA256 digest of some data. |
| * @param data The data. |
| * @return The digest or null if an error occurs. |
| */ |
| public static @Nullable String computeSha256Digest(@NonNull byte[] data) { |
| MessageDigest messageDigest; |
| try { |
| messageDigest = MessageDigest.getInstance("SHA256"); |
| } catch (NoSuchAlgorithmException e) { |
| /* can't happen */ |
| return null; |
| } |
| |
| messageDigest.update(data); |
| |
| final byte[] digest = messageDigest.digest(); |
| final int digestLength = digest.length; |
| final int charCount = 2 * digestLength; |
| |
| final char[] chars = new char[charCount]; |
| for (int i = 0; i < digestLength; i++) { |
| final int byteHex = digest[i] & 0xFF; |
| chars[i * 2] = HEX_ARRAY[byteHex >>> 4]; |
| chars[i * 2 + 1] = HEX_ARRAY[byteHex & 0x0F]; |
| } |
| return new String(chars); |
| } |
| } |