| /* |
| * 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 com.android.server.devicepolicy; |
| |
| import android.annotation.NonNull; |
| import android.annotation.Nullable; |
| import android.util.AtomicFile; |
| import android.util.Slog; |
| |
| import java.io.BufferedInputStream; |
| import java.io.BufferedOutputStream; |
| import java.io.DataInputStream; |
| import java.io.DataOutputStream; |
| import java.io.File; |
| import java.io.FileOutputStream; |
| import java.io.FileNotFoundException; |
| import java.io.IOException; |
| import java.util.List; |
| |
| /** |
| * Manages the blacklisted passwords. |
| * |
| * This caller must ensure synchronized access. |
| */ |
| public class PasswordBlacklist { |
| private static final String TAG = "PasswordBlacklist"; |
| |
| private final AtomicFile mFile; |
| |
| /** |
| * Create an object to manage the password blacklist. |
| * |
| * This is a lightweight operation to prepare variables but not perform any IO. |
| */ |
| public PasswordBlacklist(File file) { |
| mFile = new AtomicFile(file, "device-policy"); |
| } |
| |
| /** |
| * Atomically replace the blacklist. |
| * |
| * Pass {@code null} for an empty list. |
| */ |
| public boolean savePasswordBlacklist(@NonNull String name, @NonNull List<String> blacklist) { |
| FileOutputStream fos = null; |
| try { |
| fos = mFile.startWrite(); |
| final DataOutputStream out = buildStreamForWriting(fos); |
| final Header header = new Header(Header.VERSION_1, name, blacklist.size()); |
| header.write(out); |
| final int blacklistSize = blacklist.size(); |
| for (int i = 0; i < blacklistSize; ++i) { |
| out.writeUTF(blacklist.get(i)); |
| } |
| out.flush(); |
| mFile.finishWrite(fos); |
| return true; |
| } catch (IOException e) { |
| mFile.failWrite(fos); |
| return false; |
| } |
| } |
| |
| /** @return the name of the blacklist or {@code null} if none set. */ |
| public String getName() { |
| try (DataInputStream in = openForReading()) { |
| return Header.read(in).mName; |
| } catch (IOException e) { |
| Slog.wtf(TAG, "Failed to read blacklist file", e); |
| } |
| return null; |
| } |
| |
| /** @return the number of blacklisted passwords. */ |
| public int getSize() { |
| final int blacklistSize; |
| try (DataInputStream in = openForReading()) { |
| return Header.read(in).mSize; |
| } catch (IOException e) { |
| Slog.wtf(TAG, "Failed to read blacklist file", e); |
| } |
| return 0; |
| } |
| |
| /** @return whether the password matches an blacklisted item. */ |
| public boolean isPasswordBlacklisted(@NonNull String password) { |
| final int blacklistSize; |
| try (DataInputStream in = openForReading()) { |
| final Header header = Header.read(in); |
| for (int i = 0; i < header.mSize; ++i) { |
| if (in.readUTF().equals(password)) { |
| return true; |
| } |
| } |
| } catch (IOException e) { |
| Slog.wtf(TAG, "Failed to read blacklist file", e); |
| // Fail safe and block all passwords. Setting a new blacklist should resolve this |
| // problem which can be identified by examining the log. |
| return true; |
| } |
| return false; |
| } |
| |
| /** Delete the blacklist completely from disk. */ |
| public void delete() { |
| mFile.delete(); |
| } |
| |
| /** Get the file the blacklist is stored in. */ |
| public File getFile() { |
| return mFile.getBaseFile(); |
| } |
| |
| private DataOutputStream buildStreamForWriting(FileOutputStream fos) { |
| return new DataOutputStream(new BufferedOutputStream(fos)); |
| } |
| |
| private DataInputStream openForReading() throws IOException { |
| return new DataInputStream(new BufferedInputStream(mFile.openRead())); |
| } |
| |
| /** |
| * Helper to read and write the header of the blacklist file. |
| */ |
| private static class Header { |
| static final int VERSION_1 = 1; |
| |
| final int mVersion; // File format version |
| final String mName; |
| final int mSize; |
| |
| Header(int version, String name, int size) { |
| mVersion = version; |
| mName = name; |
| mSize = size; |
| } |
| |
| void write(DataOutputStream out) throws IOException { |
| out.writeInt(mVersion); |
| out.writeUTF(mName); |
| out.writeInt(mSize); |
| } |
| |
| static Header read(DataInputStream in) throws IOException { |
| final int version = in.readInt(); |
| final String name = in.readUTF(); |
| final int size = in.readInt(); |
| return new Header(version, name, size); |
| } |
| } |
| } |