basic support for decrypting kdbx 3.x files

5 years ago · 4280997bf5
11 changed files with 345 additions and 39 deletions
--- a/.idea/codeStyles/codeStyleConfig.xml
+++ b/.idea/codeStyles/codeStyleConfig.xml
@ -0,0 +1,5 @@
+<component name="ProjectCodeStyleConfiguration">
+  <state>
+    <option name="USE_PER_PROJECT_SETTINGS" value="true" />
+  </state>
+</component>
--- a/README.md
+++ b/README.md
@ -4,7 +4,10 @@

 KeepassX format implementation in pure dart.

-Very much based on https://github.com/keeweb/kdbxweb/
+## Resources
+
+* Code is very much based on https://github.com/keeweb/kdbxweb/
+* https://gist.github.com/msmuenchen/9318327

 ## Usage

--- a/bin/kdbx.dart
+++ b/bin/kdbx.dart
@ -0,0 +1,91 @@
+import 'dart:async';
+import 'dart:io';
+
+import 'package:args/args.dart';
+import 'package:args/command_runner.dart';
+import 'package:kdbx/src/crypto/protected_value.dart';
+import 'package:kdbx/src/kdbx_format.dart';
+import 'package:kdbx/src/kdbx_header.dart';
+import 'package:logging/logging.dart';
+import 'package:logging_appenders/logging_appenders.dart';
+import 'package:prompts/prompts.dart' as prompts;
+
+final _logger = Logger('kdbx');
+
+void main(List<String> arguments) {
+  exitCode = 0;
+
+  final runner = KdbxCommandRunner('kdbx', 'Kdbx Utility');
+  runner.run(arguments).catchError((dynamic error, StackTrace stackTrace) {
+    if (error is! UsageException) {
+      return Future<dynamic>.error(error, stackTrace);
+    }
+    print(error);
+    exit(64);
+    return null;
+  });
+
+  //  final inputFile = args['input'] as String;
+//  if (inputFile == null) {
+//    print('Missing Argument --input');
+//    print(parser.usage);
+//    exitCode = 1;
+//    return;
+//  }
+  _logger.info('done.');
+}
+
+class KdbxCommandRunner extends CommandRunner<void> {
+  KdbxCommandRunner(String executableName, String description) : super(executableName, description) {
+    argParser.addFlag('verbose', abbr: 'v');
+    addCommand(CatCommand());
+  }
+
+  @override
+  Future<void> runCommand(ArgResults topLevelResults) {
+    PrintAppender().attachToLogger(Logger.root);
+    Logger.root.level = Level.INFO;
+    if (topLevelResults['verbose'] as bool) {
+      Logger.root.level = Level.ALL;
+    }
+    return super.runCommand(topLevelResults);
+  }
+}
+
+abstract class KdbxFileCommand extends Command<void> {
+  KdbxFileCommand() {
+    argParser.addOption(
+      'input',
+      abbr: 'i',
+      help: 'Input kdbx file',
+      valueHelp: 'foo.kdbx',
+    );
+  }
+
+  @override
+  FutureOr<void> run() async {
+    final inputFile = argResults['input'] as String;
+    if (inputFile == null) {
+      usageException('Required argument: --input');
+    }
+    final bytes = await File(inputFile).readAsBytes();
+    final password = prompts.get('Password for $inputFile', conceal: true, validate: (str) => str.isNotEmpty);
+    final file = await KdbxFormat.read(bytes, Credentials(ProtectedValue.fromString(password)));
+    return runWithFile(file);
+  }
+
+  Future<void> runWithFile(KdbxFile file);
+}
+
+class CatCommand extends KdbxFileCommand {
+  @override
+  String get description => 'outputs all entries from file.';
+
+  @override
+  String get name => 'cat';
+
+  @override
+  Future<void> runWithFile(KdbxFile file) async {
+    _logger.severe('running');
+  }
+}
--- a/lib/src/crypto/protected_salt_generator.dart
+++ b/lib/src/crypto/protected_salt_generator.dart
@ -0,0 +1,25 @@
+import 'dart:convert';
+import 'dart:typed_data';
+
+import 'package:crypto/crypto.dart';
+import 'package:pointycastle/export.dart';
+
+class ProtectedSaltGenerator {
+  factory ProtectedSaltGenerator(Uint8List key) {
+    final hash = sha256.convert(key).bytes as Uint8List;
+    final cipher = Salsa20Engine()..init(false, ParametersWithIV(KeyParameter(hash), SalsaNonce));
+    return ProtectedSaltGenerator._(cipher);
+  }
+
+  ProtectedSaltGenerator._(this.cipher);
+
+  static final SalsaNonce = Uint8List.fromList([0xE8, 0x30, 0x09, 0x4B, 0x97, 0x20, 0x5D, 0x2A]);
+  final StreamCipher cipher;
+
+  String decryptBase64(String protectedValue) {
+    final bytes = base64.decode(protectedValue);
+    final result = cipher.process(bytes);
+    final decrypted = utf8.decode(result);
+    return decrypted;
+  }
+}
--- a/lib/src/internal/crypto_utils.dart
+++ b/lib/src/internal/crypto_utils.dart
@ -4,10 +4,6 @@ import 'dart:typed_data';

 import 'package:pointycastle/export.dart';

-class CryptoUtils {
-
-}
-
 /// https://gist.github.com/proteye/e54eef1713e1fe9123d1eb04c0a5cf9b
 class AesHelper {
  static const CBC_MODE = 'CBC';
--- a/lib/src/kdbx_entry.dart
+++ b/lib/src/kdbx_entry.dart
@ -0,0 +1,5 @@
+
+
+class KdbxEntry {
+
+}
--- a/lib/src/kdbx_format.dart
+++ b/lib/src/kdbx_format.dart
@ -3,23 +3,48 @@ import 'dart:io';
 import 'dart:typed_data';

 import 'package:crypto/crypto.dart' as crypto;
+import 'package:kdbx/src/crypto/protected_salt_generator.dart';
+import 'package:kdbx/src/crypto/protected_value.dart';
 import 'package:kdbx/src/internal/byte_utils.dart';
 import 'package:kdbx/src/internal/crypto_utils.dart';
 import 'package:kdbx/src/kdbx_header.dart';
 import 'package:logging/logging.dart';
 import 'package:pointycastle/export.dart';
+import 'package:xml/xml.dart' as xml;

 final _logger = Logger('kdbx.format');

+class KdbxFile {
+  KdbxFile(this.credentials, this.header, this.body);
+
+  static final protectedValues = Expando<ProtectedValue>();
+
+  final Credentials credentials;
+  final KdbxHeader header;
+  final KdbxBody body;
+}
+
+class KdbxBody {
+  KdbxBody(this.xmlDocument, this.meta);
+
+  final xml.XmlDocument xmlDocument;
+  final KdbxMeta meta;
+}
+
+class KdbxMeta {
+
+}

 class KdbxFormat {
-  static Future<void> read(Uint8List input, Credentials credentials) async {
+
+  static Future<KdbxFile> read(Uint8List input, Credentials credentials) async {
    final reader = ReaderHelper(input);
    final header = await KdbxHeader.read(reader);
-    _loadV3(header, reader, credentials);
+    return _loadV3(header, reader, credentials);
  }

-  static void _loadV3(KdbxHeader header, ReaderHelper reader, Credentials credentials) {
+  static KdbxFile _loadV3(
+      KdbxHeader header, ReaderHelper reader, Credentials credentials) {
 //    _getMasterKeyV3(header, credentials);
    final masterKey = _generateMasterKeyV3(header, credentials);
    final encryptedPayload = reader.readRemaining();
@ -30,54 +55,80 @@ class KdbxFormat {
    if (header.compression == Compression.gzip) {
      final xml = GZipCodec().decode(blocks);
      final string = utf8.decode(xml);
-      print('xml: $string');
+      return KdbxFile(credentials, header, _loadXml(header, string));
+    } else {
+      return KdbxFile(credentials, header, _loadXml(header, utf8.decode(blocks)));
+    }
+  }
+
+  static KdbxBody _loadXml(KdbxHeader header, String xmlString) {
+    final protectedValueEncryption = header.innerRandomStreamEncryption;
+    if (protectedValueEncryption != PotectedValueEncryption.salsa20) {
+      throw KdbxUnsupportedException(
+          'Inner encryption: $protectedValueEncryption');
    }
+    final streamKey =
+        header.fields[HeaderFields.ProtectedStreamKey].bytes.asUint8List();
+    final gen = ProtectedSaltGenerator(streamKey);
+
+    final document = xml.parse(xmlString);

-//    final result = utf8.decode(decrypted);
-//    final aesEngine = AESFastEngine();
-//    aesEngine.init(true, KeyParameter(seed));
-//    final key = AesHelper.deriveKey(keyComposite.bytes as Uint8List, salt: seed, iterationCount: rounds, derivedKeyLength: 32);
-//    final masterKey = Uint8List.fromList(key + masterSeed.asUint8List());
-//    print('key length: ${key.length} + ${masterSeed.lengthInBytes} = ${masterKey.lengthInBytes} (${masterKey.lengthInBytes} bytes)');
+    for (final el in document
+        .findAllElements('Value')
+        .where((el) => el.getAttribute('Protected')?.toLowerCase() == 'true')) {
+      final pw = gen.decryptBase64(el.text.trim());
+      KdbxFile.protectedValues[el] = ProtectedValue.fromString(pw);
+    }

-//    final result = AesHelper.decrypt(masterKey, reader.readRemaining());
-//    print('before     : ${_toHexList(encryptedPayload)}');
+    final keePassFile = document.findElements('KeePassFile').single;
+    final meta = keePassFile.findElements('Meta').single;
+    final groupRoot = keePassFile.findElements('Root').single;
+    _logger.fine('got meta: ${meta.toXmlString(pretty: true)}');
+    return KdbxBody(document, KdbxMeta());
  }

-  static Uint8List _decryptContent(KdbxHeader header, Uint8List masterKey, Uint8List encryptedPayload) {
+  static Uint8List _decryptContent(
+      KdbxHeader header, Uint8List masterKey, Uint8List encryptedPayload) {
    final encryptionIv = header.fields[HeaderFields.EncryptionIV].bytes;
    final decryptCipher = CBCBlockCipher(AESFastEngine());
-    decryptCipher.init(false, ParametersWithIV(KeyParameter(masterKey), encryptionIv.asUint8List()));
+    decryptCipher.init(false,
+        ParametersWithIV(KeyParameter(masterKey), encryptionIv.asUint8List()));
    final decrypted = AesHelper.processBlocks(decryptCipher, encryptedPayload);

    final streamStart = header.fields[HeaderFields.StreamStartBytes].bytes;

-    _logger.finest('streamStart: ${ByteUtils.toHexList(streamStart.asUint8List())}');
-    _logger.finest('actual     : ${ByteUtils.toHexList(decrypted.sublist(0, streamStart.lengthInBytes))}');
+    _logger.finest(
+        'streamStart: ${ByteUtils.toHexList(streamStart.asUint8List())}');
+    _logger.finest(
+        'actual     : ${ByteUtils.toHexList(decrypted.sublist(0, streamStart.lengthInBytes))}');

-    if (!ByteUtils.eq(streamStart.asUint8List(), decrypted.sublist(0, streamStart.lengthInBytes))) {
+    if (!ByteUtils.eq(streamStart.asUint8List(),
+        decrypted.sublist(0, streamStart.lengthInBytes))) {
      throw KdbxInvalidKeyException();
    }
    final content = decrypted.sublist(streamStart.lengthInBytes);
    return content;
  }

-  static Uint8List _generateMasterKeyV3(KdbxHeader header, Credentials credentials) {
-    final rounds = header.fields[HeaderFields.TransformRounds].bytes.asUint64List().first;
+  static Uint8List _generateMasterKeyV3(
+      KdbxHeader header, Credentials credentials) {
+    final rounds =
+        header.fields[HeaderFields.TransformRounds].bytes.asUint64List().first;
    final seed = header.fields[HeaderFields.TransformSeed].bytes.asUint8List();
    final masterSeed = header.fields[HeaderFields.MasterSeed].bytes;
    _logger.finer('Rounds: $rounds');

-    final cipher = ECBBlockCipher(AESFastEngine())..init(true, KeyParameter(seed));
+    final cipher = ECBBlockCipher(AESFastEngine())
+      ..init(true, KeyParameter(seed));
    final pwHash = credentials.getHash();
    var transformedKey = pwHash;
    for (int i = 0; i < rounds; i++) {
      transformedKey = AesHelper.processBlocks(cipher, transformedKey);
    }
    transformedKey = crypto.sha256.convert(transformedKey).bytes as Uint8List;
-    final masterKey =
-    crypto.sha256.convert(Uint8List.fromList(masterSeed.asUint8List() + transformedKey)).bytes as Uint8List;
+    final masterKey = crypto.sha256
+        .convert(Uint8List.fromList(masterSeed.asUint8List() + transformedKey))
+        .bytes as Uint8List;
    return masterKey;
  }
-
 }
--- a/lib/src/kdbx_group.dart
+++ b/lib/src/kdbx_group.dart
@ -0,0 +1,4 @@
+
+class KdbxGroup {
+
+}
--- a/lib/src/kdbx_header.dart
+++ b/lib/src/kdbx_header.dart
@ -1,5 +1,3 @@
-import 'dart:convert';
-import 'dart:io';
 import 'dart:typed_data';

 import 'package:convert/convert.dart' as convert;
@ -7,7 +5,6 @@ import 'package:crypto/crypto.dart' as crypto;
 import 'package:kdbx/src/crypto/protected_value.dart';
 import 'package:kdbx/src/internal/byte_utils.dart';
 import 'package:logging/logging.dart';
-import 'package:pointycastle/export.dart';

 final _logger = Logger('kdbx.header');

@ -25,6 +22,9 @@ enum Compression {
  gzip,
 }

+/// how protected values are encrypted in the xml.
+enum PotectedValueEncryption { plainText, arc4variant, salsa20 }
+
 enum HeaderFields {
  EndOfHeader,
  Comment,
@ -79,9 +79,9 @@ class KdbxHeader {
  static Iterable<HeaderField> readField(ReaderHelper reader, int versionMajor) sync* {
    while (true) {
      final headerId = reader.readUint8();
-      int size = versionMajor >= 4 ? reader.readUint32() : reader.readUint16();
+      final int bodySize = versionMajor >= 4 ? reader.readUint32() : reader.readUint16();
      _logger.finer('Read header ${HeaderFields.values[headerId]}');
-      final bodyBytes = size > 0 ? reader.readBytes(size) : null;
+      final bodyBytes = bodySize > 0 ? reader.readBytes(bodySize) : null;
      if (headerId > 0) {
        yield HeaderField(HeaderFields.values[headerId], bodyBytes);
      } else {
@ -106,6 +106,9 @@ class KdbxHeader {
        throw KdbxUnsupportedException('compression');
    }
  }
+
+  PotectedValueEncryption get innerRandomStreamEncryption =>
+      PotectedValueEncryption.values[fields[HeaderFields.InnerRandomStreamID].bytes.asUint32List().single];
 }

 class Credentials {
@ -134,8 +137,6 @@ class KdbxUnsupportedException implements KdbxException {
  final String hint;
 }

-
-
 class HashedBlockReader {
  static Uint8List readBlocks(ReaderHelper reader) =>
      Uint8List.fromList(readNextBlock(reader).expand((x) => x).toList());
@ -176,4 +177,3 @@ class ReaderHelper {

  Uint8List readRemaining() => data.sublist(pos);
 }
-
--- a/pubspec.yaml
+++ b/pubspec.yaml
@ -11,10 +11,14 @@ dependencies:
 #  path: ^1.6.0
  logging: '>=0.11.3+2 <1.0.0'
  crypto: '>=2.0.0 <3.0.0'
-  pointycastle: ^1.0.1
-  xml: ^3.5.0
+  pointycastle: '>=1.0.1 <2.0.0'
+  xml: '>=3.5.0 <4.0.0'

-dev_dependencies:
+  # required for bin/
+  args: '>1.5.0 <2.0.0'
+  prompts: '>=1.3.0 <2.0.0'
  logging_appenders: '>=0.1.0 <1.0.0'
+
+dev_dependencies:
  pedantic: ^1.7.0
  test: ^1.6.0
--- a/test/FooBar.2.content.xml
+++ b/test/FooBar.2.content.xml
@ -0,0 +1,122 @@
+<?xml version="1.0" encoding="utf-8" standalone="yes"?>
+<KeePassFile>
+    <Meta>
+        <Generator>KdbxWeb</Generator>
+        <HeaderHash>r9uD96EiudcSeXq62ma/OqtBBPf+EYX7iMrBaNJBRwo=</HeaderHash>
+        <DatabaseName>FooBar</DatabaseName>
+        <DatabaseNameChanged>2019-08-20T13:16:06Z</DatabaseNameChanged>
+        <DatabaseDescription />
+        <DatabaseDescriptionChanged>2019-08-20T13:15:47Z</DatabaseDescriptionChanged>
+        <DefaultUserName />
+        <DefaultUserNameChanged>2019-08-20T13:15:47Z</DefaultUserNameChanged>
+        <MaintenanceHistoryDays>365</MaintenanceHistoryDays>
+        <Color />
+        <MasterKeyChanged>2019-08-20T13:16:03Z</MasterKeyChanged>
+        <MasterKeyChangeRec>-1</MasterKeyChangeRec>
+        <MasterKeyChangeForce>-1</MasterKeyChangeForce>
+        <RecycleBinEnabled>True</RecycleBinEnabled>
+        <RecycleBinUUID>dVSBC/BAx70qcsy6XkrGJA==</RecycleBinUUID>
+        <RecycleBinChanged>2019-08-20T13:15:47Z</RecycleBinChanged>
+        <EntryTemplatesGroup>AAAAAAAAAAAAAAAAAAAAAA==</EntryTemplatesGroup>
+        <EntryTemplatesGroupChanged>2019-08-20T13:15:47Z</EntryTemplatesGroupChanged>
+        <HistoryMaxItems>10</HistoryMaxItems>
+        <HistoryMaxSize>6291456</HistoryMaxSize>
+        <LastSelectedGroup />
+        <LastTopVisibleGroup />
+        <MemoryProtection>
+            <ProtectTitle>False</ProtectTitle>
+            <ProtectUserName>False</ProtectUserName>
+            <ProtectPassword>True</ProtectPassword>
+            <ProtectURL>False</ProtectURL>
+            <ProtectNotes>False</ProtectNotes>
+        </MemoryProtection>
+        <CustomIcons />
+        <Binaries />
+        <CustomData />
+    </Meta>
+    <Root>
+        <Group>
+            <UUID>LAQMkihXTkxhA2D2tE40Fg==</UUID>
+            <Name>FooBar</Name>
+            <Notes />
+            <IconID>49</IconID>
+            <Times>
+                <CreationTime>2019-08-20T13:15:47Z</CreationTime>
+                <LastModificationTime>2019-08-20T13:16:06Z</LastModificationTime>
+                <LastAccessTime>2019-08-20T13:16:06Z</LastAccessTime>
+                <ExpiryTime>2019-08-20T13:15:47Z</ExpiryTime>
+                <Expires>False</Expires>
+                <UsageCount>0</UsageCount>
+                <LocationChanged>2019-08-20T13:15:47Z</LocationChanged>
+            </Times>
+            <IsExpanded>True</IsExpanded>
+            <DefaultAutoTypeSequence />
+            <EnableAutoType>null</EnableAutoType>
+            <EnableSearching>null</EnableSearching>
+            <LastTopVisibleEntry>AAAAAAAAAAAAAAAAAAAAAA==</LastTopVisibleEntry>
+            <Group>
+                <UUID>dVSBC/BAx70qcsy6XkrGJA==</UUID>
+                <Name>Recycle Bin</Name>
+                <Notes />
+                <IconID>43</IconID>
+                <Times>
+                    <CreationTime>2019-08-20T13:15:47Z</CreationTime>
+                    <LastModificationTime>2019-08-20T13:15:47Z</LastModificationTime>
+                    <LastAccessTime>2019-08-20T13:15:47Z</LastAccessTime>
+                    <ExpiryTime>2019-08-20T13:15:47Z</ExpiryTime>
+                    <Expires>False</Expires>
+                    <UsageCount>0</UsageCount>
+                    <LocationChanged>2019-08-20T13:15:47Z</LocationChanged>
+                </Times>
+                <IsExpanded>True</IsExpanded>
+                <DefaultAutoTypeSequence />
+                <EnableAutoType>False</EnableAutoType>
+                <EnableSearching>False</EnableSearching>
+                <LastTopVisibleEntry>AAAAAAAAAAAAAAAAAAAAAA==</LastTopVisibleEntry>
+            </Group>
+            <Entry>
+                <UUID>RMUeiV24MDcrIY8qQYRAlg==</UUID>
+                <IconID>0</IconID>
+                <ForegroundColor />
+                <BackgroundColor />
+                <OverrideURL />
+                <Tags />
+                <Times>
+                    <CreationTime>2019-08-21T00:17:25Z</CreationTime>
+                    <LastModificationTime>2019-08-21T00:17:36Z</LastModificationTime>
+                    <LastAccessTime>2019-08-21T00:17:36Z</LastAccessTime>
+                    <ExpiryTime>2019-08-21T00:17:25Z</ExpiryTime>
+                    <Expires>False</Expires>
+                    <UsageCount>0</UsageCount>
+                    <LocationChanged>2019-08-21T00:17:25Z</LocationChanged>
+                </Times>
+                <String>
+                    <Key>Title</Key>
+                    <Value>loremipsum.com</Value>
+                </String>
+                <String>
+                    <Key>UserName</Key>
+                    <Value>foo</Value>
+                </String>
+                <String>
+                    <Key>Password</Key>
+                    <Value Protected="True">QcvZ</Value>
+                </String>
+                <String>
+                    <Key>URL</Key>
+                    <Value />
+                </String>
+                <String>
+                    <Key>Notes</Key>
+                    <Value />
+                </String>
+                <AutoType>
+                    <Enabled>True</Enabled>
+                    <DataTransferObfuscation>0</DataTransferObfuscation>
+                </AutoType>
+                <History />
+            </Entry>
+        </Group>
+        <DeletedObjects />
+    </Root>
+</KeePassFile>