tools: add pwd_reader from SLIP-0016

tools/pwd_reader.py

@@ -0,0 +1,173 @@
+#!/usr/bin/env python3
+
+from __future__ import print_function
+
+from binascii import hexlify, unhexlify
+from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
+from cryptography.hazmat.backends import default_backend
+import hmac
+import hashlib
+import json
+import os
+try:
+    from urllib.parse import urlparse
+except:
+    from urlparse import urlparse
+    input = raw_input
+
+from trezorlib.client import TrezorClient
+from trezorlib.transport_hid import HidTransport
+
+# Return path by BIP-32
+def getPath(client):
+    return client.expand_path("10016'/0")
+
+# Deriving master key
+def getMasterKey(client):
+    bip32_path = getPath(client)
+    ENC_KEY = 'Activate TREZOR Password Manager?'
+    ENC_VALUE = unhexlify('2d650551248d792eabf628f451200d7f51cb63e46aadcbb1038aacb05e8c8aee2d650551248d792eabf628f451200d7f51cb63e46aadcbb1038aacb05e8c8aee')
+    key = hexlify(client.encrypt_keyvalue(
+        bip32_path,
+        ENC_KEY,
+        ENC_VALUE,
+        True,
+        True
+    ))
+    return key
+
+# Deriving file name and encryption key
+def getFileEncKey(key):
+    filekey, enckey = key[:len(key) // 2], key[len(key) //2:]
+    FILENAME_MESS = b'5f91add3fa1c3c76e90c90a3bd0999e2bd7833d06a483fe884ee60397aca277a'
+    digest = hmac.new(filekey, FILENAME_MESS, hashlib.sha256).hexdigest()
+    filename = digest + '.pswd'
+    return [filename, filekey, enckey]
+
+# File level decryption and file reading
+def decryptStorage(path, key):
+    cipherkey = unhexlify(key)
+    with open(path, 'rb') as f:
+        iv = f.read(12)
+        tag = f.read(16)
+        cipher = Cipher(algorithms.AES(cipherkey), modes.GCM(iv, tag), backend=default_backend())
+        decryptor = cipher.decryptor()
+        data = ''
+        while True:
+            block = f.read(16)
+            # data are not authenticated yet
+            if block:
+                data = data + decryptor.update(block).decode()
+            else:
+                break
+        # throws exception when the tag is wrong
+        data = data + decryptor.finalize().decode()
+    return json.loads(data)
+
+def decryptEntryValue(nonce, val):
+    cipherkey = unhexlify(nonce)
+    iv = val[:12]
+    tag = val[12:28]
+    cipher = Cipher(algorithms.AES(cipherkey), modes.GCM(iv, tag), backend=default_backend())
+    decryptor = cipher.decryptor()
+    data = ''
+    inputData = val[28:]
+    while True:
+        block = inputData[:16]
+        inputData = inputData[16:]
+        if block:
+            data = data + decryptor.update(block).decode()
+        else:
+            break
+        # throws exception when the tag is wrong
+    data = data + decryptor.finalize().decode()
+    return json.loads(data)
+
+# Decrypt give entry nonce
+def getDecryptedNonce(client, entry):
+    print()
+    print('Waiting for TREZOR input ...')
+    print()
+    if 'item' in entry:
+        item = entry['item']
+    else:
+        item = entry['title']
+
+    pr = urlparse(item)
+    if pr.scheme and pr.netloc:
+        item = pr.netloc
+
+    ENC_KEY = 'Unlock %s for user %s?' % (item, entry['username'])
+    ENC_VALUE = entry['nonce']
+    decrypted_nonce =  hexlify(client.decrypt_keyvalue(
+        getPath(client),
+        ENC_KEY,
+        unhexlify(ENC_VALUE),
+        False,
+        True
+    ))
+    return decrypted_nonce
+
+# Pretty print of list
+def printEntries(entries):
+    print('Password entries')
+    print('================')
+    print()
+    for k, v in entries.items():
+        print('Entry id: #%s' % k)
+        print('-------------')
+        for kk, vv in v.items():
+            if kk in ['nonce', 'safe_note', 'password']: continue # skip these fields
+            print('*', kk, ': ', vv)
+        print()
+    return
+
+
+def main():
+    devices = HidTransport.enumerate()
+    if not devices:
+        print('TREZOR is not plugged in. Please, connect TREZOR and retry.')
+        return
+
+    client = TrezorClient(devices[0])
+
+    print()
+    print('Confirm operation on TREZOR')
+    print()
+
+    masterKey = getMasterKey(client)
+    # print('master key:', masterKey)
+
+    fileName = getFileEncKey(masterKey)[0]
+    # print('file name:', fileName)
+
+    path = os.path.expanduser('~/Dropbox/Apps/TREZOR Password Manager/')
+    # print('path to file:', path)
+
+    encKey = getFileEncKey(masterKey)[2]
+    # print('enckey:', encKey)
+
+    full_path = path + fileName
+    parsed_json = decryptStorage(full_path, encKey)
+
+    # list entries
+    entries = parsed_json['entries']
+    printEntries(entries)
+
+    entry_id = input('Select entry number to decrypt: ')
+    entry_id = str(entry_id)
+
+    plain_nonce = getDecryptedNonce(client, entries[entry_id])
+
+    pwdArr = entries[entry_id]['password']['data']
+    pwdHex = ''.join([ hex(x)[2:].zfill(2) for x in pwdArr ])
+    print('password: ', decryptEntryValue(plain_nonce, unhexlify(pwdHex)))
+
+    safeNoteArr = entries[entry_id]['safe_note']['data']
+    safeNoteHex = ''.join([ hex(x)[2:].zfill(2) for x in safeNoteArr ])
+    print('safe_note:', decryptEntryValue(plain_nonce, unhexlify(safeNoteHex)))
+
+    return
+
+if __name__ == '__main__':
+    main()