jrnl/jrnl/EncryptedJournal.py
2020-04-10 11:51:55 -07:00

125 lines
4.9 KiB
Python

from . import Journal, util
from cryptography.fernet import Fernet, InvalidToken
from cryptography.hazmat.primitives import hashes, padding
from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
import hashlib
from cryptography.hazmat.primitives.kdf.pbkdf2 import PBKDF2HMAC
from cryptography.hazmat.backends import default_backend
import sys
import os
import base64
import logging
log = logging.getLogger()
def make_key(password):
password = password.encode("utf-8")
kdf = PBKDF2HMAC(
algorithm=hashes.SHA256(),
length=32,
# Salt is hard-coded
salt=b'\xf2\xd5q\x0e\xc1\x8d.\xde\xdc\x8e6t\x89\x04\xce\xf8',
iterations=100000,
backend=default_backend()
)
key = kdf.derive(password)
return base64.urlsafe_b64encode(key)
class EncryptedJournal(Journal.Journal):
def __init__(self, name='default', **kwargs):
super().__init__(name, **kwargs)
self.config['encrypt'] = True
def open(self, filename=None):
"""Opens the journal file defined in the config and parses it into a list of Entries.
Entries have the form (date, title, body)."""
filename = filename or self.config['journal']
if not os.path.exists(filename):
password = util.create_password()
if password:
if util.yesno("Do you want to store the password in your keychain?", default=True):
util.set_keychain(self.name, password)
else:
util.set_keychain(self.name, None)
self.config['password'] = password
text = ""
self._store(filename, text)
print(f"[Journal '{self.name}' created at {filename}]", file=sys.stderr)
else:
print("No password supplied for encrypted journal", file=sys.stderr)
sys.exit(1)
else:
text = self._load(filename)
self.entries = self._parse(text)
self.sort()
log.debug("opened %s with %d entries", self.__class__.__name__, len(self))
return self
def _load(self, filename, password=None):
"""Loads an encrypted journal from a file and tries to decrypt it.
If password is not provided, will look for password in the keychain
and otherwise ask the user to enter a password up to three times.
If the password is provided but wrong (or corrupt), this will simply
return None."""
with open(filename, 'rb') as f:
journal_encrypted = f.read()
def validate_password(password):
key = make_key(password)
try:
plain = Fernet(key).decrypt(journal_encrypted).decode('utf-8')
self.config['password'] = password
return plain
except (InvalidToken, IndexError):
return None
if password:
return validate_password(password)
return util.get_password(keychain=self.name, validator=validate_password)
def _store(self, filename, text):
key = make_key(self.config['password'])
journal = Fernet(key).encrypt(text.encode('utf-8'))
with open(filename, 'wb') as f:
f.write(journal)
@classmethod
def _create(cls, filename, password):
key = make_key(password)
dummy = Fernet(key).encrypt(b"")
with open(filename, 'wb') as f:
f.write(dummy)
class LegacyEncryptedJournal(Journal.LegacyJournal):
"""Legacy class to support opening journals encrypted with the jrnl 1.x
standard. You'll not be able to save these journals anymore."""
def __init__(self, name='default', **kwargs):
super().__init__(name, **kwargs)
self.config['encrypt'] = True
def _load(self, filename, password=None):
with open(filename, 'rb') as f:
journal_encrypted = f.read()
iv, cipher = journal_encrypted[:16], journal_encrypted[16:]
def validate_password(password):
decryption_key = hashlib.sha256(password.encode('utf-8')).digest()
decryptor = Cipher(algorithms.AES(decryption_key), modes.CBC(iv), default_backend()).decryptor()
try:
plain_padded = decryptor.update(cipher) + decryptor.finalize()
self.config['password'] = password
if plain_padded[-1] in (" ", 32):
# Ancient versions of jrnl. Do not judge me.
return plain_padded.decode('utf-8').rstrip(" ")
else:
unpadder = padding.PKCS7(algorithms.AES.block_size).unpadder()
plain = unpadder.update(plain_padded) + unpadder.finalize()
return plain.decode('utf-8')
except ValueError:
return None
if password:
return validate_password(password)
return util.get_password(keychain=self.name, validator=validate_password)