add option to let user add password to decrypt db key

code/decode.py

@@ -5,6 +5,8 @@ import logging
 from dataclasses import dataclass
 from collections import defaultdict
 
+from utils import decrypt_encrypted_key
+
 import pandas as pd
 from pandas import DataFrame
 from sklearn.feature_extraction import DictVectorizer
@@ -28,20 +30,22 @@ class Message:
     body: str
 
 
-def get_decryption_key(path):
+def get_decryption_key(path, password=None):
     with open(path) as fh:
         config = json.load(fh)
-    key = None
     if 'key' in config and 'encryptedKey' in config:
-        raise Exception('config has both key and encryptedKey in it')
+        raise Exception('config has both `key` and `encryptedKey` in it')
     if 'key' in config:
-        key = 'key'
+        if password is not None:
+            raise Exception('you cannot use the -p option with your signal config')
+        return config['key']
     elif 'encryptedKey' in config:
-        key = 'encryptedKey'
+        if password is None:
+            raise Exception('you must use the -p option to pass the password in for your signal db')
+        return decrypt_encrypted_key(password, config['encryptedKey'])
     else:
         dict_keys = ', '.join(str(x) for x in config.keys())
-        raise Exception(f'no key found for db in config.json, only saw: {dict_keys}')
+        raise Exception(f'no `key` or `encryptedKey` found for db in config.json, only saw: {dict_keys}')
-    return config[key]
 
 
 def query_signal_db(db, key, query):

code/main.py

@@ -8,6 +8,7 @@ table = subparsers.add_parser('table')
 table.set_defaults(func=dump_message_count_table)
 table.add_argument('--filter_file', '-f')
 table.add_argument('--output', '-o', default='table.csv')
+table.add_argument('--password', '-p')
 
 user = subparsers.add_parser('user')
 user.add_argument('regex')
@@ -21,10 +22,12 @@ parser.add_argument('--db',
                     default=expanduser('~/.config/Signal/sql/db.sqlite'))
 parser.add_argument('--config',
                     default=expanduser('~/.config/Signal/config.json'))
+
 if __name__ == "__main__":
     args = parser.parse_args()
-    key = get_decryption_key(args.config)
     args = vars(args)
+    password = args.pop('password')
+    key = get_decryption_key(args['config'], password)
     args.pop('config')
     func = args.pop('func')
     func(**args, key=key)

code/requirements.txt

@@ -1,2 +1,3 @@
 pandas
+pycryptodome
 scikit-learn

code/utils.py

@@ -0,0 +1,28 @@
+# from https://gist.github.com/flatz/3f242ab3c550d361f8c6d031b07fb6b1
+
+import os
+import json
+
+from Crypto.Protocol.KDF import PBKDF2
+from Crypto.Hash import SHA1
+from Crypto.Cipher import AES
+from Crypto.Util.Padding import unpad
+
+def aes_decrypt_cbc(key, iv, data):
+    cipher = AES.new(key, AES.MODE_CBC, iv)
+    return cipher.decrypt(data)
+
+prefix = b'v11'
+salt = 'saltysalt'
+derived_key_len = 128 // 8
+num_iterations = 1003
+iv = b' ' * 16
+
+def decrypt_encrypted_key(password, encrypted_key):
+    encrypted_key = bytes.fromhex(encrypted_key)
+    assert encrypted_key.startswith(prefix)
+    encrypted_key = encrypted_key[len(prefix):]
+
+    kek = PBKDF2(password, salt, dkLen = derived_key_len, count = num_iterations, hmac_hash_module = SHA1)
+    decrypted_key = unpad(aes_decrypt_cbc(kek, iv, encrypted_key), block_size = 16).decode('ascii')
+    print('0x' + decrypted_key)

run.sh

@@ -1,9 +1,10 @@
 #/usr/bin/sh
 
 FILTER=0
-while getopts "c:f" flag; do
+while getopts "c:p:f" flag; do
     case "$flag" in
         c) SIGNAL_DIR=$OPTARG;;
+        p) PASSWORD=$OPTARG;;
         f) FILTER=1;
     esac
 done
@@ -16,8 +17,17 @@ fi
 
 OUTDIR="$(pwd)/output"
 
-if [ $FILTER -eq 1 ]; then
+# TODO: learn how to use getopts and rewrite this. this is dumb.
-    docker run -it -v "$SIGNAL_DIR":/root/.config/Signal -v "$OUTDIR":/output -v "$(pwd)/config":/config sigint -f /config/chat_list.txt
+if [ -z "${PASSWORD+x}" ]; then
+    if [ $FILTER -eq 1 ]; then
+        docker run -it -v "$SIGNAL_DIR":/root/.config/Signal -v "$OUTDIR":/output -v "$(pwd)/config":/config sigint -f /config/chat_list.txt
+    else
+        docker run -it -v "$SIGNAL_DIR":/root/.config/Signal -v "$OUTDIR":/output sigint
+    fi
 else
-    docker run -it -v "$SIGNAL_DIR":/root/.config/Signal -v "$OUTDIR":/output sigint
+    if [ $FILTER -eq 1 ]; then
+        docker run -it -v "$SIGNAL_DIR":/root/.config/Signal -v "$OUTDIR":/output -v "$(pwd)/config":/config sigint -f /config/chat_list.txt --password "$PASSWORD"
+    else
+        docker run -it -v "$SIGNAL_DIR":/root/.config/Signal -v "$OUTDIR":/output sigint --password "$PASSWORD"
+    fi
 fi