[core/utils/lfs] Fix auth import with now encrypted EGL user data

It took way too long to find the key.
It's not even hidden, I'm just dumb.

legendary/core.py

@@ -31,6 +31,7 @@ from legendary.models.game import *
 from legendary.models.json_manifest import JSONManifest
 from legendary.models.manifest import Manifest, ManifestMeta
 from legendary.models.chunk import Chunk
+from legendary.utils.egl_crypt import decrypt_epic_data
 from legendary.utils.env import is_windows_or_pyi
 from legendary.utils.game_workarounds import is_opt_enabled, update_workarounds
 from legendary.utils.savegame_helper import SaveGameHelper
@@ -144,7 +145,11 @@ class LegendaryCore:
         """Import refresh token from EGL installation and use it for logging in"""
         self.egl.read_config()
         remember_me_data = self.egl.config.get('RememberMe', 'Data')
-        re_data = json.loads(b64decode(remember_me_data))[0]
+        raw_data = b64decode(remember_me_data)
+        # data is encrypted
+        if raw_data[0] != '{':
+            raw_data = decrypt_epic_data(self.egl.data_key, raw_data)
+        re_data = json.loads(raw_data)[0]
         if 'Token' not in re_data:
             raise ValueError('No login session in config')
         refresh_token = re_data['Token']
@@ -240,6 +245,7 @@ class LegendaryCore:
         if 'egl_config' in version_info:
             self.egs.update_egs_params(version_info['egl_config'])
             self._egl_version = version_info['egl_config'].get('version', self._egl_version)
+            self.egl.data_key = version_info['egl_config'].get('data_key', self.egl.data_key)
         if game_overrides := version_info.get('game_overrides'):
             update_workarounds(game_overrides)
             if sdl_config := game_overrides.get('sdl_config'):

legendary/lfs/egl.py

@@ -10,6 +10,10 @@ from legendary.models.egl import EGLManifest
 
 
 class EPCLFS:
+    # Encryption key for JSON data
+    # Data is encrypted using AES-256-ECB mode
+    data_key = 'A09C853C9E95409BB94D707EADEFA52E'
+
     def __init__(self):
         if os.name == 'nt':
             self.appdata_path = os.path.expandvars(

legendary/utils/egl_crypt.py

@@ -0,0 +1,248 @@
+"""
+Stripped down version of https://github.com/boppreh/aes which is in turn based
+on https://github.com/bozhu/AES-Python with ECB decryption added.
+
+You should practically never roll your own crypto like this.
+In this case it's just unimportant enough since all it needs to do is decrypt some data from the EGL config file.
+"""
+
+import locale
+
+s_box = (
+    0x63, 0x7C, 0x77, 0x7B, 0xF2, 0x6B, 0x6F, 0xC5, 0x30, 0x01, 0x67, 0x2B, 0xFE, 0xD7, 0xAB, 0x76,
+    0xCA, 0x82, 0xC9, 0x7D, 0xFA, 0x59, 0x47, 0xF0, 0xAD, 0xD4, 0xA2, 0xAF, 0x9C, 0xA4, 0x72, 0xC0,
+    0xB7, 0xFD, 0x93, 0x26, 0x36, 0x3F, 0xF7, 0xCC, 0x34, 0xA5, 0xE5, 0xF1, 0x71, 0xD8, 0x31, 0x15,
+    0x04, 0xC7, 0x23, 0xC3, 0x18, 0x96, 0x05, 0x9A, 0x07, 0x12, 0x80, 0xE2, 0xEB, 0x27, 0xB2, 0x75,
+    0x09, 0x83, 0x2C, 0x1A, 0x1B, 0x6E, 0x5A, 0xA0, 0x52, 0x3B, 0xD6, 0xB3, 0x29, 0xE3, 0x2F, 0x84,
+    0x53, 0xD1, 0x00, 0xED, 0x20, 0xFC, 0xB1, 0x5B, 0x6A, 0xCB, 0xBE, 0x39, 0x4A, 0x4C, 0x58, 0xCF,
+    0xD0, 0xEF, 0xAA, 0xFB, 0x43, 0x4D, 0x33, 0x85, 0x45, 0xF9, 0x02, 0x7F, 0x50, 0x3C, 0x9F, 0xA8,
+    0x51, 0xA3, 0x40, 0x8F, 0x92, 0x9D, 0x38, 0xF5, 0xBC, 0xB6, 0xDA, 0x21, 0x10, 0xFF, 0xF3, 0xD2,
+    0xCD, 0x0C, 0x13, 0xEC, 0x5F, 0x97, 0x44, 0x17, 0xC4, 0xA7, 0x7E, 0x3D, 0x64, 0x5D, 0x19, 0x73,
+    0x60, 0x81, 0x4F, 0xDC, 0x22, 0x2A, 0x90, 0x88, 0x46, 0xEE, 0xB8, 0x14, 0xDE, 0x5E, 0x0B, 0xDB,
+    0xE0, 0x32, 0x3A, 0x0A, 0x49, 0x06, 0x24, 0x5C, 0xC2, 0xD3, 0xAC, 0x62, 0x91, 0x95, 0xE4, 0x79,
+    0xE7, 0xC8, 0x37, 0x6D, 0x8D, 0xD5, 0x4E, 0xA9, 0x6C, 0x56, 0xF4, 0xEA, 0x65, 0x7A, 0xAE, 0x08,
+    0xBA, 0x78, 0x25, 0x2E, 0x1C, 0xA6, 0xB4, 0xC6, 0xE8, 0xDD, 0x74, 0x1F, 0x4B, 0xBD, 0x8B, 0x8A,
+    0x70, 0x3E, 0xB5, 0x66, 0x48, 0x03, 0xF6, 0x0E, 0x61, 0x35, 0x57, 0xB9, 0x86, 0xC1, 0x1D, 0x9E,
+    0xE1, 0xF8, 0x98, 0x11, 0x69, 0xD9, 0x8E, 0x94, 0x9B, 0x1E, 0x87, 0xE9, 0xCE, 0x55, 0x28, 0xDF,
+    0x8C, 0xA1, 0x89, 0x0D, 0xBF, 0xE6, 0x42, 0x68, 0x41, 0x99, 0x2D, 0x0F, 0xB0, 0x54, 0xBB, 0x16,
+)
+
+inv_s_box = (
+    0x52, 0x09, 0x6A, 0xD5, 0x30, 0x36, 0xA5, 0x38, 0xBF, 0x40, 0xA3, 0x9E, 0x81, 0xF3, 0xD7, 0xFB,
+    0x7C, 0xE3, 0x39, 0x82, 0x9B, 0x2F, 0xFF, 0x87, 0x34, 0x8E, 0x43, 0x44, 0xC4, 0xDE, 0xE9, 0xCB,
+    0x54, 0x7B, 0x94, 0x32, 0xA6, 0xC2, 0x23, 0x3D, 0xEE, 0x4C, 0x95, 0x0B, 0x42, 0xFA, 0xC3, 0x4E,
+    0x08, 0x2E, 0xA1, 0x66, 0x28, 0xD9, 0x24, 0xB2, 0x76, 0x5B, 0xA2, 0x49, 0x6D, 0x8B, 0xD1, 0x25,
+    0x72, 0xF8, 0xF6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xD4, 0xA4, 0x5C, 0xCC, 0x5D, 0x65, 0xB6, 0x92,
+    0x6C, 0x70, 0x48, 0x50, 0xFD, 0xED, 0xB9, 0xDA, 0x5E, 0x15, 0x46, 0x57, 0xA7, 0x8D, 0x9D, 0x84,
+    0x90, 0xD8, 0xAB, 0x00, 0x8C, 0xBC, 0xD3, 0x0A, 0xF7, 0xE4, 0x58, 0x05, 0xB8, 0xB3, 0x45, 0x06,
+    0xD0, 0x2C, 0x1E, 0x8F, 0xCA, 0x3F, 0x0F, 0x02, 0xC1, 0xAF, 0xBD, 0x03, 0x01, 0x13, 0x8A, 0x6B,
+    0x3A, 0x91, 0x11, 0x41, 0x4F, 0x67, 0xDC, 0xEA, 0x97, 0xF2, 0xCF, 0xCE, 0xF0, 0xB4, 0xE6, 0x73,
+    0x96, 0xAC, 0x74, 0x22, 0xE7, 0xAD, 0x35, 0x85, 0xE2, 0xF9, 0x37, 0xE8, 0x1C, 0x75, 0xDF, 0x6E,
+    0x47, 0xF1, 0x1A, 0x71, 0x1D, 0x29, 0xC5, 0x89, 0x6F, 0xB7, 0x62, 0x0E, 0xAA, 0x18, 0xBE, 0x1B,
+    0xFC, 0x56, 0x3E, 0x4B, 0xC6, 0xD2, 0x79, 0x20, 0x9A, 0xDB, 0xC0, 0xFE, 0x78, 0xCD, 0x5A, 0xF4,
+    0x1F, 0xDD, 0xA8, 0x33, 0x88, 0x07, 0xC7, 0x31, 0xB1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xEC, 0x5F,
+    0x60, 0x51, 0x7F, 0xA9, 0x19, 0xB5, 0x4A, 0x0D, 0x2D, 0xE5, 0x7A, 0x9F, 0x93, 0xC9, 0x9C, 0xEF,
+    0xA0, 0xE0, 0x3B, 0x4D, 0xAE, 0x2A, 0xF5, 0xB0, 0xC8, 0xEB, 0xBB, 0x3C, 0x83, 0x53, 0x99, 0x61,
+    0x17, 0x2B, 0x04, 0x7E, 0xBA, 0x77, 0xD6, 0x26, 0xE1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0C, 0x7D,
+)
+
+
+def sub_bytes(s):
+    for i in range(4):
+        for j in range(4):
+            s[i][j] = s_box[s[i][j]]
+
+
+def inv_sub_bytes(s):
+    for i in range(4):
+        for j in range(4):
+            s[i][j] = inv_s_box[s[i][j]]
+
+
+def shift_rows(s):
+    s[0][1], s[1][1], s[2][1], s[3][1] = s[1][1], s[2][1], s[3][1], s[0][1]
+    s[0][2], s[1][2], s[2][2], s[3][2] = s[2][2], s[3][2], s[0][2], s[1][2]
+    s[0][3], s[1][3], s[2][3], s[3][3] = s[3][3], s[0][3], s[1][3], s[2][3]
+
+
+def inv_shift_rows(s):
+    s[0][1], s[1][1], s[2][1], s[3][1] = s[3][1], s[0][1], s[1][1], s[2][1]
+    s[0][2], s[1][2], s[2][2], s[3][2] = s[2][2], s[3][2], s[0][2], s[1][2]
+    s[0][3], s[1][3], s[2][3], s[3][3] = s[1][3], s[2][3], s[3][3], s[0][3]
+
+
+def add_round_key(s, k):
+    for i in range(4):
+        for j in range(4):
+            s[i][j] ^= k[i][j]
+
+
+# learned from http://cs.ucsb.edu/~koc/cs178/projects/JT/aes.c
+xtime = lambda a: (((a << 1) ^ 0x1B) & 0xFF) if (a & 0x80) else (a << 1)
+
+
+def mix_single_column(a):
+    # see Sec 4.1.2 in The Design of Rijndael
+    t = a[0] ^ a[1] ^ a[2] ^ a[3]
+    u = a[0]
+    a[0] ^= t ^ xtime(a[0] ^ a[1])
+    a[1] ^= t ^ xtime(a[1] ^ a[2])
+    a[2] ^= t ^ xtime(a[2] ^ a[3])
+    a[3] ^= t ^ xtime(a[3] ^ u)
+
+
+def mix_columns(s):
+    for i in range(4):
+        mix_single_column(s[i])
+
+
+def inv_mix_columns(s):
+    # see Sec 4.1.3 in The Design of Rijndael
+    for i in range(4):
+        u = xtime(xtime(s[i][0] ^ s[i][2]))
+        v = xtime(xtime(s[i][1] ^ s[i][3]))
+        s[i][0] ^= u
+        s[i][1] ^= v
+        s[i][2] ^= u
+        s[i][3] ^= v
+
+    mix_columns(s)
+
+
+r_con = (
+    0x00, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40,
+    0x80, 0x1B, 0x36, 0x6C, 0xD8, 0xAB, 0x4D, 0x9A,
+    0x2F, 0x5E, 0xBC, 0x63, 0xC6, 0x97, 0x35, 0x6A,
+    0xD4, 0xB3, 0x7D, 0xFA, 0xEF, 0xC5, 0x91, 0x39,
+)
+
+
+def bytes2matrix(text):
+    """ Converts a 16-byte array into a 4x4 matrix.  """
+    return [list(text[i:i + 4]) for i in range(0, len(text), 4)]
+
+
+def matrix2bytes(matrix):
+    """ Converts a 4x4 matrix into a 16-byte array.  """
+    return bytes(sum(matrix, []))
+
+
+def xor_bytes(a, b):
+    """ Returns a new byte array with the elements xor'ed. """
+    return bytes(i ^ j for i, j in zip(a, b))
+
+
+def unpad(plaintext):
+    """
+    Removes a PKCS#7 padding, returning the unpadded text and ensuring the
+    padding was correct.
+    """
+    padding_len = plaintext[-1]
+    assert padding_len > 0
+    message, padding = plaintext[:-padding_len], plaintext[-padding_len:]
+    assert all(p == padding_len for p in padding)
+    return message
+
+
+def split_blocks(message, block_size=16, require_padding=True):
+    assert len(message) % block_size == 0 or not require_padding
+    return [message[i:i + 16] for i in range(0, len(message), block_size)]
+
+
+class AES:
+    """
+    Class for AES-128 encryption with CBC mode and PKCS#7.
+
+    This is a raw implementation of AES, without key stretching or IV
+    management. Unless you need that, please use `encrypt` and `decrypt`.
+    """
+    rounds_by_key_size = {16: 10, 24: 12, 32: 14}
+
+    def __init__(self, master_key):
+        """
+        Initializes the object with a given key.
+        """
+        assert len(master_key) in AES.rounds_by_key_size
+        self.n_rounds = AES.rounds_by_key_size[len(master_key)]
+        self._key_matrices = self._expand_key(master_key)
+
+    def _expand_key(self, master_key):
+        """
+        Expands and returns a list of key matrices for the given master_key.
+        """
+        # Initialize round keys with raw key material.
+        key_columns = bytes2matrix(master_key)
+        iteration_size = len(master_key) // 4
+
+        # Each iteration has exactly as many columns as the key material.
+        i = 1
+        while len(key_columns) < (self.n_rounds + 1) * 4:
+            # Copy previous word.
+            word = list(key_columns[-1])
+
+            # Perform schedule_core once every "row".
+            if len(key_columns) % iteration_size == 0:
+                # Circular shift.
+                word.append(word.pop(0))
+                # Map to S-BOX.
+                word = [s_box[b] for b in word]
+                # XOR with first byte of R-CON, since the others bytes of R-CON are 0.
+                word[0] ^= r_con[i]
+                i += 1
+            elif len(master_key) == 32 and len(key_columns) % iteration_size == 4:
+                # Run word through S-box in the fourth iteration when using a
+                # 256-bit key.
+                word = [s_box[b] for b in word]
+
+            # XOR with equivalent word from previous iteration.
+            word = xor_bytes(word, key_columns[-iteration_size])
+            key_columns.append(word)
+
+        # Group key words in 4x4 byte matrices.
+        return [key_columns[4 * i: 4 * (i + 1)] for i in range(len(key_columns) // 4)]
+
+    def decrypt_block(self, ciphertext):
+        """
+        Decrypts a single block of 16 byte long ciphertext.
+        """
+        assert len(ciphertext) == 16
+
+        cipher_state = bytes2matrix(ciphertext)
+
+        add_round_key(cipher_state, self._key_matrices[-1])
+        inv_shift_rows(cipher_state)
+        inv_sub_bytes(cipher_state)
+
+        for i in range(self.n_rounds - 1, 0, -1):
+            add_round_key(cipher_state, self._key_matrices[i])
+            inv_mix_columns(cipher_state)
+            inv_shift_rows(cipher_state)
+            inv_sub_bytes(cipher_state)
+
+        add_round_key(cipher_state, self._key_matrices[0])
+
+        return matrix2bytes(cipher_state)
+
+    def decrypt_ecb(self, ciphertext):
+        """
+        Decrypts `ciphertext` using ECB mode
+        """
+
+        blocks = []
+        for ciphertext_block in split_blocks(ciphertext, require_padding=False):
+            # CTR mode decrypt: ciphertext XOR encrypt(nonce)
+            block = self.decrypt_block(ciphertext_block)
+            blocks.append(block)
+
+        return b''.join(blocks)
+
+
+def decrypt_epic_data(key, encrypted):
+    decrypted = unpad(AES(key.encode('ascii')).decrypt_ecb(encrypted)).strip(b'\x00')
+    # try various encodings, just to be sure
+    for encoding in (locale.getpreferredencoding(), 'cp1252', 'cp932', 'ascii', 'utf-8'):
+        try:
+            return decrypted.decode(encoding)
+        except:  # ignore exception, just try the next encoding
+            continue
+    raise ValueError('Failed to decode decrypted data')