From 8460fdfd2a7c420f2f05a8fa6731d712b6b784ca Mon Sep 17 00:00:00 2001
From: derrod <xlnedder@gmail.com>
Date: Tue, 5 Oct 2021 07:34:52 +0200
Subject: [PATCH] [cli/core/lfs] Add support for trying multiple encryption
 keys

Should Epic change the key used for EGL in the future we want to
be backwards-compatible to existing (outdated) EGL installs as well
as new ones without having to push out a new release.

Also forces updating of version data before attempting the import to
get the latest key(s) and adds a log message when auth data is deleted.
---
 legendary/cli.py     |  9 +++++----
 legendary/core.py    | 18 +++++++++++++++---
 legendary/lfs/egl.py |  4 ++--
 3 files changed, 22 insertions(+), 9 deletions(-)

diff --git a/legendary/cli.py b/legendary/cli.py
index 6601c08..779f4d2 100644
--- a/legendary/cli.py
+++ b/legendary/cli.py
@@ -64,6 +64,7 @@ class LegendaryCLI:
     def auth(self, args):
         if args.auth_delete:
             self.core.lgd.invalidate_userdata()
+            logger.info('User data deleted.')
             return
 
         try:
@@ -78,6 +79,10 @@ class LegendaryCLI:
             logger.error('Stored credentials were found but were no longer valid. Continuing with login...')
             self.core.lgd.invalidate_userdata()
 
+        # Force an update check and notice in case there are API changes
+        self.core.check_for_updates(force=True)
+        self.core.force_show_update = True
+
         if args.import_egs_auth:
             # get appdata path on Linux
             if not self.core.egl.appdata_path:
@@ -128,10 +133,6 @@ class LegendaryCLI:
                 logger.error(f'No EGS login session found, please login manually. (Exception: {e!r})')
                 exit(1)
 
-        # Force an update check and notice in case there are API changes
-        self.core.check_for_updates(force=True)
-        self.core.force_show_update = True
-
         exchange_token = ''
         if not args.auth_code and not args.session_id:
             # unfortunately the captcha stuff makes a complete CLI login flow kinda impossible right now...
diff --git a/legendary/core.py b/legendary/core.py
index 2852a5e..85b0108 100644
--- a/legendary/core.py
+++ b/legendary/core.py
@@ -148,8 +148,18 @@ class LegendaryCore:
         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]
+            for data_key in self.egl.data_keys:
+                try:
+                    decrypted_data = decrypt_epic_data(data_key, raw_data)
+                    re_data = json.loads(decrypted_data)[0]
+                    break
+                except Exception as e:
+                    self.log.debug(f'Decryption with key {data_key} failed with {e!r}')
+            else:
+                raise ValueError('Decryption of EPIC launcher user information failed.')
+        else:
+            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']
@@ -245,7 +255,9 @@ 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)
+            for data_key in version_info['egl_config'].get('data_keys', []):
+                if data_key not in self.egl.data_keys:
+                    self.egl.data_keys.append(data_key)
         if game_overrides := version_info.get('game_overrides'):
             update_workarounds(game_overrides)
             if sdl_config := game_overrides.get('sdl_config'):
diff --git a/legendary/lfs/egl.py b/legendary/lfs/egl.py
index 78503f8..ea9b736 100644
--- a/legendary/lfs/egl.py
+++ b/legendary/lfs/egl.py
@@ -10,9 +10,9 @@ from legendary.models.egl import EGLManifest
 
 
 class EPCLFS:
-    # Encryption key for JSON data
+    # Known encryption key(s) for JSON user data
     # Data is encrypted using AES-256-ECB mode
-    data_key = 'A09C853C9E95409BB94D707EADEFA52E'
+    data_keys = []
 
     def __init__(self):
         if os.name == 'nt':