From bb06293031422c5821f33638b115b641c0bb7417 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?poljar=20=28Damir=20Jeli=C4=87=29?= <poljar@termina.org.uk>
Date: Thu, 17 May 2018 12:59:07 +0200
Subject: [PATCH] encryption: Initial device verification support.

---
 matrix/encryption.py | 66 +++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 65 insertions(+), 1 deletion(-)

diff --git a/matrix/encryption.py b/matrix/encryption.py
index 7734838..cd3ffa7 100644
--- a/matrix/encryption.py
+++ b/matrix/encryption.py
@@ -27,6 +27,7 @@ import argparse
 from builtins import str, bytes
 
 from collections import defaultdict
+from itertools import chain
 from functools import wraps
 from future.moves.itertools import zip_longest
 
@@ -207,6 +208,45 @@ def olm_info_command(server, args):
                 W.prnt(server.server_buffer, message)
 
 
+def olm_verify_command(server, args):
+    olm = server.olm
+    devices = olm.device_keys
+    filtered_devices = []
+
+    if args.user_filter == "*":
+        filtered_devices = devices.values()
+    else:
+        device_keys = filter(lambda x: args.user_filter in x, devices)
+        filtered_devices = [devices[x] for x in device_keys]
+
+    filtered_devices = chain.from_iterable(filtered_devices)
+
+    if args.device_filter and args.device_filter != "*":
+        filtered_devices = filter(
+            lambda x: args.device_filter in x.device_id,
+            filtered_devices
+        )
+
+    key_list = []
+
+    for device in list(filtered_devices):
+        if olm.verify_device(device):
+            key_list.append(str(device))
+
+    if not key_list:
+        message = ("{prefix}matrix: No matching unverified devices "
+                   "found.").format(prefix=W.prefix("error"))
+        W.prnt(server.server_buffer, message)
+        return
+
+    key_str = "\n  - ".join(key_list)
+    message = ("{prefix}matrix: Verified keys:\n"
+               "  - {key_str}").format(prefix=W.prefix("join"),
+                                       key_str=key_str)
+
+    W.prnt(server.server_buffer, message)
+
+
 @own_buffer_or_error
 @utf8_decode
 def matrix_olm_command_cb(server_name, buffer, args):
@@ -218,6 +258,8 @@ def matrix_olm_command_cb(server_name, buffer, args):
 
     if not parsed_args.subcommand or parsed_args.subcommand == "info":
         olm_info_command(server, parsed_args)
+    elif parsed_args.subcommand == "verify":
+        olm_verify_command(server, parsed_args)
     else:
         message = ("{prefix}matrix: Command not implemented.".format(
             prefix=W.prefix("error")))
@@ -351,7 +393,7 @@ class StoreEntry(object):
     def to_line(self):
         # type: () -> str
         key_type = "matrix-{}".format(self.key_type)
-        line = "{} {} {} {}".format(
+        line = "{} {} {} {}\n".format(
             self.user_id,
             self.device_id,
             key_type,
@@ -391,6 +433,15 @@ class OlmDeviceKey():
         self.device_id = device_id
         self.keys = key_dict
 
+    def __str__(self):
+        # type: () -> str
+        return "{} {} {}".format(
+            self.user_id, self.device_id, self.keys["ed25519"])
+
+    def __repr__(self):
+        # type: () -> str
+        return str(self)
+
 
 class OneTimeKey():
     def __init__(self, user_id, device_id, key):
@@ -443,6 +494,9 @@ class Olm():
         self.inbound_group_sessions = inbound_group_sessions
         self.outbound_group_sessions = {}
 
+        trust_file_path = "{}_{}.trusted_devices".format(user, device_id)
+        self.trust_db = DeviceStore(os.path.join(session_path, trust_file_path))
+
     def _create_session(self, sender, sender_key, message):
         W.prnt("", "matrix: Creating session for {}".format(sender))
         session = InboundSession(self.account, message, sender_key)
@@ -452,6 +506,16 @@ class Olm():
 
         return session
 
+    def verify_device(self, device):
+        if self.trust_db.check(device):
+            return False
+
+        self.trust_db.add(device)
+        return True
+
+    def unverify_device(self, device):
+        self.trust_db.remove(device)
+
     def create_session(self, user_id, device_id, one_time_key):
         W.prnt("", "matrix: Creating session for {}".format(user_id))
         id_key = None