From 0667ac8c5f441facf2c94a1fe9ad339c8d840bea Mon Sep 17 00:00:00 2001
From: jesopo <github@lolnerd.net>
Date: Thu, 20 Feb 2020 14:56:04 +0000
Subject: [PATCH] add option to encrypt channel_log log files line-by-line

---
 docs/bot.conf.example  |  3 +++
 modules/channel_log.py | 14 ++++++++++----
 src/utils/security.py  | 27 ++++++++++++++++++++++++++-
 3 files changed, 39 insertions(+), 5 deletions(-)

diff --git a/docs/bot.conf.example b/docs/bot.conf.example
index 6c7808dc..7b1ad465 100644
--- a/docs/bot.conf.example
+++ b/docs/bot.conf.example
@@ -33,6 +33,9 @@ module-whitelist         =
 # path to an external directory for modules to be found in
 external-modules         =
 
+# optional PEM public key used to encrypt channel_log log lines
+log-key                  =
+
 # https://openweathermap.org/api
 openweathermap-api-key   =
 
diff --git a/modules/channel_log.py b/modules/channel_log.py
index 8344e9cd..a15d51f7 100644
--- a/modules/channel_log.py
+++ b/modules/channel_log.py
@@ -26,10 +26,16 @@ class Module(ModuleManager.BaseModule):
         return self.data_directory("%s/%s.log" % (server_name, sanitised_name))
     def _log(self, server, channel, line):
         if self._enabled(server, channel):
-            with open(self._file(str(server), str(channel)), "a") as log:
-                timestamp = utils.datetime.format.datetime_human(
-                    datetime.datetime.now())
-                log.write("%s %s\n" % (timestamp, line))
+            timestamp = utils.datetime.format.datetime_human(
+                datetime.datetime.now())
+            log_line = "%s %s" % (timestamp, line)
+
+            if "log-key" in self.bot.config:
+                log_line = "\x02%s" % utils.security.a_encrypt(
+                    self.bot.config["log-key"], log_line)
+
+            with open(self._file(str(server), str(channel)), "a") as log_file:
+                log_file.write("%s\n" % log_line)
 
     @utils.hook("formatted.message.channel")
     @utils.hook("formatted.notice.channel")
diff --git a/src/utils/security.py b/src/utils/security.py
index 78a54b5c..bb21a523 100644
--- a/src/utils/security.py
+++ b/src/utils/security.py
@@ -1,4 +1,4 @@
-import hmac, socket, ssl, typing
+import base64, hmac, socket, ssl, typing
 
 def ssl_context(cert: str=None, key: str=None, verify: bool=True
         ) -> ssl.SSLContext:
@@ -24,3 +24,28 @@ def ssl_wrap(sock: socket.socket, cert: str=None, key: str=None,
 
 def constant_time_compare(a: typing.AnyStr, b: typing.AnyStr) -> bool:
     return hmac.compare_digest(a, b)
+
+from cryptography.hazmat.backends import default_backend
+from cryptography.hazmat.primitives import serialization
+from cryptography.hazmat.primitives import hashes
+from cryptography.hazmat.primitives.asymmetric import padding
+
+def a_encrypt(key_filename: str, data: str):
+    with open(key_filename, "rb") as key_file:
+        key_content = key_file.read()
+    key = serialization.load_pem_public_key(
+        key_content, backend=default_backend())
+    out = key.encrypt(data.encode("utf8"), padding.OAEP(
+        mgf=padding.MGF1(algorithm=hashes.SHA256()),
+        algorithm=hashes.SHA256(), label=None))
+    return base64.b64encode(out).decode("iso-8859-1")
+
+def a_decrypt(key_filename: str, data: str):
+    with open(key_filename, "rb") as key_file:
+        key_content = key_file.read()
+    key = serialization.load_pem_private_key(
+        key_content, password=None, backend=default_backend())
+    out = key.decrypt(base64.b64decode(data), padding.OAEP(
+        mgf=padding.MGF1(algorithm=hashes.SHA256()),
+        algorithm=hashes.SHA256(), label=None))
+    return out.decode("utf8")