Add file hash blocking capabilities into automod

techsupport_bot/core/auxiliary.py

@@ -5,6 +5,7 @@
 
 from __future__ import annotations
 
+import hashlib
 import json
 from functools import wraps
 from typing import TYPE_CHECKING, Any
@@ -529,3 +530,16 @@ async def bot_admin_check_interaction(interaction: discord.Interaction) -> bool:
     if not is_admin:
         raise app_commands.MissingPermissions(["bot_admin"])
     return True
+
+
+async def get_attachment_hash(attachment: discord.Attachment) -> str:
+    """Computes a sha256 file hash for a given discord attachment
+
+    Args:
+        attachment (discord.Attachment): The attachment to generate the hash of
+
+    Returns:
+        str: The hash, as a string
+    """
+    file_bytes = await attachment.read()
+    return hashlib.sha256(file_bytes).hexdigest()

techsupport_bot/functions/automod.py

@@ -11,7 +11,7 @@
 import munch
 from botlogging import LogContext, LogLevel
 from commands import moderator, modlog
-from core import cogs, extensionconfig, moderation
+from core import auxiliary, cogs, extensionconfig, moderation
 from discord.ext import commands
 
 if TYPE_CHECKING:
@@ -205,7 +205,7 @@ async def response(
         if ctx.message.author.top_role >= ctx.channel.guild.me.top_role:
             return
 
-        all_punishments = run_all_checks(config, ctx.message)
+        all_punishments = await run_all_checks(config, ctx.message)
 
         if len(all_punishments) == 0:
             return
@@ -455,7 +455,7 @@ def generate_automod_alert_embed(
 # All checks will return a list of AutoModPunishment, which may be nothing
 
 
-def run_all_checks(
+async def run_all_checks(
     config: munch.Munch, message: discord.Message
 ) -> list[AutoModPunishment]:
     """This runs all 4 checks on a given discord.Message
@@ -475,6 +475,7 @@ def run_all_checks(
         run_only_string_checks(config, message.clean_content)
         + handle_file_extensions(config, message.attachments)
         + handle_mentions(config, message)
+        + await handle_file_hashes(config, message.attachments)
     )
     return all_violations
 
@@ -528,6 +529,35 @@ def handle_file_extensions(
     return violations
 
 
+async def handle_file_hashes(
+    config: munch.Munch, attachments: list[discord.Attachment]
+) -> list[AutoModPunishment]:
+    """This checks a list of attachments for attachments that match the configured list of hashes
+
+    Args:
+        config (munch.Munch): The guild config to check with
+        attachments (list[discord.Attachment]): The list of attachments to search
+
+    Returns:
+        list[AutoModPunishment]: The automod violations that the given message violated
+    """
+    violations = []
+
+    for attachment in attachments:
+        file_hash = await auxiliary.get_attachment_hash(attachment)
+        if file_hash in config.extensions.automod.banned_file_hashes.value:
+            violations.append(
+                AutoModPunishment(
+                    f"{attachment.filename} matches a banned file hash",
+                    recommend_delete=True,
+                    recommend_warn=False,
+                    recommend_mute=3600,
+                )
+            )
+
+    return violations
+
+
 def handle_mentions(
     config: munch.Munch, message: discord.Message
 ) -> list[AutoModPunishment]:

techsupport_bot/functions/logger.py

@@ -8,7 +8,7 @@
 import discord
 import munch
 from botlogging import LogContext, LogLevel
-from core import cogs, extensionconfig
+from core import auxiliary, cogs, extensionconfig
 from discord.ext import commands
 
 if TYPE_CHECKING:
@@ -193,13 +193,13 @@ async def send_message(
     attachments.insert(0, await author.display_avatar.to_file(filename="avatar.png"))
 
     # Make and send the embed and files
-    embed = build_embed(
+    embed = await build_embed(
         message, author, src_channel, content_override, special_flags=special_flags
     )
     await dest_channel.send(embed=embed, files=attachments[:11])
 
 
-def build_embed(
+async def build_embed(
     message: discord.Message,
     author: discord.Member,
     src_channel: discord.abc.GuildChannel | discord.Thread,
@@ -266,6 +266,18 @@ def build_embed(
         value=", ".join(generate_role_list(author)),
     )
 
+    # Add file hashes, if relevant
+    file_hash_string = ""
+
+    if message.attachments:
+        parts = []
+        for attachment in message.attachments:
+            file_hash = await auxiliary.get_attachment_hash(attachment)
+            parts.append(f"{attachment.filename}: {file_hash}")
+
+        file_hash_string = ", ".join(parts)
+        embed.add_field(name="File Hashes", value=file_hash_string)
+
     # Flags
     if special_flags:
         embed.add_field(name="Flags", value=", ".join(special_flags))

techsupport_bot/functions/paste.py

@@ -116,7 +116,7 @@ async def response(
             "\n"
         ) > self.max_newlines(config.extensions.paste.length_limit.value):
             if "automod" in config.get("enabled_extensions", []):
-                automod_actions = automod.run_all_checks(config, ctx.message)
+                automod_actions = await automod.run_all_checks(config, ctx.message)
                 automod_final = automod.process_automod_violations(automod_actions)
                 if automod_final and automod_final.delete_message:
                     return