From ee2bcdec653edfc5316164f2a58bda64ed8b761f Mon Sep 17 00:00:00 2001
From: Mark Haines <mark.haines@matrix.org>
Date: Wed, 3 Sep 2014 17:04:00 +0100
Subject: [PATCH] Limit the size of uploads

---
 synapse/config/homeserver.py       |  3 ++-
 synapse/config/repository.py       | 39 ++++++++++++++++++++++++++++++
 synapse/http/content_repository.py | 14 +++++++++++
 3 files changed, 55 insertions(+), 1 deletion(-)
 create mode 100644 synapse/config/repository.py

diff --git a/synapse/config/homeserver.py b/synapse/config/homeserver.py
index a9aa4c735..1318a0eea 100644
--- a/synapse/config/homeserver.py
+++ b/synapse/config/homeserver.py
@@ -18,9 +18,10 @@ from .server import ServerConfig
 from .logger import LoggingConfig
 from .database import DatabaseConfig
 from .ratelimiting import RatelimitConfig
+from .repository import ContentRepositoryConfig
 
 class HomeServerConfig(TlsConfig, ServerConfig, DatabaseConfig, LoggingConfig,
-                       RatelimitConfig):
+                       RatelimitConfig, ContentRepositoryConfig):
     pass
 
 if __name__=='__main__':
diff --git a/synapse/config/repository.py b/synapse/config/repository.py
new file mode 100644
index 000000000..407c8d6c2
--- /dev/null
+++ b/synapse/config/repository.py
@@ -0,0 +1,39 @@
+# -*- coding: utf-8 -*-
+# Copyright 2014 matrix.org
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from ._base import Config
+import os
+
+class ContentRepositoryConfig(Config):
+    def __init__(self, args):
+        super(ContentRepositoryConfig, self).__init__(args)
+        self.max_upload_size = self.parse_size(args.max_upload_size)
+
+    def parse_size(self, string):
+        sizes = {"K": 1024, "M": 1024 * 1024}
+        size = 1
+        suffix = string[-1]
+        if suffix in sizes:
+            string = string[:-1]
+            size = sizes[suffix]
+        return int(string) * size
+
+    @classmethod
+    def add_arguments(cls, parser):
+        super(ContentRepositoryConfig, cls).add_arguments(parser)
+        db_group = parser.add_argument_group("content_repository")
+        db_group.add_argument(
+            "--max-upload-size", default="1M"
+        )
diff --git a/synapse/http/content_repository.py b/synapse/http/content_repository.py
index 5f5cd9b9e..6a80c5f2c 100644
--- a/synapse/http/content_repository.py
+++ b/synapse/http/content_repository.py
@@ -56,6 +56,7 @@ class ContentRepoResource(resource.Resource):
         self.directory = directory
         self.auth = auth
         self.external_addr = external_addr.rstrip('/')
+        self.max_upload_size = hs.config.max_upload_size
 
         if not os.path.isdir(self.directory):
             os.mkdir(self.directory)
@@ -155,6 +156,19 @@ class ContentRepoResource(resource.Resource):
     @defer.inlineCallbacks
     def _async_render(self, request):
         try:
+            # TODO: The checks here are a bit late. The content will have
+            # already been uploaded to a tmp file at this point
+            content_length = request.getHeader("Content-Length")
+            if content_length is None:
+                raise SynapseError(
+                    msg="Request must specify a Content-Length", code=400
+                )
+            if int(content_length) > self.max_upload_size:
+                raise SynapseError(
+                    msg="Upload request body is too large",
+                    code=413,
+                )
+
             fname = yield self.map_request_to_name(request)
 
             # TODO I have a suspcious feeling this is just going to block