Remove upper limit on max header size config (#1313)

Fixes #1306

gunicorn/config.py

@@ -793,8 +793,12 @@ class LimitRequestFieldSize(Setting):
     desc = """\
         Limit the allowed size of an HTTP request header field.
 
-        Value is a number from 0 (unlimited) to 8190. to set the limit
-        on the allowed size of an HTTP request header field.
+        Value is a positive number or 0. Setting it to 0 will allow unlimited
+        header field sizes.
+
+        .. warning::
+           Setting this parameter to a very high or unlimited value can open
+           up for DDOS attacks.
         """
 
 

gunicorn/http/message.py

@@ -19,7 +19,7 @@ from gunicorn._compat import urlsplit
 
 MAX_REQUEST_LINE = 8190
 MAX_HEADERS = 32768
-MAX_HEADERFIELD_SIZE = 8190
+DEFAULT_MAX_HEADERFIELD_SIZE = 8190
 
 HEADER_RE = re.compile("[\x00-\x1F\x7F()<>@,;:\[\]={} \t\\\\\"]")
 METH_RE = re.compile(r"[A-Z0-9$-_.]{3,20}")
@@ -41,12 +41,11 @@ class Message(object):
             or self.limit_request_fields > MAX_HEADERS):
             self.limit_request_fields = MAX_HEADERS
         self.limit_request_field_size = cfg.limit_request_field_size
-        if (self.limit_request_field_size < 0
-            or self.limit_request_field_size > MAX_HEADERFIELD_SIZE):
-            self.limit_request_field_size = MAX_HEADERFIELD_SIZE
+        if self.limit_request_field_size < 0:
+            self.limit_request_field_size = DEFAULT_MAX_HEADERFIELD_SIZE
 
         # set max header buffer size
-        max_header_field_size = self.limit_request_field_size or MAX_HEADERFIELD_SIZE
+        max_header_field_size = self.limit_request_field_size or DEFAULT_MAX_HEADERFIELD_SIZE
         self.max_buffer_headers = self.limit_request_fields * \
             (max_header_field_size + 2) + 4
 

tests/requests/invalid/017.py

@@ -0,0 +1,5 @@
+from gunicorn.config import Config
+from gunicorn.http.errors import LimitRequestHeaders
+
+cfg = Config()
+request = LimitRequestHeaders

tests/requests/valid/024.py

@@ -1,5 +1,4 @@
 from gunicorn.config import Config
-from gunicorn.http.errors import LimitRequestHeaders
 
 cfg = Config()
 cfg.set('limit_request_line', 0)