Issue #26586: Merge excessive HTTP header handling from 3.5

2 files changed, 14 insertions, 0 deletions

diff --git a/Lib/http/server.py b/Lib/http/server.py
index 5e91826..de6b531 100644
--- a/Lib/http/server.py
+++ b/Lib/http/server.py
@@ -338,6 +338,13 @@ class BaseHTTPRequestHandler(socketserver.StreamRequestHandler):
                 HTTPStatus.BAD_REQUEST,
                 "Line too long")
             return False
+        except http.client.HTTPException as err:
+            self.send_error(
+                HTTPStatus.REQUEST_HEADER_FIELDS_TOO_LARGE,
+                "Too many headers",
+                str(err)
+            )
+            return False
 
         conntype = self.headers.get('Connection', "")
         if conntype.lower() == 'close':
diff --git a/Lib/test/test_httpservers.py b/Lib/test/test_httpservers.py
index 5d44825..98798ae 100644
--- a/Lib/test/test_httpservers.py
+++ b/Lib/test/test_httpservers.py
@@ -859,6 +859,13 @@ class BaseHTTPRequestHandlerTestCase(unittest.TestCase):
         self.assertFalse(self.handler.get_called)
         self.assertEqual(self.handler.requestline, 'GET / HTTP/1.1')
 
+    def test_too_many_headers(self):
+        result = self.send_typical_request(
+            b'GET / HTTP/1.1\r\n' + b'X-Foo: bar\r\n' * 101 + b'\r\n')
+        self.assertEqual(result[0], b'HTTP/1.1 431 Too many headers\r\n')
+        self.assertFalse(self.handler.get_called)
+        self.assertEqual(self.handler.requestline, 'GET / HTTP/1.1')
+
     def test_close_connection(self):
         # handle_one_request() should be repeatedly called until
         # it sets close_connection