Appropriately handle urllib3's InvalidHeader exception (#5914)

requests/adapters.py

@@ -19,6 +19,7 @@ from urllib3.util.retry import Retry
 from urllib3.exceptions import ClosedPoolError
 from urllib3.exceptions import ConnectTimeoutError
 from urllib3.exceptions import HTTPError as _HTTPError
+from urllib3.exceptions import InvalidHeader as _InvalidHeader
 from urllib3.exceptions import MaxRetryError
 from urllib3.exceptions import NewConnectionError
 from urllib3.exceptions import ProxyError as _ProxyError
@@ -37,7 +38,7 @@ from .structures import CaseInsensitiveDict
 from .cookies import extract_cookies_to_jar
 from .exceptions import (ConnectionError, ConnectTimeout, ReadTimeout, SSLError,
                          ProxyError, RetryError, InvalidSchema, InvalidProxyURL,
-                         InvalidURL)
+                         InvalidURL, InvalidHeader)
 from .auth import _basic_auth_str
 
 try:
@@ -527,6 +528,8 @@ class HTTPAdapter(BaseAdapter):
                 raise SSLError(e, request=request)
             elif isinstance(e, ReadTimeoutError):
                 raise ReadTimeout(e, request=request)
+            elif isinstance(e, _InvalidHeader):
+                raise InvalidHeader(e, request=request)
             else:
                 raise
 

tests/test_lowlevel.py

@@ -46,6 +46,32 @@ def test_chunked_encoding_error():
         close_server.set()  # release server block
 
 
+def test_conflicting_content_lengths():
+    """Ensure we correctly throw an InvalidHeader error if multiple
+    conflicting Content-Length headers are returned.
+    """
+
+    def multiple_content_length_response_handler(sock):
+        request_content = consume_socket_content(sock, timeout=0.5)
+
+        sock.send(b"HTTP/1.1 200 OK\r\n" +
+                  b"Content-Type: text/plain\r\n" +
+                  b"Content-Length: 16\r\n" +
+                  b"Content-Length: 32\r\n\r\n" +
+                  b"-- Bad Actor -- Original Content\r\n")
+
+        return request_content
+
+    close_server = threading.Event()
+    server = Server(multiple_content_length_response_handler)
+
+    with server as (host, port):
+        url = 'http://{}:{}/'.format(host, port)
+        with pytest.raises(requests.exceptions.InvalidHeader):
+            r = requests.get(url)
+        close_server.set()
+
+
 def test_digestauth_401_count_reset_on_redirect():
     """Ensure we correctly reset num_401_calls after a successful digest auth,
     followed by a 302 redirect to another digest auth prompt.