From b594c5ceaca38e1ac215f916538fb128e3526a36 Mon Sep 17 00:00:00 2001
From: Illia Volochii <illia.volochii@gmail.com>
Date: Tue, 17 Oct 2023 19:35:39 +0300
Subject: [PATCH] Merge pull request from GHSA-g4mx-q9vg-27p4

Conflict:test/with_dummyserver/test_poolmanager.py and
test_connectionpool.py has not been modified because it has been deleted
in the pre-phase of the spec file
Reference:https://github.com/urllib3/urllib3/commit/b594c5ceaca38e1ac215f916538fb128e3526a36

---
 dummyserver/handlers.py       |  7 +++++++
 src/urllib3/_collections.py   | 18 ++++++++++++++++++
 src/urllib3/connectionpool.py |  6 +++++-
 src/urllib3/poolmanager.py    |  7 +++++--
 4 files changed, 35 insertions(+), 3 deletions(-)

diff --git a/dummyserver/handlers.py b/dummyserver/handlers.py
index 696dbab..6b501c7 100644
--- a/dummyserver/handlers.py
+++ b/dummyserver/handlers.py
@@ -182,6 +182,8 @@ class TestingApp(RequestHandler):
         status = request.params.get("status", "303 See Other")
         if len(status) == 3:
             status = "%s Redirect" % status.decode("latin-1")
+        elif isinstance(status, bytes):
+            status = status.decode("latin-1")
 
         headers = [("Location", target)]
         return Response(status=status, headers=headers)
@@ -260,6 +262,11 @@ class TestingApp(RequestHandler):
     def headers(self, request):
         return Response(json.dumps(dict(request.headers)))
 
+    def headers_and_params(self, request):
+        return Response(
+            json.dumps({"headers": dict(requests.headers), "params": request.params})
+        )
+
     def successful_retry(self, request):
         """ Handler which will return an error and then success
 
diff --git a/src/urllib3/_collections.py b/src/urllib3/_collections.py
index 019d151..8b3f0f7 100644
--- a/src/urllib3/_collections.py
+++ b/src/urllib3/_collections.py
@@ -267,6 +267,24 @@ class HTTPHeaderDict(MutableMapping):
         else:
             return vals[1:]
 
+    def _prepare_for_method_change(self):
+        """
+        Remove content-specific header fields before changing the request
+        method to GET or HEAD according to RFC 9110, Section 15.4.
+        """
+        content_specific_headers = [
+            "Content-Encoding",
+            "Content-Language",
+            "Content-Location",
+            "Content-Type",
+            "Content-Length",
+            "Digest",
+            "Last-Modified",
+        ]
+        for header in content_specific_headers:
+            self.discard(header)
+        return self
+
     # Backwards compatibility for httplib
     getheaders = getlist
     getallmatchingheaders = getlist
diff --git a/src/urllib3/connectionpool.py b/src/urllib3/connectionpool.py
index 174fe6c..40bf7f6 100644
--- a/src/urllib3/connectionpool.py
+++ b/src/urllib3/connectionpool.py
@@ -7,7 +7,7 @@ import warnings
 from socket import error as SocketError, timeout as SocketTimeout
 import socket
 
-
+from ._collections import HTTPHeaderDict
 from .exceptions import (
     ClosedPoolError,
     ProtocolError,
@@ -771,7 +771,11 @@ class HTTPConnectionPool(ConnectionPool, RequestMethods):
         redirect_location = redirect and response.get_redirect_location()
         if redirect_location:
             if response.status == 303:
+                # Change the method according to RFC 9110, Section 15.4.4.
                 method = "GET"
+                # And lose the body not to transfer anything sensitive
+                body = None
+                headers = HTTPHeaderDict(headers)._prepare_for_method_change()
 
             try:
                 retries = retries.increment(method, url, response=response, _pool=self)
diff --git a/src/urllib3/poolmanager.py b/src/urllib3/poolmanager.py
index a23ff11..e60197e 100644
--- a/src/urllib3/poolmanager.py
+++ b/src/urllib3/poolmanager.py
@@ -4,7 +4,7 @@ import functools
 import logging
 import warnings
 
-from ._collections import RecentlyUsedContainer
+from ._collections import HTTPHeaderDict, RecentlyUsedContainer
 from .connectionpool import HTTPConnectionPool, HTTPSConnectionPool
 from .connectionpool import port_by_scheme
 from .exceptions import (
@@ -343,9 +343,12 @@ class PoolManager(RequestMethods):
         # Support relative URLs for redirecting.
         redirect_location = urljoin(url, redirect_location)
 
-        # RFC 7231, Section 6.4.4
         if response.status == 303:
+            # Change the method according to RFC 9110, Section 15.4.4.
             method = "GET"
+            # And lose the body not to transfer anything sensitive.
+            kw["body"] = None
+            kw["headers"] = HTTPHeaderDict(kw["headers"])._prepare_for_method_change()
 
         retries = kw.get("retries")
         if not isinstance(retries, Retry):
-- 
2.23.0