Fixed #35440 -- Simplified parse_header_parameters by leveraging stdlid's Message.

The `parse_header_parameters` function historically used Python's `cgi`
module  (now deprecated). In 34e2148fc725e7200050f74130d7523e3cd8507a,
the logic was inlined to work around this deprecation ( #33173). Later,
in d4d5427571b4bf3a21c902276c2a00215c2a37cc, the header parsing logic
was further cleaned up to align with `multipartparser.py` (#33697).

This change takes it a step further by replacing the copied `cgi` logic with
Python's `email.message.Message` API for a more robust and maintainable header
parsing implementation.

Thanks to Raphael Gaschignard for testing, and to Adam Johnson and Shai
Berger for reviews.

Co-authored-by: Ben Cail <bcail@crossway.org>
Co-authored-by: Natalia <124304+nessita@users.noreply.github.com>

1 files changed, 44 insertions, 1 deletions

diff --git a/tests/utils_tests/test_http.py b/tests/utils_tests/test_http.py
index d18fb63c0c..3730c2fcf5 100644
--- a/tests/utils_tests/test_http.py
+++ b/tests/utils_tests/test_http.py
@@ -6,6 +6,7 @@ from unittest import mock
 from django.test import SimpleTestCase
 from django.utils.datastructures import MultiValueDict
 from django.utils.http import (
+    MAX_HEADER_LENGTH,
     base36_to_int,
     content_disposition_header,
     escape_leading_slashes,
@@ -424,6 +425,8 @@ class EscapeLeadingSlashesTests(unittest.TestCase):
 class ParseHeaderParameterTests(unittest.TestCase):
     def test_basic(self):
         tests = [
+            ("", ("", {})),
+            (None, ("none", {})),
             ("text/plain", ("text/plain", {})),
             ("text/vnd.just.made.this.up ; ", ("text/vnd.just.made.this.up", {})),
             ("text/plain;charset=us-ascii", ("text/plain", {"charset": "us-ascii"})),
@@ -448,9 +451,17 @@ class ParseHeaderParameterTests(unittest.TestCase):
                 ("attachment", {"filename": "strange;name", "size": "123"}),
             ),
             (
+                'attachment; filename="strange;name";;;;size=123;;;',
+                ("attachment", {"filename": "strange;name", "size": "123"}),
+            ),
+            (
                 'form-data; name="files"; filename="fo\\"o;bar"',
                 ("form-data", {"name": "files", "filename": 'fo"o;bar'}),
             ),
+            (
+                'form-data; name="files"; filename="\\"fo\\"o;b\\\\ar\\""',
+                ("form-data", {"name": "files", "filename": '"fo"o;b\\ar"'}),
+            ),
         ]
         for header, expected in tests:
             with self.subTest(header=header):
@@ -480,12 +491,13 @@ class ParseHeaderParameterTests(unittest.TestCase):
         """
         Test wrongly formatted RFC 2231 headers (missing double single quotes).
         Parsing should not crash (#24209).
+        But stdlib email still decodes (#35440).
         """
         test_data = (
             (
                 "Content-Type: application/x-stuff; "
                 "title*='This%20is%20%2A%2A%2Afun%2A%2A%2A",
-                "'This%20is%20%2A%2A%2Afun%2A%2A%2A",
+                "'This is ***fun***",
             ),
             ("Content-Type: application/x-stuff; title*='foo.html", "'foo.html"),
             ("Content-Type: application/x-stuff; title*=bar.html", "bar.html"),
@@ -494,6 +506,37 @@ class ParseHeaderParameterTests(unittest.TestCase):
             parsed = parse_header_parameters(raw_line)
             self.assertEqual(parsed[1]["title"], expected_title)
 
+    def test_header_max_length(self):
+        base_header = "Content-Type: application/x-stuff; title*="
+        base_header_len = len(base_header)
+
+        test_data = [
+            (MAX_HEADER_LENGTH, {}),
+            (MAX_HEADER_LENGTH, {"max_length": None}),
+            (MAX_HEADER_LENGTH + 1, {"max_length": None}),
+            (100, {"max_length": 100}),
+        ]
+        for line_length, kwargs in test_data:
+            with self.subTest(line_length=line_length, kwargs=kwargs):
+                title = "x" * (line_length - base_header_len)
+                line = base_header + title
+                assert len(line) == line_length
+
+                parsed = parse_header_parameters(line, **kwargs)
+
+                expected = ("content-type: application/x-stuff", {"title": title})
+                self.assertEqual(parsed, expected)
+
+    def test_header_too_long(self):
+        test_data = [
+            ("x" * (MAX_HEADER_LENGTH + 1), {}),
+            ("x" * 101, {"max_length": 100}),
+        ]
+        for line, kwargs in test_data:
+            with self.subTest(line_length=len(line), kwargs=kwargs):
+                with self.assertRaises(ValueError):
+                    parse_header_parameters(line, **kwargs)
+
 
 class ContentDispositionHeaderTests(unittest.TestCase):
     def test_basic(self):