Fixed #36991 -- Raised BadRequest for invalid encodings in Content-Type headers.

Author: DineshThumma9

django/http/request.py

@@ -155,9 +155,12 @@ def accepts(self, media_type):
 
     def _set_content_type_params(self, meta):
         """Set content_type, content_params, and encoding."""
-        self.content_type, self.content_params = parse_header_parameters(
-            meta.get("CONTENT_TYPE", "")
-        )
+        try:
+            self.content_type, self.content_params = parse_header_parameters(
+                meta.get("CONTENT_TYPE", "")
+            )
+        except ValueError as exc:
+            raise BadRequest("Invalid Content-Type header.") from exc
         if "charset" in self.content_params:
             try:
                 codecs.lookup(self.content_params["charset"])

django/utils/http.py

@@ -366,7 +366,11 @@ def parse_header_parameters(line, max_length=MAX_HEADER_LENGTH):
                 value = value.replace("\\\\", "\\").replace('\\"', '"')
             if has_encoding:
                 encoding, lang, value = value.split("'")
-                value = unquote(value, encoding=encoding)
+                try:
+                    value = unquote(value, encoding=encoding)
+                except (LookupError, UnicodeDecodeError):
+                    msg = f"Invalid encoding {encoding!r} for RFC 2231 param."
+                    raise ValueError(msg)
             pdict[name] = value
     return key, pdict
 

tests/requests_tests/tests.py

@@ -456,6 +456,20 @@ def test_body_after_POST_multipart_form_data(self):
         with self.assertRaises(RawPostDataException):
             request.body
 
+    def test_malformed_header(self):
+        tests = [
+            # Invalid encoding name with percent-encoded value
+            "text/plain; charset*=BOGUS''%20",
+            # Another invalid encoding with different value
+            "text/plain; filename*=INVALID''%s%s%s",
+            # Invalid encoding with multi-line encoded content
+            "text/plain; title*=NOTACODEC''%E2%80%A6",
+        ]
+        msg = "Invalid Content-Type header."
+        for header in tests:
+            with self.subTest(header=header), self.assertRaisesMessage(BadRequest, msg):
+                WSGIRequest({"REQUEST_METHOD": "GET", "CONTENT_TYPE": header})
+
     def test_malformed_multipart_header(self):
         tests = [
             ('Content-Disposition : form-data; name="name"', {"name": ["value"]}),

tests/utils_tests/test_http.py

@@ -521,6 +521,20 @@ def test_rfc2231_wrong_title(self):
             parsed = parse_header_parameters(raw_line)
             self.assertEqual(parsed[1]["title"], expected_title)
 
+    def test_rfc2231_invalid_encoding(self):
+        test_data = [
+            # Invalid encoding name with percent-encoded value
+            "text/plain; charset*=BOGUS''%20",
+            # Another invalid encoding with different value
+            "text/plain; filename*=INVALID''%s%s%s",
+            # Invalid encoding with multi-line encoded content
+            "text/plain; title*=NOTACODEC''%E2%80%A6",
+        ]
+        msg = "Invalid encoding"
+        for header in test_data:
+            with self.subTest(raw_line=header), self.assertRaisesRegex(ValueError, msg):
+                parse_header_parameters(header)
+
     def test_header_max_length(self):
         base_header = "Content-Type: application/x-stuff; title*="
         base_header_len = len(base_header)