Improve HTTPS-on-HTTP parser error

CHANGES/10142.bugfix.rst

@@ -0,0 +1 @@
+Improved the parser error message shown when TLS handshake bytes are received on an HTTP port -- by :user:`puneetdixit200`.

CONTRIBUTORS.txt

@@ -316,6 +316,7 @@ Phebe Polk
 Philipp A.
 Pierre-Louis Peeters
 Pieter van Beek
+Puneet Dixit
 Qiao Han
 Rafael Viotti
 Rahul Nahata

aiohttp/_http_parser.pyx

@@ -21,6 +21,7 @@ from aiohttp.helpers import DEBUG, set_exception
 
 from .helpers import HeadersDictProxy as _HeadersDictProxy
 from .http_exceptions import (
+    HTTPS_ON_HTTP_PORT_ERROR,
     BadHttpMessage,
     BadHttpMethod,
     BadStatusLine,
@@ -932,6 +933,8 @@ cdef parser_error_from_errno(cparser.llhttp_t* parser, data, pointer):
                  cparser.HPE_INVALID_TRANSFER_ENCODING}:
         return BadHttpMessage(err_msg)
     elif errno == cparser.HPE_INVALID_METHOD:
+        if data.startswith(b"\x16\x03"):
+            return BadHttpMethod(error=HTTPS_ON_HTTP_PORT_ERROR)
         return BadHttpMethod(error=err_msg)
     elif errno in {cparser.HPE_INVALID_STATUS,
                    cparser.HPE_INVALID_VERSION,

aiohttp/http_exceptions.py

@@ -94,10 +94,15 @@ def __init__(self, line: str = "", error: str | None = None) -> None:
         self.line = line
 
 
+HTTPS_ON_HTTP_PORT_ERROR = "Received HTTPS traffic on an HTTP port"
+
+
 class BadHttpMethod(BadStatusLine):
     """Invalid HTTP method in status line."""
 
     def __init__(self, line: str = "", error: str | None = None) -> None:
+        if error is None and line.startswith("\x16\x03"):
+            error = HTTPS_ON_HTTP_PORT_ERROR
         super().__init__(line, error or f"Bad HTTP method in status line {line!r}")
 
 

tests/test_http_parser.py

@@ -1600,6 +1600,15 @@ def test_http_request_parser_bad_method(
         )
 
 
+def test_http_request_parser_tls_handshake_on_http_port(
+    parser: HttpRequestParser,
+) -> None:
+    with pytest.raises(http_exceptions.BadHttpMethod) as ctx:
+        parser.feed_data(b"\x16\x03\x03\x01F\x01\r\n\r\n")
+
+    assert "Received HTTPS traffic on an HTTP port" in str(ctx.value)
+
+
 def test_http_request_parser_bad_version(parser: HttpRequestParser) -> None:
     with pytest.raises(http_exceptions.BadHttpMessage):
         parser.feed_data(b"GET //get HT/11\r\nHost: a\r\n\r\n")