fix(httpv2)!: frame Length counts the 9-octet header, so RFC 9113 frames are rejected

docs/source/pcapkit/protocols/application/httpv2.rst

@@ -12,7 +12,7 @@ below:
 ======= ========= ===================== ==========================
 Octets      Bits        Name                    Description
 ======= ========= ===================== ==========================
-  0           0   ``http.length``             Length
+  0           0   ``http.length``             Payload Length
   3          24   ``http.type``               Type
   4          32   ``http.flags``              Flags
   5          40                               Reserved

pcapkit/protocols/application/httpv2.py

@@ -13,7 +13,7 @@
 ======= ========= ===================== ==========================
 Octets      Bits        Name                    Description
 ======= ========= ===================== ==========================
-  0           0   ``http.length``             Length
+  0           0   ``http.length``             Payload Length
   3          24   ``http.type``               Type
   4          32   ``http.flags``              Flags
   5          40                               Reserved
@@ -290,12 +290,11 @@ def read(self, length: 'Optional[int]' = None, **kwargs: 'Any') -> 'Data_HTTP':
         # than it claims report a length nothing backs (e.g. a nine-octet buffer
         # declaring 16777215). ``length`` is the number of octets actually
         # available for this frame (``Protocol.__len__`` returns
-        # ``len(self._data)``, and an explicit ``length`` means the same), so
-        # both have to clear the minimum header size *and* the declared value
-        # must not exceed what is available. This library's convention (see
-        # ``_make_http_length``) is that ``length`` counts the whole frame,
-        # header included, so the two are directly comparable.
-        if schema.length < 9 or length < 9 or schema.length > length:
+        # ``len(self._data)``, and an explicit ``length`` means the same), so it
+        # has to clear the 9-octet header *and* back the declared value. The
+        # declared value counts the frame payload only, the header excluded
+        # (:rfc:`9113#section-4.1`), so ``length`` must hold both.
+        if length < 9 or schema.length + 9 > length:
             raise ProtocolError(f'HTTP/2: [Type {schema.type}] invalid format')
         if schema.type in (Enum_Frame.SETTINGS, Enum_Frame.PING) and schema.stream['sid'] != 0:
             raise ProtocolError(f'HTTP/2: [Type {schema.type}] invalid format')
@@ -364,7 +363,7 @@ def make(self,  # type: ignore[override]
         for bit in range(8):
             flags_val[f'bit_{bit}'] = (int(flags) & (1 << bit)) >> bit
 
-        length = self._make_http_length(frame_val, flags) + 9
+        length = self._make_http_length(frame_val, flags)
 
         return Schema_HTTP(
             length=length,
@@ -634,7 +633,7 @@ def _read_http_priority(self, schema: 'Schema_PriorityFrame', *,
             ProtocolError: If the packet is malformed.
 
         """
-        if header.length != 9:
+        if header.length != 5:
             raise ProtocolError(f'HTTP/2: [Type {header.type}] invalid format')
 
         data = Data_PriorityFrame(
@@ -677,7 +676,7 @@ def _read_http_rst_stream(self, schema: 'Schema_RSTStreamFrame', *,
             ProtocolError: If the packet is malformed.
 
         """
-        if header.length != 13:
+        if header.length != 4:
             raise ProtocolError(f'HTTP/2: [Type {header.type}] invalid format')
 
         data = Data_RSTStreamFrame(
@@ -721,7 +720,7 @@ def _read_http_settings(self, schema: 'Schema_SettingsFrame', *,
             ProtocolError: If the packet is malformed.
 
         """
-        if (header.length - 9) % 6 != 0 or header.stream['sid'] != 0:
+        if header.length % 6 != 0 or header.stream['sid'] != 0:
             raise ProtocolError(f'HTTP/2: [Type {header.type}] invalid format')
 
         flag = Data_SettingsFrameFlags(
@@ -731,7 +730,7 @@ def _read_http_settings(self, schema: 'Schema_SettingsFrame', *,
             '__value__': schema.__flags__,
         })
 
-        if flag.ACK and header.length - 9 != 0:
+        if flag.ACK and header.length != 0:
             raise ProtocolError(f'HTTP/2: [Type {header.type}] invalid format')
 
         sets = OrderedMultiDict()  # type: OrderedMultiDict[Enum_Setting, int]
@@ -782,7 +781,7 @@ def _read_http_push_promise(self, schema: 'Schema_PushPromiseFrame', *,
             ProtocolError: If the packet is malformed.
 
         """
-        if header.length < 13:
+        if header.length < 4:
             raise ProtocolError(f'HTTP/2: [Type {header.type}] invalid format')
 
         flag = Data_PushPromiseFrameFlags(
@@ -836,7 +835,7 @@ def _read_http_ping(self, schema: 'Schema_PingFrame', *,
             ProtocolError: If the packet is malformed.
 
         """
-        if header.length != 17:
+        if header.length != 8:
             raise ProtocolError(f'HTTP/2: [Type {header.type}] invalid format')
 
         flag = Data_PingFrameFlags(
@@ -925,7 +924,7 @@ def _read_http_window_update(self, schema: 'Schema_WindowUpdateFrame', *,
             ProtocolError: If the packet is malformed.
 
         """
-        if header.length != 13:
+        if header.length != 4:
             raise ProtocolError(f'HTTP/2: [Type {header.type}] invalid format')
 
         data = Data_WindowUpdateFrame(

pcapkit/protocols/data/application/httpv2.py

@@ -42,7 +42,7 @@ class Flags(Data):
 class HTTP(Protocol):
     """Data model for HTTP/2 protocol."""
 
-    #: Length.
+    #: Length of the frame payload, the 9-octet header excluded.
     length: 'int'
     #: Frame type.
     type: 'Frame'

pcapkit/protocols/schema/application/httpv2.py

@@ -88,7 +88,7 @@ def http_frame_selector(pkt: 'dict[str, Any]') -> 'Field':
 class HTTP(Schema):
     """Header schema for HTTP/2 packet."""
 
-    #: Length.
+    #: Length of the frame payload, the 9-octet header excluded.
     length: 'int' = NumberField(length=3, signed=False)
     #: Frame type.
     type: 'Enum_Frame' = EnumField(length=1, namespace=Enum_Frame)