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Receive and ignore HTTP/2 request trailers if any

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This is a first step toward properly supporting request trailers.
This commit is contained in:
Loïc Hoguin 2018-04-29 11:29:26 +02:00
parent 2db5ffbf84
commit 84b4128d06
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GPG key ID: 8A9DF795F6FED764
2 changed files with 192 additions and 22 deletions
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69
src/cowboy_http2.erl
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@ -420,14 +420,28 @@ frame(State0=#state{remote_window=ConnWindow, streams=Streams, lingering_streams
frame(State, {headers, StreamID, _, _, _}) when StreamID rem 2 =:= 0 ->
terminate(State, {connection_error, protocol_error,
'HEADERS frame received with even-numbered streamid. (RFC7540 5.1.1)'});
%% HEADERS frame received on (half-)closed stream.
%%
%% We always close the connection here to avoid having to decode
%% the headers to not waste resources on non-compliant clients.
frame(State=#state{client_streamid=LastStreamID}, {headers, StreamID, _, _, _})
%% Either a HEADERS frame received on (half-)closed stream,
%% or a HEADERS frame containing the trailers.
frame(State=#state{client_streamid=LastStreamID, streams=Streams},
{headers, StreamID, IsFin, IsHeadFin, HeaderBlockOrFragment})
when StreamID =< LastStreamID ->
terminate(State, {connection_error, stream_closed,
'HEADERS frame received on a stream in closed or half-closed state. (RFC7540 5.1)'});
case lists:keyfind(StreamID, #stream.id, Streams) of
Stream = #stream{remote=nofin} when IsFin =:= fin ->
case IsHeadFin of
head_fin ->
stream_decode_trailers(State, Stream, HeaderBlockOrFragment);
head_nofin ->
State#state{parse_state={continuation, StreamID, IsFin, HeaderBlockOrFragment}}
end;
%% We always close the connection here to avoid having to decode
%% the headers to not waste resources on non-compliant clients.
#stream{remote=nofin} when IsFin =:= nofin ->
terminate(State, {connection_error, protocol_error,
'Trailing HEADERS frame received without the END_STREAM flag set. (RFC7540 8.1, RFC7540 8.1.2.6)'});
_ ->
terminate(State, {connection_error, stream_closed,
'HEADERS frame received on a stream in closed or half-closed state. (RFC7540 5.1)'})
end;
%% Single HEADERS frame headers block.
frame(State, {headers, StreamID, IsFin, head_fin, HeaderBlock}) ->
%% @todo We probably need to validate StreamID here and in 4 next clauses.
@ -544,10 +558,17 @@ frame(State, {continuation, _, _, _}) ->
terminate(State, {connection_error, protocol_error,
'CONTINUATION frames MUST be preceded by a HEADERS frame. (RFC7540 6.10)'}).
continuation_frame(State=#state{parse_state={continuation, StreamID, IsFin, HeaderBlockFragment0}},
continuation_frame(State=#state{client_streamid=LastStreamID, streams=Streams,
parse_state={continuation, StreamID, IsFin, HeaderBlockFragment0}},
{continuation, StreamID, head_fin, HeaderBlockFragment1}) ->
stream_decode_init(State#state{parse_state=normal}, StreamID, IsFin,
<< HeaderBlockFragment0/binary, HeaderBlockFragment1/binary >>);
HeaderBlock = << HeaderBlockFragment0/binary, HeaderBlockFragment1/binary >>,
case StreamID > LastStreamID of
true -> %% New stream.
stream_decode_init(State#state{parse_state=normal}, StreamID, IsFin, HeaderBlock);
false -> %% Trailers.
Stream = lists:keyfind(StreamID, #stream.id, Streams),
stream_decode_trailers(State, Stream, HeaderBlock)
end;
continuation_frame(State=#state{parse_state={continuation, StreamID, IsFin, HeaderBlockFragment0}},
{continuation, StreamID, head_nofin, HeaderBlockFragment1}) ->
State#state{parse_state={continuation, StreamID, IsFin,
@ -1181,6 +1202,34 @@ stream_handler_init(State=#state{opts=Opts,
'Unhandled exception in cowboy_stream:init/3.'})
end.
stream_decode_trailers(State=#state{decode_state=DecodeState0}, Stream, HeaderBlock) ->
try cow_hpack:decode(HeaderBlock, DecodeState0) of
{Headers, DecodeState} ->
stream_reject_pseudo_headers_in_trailers(State#state{decode_state=DecodeState},
Stream#stream{remote=fin}, Headers)
catch _:_ ->
terminate(State, {connection_error, compression_error,
'Error while trying to decode HPACK-encoded header block. (RFC7540 4.3)'})
end.
stream_reject_pseudo_headers_in_trailers(State, Stream=#stream{id=StreamID}, Headers) ->
case has_pseudo_header(Headers) of
false ->
%% @todo There's probably a number of regular headers forbidden too.
%% @todo Propagate trailers.
after_commands(State, Stream);
true ->
stream_reset(State, StreamID, {stream_error, protocol_error,
'Trailer header blocks must not contain pseudo-headers. (RFC7540 8.1.2.1)'})
end.
has_pseudo_header([]) ->
false;
has_pseudo_header([{<<":", _/bits>>, _}|_]) ->
true;
has_pseudo_header([_|Tail]) ->
has_pseudo_header(Tail).
%% @todo Don't send an RST_STREAM if one was already sent.
stream_reset(State=#state{socket=Socket, transport=Transport}, StreamID, StreamError) ->
Reason = case StreamError of