From a49200eef5681a21b47b9398804021b340486db8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Lo=C3=AFc=20Hoguin?= <essen@ninenines.eu>
Date: Wed, 26 Sep 2018 16:05:52 +0200
Subject: Don't crash on HEADERS frames with PRIORITY flag set

---
 src/gun_http2.erl      |  10 ++---
 test/rfc7540_SUITE.erl | 100 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 105 insertions(+), 5 deletions(-)
 create mode 100644 test/rfc7540_SUITE.erl

diff --git a/src/gun_http2.erl b/src/gun_http2.erl
index edbc7c0..6176fe3 100644
--- a/src/gun_http2.erl
+++ b/src/gun_http2.erl
@@ -188,11 +188,11 @@ frame({headers, StreamID, IsFin, head_fin, HeaderBlock},
 %% @todo HEADERS frame starting a headers block. Enter continuation mode.
 %frame(State, {headers, StreamID, IsFin, head_nofin, HeaderBlockFragment}) ->
 %	State#http2_state{parse_state={continuation, StreamID, IsFin, HeaderBlockFragment}};
-%% @todo Single HEADERS frame headers block with priority.
-%frame(State, {headers, StreamID, IsFin, head_fin,
-%		_IsExclusive, _DepStreamID, _Weight, HeaderBlock}) ->
-%	%% @todo Handle priority.
-%	stream_init(State, StreamID, IsFin, HeaderBlock);
+%% Single HEADERS frame headers block with priority.
+frame({headers, StreamID, IsFin, head_fin,
+		_IsExclusive, _DepStreamID, _Weight, HeaderBlock}, State) ->
+	%% @todo Handle priority.
+	frame({headers, StreamID, IsFin, head_fin, HeaderBlock}, State);
 %% @todo HEADERS frame starting a headers block. Enter continuation mode.
 %frame(State, {headers, StreamID, IsFin, head_nofin,
 %		_IsExclusive, _DepStreamID, _Weight, HeaderBlockFragment}) ->
diff --git a/test/rfc7540_SUITE.erl b/test/rfc7540_SUITE.erl
new file mode 100644
index 0000000..10084da
--- /dev/null
+++ b/test/rfc7540_SUITE.erl
@@ -0,0 +1,100 @@
+%% Copyright (c) 2018, Loïc Hoguin <essen@ninenines.eu>
+%%
+%% Permission to use, copy, modify, and/or distribute this software for any
+%% purpose with or without fee is hereby granted, provided that the above
+%% copyright notice and this permission notice appear in all copies.
+%%
+%% THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+%% WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+%% MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+%% ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+%% WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+%% ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+%% OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+-module(rfc7540_SUITE).
+-compile(export_all).
+-compile(nowarn_export_all).
+
+-import(ct_helper, [doc/1]).
+
+all() ->
+	ct_helper:all(?MODULE).
+
+%% Server helpers.
+
+do_origin_start(Fun) ->
+	Self = self(),
+	Pid = spawn_link(fun() -> do_origin_init_tcp(Self, Fun) end),
+	Port = do_receive(Pid),
+	{ok, Pid, Port}.
+
+do_origin_init_tcp(Parent, Fun) ->
+	{ok, ListenSocket} = gen_tcp:listen(0, [binary, {active, false}]),
+	{ok, {_, Port}} = inet:sockname(ListenSocket),
+	Parent ! {self(), Port},
+	{ok, ClientSocket} = gen_tcp:accept(ListenSocket, 5000),
+	do_handshake(ClientSocket, gen_tcp),
+	Fun(Parent, ClientSocket, gen_tcp).
+
+do_handshake(Socket, Transport) ->
+	%% Send a valid preface.
+	ok = Transport:send(Socket, cow_http2:settings(#{})),
+	%% Receive the fixed sequence from the preface.
+	Preface = <<"PRI * HTTP/2.0\r\n\r\nSM\r\n\r\n">>,
+	{ok, Preface} = Transport:recv(Socket, byte_size(Preface), 5000),
+	%% Receive the SETTINGS from the preface.
+	{ok, <<Len:24>>} = Transport:recv(Socket, 3, 1000),
+	{ok, <<4:8, 0:40, _:Len/binary>>} = Transport:recv(Socket, 6 + Len, 1000),
+	%% Send the SETTINGS ack.
+	ok = Transport:send(Socket, cow_http2:settings_ack()),
+	%% Receive the SETTINGS ack.
+	{ok, <<0:24, 4:8, 1:8, 0:32>>} = Transport:recv(Socket, 9, 1000),
+	ok.
+
+do_receive(Pid) ->
+	do_receive(Pid, 1000).
+
+do_receive(Pid, Timeout) ->
+	receive
+		{Pid, Msg} ->
+			Msg
+	after Timeout ->
+		error(timeout)
+	end.
+
+%% Tests.
+
+headers_priority_flag(_) ->
+	doc("HEADERS frames may include a PRIORITY flag indicating "
+		"that stream dependency information is attached. (RFC7540 6.2)"),
+	{ok, _, Port} = do_origin_start(fun(_, Socket, Transport) ->
+		%% Receive a HEADERS frame.
+		{ok, <<_:24, 1:8, _:8, 1:32>>} = Transport:recv(Socket, 9, 1000),
+		%% Send a HEADERS frame with PRIORITY back.
+		{HeadersBlock, _} = cow_hpack:encode([
+			{<<":status">>, <<"200">>}
+		]),
+		Len = iolist_size(HeadersBlock) + 5,
+		ok = Transport:send(Socket, [
+			<<Len:24, 1:8,
+				0:2, %% Undefined.
+				1:1, %% PRIORITY.
+				0:1, %% Undefined.
+				0:1, %% PADDED.
+				1:1, %% END_HEADERS.
+				0:1, %% Undefined.
+				1:1, %% END_STREAM.
+				0:1, 1:31,
+				1:1, %% Exclusive?
+				3:31, %% Stream dependency.
+				42:8 >>, %% Weight.
+			HeadersBlock
+		]),
+		timer:sleep(1000)
+	end),
+	{ok, ConnPid} = gun:open("localhost", Port, #{protocols => [http2]}),
+	{ok, http2} = gun:await_up(ConnPid),
+	StreamRef = gun:get(ConnPid, "/"),
+	{response, fin, 200, _} = gun:await(ConnPid, StreamRef),
+	gun:close(ConnPid).
-- 
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