Fix byte-by-byte Websocket handling

If the websocket frame handling code in cowboy_http_websocket receives
only 1 byte at a time, it fails with a badmatch in
cowboy_http_websocket:websocket_data/4. This commit fixes the problem
and introduces a test of the correct behaviour.

2 files changed, 75 insertions, 7 deletions

diff --git a/src/cowboy_http_websocket.erl b/src/cowboy_http_websocket.erl
index 1164684..e481d4b 100644
--- a/src/cowboy_http_websocket.erl
+++ b/src/cowboy_http_websocket.erl
@@ -232,20 +232,26 @@ websocket_data(State=#state{version=0, eop=EOP}, Req, HandlerState,
 			%% @todo We probably should allow limiting frame length.
 			handler_before_loop(State, Req, HandlerState, Data)
 	end;
+%% incomplete hybi data frame.
+websocket_data(State=#state{version=Version}, Req, HandlerState, Data)
+		when Version =/= 0, byte_size(Data) =:= 1 ->
+	handler_before_loop(State, Req, HandlerState, Data);
 %% hybi data frame.
 %% @todo Handle Fin.
 websocket_data(State=#state{version=Version}, Req, HandlerState, Data)
 		when Version =/= 0 ->
 	<< 1:1, 0:3, Opcode:4, Mask:1, PayloadLen:7, Rest/bits >> = Data,
-	{PayloadLen2, Rest2} = case PayloadLen of
-		126 -> << L:16, R/bits >> = Rest, {L, R};
-		127 -> << 0:1, L:63, R/bits >> = Rest, {L, R};
-		PayloadLen -> {PayloadLen, Rest}
+	{PayloadLen2, Rest2} = case {PayloadLen, Rest} of
+		{126, << L:16, R/bits >>}  -> {L, R};
+		{126, Rest} -> {undefined, Rest};
+		{127, << 0:1, L:63, R/bits >>} -> {L, R};
+		{127, Rest} -> {undefined, Rest};
+		{PayloadLen, Rest} -> {PayloadLen, Rest}
 	end,
 	case {Mask, PayloadLen2} of
 		{0, 0} ->
 			websocket_dispatch(State, Req, HandlerState, Rest2, Opcode, <<>>);
-		{1, N} when N + 4 < byte_size(Rest2) ->
+		{1, N} when N + 4 > byte_size(Rest2); N =:= undefined ->
 			%% @todo We probably should allow limiting frame length.
 			handler_before_loop(State, Req, HandlerState, Data);
 		{1, _N} ->
diff --git a/test/http_SUITE.erl b/test/http_SUITE.erl
index 813aa15..2208256 100644
--- a/test/http_SUITE.erl
+++ b/test/http_SUITE.erl
@@ -20,7 +20,8 @@
 	init_per_group/2, end_per_group/2]). %% ct.
 -export([chunked_response/1, headers_dupe/1, headers_huge/1,
 	keepalive_nl/1, nc_rand/1, pipeline/1, raw/1,
-	ws0/1, ws8/1, ws_timeout_hibernate/1]). %% http.
+	ws0/1, ws8/1, ws8_single_bytes/1,
+	ws_timeout_hibernate/1]). %% http.
 -export([http_200/1, http_404/1]). %% http and https.
 -export([http_10_hostless/1]). %% misc.
 
@@ -33,7 +34,8 @@ groups() ->
 	BaseTests = [http_200, http_404],
 	[{http, [], [chunked_response, headers_dupe, headers_huge,
 		keepalive_nl, nc_rand, pipeline, raw,
-		ws0, ws8, ws_timeout_hibernate] ++ BaseTests},
+		ws0, ws8, ws8_single_bytes,
+		ws_timeout_hibernate] ++ BaseTests},
 	{https, [], BaseTests}, {misc, [], [http_10_hostless]}].
 
 init_per_suite(Config) ->
@@ -300,6 +302,66 @@ ws8(Config) ->
 	{error, closed} = gen_tcp:recv(Socket, 0, 6000),
 	ok.
 
+ws8_single_bytes(Config) ->
+	{port, Port} = lists:keyfind(port, 1, Config),
+	{ok, Socket} = gen_tcp:connect("localhost", Port,
+		[binary, {active, false}, {packet, raw}]),
+	ok = gen_tcp:send(Socket, [
+		"GET /websocket HTTP/1.1\r\n"
+		"Host: localhost\r\n"
+		"Connection: Upgrade\r\n"
+		"Upgrade: websocket\r\n"
+		"Sec-WebSocket-Origin: http://localhost\r\n"
+		"Sec-WebSocket-Version: 8\r\n"
+		"Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==\r\n"
+		"\r\n"]),
+	{ok, Handshake} = gen_tcp:recv(Socket, 0, 6000),
+	{ok, {http_response, {1, 1}, 101, "Switching Protocols"}, Rest}
+		= erlang:decode_packet(http, Handshake, []),
+	[Headers, <<>>] = websocket_headers(
+		erlang:decode_packet(httph, Rest, []), []),
+	{'Connection', "Upgrade"} = lists:keyfind('Connection', 1, Headers),
+	{'Upgrade', "websocket"} = lists:keyfind('Upgrade', 1, Headers),
+	{"sec-websocket-accept", "s3pPLMBiTxaQ9kYGzzhZRbK+xOo="}
+		= lists:keyfind("sec-websocket-accept", 1, Headers),
+	ok = gen_tcp:send(Socket, << 16#81 >>), %% send one byte
+	ok = timer:sleep(100), %% sleep for a period
+	ok = gen_tcp:send(Socket, << 16#85 >>), %% send another and so on
+        ok = timer:sleep(100),
+	ok = gen_tcp:send(Socket, << 16#37 >>),
+	ok = timer:sleep(100),
+	ok = gen_tcp:send(Socket, << 16#fa >>),
+	ok = timer:sleep(100),
+	ok = gen_tcp:send(Socket, << 16#21 >>),
+	ok = timer:sleep(100),
+	ok = gen_tcp:send(Socket, << 16#3d >>),
+	ok = timer:sleep(100),
+	ok = gen_tcp:send(Socket, << 16#7f >>),
+	ok = timer:sleep(100),
+	ok = gen_tcp:send(Socket, << 16#9f >>),
+	ok = timer:sleep(100),
+	ok = gen_tcp:send(Socket, << 16#4d >>),
+	ok = timer:sleep(100),
+	ok = gen_tcp:send(Socket, << 16#51 >>),
+	ok = timer:sleep(100),
+	ok = gen_tcp:send(Socket, << 16#58 >>),
+	{ok, << 1:1, 0:3, 1:4, 0:1, 14:7, "websocket_init" >>}
+		= gen_tcp:recv(Socket, 0, 6000),
+	{ok, << 1:1, 0:3, 1:4, 0:1, 5:7, "Hello" >>}
+		= gen_tcp:recv(Socket, 0, 6000),
+	{ok, << 1:1, 0:3, 1:4, 0:1, 16:7, "websocket_handle" >>}
+		= gen_tcp:recv(Socket, 0, 6000),
+	{ok, << 1:1, 0:3, 1:4, 0:1, 16:7, "websocket_handle" >>}
+		= gen_tcp:recv(Socket, 0, 6000),
+	{ok, << 1:1, 0:3, 1:4, 0:1, 16:7, "websocket_handle" >>}
+		= gen_tcp:recv(Socket, 0, 6000),
+	ok = gen_tcp:send(Socket, << 1:1, 0:3, 9:4, 0:8 >>), %% ping
+	{ok, << 1:1, 0:3, 10:4, 0:8 >>} = gen_tcp:recv(Socket, 0, 6000), %% pong
+	ok = gen_tcp:send(Socket, << 1:1, 0:3, 8:4, 0:8 >>), %% close
+	{ok, << 1:1, 0:3, 8:4, 0:8 >>} = gen_tcp:recv(Socket, 0, 6000),
+	{error, closed} = gen_tcp:recv(Socket, 0, 6000),
+	ok.
+
 ws_timeout_hibernate(Config) ->
 	{port, Port} = lists:keyfind(port, 1, Config),
 	{ok, Socket} = gen_tcp:connect("localhost", Port,