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authorKirill Kinduk <[email protected]>2017-08-25 12:08:26 +0300
committerLoïc Hoguin <[email protected]>2018-03-28 16:58:02 +0200
commit4c34774b7eb787e37892399f2daddba68ec277e3 (patch)
tree8640e0950bb363acde6f87f1f7a2977d3185c852 /src/cowboy_websocket.erl
parent288deb5b88dd8e0aae57c9858d16c19ca9f186f9 (diff)
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Add max_frame_size option for websocket handlers
Option allows to limit a frame by size before decoding its payload. LH: I have added a test for when the limit is reached on a nofin fragmented frame (the last commit addressed that case but it had no test). I have fixed formatting and other, and changed the default value to infinity since it might otherwise be incompatible with existing code. I also added documentation and a bunch of other minor changes.
Diffstat (limited to 'src/cowboy_websocket.erl')
-rw-r--r--src/cowboy_websocket.erl22
1 files changed, 17 insertions, 5 deletions
diff --git a/src/cowboy_websocket.erl b/src/cowboy_websocket.erl
index 725d7ec..df2e1a5 100644
--- a/src/cowboy_websocket.erl
+++ b/src/cowboy_websocket.erl
@@ -57,6 +57,7 @@
-type opts() :: #{
compress => boolean(),
idle_timeout => timeout(),
+ max_frame_size => non_neg_integer() | infinity,
req_filter => fun((cowboy_req:req()) -> map())
}.
-export_type([opts/0]).
@@ -71,6 +72,7 @@
timeout = infinity :: timeout(),
timeout_ref = undefined :: undefined | reference(),
compress = false :: boolean(),
+ max_frame_size :: non_neg_integer() | infinity,
messages = undefined :: undefined | {atom(), atom(), atom()},
hibernate = false :: boolean(),
frag_state = undefined :: cow_ws:frag_state(),
@@ -95,12 +97,14 @@ upgrade(Req, Env, Handler, HandlerState) ->
%% @todo Error out if HTTP/2.
upgrade(Req0, Env, Handler, HandlerState, Opts) ->
Timeout = maps:get(idle_timeout, Opts, 60000),
+ MaxFrameSize = maps:get(max_frame_size, Opts, infinity),
Compress = maps:get(compress, Opts, false),
FilteredReq = case maps:get(req_filter, Opts, undefined) of
undefined -> maps:with([method, version, scheme, host, port, path, qs, peer], Req0);
FilterFun -> FilterFun(Req0)
end,
- State0 = #state{handler=Handler, timeout=Timeout, compress=Compress, req=FilteredReq},
+ State0 = #state{handler=Handler, timeout=Timeout, compress=Compress,
+ max_frame_size=MaxFrameSize, req=FilteredReq},
try websocket_upgrade(State0, Req0) of
{ok, State, Req} ->
websocket_handshake(State, Req, HandlerState, Env);
@@ -291,12 +295,15 @@ parse(State, HandlerState, PS=#ps_payload{buffer=Buffer}, Data) ->
parse_payload(State, HandlerState, PS#ps_payload{buffer= <<>>},
<<Buffer/binary, Data/binary>>).
-parse_header(State=#state{frag_state=FragState, extensions=Extensions}, HandlerState,
- ParseState=#ps_header{buffer=Data}) ->
+parse_header(State=#state{max_frame_size=MaxFrameSize,
+ frag_state=FragState, extensions=Extensions},
+ HandlerState, ParseState=#ps_header{buffer=Data}) ->
case cow_ws:parse_header(Data, Extensions, FragState) of
%% All frames sent from the client to the server are masked.
{_, _, _, _, undefined, _} ->
websocket_close(State, HandlerState, {error, badframe});
+ {_, _, _, Len, _, _} when Len > MaxFrameSize ->
+ websocket_close(State, HandlerState, {error, badsize});
{Type, FragState2, Rsv, Len, MaskKey, Rest} ->
parse_payload(State#state{frag_state=FragState2}, HandlerState,
#ps_payload{type=Type, len=Len, mask_key=MaskKey, rsv=Rsv}, Rest);
@@ -335,11 +342,14 @@ parse_payload(State=#state{frag_state=FragState, utf8_state=Incomplete, extensio
end.
dispatch_frame(State=#state{socket=Socket, transport=Transport,
- frag_state=FragState, frag_buffer=SoFar, extensions=Extensions},
- HandlerState, #ps_payload{type=Type0, unmasked=Payload0, close_code=CloseCode0},
+ max_frame_size=MaxFrameSize, frag_state=FragState,
+ frag_buffer=SoFar, extensions=Extensions}, HandlerState,
+ #ps_payload{type=Type0, unmasked=Payload0, close_code=CloseCode0},
RemainingData) ->
case cow_ws:make_frame(Type0, Payload0, CloseCode0, FragState) of
%% @todo Allow receiving fragments.
+ {fragment, _, _, Payload} when byte_size(Payload) + byte_size(SoFar) > MaxFrameSize ->
+ websocket_close(State, HandlerState, {error, badsize});
{fragment, nofin, _, Payload} ->
parse_header(State#state{frag_buffer= << SoFar/binary, Payload/binary >>},
HandlerState, #ps_header{buffer=RemainingData});
@@ -447,6 +457,8 @@ websocket_send_close(#state{socket=Socket, transport=Transport,
Transport:send(Socket, cow_ws:frame({close, 1002, <<>>}, Extensions));
{error, badencoding} ->
Transport:send(Socket, cow_ws:frame({close, 1007, <<>>}, Extensions));
+ {error, badsize} ->
+ Transport:send(Socket, cow_ws:frame({close, 1009, <<>>}, Extensions));
{crash, _, _} ->
Transport:send(Socket, cow_ws:frame({close, 1011, <<>>}, Extensions));
remote ->