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| author | Jose M Perez <[email protected]> | 2021-10-05 18:21:03 +0200 |
|---|---|---|
| committer | Loïc Hoguin <[email protected]> | 2025-01-23 11:37:27 +0100 |
| commit | 8e02c78464c86d427c2bd0bb449d17e7876b9903 (patch) | |
| tree | cd314d11927d2a2e8d263c4c80efddbe4843c578 /src | |
| parent | e3fbd81fc97c234fd19b29f676593c27f26031d4 (diff) | |
| download | cowlib-8e02c78464c86d427c2bd0bb449d17e7876b9903.tar.gz cowlib-8e02c78464c86d427c2bd0bb449d17e7876b9903.tar.bz2 cowlib-8e02c78464c86d427c2bd0bb449d17e7876b9903.zip | |
Disable WS compression when only server sets client_max_window_bits
When the client does not provide the "client_max_window_bits" option,
the server must be able to handle a sliding window of up to 32,768 bytes.
When the server has configured a lower limit than the default, and the
client has not provided the parameter, compression must be disabled.
Co-authored-by: Ignacio Martínez <[email protected]>
Diffstat (limited to 'src')
| -rw-r--r-- | src/cow_ws.erl | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/src/cow_ws.erl b/src/cow_ws.erl index c3d0fe2..f31cd10 100644 --- a/src/cow_ws.erl +++ b/src/cow_ws.erl @@ -135,6 +135,13 @@ negotiate_permessage_deflate1(Params, Extensions, Opts) -> ignore; {#{client_max_window_bits := CB}, _} when CB > ClientMaxWindowBits -> ignore; + %% When the server requires a client_max_window_bits lower than the + %% default, but the client does not support the parameter (the client + %% didn't send the parameter), fail the negotiation. (RFC7692 7.1.2.2) + {Negotiated, _} when + not is_map_key(client_max_window_bits_set, Negotiated), + ClientMaxWindowBits < 15 -> + ignore; {Negotiated, RespParams2} -> %% We add the configured max window bits if necessary. RespParams = case Negotiated of @@ -167,12 +174,14 @@ negotiate_params([{<<"client_max_window_bits">>, Max}|Tail], Negotiated, RespPar error -> ignore; CB when CB =< CB0 -> - negotiate_params(Tail, Negotiated#{client_max_window_bits => CB}, + negotiate_params(Tail, Negotiated#{ + client_max_window_bits => CB, + client_max_window_bits_set => true}, [<<"; client_max_window_bits=">>, Max|RespParams]); %% When the client sends window bits larger than the server wants %% to use, we use what the server defined. _ -> - negotiate_params(Tail, Negotiated, + negotiate_params(Tail, Negotiated#{client_max_window_bits_set => true}, [<<"; client_max_window_bits=">>, integer_to_binary(CB0)|RespParams]) end; negotiate_params([{<<"server_max_window_bits">>, Max}|Tail], Negotiated, RespParams) -> |