fix(discord,gateway): inbound WS buffer overflow and WebChat drop - #81
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fix(discord,gateway): inbound WS buffer overflow and WebChat drop#81cursor[bot] wants to merge 2 commits into
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discord_rx_append grew only when cap < rx_len+len, then wrote a NUL at rx_len+len. Two 64KiB LWS fragments filled a doubled buffer exactly, so the terminator was one byte past the heap block (typical READY payloads). Co-authored-by: esadrianno <esadrianno@gmail.com>
…split LWS delivers at most rx_buffer_size bytes per RECEIVE. The ws protocol used 256 with no fragment reassembly, so dashboard messages over ~220 characters were parsed as incomplete JSON and dropped. Size the buffer to fit a full WebChat frame (MSG_MAX plus JSON envelope). Distinct from outbound #62. Co-authored-by: esadrianno <esadrianno@gmail.com>
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Summary
Two inbound WebSocket buffer bugs: Discord Gateway RX wrote a NUL one byte past the heap block, and dashboard WebChat silently dropped messages larger than one 256-byte LWS callback.
Bug 1 — Discord Gateway RX heap overflow (CRITICAL)
src/channels/discord.c(discord_rx_append, nowdiscord_helpers_rx_append)rx_buffer_size = 65536. First 64KiB fragment doubles the buffer to 131072 withrx_len = 65536. Second 64KiB fragment:rx_cap < rx_len + lenis false (131072 < 131072), grow is skipped, thenrx_buf[rx_len] = '\0'writes at index 131072 (one past the allocation). Typical Discord READY (or any DISPATCH) payload >128KiB, well underRX_MAX(512KiB).parse_response_bodyrealloc-before-success. fix(webchat): align WebSocket payload limit with agent response buffer #62 is WebChat outbound 8KiB vs 32KiB (ws_send_to/MSG_MAX), not Discord client RX. Telegram/OpenAI curl writers already include+1for NUL.Bug 2 — WebChat inbound frames not reassembled (HIGH)
src/gateway/http.cprotocols"ws".rx_buffer_size = 256;src/gateway/http_lws.cws_callbackLWS_CALLBACK_RECEIVE{"type":"message","text":"..."}). LWS splits at 256 bytes; each chunk iscJSON_Parsed as a complete object and fails; the user message is dropped.rx_buffer_sizeor fragment reassembly.Fix
cap < rx_len + chunk + 1(payload plus trailing NUL). Discard remaining fragments after overflow untillws_is_final_fragment.rx_buffer_sizetoWS_RX_BUFFER_SIZE(32KiB) so a full frame atMSG_MAXplus JSON envelope arrives in one RECEIVE.Validation
CI=true make test_discord_helpers(includes exact-fill 4095+1 and two 64KiB fragments)test_discord_helpersGATEWAY=1compile ofdiscord.c,http.c,http_lws.c