Address review/security findings in the 2.21.0 error-detail feature:
- Keepalive drain no longer erases the terminal detail: capture/clear is
skipped for STATUS_KEEPALIVE so the reason the peer just sent survives the
owed keepalive replies.
- Replace the capture path with a dedicated protocol_receive_error_detail:
the declared length is validated against MAX_ERROR_DETAIL_BYTES before any
allocation, over-cap bodies are drained through a fixed scratch buffer (so
the stream never desyncs), in-cap bodies read straight into the thread-local
detail buffer, and session->max_alloc is never raised. Lengths beyond
MAX_STRING_SIZE are treated as a fatal framing error.
- The detail body now honors the caller's deadline (timed/keepalive paths) and
polls the abort callback between drain chunks.
- Escape peer-controlled detail text with output_escape before logging it in
client_send.c and config.c.
- Clear io_error_detail in io_set_fds so a new connection on the same thread
cannot inherit a stale reason.
- Add unit tests for the keepalive-survival, over-cap drain, absurd-length
fatal framing, and deadline-clamped body read cases.
TapTap
334fc5b3e8