https://gitlab.synchro.net/main/sbbs/-/commit/9a9a81ea0a4c6a5666ca5ae0
Modified Files:
src/syncterm/telnet_io.c
Log Message:
Fix telnet binary mode tracking.

When SyncTERM started by enabling binary mode in both directions,
the internal tracking of the binary status wasn't updated, so it
was incorrectly tracked as being in NVT mode. After a file
transfer, it would then revert to the NVT mode it throught it was
in.

This change updates the binary mode value when sending as well as
receiving TELNET_BINARY_TX.

This is still technically broken though since binary mode is
negotiated separately in each direction, and the initial send of
WILL + DO is actually a pair of requests that need to be confirmed
by the remote. Until they are confirmed, the connection is still
in NVT mode.

Hopefully though this isn't an issue since the remote should reply
to both, and if it denies there's no effective difference between
what we should do when already in binary mode and not because we
don't support any other modes (such as CHARSET option). Fixing it
correctly would get very complex and involve blocking the connection
until we get a response.
--- SBBSecho 3.24-Linux
* Origin: Vertrauen - [vert/cvs/bbs].synchro.net (1:103/705)

https://gitlab.synchro.net/main/sbbs/-/commit/6986bd4168837eed5e5593a2
Modified Files:
src/syncterm/telnet_io.c
Log Message:
Fix telnet parser getting stuck on long subnegotiations

telnet_interpret() stores incoming subnegotiation bytes in
telnet_cmd[64]. When the buffer fills, telnet_cmdlen stays at 64
and no further bytes are stored. The IAC SE termination check at telnet_cmd[telnet_cmdlen-2] then reads stale data and can never
match, so the parser permanently stays in SB mode and swallows all
subsequent terminal output.

Fix: when the buffer is full, slide the last two bytes forward so
that position [62] always holds the previous byte and [63] holds the
current byte. The existing telnet_cmd[telnet_cmdlen-2] check then
sees a fresh IAC when it arrives, and correctly terminates the
subnegotiation.

A malicious (or just chatty) server sending e.g. a >64-byte
ENVIRON or NEW-ENVIRON SB would trigger this.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
--- SBBSecho 3.37-Linux
* Origin: Vertrauen - [vert/cvs/bbs].synchro.net (1:103/705)