https://gitlab.synchro.net/main/sbbs/-/commit/7ecf0b07863637a1259ec7fc
Modified Files:
src/sbbs3/answer.cpp ftpsrvr.cpp js_system.cpp login.cpp mailsrvr.cpp services.cpp userdat.c userdat.h websrvr.cpp
Log Message:
Report a failed user lookup as an error, not as an unknown user

matchuser() and finduserstr() returned 0 both when no user matched and
when name.dat or user.tab could not be opened or read, and
find_login_id() passed that through. Every authenticating server then
treated a lookup that never ran as a bad login: it logged "UNKNOWN
USER" (with the password when Echo Password is on), counted a failed
attempt against the client, and at the filter threshold banned its IP.
The SMTP recipient lookup bounced mail with a permanent 550 the same
way. A short read of name.dat returned a bogus user number.

The scanning bodies are now matchuser_ex() and finduserstr_ex(), which
return a USER_* error code when the user base could not be searched; matchuser() and finduserstr() clamp that to 0 so their other callers
and system.matchuser() are unchanged. find_login_id() propagates the
error, and system.find_login_id() clamps it for scripts. The login
paths in the mail, FTP, web, Services and terminal servers log the
error at LOG_ERR and answer with a temporary failure (-ERR [SYS/TEMP],
454 4.7.0, 451 4.3.0, 421) without calling badlogin(); the SSH path no
longer starts new-user registration on one.

Seen on vert on 2026-10-27 when a handle leak (c42d0dc07c) exhausted
the process's stdio streams: for four hours every real login was
reported as an unknown user and a mail client retrying a valid
account was banned for 90 days. Closes #1307.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

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