Dovecot submission panics on SMTP RCPT error

Hi,

If SMTP server rejects RCPT with message

aaa bbbbbbbbbb ccccccc dd eeeeeeeeeeee ffffffffffff gggggggggg hh iiiiii  jj kk llll   mmmmmmmmmm nnn o ppppppppppppppp rrrrrr ssssss t uuuu w xxxxxxx yyyyyy zzzzzzzz aa bbbbbbbbbbb cccccccc   dd eeeeee fff gggggg hhhhhhh iiiiiiii jj kkkkkk  ll mm nnnn  ooooo  ppppppp qqqq r ssss tttttt uuuuuuuuuuuuu www xxx yyyyyyy zzzzz aaaaa bbbbbbbbb ccc ddddddd

when submitting message via dovecot submisstion server, dovecot panics:

2023-08-10 17:10:04 myhost exim[...] rejected RCPT <[...]>: aa bbbbbbbbbb ccccccc dd eeeeeeeeeeee ffffffffffff gggggggggg hh iiiiii  jj kk llll   mmmmmmmmmm nnn o ppppppppppppppp rrrrrr ssssss t uuuu w xxxxxxx yyyyyy zzzzzzzz aa bbbbbbbbbbb cccccccc   dd eeeeee fff gggggg hhhhhhh iiiiiiii jj kkkkkk  ll mm nnnn  ooooo  ppppppp qqqq r ssss tttttt uuuuuuuuuuuuu www xxx yyyyyyy zzzzz aaaaa bbbbbbbbb ccc ddddddd

2023-08-10 17:10:04 myhost dovecot: submission(test)<7274>: Panic: file smtp-server-reply.c: line 625 (smtp_server_reply_send_real): assertion failed: (text[0] == '-')

2023-08-10 17:10:04 myhost dovecot: submission(test)<7274>: Error: Raw backtrace: /usr/lib/dovecot/libdovecot.so.0(backtrace_append+0x42) [0x7f64c8e484e2] -> /usr/lib/dovecot/libdovecot.so.0(backtrace_get+0x1e) [0x7f64c8e485fe] -> /usr/lib/dovecot/libdovecot.so.0(+0xfc49b) [0x7f64c8e5449b] -> /usr/lib/dovecot/libdovecot.so.0(+0xfc531) [0x7f64c8e54531] -> /usr/lib/dovecot/libdovecot.so.0(+0x53aee) [0x7f64c8dabaee] -> /usr/lib/dovecot/libdovecot.so.0(+0x4751c) [0x7f64c8d9f51c] -> /usr/lib/dovecot/libdovecot.so.0(+0x7b605) [0x7f64c8dd3605] -> /usr/lib/dovecot/libdovecot.so.0(+0x122171) [0x7f64c8e7a171] -> /usr/lib/dovecot/libdovecot.so.0(io_loop_call_io+0x69) [0x7f64c8e69f59] -> /usr/lib/dovecot/libdovecot.so.0(io_loop_handler_run_internal+0x132) [0x7f64c8e6b592] -> /usr/lib/dovecot/libdovecot.so.0(io_loop_handler_run+0x50) [0x7f64c8e6a000] -> /usr/lib/dovecot/libdovecot.so.0(io_loop_run+0x40) [0x7f64c8e6a1c0] -> /usr/lib/dovecot/libdovecot.so.0(master_service_run+0x13) [0x7f64c8de04e3] -> dovecot/submission(main+0x4df) [0x562f3ac7c11f] -> /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xea) [0x7f64c8ba4d0a] -> dovecot/submission(_start+0x2a) [0x562f3ac7c1aa]

Error message is configured in exim4.conf with

begin routers

mytestrouter: [...] cannot_route_message = aa bbbbbbbbbb ccccccc dd eeeeeeeeeeee ffffffffffff gggggggggg hh iiiiii  jj kk llll   mmmmmmmmmm nnn o ppppppppppppppp rrrrrr ssssss t uuuu w xxxxxxx yyyyyy zzzzzzzz aa bbbbbbbbbbb cccccccc   dd eeeeee fff gggggg hhhhhhh iiiiiiii jj kkkkkk  ll mm nnnn  ooooo  ppppppp qqqq r ssss tttttt uuuuuuuuuuuuu www xxx yyyyyyy zzzzz aaaaa bbbbbbbbb ccc ddddddd

Dovecot installed from up-to-date Debian 11 package:

# dpkg -s dovecot-core | grep Version Version: 1:2.3.13+dfsg1-2+deb11u1

-- Regards, Paweł Bogusławski

IB Development Team E: dev@ib.pl