[Dovecot] Panic: file mempool-system.c: line 104

[Martins Lazdans]

Hello!

I have used Dovecot for more than a year without problems, but today it
just crashed with this message:

dovecot: Apr 09 21:23:38 Panic: file mempool-system.c: line 104
(pool_system_realloc): assertion failed: (old_size == (size_t)-1 || mem
== NULL || old_size <= malloc_usable_size(mem))
dovecot: Apr 09 21:23:38 Error: Raw backtrace: /usr/local/sbin/dovecot
[0x805757c] -> /usr/local/sbin/dovecot [0x8057664] ->
/usr/local/sbin/dovecot [0x80514e9] -> /usr/local/sbin/dovecot
[0x8056edb] -> /usr/local/sbin/dovecot [0x805bcc1] ->
/usr/local/sbin/dovecot [0x8055bbf] -> /usr/local/sbin/dovecot
[0x8055d3b] -> /usr/local/sbin/dovecot [0x8055d87] ->
/usr/local/sbin/dovecot [0x8062448] -> /usr/local/sbin/dovecot
[0x805aadf] -> /usr/local/sbin/dovecot [0x805a5a7] ->
/usr/local/sbin/dovecot [0x804d63a] -> /usr/local/sbin/dovecot
[0x804da67] -> /usr/local/sbin/dovecot [0x804e4ce] ->
/usr/local/sbin/dovecot [0x805a17a] -> /usr/local/sbin/dovecot
[0x805adac] -> /usr/local/sbin/dovecot [0x8059f89] ->
/usr/local/sbin/dovecot [0x8051b43] ->
/lib/libc.so.6(__libc_start_main+0xd8) [0xb7e49df8] ->
/usr/local/sbin/dovecot [0x804a451]

dovecot --version
1.1.7

It seems, than some brute force attack caused this, here some more log:
> dovecot: Apr 09 21:23:36 Info: auth(default): client out: FAIL  1       user=jennie
> dovecot: Apr 09 21:23:36 Info: auth(default): client out: FAIL  1       user=jeffrey
> dovecot: Apr 09 21:23:36 Info: auth(default): client out: FAIL  1       user=job
> dovecot: Apr 09 21:23:36 Info: auth-worker(default): sql(jimmy,81.149.214.201): query: SELECT password FROM mailbox WHERE username = 'jimmy' AND active = '1'
> dovecot: Apr 09 21:23:36 Info: auth(default): client in: AUTH   1       PLAIN   service=pop3    lip=195.3.144.29        rip=81.149.214.201      lport=110       rport=34646     resp=<hidden>
> dovecot: Apr 09 21:23:36 Info: auth-worker(default): sql(jimmy,81.149.214.201): unknown user

For now I blocked this one IP (81.149.214.201), but wondering if this
could happen again in the future?

Don`t really understand what`s the problem. I have ~2Gb of memory free,
so it can not be a out of memory issue.

Any ideas?

Thank you!

-- 
Martins Lazdans