Szerző: Mike Tubby Dátum: Címzett: Exim User List Tárgy: [exim] Devuan Chimaera + Exim + MariaDB 10.5.12 weirdness (and
potential workaround)
All,
Upgraded my public email server from Devuan 3.1 Beowulf to Devuan 4.0
Chimaera this afternoon and Exim stopped working ... fair enough, it's a
custom build for the platform so did:
cd /root/exim-4.94
make clean
make makefile
make
make install
then:
service exim restart
but my system kept returning 451 Temporary local problem - like this:
mike@public:~$ telnet localhost 25
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
451 Temporary local problem - please try later
Connection closed by foreign host.
So, ran it with some debug:
exim -bd -d+all -q15m 2>&1 | tee /tmp/a
in order to see and capture what was going on.
Now, my system has a lot of MySQL integration for whitelists/blacklists,
virtual domains, virtual users, DKIM, aliases, vacation messages and more.
I found it bailing out in the ACL for accept connection which uses a
blacklist_hosts table and the Exim MySQL query was bailing out with:
MYSQL: query failed: Unknown MySQL error
It was aparrent that the problem was related to look-ups so I added
debug to src/lookups/mysql.c to print additional info and still I
couldn't see what was wrong - I could trigger the error by telnetting to
localhost:25 from another window and got this (mysql related) stuff in
the logs:
root@public:/etc/exim# grep -i mysql /tmp/c
Lookups (built-in): lsearch wildlsearch nwildlsearch iplsearch dbm
dbmjz dbmnz dnsdb mysql passwd
Library version: MySQL: Compile: 100512 10.5.12 [mariadb-10.5]
Lookups (built-in): lsearch wildlsearch nwildlsearch iplsearch dbm
dbmjz dbmnz dnsdb mysql passwd
Library version: MySQL: Compile: 100512 10.5.12 [mariadb-10.5]
23577 search_open: mysql "NULL"
23577 type=mysql key="SELECT address FROM blacklist_hosts WHERE
active='1'" opts=NULL
23577 MySQL query: "SELECT address FROM blacklist_hosts WHERE
active='1'" opts 'NULL'
23577 MYSQL new connection: host=localhost port=3306 socket=NULL
database=mail user=mail
23577 Attempt MYSQL query: handle: 0x55cb0a75e330 query: SELECT
address FROM blacklist_hosts WHERE active='1'
23577 MYSQL query result: handle: 0x55cb0a75e330 rc: -1
23577 MYSQL: query failed: Unknown MySQL error
23577 lookup deferred: MYSQL: query failed: Unknown MySQL error
23577 failed to expand "<; ${lookup mysql{SELECT address FROM
blacklist_hosts WHERE active='1'}{${sg{$value}{\\n}{ ; }} }}" while
checking a list: lookup of "SELECT address FROM blacklist_hosts WHERE
active='1'" gave DEFER: MYSQL: query failed: Unknown MySQL error
23577 H=localhost [127.0.0.1] temporarily rejected connection in
"connect" ACL: MYSQL: query failed: Unknown MySQL error
23577 close MYSQL connection: localhost:3306/mail/mail
root@public:/etc/exim#
added even more debug and found that the query was returning -1 and
failing with "Unknown MySQL error".
Running queries from MySQL (MariaDB) CLI worked fine:
MariaDB [mail]> SELECT address FROM blacklist_hosts WHERE active='1';
+-------------------+
| address |
+-------------------+
| 119.128.0.0/12 |
| 185.24.233.166/24 |
| 77.40.0.0/16 |
| 222.184.0.0/13 |
+-------------------+
4 rows in set (0.000 sec)
So a change of direction... okay, does this new version of MariaDB
(10.5.12) work properly from the C library/API that Exim uses? Wrote a C
test program to connect to the database using the same credentials as
Exim and perform a set of queries. After a few tests I found that:
SELECT * FROM blacklist_hosts // worked
SELECT * FROM blacklist_hosts WHERE active='1' // worked
SELECT address FROM blacklist_hosts WHERE active='1' // failed with
"Unknown MySQL error"
ah, so now my C program behaved the same as Exim!
So off to the Maria-DB knowledge base in case 'address' is now a
reserved word, but alas, it is not documented as such, but as a hunch
that it might be - I tried this:
SELECT address AS a FROM blacklist_hosts WHERE active='1'
and it worked in my test harness, so updated my exim.conf:
#
# blacklist_hosts -> hosts we refuse connections from (IPv4 or IPv6
address blocks)
#
# We use this to block certain Chinese, Russian, North Korean etc.
hosts/networks from reaching us directly.
# Inbound mail should be coming via our MX chain anyway!
#
hostlist blacklist_hosts = <; ${lookup mysql{SELECT address AS a
FROM blacklist_hosts WHERE active='1'}{${sg{$value}{\\n}{ ; }} }}
Restarted Exim, now accepts connections and works as expected.
I consider this a peculiar bug/issue/problem because config and code
that used to work fine stopped working... my hunch is that "address" has
become a reserved word - if not on the CLI then on the C API and that
this broke something that used to work.
Can anyone suggest a reason for this, other than the documented use of
'address' as some sort of reserved word?