transport-haproxy.c - Bail out Error. Code should not be reached #5516
Description
Hi Everyone,
It looks like since lib/transport/transport-haproxy.c was implemented, you have the possibility to run into the scenario described below.
commit hash: 4e9dae7
syslog-ng
Version of syslog-ng
syslog-ng 4 (4.10.1)
Platform
Ubuntu 22.04 jammy
Debug bundle
Syslog-NG DEBUg buNdle generator
Start environment detection
Linux-type FHS detected
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 22.04.5 LTS
Release: 22.04
Codename: jammy
Operating System Name: Linux
Debian specific checks
Check package files integrity
??5?????? c /etc/syslog-ng/syslog-ng.conf
Package syslog-ng-core files are intact
Package syslog-ng-mod-xml-parser files are intact
list syslog-related packages
Start general info collection
System's full uname: Linux syslog-server 5.15.0-157-generic #167-Ubuntu SMP Wed Sep 17 21:35:53 UTC 2025 x86_64 x86_64 x86_64 GNU/Linux
Getting network-interface information: Success
Getting network routes: Success
Getting DNS resolution-related information: Done
List all processes
Mount and disk free info collection
Start Syslog-specific info collection
Copy configuration files from /etc/syslog-ng
134 blocks
Copy SCL configuration files
1 block
Gathering PKI information... done.
SVpid: 1 SNGpid: 193531 Chpids:
Syslog-ng's exact version: syslog-ng 4 (4.10.1)
/usr/sbin/syslog-ng-ctl stats
/usr/sbin/syslog-ng-ctl query get *
/usr/sbin/syslog-ng-ctl show-license-info
/usr/sbin/syslog-ng-ctl credentials status
33 blocks
dpkg-query: no path found matching pattern /lib/x86_64-linux-gnu/libglib-2.0.so.0
dpkg-query: no path found matching pattern /lib/x86_64-linux-gnu/libgmodule-2.0.so.0
dpkg-query: no path found matching pattern /lib/x86_64-linux-gnu/libpcre2-8.so.0
dpkg-query: no path found matching pattern /lib/x86_64-linux-gnu/libsystemd.so.0
dpkg-query: no path found matching pattern /lib/x86_64-linux-gnu/libssl.so.3
dpkg-query: no path found matching pattern /lib/x86_64-linux-gnu/libcrypto.so.3
dpkg-query: no path found matching pattern /lib/x86_64-linux-gnu/liburing.so.2
dpkg-query: no path found matching pattern /lib/x86_64-linux-gnu/libzstd.so.1
dpkg-query: no path found matching pattern /lib/x86_64-linux-gnu/liblz4.so.1
dpkg-query: no path found matching pattern /lib/x86_64-linux-gnu/libgcrypt.so.20
Detecting init system: systemd detected...
Generating second batch of statistics
/usr/sbin/syslog-ng-ctl stats
/usr/sbin/syslog-ng-ctl query get *
Generating hashes... done.
Debug Bundle generation: Done.
tar: ./var/syslog-ng.ctl: socket ignored
Issue
Failure
ERROR:../../lib/transport/transport-haproxy.c:535:_save_addresses: code should not be reached
Bail out! ERROR:../../lib/transport/transport-haproxy.c:535:_save_addresses: code should not be reached
syslog-ng.service: Main process exited, code=killed, status=6/ABRT
syslog-ng.service: Failed with result 'signal'.
Steps to reproduce
Configure HAProxy to forward Syslog events to your Syslog-ng server using send-proxy-v2 specifically.
E.G.
server syslog2 1923.168.1.2:514 send-proxy-v2
No health check configuration required for this to reproduce the issue.
I am using HAProxy version 3.0 here.
Enable Proxy Protocol for your network() source:
source s_tcp_pp {
channel {
source {
network(
port(514)
ip(0.0.0.0)
transport("proxied-tcp")
max-connections(100)
flags(syslog-protocol)
);
};
};
};
HAProxy will send a packet/s to your Syslog-ng server that contains the following payload, which causes the bail out error.
0d0a 0d0a 000d 0a51 5549 540a 2000 0000
In HAProxy's proxy protocol document under the section titled: '2.2. Binary header format (version 2)', it describes the header in question.
https://www.haproxy.org/download/3.0/doc/proxy-protocol.txt
'The lowest four bits represents the command' seems to indicate a 'LOCAL' command was sent and no address family included either, which I believe might be causing g_assert_not_reached() to trigger in transport-haproxy.c :535
In my testing, I seem to be able to trigger payload being sent by either restarting the HAProxy or Syslog-ng service.
Some more testing I did to make 100% sure it is actually this payload causing the problem:
I just configured my iptables on my Syslog-ng server to filter out and drop packets that contain it.
E.G.
-A INPUT -p tcp -m tcp --dport 514 -m string --hex-string "|515549540a20000000|" --algo bm --to 65535 -j DROP
It then drops the packet and Syslog-ng does not run into the error.
I will be doing some more testing by spinning up another instance of HAProxy that I can install the latest version on (3.2 stable) and running through a couple more scenarios.
Configuration
@version: 4.10
@include "scl.conf"
# Syslog-ng configuration file, compatible with default Debian syslogd
# installation.
# First, set some global options.
options { chain_hostnames(off); flush_lines(0); use_dns(no); use_fqdn(no);
dns_cache(no); owner("root"); group("adm"); perm(0640);
stats(freq(0)); bad_hostname("^gconfd$");
};
########################
# Sources
########################
# This is the default behavior of sysklogd package
# Logs may come from unix stream, but not from another machine.
#
source s_src {
system();
internal();
};
# If you wish to get logs from remote machine you should uncomment
# this and comment the above source line.
#
#source s_net { tcp(ip(127.0.0.1) port(1000)); };
########################
# Destinations
########################
# First some standard logfile
#
destination d_auth { file("/var/log/auth.log"); };
destination d_cron { file("/var/log/cron.log"); };
destination d_daemon { file("/var/log/daemon.log"); };
destination d_kern { file("/var/log/kern.log"); };
destination d_lpr { file("/var/log/lpr.log"); };
destination d_mail { file("/var/log/mail.log"); };
destination d_syslog { file("/var/log/syslog"); };
destination d_user { file("/var/log/user.log"); };
destination d_uucp { file("/var/log/uucp.log"); };
# This files are the log come from the mail subsystem.
#
destination d_mailinfo { file("/var/log/mail.info"); };
destination d_mailwarn { file("/var/log/mail.warn"); };
destination d_mailerr { file("/var/log/mail.err"); };
# Logging for INN news system
#
destination d_newscrit { file("/var/log/news/news.crit"); };
destination d_newserr { file("/var/log/news/news.err"); };
destination d_newsnotice { file("/var/log/news/news.notice"); };
# Some 'catch-all' logfiles.
#
destination d_debug { file("/var/log/debug"); };
destination d_error { file("/var/log/error"); };
destination d_messages { file("/var/log/messages"); };
# The root's console.
#
destination d_console { usertty("root"); };
# Virtual console.
#
destination d_console_all { file(`tty10`); };
# The named pipe /dev/xconsole is for the nsole' utility. To use it,
# you must invoke nsole' with the -file' option:
#
# $ xconsole -file /dev/xconsole [...]
#
destination d_xconsole { pipe("/dev/xconsole"); };
# Send the messages to an other host
#
#destination d_net { tcp("127.0.0.1" port(1000) log_fifo_size(1000)); };
# Debian only
destination d_ppp { file("/var/log/ppp.log"); };
########################
# Filters
########################
# Here's come the filter options. With this rules, we can set which
# message go where.
filter f_dbg { level(debug); };
filter f_info { level(info); };
filter f_notice { level(notice); };
filter f_warn { level(warn); };
filter f_err { level(err); };
filter f_crit { level(crit .. emerg); };
filter f_debug { level(debug) and not facility(auth, authpriv, news, mail); };
filter f_error { level(err .. emerg) ; };
filter f_messages { level(info,notice,warn) and
not facility(auth,authpriv,cron,daemon,mail,news); };
filter f_auth { facility(auth, authpriv) and not filter(f_debug); };
filter f_cron { facility(cron) and not filter(f_debug); };
filter f_daemon { facility(daemon) and not filter(f_debug); };
filter f_kern { facility(kern) and not filter(f_debug); };
filter f_lpr { facility(lpr) and not filter(f_debug); };
filter f_local { facility(local0, local1, local3, local4, local5,
local6, local7) and not filter(f_debug); };
filter f_mail { facility(mail) and not filter(f_debug); };
filter f_news { facility(news) and not filter(f_debug); };
filter f_syslog3 { not facility(auth, authpriv, mail) and not filter(f_debug); };
filter f_user { facility(user) and not filter(f_debug); };
filter f_uucp { facility(uucp) and not filter(f_debug); };
filter f_cnews { level(notice, err, crit) and facility(news); };
filter f_cother { level(debug, info, notice, warn) or facility(daemon, mail); };
filter f_ppp { facility(local2) and not filter(f_debug); };
filter f_console { level(warn .. emerg); };
########################
# Log paths
########################
log { source(s_src); filter(f_auth); destination(d_auth); };
log { source(s_src); filter(f_cron); destination(d_cron); };
log { source(s_src); filter(f_daemon); destination(d_daemon); };
log { source(s_src); filter(f_kern); destination(d_kern); };
log { source(s_src); filter(f_lpr); destination(d_lpr); };
log { source(s_src); filter(f_syslog3); destination(d_syslog); };
log { source(s_src); filter(f_user); destination(d_user); };
log { source(s_src); filter(f_uucp); destination(d_uucp); };
log { source(s_src); filter(f_mail); destination(d_mail); };
#log { source(s_src); filter(f_mail); filter(f_info); destination(d_mailinfo); };
#log { source(s_src); filter(f_mail); filter(f_warn); destination(d_mailwarn); };
#log { source(s_src); filter(f_mail); filter(f_err); destination(d_mailerr); };
log { source(s_src); filter(f_news); filter(f_crit); destination(d_newscrit); };
log { source(s_src); filter(f_news); filter(f_err); destination(d_newserr); };
log { source(s_src); filter(f_news); filter(f_notice); destination(d_newsnotice); };
#log { source(s_src); filter(f_cnews); destination(d_console_all); };
#log { source(s_src); filter(f_cother); destination(d_console_all); };
#log { source(s_src); filter(f_ppp); destination(d_ppp); };
log { source(s_src); filter(f_debug); destination(d_debug); };
log { source(s_src); filter(f_error); destination(d_error); };
log { source(s_src); filter(f_messages); destination(d_messages); };
log { source(s_src); filter(f_console); destination(d_console_all);
destination(d_xconsole); };
log { source(s_src); filter(f_crit); destination(d_console); };
# All messages send to a remote site
#
#log { source(s_src); destination(d_net); };
###
# Include all config files in /etc/syslog-ng/conf.d/
###
@include "/etc/syslog-ng/conf.d/*.conf"