BenV's notes

Archive for 2014

Check_MK plugin: fail2ban

by on Nov.03, 2014, under Check MK

This one has been on my todo list for a while, so today I took a stab at it: a fail2ban plugin for Check_MK.
My previous plugin (LMSensors plugin for Check_MK) still gets quite a few hits, so I figured you guys might like this one as well.

Why? Pretty graphs of course 😉
Another reason might be that you want to keep an eye on how many ssh bots etc fail2ban keeps out. (continue reading…)

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Lua 5.2.3 on Slackware64 14.1

by on Jul.04, 2014, under Software

Just ran into this one, noting it down for anyone else with this error:

Trying to compile Lua 5.2.3 (which should try to invest some in autoconf / cmake or something) gave me this lovely error:

make[2]: Entering directory `/usr/src/lua-5.2.3/src'
gcc -o lua lua.o liblua.a -lm -Wl,-E -ldl -lreadline
/usr/lib64/gcc/x86_64-slackware-linux/4.8.2/../../../../lib64/libreadline.so: undefined reference to `tputs'
echo Stom product, Makefile editen, dan make MYLIBS="-lncurses" anders breekt ie op readline.
/usr/lib64/gcc/x86_64-slackware-linux/4.8.2/../../../../lib64/libreadline.so: undefined reference to `tgoto'
/usr/lib64/gcc/x86_64-slackware-linux/4.8.2/../../../../lib64/libreadline.so: undefined reference to `tgetflag'
/usr/lib64/gcc/x86_64-slackware-linux/4.8.2/../../../../lib64/libreadline.so: undefined reference to `UP'
/usr/lib64/gcc/x86_64-slackware-linux/4.8.2/../../../../lib64/libreadline.so: undefined reference to `tgetent'
/usr/lib64/gcc/x86_64-slackware-linux/4.8.2/../../../../lib64/libreadline.so: undefined reference to `tgetnum'
/usr/lib64/gcc/x86_64-slackware-linux/4.8.2/../../../../lib64/libreadline.so: undefined reference to `PC'
/usr/lib64/gcc/x86_64-slackware-linux/4.8.2/../../../../lib64/libreadline.so: undefined reference to `tgetstr'
/usr/lib64/gcc/x86_64-slackware-linux/4.8.2/../../../../lib64/libreadline.so: undefined reference to `BC'
collect2: error: ld returned 1 exit status
make[2]: *** [lua] Error 1
make[2]: Leaving directory `/usr/src/lua-5.2.3/src'
make[1]: *** [linux] Error 2
make[1]: Leaving directory `/usr/src/lua-5.2.3/src'
make: *** [linux] Error 2

Reason: it needs to link against ncursus in Slackware (or alternatively libtermcap, but ncursus worked for me).
Solution – use make MYLIBS=”-lncursus”:

make MYLIBS="-lncurses"
cd src && make linux
make[1]: Entering directory `/usr/src/lua-5.2.3/src'
make all SYSCFLAGS="-DLUA_USE_LINUX" SYSLIBS="-Wl,-E -ldl -lreadline"
make[2]: Entering directory `/usr/src/lua-5.2.3/src'
gcc -o lua lua.o liblua.a -lm -Wl,-E -ldl -lreadline -lncurses
gcc -o luac luac.o liblua.a -lm -Wl,-E -ldl -lreadline -lncurses
make[2]: Leaving directory `/usr/src/lua-5.2.3/src'
make[1]: Leaving directory `/usr/src/lua-5.2.3/src'

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Breaking slackpkg in unexpected ways

by on Jul.04, 2014, under Software

I just ran into something funny:

root@machine:~$ slackpkg update

Your slackpkg.conf is outdated. Please, edit it using slackpkg.conf.new
as example or overwrite it with slackpkg.conf.new.

You can use 'slackpkg new-config' to do that.

root@machine:~$

Huh. I didn’t do anything weird with slackpkg….
Waaait a minute…

root@machine:~$ unset GREP_OPTIONS
root@machine:~$ slackpkg update
# Cut out the fetching of Changelog.txt
No changes in ChangeLog.txt between your last update and now.
Do you really want to download all other files (y/N)?

Apparently slackpkg breaks if you set GREP_OPTIONS to “–color=always”. Good to know for when I break it this way next time 😉

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Linux 3.13 released!

by on Jan.20, 2014, under Software

Yay, another new linux kernel. Of course this broke the closed NVidia driver, I tried 331.38:

[ 110.917769] nvidia: Unknown symbol acpi_os_wait_events_complete (err 0)

The fix for this is easy, unpack the installer and then patch file kernel/nv-acpi.c hack out line 306:

// NV_ACPI_OS_WAIT_EVENTS_COMPLETE();

Run nvidia-installer and you should be good to go. Incredible that it always takes NVidia forever to fix these things, this bug has been known since at least 3.13-rc1. Oh well.

Next up, testing nftables. Looks like iptables will soon be obsolete 🙂
Here’s a nice howto to get you started – https://home.regit.org/netfilter-en/nftables-quick-howto/.
Update:
Might you be wondering (like me) where the heck the libnftables git repository went: they decided to rename the thing to libnftnl. You can find the repository here – https://git.netfilter.org/libnftnl/

Another thing: compiling nftables from git breaks on my Slackware64-current machine atm because 1. configure.ac still points to libnftables (instead of libnftl), I assume this will be fixed within the hour. 2: it tries to compile against libreadline without linking libncurses.
Fix for that is running configure like: LDFLAGS=-lncurses ./configure

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