An OpenBSD Workstation

The most important feature of any workstation is getting a terminal that is pleasant to use. By default most terminals render text with a heavier weight than I would like. To solve this select a font with a light or book variation. Here is my invocation for the simple terminal

st -f 'Hermit:light:pixelsize=14:antialias=true:autohint=true'

My st port includes

The solarized color scheme

A modification to render bold fonts with the weight normal

The really compelling feature of st is that it automatically substitutes glyphs from the default font if the one you've selected does not contain them. This enables me to use the really excellent Hermit font while retaining the extended character set of DejaVu Sans.

To ensure you get full Unicode support from applications such as mutt or tmux set your language type using

LC_CTYPE =en_US.UTF-8 export LC_CTYPE

Resource Limits

The default process limits on OpenBSD are not nearly generous enough to run applications such as Gimp or Chromium Be sure to raise the limits for memory and open files by modifying /etc/login.conf

staff : \ : datasize-cur = 16384M : \ : openfiles = 16384 : \ : maxproc = 1024 : \

Terminate your X session with Ctrl+Alt+Backspace to ensure settings have taken effect.

Suspend & Resume

zzz and ZZZ are shortcuts for suspend and hibernate if apmd is run at startup. The -A flag will automatically scale the CPU frequency to save power.

Another feature of apmd(8) is to react to a low battery by hibernating or sleeping. This change to rc.conf.local reacts to a battery level of 8% or less

apmd_flags = " -A -Z 8 "

X Configuration: .xsession

xset -b while true ; do batt = " $( sysctl -n hw.sensors.acpibat0.watthour3 | cut -f 1, 2 -d " " ) " xsetroot -name " $batt " sleep 60 done & xsetroot -solid gray40 exec dwm

xset -b disables the annoying beep that terminals sometimes make.

I run a loop in the background that read the available battery life (Wh) and updates the window manager's display area. Any sensor data can be included in such output.

Finally set the background color and start your favorite window manager.

Switch to an External Monitor

As far as I know, OpenBSD does not have a native way of reacting to display plug events. When connecting an external monitor I run a little script to adjust the display

xrandr --output DP-1 --auto --primary xrandr --output eDP-1 --off xrandr --output HDMI-1 --off

Where eDP-1 is the LCD pannel on my laptop.

tmux

There's only a few tweaks I make to my terminal multiplexor's configuration. I frequently run entr in a smaller pane on the bottom

bind-key C-t split-window -p 25

I don't know of a terminal color picker, but they can be printed with a shell loop.

for i in `jot 255 ` ; do printf " \033 [38;5; ${ i } mcolour ${ i }

" done

Then I set status background and active border to bright green

set -g status-bg colour118 set -g pane-active-border-fg colour118 set -g pane-border-fg colour30

Most importantly, clean up the status bar so that only the window names are displayed:

set -g status-left '' set -g status-right ''

Using Disk Encryption

OpenBSD provides software RAID by way of a virtual host bus adapter called softraid0 . This HBA is also used for setting up disk encryption. To set use a disklabel (in my case for sd0g /home set the partition type to RAID

# disklabel -E /dev/sd0c Label editor (enter '?' for help at any prompt) /dev/sd0c> m partition to modify: [] l offset: [141362304] size: [358755776] FS type: [4.2BSD] RAID /dev/sd0c*> q Write new label?: [y]

Now configure it for crypto using -c C

# bioctl -c C -l /dev/sd0j softraid0 New passphrase: Re-type passphrase: softraid0: CRYPTO volume attached as sd1

Mount it using the same command. The kernel log will show a new virtual device appear

sd1 at scsibus3 targ 1 lun 0: <OPENBSD, SR CRYPTO, 006> sd1: 175173MB, 512 bytes/sector, 358755248 sectors

Now add a disklabel and format the encrypted volume

$ doas disklabel -E /dev/sd1c $ doas newfs /dev/rsd1a

Devices in OpenBSD may be mounted by device name or by disklabel UID which is a random id generated when the label is created.

$ disklabel /dev/sd1c | grep uid duid: 5005bf4c398ff7b9

It's this ID that we'll to mount the volume, in this way plugging in other drives won't confuse mount after we prompt the user for a password on boot. Adding the following to rc.local will ask for a password four times before giving up

for attept in 1 2 3 4 ; do bioctl -c C -l 6bce88736e499a49.j softraid0 && break sleep 1 done fsck -y 5005bf4c398ff7b9.a mount -o nodev,nosuid,softdep,wxallowed 5005bf4c398ff7b9.a /home

That last mount parameter wxallowed is important because it will allow you to run certain interpreters such as Python from a virtualenv in your home directory.

If you would like to enable crypto on the entire boot volume see this post by Ted Unangst.

Screen Lock

Add the following to your .xsession to automatically lock the screen after 5 minutes of activity

xidle -ne -delay 1 -timeout 7200 -program /usr/local/bin/slock &

To trigger this action when the system is suspended, create /etc/apm/suspend with an instruction to signal xidle to run the lock program

pkill -USR 1 xidle

Kerberos

If your workplace uses Kerberos there is a good chance that they provide the list of KDC servers via DNS SRV records

$ host -t srv _kerberos._udp.eradman.com

Heimdal Kerberos will do this lookup automatically. A basic configuration for /etc/heimdal/krb5.conf appears as such

[libdefaults] ignore_acceptor_hostname = true rdns = false default_realm = ERADMAN.COM [realms] ERADMAN.COM = { default_domain = ERADMAN.COM } [domain_realm] .ERADMAN.COM = ERADMAN.COM ERADMAN.COM = ERADMAN.COM

Now get a ticket

$ kinit radman@ERADMAN.COM's Password: ********* $ klist Credentials cache: FILE:/tmp/krb5cc_1000 Principal: eradman@ERADMAN.COM Issued Expires Principal Oct 31 10:02:30 2017 Oct 31 20:02:30 2017 krbtgt/ERADMAN.COM@ERADMAN.COM

Firefox

To enable Firefox to pick use Kerberos we need to point it to the GSSAPI library from the heimdal package. For automated configuration this means installing /usr/local/lib/firefox/browser/defaults/preferences/openbsd.js

pref( "network.negotiate-auth.allow-non-fqdn" , true ); pref( "network.negotiate-auth.gsslib" , "/usr/local/heimdal/lib/libgssapi.so.9.0" ); pref( "network.negotiate-auth.trusted-uris" , "eradman.com" ); pref( "network.negotiate-auth.using-native-gsslib" , false );

Since the OpenBSD build of Firefox is patched to use unveil(2), add an entry to /etc/firefox/unveil.main for allowing read of the Heimdal shared libraries

/usr/lib r /usr/local/heimdal/lib r ~/ rwc

Chromium

Chromium is not built with Kerberos support on OpenBSD, but it can be added by modifying /usr/ports/www/chromium/Makefile

120c120 < use_kerberos=false \ - > use_kerberos=true \ 131 < extra_cppflags=\"-idirafter ... \" - > extra_cppflags=\"-idirafter /usr/local/heimdal/include ... \"

Run make install and a mere 24 hours later the build should be complete. A policy file can be applied for installing the file /etc/chromium/policies/managed/openbsd.json

{ " AuthServerWhitelist ": " *.eradman.com ", " GSSAPILibraryName ": " /usr/local/heimdal/lib/libgssapi.so.9.0 " }

The OpenBSD build of Chromium is patched to use unveil(2), add an entry to /etc/chromium/unveil.main

/usr/local/heimdal/lib r /usr/lib r ~/ rwc

As well as /etc/chromium/unveil.utility_network

/usr/local/heimdal/lib r /usr/local/lib r /usr/lib r

After installing this file, navigate to chrome://policy to see if all settings applied.

Printers

The magic behind printing is not widely understood or documented. I always opt for a network printer that supports PostScript. The following example is from /etc/printcap

lp | mfc-9340cdw : \ : lp = : rm = 192.168.0.4 : rp = lp : sd = /var/spool/output/lpd : lf = /var/log/lpd-errs : office-printer : \ : lp = : rm = 10.240.212.52 : rp = office-printer : sd = /var/spool/output/office-printer : lf = /var/log/lpd-errs :

Be sure also to create spool directories

install -o root:daemon -m 775 /var/spool/output/office-printer

Now I can print from Firefox and other applications using lpr -Poffice-printer or just lpr at home.

Reducing Password Fatique with YubiKey

Yubico makes a nice little hardware key that, among other things, can be used to generate one time passwords for user authentication. The yubikey-personalization-gui is a Qt-based program that can be used to write private keys to one of two "slots". Copy the 12-digit private identity and the 32-digit secret key without spaces to like so

echo " 5c e1 e0 3e 63 a4 " | tr -d ' ' > /var/db/yubikey/ $USER .uid echo " 57 e3 af 3e 9b 51 2b 10 58 7d 33 fb d9 08 ef 7b " | tr -d ' ' > /var/db/yubikey/ $USER .key

It is also important to have the right permissions. If you are running X be sure to change the owner of each key to match it's owner so that screen lock programs can authenticate

chmod 600 /var/db/yubikey/ $USER . { key,uid } chown $USER /var/db/yubikey/ $USER . { key,uid }

Now set YubiKey as the authentication method for the group staff by editing /etc/login.conf

:auth=yubikey,passwd:

Note that auth= should come before entries that merge other configuration, such as tc= .