# Howdy

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Howdy is a program that imitates Windows Hello on Linux. It uses a computer's IR sensors and camera to verify a user's face.

## Installation

Install the howdyAUR package.

## Configuration

### Setup Howdy to start when needed

In order for Howdy to authenticate a user, a small change must be added to any PAM configuration file where Howdy might want to be used. The following line must be added to any configuration file:

    auth sufficient pam_python.so /lib/security/howdy/pam.py

#### Examples

This example enables howdy authentication for `sudo`:

    /etc/pam.d/sudo

    # PAM-1.0
    auth    sufficient pam_python.so /lib/security/howdy/pam.py
    auth    include    system-auth
    account include    system-auth
    session include    system-auth

Another example enabling howdy authentication for local graphical login, e.g. GDM or SDDM:

    /etc/pam.d/system-local-login

    #%PAM-1.0

    auth      sufficient   pam_python.so /lib/security/howdy/pam.py
    auth      include      system-login
    account   include      system-login
    password  include      system-login
    session   include      system-login

However, for LightDM you should edit:

    /etc/pam.d/lightdm

    #%PAM-1.0
    auth        sufficient  pam_python.so /lib/security/howdy/pam.py
    auth        include     system-login
    -auth       optional    pam_gnome_keyring.so
    account     include     system-login
    password    include     system-login
    session     include     system-login
    -session    optional    pam_gnome_keyring.so auto_start

An example with i3lock or betterlockscreen, change permissions for the howdy folder in /lib/security by running the command `chmod -R 755 /lib/security/howdy`, and edit the i3lock file:

    /etc/pam.d/i3lock

    #
    # PAM configuration file for the i3lock-color screen locker. By default, it includes
    # the 'system-auth' configuration file (see /etc/pam.d/system-auth) for Arch and Gentoo
    # and 'login' for Debian. Note that vanilla i3lock upstream uses 'login' instead.
    #

    auth sufficient pam_python.so /lib/security/howdy/pam.py
    auth include system-auth # For Arch/Gentoo
    #auth include login # For Debian

### Add correct IR sensor

Determine the correct `/dev/videoX` file connected to the IR sensor. This can be done through various programs such as cheese, fswebcamAUR or v4l-utils.

An example of doing this with a tool included in the v4l-utils package:

    $ v4l2-ctl --list-devices
    Integrated_Webcam_HD: Integrate (usb-0000:00:14.0-11):
            /dev/video0
            /dev/video1

    EyeChip: Tobii Video (usb-0000:00:14.0-3.4.3):
            /dev/video4
            /dev/video5

    HD Webcam C525 (usb-0000:00:14.0-3.4.4):
            /dev/video2
            /dev/video3

As seen in the example above, the command may show more than one webcam device, and for each device it may show multiple `/dev/videoX` paths. Generally picking the first of the two paths will work fine.

If you have more than one webcam and/or IR sensor using a `/dev/videoX` may be somewhat unstable overtime, as it may be prone to change paths if certain devices are unplugged and replugged back in. In this can consider using a more consistent path name supplied by Video 4 Linuxwikipedia:Video4Linux in the `/dev/v4l/by-id/` path.

    $ ls -l /dev/v4l/by-id
    total 0
    lrwxrwxrwx 1 root root 12 Dec  3 15:01 usb-046d_HD_Webcam_C525_BE4703F0-video-index0 -> ../../video2
    lrwxrwxrwx 1 root root 12 Dec  3 15:01 usb-046d_HD_Webcam_C525_BE4703F0-video-index1 -> ../../video3
    lrwxrwxrwx 1 root root 12 Dec  3 14:47 usb-CNFGH19N306021000582_Integrated_Webcam_HD-video-index0 -> ../../video0
    lrwxrwxrwx 1 root root 12 Dec  3 14:47 usb-CNFGH19N306021000582_Integrated_Webcam_HD-video-index1 -> ../../video1
    lrwxrwxrwx 1 root root 12 Dec  3 14:47 usb-Tobii_Technology_AB_EyeChip_IS404-100109244721-video-index0 -> ../../video4
    lrwxrwxrwx 1 root root 12 Dec  3 14:47 usb-Tobii_Technology_AB_EyeChip_IS404-100109244721-video-index1 -> ../../video5

You can validate that these `v4l` paths do not change by unplugging and replugging your devices and then re-listing the directory.

Once the correct filename is found, edit `/lib/security/howdy/config.ini` using either your preferred editor or with `howdy config` (run as the root user).

To customize which editor `howdy config` uses, set the `EDITOR` variable:

    # EDITOR=editor howdy config

### Add face to Howdy

In order to add a face model to Howdy, run `sudo howdy add`.

## Troubleshooting

### IR emitter does not work

If the IR camera is on and the IR emitter does not work, one possible situation is that you chose the wrong file. For example, `/dev/video0` and `/dev/video2` both work fine to recognize your face, but only `/dev/video2` will turn on the IR emitter. So make sure you have checked all `/dev/videoX`.

Otherwise you should follow the instructions from linux-enable-ir-emitter to enable the IR emitter.

### Testing your IR camera

It can be useful to first make verify that your IR camera functions correctly. A set of 10 jpg photos can be taken to test your device using the gstreamer package with the following command (replacing `IR camera` with the location of your IR camera):

    gst-launch-1.0 v4l2src device=IR camera num-buffers=10 ! image/jpeg ! multifilesink location="frame-%02d.jpg"

### Howdy does not seem to work

Verify that Howdy is properly working by running `howdy test` as root. If that seems to work, check any PAM configuration files and verify they are working. Some programs, such as SDDM [1], do not work properly with PAM, which may result in unexpected results.

### Errors recognizing an input device

Some IR sensors (for example of the Thinkpad T480) need to have the frame width and height defined in the configuration file:

    frame_width = 400
    frame_height = 400

The width and height of your sensor output: `v4l2-ctl --list-devices --all`.

### GStreamer warnings in shell

You might have howdy working but get warning like this in shell:

    # howdy test

    [ WARN:0] global /build/opencv/src/opencv-4.1.1/modules/videoio/src/cap_gstreamer.cpp (1756) handleMessage OpenCV | GStreamer warning: Embedded video playback halted; module source reported: Could not read from resource.
    [ WARN:0] global /build/opencv/src/opencv-4.1.1/modules/videoio/src/cap_gstreamer.cpp (886) open OpenCV | GStreamer warning: unable to start pipeline
    [ WARN:0] global /build/opencv/src/opencv-4.1.1/modules/videoio/src/cap_gstreamer.cpp (480) isPipelinePlaying OpenCV | GStreamer warning: GStreamer: pipeline have not been created
    ...

This is caused by upstream opencv package built with default warning level `LOG_LEVEL_WARNING = 3`. The cv::utils::logging API in C++ can set log level higher in order to hide lower level warning, but this API is not exposed into python-cv2 yet.

A temporary solution for this is adding an environment variable `OPENCV_LOG_LEVEL=ERROR` to your system per user or globally.

Note: This will make the warning disappear but might hide other potential problems.

This issue was fixed in this commit.

Category:

- Authentication