#### Beyond Linux® From Scratch (System V Edition) - Version 12.3

### Chapter 15. Networking Programs

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# wpa_supplicant-2.11

## Introduction to WPA Supplicant

WPA Supplicant is a Wi-Fi Protected Access (WPA) client and IEEE 802.1X supplicant. It implements WPA key negotiation with a WPA Authenticator and Extensible Authentication Protocol (EAP) authentication with an Authentication Server. In addition, it controls the roaming and IEEE 802.11 authentication/association of the wireless LAN driver. This is useful for connecting to a password protected wireless access point.

This package is known to build and work properly using an LFS 12.3 platform.

### Package Information

- Download (HTTP): https://w1.fi/releases/wpa_supplicant-2.11.tar.gz

- Download MD5 sum: 72a4a00eddb7a499a58113c3361ab094

- Download size: 3.7 MB

- Estimated disk space required: 35 MB

- Estimated build time: 0.3 SBU

### WPA Supplicant Dependencies

#### Required (Runtime)

Configuring the Linux Kernel for Wireless

#### Recommended

libnl-3.11.0

#### Optional

dbus-1.16.0 and libxml2-2.13.6

## Kernel Configuration

To use wpa_supplicant, the kernel must have the appropriate drivers and other support available. Read Configuring the Linux Kernel for Wireless for details.

## Installation of WPA Supplicant

First you will need to create an initial configuration file for the build process. You can read `wpa_supplicant/README` and `wpa_supplicant/defconfig` for the explanation of the following options as well as other options that can be used. Create a build configuration file that should work for standard WiFi setups by running the following command:

    cat > wpa_supplicant/.config << "EOF"
    CONFIG_BACKEND=file
    CONFIG_CTRL_IFACE=y
    CONFIG_DEBUG_FILE=y
    CONFIG_DEBUG_SYSLOG=y
    CONFIG_DEBUG_SYSLOG_FACILITY=LOG_DAEMON
    CONFIG_DRIVER_NL80211=y
    CONFIG_DRIVER_WEXT=y
    CONFIG_DRIVER_WIRED=y
    CONFIG_EAP_GTC=y
    CONFIG_EAP_LEAP=y
    CONFIG_EAP_MD5=y
    CONFIG_EAP_MSCHAPV2=y
    CONFIG_EAP_OTP=y
    CONFIG_EAP_PEAP=y
    CONFIG_EAP_TLS=y
    CONFIG_EAP_TTLS=y
    CONFIG_IEEE8021X_EAPOL=y
    CONFIG_IPV6=y
    CONFIG_LIBNL32=y
    CONFIG_PEERKEY=y
    CONFIG_PKCS12=y
    CONFIG_READLINE=y
    CONFIG_SMARTCARD=y
    CONFIG_WPS=y
    CFLAGS += -I/usr/include/libnl3
    EOF

If you wish to use WPA Supplicant with NetworkManager-1.50.0, make sure that you have installed dbus-1.16.0, then add the following options to the WPA Supplicant build configuration file by running the following command:

    cat >> wpa_supplicant/.config << "EOF"
    CONFIG_CTRL_IFACE_DBUS=y
    CONFIG_CTRL_IFACE_DBUS_NEW=y
    CONFIG_CTRL_IFACE_DBUS_INTRO=y
    EOF

Install WPA Supplicant by running the following commands:

    cd wpa_supplicant &&
    make BINDIR=/usr/sbin LIBDIR=/usr/lib

This package does not come with a test suite.

Now, as the `root` user:

    install -v -m755 wpa_{cli,passphrase,supplicant} /usr/sbin/ &&
    install -v -m644 doc/docbook/wpa_supplicant.conf.5 /usr/share/man/man5/ &&
    install -v -m644 doc/docbook/wpa_{cli,passphrase,supplicant}.8 /usr/share/man/man8/

If you have built WPA Supplicant with D-Bus support, you will need to install D-Bus configuration files. Install them by running the following commands as the `root` user:

    install -v -m644 dbus/fi.w1.wpa_supplicant1.service \
                     /usr/share/dbus-1/system-services/ &&
    install -v -d -m755 /etc/dbus-1/system.d &&
    install -v -m644 dbus/dbus-wpa_supplicant.conf \
                     /etc/dbus-1/system.d/wpa_supplicant.conf

### Note

You will need to restart the system D-Bus daemon before you can use the WPA Supplicant D-Bus interface.

## Configuring wpa_supplicant

### Important

If you are using WPA Supplicant with NetworkManager-1.50.0 (or anything communicating with WPA Supplicant via D-Bus), this section should be skipped. Running a D-Bus connected WPA Supplicant instance and another WPA supplicant instance configured following this section simultaneously can cause subtle issues.

### Config File

`/etc/sysconfig/wpa_supplicant-*.conf`

### Configuration Information

To connect to an access point that uses a password, you need to put the pre-shared key in `/etc/sysconfig/wpa_supplicant-`wifi0`.conf`. SSID is the string that the access point/router transmits to identify itself. Run the following command as the `root` user:

    wpa_passphrase SSID SECRET_PASSWORD > /etc/sysconfig/wpa_supplicant-wifi0.conf

`/etc/sysconfig/wpa_supplicant-`wifi0`.conf` can hold the details of several access points. When wpa_supplicant is started, it will scan for the SSIDs it can see and choose the appropriate password to connect.

If you want to connect to an access point that isn't password protected, put an entry like this in `/etc/sysconfig/wpa_supplicant-`wifi0`.conf`. Replace "Some-SSID" with the SSID of the access point/router.

    network={
      ssid="Some-SSID"
      key_mgmt=NONE
    }

Connecting to a new access point that is not in the configuration file can be accomplished manually via the command line, but it must be done via a privileged user. To do that, add the following to the configuration file:

    ctrl_interface=DIR=/run/wpa_supplicant GROUP=<privileged group>
    update_config=1

Replace the <privileged group> above with a system group where members have the ability to connect to a wireless access point.

There are many options that you could use to tweak how you connect to each access point. They are described in some detail in the `wpa_supplicant/wpa_supplicant.conf` file in the source tree.

### Connecting to an Access Point

If you want to configure network interfaces at boot using wpa_supplicant, you need to install the `/lib/services/wpa` script included in blfs-bootscripts-20250225 package:

    make install-service-wpa

If your router/access point uses DHCP to allocate IP addresses, you can install dhcpcd-10.2.2 and use it to automatically obtain network addresses. Create the `/etc/sysconfig/ifconfig-`wifi0`` by running the following command as the `root` user:

    cat > /etc/sysconfig/ifconfig.wifi0 << "EOF"
    ONBOOT="yes"
    IFACE="wlan0"
    SERVICE="wpa"

    # Additional arguments to wpa_supplicant
    WPA_ARGS=""

    WPA_SERVICE="dhcpcd"
    DHCP_START="-b -q <insert appropriate start options here>"
    DHCP_STOP="-k <insert additional stop options here>"
    EOF

Alternatively, if you use static addresses on your local network, then create the `/etc/sysconfig/ifconfig-`wifi0`` by running the following command as the `root` user:

    cat > /etc/sysconfig/ifconfig.wifi0 << "EOF"
    ONBOOT="yes"
    IFACE="wlan0"
    SERVICE="wpa"

    # Additional arguments to wpa_supplicant
    WPA_ARGS=""

    WPA_SERVICE="ipv4-static"
    IP="192.168.1.1"
    GATEWAY="192.168.1.2"
    PREFIX="24"
    BROADCAST="192.168.1.255"
    EOF

You can connect to the wireless access point by running the following command as the `root` user:

    ifup wifi0

Replace `wlan0` with the correct wireless interface and `wifi0` with desired name for the configuration file. Please note that `wpa_supplicant-*.conf` and `ifconfig.*` configuration files need to have identical names, ie both contain `wifi0` in their name.

## Contents

Installed Programs: wpa_supplicant, wpa_passphrase and wpa_cli
Installed Libraries: None
Installed Directories: None

### Short Descriptions

wpa_supplicant | is a daemon that can connect to a password protected wireless access point
wpa_passphrase | takes an SSID and a password and generates a simple configuration that wpa_supplicant can understand
wpa_cli | is a command line interface used to control a running wpa_supplicant daemon

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