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.
![[Note]](../images/note.png)
Note
Development versions of BLFS may not build or run
some packages properly if LFS or dependencies have been updated
since the most recent stable versions of the books.
Package Information
WPA Supplicant Dependencies
Required (Runtime)
Configuring the Linux Kernel for Wireless
Recommended
desktop-file-utils-0.27 (for running
update-desktop-database) and
libnl-3.8.0
Optional
libxml2-2.12.1, and
(Qt-5.15.11 or qt-alternate-5.15.11)
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-1.44.2, make sure that you have installed
dbus-1.14.10 and libxml2-2.12.1, 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
If you have installed (Qt-5.15.11 or qt-alternate-5.15.11) and wish to build
the WPA Supplicant GUI program, run
the following commands:
pushd wpa_gui-qt4 &&
qmake wpa_gui.pro &&
make &&
popd
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/
Install the systemd support files by
running the following command as the root user:
install -v -m644 systemd/*.service /usr/lib/systemd/system/
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
Additionally, enable the wpa_supplicant.service
so that systemd can properly activate the
D-Bus service. Note that the
per-connection service and the D-Bus service cannot be enabled
at the same time. Run the following command as the
root user:
systemctl enable wpa_supplicant
If you have built the WPA Supplicant GUI
program, install it by running the following commands as the
root user:
install -v -m755 wpa_gui-qt4/wpa_gui /usr/bin/ &&
install -v -m644 doc/docbook/wpa_gui.8 /usr/share/man/man8/ &&
install -v -m644 wpa_gui-qt4/wpa_gui.desktop /usr/share/applications/ &&
install -v -m644 wpa_gui-qt4/icons/wpa_gui.svg /usr/share/pixmaps/
Note
You will need to restart the system D-Bus daemon
before you can use the WPA Supplicant
D-Bus interface.
Note
This package installs desktop files into the
/usr/share/applications
hierarchy and you can improve system performance and memory usage by
updating /usr/share/applications/mimeinfo.cache.
To perform the update you must have
desktop-file-utils-0.27 installed and issue the following
command as the root user:
update-desktop-database -q
Configuring wpa_supplicant
Config File
/etc/wpa_supplicant/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/wpa_supplicant/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:
install -v -dm755 /etc/wpa_supplicant &&
wpa_passphrase SSID SECRET_PASSWORD > /etc/wpa_supplicant/wpa_supplicant-wifi0.conf
/etc/wpa_supplicant/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/wpa_supplicant/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 or GUI, 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
There are 3 types of systemd units
that were installed:
The only difference between 3 of them is what driver
is used for connecting (-D option). The first one uses
the default driver, the second one uses the nl80211
driver and the third one uses the wired driver.
You can connect to the wireless access point by
running the following command as the
root user:
systemctl start wpa_supplicant@wlan0
To connect to the wireless access point at
boot, simply enable the appropriate
wpa_supplicant service
by running the following command as the
root user:
systemctl enable wpa_supplicant@wlan0
Depending on your setup, you can replace the
wpa_supplicant@.service
with any other listed above.
To assign a network address to your wireless interface, consult the
General Network Configuration
page in LFS.