wpa_priv is a privilege separation helper that minimizes the size of wpa_supplicant code that needs to be run with root privileges.

If enabled, privileged operations are done in the wpa_priv process while leaving rest of the code (e.g., EAP authentication and WPA handshakes) to operate in an unprivileged process (wpa_supplicant) that can be run as non-root user. Privilege separation restricts the effects of potential software errors by containing the majority of the code in an unprivileged process to avoid the possibility of a full system compromise.

wpa_priv needs to be run with network admin privileges (usually, root user). It opens a UNIX domain socket for each interface that is included on the command line; any other interface will be off limits for wpa_supplicant in this kind of configuration. After this, wpa_supplicant can be run as a non-root user (e.g., all standard users on a laptop or as a special non-privileged user account created just for this purpose to limit access to user files even further).

The following steps are an example of how to configure wpa_priv to allow users in the wpapriv group to communicate with wpa_supplicant with privilege separation:

Create user group (e.g., wpapriv) and assign users that should be able to use wpa_supplicant into that group.

Create /var/run/wpa_priv directory for UNIX domain sockets and control user access by setting it accessible only for the wpapriv group:

mkdir /var/run/wpa_priv
chown root:wpapriv /var/run/wpa_priv
chmod 0750 /var/run/wpa_priv

Start wpa_priv as root (e.g., from system startup scripts) with the enabled interfaces configured on the command line:

wpa_priv -B -c /var/run/wpa_priv -P /var/run/wpa_priv.pid wext:wlan0

Run wpa_supplicant as non-root with a user that is in the wpapriv group:

wpa_supplicant -i ath0 -c wpa_supplicant.conf

-c ctrl path Specify the path to wpa_priv control directory (Default: /var/run/wpa_priv/).

-B Run as a daemon in the background.

-P file Set the location of the PID file.

driver:ifname [driver:ifname ...] The <driver> string dictates which of the supported wpa_supplicant driver backends is to be used. To get a list of supported driver types see wpa_supplicant help (e.g, wpa_supplicant -h). The driver backend supported by most good drivers is wext. The <ifname> string specifies which network interface is to be managed by wpa_supplicant (e.g., wlan0 or ath0). wpa_priv does not use the network interface before wpa_supplicant is started, so it is fine to include network interfaces that are not available at the time wpa_priv is started. wpa_priv can control multiple interfaces with one process, but it is also possible to run multiple wpa_priv processes at the same time, if desired.

wpa_supplicant(8)

wpa_supplicant is copyright (c) 2003-2007, Jouni Malinen <j@w1.fi> and contributors. All Rights Reserved.

This program is dual-licensed under both the GPL version 2 and BSD license. Either license may be used at your option.