WPA Supplicant
==============
Copyright (c) 2003-2005, Jouni Malinen <jkmaline@cc.hut.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. Please note that
some of the driver interface implementations (driver_*.c) may be
licensed under a different license.
License
-------
GPL v2:
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License version 2 as
published by the Free Software Foundation.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
(this copy of the license is in COPYING file)
Alternatively, this software may be distributed under the terms of BSD
license:
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
3. Neither the name(s) of the above-listed copyright holder(s) nor the
names of its contributors may be used to endorse or promote products
derived from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
Features
--------
Supported WPA/IEEE 802.11i features:
- WPA-PSK ("WPA-Personal")
- WPA with EAP (e.g., with RADIUS authentication server) ("WPA-Enterprise")
Following authentication methods are supported with an integrate IEEE 802.1X
Supplicant:
* EAP-TLS
* EAP-PEAP/MSCHAPv2 (both PEAPv0 and PEAPv1)
* EAP-PEAP/TLS (both PEAPv0 and PEAPv1)
* EAP-PEAP/GTC (both PEAPv0 and PEAPv1)
* EAP-PEAP/OTP (both PEAPv0 and PEAPv1)
* EAP-PEAP/MD5-Challenge (both PEAPv0 and PEAPv1)
* EAP-TTLS/EAP-MD5-Challenge
* EAP-TTLS/EAP-GTC
* EAP-TTLS/EAP-OTP
* EAP-TTLS/EAP-MSCHAPv2
* EAP-TTLS/EAP-TLS
* EAP-TTLS/MSCHAPv2
* EAP-TTLS/MSCHAP
* EAP-TTLS/PAP
* EAP-TTLS/CHAP
* EAP-SIM
* EAP-AKA
* EAP-PSK
* LEAP (note: requires special support from the driver for IEEE 802.11
authentication)
(following methods are supported, but since they do not generate keying
material, they cannot be used with WPA or IEEE 802.1X WEP keying)
* EAP-MD5-Challenge
* EAP-MSCHAPv2
* EAP-GTC
* EAP-OTP
Alternatively, an external program, e.g., Xsupplicant, can be used for EAP
authentication.
- key management for CCMP, TKIP, WEP104, WEP40
- RSN/WPA2 (IEEE 802.11i)
* pre-authentication
* PMKSA caching
Requirements
------------
Current hardware/software requirements:
- Linux kernel 2.4.x or 2.6.x with Linux Wireless Extensions v15 or newer
- FreeBSD 6-CURRENT
- Microsoft Windows with WinPcap (at least WinXP, may work with other versions)
- drivers:
Host AP driver for Prism2/2.5/3 (development snapshot/v0.2.x)
(http://hostap.epitest.fi/)
Driver need to be set in Managed mode ('iwconfig wlan0 mode managed').
Please note that station firmware version needs to be 1.7.0 or newer
to work in WPA mode.
Linuxant DriverLoader (http://www.linuxant.com/driverloader/)
with Windows NDIS driver for your wlan card supporting WPA.
Agere Systems Inc. Linux Driver
(http://www.agere.com/support/drivers/)
Please note that the driver interface file (driver_hermes.c) and
hardware specific include files are not included in the
wpa_supplicant distribution. You will need to copy these from the
source package of the Agere driver.
madwifi driver for cards based on Atheros chip set (ar521x)
(http://sourceforge.net/projects/madwifi/)
Please note that you will need to modify the wpa_supplicant .config
file to use the correct path for the madwifi driver root directory
(CFLAGS += -I../madwifi/wpa line in example defconfig).
ATMEL AT76C5XXx driver for USB and PCMCIA cards
(http://atmelwlandriver.sourceforge.net/).
Linux ndiswrapper (http://ndiswrapper.sourceforge.net/) with
Windows NDIS driver.
Broadcom wl.o driver
This is a generic Linux driver for Broadcom IEEE 802.11a/g cards.
However, it is proprietary driver that is not publicly available
except for couple of exceptions, mainly Broadcom-based APs/wireless
routers that use Linux. The driver binary can be downloaded, e.g.,
from Linksys support site (http://www.linksys.com/support/gpl.asp)
for Linksys WRT54G. The GPL tarball includes cross-compiler and
the needed header file, wlioctl.h, for compiling wpa_supplicant.
This driver support in wpa_supplicant is expected to work also with
other devices based on Broadcom driver (assuming the driver includes
client mode support).
Intel ipw2100 driver
(http://sourceforge.net/projects/ipw2100/)
Intel ipw2200 driver
(http://sourceforge.net/projects/ipw2200/)
In theory, any driver that supports Linux wireless extensions can be
used with IEEE 802.1X (i.e., not WPA) when using ap_scan=0 option in
configuration file.
BSD net80211 layer (e.g., Atheros driver)
At the moment, this is for FreeBSD 6-CURRENT branch.
Windows NDIS
The current Windows port requires WinPcap (http://winpcap.polito.it/).
See README-Windows.txt for more information.
wpa_supplicant was designed to be portable for different drivers and
operating systems. Hopefully, support for more wlan cards and OSes will be
added in the future. See developer.txt for more information about the
design of wpa_supplicant and porting to other drivers. One main goal
is to add full WPA/WPA2 support to Linux wireless extensions to allow
new drivers to be supported without having to implement new
driver-specific interface code in wpa_supplicant.
Optional libraries for layer2 packet processing:
- libpcap (tested with 0.7.2, most relatively recent versions assumed to work,
this is likely to be available with most distributions,
http://tcpdump.org/)
- libdnet (tested with v1.4, most versions assumed to work,
http://libdnet.sourceforge.net/)
These libraries are _not_ used in the default Linux build. Instead,
internal Linux specific implementation is used. libpcap/libdnet are
more portable and they can be used by adding CONFIG_DNET_PCAP=y into
.config. They may also be selected automatically for other operating
systems.
Optional libraries for EAP-TLS, EAP-PEAP, and EAP-TTLS:
- openssl (tested with 0.9.7c and 0.9.7d, assumed to work with most
relatively recent versions; this is likely to be available with most
distributions, http://www.openssl.org/)
This library is only needed when EAP-TLS, EAP-PEAP, or EAP-TTLS
support is enabled. WPA-PSK mode does not require this or EAPOL/EAP
implementation. A configuration file, .config, for compilation is
needed to enable IEEE 802.1X/EAPOL and EAP methods. Note that EAP-MD5,
EAP-GTC, EAP-OTP, and EAP-MSCHAPV2 cannot be used alone with WPA, so
they should only be enabled if testing the EAPOL/EAP state
machines. However, there can be used as inner authentication
algorithms with EAP-PEAP and EAP-TTLS.
See Building and installing section below for more detailed
information about the wpa_supplicant build time configuration.
WPA
---
The original security mechanism of IEEE 802.11 standard was not
designed to be strong and has proven to be insufficient for most
networks that require some kind of security. Task group I (Security)
of IEEE 802.11 working group (http://www.ieee802.org/11/) has worked
to address the flaws of the base standard and has in practice
completed its work in May 2004. The IEEE 802.11i amendment to the IEEE
802.11 standard was approved in June 2004 and this amendment is likely
to be published in July 2004.
Wi-Fi Alliance (http://www.wi-fi.org/) used a draft version of the
IEEE 802.11i work (draft 3.0) to define a subset of the security
enhancements that can be implemented with existing wlan hardware. This
is called Wi-Fi Protected Access<TM> (WPA). This has now become a
mandatory component of interoperability testing and certification done
by Wi-Fi Alliance. Wi-Fi provides information about WPA at its web
site (http://www.wi-fi.org/OpenSection/protected_access.asp).
IEEE 802.11 standard defined wired equivalent privacy (WEP) algorithm
for protecting wireless networks. WEP uses RC4 with 40-bit keys,
24-bit initialization vector (IV), and CRC32 to protect against packet
forgery. All these choices have proven to be insufficient: key space is
too small against current attacks, RC4 key scheduling is insufficient
(beginning of the pseudorandom stream should be skipped), IV space is
too small and IV reuse makes attacks easier, there is no replay
protection, and non-keyed authentication does not protect against bit
flipping packet data.
WPA is an intermediate solution for the security issues. It uses
Temporal Key Integrity Protocol (TKIP) to replace WEP. TKIP is a
compromise on strong security and possibility to use existing
hardware. It still uses RC4 for the encryption like WEP, but with
per-packet RC4 keys. In addition, it implements replay protection,
keyed packet authentication mechanism (Michael MIC).
Keys can be managed using two different mechanisms. WPA can either use
an external authentication server (e.g., RADIUS) and EAP just like
IEEE 802.1X is using or pre-shared keys without need for additional
servers. Wi-Fi calls these "WPA-Enterprise" and "WPA-Personal",
respectively. Both mechanisms will generate a master session key for
the Authenticator (AP) and Supplicant (client station).
WPA implements a new key handshake (4-Way Handshake and Group Key
Handshake) for generating and exchanging data encryption keys between
the Authenticator and Supplicant. This handshake is also used to
verify that both Authenticator and Supplicant know the master session
key. These handshakes are identical regardless of the selected key
management mechanism (only the method for generating master session
key changes).
IEEE 802.11i / WPA2
-------------------
The design for parts of IEEE 802.11i that were not included in WPA has
finished (May 2004) and this amendment to IEEE 802.11 was approved in
June 2004. Wi-Fi Alliance is using the final IEEE 802.11i as a new
version of WPA called WPA2. This includes, e.g., support for more
robust encryption algorithm (CCMP: AES in Counter mode with CBC-MAC)
to replace TKIP and optimizations for handoff (reduced number of
messages in initial key handshake, pre-authentication, and PMKSA caching).
Some wireless LAN vendors are already providing support for CCMP in
their WPA products. There is no "official" interoperability
certification for CCMP and/or mixed modes using both TKIP and CCMP, so
some interoperability issues can be expected even though many
combinations seem to be working with equipment from different vendors.
Certification for WPA2 is likely to start during the second half of
2004.
wpa_supplicant
--------------
wpa_supplicant is an implementation of the WPA Supplicant component,
i.e., the part that runs in the client stations. It implements WPA key
negotiation with a WPA Authenticator and EAP authentication with
Authentication Server. In addition, it controls the roaming and IEEE
802.11 authentication/association of the wlan driver.
wpa_supplicant is designed to be a "daemon" program that runs in the
background and acts as the backend component controlling the wireless
connection. wpa_supplicant supports separate frontend programs and an
example text-based frontend, wpa_cli, is included with wpa_supplicant.
Following steps are used when associating with an AP using WPA:
- wpa_supplicant requests the kernel driver to scan neighboring BSSes
- wpa_supplicant selects a BSS based on its configuration
- wpa_supplicant requests the kernel driver to associate with the chosen
BSS
- If WPA-EAP: integrated IEEE 802.1X Supplicant or external Xsupplicant
completes EAP authentication with the authentication server (proxied
by the Authenticator in the AP)
- If WPA-EAP: master key is received from the IEEE 802.1X Supplicant
- If WPA-PSK: wpa_supplicant uses PSK as the master session key
- wpa_supplicant completes WPA 4-Way Handshake and Group Key Handshake
with the Authenticator (AP)
- wpa_supplicant configures encryption keys for unicast and broadcast
- normal data packets can be transmitted and received
Building and installing
-----------------------
In order to be able to build wpa_supplicant, you will first need to
select which parts of it will be included. This is done by creating a
build time configuration file, .config, in the wpa_supplicant root
directory. Configuration options are text lines using following
format: CONFIG_<option>=y. Lines starting with # are considered
comments and are ignored. See defconfig file for example configuration
and list of available option.
The build time configuration can be used to select only the needed
features and limit the binary size and requirements for external
libraries. The main configuration parts are the selection of which
driver interfaces (e.g., hostap, madwifi, ..) and which authentication
methods (e.g., EAP-TLS, EAP-PEAP, ..) are included.
Following build time configuration options are used to control IEEE
802.1X/EAPOL and EAP state machines and all EAP methods. Including
TLS, PEAP, or TTLS will require linking wpa_supplicant with openssl
library for TLS implementation.
CONFIG_IEEE8021X_EAPOL=y
CONFIG_EAP_MD5=y
CONFIG_EAP_MSCHAPV2=y
CONFIG_EAP_TLS=y
CONFIG_EAP_PEAP=y
CONFIG_EAP_TTLS=y
CONFIG_EAP_GTC=y
CONFIG_EAP_OTP=y
CONFIG_EAP_SIM=y
CONFIG_EAP_AKA=y
CONFIG_EAP_PSK=y
CONFIG_EAP_LEAP=y
Following option can be used to include GSM SIM/USIM interface for GSM/UMTS
authentication algorithm (for EAP-SIM/EAP-AKA). This requires pcsc-lite
(http://www.linuxnet.com/) for smart card access.
CONFIG_PCSC=y
Following option can be used to replace the native Linux packet socket
interface with libpcap/libdnet.
CONFIG_DNET_PCAP=y
Following options can be added to .config to select which driver
interfaces are included. Prism54.org driver is not yet complete and
Hermes driver interface needs to be downloaded from Agere (see above).
Most Linux driver need to include CONFIG_WIRELESS_EXTENSION.
CONFIG_WIRELESS_EXTENSION=y
CONFIG_DRIVER_HOSTAP=y
CONFIG_DRIVER_PRISM54=y
CONFIG_DRIVER_HERMES=y
CONFIG_DRIVER_MADWIFI=y
CONFIG_DRIVER_ATMEL=y
CONFIG_DRIVER_WEXT=y
CONFIG_DRIVER_NDISWRAPPER=y
CONFIG_DRIVER_BROADCOM=y
CONFIG_DRIVER_IPW=y
CONFIG_DRIVER_BSD=y
CONFIG_DRIVER_NDIS=y
Following example includes all features and driver interfaces that are
included in the wpa_supplicant package:
CONFIG_DRIVER_HOSTAP=y
CONFIG_DRIVER_PRISM54=y
CONFIG_DRIVER_HERMES=y
CONFIG_DRIVER_MADWIFI=y
CONFIG_DRIVER_ATMEL=y
CONFIG_DRIVER_WEXT=y
CONFIG_DRIVER_NDISWRAPPER=y
CONFIG_DRIVER_BROADCOM=y
CONFIG_DRIVER_IPW=y
CONFIG_DRIVER_BSD=y
CONFIG_DRIVER_NDIS=y
CONFIG_WIRELESS_EXTENSION=y
CONFIG_IEEE8021X_EAPOL=y
CONFIG_EAP_MD5=y
CONFIG_EAP_MSCHAPV2=y
CONFIG_EAP_TLS=y
CONFIG_EAP_PEAP=y
CONFIG_EAP_TTLS=y
CONFIG_EAP_GTC=y
CONFIG_EAP_OTP=y
CONFIG_EAP_SIM=y
CONFIG_EAP_AKA=y
CONFIG_EAP_PSK=y
CONFIG_EAP_LEAP=y
CONFIG_PCSC=y
EAP-PEAP and EAP-TTLS will automatically include configured EAP
methods (MD5, OTP, GTC, MSCHAPV2) for inner authentication selection.
After you have created a configuration file, you can build
wpa_supplicant and wpa_cli with 'make' command. You may then install
the binaries to a suitable system directory, e.g., /usr/local/bin.
Example commands:
# build wpa_supplicant and wpa_cli
make
# install binaries (this may need root privileges)
cp wpa_cli wpa_supplicant /usr/local/bin
You will need to make a configuration file, e.g.,
/etc/wpa_supplicant.conf, with network configuration for the networks
you are going to use. Configuration file section below includes
explanation fo the configuration file format and includes various
examples. Once the configuration is ready, you can test whether the
configuration work by first running wpa_supplicant with following
command to start it on foreground with debugging enabled:
wpa_supplicant -iwlan0 -c/etc/wpa_supplicant.conf -d
Assuming everything goes fine, you can start using following command
to start wpa_supplicant on background without debugging:
wpa_supplicant -iwlan0 -c/etc/wpa_supplicant.conf -B
Please note that if you included more than one driver interface in the
build time configuration (.config), you may need to specify which
interface to use by including -D<driver name> option on the command
line. See following section for more details on command line options
for wpa_supplicant.
Command line options
--------------------
usage:
wpa_supplicant [-BddehLqqvw] -i<ifname> -c<config file> [-D<driver>] \
[-N -i<ifname> -c<conf> [-D<driver>] ...]
options:
-B = run daemon in the background
-d = increase debugging verbosity (-dd even more)
-K = include keys (passwords, etc.) in debug output
-t = include timestamp in debug messages
-e = use external IEEE 802.1X Supplicant (e.g., xsupplicant)
(this disables the internal Supplicant)
-h = show this help text
-L = show license (GPL and BSD)
-q = decrease debugging verbosity (-qq even less)
-v = show version
-w = wait for interface to be added, if needed
-N = start describing new interface
drivers:
hostap = Host AP driver (Intersil Prism2/2.5/3) [default]
(this can also be used with Linuxant DriverLoader)
prism54 = Prism54.org driver (Intersil Prism GT/Duette/Indigo)
not yet fully implemented
hermes = Agere Systems Inc. driver (Hermes-I/Hermes-II)
madwifi = MADWIFI 802.11 support (Atheros, etc.)
atmel = ATMEL AT76C5XXx (USB, PCMCIA)
wext = Linux wireless extensions (generic)
ndiswrapper = Linux ndiswrapper
broadcom = Broadcom wl.o driver
ipw = Intel ipw2100/2200 driver
bsd = BSD 802.11 support (Atheros, etc.)
ndis = Windows NDIS driver
In most common cases, wpa_supplicant is started with
wpa_supplicant -Bw -c/etc/wpa_supplicant.conf -iwlan0
This makes the process fork into background and wait for the wlan0
interface if it is not available at startup time.
The easiest way to debug problems, and to get debug log for bug
reports, is to start wpa_supplicant on foreground with debugging
enabled:
wpa_supplicant -c/etc/wpa_supplicant.conf -iwlan0 -d
wpa_supplicant can control multiple interfaces (radios) either by
running one process for each interface separately or by running just
one process and list of options at command line. Each interface is
separated with -N argument. As an example, following command would
start wpa_supplicant for two interfaces:
wpa_supplicant \
-c wpa1.conf -i wlan0 -D hostap -N \
-c wpa2.conf -i ath0 -D madwifi
Configuration file
------------------
wpa_supplicant is configured using a text file that lists all accepted
networks and security policies, including pre-shared keys. See
example configuration file, wpa_supplicant.conf, for detailed
information about the configuration format and supported fields.
Changes to configuration file can be reloaded be sending SIGHUP signal
to wpa_supplicant ('killall -HUP wpa_supplicant'). Similarly,
reloading can be triggered with 'wpa_cli reconfigure' command.
Configuration file can include one or more network blocks, e.g., one
for each used SSID. wpa_supplicant will automatically select the best
betwork based on the order of network blocks in the configuration
file, network security level (WPA/WPA2 is prefered), and signal
strength.
Example configuration files for some common configurations:
1) WPA-Personal (PSK) as home network and WPA-Enterprise with EAP-TLS as work
network
# allow frontend (e.g., wpa_cli) to be used by all users in 'wheel' group
ctrl_interface=/var/run/wpa_supplicant
ctrl_interface_group=wheel
#
# home network; allow all valid ciphers
network={
ssid="home"
scan_ssid=1
key_mgmt=WPA-PSK
psk="very secret passphrase"
}
#
# work network; use EAP-TLS with WPA; allow only CCMP and TKIP ciphers
network={
ssid="work"
scan_ssid=1
key_mgmt=WPA-EAP
pairwise=CCMP TKIP
group=CCMP TKIP
eap=TLS
identity="user@example.com"
ca_cert="/etc/cert/ca.pem"
client_cert="/etc/cert/user.pem"
private_key="/etc/cert/user.prv"
private_key_passwd="password"
}
2) WPA-RADIUS/EAP-PEAP/MSCHAPv2 with RADIUS servers that use old peaplabel
(e.g., Funk Odyssey and SBR, Meetinghouse Aegis, Interlink RAD-Series)
ctrl_interface=/var/run/wpa_supplicant
ctrl_interface_group=wheel
network={
ssid="example"
scan_ssid=1
key_mgmt=WPA-EAP
eap=PEAP
identity="user@example.com"
password="foobar"
ca_cert="/etc/cert/ca.pem"
phase1="peaplabel=0"
phase2="auth=MSCHAPV2"
}
3) EAP-TTLS/EAP-MD5-Challenge configuration with anonymous identity for the
unencrypted use. Real identity is sent only within an encrypted TLS tunnel.
ctrl_interface=/var/run/wpa_supplicant
ctrl_interface_group=wheel
network={
ssid="example"
scan_ssid=1
key_mgmt=WPA-EAP
eap=TTLS
identity="user@example.com"
anonymous_identity="anonymous@example.com"
password="foobar"
ca_cert="/etc/cert/ca.pem"
phase2="auth=MD5"
}
4) IEEE 802.1X (i.e., no WPA) with dynamic WEP keys (require both unicast and
broadcast); use EAP-TLS for authentication
ctrl_interface=/var/run/wpa_supplicant
ctrl_interface_group=wheel
network={
ssid="1x-test"
scan_ssid=1
key_mgmt=IEEE8021X
eap=TLS
identity="user@example.com"
ca_cert="/etc/cert/ca.pem"
client_cert="/etc/cert/user.pem"
private_key="/etc/cert/user.prv"
private_key_passwd="password"
eapol_flags=3
}
5) Catch all example that allows more or less all configuration modes. The
configuration options are used based on what security policy is used in the
selected SSID. This is mostly for testing and is not recommended for normal
use.
ctrl_interface=/var/run/wpa_supplicant
ctrl_interface_group=wheel
network={
ssid="example"
scan_ssid=1
key_mgmt=WPA-EAP WPA-PSK IEEE8021X NONE
pairwise=CCMP TKIP
group=CCMP TKIP WEP104 WEP40
psk="very secret passphrase"
eap=TTLS PEAP TLS
identity="user@example.com"
password="foobar"
ca_cert="/etc/cert/ca.pem"
client_cert="/etc/cert/user.pem"
private_key="/etc/cert/user.prv"
private_key_passwd="password"
phase1="peaplabel=0"
ca_cert2="/etc/cert/ca2.pem"
client_cert2="/etc/cer/user.pem"
private_key2="/etc/cer/user.prv"
private_key2_passwd="password"
}
Certificates
------------
Some EAP authentication methods require use of certificates. EAP-TLS
uses both server side and client certificates whereas EAP-PEAP and
EAP-TTLS only require the server side certificate. When client
certificate is used, a matching private key file has to also be
included in configuration. If the private key uses a passphrase, this
has to be configured in wpa_supplicant.conf ("private_key_passwd").
wpa_supplicant supports X.509 certificates in PEM and DER
formats. User certificate and private key can be included in the same
file.
If the user certificate and private key is received in PKCS#12/PFX
format, they need to be converted to suitable PEM/DER format for
wpa_supplicant. This can be done, e.g., with following commands:
# convert client certificate and private key to PEM format
openssl pkcs12 -in example.pfx -out user.pem -clcerts
# convert CA certificate (if included in PFX file) to PEM format
openssl pkcs12 -in example.pfx -out ca.pem -cacerts -nokeys
wpa_cli
-------
wpa_cli is a text-based frontend program for interacting with
wpa_supplicant. It is used to query current status, change
configuration, trigger events, and request interactive user input.
wpa_cli can show the current authentication status, selected security
mode, dot11 and dot1x MIBs, etc. In addition, it can configuring some
variables like EAPOL state machine parameters and trigger events like
reassociation and IEEE 802.1X logoff/logon. wpa_cli provides a user
interface to request authentication information, like username and
password, if these are not included in the configuration. This can be
used to implement, e.g., one-time-passwords or generic token card
authentication where the authentication is based on a
challenge-response that uses an external device for generating the
response.
The control interface of wpa_supplicant can be configured to allow
non-root user access (ctrl_interface_group in the configuration
file). This makes it possible to run wpa_cli with a normal user
account.
wpa_cli supports two modes: interactive and command line. Both modes
share the same command set and the main difference is in interactive
mode providing access to unsolicited messages (event messages,
username/password requests).
Interactive mode is started when wpa_cli is executed without including
the command as a command line parameter. Commands are then entered on
the wpa_cli prompt. In command line mode, the same commands are
entered as command line arguments for wpa_cli.
Interactive authentication parameters request
When wpa_supplicant need authentication parameters, like username and
password, which are not present in the configuration file, it sends a
request message to all attached frontend programs, e.g., wpa_cli in
interactive mode. wpa_cli shows these requests with
"CTRL-REQ-<type>-<id>:<text>" prefix. <type> is IDENTITY, PASSWORD, or
OTP (one-time-password). <id> is a unique identifier for the current
network. <text> is description of the request. In case of OTP request,
it includes the challenge from the authentication server.
The reply to these requests can be given with 'identity', 'password',
and 'otp' commands. <id> needs to be copied from the the matching
request. 'password' and 'otp' commands can be used regardless of
whether the request was for PASSWORD or OTP. The main difference
between these two commands is that values given with 'password' are
remembered as long as wpa_supplicant is running whereas values given
with 'otp' are used only once and then forgotten, i.e., wpa_supplicant
will ask frontend for a new value for every use. This can be used to
implement one-time-password lists and generic token card -based
authentication.
Example request for password and a matching reply:
CTRL-REQ-PASSWORD-1:Password needed for SSID foobar
> password 1 mysecretpassword
Example request for generic token card challenge-response:
CTRL-REQ-OTP-2:Challenge 1235663 needed for SSID foobar
> otp 2 9876
wpa_cli commands
status = get current WPA/EAPOL/EAP status
mib = get MIB variables (dot1x, dot11)
help = show this usage help
interface [ifname] = show interfaces/select interface
level <debug level> = change debug level
license = show full wpa_cli license
logoff = IEEE 802.1X EAPOL state machine logoff
logon = IEEE 802.1X EAPOL state machine logon
set = set variables (shows list of variables when run without arguments)
pmksa = show PMKSA cache
reassociate = force reassociation
reconfigure = force wpa_supplicant to re-read its configuration file
preauthenticate <BSSID> = force preauthentication
identity <network id> <identity> = configure identity for an SSID
password <network id> <password> = configure password for an SSID
otp <network id> <password> = configure one-time-password for an SSID
terminate = terminate wpa_supplicant
quit = exit wpa_cli
Integrating with pcmcia-cs/cardmgr scripts
------------------------------------------
wpa_supplicant needs to be running when using a wireless network with
WPA. It can be started either from system startup scripts or from
pcmcia-cs/cardmgr scripts (when using PC Cards). WPA handshake must be
completed before data frames can be exchanged, so wpa_supplicant
should be started before DHCP client.
Command line option '-w' can be used if wpa_supplicant is started
before the wireless LAN interface is present (e.g., before inserting
the PC Card) or is not yet up.
For example, following small changes to pcmcia-cs scripts can be used
to enable WPA support:
Add MODE="Managed" and WPA="y" to the network scheme in
/etc/pcmcia/wireless.opts.
Add the following block to the end of 'start' action handler in
/etc/pcmcia/wireless:
if [ "$WPA" = "y" -a -x /usr/local/bin/wpa_supplicant ]; then
/usr/local/bin/wpa_supplicant -Bw -c/etc/wpa_supplicant.conf \
-i$DEVICE
fi
Add the following block to the end of 'stop' action handler (may need
to be separated from other actions) in /etc/pcmcia/wireless:
if [ "$WPA" = "y" -a -x /usr/local/bin/wpa_supplicant ]; then
killall wpa_supplicant
fi
This will make cardmgr start wpa_supplicant when the card is plugged
in. wpa_supplicant will wait until the interface is set up--either
when a static IP address is configured or when DHCP client is
started--and will then negotiate keys with the AP.
Optional integration with Xsupplicant
-------------------------------------
wpa_supplicant has an integrated IEEE 802.1X Supplicant that supports
most commonly used EAP methods. In addition, wpa_supplicant has an
experimental interface for integrating it with Xsupplicant
(http://www.open1x.org/) for the WPA with EAP authentication.
When using WPA-EAP, both wpa_supplicant and Xsupplicant must be
configured with the network security policy. See Xsupplicant documents
for information about its configuration. Please also note, that a new
command line option -W (enable WPA) must be used when starting
xsupplicant.
Example configuration for xsupplicant:
network_list = all
default_netname = jkm
jkm
{
type = wireless
allow_types = eap_peap
identity = <BEGIN_ID>jkm<END_ID>
eap-peap {
random_file = /dev/urandom
root_cert = /home/jkm/CA.pem
chunk_size = 1398
allow_types = eap_mschapv2
eap-mschapv2 {
username = <BEGIN_UNAME>jkm<END_UNAME>
password = <BEGIN_PASS>jkm<END_PASS>
}
}
}
Example configuration for wpa_supplicant:
network={
ssid="jkm"
key_mgmt=WPA-EAP
}
Both wpa_supplicant and xsupplicant need to be started. Please remember
to add '-W' option for xsupplicant in order to provide keying material
for wpa_supplicant and '-e' option for wpa_supplicant to disable internal
IEEE 802.1X implementation.
wpa_supplicant -iwlan0 -cwpa_supplicant.conf -e
xsupplicant -iwlan0 -cxsupplicant.conf -W
