4 Copyright (c) 2003-2009, Jouni Malinen <j@w1.fi> and contributors
7 This program is dual-licensed under both the GPL version 2 and BSD
8 license. Either license may be used at your option.
17 This program is free software; you can redistribute it and/or modify
18 it under the terms of the GNU General Public License version 2 as
19 published by the Free Software Foundation.
21 This program is distributed in the hope that it will be useful,
22 but WITHOUT ANY WARRANTY; without even the implied warranty of
23 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
24 GNU General Public License for more details.
26 You should have received a copy of the GNU General Public License
27 along with this program; if not, write to the Free Software
28 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
30 (this copy of the license is in COPYING file)
33 Alternatively, this software may be distributed, used, and modified
34 under the terms of BSD license:
36 Redistribution and use in source and binary forms, with or without
37 modification, are permitted provided that the following conditions are
40 1. Redistributions of source code must retain the above copyright
41 notice, this list of conditions and the following disclaimer.
43 2. Redistributions in binary form must reproduce the above copyright
44 notice, this list of conditions and the following disclaimer in the
45 documentation and/or other materials provided with the distribution.
47 3. Neither the name(s) of the above-listed copyright holder(s) nor the
48 names of its contributors may be used to endorse or promote products
49 derived from this software without specific prior written permission.
51 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
52 "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
53 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
54 A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
55 OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
56 SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
57 LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
58 DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
59 THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
60 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
61 OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
68 Supported WPA/IEEE 802.11i features:
69 - WPA-PSK ("WPA-Personal")
70 - WPA with EAP (e.g., with RADIUS authentication server) ("WPA-Enterprise")
71 Following authentication methods are supported with an integrate IEEE 802.1X
74 * EAP-PEAP/MSCHAPv2 (both PEAPv0 and PEAPv1)
75 * EAP-PEAP/TLS (both PEAPv0 and PEAPv1)
76 * EAP-PEAP/GTC (both PEAPv0 and PEAPv1)
77 * EAP-PEAP/OTP (both PEAPv0 and PEAPv1)
78 * EAP-PEAP/MD5-Challenge (both PEAPv0 and PEAPv1)
79 * EAP-TTLS/EAP-MD5-Challenge
82 * EAP-TTLS/EAP-MSCHAPv2
95 * LEAP (note: requires special support from the driver for IEEE 802.11
97 (following methods are supported, but since they do not generate keying
98 material, they cannot be used with WPA or IEEE 802.1X WEP keying)
103 - key management for CCMP, TKIP, WEP104, WEP40
104 - RSN/WPA2 (IEEE 802.11i)
108 Supported TLS/crypto libraries:
112 Internal TLS/crypto implementation (optional):
113 - can be used in place of an external TLS/crypto library
115 - X.509 certificate processing
120 - minimal size (ca. 50 kB binary, parts of which are already needed for WPA;
121 TLSv1/X.509/ASN.1/RSA/bignum parts are about 25 kB on x86)
127 Current hardware/software requirements:
128 - Linux kernel 2.4.x or 2.6.x with Linux Wireless Extensions v15 or newer
131 - Microsoft Windows with WinPcap (at least WinXP, may work with other versions)
133 Linux drivers that support WPA/WPA2 configuration with the generic
134 Linux wireless extensions (WE-18 or newer). Even though there are
135 number of driver specific interface included in wpa_supplicant, please
136 note that Linux drivers are moving to use generic wireless extensions
137 and driver_wext (-Dwext on wpa_supplicant command line) should be the
138 default option to start with before falling back to driver specific
141 Host AP driver for Prism2/2.5/3 (development snapshot/v0.2.x)
142 (http://hostap.epitest.fi/)
143 Driver need to be set in Managed mode ('iwconfig wlan0 mode managed').
144 Please note that station firmware version needs to be 1.7.0 or newer
147 Linuxant DriverLoader (http://www.linuxant.com/driverloader/)
148 with Windows NDIS driver for your wlan card supporting WPA.
150 Agere Systems Inc. Linux Driver
151 (http://www.agere.com/support/drivers/)
152 Please note that the driver interface file (driver_hermes.c) and
153 hardware specific include files are not included in the
154 wpa_supplicant distribution. You will need to copy these from the
155 source package of the Agere driver.
157 madwifi driver for cards based on Atheros chip set (ar521x)
158 (http://sourceforge.net/projects/madwifi/)
159 Please note that you will need to modify the wpa_supplicant .config
160 file to use the correct path for the madwifi driver root directory
161 (CFLAGS += -I../madwifi/wpa line in example defconfig).
163 ATMEL AT76C5XXx driver for USB and PCMCIA cards
164 (http://atmelwlandriver.sourceforge.net/).
166 Linux ndiswrapper (http://ndiswrapper.sourceforge.net/) with
169 Broadcom wl.o driver (old version only)
170 This is a generic Linux driver for Broadcom IEEE 802.11a/g cards.
171 However, it is proprietary driver that is not publicly available
172 except for couple of exceptions, mainly Broadcom-based APs/wireless
173 routers that use Linux. The driver binary can be downloaded, e.g.,
174 from Linksys support site (http://www.linksys.com/support/gpl.asp)
175 for Linksys WRT54G. The GPL tarball includes cross-compiler and
176 the needed header file, wlioctl.h, for compiling wpa_supplicant.
177 This driver support in wpa_supplicant is expected to work also with
178 other devices based on Broadcom driver (assuming the driver includes
179 client mode support). Please note that the newer Broadcom driver
180 ("hybrid Linux driver") supports Linux wireless extensions and does
181 not need (or even work) with the specific driver wrapper. Use -Dwext
185 (http://sourceforge.net/projects/ipw2100/)
188 (http://sourceforge.net/projects/ipw2200/)
190 In theory, any driver that supports Linux wireless extensions can be
191 used with IEEE 802.1X (i.e., not WPA) when using ap_scan=0 option in
194 Wired Ethernet drivers (with ap_scan=0)
196 BSD net80211 layer (e.g., Atheros driver)
197 At the moment, this is for FreeBSD 6-CURRENT branch and NetBSD-current.
200 The current Windows port requires WinPcap (http://winpcap.polito.it/).
201 See README-Windows.txt for more information.
203 wpa_supplicant was designed to be portable for different drivers and
204 operating systems. Hopefully, support for more wlan cards and OSes will be
205 added in the future. See developer's documentation
206 (http://hostap.epitest.fi/wpa_supplicant/devel/) for more information about the
207 design of wpa_supplicant and porting to other drivers. One main goal
208 is to add full WPA/WPA2 support to Linux wireless extensions to allow
209 new drivers to be supported without having to implement new
210 driver-specific interface code in wpa_supplicant.
212 Optional libraries for layer2 packet processing:
213 - libpcap (tested with 0.7.2, most relatively recent versions assumed to work,
214 this is likely to be available with most distributions,
216 - libdnet (tested with v1.4, most versions assumed to work,
217 http://libdnet.sourceforge.net/)
219 These libraries are _not_ used in the default Linux build. Instead,
220 internal Linux specific implementation is used. libpcap/libdnet are
221 more portable and they can be used by adding CONFIG_L2_PACKET=pcap into
222 .config. They may also be selected automatically for other operating
223 systems. In case of Windows builds, WinPcap is used by default
224 (CONFIG_L2_PACKET=winpcap).
227 Optional libraries for EAP-TLS, EAP-PEAP, and EAP-TTLS:
228 - OpenSSL (tested with 0.9.7c and 0.9.7d, and 0.9.8 versions; assumed to
229 work with most relatively recent versions; this is likely to be
230 available with most distributions, http://www.openssl.org/)
232 - internal TLSv1 implementation
234 TLS options for EAP-FAST:
235 - OpenSSL 0.9.8d _with_ openssl-0.9.8d-tls-extensions.patch applied
236 (i.e., the default OpenSSL package does not include support for
237 extensions needed for EAP-FAST)
238 - internal TLSv1 implementation
240 One of these libraries is needed when EAP-TLS, EAP-PEAP, EAP-TTLS, or
241 EAP-FAST support is enabled. WPA-PSK mode does not require this or EAPOL/EAP
242 implementation. A configuration file, .config, for compilation is
243 needed to enable IEEE 802.1X/EAPOL and EAP methods. Note that EAP-MD5,
244 EAP-GTC, EAP-OTP, and EAP-MSCHAPV2 cannot be used alone with WPA, so
245 they should only be enabled if testing the EAPOL/EAP state
246 machines. However, there can be used as inner authentication
247 algorithms with EAP-PEAP and EAP-TTLS.
249 See Building and installing section below for more detailed
250 information about the wpa_supplicant build time configuration.
257 The original security mechanism of IEEE 802.11 standard was not
258 designed to be strong and has proven to be insufficient for most
259 networks that require some kind of security. Task group I (Security)
260 of IEEE 802.11 working group (http://www.ieee802.org/11/) has worked
261 to address the flaws of the base standard and has in practice
262 completed its work in May 2004. The IEEE 802.11i amendment to the IEEE
263 802.11 standard was approved in June 2004 and published in July 2004.
265 Wi-Fi Alliance (http://www.wi-fi.org/) used a draft version of the
266 IEEE 802.11i work (draft 3.0) to define a subset of the security
267 enhancements that can be implemented with existing wlan hardware. This
268 is called Wi-Fi Protected Access<TM> (WPA). This has now become a
269 mandatory component of interoperability testing and certification done
270 by Wi-Fi Alliance. Wi-Fi provides information about WPA at its web
271 site (http://www.wi-fi.org/OpenSection/protected_access.asp).
273 IEEE 802.11 standard defined wired equivalent privacy (WEP) algorithm
274 for protecting wireless networks. WEP uses RC4 with 40-bit keys,
275 24-bit initialization vector (IV), and CRC32 to protect against packet
276 forgery. All these choices have proven to be insufficient: key space is
277 too small against current attacks, RC4 key scheduling is insufficient
278 (beginning of the pseudorandom stream should be skipped), IV space is
279 too small and IV reuse makes attacks easier, there is no replay
280 protection, and non-keyed authentication does not protect against bit
281 flipping packet data.
283 WPA is an intermediate solution for the security issues. It uses
284 Temporal Key Integrity Protocol (TKIP) to replace WEP. TKIP is a
285 compromise on strong security and possibility to use existing
286 hardware. It still uses RC4 for the encryption like WEP, but with
287 per-packet RC4 keys. In addition, it implements replay protection,
288 keyed packet authentication mechanism (Michael MIC).
290 Keys can be managed using two different mechanisms. WPA can either use
291 an external authentication server (e.g., RADIUS) and EAP just like
292 IEEE 802.1X is using or pre-shared keys without need for additional
293 servers. Wi-Fi calls these "WPA-Enterprise" and "WPA-Personal",
294 respectively. Both mechanisms will generate a master session key for
295 the Authenticator (AP) and Supplicant (client station).
297 WPA implements a new key handshake (4-Way Handshake and Group Key
298 Handshake) for generating and exchanging data encryption keys between
299 the Authenticator and Supplicant. This handshake is also used to
300 verify that both Authenticator and Supplicant know the master session
301 key. These handshakes are identical regardless of the selected key
302 management mechanism (only the method for generating master session
310 The design for parts of IEEE 802.11i that were not included in WPA has
311 finished (May 2004) and this amendment to IEEE 802.11 was approved in
312 June 2004. Wi-Fi Alliance is using the final IEEE 802.11i as a new
313 version of WPA called WPA2. This includes, e.g., support for more
314 robust encryption algorithm (CCMP: AES in Counter mode with CBC-MAC)
315 to replace TKIP and optimizations for handoff (reduced number of
316 messages in initial key handshake, pre-authentication, and PMKSA caching).
323 wpa_supplicant is an implementation of the WPA Supplicant component,
324 i.e., the part that runs in the client stations. It implements WPA key
325 negotiation with a WPA Authenticator and EAP authentication with
326 Authentication Server. In addition, it controls the roaming and IEEE
327 802.11 authentication/association of the wlan driver.
329 wpa_supplicant is designed to be a "daemon" program that runs in the
330 background and acts as the backend component controlling the wireless
331 connection. wpa_supplicant supports separate frontend programs and an
332 example text-based frontend, wpa_cli, is included with wpa_supplicant.
334 Following steps are used when associating with an AP using WPA:
336 - wpa_supplicant requests the kernel driver to scan neighboring BSSes
337 - wpa_supplicant selects a BSS based on its configuration
338 - wpa_supplicant requests the kernel driver to associate with the chosen
340 - If WPA-EAP: integrated IEEE 802.1X Supplicant completes EAP
341 authentication with the authentication server (proxied by the
342 Authenticator in the AP)
343 - If WPA-EAP: master key is received from the IEEE 802.1X Supplicant
344 - If WPA-PSK: wpa_supplicant uses PSK as the master session key
345 - wpa_supplicant completes WPA 4-Way Handshake and Group Key Handshake
346 with the Authenticator (AP)
347 - wpa_supplicant configures encryption keys for unicast and broadcast
348 - normal data packets can be transmitted and received
352 Building and installing
353 -----------------------
355 In order to be able to build wpa_supplicant, you will first need to
356 select which parts of it will be included. This is done by creating a
357 build time configuration file, .config, in the wpa_supplicant root
358 directory. Configuration options are text lines using following
359 format: CONFIG_<option>=y. Lines starting with # are considered
360 comments and are ignored. See defconfig file for an example configuration
361 and a list of available options and additional notes.
363 The build time configuration can be used to select only the needed
364 features and limit the binary size and requirements for external
365 libraries. The main configuration parts are the selection of which
366 driver interfaces (e.g., hostap, madwifi, ..) and which authentication
367 methods (e.g., EAP-TLS, EAP-PEAP, ..) are included.
369 Following build time configuration options are used to control IEEE
370 802.1X/EAPOL and EAP state machines and all EAP methods. Including
371 TLS, PEAP, or TTLS will require linking wpa_supplicant with OpenSSL
372 library for TLS implementation. Alternatively, GnuTLS or the internal
373 TLSv1 implementation can be used for TLS functionaly.
375 CONFIG_IEEE8021X_EAPOL=y
377 CONFIG_EAP_MSCHAPV2=y
392 Following option can be used to include GSM SIM/USIM interface for GSM/UMTS
393 authentication algorithm (for EAP-SIM/EAP-AKA). This requires pcsc-lite
394 (http://www.linuxnet.com/) for smart card access.
398 Following options can be added to .config to select which driver
399 interfaces are included. Hermes driver interface needs to be downloaded
400 from Agere (see above). CONFIG_WIRELESS_EXTENSION will be used
401 automatically if any of the selected drivers need it.
403 CONFIG_WIRELESS_EXTENSION=y
404 CONFIG_DRIVER_HOSTAP=y
405 CONFIG_DRIVER_HERMES=y
406 CONFIG_DRIVER_MADWIFI=y
407 CONFIG_DRIVER_ATMEL=y
409 CONFIG_DRIVER_RALINK=y
410 CONFIG_DRIVER_NDISWRAPPER=y
411 CONFIG_DRIVER_BROADCOM=y
416 Following example includes all features and driver interfaces that are
417 included in the wpa_supplicant package:
419 CONFIG_DRIVER_HOSTAP=y
420 CONFIG_DRIVER_HERMES=y
421 CONFIG_DRIVER_MADWIFI=y
422 CONFIG_DRIVER_ATMEL=y
424 CONFIG_DRIVER_NDISWRAPPER=y
425 CONFIG_DRIVER_BROADCOM=y
429 CONFIG_WIRELESS_EXTENSION=y
430 CONFIG_IEEE8021X_EAPOL=y
432 CONFIG_EAP_MSCHAPV2=y
448 EAP-PEAP and EAP-TTLS will automatically include configured EAP
449 methods (MD5, OTP, GTC, MSCHAPV2) for inner authentication selection.
452 After you have created a configuration file, you can build
453 wpa_supplicant and wpa_cli with 'make' command. You may then install
454 the binaries to a suitable system directory, e.g., /usr/local/bin.
458 # build wpa_supplicant and wpa_cli
460 # install binaries (this may need root privileges)
461 cp wpa_cli wpa_supplicant /usr/local/bin
464 You will need to make a configuration file, e.g.,
465 /etc/wpa_supplicant.conf, with network configuration for the networks
466 you are going to use. Configuration file section below includes
467 explanation fo the configuration file format and includes various
468 examples. Once the configuration is ready, you can test whether the
469 configuration work by first running wpa_supplicant with following
470 command to start it on foreground with debugging enabled:
472 wpa_supplicant -iwlan0 -c/etc/wpa_supplicant.conf -d
474 Assuming everything goes fine, you can start using following command
475 to start wpa_supplicant on background without debugging:
477 wpa_supplicant -iwlan0 -c/etc/wpa_supplicant.conf -B
479 Please note that if you included more than one driver interface in the
480 build time configuration (.config), you may need to specify which
481 interface to use by including -D<driver name> option on the command
482 line. See following section for more details on command line options
491 wpa_supplicant [-BddfhKLqqtuvwW] [-P<pid file>] [-g<global ctrl>] \
492 -i<ifname> -c<config file> [-C<ctrl>] [-D<driver>] [-p<driver_param>] \
493 [-b<br_ifname> [-N -i<ifname> -c<conf> [-C<ctrl>] [-D<driver>] \
494 [-p<driver_param>] [-b<br_ifname>] ...]
497 -b = optional bridge interface name
498 -B = run daemon in the background
499 -c = Configuration file
500 -C = ctrl_interface parameter (only used if -c is not)
502 -d = increase debugging verbosity (-dd even more)
504 -f = Log output to default log location (normally /tmp)
505 -g = global ctrl_interface
506 -K = include keys (passwords, etc.) in debug output
507 -t = include timestamp in debug messages
508 -h = show this help text
509 -L = show license (GPL and BSD)
510 -p = driver parameters
512 -q = decrease debugging verbosity (-qq even less)
513 -u = enable DBus control interface
515 -w = wait for interface to be added, if needed
516 -W = wait for a control interface monitor before starting
517 -N = start describing new interface
520 hostap = Host AP driver (Intersil Prism2/2.5/3) [default]
521 (this can also be used with Linuxant DriverLoader)
522 hermes = Agere Systems Inc. driver (Hermes-I/Hermes-II)
523 madwifi = MADWIFI 802.11 support (Atheros, etc.)
524 atmel = ATMEL AT76C5XXx (USB, PCMCIA)
525 wext = Linux wireless extensions (generic)
526 ralink = Ralink Client driver
527 ndiswrapper = Linux ndiswrapper
528 broadcom = Broadcom wl.o driver
529 ipw = Intel ipw2100/2200 driver (old; use wext with Linux 2.6.13 or newer)
530 wired = wpa_supplicant wired Ethernet driver
531 roboswitch = wpa_supplicant Broadcom switch driver
532 bsd = BSD 802.11 support (Atheros, etc.)
533 ndis = Windows NDIS driver
535 In most common cases, wpa_supplicant is started with
537 wpa_supplicant -B -c/etc/wpa_supplicant.conf -iwlan0
539 This makes the process fork into background.
541 The easiest way to debug problems, and to get debug log for bug
542 reports, is to start wpa_supplicant on foreground with debugging
545 wpa_supplicant -c/etc/wpa_supplicant.conf -iwlan0 -d
548 wpa_supplicant can control multiple interfaces (radios) either by
549 running one process for each interface separately or by running just
550 one process and list of options at command line. Each interface is
551 separated with -N argument. As an example, following command would
552 start wpa_supplicant for two interfaces:
555 -c wpa1.conf -i wlan0 -D hostap -N \
556 -c wpa2.conf -i ath0 -D madwifi
559 If the interface is added in a Linux bridge (e.g., br0), the bridge
560 interface needs to be configured to wpa_supplicant in addition to the
563 wpa_supplicant -cw.conf -Dmadwifi -iath0 -bbr0
569 wpa_supplicant is configured using a text file that lists all accepted
570 networks and security policies, including pre-shared keys. See
571 example configuration file, wpa_supplicant.conf, for detailed
572 information about the configuration format and supported fields.
574 Changes to configuration file can be reloaded be sending SIGHUP signal
575 to wpa_supplicant ('killall -HUP wpa_supplicant'). Similarly,
576 reloading can be triggered with 'wpa_cli reconfigure' command.
578 Configuration file can include one or more network blocks, e.g., one
579 for each used SSID. wpa_supplicant will automatically select the best
580 betwork based on the order of network blocks in the configuration
581 file, network security level (WPA/WPA2 is preferred), and signal
584 Example configuration files for some common configurations:
586 1) WPA-Personal (PSK) as home network and WPA-Enterprise with EAP-TLS as work
589 # allow frontend (e.g., wpa_cli) to be used by all users in 'wheel' group
590 ctrl_interface=/var/run/wpa_supplicant
591 ctrl_interface_group=wheel
593 # home network; allow all valid ciphers
598 psk="very secret passphrase"
601 # work network; use EAP-TLS with WPA; allow only CCMP and TKIP ciphers
609 identity="user@example.com"
610 ca_cert="/etc/cert/ca.pem"
611 client_cert="/etc/cert/user.pem"
612 private_key="/etc/cert/user.prv"
613 private_key_passwd="password"
617 2) WPA-RADIUS/EAP-PEAP/MSCHAPv2 with RADIUS servers that use old peaplabel
618 (e.g., Funk Odyssey and SBR, Meetinghouse Aegis, Interlink RAD-Series)
620 ctrl_interface=/var/run/wpa_supplicant
621 ctrl_interface_group=wheel
627 identity="user@example.com"
629 ca_cert="/etc/cert/ca.pem"
631 phase2="auth=MSCHAPV2"
635 3) EAP-TTLS/EAP-MD5-Challenge configuration with anonymous identity for the
636 unencrypted use. Real identity is sent only within an encrypted TLS tunnel.
638 ctrl_interface=/var/run/wpa_supplicant
639 ctrl_interface_group=wheel
645 identity="user@example.com"
646 anonymous_identity="anonymous@example.com"
648 ca_cert="/etc/cert/ca.pem"
653 4) IEEE 802.1X (i.e., no WPA) with dynamic WEP keys (require both unicast and
654 broadcast); use EAP-TLS for authentication
656 ctrl_interface=/var/run/wpa_supplicant
657 ctrl_interface_group=wheel
663 identity="user@example.com"
664 ca_cert="/etc/cert/ca.pem"
665 client_cert="/etc/cert/user.pem"
666 private_key="/etc/cert/user.prv"
667 private_key_passwd="password"
672 5) Catch all example that allows more or less all configuration modes. The
673 configuration options are used based on what security policy is used in the
674 selected SSID. This is mostly for testing and is not recommended for normal
677 ctrl_interface=/var/run/wpa_supplicant
678 ctrl_interface_group=wheel
682 key_mgmt=WPA-EAP WPA-PSK IEEE8021X NONE
684 group=CCMP TKIP WEP104 WEP40
685 psk="very secret passphrase"
687 identity="user@example.com"
689 ca_cert="/etc/cert/ca.pem"
690 client_cert="/etc/cert/user.pem"
691 private_key="/etc/cert/user.prv"
692 private_key_passwd="password"
694 ca_cert2="/etc/cert/ca2.pem"
695 client_cert2="/etc/cer/user.pem"
696 private_key2="/etc/cer/user.prv"
697 private_key2_passwd="password"
701 6) Authentication for wired Ethernet. This can be used with 'wired' or
702 'roboswitch' interface (-Dwired or -Droboswitch on command line).
704 ctrl_interface=/var/run/wpa_supplicant
705 ctrl_interface_group=wheel
720 Some EAP authentication methods require use of certificates. EAP-TLS
721 uses both server side and client certificates whereas EAP-PEAP and
722 EAP-TTLS only require the server side certificate. When client
723 certificate is used, a matching private key file has to also be
724 included in configuration. If the private key uses a passphrase, this
725 has to be configured in wpa_supplicant.conf ("private_key_passwd").
727 wpa_supplicant supports X.509 certificates in PEM and DER
728 formats. User certificate and private key can be included in the same
731 If the user certificate and private key is received in PKCS#12/PFX
732 format, they need to be converted to suitable PEM/DER format for
733 wpa_supplicant. This can be done, e.g., with following commands:
735 # convert client certificate and private key to PEM format
736 openssl pkcs12 -in example.pfx -out user.pem -clcerts
737 # convert CA certificate (if included in PFX file) to PEM format
738 openssl pkcs12 -in example.pfx -out ca.pem -cacerts -nokeys
745 wpa_cli is a text-based frontend program for interacting with
746 wpa_supplicant. It is used to query current status, change
747 configuration, trigger events, and request interactive user input.
749 wpa_cli can show the current authentication status, selected security
750 mode, dot11 and dot1x MIBs, etc. In addition, it can configure some
751 variables like EAPOL state machine parameters and trigger events like
752 reassociation and IEEE 802.1X logoff/logon. wpa_cli provides a user
753 interface to request authentication information, like username and
754 password, if these are not included in the configuration. This can be
755 used to implement, e.g., one-time-passwords or generic token card
756 authentication where the authentication is based on a
757 challenge-response that uses an external device for generating the
760 The control interface of wpa_supplicant can be configured to allow
761 non-root user access (ctrl_interface_group in the configuration
762 file). This makes it possible to run wpa_cli with a normal user
765 wpa_cli supports two modes: interactive and command line. Both modes
766 share the same command set and the main difference is in interactive
767 mode providing access to unsolicited messages (event messages,
768 username/password requests).
770 Interactive mode is started when wpa_cli is executed without including
771 the command as a command line parameter. Commands are then entered on
772 the wpa_cli prompt. In command line mode, the same commands are
773 entered as command line arguments for wpa_cli.
776 Interactive authentication parameters request
778 When wpa_supplicant need authentication parameters, like username and
779 password, which are not present in the configuration file, it sends a
780 request message to all attached frontend programs, e.g., wpa_cli in
781 interactive mode. wpa_cli shows these requests with
782 "CTRL-REQ-<type>-<id>:<text>" prefix. <type> is IDENTITY, PASSWORD, or
783 OTP (one-time-password). <id> is a unique identifier for the current
784 network. <text> is description of the request. In case of OTP request,
785 it includes the challenge from the authentication server.
787 The reply to these requests can be given with 'identity', 'password',
788 and 'otp' commands. <id> needs to be copied from the the matching
789 request. 'password' and 'otp' commands can be used regardless of
790 whether the request was for PASSWORD or OTP. The main difference
791 between these two commands is that values given with 'password' are
792 remembered as long as wpa_supplicant is running whereas values given
793 with 'otp' are used only once and then forgotten, i.e., wpa_supplicant
794 will ask frontend for a new value for every use. This can be used to
795 implement one-time-password lists and generic token card -based
798 Example request for password and a matching reply:
800 CTRL-REQ-PASSWORD-1:Password needed for SSID foobar
801 > password 1 mysecretpassword
803 Example request for generic token card challenge-response:
805 CTRL-REQ-OTP-2:Challenge 1235663 needed for SSID foobar
811 status = get current WPA/EAPOL/EAP status
812 mib = get MIB variables (dot1x, dot11)
813 help = show this usage help
814 interface [ifname] = show interfaces/select interface
815 level <debug level> = change debug level
816 license = show full wpa_cli license
817 logoff = IEEE 802.1X EAPOL state machine logoff
818 logon = IEEE 802.1X EAPOL state machine logon
819 set = set variables (shows list of variables when run without arguments)
820 pmksa = show PMKSA cache
821 reassociate = force reassociation
822 reconfigure = force wpa_supplicant to re-read its configuration file
823 preauthenticate <BSSID> = force preauthentication
824 identity <network id> <identity> = configure identity for an SSID
825 password <network id> <password> = configure password for an SSID
826 pin <network id> <pin> = configure pin for an SSID
827 otp <network id> <password> = configure one-time-password for an SSID
828 passphrase <network id> <passphrase> = configure private key passphrase
830 bssid <network id> <BSSID> = set preferred BSSID for an SSID
831 list_networks = list configured networks
832 select_network <network id> = select a network (disable others)
833 enable_network <network id> = enable a network
834 disable_network <network id> = disable a network
835 add_network = add a network
836 remove_network <network id> = remove a network
837 set_network <network id> <variable> <value> = set network variables (shows
838 list of variables when run without arguments)
839 get_network <network id> <variable> = get network variables
840 save_config = save the current configuration
841 disconnect = disconnect and wait for reassociate command before connecting
842 scan = request new BSS scan
843 scan_results = get latest scan results
844 get_capability <eap/pairwise/group/key_mgmt/proto/auth_alg> = get capabilies
845 terminate = terminate wpa_supplicant
849 wpa_cli command line options
851 wpa_cli [-p<path to ctrl sockets>] [-i<ifname>] [-hvB] [-a<action file>] \
852 [-P<pid file>] [-g<global ctrl>] [command..]
853 -h = help (show this usage text)
854 -v = shown version information
855 -a = run in daemon mode executing the action file based on events from
857 -B = run a daemon in the background
858 default path: /var/run/wpa_supplicant
859 default interface: first interface found in socket path
862 Using wpa_cli to run external program on connect/disconnect
863 -----------------------------------------------------------
865 wpa_cli can used to run external programs whenever wpa_supplicant
866 connects or disconnects from a network. This can be used, e.g., to
867 update network configuration and/or trigget DHCP client to update IP
870 One wpa_cli process in "action" mode needs to be started for each
871 interface. For example, the following command starts wpa_cli for the
872 default ingterface (-i can be used to select the interface in case of
873 more than one interface being used at the same time):
875 wpa_cli -a/sbin/wpa_action.sh -B
877 The action file (-a option, /sbin/wpa_action.sh in this example) will
878 be executed whenever wpa_supplicant completes authentication (connect
879 event) or detects disconnection). The action script will be called
880 with two command line arguments: interface name and event (CONNECTED
881 or DISCONNECTED). If the action script needs to get more information
882 about the current network, it can use 'wpa_cli status' to query
883 wpa_supplicant for more information.
885 Following example can be used as a simple template for an action
893 if [ "$CMD" == "CONNECTED" ]; then
894 SSID=`wpa_cli -i$IFNAME status | grep ^ssid= | cut -f2- -d=`
895 # configure network, signal DHCP client, etc.
898 if [ "$CMD" == "DISCONNECTED" ]; then
899 # remove network configuration, if needed
904 Integrating with pcmcia-cs/cardmgr scripts
905 ------------------------------------------
907 wpa_supplicant needs to be running when using a wireless network with
908 WPA. It can be started either from system startup scripts or from
909 pcmcia-cs/cardmgr scripts (when using PC Cards). WPA handshake must be
910 completed before data frames can be exchanged, so wpa_supplicant
911 should be started before DHCP client.
913 For example, following small changes to pcmcia-cs scripts can be used
914 to enable WPA support:
916 Add MODE="Managed" and WPA="y" to the network scheme in
917 /etc/pcmcia/wireless.opts.
919 Add the following block to the end of 'start' action handler in
920 /etc/pcmcia/wireless:
922 if [ "$WPA" = "y" -a -x /usr/local/bin/wpa_supplicant ]; then
923 /usr/local/bin/wpa_supplicant -B -c/etc/wpa_supplicant.conf \
927 Add the following block to the end of 'stop' action handler (may need
928 to be separated from other actions) in /etc/pcmcia/wireless:
930 if [ "$WPA" = "y" -a -x /usr/local/bin/wpa_supplicant ]; then
931 killall wpa_supplicant
934 This will make cardmgr start wpa_supplicant when the card is plugged
939 Dynamic interface add and operation without configuration files
940 ---------------------------------------------------------------
942 wpa_supplicant can be started without any configuration files or
943 network interfaces. When used in this way, a global (i.e., per
944 wpa_supplicant process) control interface is used to add and remove
945 network interfaces. Each network interface can then be configured
946 through a per-network interface control interface. For example,
947 following commands show how to start wpa_supplicant without any
948 network interfaces and then add a network interface and configure a
951 # Start wpa_supplicant in the background
952 wpa_supplicant -g/var/run/wpa_supplicant-global -B
954 # Add a new interface (wlan0, no configuration file, driver=wext, and
955 # enable control interface)
956 wpa_cli -g/var/run/wpa_supplicant-global interface_add wlan0 \
957 "" wext /var/run/wpa_supplicant
959 # Configure a network using the newly added network interface:
960 wpa_cli -iwlan0 add_network
961 wpa_cli -iwlan0 set_network 0 ssid '"test"'
962 wpa_cli -iwlan0 set_network 0 key_mgmt WPA-PSK
963 wpa_cli -iwlan0 set_network 0 psk '"12345678"'
964 wpa_cli -iwlan0 set_network 0 pairwise TKIP
965 wpa_cli -iwlan0 set_network 0 group TKIP
966 wpa_cli -iwlan0 set_network 0 proto WPA
967 wpa_cli -iwlan0 enable_network 0
969 # At this point, the new network interface should start trying to associate
970 # with the WPA-PSK network using SSID test.
972 # Remove network interface
973 wpa_cli -g/var/run/wpa_supplicant-global interface_remove wlan0
979 To minimize the size of code that needs to be run with root privileges
980 (e.g., to control wireless interface operation), wpa_supplicant
981 supports optional privilege separation. If enabled, this separates the
982 privileged operations into a separate process (wpa_priv) while leaving
983 rest of the code (e.g., EAP authentication and WPA handshakes) into an
984 unprivileged process (wpa_supplicant) that can be run as non-root
985 user. Privilege separation restricts the effects of potential software
986 errors by containing the majority of the code in an unprivileged
987 process to avoid full system compromise.
989 Privilege separation is not enabled by default and it can be enabled
990 by adding CONFIG_PRIVSEP=y to the build configuration (.config). When
991 enabled, the privileged operations (driver wrapper and l2_packet) are
992 linked into a separate daemon program, wpa_priv. The unprivileged
993 program, wpa_supplicant, will be built with a special driver/l2_packet
994 wrappers that communicate with the privileged wpa_priv process to
995 perform the needed operations. wpa_priv can control what privileged
998 wpa_priv needs to be run with network admin privileges (usually, root
999 user). It opens a UNIX domain socket for each interface that is
1000 included on the command line; any other interface will be off limits
1001 for wpa_supplicant in this kind of configuration. After this,
1002 wpa_supplicant can be run as a non-root user (e.g., all standard users
1003 on a laptop or as a special non-privileged user account created just
1004 for this purpose to limit access to user files even further).
1007 Example configuration:
1008 - create user group for users that are allowed to use wpa_supplicant
1009 ('wpapriv' in this example) and assign users that should be able to
1010 use wpa_supplicant into that group
1011 - create /var/run/wpa_priv directory for UNIX domain sockets and control
1012 user access by setting it accessible only for the wpapriv group:
1013 mkdir /var/run/wpa_priv
1014 chown root:wpapriv /var/run/wpa_priv
1015 chmod 0750 /var/run/wpa_priv
1016 - start wpa_priv as root (e.g., from system startup scripts) with the
1017 enabled interfaces configured on the command line:
1018 wpa_priv -B -P /var/run/wpa_priv.pid wext:ath0
1019 - run wpa_supplicant as non-root with a user that is in wpapriv group:
1020 wpa_supplicant -i ath0 -c wpa_supplicant.conf
1022 wpa_priv does not use the network interface before wpa_supplicant is
1023 started, so it is fine to include network interfaces that are not
1024 available at the time wpa_priv is started. As an alternative, wpa_priv
1025 can be started when an interface is added (hotplug/udev/etc. scripts).
1026 wpa_priv can control multiple interface with one process, but it is
1027 also possible to run multiple wpa_priv processes at the same time, if