4 Copyright (c) 2003-2014, Jouni Malinen <j@w1.fi> and contributors
7 This program is licensed under the BSD license (the one with
8 advertisement clause removed).
10 If you are submitting changes to the project, please see CONTRIBUTIONS
11 file for more instructions.
18 This software may be distributed, used, and modified under the terms of
21 Redistribution and use in source and binary forms, with or without
22 modification, are permitted provided that the following conditions are
25 1. Redistributions of source code must retain the above copyright
26 notice, this list of conditions and the following disclaimer.
28 2. Redistributions in binary form must reproduce the above copyright
29 notice, this list of conditions and the following disclaimer in the
30 documentation and/or other materials provided with the distribution.
32 3. Neither the name(s) of the above-listed copyright holder(s) nor the
33 names of its contributors may be used to endorse or promote products
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36 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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38 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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46 OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
53 Supported WPA/IEEE 802.11i features:
54 - WPA-PSK ("WPA-Personal")
55 - WPA with EAP (e.g., with RADIUS authentication server) ("WPA-Enterprise")
56 Following authentication methods are supported with an integrate IEEE 802.1X
59 * EAP-PEAP/MSCHAPv2 (both PEAPv0 and PEAPv1)
60 * EAP-PEAP/TLS (both PEAPv0 and PEAPv1)
61 * EAP-PEAP/GTC (both PEAPv0 and PEAPv1)
62 * EAP-PEAP/OTP (both PEAPv0 and PEAPv1)
63 * EAP-PEAP/MD5-Challenge (both PEAPv0 and PEAPv1)
64 * EAP-TTLS/EAP-MD5-Challenge
67 * EAP-TTLS/EAP-MSCHAPv2
80 * LEAP (note: requires special support from the driver for IEEE 802.11
82 (following methods are supported, but since they do not generate keying
83 material, they cannot be used with WPA or IEEE 802.1X WEP keying)
88 - key management for CCMP, TKIP, WEP104, WEP40
89 - RSN/WPA2 (IEEE 802.11i)
93 Supported TLS/crypto libraries:
97 Internal TLS/crypto implementation (optional):
98 - can be used in place of an external TLS/crypto library
100 - X.509 certificate processing
105 - minimal size (ca. 50 kB binary, parts of which are already needed for WPA;
106 TLSv1/X.509/ASN.1/RSA/bignum parts are about 25 kB on x86)
112 Current hardware/software requirements:
113 - Linux kernel 2.4.x or 2.6.x with Linux Wireless Extensions v15 or newer
116 - Microsoft Windows with WinPcap (at least WinXP, may work with other versions)
118 Linux drivers that support cfg80211/nl80211. Even though there are
119 number of driver specific interface included in wpa_supplicant, please
120 note that Linux drivers are moving to use generic wireless configuration
121 interface driver_nl80211 (-Dnl80211 on wpa_supplicant command line)
122 should be the default option to start with before falling back to driver
125 Linux drivers that support WPA/WPA2 configuration with the generic
126 Linux wireless extensions (WE-18 or newer). Obsoleted by nl80211.
128 In theory, any driver that supports Linux wireless extensions can be
129 used with IEEE 802.1X (i.e., not WPA) when using ap_scan=0 option in
132 Wired Ethernet drivers (with ap_scan=0)
134 BSD net80211 layer (e.g., Atheros driver)
135 At the moment, this is for FreeBSD 6-CURRENT branch and NetBSD-current.
138 The current Windows port requires WinPcap (http://winpcap.polito.it/).
139 See README-Windows.txt for more information.
141 wpa_supplicant was designed to be portable for different drivers and
142 operating systems. Hopefully, support for more wlan cards and OSes will be
143 added in the future. See developer's documentation
144 (http://hostap.epitest.fi/wpa_supplicant/devel/) for more information about the
145 design of wpa_supplicant and porting to other drivers. One main goal
146 is to add full WPA/WPA2 support to Linux wireless extensions to allow
147 new drivers to be supported without having to implement new
148 driver-specific interface code in wpa_supplicant.
150 Optional libraries for layer2 packet processing:
151 - libpcap (tested with 0.7.2, most relatively recent versions assumed to work,
152 this is likely to be available with most distributions,
154 - libdnet (tested with v1.4, most versions assumed to work,
155 http://libdnet.sourceforge.net/)
157 These libraries are _not_ used in the default Linux build. Instead,
158 internal Linux specific implementation is used. libpcap/libdnet are
159 more portable and they can be used by adding CONFIG_L2_PACKET=pcap into
160 .config. They may also be selected automatically for other operating
161 systems. In case of Windows builds, WinPcap is used by default
162 (CONFIG_L2_PACKET=winpcap).
165 Optional libraries for EAP-TLS, EAP-PEAP, and EAP-TTLS:
166 - OpenSSL (tested with 0.9.7c and 0.9.7d, and 0.9.8 versions; assumed to
167 work with most relatively recent versions; this is likely to be
168 available with most distributions, http://www.openssl.org/)
170 - internal TLSv1 implementation
172 TLS options for EAP-FAST:
173 - OpenSSL 0.9.8d _with_ openssl-0.9.8d-tls-extensions.patch applied
174 (i.e., the default OpenSSL package does not include support for
175 extensions needed for EAP-FAST)
176 - internal TLSv1 implementation
178 One of these libraries is needed when EAP-TLS, EAP-PEAP, EAP-TTLS, or
179 EAP-FAST support is enabled. WPA-PSK mode does not require this or EAPOL/EAP
180 implementation. A configuration file, .config, for compilation is
181 needed to enable IEEE 802.1X/EAPOL and EAP methods. Note that EAP-MD5,
182 EAP-GTC, EAP-OTP, and EAP-MSCHAPV2 cannot be used alone with WPA, so
183 they should only be enabled if testing the EAPOL/EAP state
184 machines. However, there can be used as inner authentication
185 algorithms with EAP-PEAP and EAP-TTLS.
187 See Building and installing section below for more detailed
188 information about the wpa_supplicant build time configuration.
195 The original security mechanism of IEEE 802.11 standard was not
196 designed to be strong and has proven to be insufficient for most
197 networks that require some kind of security. Task group I (Security)
198 of IEEE 802.11 working group (http://www.ieee802.org/11/) has worked
199 to address the flaws of the base standard and has in practice
200 completed its work in May 2004. The IEEE 802.11i amendment to the IEEE
201 802.11 standard was approved in June 2004 and published in July 2004.
203 Wi-Fi Alliance (http://www.wi-fi.org/) used a draft version of the
204 IEEE 802.11i work (draft 3.0) to define a subset of the security
205 enhancements that can be implemented with existing wlan hardware. This
206 is called Wi-Fi Protected Access<TM> (WPA). This has now become a
207 mandatory component of interoperability testing and certification done
208 by Wi-Fi Alliance. Wi-Fi provides information about WPA at its web
209 site (http://www.wi-fi.org/OpenSection/protected_access.asp).
211 IEEE 802.11 standard defined wired equivalent privacy (WEP) algorithm
212 for protecting wireless networks. WEP uses RC4 with 40-bit keys,
213 24-bit initialization vector (IV), and CRC32 to protect against packet
214 forgery. All these choices have proven to be insufficient: key space is
215 too small against current attacks, RC4 key scheduling is insufficient
216 (beginning of the pseudorandom stream should be skipped), IV space is
217 too small and IV reuse makes attacks easier, there is no replay
218 protection, and non-keyed authentication does not protect against bit
219 flipping packet data.
221 WPA is an intermediate solution for the security issues. It uses
222 Temporal Key Integrity Protocol (TKIP) to replace WEP. TKIP is a
223 compromise on strong security and possibility to use existing
224 hardware. It still uses RC4 for the encryption like WEP, but with
225 per-packet RC4 keys. In addition, it implements replay protection,
226 keyed packet authentication mechanism (Michael MIC).
228 Keys can be managed using two different mechanisms. WPA can either use
229 an external authentication server (e.g., RADIUS) and EAP just like
230 IEEE 802.1X is using or pre-shared keys without need for additional
231 servers. Wi-Fi calls these "WPA-Enterprise" and "WPA-Personal",
232 respectively. Both mechanisms will generate a master session key for
233 the Authenticator (AP) and Supplicant (client station).
235 WPA implements a new key handshake (4-Way Handshake and Group Key
236 Handshake) for generating and exchanging data encryption keys between
237 the Authenticator and Supplicant. This handshake is also used to
238 verify that both Authenticator and Supplicant know the master session
239 key. These handshakes are identical regardless of the selected key
240 management mechanism (only the method for generating master session
248 The design for parts of IEEE 802.11i that were not included in WPA has
249 finished (May 2004) and this amendment to IEEE 802.11 was approved in
250 June 2004. Wi-Fi Alliance is using the final IEEE 802.11i as a new
251 version of WPA called WPA2. This includes, e.g., support for more
252 robust encryption algorithm (CCMP: AES in Counter mode with CBC-MAC)
253 to replace TKIP and optimizations for handoff (reduced number of
254 messages in initial key handshake, pre-authentication, and PMKSA caching).
261 wpa_supplicant is an implementation of the WPA Supplicant component,
262 i.e., the part that runs in the client stations. It implements WPA key
263 negotiation with a WPA Authenticator and EAP authentication with
264 Authentication Server. In addition, it controls the roaming and IEEE
265 802.11 authentication/association of the wlan driver.
267 wpa_supplicant is designed to be a "daemon" program that runs in the
268 background and acts as the backend component controlling the wireless
269 connection. wpa_supplicant supports separate frontend programs and an
270 example text-based frontend, wpa_cli, is included with wpa_supplicant.
272 Following steps are used when associating with an AP using WPA:
274 - wpa_supplicant requests the kernel driver to scan neighboring BSSes
275 - wpa_supplicant selects a BSS based on its configuration
276 - wpa_supplicant requests the kernel driver to associate with the chosen
278 - If WPA-EAP: integrated IEEE 802.1X Supplicant completes EAP
279 authentication with the authentication server (proxied by the
280 Authenticator in the AP)
281 - If WPA-EAP: master key is received from the IEEE 802.1X Supplicant
282 - If WPA-PSK: wpa_supplicant uses PSK as the master session key
283 - wpa_supplicant completes WPA 4-Way Handshake and Group Key Handshake
284 with the Authenticator (AP)
285 - wpa_supplicant configures encryption keys for unicast and broadcast
286 - normal data packets can be transmitted and received
290 Building and installing
291 -----------------------
293 In order to be able to build wpa_supplicant, you will first need to
294 select which parts of it will be included. This is done by creating a
295 build time configuration file, .config, in the wpa_supplicant root
296 directory. Configuration options are text lines using following
297 format: CONFIG_<option>=y. Lines starting with # are considered
298 comments and are ignored. See defconfig file for an example configuration
299 and a list of available options and additional notes.
301 The build time configuration can be used to select only the needed
302 features and limit the binary size and requirements for external
303 libraries. The main configuration parts are the selection of which
304 driver interfaces (e.g., nl80211, wext, ..) and which authentication
305 methods (e.g., EAP-TLS, EAP-PEAP, ..) are included.
307 Following build time configuration options are used to control IEEE
308 802.1X/EAPOL and EAP state machines and all EAP methods. Including
309 TLS, PEAP, or TTLS will require linking wpa_supplicant with OpenSSL
310 library for TLS implementation. Alternatively, GnuTLS or the internal
311 TLSv1 implementation can be used for TLS functionaly.
313 CONFIG_IEEE8021X_EAPOL=y
315 CONFIG_EAP_MSCHAPV2=y
330 Following option can be used to include GSM SIM/USIM interface for GSM/UMTS
331 authentication algorithm (for EAP-SIM/EAP-AKA). This requires pcsc-lite
332 (http://www.linuxnet.com/) for smart card access.
336 Following options can be added to .config to select which driver
337 interfaces are included.
339 CONFIG_DRIVER_NL80211=y
344 Following example includes some more features and driver interfaces that
345 are included in the wpa_supplicant package:
347 CONFIG_DRIVER_NL80211=y
351 CONFIG_IEEE8021X_EAPOL=y
353 CONFIG_EAP_MSCHAPV2=y
369 EAP-PEAP and EAP-TTLS will automatically include configured EAP
370 methods (MD5, OTP, GTC, MSCHAPV2) for inner authentication selection.
373 After you have created a configuration file, you can build
374 wpa_supplicant and wpa_cli with 'make' command. You may then install
375 the binaries to a suitable system directory, e.g., /usr/local/bin.
379 # build wpa_supplicant and wpa_cli
381 # install binaries (this may need root privileges)
382 cp wpa_cli wpa_supplicant /usr/local/bin
385 You will need to make a configuration file, e.g.,
386 /etc/wpa_supplicant.conf, with network configuration for the networks
387 you are going to use. Configuration file section below includes
388 explanation fo the configuration file format and includes various
389 examples. Once the configuration is ready, you can test whether the
390 configuration work by first running wpa_supplicant with following
391 command to start it on foreground with debugging enabled:
393 wpa_supplicant -iwlan0 -c/etc/wpa_supplicant.conf -d
395 Assuming everything goes fine, you can start using following command
396 to start wpa_supplicant on background without debugging:
398 wpa_supplicant -iwlan0 -c/etc/wpa_supplicant.conf -B
400 Please note that if you included more than one driver interface in the
401 build time configuration (.config), you may need to specify which
402 interface to use by including -D<driver name> option on the command
403 line. See following section for more details on command line options
412 wpa_supplicant [-BddfhKLqqtuvwW] [-P<pid file>] [-g<global ctrl>] \
414 -i<ifname> -c<config file> [-C<ctrl>] [-D<driver>] [-p<driver_param>] \
415 [-b<br_ifname> [-N -i<ifname> -c<conf> [-C<ctrl>] [-D<driver>] \
416 [-p<driver_param>] [-b<br_ifname>] [-m<P2P Device config file>] ...
419 -b = optional bridge interface name
420 -B = run daemon in the background
421 -c = Configuration file
422 -C = ctrl_interface parameter (only used if -c is not)
424 -d = increase debugging verbosity (-dd even more)
425 -D = driver name (can be multiple drivers: nl80211,wext)
426 -f = Log output to default log location (normally /tmp)
427 -g = global ctrl_interface
428 -G = global ctrl_interface group
429 -K = include keys (passwords, etc.) in debug output
430 -t = include timestamp in debug messages
431 -h = show this help text
432 -L = show license (BSD)
433 -p = driver parameters
435 -q = decrease debugging verbosity (-qq even less)
436 -u = enable DBus control interface
438 -w = wait for interface to be added, if needed
439 -W = wait for a control interface monitor before starting
440 -N = start describing new interface
441 -m = Configuration file for the P2P Device
444 nl80211 = Linux nl80211/cfg80211
445 wext = Linux wireless extensions (generic)
446 wired = wpa_supplicant wired Ethernet driver
447 roboswitch = wpa_supplicant Broadcom switch driver
448 bsd = BSD 802.11 support (Atheros, etc.)
449 ndis = Windows NDIS driver
451 In most common cases, wpa_supplicant is started with
453 wpa_supplicant -B -c/etc/wpa_supplicant.conf -iwlan0
455 This makes the process fork into background.
457 The easiest way to debug problems, and to get debug log for bug
458 reports, is to start wpa_supplicant on foreground with debugging
461 wpa_supplicant -c/etc/wpa_supplicant.conf -iwlan0 -d
463 If the specific driver wrapper is not known beforehand, it is possible
464 to specify multiple comma separated driver wrappers on the command
465 line. wpa_supplicant will use the first driver wrapper that is able to
466 initialize the interface.
468 wpa_supplicant -Dnl80211,wext -c/etc/wpa_supplicant.conf -iwlan0
471 wpa_supplicant can control multiple interfaces (radios) either by
472 running one process for each interface separately or by running just
473 one process and list of options at command line. Each interface is
474 separated with -N argument. As an example, following command would
475 start wpa_supplicant for two interfaces:
478 -c wpa1.conf -i wlan0 -D nl80211 -N \
479 -c wpa2.conf -i wlan1 -D wext
482 If the interface is added in a Linux bridge (e.g., br0), the bridge
483 interface needs to be configured to wpa_supplicant in addition to the
486 wpa_supplicant -cw.conf -Dnl80211 -iwlan0 -bbr0
492 wpa_supplicant is configured using a text file that lists all accepted
493 networks and security policies, including pre-shared keys. See
494 example configuration file, wpa_supplicant.conf, for detailed
495 information about the configuration format and supported fields.
497 Changes to configuration file can be reloaded be sending SIGHUP signal
498 to wpa_supplicant ('killall -HUP wpa_supplicant'). Similarly,
499 reloading can be triggered with 'wpa_cli reconfigure' command.
501 Configuration file can include one or more network blocks, e.g., one
502 for each used SSID. wpa_supplicant will automatically select the best
503 betwork based on the order of network blocks in the configuration
504 file, network security level (WPA/WPA2 is preferred), and signal
507 Example configuration files for some common configurations:
509 1) WPA-Personal (PSK) as home network and WPA-Enterprise with EAP-TLS as work
512 # allow frontend (e.g., wpa_cli) to be used by all users in 'wheel' group
513 ctrl_interface=/var/run/wpa_supplicant
514 ctrl_interface_group=wheel
516 # home network; allow all valid ciphers
521 psk="very secret passphrase"
524 # work network; use EAP-TLS with WPA; allow only CCMP and TKIP ciphers
532 identity="user@example.com"
533 ca_cert="/etc/cert/ca.pem"
534 client_cert="/etc/cert/user.pem"
535 private_key="/etc/cert/user.prv"
536 private_key_passwd="password"
540 2) WPA-RADIUS/EAP-PEAP/MSCHAPv2 with RADIUS servers that use old peaplabel
541 (e.g., Funk Odyssey and SBR, Meetinghouse Aegis, Interlink RAD-Series)
543 ctrl_interface=/var/run/wpa_supplicant
544 ctrl_interface_group=wheel
550 identity="user@example.com"
552 ca_cert="/etc/cert/ca.pem"
554 phase2="auth=MSCHAPV2"
558 3) EAP-TTLS/EAP-MD5-Challenge configuration with anonymous identity for the
559 unencrypted use. Real identity is sent only within an encrypted TLS tunnel.
561 ctrl_interface=/var/run/wpa_supplicant
562 ctrl_interface_group=wheel
568 identity="user@example.com"
569 anonymous_identity="anonymous@example.com"
571 ca_cert="/etc/cert/ca.pem"
576 4) IEEE 802.1X (i.e., no WPA) with dynamic WEP keys (require both unicast and
577 broadcast); use EAP-TLS for authentication
579 ctrl_interface=/var/run/wpa_supplicant
580 ctrl_interface_group=wheel
586 identity="user@example.com"
587 ca_cert="/etc/cert/ca.pem"
588 client_cert="/etc/cert/user.pem"
589 private_key="/etc/cert/user.prv"
590 private_key_passwd="password"
595 5) Catch all example that allows more or less all configuration modes. The
596 configuration options are used based on what security policy is used in the
597 selected SSID. This is mostly for testing and is not recommended for normal
600 ctrl_interface=/var/run/wpa_supplicant
601 ctrl_interface_group=wheel
605 key_mgmt=WPA-EAP WPA-PSK IEEE8021X NONE
607 group=CCMP TKIP WEP104 WEP40
608 psk="very secret passphrase"
610 identity="user@example.com"
612 ca_cert="/etc/cert/ca.pem"
613 client_cert="/etc/cert/user.pem"
614 private_key="/etc/cert/user.prv"
615 private_key_passwd="password"
617 ca_cert2="/etc/cert/ca2.pem"
618 client_cert2="/etc/cer/user.pem"
619 private_key2="/etc/cer/user.prv"
620 private_key2_passwd="password"
624 6) Authentication for wired Ethernet. This can be used with 'wired' or
625 'roboswitch' interface (-Dwired or -Droboswitch on command line).
627 ctrl_interface=/var/run/wpa_supplicant
628 ctrl_interface_group=wheel
643 Some EAP authentication methods require use of certificates. EAP-TLS
644 uses both server side and client certificates whereas EAP-PEAP and
645 EAP-TTLS only require the server side certificate. When client
646 certificate is used, a matching private key file has to also be
647 included in configuration. If the private key uses a passphrase, this
648 has to be configured in wpa_supplicant.conf ("private_key_passwd").
650 wpa_supplicant supports X.509 certificates in PEM and DER
651 formats. User certificate and private key can be included in the same
654 If the user certificate and private key is received in PKCS#12/PFX
655 format, they need to be converted to suitable PEM/DER format for
656 wpa_supplicant. This can be done, e.g., with following commands:
658 # convert client certificate and private key to PEM format
659 openssl pkcs12 -in example.pfx -out user.pem -clcerts
660 # convert CA certificate (if included in PFX file) to PEM format
661 openssl pkcs12 -in example.pfx -out ca.pem -cacerts -nokeys
668 wpa_cli is a text-based frontend program for interacting with
669 wpa_supplicant. It is used to query current status, change
670 configuration, trigger events, and request interactive user input.
672 wpa_cli can show the current authentication status, selected security
673 mode, dot11 and dot1x MIBs, etc. In addition, it can configure some
674 variables like EAPOL state machine parameters and trigger events like
675 reassociation and IEEE 802.1X logoff/logon. wpa_cli provides a user
676 interface to request authentication information, like username and
677 password, if these are not included in the configuration. This can be
678 used to implement, e.g., one-time-passwords or generic token card
679 authentication where the authentication is based on a
680 challenge-response that uses an external device for generating the
683 The control interface of wpa_supplicant can be configured to allow
684 non-root user access (ctrl_interface_group in the configuration
685 file). This makes it possible to run wpa_cli with a normal user
688 wpa_cli supports two modes: interactive and command line. Both modes
689 share the same command set and the main difference is in interactive
690 mode providing access to unsolicited messages (event messages,
691 username/password requests).
693 Interactive mode is started when wpa_cli is executed without including
694 the command as a command line parameter. Commands are then entered on
695 the wpa_cli prompt. In command line mode, the same commands are
696 entered as command line arguments for wpa_cli.
699 Interactive authentication parameters request
701 When wpa_supplicant need authentication parameters, like username and
702 password, which are not present in the configuration file, it sends a
703 request message to all attached frontend programs, e.g., wpa_cli in
704 interactive mode. wpa_cli shows these requests with
705 "CTRL-REQ-<type>-<id>:<text>" prefix. <type> is IDENTITY, PASSWORD, or
706 OTP (one-time-password). <id> is a unique identifier for the current
707 network. <text> is description of the request. In case of OTP request,
708 it includes the challenge from the authentication server.
710 The reply to these requests can be given with 'identity', 'password',
711 and 'otp' commands. <id> needs to be copied from the the matching
712 request. 'password' and 'otp' commands can be used regardless of
713 whether the request was for PASSWORD or OTP. The main difference
714 between these two commands is that values given with 'password' are
715 remembered as long as wpa_supplicant is running whereas values given
716 with 'otp' are used only once and then forgotten, i.e., wpa_supplicant
717 will ask frontend for a new value for every use. This can be used to
718 implement one-time-password lists and generic token card -based
721 Example request for password and a matching reply:
723 CTRL-REQ-PASSWORD-1:Password needed for SSID foobar
724 > password 1 mysecretpassword
726 Example request for generic token card challenge-response:
728 CTRL-REQ-OTP-2:Challenge 1235663 needed for SSID foobar
734 status = get current WPA/EAPOL/EAP status
735 mib = get MIB variables (dot1x, dot11)
736 help = show this usage help
737 interface [ifname] = show interfaces/select interface
738 level <debug level> = change debug level
739 license = show full wpa_cli license
740 logoff = IEEE 802.1X EAPOL state machine logoff
741 logon = IEEE 802.1X EAPOL state machine logon
742 set = set variables (shows list of variables when run without arguments)
743 pmksa = show PMKSA cache
744 reassociate = force reassociation
745 reconfigure = force wpa_supplicant to re-read its configuration file
746 preauthenticate <BSSID> = force preauthentication
747 identity <network id> <identity> = configure identity for an SSID
748 password <network id> <password> = configure password for an SSID
749 pin <network id> <pin> = configure pin for an SSID
750 otp <network id> <password> = configure one-time-password for an SSID
751 passphrase <network id> <passphrase> = configure private key passphrase
753 bssid <network id> <BSSID> = set preferred BSSID for an SSID
754 list_networks = list configured networks
755 select_network <network id> = select a network (disable others)
756 enable_network <network id> = enable a network
757 disable_network <network id> = disable a network
758 add_network = add a network
759 remove_network <network id> = remove a network
760 set_network <network id> <variable> <value> = set network variables (shows
761 list of variables when run without arguments)
762 get_network <network id> <variable> = get network variables
763 save_config = save the current configuration
764 disconnect = disconnect and wait for reassociate command before connecting
765 scan = request new BSS scan
766 scan_results = get latest scan results
767 get_capability <eap/pairwise/group/key_mgmt/proto/auth_alg> = get capabilies
768 terminate = terminate wpa_supplicant
772 wpa_cli command line options
774 wpa_cli [-p<path to ctrl sockets>] [-i<ifname>] [-hvB] [-a<action file>] \
775 [-P<pid file>] [-g<global ctrl>] [command..]
776 -h = help (show this usage text)
777 -v = shown version information
778 -a = run in daemon mode executing the action file based on events from
780 -B = run a daemon in the background
781 default path: /var/run/wpa_supplicant
782 default interface: first interface found in socket path
785 Using wpa_cli to run external program on connect/disconnect
786 -----------------------------------------------------------
788 wpa_cli can used to run external programs whenever wpa_supplicant
789 connects or disconnects from a network. This can be used, e.g., to
790 update network configuration and/or trigget DHCP client to update IP
793 One wpa_cli process in "action" mode needs to be started for each
794 interface. For example, the following command starts wpa_cli for the
795 default ingterface (-i can be used to select the interface in case of
796 more than one interface being used at the same time):
798 wpa_cli -a/sbin/wpa_action.sh -B
800 The action file (-a option, /sbin/wpa_action.sh in this example) will
801 be executed whenever wpa_supplicant completes authentication (connect
802 event) or detects disconnection). The action script will be called
803 with two command line arguments: interface name and event (CONNECTED
804 or DISCONNECTED). If the action script needs to get more information
805 about the current network, it can use 'wpa_cli status' to query
806 wpa_supplicant for more information.
808 Following example can be used as a simple template for an action
816 if [ "$CMD" = "CONNECTED" ]; then
817 SSID=`wpa_cli -i$IFNAME status | grep ^ssid= | cut -f2- -d=`
818 # configure network, signal DHCP client, etc.
821 if [ "$CMD" = "DISCONNECTED" ]; then
822 # remove network configuration, if needed
828 Integrating with pcmcia-cs/cardmgr scripts
829 ------------------------------------------
831 wpa_supplicant needs to be running when using a wireless network with
832 WPA. It can be started either from system startup scripts or from
833 pcmcia-cs/cardmgr scripts (when using PC Cards). WPA handshake must be
834 completed before data frames can be exchanged, so wpa_supplicant
835 should be started before DHCP client.
837 For example, following small changes to pcmcia-cs scripts can be used
838 to enable WPA support:
840 Add MODE="Managed" and WPA="y" to the network scheme in
841 /etc/pcmcia/wireless.opts.
843 Add the following block to the end of 'start' action handler in
844 /etc/pcmcia/wireless:
846 if [ "$WPA" = "y" -a -x /usr/local/bin/wpa_supplicant ]; then
847 /usr/local/bin/wpa_supplicant -B -c/etc/wpa_supplicant.conf \
851 Add the following block to the end of 'stop' action handler (may need
852 to be separated from other actions) in /etc/pcmcia/wireless:
854 if [ "$WPA" = "y" -a -x /usr/local/bin/wpa_supplicant ]; then
855 killall wpa_supplicant
858 This will make cardmgr start wpa_supplicant when the card is plugged
863 Dynamic interface add and operation without configuration files
864 ---------------------------------------------------------------
866 wpa_supplicant can be started without any configuration files or
867 network interfaces. When used in this way, a global (i.e., per
868 wpa_supplicant process) control interface is used to add and remove
869 network interfaces. Each network interface can then be configured
870 through a per-network interface control interface. For example,
871 following commands show how to start wpa_supplicant without any
872 network interfaces and then add a network interface and configure a
875 # Start wpa_supplicant in the background
876 wpa_supplicant -g/var/run/wpa_supplicant-global -B
878 # Add a new interface (wlan0, no configuration file, driver=nl80211, and
879 # enable control interface)
880 wpa_cli -g/var/run/wpa_supplicant-global interface_add wlan0 \
881 "" nl80211 /var/run/wpa_supplicant
883 # Configure a network using the newly added network interface:
884 wpa_cli -iwlan0 add_network
885 wpa_cli -iwlan0 set_network 0 ssid '"test"'
886 wpa_cli -iwlan0 set_network 0 key_mgmt WPA-PSK
887 wpa_cli -iwlan0 set_network 0 psk '"12345678"'
888 wpa_cli -iwlan0 set_network 0 pairwise TKIP
889 wpa_cli -iwlan0 set_network 0 group TKIP
890 wpa_cli -iwlan0 set_network 0 proto WPA
891 wpa_cli -iwlan0 enable_network 0
893 # At this point, the new network interface should start trying to associate
894 # with the WPA-PSK network using SSID test.
896 # Remove network interface
897 wpa_cli -g/var/run/wpa_supplicant-global interface_remove wlan0
903 To minimize the size of code that needs to be run with root privileges
904 (e.g., to control wireless interface operation), wpa_supplicant
905 supports optional privilege separation. If enabled, this separates the
906 privileged operations into a separate process (wpa_priv) while leaving
907 rest of the code (e.g., EAP authentication and WPA handshakes) into an
908 unprivileged process (wpa_supplicant) that can be run as non-root
909 user. Privilege separation restricts the effects of potential software
910 errors by containing the majority of the code in an unprivileged
911 process to avoid full system compromise.
913 Privilege separation is not enabled by default and it can be enabled
914 by adding CONFIG_PRIVSEP=y to the build configuration (.config). When
915 enabled, the privileged operations (driver wrapper and l2_packet) are
916 linked into a separate daemon program, wpa_priv. The unprivileged
917 program, wpa_supplicant, will be built with a special driver/l2_packet
918 wrappers that communicate with the privileged wpa_priv process to
919 perform the needed operations. wpa_priv can control what privileged
922 wpa_priv needs to be run with network admin privileges (usually, root
923 user). It opens a UNIX domain socket for each interface that is
924 included on the command line; any other interface will be off limits
925 for wpa_supplicant in this kind of configuration. After this,
926 wpa_supplicant can be run as a non-root user (e.g., all standard users
927 on a laptop or as a special non-privileged user account created just
928 for this purpose to limit access to user files even further).
931 Example configuration:
932 - create user group for users that are allowed to use wpa_supplicant
933 ('wpapriv' in this example) and assign users that should be able to
934 use wpa_supplicant into that group
935 - create /var/run/wpa_priv directory for UNIX domain sockets and control
936 user access by setting it accessible only for the wpapriv group:
937 mkdir /var/run/wpa_priv
938 chown root:wpapriv /var/run/wpa_priv
939 chmod 0750 /var/run/wpa_priv
940 - start wpa_priv as root (e.g., from system startup scripts) with the
941 enabled interfaces configured on the command line:
942 wpa_priv -B -P /var/run/wpa_priv.pid nl80211:wlan0
943 - run wpa_supplicant as non-root with a user that is in wpapriv group:
944 wpa_supplicant -i ath0 -c wpa_supplicant.conf
946 wpa_priv does not use the network interface before wpa_supplicant is
947 started, so it is fine to include network interfaces that are not
948 available at the time wpa_priv is started. As an alternative, wpa_priv
949 can be started when an interface is added (hotplug/udev/etc. scripts).
950 wpa_priv can control multiple interface with one process, but it is
951 also possible to run multiple wpa_priv processes at the same time, if
955 Linux capabilities instead of privileged process
956 ------------------------------------------------
958 wpa_supplicant performs operations that need special permissions, e.g.,
959 to control the network connection. Traditionally this has been achieved
960 by running wpa_supplicant as a privileged process with effective user id
961 0 (root). Linux capabilities can be used to provide restricted set of
962 capabilities to match the functions needed by wpa_supplicant. The
963 minimum set of capabilities needed for the operations is CAP_NET_ADMIN
966 setcap(8) can be used to set file capabilities. For example:
968 sudo setcap cap_net_raw,cap_net_admin+ep wpa_supplicant
970 Please note that this would give anyone being able to run that
971 wpa_supplicant binary access to the additional capabilities. This can
972 further be limited by file owner/group and mode bits. For example:
974 sudo chown wpas wpa_supplicant
975 sudo chmod 0100 wpa_supplicant
977 This combination of setcap, chown, and chmod commands would allow wpas
978 user to execute wpa_supplicant with additional network admin/raw
981 Common way style of creating a control interface socket in
982 /var/run/wpa_supplicant could not be done by this user, but this
983 directory could be created before starting the wpa_supplicant and set to
984 suitable mode to allow wpa_supplicant to create sockets
985 there. Alternatively, other directory or abstract socket namespace could
986 be used for the control interface.
989 External requests for radio control
990 -----------------------------------
992 External programs can request wpa_supplicant to not start offchannel
993 operations during other tasks that may need exclusive control of the
994 radio. The RADIO_WORK control interface command can be used for this.
996 "RADIO_WORK add <name> [freq=<MHz>] [timeout=<seconds>]" command can be
997 used to reserve a slot for radio access. If freq is specified, other
998 radio work items on the same channel may be completed in
999 parallel. Otherwise, all other radio work items are blocked during
1000 execution. Timeout is set to 10 seconds by default to avoid blocking
1001 wpa_supplicant operations for excessive time. If a longer (or shorter)
1002 safety timeout is needed, that can be specified with the optional
1003 timeout parameter. This command returns an identifier for the radio work
1006 Once the radio work item has been started, "EXT-RADIO-WORK-START <id>"
1007 event message is indicated that the external processing can start. Once
1008 the operation has been completed, "RADIO_WORK done <id>" is used to
1009 indicate that to wpa_supplicant. This allows other radio works to be
1010 performed. If this command is forgotten (e.g., due to the external
1011 program terminating), wpa_supplicant will time out the radio owrk item
1012 and send "EXT-RADIO-WORK-TIMEOUT <id>" event ot indicate that this has
1013 happened. "RADIO_WORK done <id>" can also be used to cancel items that
1014 have not yet been started.
1016 For example, in wpa_cli interactive mode:
1018 > radio_work add test
1020 <3>EXT-RADIO-WORK-START 1
1022 ext:test@wlan0:0:1:2.487797
1031 ext:test freq=2412 timeout=30@wlan0:2412:1:28.583483
1032 <3>EXT-RADIO-WORK-TIMEOUT 2
1035 > radio_work add test2 freq=2412 timeout=60
1037 <3>EXT-RADIO-WORK-START 5
1038 > radio_work add test3
1040 > radio_work add test4
1043 ext:test2 freq=2412 timeout=60@wlan0:2412:1:9.751844
1044 ext:test3@wlan0:0:0:5.071812
1045 ext:test4@wlan0:0:0:3.143870
1049 ext:test2 freq=2412 timeout=60@wlan0:2412:1:16.287869
1050 ext:test4@wlan0:0:0:9.679895
1053 <3>EXT-RADIO-WORK-START 7
1054 <3>EXT-RADIO-WORK-TIMEOUT 7