4 Copyright (c) 2003-2012, 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
34 derived from this software without specific prior written permission.
36 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
37 "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
38 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
39 A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
40 OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
41 SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
42 LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
43 DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
44 THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
45 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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 WPA/WPA2 configuration with the generic
119 Linux wireless extensions (WE-18 or newer). Even though there are
120 number of driver specific interface included in wpa_supplicant, please
121 note that Linux drivers are moving to use generic wireless extensions
122 and driver_wext (-Dwext on wpa_supplicant command line) should be the
123 default option to start with before falling back to driver specific
126 In theory, any driver that supports Linux wireless extensions can be
127 used with IEEE 802.1X (i.e., not WPA) when using ap_scan=0 option in
130 Wired Ethernet drivers (with ap_scan=0)
132 BSD net80211 layer (e.g., Atheros driver)
133 At the moment, this is for FreeBSD 6-CURRENT branch and NetBSD-current.
136 The current Windows port requires WinPcap (http://winpcap.polito.it/).
137 See README-Windows.txt for more information.
139 wpa_supplicant was designed to be portable for different drivers and
140 operating systems. Hopefully, support for more wlan cards and OSes will be
141 added in the future. See developer's documentation
142 (http://hostap.epitest.fi/wpa_supplicant/devel/) for more information about the
143 design of wpa_supplicant and porting to other drivers. One main goal
144 is to add full WPA/WPA2 support to Linux wireless extensions to allow
145 new drivers to be supported without having to implement new
146 driver-specific interface code in wpa_supplicant.
148 Optional libraries for layer2 packet processing:
149 - libpcap (tested with 0.7.2, most relatively recent versions assumed to work,
150 this is likely to be available with most distributions,
152 - libdnet (tested with v1.4, most versions assumed to work,
153 http://libdnet.sourceforge.net/)
155 These libraries are _not_ used in the default Linux build. Instead,
156 internal Linux specific implementation is used. libpcap/libdnet are
157 more portable and they can be used by adding CONFIG_L2_PACKET=pcap into
158 .config. They may also be selected automatically for other operating
159 systems. In case of Windows builds, WinPcap is used by default
160 (CONFIG_L2_PACKET=winpcap).
163 Optional libraries for EAP-TLS, EAP-PEAP, and EAP-TTLS:
164 - OpenSSL (tested with 0.9.7c and 0.9.7d, and 0.9.8 versions; assumed to
165 work with most relatively recent versions; this is likely to be
166 available with most distributions, http://www.openssl.org/)
168 - internal TLSv1 implementation
170 TLS options for EAP-FAST:
171 - OpenSSL 0.9.8d _with_ openssl-0.9.8d-tls-extensions.patch applied
172 (i.e., the default OpenSSL package does not include support for
173 extensions needed for EAP-FAST)
174 - internal TLSv1 implementation
176 One of these libraries is needed when EAP-TLS, EAP-PEAP, EAP-TTLS, or
177 EAP-FAST support is enabled. WPA-PSK mode does not require this or EAPOL/EAP
178 implementation. A configuration file, .config, for compilation is
179 needed to enable IEEE 802.1X/EAPOL and EAP methods. Note that EAP-MD5,
180 EAP-GTC, EAP-OTP, and EAP-MSCHAPV2 cannot be used alone with WPA, so
181 they should only be enabled if testing the EAPOL/EAP state
182 machines. However, there can be used as inner authentication
183 algorithms with EAP-PEAP and EAP-TTLS.
185 See Building and installing section below for more detailed
186 information about the wpa_supplicant build time configuration.
193 The original security mechanism of IEEE 802.11 standard was not
194 designed to be strong and has proven to be insufficient for most
195 networks that require some kind of security. Task group I (Security)
196 of IEEE 802.11 working group (http://www.ieee802.org/11/) has worked
197 to address the flaws of the base standard and has in practice
198 completed its work in May 2004. The IEEE 802.11i amendment to the IEEE
199 802.11 standard was approved in June 2004 and published in July 2004.
201 Wi-Fi Alliance (http://www.wi-fi.org/) used a draft version of the
202 IEEE 802.11i work (draft 3.0) to define a subset of the security
203 enhancements that can be implemented with existing wlan hardware. This
204 is called Wi-Fi Protected Access<TM> (WPA). This has now become a
205 mandatory component of interoperability testing and certification done
206 by Wi-Fi Alliance. Wi-Fi provides information about WPA at its web
207 site (http://www.wi-fi.org/OpenSection/protected_access.asp).
209 IEEE 802.11 standard defined wired equivalent privacy (WEP) algorithm
210 for protecting wireless networks. WEP uses RC4 with 40-bit keys,
211 24-bit initialization vector (IV), and CRC32 to protect against packet
212 forgery. All these choices have proven to be insufficient: key space is
213 too small against current attacks, RC4 key scheduling is insufficient
214 (beginning of the pseudorandom stream should be skipped), IV space is
215 too small and IV reuse makes attacks easier, there is no replay
216 protection, and non-keyed authentication does not protect against bit
217 flipping packet data.
219 WPA is an intermediate solution for the security issues. It uses
220 Temporal Key Integrity Protocol (TKIP) to replace WEP. TKIP is a
221 compromise on strong security and possibility to use existing
222 hardware. It still uses RC4 for the encryption like WEP, but with
223 per-packet RC4 keys. In addition, it implements replay protection,
224 keyed packet authentication mechanism (Michael MIC).
226 Keys can be managed using two different mechanisms. WPA can either use
227 an external authentication server (e.g., RADIUS) and EAP just like
228 IEEE 802.1X is using or pre-shared keys without need for additional
229 servers. Wi-Fi calls these "WPA-Enterprise" and "WPA-Personal",
230 respectively. Both mechanisms will generate a master session key for
231 the Authenticator (AP) and Supplicant (client station).
233 WPA implements a new key handshake (4-Way Handshake and Group Key
234 Handshake) for generating and exchanging data encryption keys between
235 the Authenticator and Supplicant. This handshake is also used to
236 verify that both Authenticator and Supplicant know the master session
237 key. These handshakes are identical regardless of the selected key
238 management mechanism (only the method for generating master session
246 The design for parts of IEEE 802.11i that were not included in WPA has
247 finished (May 2004) and this amendment to IEEE 802.11 was approved in
248 June 2004. Wi-Fi Alliance is using the final IEEE 802.11i as a new
249 version of WPA called WPA2. This includes, e.g., support for more
250 robust encryption algorithm (CCMP: AES in Counter mode with CBC-MAC)
251 to replace TKIP and optimizations for handoff (reduced number of
252 messages in initial key handshake, pre-authentication, and PMKSA caching).
259 wpa_supplicant is an implementation of the WPA Supplicant component,
260 i.e., the part that runs in the client stations. It implements WPA key
261 negotiation with a WPA Authenticator and EAP authentication with
262 Authentication Server. In addition, it controls the roaming and IEEE
263 802.11 authentication/association of the wlan driver.
265 wpa_supplicant is designed to be a "daemon" program that runs in the
266 background and acts as the backend component controlling the wireless
267 connection. wpa_supplicant supports separate frontend programs and an
268 example text-based frontend, wpa_cli, is included with wpa_supplicant.
270 Following steps are used when associating with an AP using WPA:
272 - wpa_supplicant requests the kernel driver to scan neighboring BSSes
273 - wpa_supplicant selects a BSS based on its configuration
274 - wpa_supplicant requests the kernel driver to associate with the chosen
276 - If WPA-EAP: integrated IEEE 802.1X Supplicant completes EAP
277 authentication with the authentication server (proxied by the
278 Authenticator in the AP)
279 - If WPA-EAP: master key is received from the IEEE 802.1X Supplicant
280 - If WPA-PSK: wpa_supplicant uses PSK as the master session key
281 - wpa_supplicant completes WPA 4-Way Handshake and Group Key Handshake
282 with the Authenticator (AP)
283 - wpa_supplicant configures encryption keys for unicast and broadcast
284 - normal data packets can be transmitted and received
288 Building and installing
289 -----------------------
291 In order to be able to build wpa_supplicant, you will first need to
292 select which parts of it will be included. This is done by creating a
293 build time configuration file, .config, in the wpa_supplicant root
294 directory. Configuration options are text lines using following
295 format: CONFIG_<option>=y. Lines starting with # are considered
296 comments and are ignored. See defconfig file for an example configuration
297 and a list of available options and additional notes.
299 The build time configuration can be used to select only the needed
300 features and limit the binary size and requirements for external
301 libraries. The main configuration parts are the selection of which
302 driver interfaces (e.g., nl80211, wext, ..) and which authentication
303 methods (e.g., EAP-TLS, EAP-PEAP, ..) are included.
305 Following build time configuration options are used to control IEEE
306 802.1X/EAPOL and EAP state machines and all EAP methods. Including
307 TLS, PEAP, or TTLS will require linking wpa_supplicant with OpenSSL
308 library for TLS implementation. Alternatively, GnuTLS or the internal
309 TLSv1 implementation can be used for TLS functionaly.
311 CONFIG_IEEE8021X_EAPOL=y
313 CONFIG_EAP_MSCHAPV2=y
328 Following option can be used to include GSM SIM/USIM interface for GSM/UMTS
329 authentication algorithm (for EAP-SIM/EAP-AKA). This requires pcsc-lite
330 (http://www.linuxnet.com/) for smart card access.
334 Following options can be added to .config to select which driver
335 interfaces are included.
337 CONFIG_DRIVER_NL80211=y
342 Following example includes some more features and driver interfaces that
343 are included in the wpa_supplicant package:
345 CONFIG_DRIVER_NL80211=y
349 CONFIG_IEEE8021X_EAPOL=y
351 CONFIG_EAP_MSCHAPV2=y
367 EAP-PEAP and EAP-TTLS will automatically include configured EAP
368 methods (MD5, OTP, GTC, MSCHAPV2) for inner authentication selection.
371 After you have created a configuration file, you can build
372 wpa_supplicant and wpa_cli with 'make' command. You may then install
373 the binaries to a suitable system directory, e.g., /usr/local/bin.
377 # build wpa_supplicant and wpa_cli
379 # install binaries (this may need root privileges)
380 cp wpa_cli wpa_supplicant /usr/local/bin
383 You will need to make a configuration file, e.g.,
384 /etc/wpa_supplicant.conf, with network configuration for the networks
385 you are going to use. Configuration file section below includes
386 explanation fo the configuration file format and includes various
387 examples. Once the configuration is ready, you can test whether the
388 configuration work by first running wpa_supplicant with following
389 command to start it on foreground with debugging enabled:
391 wpa_supplicant -iwlan0 -c/etc/wpa_supplicant.conf -d
393 Assuming everything goes fine, you can start using following command
394 to start wpa_supplicant on background without debugging:
396 wpa_supplicant -iwlan0 -c/etc/wpa_supplicant.conf -B
398 Please note that if you included more than one driver interface in the
399 build time configuration (.config), you may need to specify which
400 interface to use by including -D<driver name> option on the command
401 line. See following section for more details on command line options
410 wpa_supplicant [-BddfhKLqqtuvwW] [-P<pid file>] [-g<global ctrl>] \
411 -i<ifname> -c<config file> [-C<ctrl>] [-D<driver>] [-p<driver_param>] \
412 [-b<br_ifname> [-N -i<ifname> -c<conf> [-C<ctrl>] [-D<driver>] \
413 [-p<driver_param>] [-b<br_ifname>] ...]
416 -b = optional bridge interface name
417 -B = run daemon in the background
418 -c = Configuration file
419 -C = ctrl_interface parameter (only used if -c is not)
421 -d = increase debugging verbosity (-dd even more)
422 -D = driver name (can be multiple drivers: nl80211,wext)
423 -f = Log output to default log location (normally /tmp)
424 -g = global ctrl_interface
425 -K = include keys (passwords, etc.) in debug output
426 -t = include timestamp in debug messages
427 -h = show this help text
428 -L = show license (BSD)
429 -p = driver parameters
431 -q = decrease debugging verbosity (-qq even less)
432 -u = enable DBus control interface
434 -w = wait for interface to be added, if needed
435 -W = wait for a control interface monitor before starting
436 -N = start describing new interface
439 wext = Linux wireless extensions (generic)
440 wired = wpa_supplicant wired Ethernet driver
441 roboswitch = wpa_supplicant Broadcom switch driver
442 bsd = BSD 802.11 support (Atheros, etc.)
443 ndis = Windows NDIS driver
445 In most common cases, wpa_supplicant is started with
447 wpa_supplicant -B -c/etc/wpa_supplicant.conf -iwlan0
449 This makes the process fork into background.
451 The easiest way to debug problems, and to get debug log for bug
452 reports, is to start wpa_supplicant on foreground with debugging
455 wpa_supplicant -c/etc/wpa_supplicant.conf -iwlan0 -d
457 If the specific driver wrapper is not known beforehand, it is possible
458 to specify multiple comma separated driver wrappers on the command
459 line. wpa_supplicant will use the first driver wrapper that is able to
460 initialize the interface.
462 wpa_supplicant -Dnl80211,wext -c/etc/wpa_supplicant.conf -iwlan0
465 wpa_supplicant can control multiple interfaces (radios) either by
466 running one process for each interface separately or by running just
467 one process and list of options at command line. Each interface is
468 separated with -N argument. As an example, following command would
469 start wpa_supplicant for two interfaces:
472 -c wpa1.conf -i wlan0 -D nl80211 -N \
473 -c wpa2.conf -i wlan1 -D wext
476 If the interface is added in a Linux bridge (e.g., br0), the bridge
477 interface needs to be configured to wpa_supplicant in addition to the
480 wpa_supplicant -cw.conf -Dwext -iwlan0 -bbr0
486 wpa_supplicant is configured using a text file that lists all accepted
487 networks and security policies, including pre-shared keys. See
488 example configuration file, wpa_supplicant.conf, for detailed
489 information about the configuration format and supported fields.
491 Changes to configuration file can be reloaded be sending SIGHUP signal
492 to wpa_supplicant ('killall -HUP wpa_supplicant'). Similarly,
493 reloading can be triggered with 'wpa_cli reconfigure' command.
495 Configuration file can include one or more network blocks, e.g., one
496 for each used SSID. wpa_supplicant will automatically select the best
497 betwork based on the order of network blocks in the configuration
498 file, network security level (WPA/WPA2 is preferred), and signal
501 Example configuration files for some common configurations:
503 1) WPA-Personal (PSK) as home network and WPA-Enterprise with EAP-TLS as work
506 # allow frontend (e.g., wpa_cli) to be used by all users in 'wheel' group
507 ctrl_interface=/var/run/wpa_supplicant
508 ctrl_interface_group=wheel
510 # home network; allow all valid ciphers
515 psk="very secret passphrase"
518 # work network; use EAP-TLS with WPA; allow only CCMP and TKIP ciphers
526 identity="user@example.com"
527 ca_cert="/etc/cert/ca.pem"
528 client_cert="/etc/cert/user.pem"
529 private_key="/etc/cert/user.prv"
530 private_key_passwd="password"
534 2) WPA-RADIUS/EAP-PEAP/MSCHAPv2 with RADIUS servers that use old peaplabel
535 (e.g., Funk Odyssey and SBR, Meetinghouse Aegis, Interlink RAD-Series)
537 ctrl_interface=/var/run/wpa_supplicant
538 ctrl_interface_group=wheel
544 identity="user@example.com"
546 ca_cert="/etc/cert/ca.pem"
548 phase2="auth=MSCHAPV2"
552 3) EAP-TTLS/EAP-MD5-Challenge configuration with anonymous identity for the
553 unencrypted use. Real identity is sent only within an encrypted TLS tunnel.
555 ctrl_interface=/var/run/wpa_supplicant
556 ctrl_interface_group=wheel
562 identity="user@example.com"
563 anonymous_identity="anonymous@example.com"
565 ca_cert="/etc/cert/ca.pem"
570 4) IEEE 802.1X (i.e., no WPA) with dynamic WEP keys (require both unicast and
571 broadcast); use EAP-TLS for authentication
573 ctrl_interface=/var/run/wpa_supplicant
574 ctrl_interface_group=wheel
580 identity="user@example.com"
581 ca_cert="/etc/cert/ca.pem"
582 client_cert="/etc/cert/user.pem"
583 private_key="/etc/cert/user.prv"
584 private_key_passwd="password"
589 5) Catch all example that allows more or less all configuration modes. The
590 configuration options are used based on what security policy is used in the
591 selected SSID. This is mostly for testing and is not recommended for normal
594 ctrl_interface=/var/run/wpa_supplicant
595 ctrl_interface_group=wheel
599 key_mgmt=WPA-EAP WPA-PSK IEEE8021X NONE
601 group=CCMP TKIP WEP104 WEP40
602 psk="very secret passphrase"
604 identity="user@example.com"
606 ca_cert="/etc/cert/ca.pem"
607 client_cert="/etc/cert/user.pem"
608 private_key="/etc/cert/user.prv"
609 private_key_passwd="password"
611 ca_cert2="/etc/cert/ca2.pem"
612 client_cert2="/etc/cer/user.pem"
613 private_key2="/etc/cer/user.prv"
614 private_key2_passwd="password"
618 6) Authentication for wired Ethernet. This can be used with 'wired' or
619 'roboswitch' interface (-Dwired or -Droboswitch on command line).
621 ctrl_interface=/var/run/wpa_supplicant
622 ctrl_interface_group=wheel
637 Some EAP authentication methods require use of certificates. EAP-TLS
638 uses both server side and client certificates whereas EAP-PEAP and
639 EAP-TTLS only require the server side certificate. When client
640 certificate is used, a matching private key file has to also be
641 included in configuration. If the private key uses a passphrase, this
642 has to be configured in wpa_supplicant.conf ("private_key_passwd").
644 wpa_supplicant supports X.509 certificates in PEM and DER
645 formats. User certificate and private key can be included in the same
648 If the user certificate and private key is received in PKCS#12/PFX
649 format, they need to be converted to suitable PEM/DER format for
650 wpa_supplicant. This can be done, e.g., with following commands:
652 # convert client certificate and private key to PEM format
653 openssl pkcs12 -in example.pfx -out user.pem -clcerts
654 # convert CA certificate (if included in PFX file) to PEM format
655 openssl pkcs12 -in example.pfx -out ca.pem -cacerts -nokeys
662 wpa_cli is a text-based frontend program for interacting with
663 wpa_supplicant. It is used to query current status, change
664 configuration, trigger events, and request interactive user input.
666 wpa_cli can show the current authentication status, selected security
667 mode, dot11 and dot1x MIBs, etc. In addition, it can configure some
668 variables like EAPOL state machine parameters and trigger events like
669 reassociation and IEEE 802.1X logoff/logon. wpa_cli provides a user
670 interface to request authentication information, like username and
671 password, if these are not included in the configuration. This can be
672 used to implement, e.g., one-time-passwords or generic token card
673 authentication where the authentication is based on a
674 challenge-response that uses an external device for generating the
677 The control interface of wpa_supplicant can be configured to allow
678 non-root user access (ctrl_interface_group in the configuration
679 file). This makes it possible to run wpa_cli with a normal user
682 wpa_cli supports two modes: interactive and command line. Both modes
683 share the same command set and the main difference is in interactive
684 mode providing access to unsolicited messages (event messages,
685 username/password requests).
687 Interactive mode is started when wpa_cli is executed without including
688 the command as a command line parameter. Commands are then entered on
689 the wpa_cli prompt. In command line mode, the same commands are
690 entered as command line arguments for wpa_cli.
693 Interactive authentication parameters request
695 When wpa_supplicant need authentication parameters, like username and
696 password, which are not present in the configuration file, it sends a
697 request message to all attached frontend programs, e.g., wpa_cli in
698 interactive mode. wpa_cli shows these requests with
699 "CTRL-REQ-<type>-<id>:<text>" prefix. <type> is IDENTITY, PASSWORD, or
700 OTP (one-time-password). <id> is a unique identifier for the current
701 network. <text> is description of the request. In case of OTP request,
702 it includes the challenge from the authentication server.
704 The reply to these requests can be given with 'identity', 'password',
705 and 'otp' commands. <id> needs to be copied from the the matching
706 request. 'password' and 'otp' commands can be used regardless of
707 whether the request was for PASSWORD or OTP. The main difference
708 between these two commands is that values given with 'password' are
709 remembered as long as wpa_supplicant is running whereas values given
710 with 'otp' are used only once and then forgotten, i.e., wpa_supplicant
711 will ask frontend for a new value for every use. This can be used to
712 implement one-time-password lists and generic token card -based
715 Example request for password and a matching reply:
717 CTRL-REQ-PASSWORD-1:Password needed for SSID foobar
718 > password 1 mysecretpassword
720 Example request for generic token card challenge-response:
722 CTRL-REQ-OTP-2:Challenge 1235663 needed for SSID foobar
728 status = get current WPA/EAPOL/EAP status
729 mib = get MIB variables (dot1x, dot11)
730 help = show this usage help
731 interface [ifname] = show interfaces/select interface
732 level <debug level> = change debug level
733 license = show full wpa_cli license
734 logoff = IEEE 802.1X EAPOL state machine logoff
735 logon = IEEE 802.1X EAPOL state machine logon
736 set = set variables (shows list of variables when run without arguments)
737 pmksa = show PMKSA cache
738 reassociate = force reassociation
739 reconfigure = force wpa_supplicant to re-read its configuration file
740 preauthenticate <BSSID> = force preauthentication
741 identity <network id> <identity> = configure identity for an SSID
742 password <network id> <password> = configure password for an SSID
743 pin <network id> <pin> = configure pin for an SSID
744 otp <network id> <password> = configure one-time-password for an SSID
745 passphrase <network id> <passphrase> = configure private key passphrase
747 bssid <network id> <BSSID> = set preferred BSSID for an SSID
748 list_networks = list configured networks
749 select_network <network id> = select a network (disable others)
750 enable_network <network id> = enable a network
751 disable_network <network id> = disable a network
752 add_network = add a network
753 remove_network <network id> = remove a network
754 set_network <network id> <variable> <value> = set network variables (shows
755 list of variables when run without arguments)
756 get_network <network id> <variable> = get network variables
757 save_config = save the current configuration
758 disconnect = disconnect and wait for reassociate command before connecting
759 scan = request new BSS scan
760 scan_results = get latest scan results
761 get_capability <eap/pairwise/group/key_mgmt/proto/auth_alg> = get capabilies
762 terminate = terminate wpa_supplicant
766 wpa_cli command line options
768 wpa_cli [-p<path to ctrl sockets>] [-i<ifname>] [-hvB] [-a<action file>] \
769 [-P<pid file>] [-g<global ctrl>] [command..]
770 -h = help (show this usage text)
771 -v = shown version information
772 -a = run in daemon mode executing the action file based on events from
774 -B = run a daemon in the background
775 default path: /var/run/wpa_supplicant
776 default interface: first interface found in socket path
779 Using wpa_cli to run external program on connect/disconnect
780 -----------------------------------------------------------
782 wpa_cli can used to run external programs whenever wpa_supplicant
783 connects or disconnects from a network. This can be used, e.g., to
784 update network configuration and/or trigget DHCP client to update IP
787 One wpa_cli process in "action" mode needs to be started for each
788 interface. For example, the following command starts wpa_cli for the
789 default ingterface (-i can be used to select the interface in case of
790 more than one interface being used at the same time):
792 wpa_cli -a/sbin/wpa_action.sh -B
794 The action file (-a option, /sbin/wpa_action.sh in this example) will
795 be executed whenever wpa_supplicant completes authentication (connect
796 event) or detects disconnection). The action script will be called
797 with two command line arguments: interface name and event (CONNECTED
798 or DISCONNECTED). If the action script needs to get more information
799 about the current network, it can use 'wpa_cli status' to query
800 wpa_supplicant for more information.
802 Following example can be used as a simple template for an action
810 if [ "$CMD" = "CONNECTED" ]; then
811 SSID=`wpa_cli -i$IFNAME status | grep ^ssid= | cut -f2- -d=`
812 # configure network, signal DHCP client, etc.
815 if [ "$CMD" = "DISCONNECTED" ]; then
816 # remove network configuration, if needed
822 Integrating with pcmcia-cs/cardmgr scripts
823 ------------------------------------------
825 wpa_supplicant needs to be running when using a wireless network with
826 WPA. It can be started either from system startup scripts or from
827 pcmcia-cs/cardmgr scripts (when using PC Cards). WPA handshake must be
828 completed before data frames can be exchanged, so wpa_supplicant
829 should be started before DHCP client.
831 For example, following small changes to pcmcia-cs scripts can be used
832 to enable WPA support:
834 Add MODE="Managed" and WPA="y" to the network scheme in
835 /etc/pcmcia/wireless.opts.
837 Add the following block to the end of 'start' action handler in
838 /etc/pcmcia/wireless:
840 if [ "$WPA" = "y" -a -x /usr/local/bin/wpa_supplicant ]; then
841 /usr/local/bin/wpa_supplicant -B -c/etc/wpa_supplicant.conf \
845 Add the following block to the end of 'stop' action handler (may need
846 to be separated from other actions) in /etc/pcmcia/wireless:
848 if [ "$WPA" = "y" -a -x /usr/local/bin/wpa_supplicant ]; then
849 killall wpa_supplicant
852 This will make cardmgr start wpa_supplicant when the card is plugged
857 Dynamic interface add and operation without configuration files
858 ---------------------------------------------------------------
860 wpa_supplicant can be started without any configuration files or
861 network interfaces. When used in this way, a global (i.e., per
862 wpa_supplicant process) control interface is used to add and remove
863 network interfaces. Each network interface can then be configured
864 through a per-network interface control interface. For example,
865 following commands show how to start wpa_supplicant without any
866 network interfaces and then add a network interface and configure a
869 # Start wpa_supplicant in the background
870 wpa_supplicant -g/var/run/wpa_supplicant-global -B
872 # Add a new interface (wlan0, no configuration file, driver=wext, and
873 # enable control interface)
874 wpa_cli -g/var/run/wpa_supplicant-global interface_add wlan0 \
875 "" wext /var/run/wpa_supplicant
877 # Configure a network using the newly added network interface:
878 wpa_cli -iwlan0 add_network
879 wpa_cli -iwlan0 set_network 0 ssid '"test"'
880 wpa_cli -iwlan0 set_network 0 key_mgmt WPA-PSK
881 wpa_cli -iwlan0 set_network 0 psk '"12345678"'
882 wpa_cli -iwlan0 set_network 0 pairwise TKIP
883 wpa_cli -iwlan0 set_network 0 group TKIP
884 wpa_cli -iwlan0 set_network 0 proto WPA
885 wpa_cli -iwlan0 enable_network 0
887 # At this point, the new network interface should start trying to associate
888 # with the WPA-PSK network using SSID test.
890 # Remove network interface
891 wpa_cli -g/var/run/wpa_supplicant-global interface_remove wlan0
897 To minimize the size of code that needs to be run with root privileges
898 (e.g., to control wireless interface operation), wpa_supplicant
899 supports optional privilege separation. If enabled, this separates the
900 privileged operations into a separate process (wpa_priv) while leaving
901 rest of the code (e.g., EAP authentication and WPA handshakes) into an
902 unprivileged process (wpa_supplicant) that can be run as non-root
903 user. Privilege separation restricts the effects of potential software
904 errors by containing the majority of the code in an unprivileged
905 process to avoid full system compromise.
907 Privilege separation is not enabled by default and it can be enabled
908 by adding CONFIG_PRIVSEP=y to the build configuration (.config). When
909 enabled, the privileged operations (driver wrapper and l2_packet) are
910 linked into a separate daemon program, wpa_priv. The unprivileged
911 program, wpa_supplicant, will be built with a special driver/l2_packet
912 wrappers that communicate with the privileged wpa_priv process to
913 perform the needed operations. wpa_priv can control what privileged
916 wpa_priv needs to be run with network admin privileges (usually, root
917 user). It opens a UNIX domain socket for each interface that is
918 included on the command line; any other interface will be off limits
919 for wpa_supplicant in this kind of configuration. After this,
920 wpa_supplicant can be run as a non-root user (e.g., all standard users
921 on a laptop or as a special non-privileged user account created just
922 for this purpose to limit access to user files even further).
925 Example configuration:
926 - create user group for users that are allowed to use wpa_supplicant
927 ('wpapriv' in this example) and assign users that should be able to
928 use wpa_supplicant into that group
929 - create /var/run/wpa_priv directory for UNIX domain sockets and control
930 user access by setting it accessible only for the wpapriv group:
931 mkdir /var/run/wpa_priv
932 chown root:wpapriv /var/run/wpa_priv
933 chmod 0750 /var/run/wpa_priv
934 - start wpa_priv as root (e.g., from system startup scripts) with the
935 enabled interfaces configured on the command line:
936 wpa_priv -B -P /var/run/wpa_priv.pid wext:ath0
937 - run wpa_supplicant as non-root with a user that is in wpapriv group:
938 wpa_supplicant -i ath0 -c wpa_supplicant.conf
940 wpa_priv does not use the network interface before wpa_supplicant is
941 started, so it is fine to include network interfaces that are not
942 available at the time wpa_priv is started. As an alternative, wpa_priv
943 can be started when an interface is added (hotplug/udev/etc. scripts).
944 wpa_priv can control multiple interface with one process, but it is
945 also possible to run multiple wpa_priv processes at the same time, if