4 Copyright (c) 2003-2011, 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
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48 names of its contributors may be used to endorse or promote products
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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 In theory, any driver that supports Linux wireless extensions can be
142 used with IEEE 802.1X (i.e., not WPA) when using ap_scan=0 option in
145 Wired Ethernet drivers (with ap_scan=0)
147 BSD net80211 layer (e.g., Atheros driver)
148 At the moment, this is for FreeBSD 6-CURRENT branch and NetBSD-current.
151 The current Windows port requires WinPcap (http://winpcap.polito.it/).
152 See README-Windows.txt for more information.
154 wpa_supplicant was designed to be portable for different drivers and
155 operating systems. Hopefully, support for more wlan cards and OSes will be
156 added in the future. See developer's documentation
157 (http://hostap.epitest.fi/wpa_supplicant/devel/) for more information about the
158 design of wpa_supplicant and porting to other drivers. One main goal
159 is to add full WPA/WPA2 support to Linux wireless extensions to allow
160 new drivers to be supported without having to implement new
161 driver-specific interface code in wpa_supplicant.
163 Optional libraries for layer2 packet processing:
164 - libpcap (tested with 0.7.2, most relatively recent versions assumed to work,
165 this is likely to be available with most distributions,
167 - libdnet (tested with v1.4, most versions assumed to work,
168 http://libdnet.sourceforge.net/)
170 These libraries are _not_ used in the default Linux build. Instead,
171 internal Linux specific implementation is used. libpcap/libdnet are
172 more portable and they can be used by adding CONFIG_L2_PACKET=pcap into
173 .config. They may also be selected automatically for other operating
174 systems. In case of Windows builds, WinPcap is used by default
175 (CONFIG_L2_PACKET=winpcap).
178 Optional libraries for EAP-TLS, EAP-PEAP, and EAP-TTLS:
179 - OpenSSL (tested with 0.9.7c and 0.9.7d, and 0.9.8 versions; assumed to
180 work with most relatively recent versions; this is likely to be
181 available with most distributions, http://www.openssl.org/)
183 - internal TLSv1 implementation
185 TLS options for EAP-FAST:
186 - OpenSSL 0.9.8d _with_ openssl-0.9.8d-tls-extensions.patch applied
187 (i.e., the default OpenSSL package does not include support for
188 extensions needed for EAP-FAST)
189 - internal TLSv1 implementation
191 One of these libraries is needed when EAP-TLS, EAP-PEAP, EAP-TTLS, or
192 EAP-FAST support is enabled. WPA-PSK mode does not require this or EAPOL/EAP
193 implementation. A configuration file, .config, for compilation is
194 needed to enable IEEE 802.1X/EAPOL and EAP methods. Note that EAP-MD5,
195 EAP-GTC, EAP-OTP, and EAP-MSCHAPV2 cannot be used alone with WPA, so
196 they should only be enabled if testing the EAPOL/EAP state
197 machines. However, there can be used as inner authentication
198 algorithms with EAP-PEAP and EAP-TTLS.
200 See Building and installing section below for more detailed
201 information about the wpa_supplicant build time configuration.
208 The original security mechanism of IEEE 802.11 standard was not
209 designed to be strong and has proven to be insufficient for most
210 networks that require some kind of security. Task group I (Security)
211 of IEEE 802.11 working group (http://www.ieee802.org/11/) has worked
212 to address the flaws of the base standard and has in practice
213 completed its work in May 2004. The IEEE 802.11i amendment to the IEEE
214 802.11 standard was approved in June 2004 and published in July 2004.
216 Wi-Fi Alliance (http://www.wi-fi.org/) used a draft version of the
217 IEEE 802.11i work (draft 3.0) to define a subset of the security
218 enhancements that can be implemented with existing wlan hardware. This
219 is called Wi-Fi Protected Access<TM> (WPA). This has now become a
220 mandatory component of interoperability testing and certification done
221 by Wi-Fi Alliance. Wi-Fi provides information about WPA at its web
222 site (http://www.wi-fi.org/OpenSection/protected_access.asp).
224 IEEE 802.11 standard defined wired equivalent privacy (WEP) algorithm
225 for protecting wireless networks. WEP uses RC4 with 40-bit keys,
226 24-bit initialization vector (IV), and CRC32 to protect against packet
227 forgery. All these choices have proven to be insufficient: key space is
228 too small against current attacks, RC4 key scheduling is insufficient
229 (beginning of the pseudorandom stream should be skipped), IV space is
230 too small and IV reuse makes attacks easier, there is no replay
231 protection, and non-keyed authentication does not protect against bit
232 flipping packet data.
234 WPA is an intermediate solution for the security issues. It uses
235 Temporal Key Integrity Protocol (TKIP) to replace WEP. TKIP is a
236 compromise on strong security and possibility to use existing
237 hardware. It still uses RC4 for the encryption like WEP, but with
238 per-packet RC4 keys. In addition, it implements replay protection,
239 keyed packet authentication mechanism (Michael MIC).
241 Keys can be managed using two different mechanisms. WPA can either use
242 an external authentication server (e.g., RADIUS) and EAP just like
243 IEEE 802.1X is using or pre-shared keys without need for additional
244 servers. Wi-Fi calls these "WPA-Enterprise" and "WPA-Personal",
245 respectively. Both mechanisms will generate a master session key for
246 the Authenticator (AP) and Supplicant (client station).
248 WPA implements a new key handshake (4-Way Handshake and Group Key
249 Handshake) for generating and exchanging data encryption keys between
250 the Authenticator and Supplicant. This handshake is also used to
251 verify that both Authenticator and Supplicant know the master session
252 key. These handshakes are identical regardless of the selected key
253 management mechanism (only the method for generating master session
261 The design for parts of IEEE 802.11i that were not included in WPA has
262 finished (May 2004) and this amendment to IEEE 802.11 was approved in
263 June 2004. Wi-Fi Alliance is using the final IEEE 802.11i as a new
264 version of WPA called WPA2. This includes, e.g., support for more
265 robust encryption algorithm (CCMP: AES in Counter mode with CBC-MAC)
266 to replace TKIP and optimizations for handoff (reduced number of
267 messages in initial key handshake, pre-authentication, and PMKSA caching).
274 wpa_supplicant is an implementation of the WPA Supplicant component,
275 i.e., the part that runs in the client stations. It implements WPA key
276 negotiation with a WPA Authenticator and EAP authentication with
277 Authentication Server. In addition, it controls the roaming and IEEE
278 802.11 authentication/association of the wlan driver.
280 wpa_supplicant is designed to be a "daemon" program that runs in the
281 background and acts as the backend component controlling the wireless
282 connection. wpa_supplicant supports separate frontend programs and an
283 example text-based frontend, wpa_cli, is included with wpa_supplicant.
285 Following steps are used when associating with an AP using WPA:
287 - wpa_supplicant requests the kernel driver to scan neighboring BSSes
288 - wpa_supplicant selects a BSS based on its configuration
289 - wpa_supplicant requests the kernel driver to associate with the chosen
291 - If WPA-EAP: integrated IEEE 802.1X Supplicant completes EAP
292 authentication with the authentication server (proxied by the
293 Authenticator in the AP)
294 - If WPA-EAP: master key is received from the IEEE 802.1X Supplicant
295 - If WPA-PSK: wpa_supplicant uses PSK as the master session key
296 - wpa_supplicant completes WPA 4-Way Handshake and Group Key Handshake
297 with the Authenticator (AP)
298 - wpa_supplicant configures encryption keys for unicast and broadcast
299 - normal data packets can be transmitted and received
303 Building and installing
304 -----------------------
306 In order to be able to build wpa_supplicant, you will first need to
307 select which parts of it will be included. This is done by creating a
308 build time configuration file, .config, in the wpa_supplicant root
309 directory. Configuration options are text lines using following
310 format: CONFIG_<option>=y. Lines starting with # are considered
311 comments and are ignored. See defconfig file for an example configuration
312 and a list of available options and additional notes.
314 The build time configuration can be used to select only the needed
315 features and limit the binary size and requirements for external
316 libraries. The main configuration parts are the selection of which
317 driver interfaces (e.g., nl80211, wext, ..) and which authentication
318 methods (e.g., EAP-TLS, EAP-PEAP, ..) are included.
320 Following build time configuration options are used to control IEEE
321 802.1X/EAPOL and EAP state machines and all EAP methods. Including
322 TLS, PEAP, or TTLS will require linking wpa_supplicant with OpenSSL
323 library for TLS implementation. Alternatively, GnuTLS or the internal
324 TLSv1 implementation can be used for TLS functionaly.
326 CONFIG_IEEE8021X_EAPOL=y
328 CONFIG_EAP_MSCHAPV2=y
343 Following option can be used to include GSM SIM/USIM interface for GSM/UMTS
344 authentication algorithm (for EAP-SIM/EAP-AKA). This requires pcsc-lite
345 (http://www.linuxnet.com/) for smart card access.
349 Following options can be added to .config to select which driver
350 interfaces are included.
352 CONFIG_DRIVER_NL80211=y
357 Following example includes some more features and driver interfaces that
358 are included in the wpa_supplicant package:
360 CONFIG_DRIVER_NL80211=y
364 CONFIG_IEEE8021X_EAPOL=y
366 CONFIG_EAP_MSCHAPV2=y
382 EAP-PEAP and EAP-TTLS will automatically include configured EAP
383 methods (MD5, OTP, GTC, MSCHAPV2) for inner authentication selection.
386 After you have created a configuration file, you can build
387 wpa_supplicant and wpa_cli with 'make' command. You may then install
388 the binaries to a suitable system directory, e.g., /usr/local/bin.
392 # build wpa_supplicant and wpa_cli
394 # install binaries (this may need root privileges)
395 cp wpa_cli wpa_supplicant /usr/local/bin
398 You will need to make a configuration file, e.g.,
399 /etc/wpa_supplicant.conf, with network configuration for the networks
400 you are going to use. Configuration file section below includes
401 explanation fo the configuration file format and includes various
402 examples. Once the configuration is ready, you can test whether the
403 configuration work by first running wpa_supplicant with following
404 command to start it on foreground with debugging enabled:
406 wpa_supplicant -iwlan0 -c/etc/wpa_supplicant.conf -d
408 Assuming everything goes fine, you can start using following command
409 to start wpa_supplicant on background without debugging:
411 wpa_supplicant -iwlan0 -c/etc/wpa_supplicant.conf -B
413 Please note that if you included more than one driver interface in the
414 build time configuration (.config), you may need to specify which
415 interface to use by including -D<driver name> option on the command
416 line. See following section for more details on command line options
425 wpa_supplicant [-BddfhKLqqtuvwW] [-P<pid file>] [-g<global ctrl>] \
426 -i<ifname> -c<config file> [-C<ctrl>] [-D<driver>] [-p<driver_param>] \
427 [-b<br_ifname> [-N -i<ifname> -c<conf> [-C<ctrl>] [-D<driver>] \
428 [-p<driver_param>] [-b<br_ifname>] ...]
431 -b = optional bridge interface name
432 -B = run daemon in the background
433 -c = Configuration file
434 -C = ctrl_interface parameter (only used if -c is not)
436 -d = increase debugging verbosity (-dd even more)
437 -D = driver name (can be multiple drivers: nl80211,wext)
438 -f = Log output to default log location (normally /tmp)
439 -g = global ctrl_interface
440 -K = include keys (passwords, etc.) in debug output
441 -t = include timestamp in debug messages
442 -h = show this help text
443 -L = show license (GPL and BSD)
444 -p = driver parameters
446 -q = decrease debugging verbosity (-qq even less)
447 -u = enable DBus control interface
449 -w = wait for interface to be added, if needed
450 -W = wait for a control interface monitor before starting
451 -N = start describing new interface
454 wext = Linux wireless extensions (generic)
455 wired = wpa_supplicant wired Ethernet driver
456 roboswitch = wpa_supplicant Broadcom switch driver
457 bsd = BSD 802.11 support (Atheros, etc.)
458 ndis = Windows NDIS driver
460 In most common cases, wpa_supplicant is started with
462 wpa_supplicant -B -c/etc/wpa_supplicant.conf -iwlan0
464 This makes the process fork into background.
466 The easiest way to debug problems, and to get debug log for bug
467 reports, is to start wpa_supplicant on foreground with debugging
470 wpa_supplicant -c/etc/wpa_supplicant.conf -iwlan0 -d
472 If the specific driver wrapper is not known beforehand, it is possible
473 to specify multiple comma separated driver wrappers on the command
474 line. wpa_supplicant will use the first driver wrapper that is able to
475 initialize the interface.
477 wpa_supplicant -Dnl80211,wext -c/etc/wpa_supplicant.conf -iwlan0
480 wpa_supplicant can control multiple interfaces (radios) either by
481 running one process for each interface separately or by running just
482 one process and list of options at command line. Each interface is
483 separated with -N argument. As an example, following command would
484 start wpa_supplicant for two interfaces:
487 -c wpa1.conf -i wlan0 -D nl80211 -N \
488 -c wpa2.conf -i wlan1 -D wext
491 If the interface is added in a Linux bridge (e.g., br0), the bridge
492 interface needs to be configured to wpa_supplicant in addition to the
495 wpa_supplicant -cw.conf -Dwext -iwlan0 -bbr0
501 wpa_supplicant is configured using a text file that lists all accepted
502 networks and security policies, including pre-shared keys. See
503 example configuration file, wpa_supplicant.conf, for detailed
504 information about the configuration format and supported fields.
506 Changes to configuration file can be reloaded be sending SIGHUP signal
507 to wpa_supplicant ('killall -HUP wpa_supplicant'). Similarly,
508 reloading can be triggered with 'wpa_cli reconfigure' command.
510 Configuration file can include one or more network blocks, e.g., one
511 for each used SSID. wpa_supplicant will automatically select the best
512 betwork based on the order of network blocks in the configuration
513 file, network security level (WPA/WPA2 is preferred), and signal
516 Example configuration files for some common configurations:
518 1) WPA-Personal (PSK) as home network and WPA-Enterprise with EAP-TLS as work
521 # allow frontend (e.g., wpa_cli) to be used by all users in 'wheel' group
522 ctrl_interface=/var/run/wpa_supplicant
523 ctrl_interface_group=wheel
525 # home network; allow all valid ciphers
530 psk="very secret passphrase"
533 # work network; use EAP-TLS with WPA; allow only CCMP and TKIP ciphers
541 identity="user@example.com"
542 ca_cert="/etc/cert/ca.pem"
543 client_cert="/etc/cert/user.pem"
544 private_key="/etc/cert/user.prv"
545 private_key_passwd="password"
549 2) WPA-RADIUS/EAP-PEAP/MSCHAPv2 with RADIUS servers that use old peaplabel
550 (e.g., Funk Odyssey and SBR, Meetinghouse Aegis, Interlink RAD-Series)
552 ctrl_interface=/var/run/wpa_supplicant
553 ctrl_interface_group=wheel
559 identity="user@example.com"
561 ca_cert="/etc/cert/ca.pem"
563 phase2="auth=MSCHAPV2"
567 3) EAP-TTLS/EAP-MD5-Challenge configuration with anonymous identity for the
568 unencrypted use. Real identity is sent only within an encrypted TLS tunnel.
570 ctrl_interface=/var/run/wpa_supplicant
571 ctrl_interface_group=wheel
577 identity="user@example.com"
578 anonymous_identity="anonymous@example.com"
580 ca_cert="/etc/cert/ca.pem"
585 4) IEEE 802.1X (i.e., no WPA) with dynamic WEP keys (require both unicast and
586 broadcast); use EAP-TLS for authentication
588 ctrl_interface=/var/run/wpa_supplicant
589 ctrl_interface_group=wheel
595 identity="user@example.com"
596 ca_cert="/etc/cert/ca.pem"
597 client_cert="/etc/cert/user.pem"
598 private_key="/etc/cert/user.prv"
599 private_key_passwd="password"
604 5) Catch all example that allows more or less all configuration modes. The
605 configuration options are used based on what security policy is used in the
606 selected SSID. This is mostly for testing and is not recommended for normal
609 ctrl_interface=/var/run/wpa_supplicant
610 ctrl_interface_group=wheel
614 key_mgmt=WPA-EAP WPA-PSK IEEE8021X NONE
616 group=CCMP TKIP WEP104 WEP40
617 psk="very secret passphrase"
619 identity="user@example.com"
621 ca_cert="/etc/cert/ca.pem"
622 client_cert="/etc/cert/user.pem"
623 private_key="/etc/cert/user.prv"
624 private_key_passwd="password"
626 ca_cert2="/etc/cert/ca2.pem"
627 client_cert2="/etc/cer/user.pem"
628 private_key2="/etc/cer/user.prv"
629 private_key2_passwd="password"
633 6) Authentication for wired Ethernet. This can be used with 'wired' or
634 'roboswitch' interface (-Dwired or -Droboswitch on command line).
636 ctrl_interface=/var/run/wpa_supplicant
637 ctrl_interface_group=wheel
652 Some EAP authentication methods require use of certificates. EAP-TLS
653 uses both server side and client certificates whereas EAP-PEAP and
654 EAP-TTLS only require the server side certificate. When client
655 certificate is used, a matching private key file has to also be
656 included in configuration. If the private key uses a passphrase, this
657 has to be configured in wpa_supplicant.conf ("private_key_passwd").
659 wpa_supplicant supports X.509 certificates in PEM and DER
660 formats. User certificate and private key can be included in the same
663 If the user certificate and private key is received in PKCS#12/PFX
664 format, they need to be converted to suitable PEM/DER format for
665 wpa_supplicant. This can be done, e.g., with following commands:
667 # convert client certificate and private key to PEM format
668 openssl pkcs12 -in example.pfx -out user.pem -clcerts
669 # convert CA certificate (if included in PFX file) to PEM format
670 openssl pkcs12 -in example.pfx -out ca.pem -cacerts -nokeys
677 wpa_cli is a text-based frontend program for interacting with
678 wpa_supplicant. It is used to query current status, change
679 configuration, trigger events, and request interactive user input.
681 wpa_cli can show the current authentication status, selected security
682 mode, dot11 and dot1x MIBs, etc. In addition, it can configure some
683 variables like EAPOL state machine parameters and trigger events like
684 reassociation and IEEE 802.1X logoff/logon. wpa_cli provides a user
685 interface to request authentication information, like username and
686 password, if these are not included in the configuration. This can be
687 used to implement, e.g., one-time-passwords or generic token card
688 authentication where the authentication is based on a
689 challenge-response that uses an external device for generating the
692 The control interface of wpa_supplicant can be configured to allow
693 non-root user access (ctrl_interface_group in the configuration
694 file). This makes it possible to run wpa_cli with a normal user
697 wpa_cli supports two modes: interactive and command line. Both modes
698 share the same command set and the main difference is in interactive
699 mode providing access to unsolicited messages (event messages,
700 username/password requests).
702 Interactive mode is started when wpa_cli is executed without including
703 the command as a command line parameter. Commands are then entered on
704 the wpa_cli prompt. In command line mode, the same commands are
705 entered as command line arguments for wpa_cli.
708 Interactive authentication parameters request
710 When wpa_supplicant need authentication parameters, like username and
711 password, which are not present in the configuration file, it sends a
712 request message to all attached frontend programs, e.g., wpa_cli in
713 interactive mode. wpa_cli shows these requests with
714 "CTRL-REQ-<type>-<id>:<text>" prefix. <type> is IDENTITY, PASSWORD, or
715 OTP (one-time-password). <id> is a unique identifier for the current
716 network. <text> is description of the request. In case of OTP request,
717 it includes the challenge from the authentication server.
719 The reply to these requests can be given with 'identity', 'password',
720 and 'otp' commands. <id> needs to be copied from the the matching
721 request. 'password' and 'otp' commands can be used regardless of
722 whether the request was for PASSWORD or OTP. The main difference
723 between these two commands is that values given with 'password' are
724 remembered as long as wpa_supplicant is running whereas values given
725 with 'otp' are used only once and then forgotten, i.e., wpa_supplicant
726 will ask frontend for a new value for every use. This can be used to
727 implement one-time-password lists and generic token card -based
730 Example request for password and a matching reply:
732 CTRL-REQ-PASSWORD-1:Password needed for SSID foobar
733 > password 1 mysecretpassword
735 Example request for generic token card challenge-response:
737 CTRL-REQ-OTP-2:Challenge 1235663 needed for SSID foobar
743 status = get current WPA/EAPOL/EAP status
744 mib = get MIB variables (dot1x, dot11)
745 help = show this usage help
746 interface [ifname] = show interfaces/select interface
747 level <debug level> = change debug level
748 license = show full wpa_cli license
749 logoff = IEEE 802.1X EAPOL state machine logoff
750 logon = IEEE 802.1X EAPOL state machine logon
751 set = set variables (shows list of variables when run without arguments)
752 pmksa = show PMKSA cache
753 reassociate = force reassociation
754 reconfigure = force wpa_supplicant to re-read its configuration file
755 preauthenticate <BSSID> = force preauthentication
756 identity <network id> <identity> = configure identity for an SSID
757 password <network id> <password> = configure password for an SSID
758 pin <network id> <pin> = configure pin for an SSID
759 otp <network id> <password> = configure one-time-password for an SSID
760 passphrase <network id> <passphrase> = configure private key passphrase
762 bssid <network id> <BSSID> = set preferred BSSID for an SSID
763 list_networks = list configured networks
764 select_network <network id> = select a network (disable others)
765 enable_network <network id> = enable a network
766 disable_network <network id> = disable a network
767 add_network = add a network
768 remove_network <network id> = remove a network
769 set_network <network id> <variable> <value> = set network variables (shows
770 list of variables when run without arguments)
771 get_network <network id> <variable> = get network variables
772 save_config = save the current configuration
773 disconnect = disconnect and wait for reassociate command before connecting
774 scan = request new BSS scan
775 scan_results = get latest scan results
776 get_capability <eap/pairwise/group/key_mgmt/proto/auth_alg> = get capabilies
777 terminate = terminate wpa_supplicant
781 wpa_cli command line options
783 wpa_cli [-p<path to ctrl sockets>] [-i<ifname>] [-hvB] [-a<action file>] \
784 [-P<pid file>] [-g<global ctrl>] [command..]
785 -h = help (show this usage text)
786 -v = shown version information
787 -a = run in daemon mode executing the action file based on events from
789 -B = run a daemon in the background
790 default path: /var/run/wpa_supplicant
791 default interface: first interface found in socket path
794 Using wpa_cli to run external program on connect/disconnect
795 -----------------------------------------------------------
797 wpa_cli can used to run external programs whenever wpa_supplicant
798 connects or disconnects from a network. This can be used, e.g., to
799 update network configuration and/or trigget DHCP client to update IP
802 One wpa_cli process in "action" mode needs to be started for each
803 interface. For example, the following command starts wpa_cli for the
804 default ingterface (-i can be used to select the interface in case of
805 more than one interface being used at the same time):
807 wpa_cli -a/sbin/wpa_action.sh -B
809 The action file (-a option, /sbin/wpa_action.sh in this example) will
810 be executed whenever wpa_supplicant completes authentication (connect
811 event) or detects disconnection). The action script will be called
812 with two command line arguments: interface name and event (CONNECTED
813 or DISCONNECTED). If the action script needs to get more information
814 about the current network, it can use 'wpa_cli status' to query
815 wpa_supplicant for more information.
817 Following example can be used as a simple template for an action
825 if [ "$CMD" = "CONNECTED" ]; then
826 SSID=`wpa_cli -i$IFNAME status | grep ^ssid= | cut -f2- -d=`
827 # configure network, signal DHCP client, etc.
830 if [ "$CMD" = "DISCONNECTED" ]; then
831 # remove network configuration, if needed
837 Integrating with pcmcia-cs/cardmgr scripts
838 ------------------------------------------
840 wpa_supplicant needs to be running when using a wireless network with
841 WPA. It can be started either from system startup scripts or from
842 pcmcia-cs/cardmgr scripts (when using PC Cards). WPA handshake must be
843 completed before data frames can be exchanged, so wpa_supplicant
844 should be started before DHCP client.
846 For example, following small changes to pcmcia-cs scripts can be used
847 to enable WPA support:
849 Add MODE="Managed" and WPA="y" to the network scheme in
850 /etc/pcmcia/wireless.opts.
852 Add the following block to the end of 'start' action handler in
853 /etc/pcmcia/wireless:
855 if [ "$WPA" = "y" -a -x /usr/local/bin/wpa_supplicant ]; then
856 /usr/local/bin/wpa_supplicant -B -c/etc/wpa_supplicant.conf \
860 Add the following block to the end of 'stop' action handler (may need
861 to be separated from other actions) in /etc/pcmcia/wireless:
863 if [ "$WPA" = "y" -a -x /usr/local/bin/wpa_supplicant ]; then
864 killall wpa_supplicant
867 This will make cardmgr start wpa_supplicant when the card is plugged
872 Dynamic interface add and operation without configuration files
873 ---------------------------------------------------------------
875 wpa_supplicant can be started without any configuration files or
876 network interfaces. When used in this way, a global (i.e., per
877 wpa_supplicant process) control interface is used to add and remove
878 network interfaces. Each network interface can then be configured
879 through a per-network interface control interface. For example,
880 following commands show how to start wpa_supplicant without any
881 network interfaces and then add a network interface and configure a
884 # Start wpa_supplicant in the background
885 wpa_supplicant -g/var/run/wpa_supplicant-global -B
887 # Add a new interface (wlan0, no configuration file, driver=wext, and
888 # enable control interface)
889 wpa_cli -g/var/run/wpa_supplicant-global interface_add wlan0 \
890 "" wext /var/run/wpa_supplicant
892 # Configure a network using the newly added network interface:
893 wpa_cli -iwlan0 add_network
894 wpa_cli -iwlan0 set_network 0 ssid '"test"'
895 wpa_cli -iwlan0 set_network 0 key_mgmt WPA-PSK
896 wpa_cli -iwlan0 set_network 0 psk '"12345678"'
897 wpa_cli -iwlan0 set_network 0 pairwise TKIP
898 wpa_cli -iwlan0 set_network 0 group TKIP
899 wpa_cli -iwlan0 set_network 0 proto WPA
900 wpa_cli -iwlan0 enable_network 0
902 # At this point, the new network interface should start trying to associate
903 # with the WPA-PSK network using SSID test.
905 # Remove network interface
906 wpa_cli -g/var/run/wpa_supplicant-global interface_remove wlan0
912 To minimize the size of code that needs to be run with root privileges
913 (e.g., to control wireless interface operation), wpa_supplicant
914 supports optional privilege separation. If enabled, this separates the
915 privileged operations into a separate process (wpa_priv) while leaving
916 rest of the code (e.g., EAP authentication and WPA handshakes) into an
917 unprivileged process (wpa_supplicant) that can be run as non-root
918 user. Privilege separation restricts the effects of potential software
919 errors by containing the majority of the code in an unprivileged
920 process to avoid full system compromise.
922 Privilege separation is not enabled by default and it can be enabled
923 by adding CONFIG_PRIVSEP=y to the build configuration (.config). When
924 enabled, the privileged operations (driver wrapper and l2_packet) are
925 linked into a separate daemon program, wpa_priv. The unprivileged
926 program, wpa_supplicant, will be built with a special driver/l2_packet
927 wrappers that communicate with the privileged wpa_priv process to
928 perform the needed operations. wpa_priv can control what privileged
931 wpa_priv needs to be run with network admin privileges (usually, root
932 user). It opens a UNIX domain socket for each interface that is
933 included on the command line; any other interface will be off limits
934 for wpa_supplicant in this kind of configuration. After this,
935 wpa_supplicant can be run as a non-root user (e.g., all standard users
936 on a laptop or as a special non-privileged user account created just
937 for this purpose to limit access to user files even further).
940 Example configuration:
941 - create user group for users that are allowed to use wpa_supplicant
942 ('wpapriv' in this example) and assign users that should be able to
943 use wpa_supplicant into that group
944 - create /var/run/wpa_priv directory for UNIX domain sockets and control
945 user access by setting it accessible only for the wpapriv group:
946 mkdir /var/run/wpa_priv
947 chown root:wpapriv /var/run/wpa_priv
948 chmod 0750 /var/run/wpa_priv
949 - start wpa_priv as root (e.g., from system startup scripts) with the
950 enabled interfaces configured on the command line:
951 wpa_priv -B -P /var/run/wpa_priv.pid wext:ath0
952 - run wpa_supplicant as non-root with a user that is in wpapriv group:
953 wpa_supplicant -i ath0 -c wpa_supplicant.conf
955 wpa_priv does not use the network interface before wpa_supplicant is
956 started, so it is fine to include network interfaces that are not
957 available at the time wpa_priv is started. As an alternative, wpa_priv
958 can be started when an interface is added (hotplug/udev/etc. scripts).
959 wpa_priv can control multiple interface with one process, but it is
960 also possible to run multiple wpa_priv processes at the same time, if