xref: /freebsd/contrib/wpa/wpa_supplicant/README (revision 13ea0450a9c8742119d36f3bf8f47accdce46e54)
1WPA Supplicant
2==============
3
4Copyright (c) 2003-2018, Jouni Malinen <j@w1.fi> and contributors
5All Rights Reserved.
6
7This program is licensed under the BSD license (the one with
8advertisement clause removed).
9
10If you are submitting changes to the project, please see CONTRIBUTIONS
11file for more instructions.
12
13
14
15License
16-------
17
18This software may be distributed, used, and modified under the terms of
19BSD license:
20
21Redistribution and use in source and binary forms, with or without
22modification, are permitted provided that the following conditions are
23met:
24
251. Redistributions of source code must retain the above copyright
26   notice, this list of conditions and the following disclaimer.
27
282. 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.
31
323. 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.
35
36THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
37"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
38LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
39A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
40OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
41SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
42LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
43DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
44THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
45(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
46OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
47
48
49
50Features
51--------
52
53Supported 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
57  Supplicant:
58  * EAP-TLS
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
65  * EAP-TTLS/EAP-GTC
66  * EAP-TTLS/EAP-OTP
67  * EAP-TTLS/EAP-MSCHAPv2
68  * EAP-TTLS/EAP-TLS
69  * EAP-TTLS/MSCHAPv2
70  * EAP-TTLS/MSCHAP
71  * EAP-TTLS/PAP
72  * EAP-TTLS/CHAP
73  * EAP-SIM
74  * EAP-AKA
75  * EAP-AKA'
76  * EAP-PSK
77  * EAP-PAX
78  * EAP-SAKE
79  * EAP-IKEv2
80  * EAP-GPSK
81  * EAP-pwd
82  * LEAP (note: requires special support from the driver for IEEE 802.11
83	  authentication)
84  (following methods are supported, but since they do not generate keying
85   material, they cannot be used with WPA or IEEE 802.1X WEP keying)
86  * EAP-MD5-Challenge
87  * EAP-MSCHAPv2
88  * EAP-GTC
89  * EAP-OTP
90- key management for CCMP, TKIP, WEP104, WEP40
91- RSN/WPA2 (IEEE 802.11i)
92  * pre-authentication
93  * PMKSA caching
94
95Supported TLS/crypto libraries:
96- OpenSSL (default)
97- GnuTLS
98
99Internal TLS/crypto implementation (optional):
100- can be used in place of an external TLS/crypto library
101- TLSv1
102- X.509 certificate processing
103- PKCS #1
104- ASN.1
105- RSA
106- bignum
107- minimal size (ca. 50 kB binary, parts of which are already needed for WPA;
108  TLSv1/X.509/ASN.1/RSA/bignum parts are about 25 kB on x86)
109
110
111Requirements
112------------
113
114Current hardware/software requirements:
115- Linux kernel 2.4.x or 2.6.x with Linux Wireless Extensions v15 or newer
116- FreeBSD 6-CURRENT
117- NetBSD-current
118- Microsoft Windows with WinPcap (at least WinXP, may work with other versions)
119- drivers:
120	Linux drivers that support cfg80211/nl80211. Even though there are
121	number of driver specific interface included in wpa_supplicant, please
122	note that Linux drivers are moving to use generic wireless configuration
123	interface driver_nl80211 (-Dnl80211 on wpa_supplicant command line)
124	should be the default option to start with before falling back to driver
125	specific interface.
126
127	Linux drivers that support WPA/WPA2 configuration with the generic
128	Linux wireless extensions (WE-18 or newer). Obsoleted by nl80211.
129
130	In theory, any driver that supports Linux wireless extensions can be
131	used with IEEE 802.1X (i.e., not WPA) when using ap_scan=0 option in
132	configuration file.
133
134	Wired Ethernet drivers (with ap_scan=0)
135
136	BSD net80211 layer (e.g., Atheros driver)
137	At the moment, this is for FreeBSD 6-CURRENT branch and NetBSD-current.
138
139	Windows NDIS
140	The current Windows port requires WinPcap (http://winpcap.polito.it/).
141	See README-Windows.txt for more information.
142
143wpa_supplicant was designed to be portable for different drivers and
144operating systems. Hopefully, support for more wlan cards and OSes will be
145added in the future. See developer's documentation
146(http://hostap.epitest.fi/wpa_supplicant/devel/) for more information about the
147design of wpa_supplicant and porting to other drivers. One main goal
148is to add full WPA/WPA2 support to Linux wireless extensions to allow
149new drivers to be supported without having to implement new
150driver-specific interface code in wpa_supplicant.
151
152Optional libraries for layer2 packet processing:
153- libpcap (tested with 0.7.2, most relatively recent versions assumed to work,
154	this is likely to be available with most distributions,
155	http://tcpdump.org/)
156- libdnet (tested with v1.4, most versions assumed to work,
157	http://libdnet.sourceforge.net/)
158
159These libraries are _not_ used in the default Linux build. Instead,
160internal Linux specific implementation is used. libpcap/libdnet are
161more portable and they can be used by adding CONFIG_L2_PACKET=pcap into
162.config. They may also be selected automatically for other operating
163systems. In case of Windows builds, WinPcap is used by default
164(CONFIG_L2_PACKET=winpcap).
165
166
167Optional libraries for EAP-TLS, EAP-PEAP, and EAP-TTLS:
168- OpenSSL (tested with 1.0.1 and 1.0.2 versions; assumed to
169  work with most relatively recent versions; this is likely to be
170  available with most distributions, http://www.openssl.org/)
171- GnuTLS
172- internal TLSv1 implementation
173
174One of these libraries is needed when EAP-TLS, EAP-PEAP, EAP-TTLS, or
175EAP-FAST support is enabled. WPA-PSK mode does not require this or EAPOL/EAP
176implementation. A configuration file, .config, for compilation is
177needed to enable IEEE 802.1X/EAPOL and EAP methods. Note that EAP-MD5,
178EAP-GTC, EAP-OTP, and EAP-MSCHAPV2 cannot be used alone with WPA, so
179they should only be enabled if testing the EAPOL/EAP state
180machines. However, there can be used as inner authentication
181algorithms with EAP-PEAP and EAP-TTLS.
182
183See Building and installing section below for more detailed
184information about the wpa_supplicant build time configuration.
185
186
187
188WPA
189---
190
191The original security mechanism of IEEE 802.11 standard was not
192designed to be strong and has proven to be insufficient for most
193networks that require some kind of security. Task group I (Security)
194of IEEE 802.11 working group (http://www.ieee802.org/11/) has worked
195to address the flaws of the base standard and has in practice
196completed its work in May 2004. The IEEE 802.11i amendment to the IEEE
197802.11 standard was approved in June 2004 and published in July 2004.
198
199Wi-Fi Alliance (http://www.wi-fi.org/) used a draft version of the
200IEEE 802.11i work (draft 3.0) to define a subset of the security
201enhancements that can be implemented with existing wlan hardware. This
202is called Wi-Fi Protected Access<TM> (WPA). This has now become a
203mandatory component of interoperability testing and certification done
204by Wi-Fi Alliance. Wi-Fi provides information about WPA at its web
205site (http://www.wi-fi.org/OpenSection/protected_access.asp).
206
207IEEE 802.11 standard defined wired equivalent privacy (WEP) algorithm
208for protecting wireless networks. WEP uses RC4 with 40-bit keys,
20924-bit initialization vector (IV), and CRC32 to protect against packet
210forgery. All these choices have proven to be insufficient: key space is
211too small against current attacks, RC4 key scheduling is insufficient
212(beginning of the pseudorandom stream should be skipped), IV space is
213too small and IV reuse makes attacks easier, there is no replay
214protection, and non-keyed authentication does not protect against bit
215flipping packet data.
216
217WPA is an intermediate solution for the security issues. It uses
218Temporal Key Integrity Protocol (TKIP) to replace WEP. TKIP is a
219compromise on strong security and possibility to use existing
220hardware. It still uses RC4 for the encryption like WEP, but with
221per-packet RC4 keys. In addition, it implements replay protection,
222keyed packet authentication mechanism (Michael MIC).
223
224Keys can be managed using two different mechanisms. WPA can either use
225an external authentication server (e.g., RADIUS) and EAP just like
226IEEE 802.1X is using or pre-shared keys without need for additional
227servers. Wi-Fi calls these "WPA-Enterprise" and "WPA-Personal",
228respectively. Both mechanisms will generate a master session key for
229the Authenticator (AP) and Supplicant (client station).
230
231WPA implements a new key handshake (4-Way Handshake and Group Key
232Handshake) for generating and exchanging data encryption keys between
233the Authenticator and Supplicant. This handshake is also used to
234verify that both Authenticator and Supplicant know the master session
235key. These handshakes are identical regardless of the selected key
236management mechanism (only the method for generating master session
237key changes).
238
239
240
241IEEE 802.11i / WPA2
242-------------------
243
244The design for parts of IEEE 802.11i that were not included in WPA has
245finished (May 2004) and this amendment to IEEE 802.11 was approved in
246June 2004. Wi-Fi Alliance is using the final IEEE 802.11i as a new
247version of WPA called WPA2. This includes, e.g., support for more
248robust encryption algorithm (CCMP: AES in Counter mode with CBC-MAC)
249to replace TKIP and optimizations for handoff (reduced number of
250messages in initial key handshake, pre-authentication, and PMKSA caching).
251
252
253
254wpa_supplicant
255--------------
256
257wpa_supplicant is an implementation of the WPA Supplicant component,
258i.e., the part that runs in the client stations. It implements WPA key
259negotiation with a WPA Authenticator and EAP authentication with
260Authentication Server. In addition, it controls the roaming and IEEE
261802.11 authentication/association of the wlan driver.
262
263wpa_supplicant is designed to be a "daemon" program that runs in the
264background and acts as the backend component controlling the wireless
265connection. wpa_supplicant supports separate frontend programs and an
266example text-based frontend, wpa_cli, is included with wpa_supplicant.
267
268Following steps are used when associating with an AP using WPA:
269
270- wpa_supplicant requests the kernel driver to scan neighboring BSSes
271- wpa_supplicant selects a BSS based on its configuration
272- wpa_supplicant requests the kernel driver to associate with the chosen
273  BSS
274- If WPA-EAP: integrated IEEE 802.1X Supplicant completes EAP
275  authentication with the authentication server (proxied by the
276  Authenticator in the AP)
277- If WPA-EAP: master key is received from the IEEE 802.1X Supplicant
278- If WPA-PSK: wpa_supplicant uses PSK as the master session key
279- wpa_supplicant completes WPA 4-Way Handshake and Group Key Handshake
280  with the Authenticator (AP)
281- wpa_supplicant configures encryption keys for unicast and broadcast
282- normal data packets can be transmitted and received
283
284
285
286Building and installing
287-----------------------
288
289In order to be able to build wpa_supplicant, you will first need to
290select which parts of it will be included. This is done by creating a
291build time configuration file, .config, in the wpa_supplicant root
292directory. Configuration options are text lines using following
293format: CONFIG_<option>=y. Lines starting with # are considered
294comments and are ignored. See defconfig file for an example configuration
295and a list of available options and additional notes.
296
297The build time configuration can be used to select only the needed
298features and limit the binary size and requirements for external
299libraries. The main configuration parts are the selection of which
300driver interfaces (e.g., nl80211, wext, ..) and which authentication
301methods (e.g., EAP-TLS, EAP-PEAP, ..) are included.
302
303Following build time configuration options are used to control IEEE
304802.1X/EAPOL and EAP state machines and all EAP methods. Including
305TLS, PEAP, or TTLS will require linking wpa_supplicant with OpenSSL
306library for TLS implementation. Alternatively, GnuTLS or the internal
307TLSv1 implementation can be used for TLS functionality.
308
309CONFIG_IEEE8021X_EAPOL=y
310CONFIG_EAP_MD5=y
311CONFIG_EAP_MSCHAPV2=y
312CONFIG_EAP_TLS=y
313CONFIG_EAP_PEAP=y
314CONFIG_EAP_TTLS=y
315CONFIG_EAP_GTC=y
316CONFIG_EAP_OTP=y
317CONFIG_EAP_SIM=y
318CONFIG_EAP_AKA=y
319CONFIG_EAP_AKA_PRIME=y
320CONFIG_EAP_PSK=y
321CONFIG_EAP_SAKE=y
322CONFIG_EAP_GPSK=y
323CONFIG_EAP_PAX=y
324CONFIG_EAP_LEAP=y
325CONFIG_EAP_IKEV2=y
326CONFIG_EAP_PWD=y
327
328Following option can be used to include GSM SIM/USIM interface for GSM/UMTS
329authentication algorithm (for EAP-SIM/EAP-AKA/EAP-AKA'). This requires pcsc-lite
330(http://www.linuxnet.com/) for smart card access.
331
332CONFIG_PCSC=y
333
334Following options can be added to .config to select which driver
335interfaces are included.
336
337CONFIG_DRIVER_NL80211=y
338CONFIG_DRIVER_WEXT=y
339CONFIG_DRIVER_BSD=y
340CONFIG_DRIVER_NDIS=y
341
342Following example includes some more features and driver interfaces that
343are included in the wpa_supplicant package:
344
345CONFIG_DRIVER_NL80211=y
346CONFIG_DRIVER_WEXT=y
347CONFIG_DRIVER_BSD=y
348CONFIG_DRIVER_NDIS=y
349CONFIG_IEEE8021X_EAPOL=y
350CONFIG_EAP_MD5=y
351CONFIG_EAP_MSCHAPV2=y
352CONFIG_EAP_TLS=y
353CONFIG_EAP_PEAP=y
354CONFIG_EAP_TTLS=y
355CONFIG_EAP_GTC=y
356CONFIG_EAP_OTP=y
357CONFIG_EAP_SIM=y
358CONFIG_EAP_AKA=y
359CONFIG_EAP_PSK=y
360CONFIG_EAP_SAKE=y
361CONFIG_EAP_GPSK=y
362CONFIG_EAP_PAX=y
363CONFIG_EAP_LEAP=y
364CONFIG_EAP_IKEV2=y
365CONFIG_PCSC=y
366
367EAP-PEAP and EAP-TTLS will automatically include configured EAP
368methods (MD5, OTP, GTC, MSCHAPV2) for inner authentication selection.
369
370
371After you have created a configuration file, you can build
372wpa_supplicant and wpa_cli with 'make' command. You may then install
373the binaries to a suitable system directory, e.g., /usr/local/bin.
374
375Example commands:
376
377# build wpa_supplicant and wpa_cli
378make
379# install binaries (this may need root privileges)
380cp wpa_cli wpa_supplicant /usr/local/bin
381
382
383You will need to make a configuration file, e.g.,
384/etc/wpa_supplicant.conf, with network configuration for the networks
385you are going to use. Configuration file section below includes
386explanation fo the configuration file format and includes various
387examples. Once the configuration is ready, you can test whether the
388configuration work by first running wpa_supplicant with following
389command to start it on foreground with debugging enabled:
390
391wpa_supplicant -iwlan0 -c/etc/wpa_supplicant.conf -d
392
393Assuming everything goes fine, you can start using following command
394to start wpa_supplicant on background without debugging:
395
396wpa_supplicant -iwlan0 -c/etc/wpa_supplicant.conf -B
397
398Please note that if you included more than one driver interface in the
399build time configuration (.config), you may need to specify which
400interface to use by including -D<driver name> option on the command
401line. See following section for more details on command line options
402for wpa_supplicant.
403
404
405
406Command line options
407--------------------
408
409usage:
410  wpa_supplicant [-BddfhKLqqtuvW] [-P<pid file>] [-g<global ctrl>] \
411        [-G<group>] \
412        -i<ifname> -c<config file> [-C<ctrl>] [-D<driver>] [-p<driver_param>] \
413        [-b<br_ifname> [-MN -i<ifname> -c<conf> [-C<ctrl>] [-D<driver>] \
414        [-p<driver_param>] [-b<br_ifname>] [-m<P2P Device config file>] ...
415
416options:
417  -b = optional bridge interface name
418  -B = run daemon in the background
419  -c = Configuration file
420  -C = ctrl_interface parameter (only used if -c is not)
421  -i = interface name
422  -d = increase debugging verbosity (-dd even more)
423  -D = driver name (can be multiple drivers: nl80211,wext)
424  -f = Log output to default log location (normally /tmp)
425  -g = global ctrl_interface
426  -G = global ctrl_interface group
427  -K = include keys (passwords, etc.) in debug output
428  -t = include timestamp in debug messages
429  -h = show this help text
430  -L = show license (BSD)
431  -p = driver parameters
432  -P = PID file
433  -q = decrease debugging verbosity (-qq even less)
434  -u = enable DBus control interface
435  -v = show version
436  -W = wait for a control interface monitor before starting
437  -M = start describing matching interface
438  -N = start describing new interface
439  -m = Configuration file for the P2P Device
440
441drivers:
442  nl80211 = Linux nl80211/cfg80211
443  wext = Linux wireless extensions (generic)
444  wired = wpa_supplicant wired Ethernet driver
445  roboswitch = wpa_supplicant Broadcom switch driver
446  bsd = BSD 802.11 support (Atheros, etc.)
447  ndis = Windows NDIS driver
448
449In most common cases, wpa_supplicant is started with
450
451wpa_supplicant -B -c/etc/wpa_supplicant.conf -iwlan0
452
453This makes the process fork into background.
454
455The easiest way to debug problems, and to get debug log for bug
456reports, is to start wpa_supplicant on foreground with debugging
457enabled:
458
459wpa_supplicant -c/etc/wpa_supplicant.conf -iwlan0 -d
460
461If the specific driver wrapper is not known beforehand, it is possible
462to specify multiple comma separated driver wrappers on the command
463line. wpa_supplicant will use the first driver wrapper that is able to
464initialize the interface.
465
466wpa_supplicant -Dnl80211,wext -c/etc/wpa_supplicant.conf -iwlan0
467
468
469wpa_supplicant can control multiple interfaces (radios) either by
470running one process for each interface separately or by running just
471one process and list of options at command line. Each interface is
472separated with -N argument. As an example, following command would
473start wpa_supplicant for two interfaces:
474
475wpa_supplicant \
476	-c wpa1.conf -i wlan0 -D nl80211 -N \
477	-c wpa2.conf -i wlan1 -D wext
478
479
480If the interfaces on which wpa_supplicant is to run are not known or do
481not exist, wpa_supplicant can match an interface when it arrives. Each
482matched interface is separated with -M argument and the -i argument now
483allows for pattern matching.
484
485As an example, the following command would start wpa_supplicant for a
486specific wired interface called lan0, any interface starting with wlan
487and lastly any other interface. Each match has its own configuration
488file, and for the wired interface a specific driver has also been given.
489
490wpa_supplicant \
491	-M -c wpa_wired.conf -ilan0 -D wired \
492	-M -c wpa1.conf -iwlan* \
493	-M -c wpa2.conf
494
495
496If the interface is added in a Linux bridge (e.g., br0), the bridge
497interface needs to be configured to wpa_supplicant in addition to the
498main interface:
499
500wpa_supplicant -cw.conf -Dnl80211 -iwlan0 -bbr0
501
502
503Configuration file
504------------------
505
506wpa_supplicant is configured using a text file that lists all accepted
507networks and security policies, including pre-shared keys. See
508example configuration file, wpa_supplicant.conf, for detailed
509information about the configuration format and supported fields.
510
511Changes to configuration file can be reloaded be sending SIGHUP signal
512to wpa_supplicant ('killall -HUP wpa_supplicant'). Similarly,
513reloading can be triggered with 'wpa_cli reconfigure' command.
514
515Configuration file can include one or more network blocks, e.g., one
516for each used SSID. wpa_supplicant will automatically select the best
517network based on the order of network blocks in the configuration
518file, network security level (WPA/WPA2 is preferred), and signal
519strength.
520
521Example configuration files for some common configurations:
522
5231) WPA-Personal (PSK) as home network and WPA-Enterprise with EAP-TLS as work
524   network
525
526# allow frontend (e.g., wpa_cli) to be used by all users in 'wheel' group
527ctrl_interface=/var/run/wpa_supplicant
528ctrl_interface_group=wheel
529#
530# home network; allow all valid ciphers
531network={
532	ssid="home"
533	scan_ssid=1
534	key_mgmt=WPA-PSK
535	psk="very secret passphrase"
536}
537#
538# work network; use EAP-TLS with WPA; allow only CCMP and TKIP ciphers
539network={
540	ssid="work"
541	scan_ssid=1
542	key_mgmt=WPA-EAP
543	pairwise=CCMP TKIP
544	group=CCMP TKIP
545	eap=TLS
546	identity="user@example.com"
547	ca_cert="/etc/cert/ca.pem"
548	client_cert="/etc/cert/user.pem"
549	private_key="/etc/cert/user.prv"
550	private_key_passwd="password"
551}
552
553
5542) WPA-RADIUS/EAP-PEAP/MSCHAPv2 with RADIUS servers that use old peaplabel
555   (e.g., Funk Odyssey and SBR, Meetinghouse Aegis, Interlink RAD-Series)
556
557ctrl_interface=/var/run/wpa_supplicant
558ctrl_interface_group=wheel
559network={
560	ssid="example"
561	scan_ssid=1
562	key_mgmt=WPA-EAP
563	eap=PEAP
564	identity="user@example.com"
565	password="foobar"
566	ca_cert="/etc/cert/ca.pem"
567	phase1="peaplabel=0"
568	phase2="auth=MSCHAPV2"
569}
570
571
5723) EAP-TTLS/EAP-MD5-Challenge configuration with anonymous identity for the
573   unencrypted use. Real identity is sent only within an encrypted TLS tunnel.
574
575ctrl_interface=/var/run/wpa_supplicant
576ctrl_interface_group=wheel
577network={
578	ssid="example"
579	scan_ssid=1
580	key_mgmt=WPA-EAP
581	eap=TTLS
582	identity="user@example.com"
583	anonymous_identity="anonymous@example.com"
584	password="foobar"
585	ca_cert="/etc/cert/ca.pem"
586	phase2="auth=MD5"
587}
588
589
5904) IEEE 802.1X (i.e., no WPA) with dynamic WEP keys (require both unicast and
591   broadcast); use EAP-TLS for authentication
592
593ctrl_interface=/var/run/wpa_supplicant
594ctrl_interface_group=wheel
595network={
596	ssid="1x-test"
597	scan_ssid=1
598	key_mgmt=IEEE8021X
599	eap=TLS
600	identity="user@example.com"
601	ca_cert="/etc/cert/ca.pem"
602	client_cert="/etc/cert/user.pem"
603	private_key="/etc/cert/user.prv"
604	private_key_passwd="password"
605	eapol_flags=3
606}
607
608
6095) Catch all example that allows more or less all configuration modes. The
610   configuration options are used based on what security policy is used in the
611   selected SSID. This is mostly for testing and is not recommended for normal
612   use.
613
614ctrl_interface=/var/run/wpa_supplicant
615ctrl_interface_group=wheel
616network={
617	ssid="example"
618	scan_ssid=1
619	key_mgmt=WPA-EAP WPA-PSK IEEE8021X NONE
620	pairwise=CCMP TKIP
621	group=CCMP TKIP WEP104 WEP40
622	psk="very secret passphrase"
623	eap=TTLS PEAP TLS
624	identity="user@example.com"
625	password="foobar"
626	ca_cert="/etc/cert/ca.pem"
627	client_cert="/etc/cert/user.pem"
628	private_key="/etc/cert/user.prv"
629	private_key_passwd="password"
630	phase1="peaplabel=0"
631	ca_cert2="/etc/cert/ca2.pem"
632	client_cert2="/etc/cer/user.pem"
633	private_key2="/etc/cer/user.prv"
634	private_key2_passwd="password"
635}
636
637
6386) Authentication for wired Ethernet. This can be used with 'wired' or
639   'roboswitch' interface (-Dwired or -Droboswitch on command line).
640
641ctrl_interface=/var/run/wpa_supplicant
642ctrl_interface_group=wheel
643ap_scan=0
644network={
645	key_mgmt=IEEE8021X
646	eap=MD5
647	identity="user"
648	password="password"
649	eapol_flags=0
650}
651
652
653
654Certificates
655------------
656
657Some EAP authentication methods require use of certificates. EAP-TLS
658uses both server side and client certificates whereas EAP-PEAP and
659EAP-TTLS only require the server side certificate. When client
660certificate is used, a matching private key file has to also be
661included in configuration. If the private key uses a passphrase, this
662has to be configured in wpa_supplicant.conf ("private_key_passwd").
663
664wpa_supplicant supports X.509 certificates in PEM and DER
665formats. User certificate and private key can be included in the same
666file.
667
668If the user certificate and private key is received in PKCS#12/PFX
669format, they need to be converted to suitable PEM/DER format for
670wpa_supplicant. This can be done, e.g., with following commands:
671
672# convert client certificate and private key to PEM format
673openssl pkcs12 -in example.pfx -out user.pem -clcerts
674# convert CA certificate (if included in PFX file) to PEM format
675openssl pkcs12 -in example.pfx -out ca.pem -cacerts -nokeys
676
677
678
679wpa_cli
680-------
681
682wpa_cli is a text-based frontend program for interacting with
683wpa_supplicant. It is used to query current status, change
684configuration, trigger events, and request interactive user input.
685
686wpa_cli can show the current authentication status, selected security
687mode, dot11 and dot1x MIBs, etc. In addition, it can configure some
688variables like EAPOL state machine parameters and trigger events like
689reassociation and IEEE 802.1X logoff/logon. wpa_cli provides a user
690interface to request authentication information, like username and
691password, if these are not included in the configuration. This can be
692used to implement, e.g., one-time-passwords or generic token card
693authentication where the authentication is based on a
694challenge-response that uses an external device for generating the
695response.
696
697The control interface of wpa_supplicant can be configured to allow
698non-root user access (ctrl_interface_group in the configuration
699file). This makes it possible to run wpa_cli with a normal user
700account.
701
702wpa_cli supports two modes: interactive and command line. Both modes
703share the same command set and the main difference is in interactive
704mode providing access to unsolicited messages (event messages,
705username/password requests).
706
707Interactive mode is started when wpa_cli is executed without including
708the command as a command line parameter. Commands are then entered on
709the wpa_cli prompt. In command line mode, the same commands are
710entered as command line arguments for wpa_cli.
711
712
713Interactive authentication parameters request
714
715When wpa_supplicant need authentication parameters, like username and
716password, which are not present in the configuration file, it sends a
717request message to all attached frontend programs, e.g., wpa_cli in
718interactive mode. wpa_cli shows these requests with
719"CTRL-REQ-<type>-<id>:<text>" prefix. <type> is IDENTITY, PASSWORD, or
720OTP (one-time-password). <id> is a unique identifier for the current
721network. <text> is description of the request. In case of OTP request,
722it includes the challenge from the authentication server.
723
724The reply to these requests can be given with 'identity', 'password',
725and 'otp' commands. <id> needs to be copied from the the matching
726request. 'password' and 'otp' commands can be used regardless of
727whether the request was for PASSWORD or OTP. The main difference
728between these two commands is that values given with 'password' are
729remembered as long as wpa_supplicant is running whereas values given
730with 'otp' are used only once and then forgotten, i.e., wpa_supplicant
731will ask frontend for a new value for every use. This can be used to
732implement one-time-password lists and generic token card -based
733authentication.
734
735Example request for password and a matching reply:
736
737CTRL-REQ-PASSWORD-1:Password needed for SSID foobar
738> password 1 mysecretpassword
739
740Example request for generic token card challenge-response:
741
742CTRL-REQ-OTP-2:Challenge 1235663 needed for SSID foobar
743> otp 2 9876
744
745
746wpa_cli commands
747
748  status = get current WPA/EAPOL/EAP status
749  mib = get MIB variables (dot1x, dot11)
750  help = show this usage help
751  interface [ifname] = show interfaces/select interface
752  level <debug level> = change debug level
753  license = show full wpa_cli license
754  logoff = IEEE 802.1X EAPOL state machine logoff
755  logon = IEEE 802.1X EAPOL state machine logon
756  set = set variables (shows list of variables when run without arguments)
757  pmksa = show PMKSA cache
758  reassociate = force reassociation
759  reconfigure = force wpa_supplicant to re-read its configuration file
760  preauthenticate <BSSID> = force preauthentication
761  identity <network id> <identity> = configure identity for an SSID
762  password <network id> <password> = configure password for an SSID
763  pin <network id> <pin> = configure pin for an SSID
764  otp <network id> <password> = configure one-time-password for an SSID
765  passphrase <network id> <passphrase> = configure private key passphrase
766    for an SSID
767  bssid <network id> <BSSID> = set preferred BSSID for an SSID
768  list_networks = list configured networks
769  select_network <network id> = select a network (disable others)
770  enable_network <network id> = enable a network
771  disable_network <network id> = disable a network
772  add_network = add a network
773  remove_network <network id> = remove a network
774  set_network <network id> <variable> <value> = set network variables (shows
775    list of variables when run without arguments)
776  get_network <network id> <variable> = get network variables
777  save_config = save the current configuration
778  disconnect = disconnect and wait for reassociate command before connecting
779  scan = request new BSS scan
780  scan_results = get latest scan results
781  get_capability <eap/pairwise/group/key_mgmt/proto/auth_alg> = get capabilies
782  terminate = terminate wpa_supplicant
783  quit = exit wpa_cli
784
785
786wpa_cli command line options
787
788wpa_cli [-p<path to ctrl sockets>] [-i<ifname>] [-hvB] [-a<action file>] \
789        [-P<pid file>] [-g<global ctrl>]  [command..]
790  -h = help (show this usage text)
791  -v = shown version information
792  -a = run in daemon mode executing the action file based on events from
793       wpa_supplicant
794  -B = run a daemon in the background
795  default path: /var/run/wpa_supplicant
796  default interface: first interface found in socket path
797
798
799Using wpa_cli to run external program on connect/disconnect
800-----------------------------------------------------------
801
802wpa_cli can used to run external programs whenever wpa_supplicant
803connects or disconnects from a network. This can be used, e.g., to
804update network configuration and/or trigget DHCP client to update IP
805addresses, etc.
806
807One wpa_cli process in "action" mode needs to be started for each
808interface. For example, the following command starts wpa_cli for the
809default interface (-i can be used to select the interface in case of
810more than one interface being used at the same time):
811
812wpa_cli -a/sbin/wpa_action.sh -B
813
814The action file (-a option, /sbin/wpa_action.sh in this example) will
815be executed whenever wpa_supplicant completes authentication (connect
816event) or detects disconnection). The action script will be called
817with two command line arguments: interface name and event (CONNECTED
818or DISCONNECTED). If the action script needs to get more information
819about the current network, it can use 'wpa_cli status' to query
820wpa_supplicant for more information.
821
822Following example can be used as a simple template for an action
823script:
824
825#!/bin/sh
826
827IFNAME=$1
828CMD=$2
829
830if [ "$CMD" = "CONNECTED" ]; then
831    SSID=`wpa_cli -i$IFNAME status | grep ^ssid= | cut -f2- -d=`
832    # configure network, signal DHCP client, etc.
833fi
834
835if [ "$CMD" = "DISCONNECTED" ]; then
836    # remove network configuration, if needed
837    SSID=
838fi
839
840
841
842Integrating with pcmcia-cs/cardmgr scripts
843------------------------------------------
844
845wpa_supplicant needs to be running when using a wireless network with
846WPA. It can be started either from system startup scripts or from
847pcmcia-cs/cardmgr scripts (when using PC Cards). WPA handshake must be
848completed before data frames can be exchanged, so wpa_supplicant
849should be started before DHCP client.
850
851For example, following small changes to pcmcia-cs scripts can be used
852to enable WPA support:
853
854Add MODE="Managed" and WPA="y" to the network scheme in
855/etc/pcmcia/wireless.opts.
856
857Add the following block to the end of 'start' action handler in
858/etc/pcmcia/wireless:
859
860    if [ "$WPA" = "y" -a -x /usr/local/bin/wpa_supplicant ]; then
861	/usr/local/bin/wpa_supplicant -B -c/etc/wpa_supplicant.conf \
862		-i$DEVICE
863    fi
864
865Add the following block to the end of 'stop' action handler (may need
866to be separated from other actions) in /etc/pcmcia/wireless:
867
868    if [ "$WPA" = "y" -a -x /usr/local/bin/wpa_supplicant ]; then
869	killall wpa_supplicant
870    fi
871
872This will make cardmgr start wpa_supplicant when the card is plugged
873in.
874
875
876
877Dynamic interface add and operation without configuration files
878---------------------------------------------------------------
879
880wpa_supplicant can be started without any configuration files or
881network interfaces. When used in this way, a global (i.e., per
882wpa_supplicant process) control interface is used to add and remove
883network interfaces. Each network interface can then be configured
884through a per-network interface control interface. For example,
885following commands show how to start wpa_supplicant without any
886network interfaces and then add a network interface and configure a
887network (SSID):
888
889# Start wpa_supplicant in the background
890wpa_supplicant -g/var/run/wpa_supplicant-global -B
891
892# Add a new interface (wlan0, no configuration file, driver=nl80211, and
893# enable control interface)
894wpa_cli -g/var/run/wpa_supplicant-global interface_add wlan0 \
895	"" nl80211 /var/run/wpa_supplicant
896
897# Configure a network using the newly added network interface:
898wpa_cli -iwlan0 add_network
899wpa_cli -iwlan0 set_network 0 ssid '"test"'
900wpa_cli -iwlan0 set_network 0 key_mgmt WPA-PSK
901wpa_cli -iwlan0 set_network 0 psk '"12345678"'
902wpa_cli -iwlan0 set_network 0 pairwise TKIP
903wpa_cli -iwlan0 set_network 0 group TKIP
904wpa_cli -iwlan0 set_network 0 proto WPA
905wpa_cli -iwlan0 enable_network 0
906
907# At this point, the new network interface should start trying to associate
908# with the WPA-PSK network using SSID test.
909
910# Remove network interface
911wpa_cli -g/var/run/wpa_supplicant-global interface_remove wlan0
912
913
914Privilege separation
915--------------------
916
917To minimize the size of code that needs to be run with root privileges
918(e.g., to control wireless interface operation), wpa_supplicant
919supports optional privilege separation. If enabled, this separates the
920privileged operations into a separate process (wpa_priv) while leaving
921rest of the code (e.g., EAP authentication and WPA handshakes) into an
922unprivileged process (wpa_supplicant) that can be run as non-root
923user. Privilege separation restricts the effects of potential software
924errors by containing the majority of the code in an unprivileged
925process to avoid full system compromise.
926
927Privilege separation is not enabled by default and it can be enabled
928by adding CONFIG_PRIVSEP=y to the build configuration (.config). When
929enabled, the privileged operations (driver wrapper and l2_packet) are
930linked into a separate daemon program, wpa_priv. The unprivileged
931program, wpa_supplicant, will be built with a special driver/l2_packet
932wrappers that communicate with the privileged wpa_priv process to
933perform the needed operations. wpa_priv can control what privileged
934are allowed.
935
936wpa_priv needs to be run with network admin privileges (usually, root
937user). It opens a UNIX domain socket for each interface that is
938included on the command line; any other interface will be off limits
939for wpa_supplicant in this kind of configuration. After this,
940wpa_supplicant can be run as a non-root user (e.g., all standard users
941on a laptop or as a special non-privileged user account created just
942for this purpose to limit access to user files even further).
943
944
945Example configuration:
946- create user group for users that are allowed to use wpa_supplicant
947  ('wpapriv' in this example) and assign users that should be able to
948  use wpa_supplicant into that group
949- create /var/run/wpa_priv directory for UNIX domain sockets and control
950  user access by setting it accessible only for the wpapriv group:
951  mkdir /var/run/wpa_priv
952  chown root:wpapriv /var/run/wpa_priv
953  chmod 0750 /var/run/wpa_priv
954- start wpa_priv as root (e.g., from system startup scripts) with the
955  enabled interfaces configured on the command line:
956  wpa_priv -B -P /var/run/wpa_priv.pid nl80211:wlan0
957- run wpa_supplicant as non-root with a user that is in wpapriv group:
958  wpa_supplicant -i ath0 -c wpa_supplicant.conf
959
960wpa_priv does not use the network interface before wpa_supplicant is
961started, so it is fine to include network interfaces that are not
962available at the time wpa_priv is started. As an alternative, wpa_priv
963can be started when an interface is added (hotplug/udev/etc. scripts).
964wpa_priv can control multiple interface with one process, but it is
965also possible to run multiple wpa_priv processes at the same time, if
966desired.
967
968It should be noted that the interface used between wpa_supplicant and
969wpa_priv does not include all the capabilities of the wpa_supplicant
970driver interface and at times, this interface lacks update especially
971for recent addition. Consequently, use of wpa_priv does come with the
972price of somewhat reduced available functionality. The next section
973describing how wpa_supplicant can be used with reduced privileges
974without having to handle the complexity of separate wpa_priv. While that
975approve does not provide separation for network admin capabilities, it
976does allow other root privileges to be dropped without the drawbacks of
977the wpa_priv process.
978
979
980Linux capabilities instead of privileged process
981------------------------------------------------
982
983wpa_supplicant performs operations that need special permissions, e.g.,
984to control the network connection. Traditionally this has been achieved
985by running wpa_supplicant as a privileged process with effective user id
9860 (root). Linux capabilities can be used to provide restricted set of
987capabilities to match the functions needed by wpa_supplicant. The
988minimum set of capabilities needed for the operations is CAP_NET_ADMIN
989and CAP_NET_RAW.
990
991setcap(8) can be used to set file capabilities. For example:
992
993sudo setcap cap_net_raw,cap_net_admin+ep wpa_supplicant
994
995Please note that this would give anyone being able to run that
996wpa_supplicant binary access to the additional capabilities. This can
997further be limited by file owner/group and mode bits. For example:
998
999sudo chown wpas wpa_supplicant
1000sudo chmod 0100 wpa_supplicant
1001
1002This combination of setcap, chown, and chmod commands would allow wpas
1003user to execute wpa_supplicant with additional network admin/raw
1004capabilities.
1005
1006Common way style of creating a control interface socket in
1007/var/run/wpa_supplicant could not be done by this user, but this
1008directory could be created before starting the wpa_supplicant and set to
1009suitable mode to allow wpa_supplicant to create sockets
1010there. Alternatively, other directory or abstract socket namespace could
1011be used for the control interface.
1012
1013
1014External requests for radio control
1015-----------------------------------
1016
1017External programs can request wpa_supplicant to not start offchannel
1018operations during other tasks that may need exclusive control of the
1019radio. The RADIO_WORK control interface command can be used for this.
1020
1021"RADIO_WORK add <name> [freq=<MHz>] [timeout=<seconds>]" command can be
1022used to reserve a slot for radio access. If freq is specified, other
1023radio work items on the same channel may be completed in
1024parallel. Otherwise, all other radio work items are blocked during
1025execution. Timeout is set to 10 seconds by default to avoid blocking
1026wpa_supplicant operations for excessive time. If a longer (or shorter)
1027safety timeout is needed, that can be specified with the optional
1028timeout parameter. This command returns an identifier for the radio work
1029item.
1030
1031Once the radio work item has been started, "EXT-RADIO-WORK-START <id>"
1032event message is indicated that the external processing can start. Once
1033the operation has been completed, "RADIO_WORK done <id>" is used to
1034indicate that to wpa_supplicant. This allows other radio works to be
1035performed. If this command is forgotten (e.g., due to the external
1036program terminating), wpa_supplicant will time out the radio work item
1037and send "EXT-RADIO-WORK-TIMEOUT <id>" event to indicate that this has
1038happened. "RADIO_WORK done <id>" can also be used to cancel items that
1039have not yet been started.
1040
1041For example, in wpa_cli interactive mode:
1042
1043> radio_work add test
10441
1045<3>EXT-RADIO-WORK-START 1
1046> radio_work show
1047ext:test@wlan0:0:1:2.487797
1048> radio_work done 1
1049OK
1050> radio_work show
1051
1052
1053> radio_work done 3
1054OK
1055> radio_work show
1056ext:test freq=2412 timeout=30@wlan0:2412:1:28.583483
1057<3>EXT-RADIO-WORK-TIMEOUT 2
1058
1059
1060> radio_work add test2 freq=2412 timeout=60
10615
1062<3>EXT-RADIO-WORK-START 5
1063> radio_work add test3
10646
1065> radio_work add test4
10667
1067> radio_work show
1068ext:test2 freq=2412 timeout=60@wlan0:2412:1:9.751844
1069ext:test3@wlan0:0:0:5.071812
1070ext:test4@wlan0:0:0:3.143870
1071> radio_work done 6
1072OK
1073> radio_work show
1074ext:test2 freq=2412 timeout=60@wlan0:2412:1:16.287869
1075ext:test4@wlan0:0:0:9.679895
1076> radio_work done 5
1077OK
1078<3>EXT-RADIO-WORK-START 7
1079<3>EXT-RADIO-WORK-TIMEOUT 7
1080