wpa_supplicant/README

   1 WPA Supplicant
   2 ==============
   3
   4 Copyright (c) 2003-2013, Jouni Malinen <j@w1.fi> and contributors
   5 All Rights Reserved.
   6
   7 This program is licensed under the BSD license (the one with
   8 advertisement clause removed).
   9
  10 If you are submitting changes to the project, please see CONTRIBUTIONS
  11 file for more instructions.
  12
  13
  14
  15 License
  16 -------
  17
  18 This software may be distributed, used, and modified under the terms of
  19 BSD license:
  20
  21 Redistribution and use in source and binary forms, with or without
  22 modification, are permitted provided that the following conditions are
  23 met:
  24
  25 1. Redistributions of source code must retain the above copyright
  26    notice, this list of conditions and the following disclaimer.
  27
  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.
  31
  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.
  35
  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.
  47
  48
  49
  50 Features
  51 --------
  52
  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
  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-PSK
  76   * EAP-PAX
  77   * EAP-SAKE
  78   * EAP-IKEv2
  79   * EAP-GPSK
  80   * LEAP (note: requires special support from the driver for IEEE 802.11
  81           authentication)
  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)
  84   * EAP-MD5-Challenge
  85   * EAP-MSCHAPv2
  86   * EAP-GTC
  87   * EAP-OTP
  88 - key management for CCMP, TKIP, WEP104, WEP40
  89 - RSN/WPA2 (IEEE 802.11i)
  90   * pre-authentication
  91   * PMKSA caching
  92
  93 Supported TLS/crypto libraries:
  94 - OpenSSL (default)
  95 - GnuTLS
  96
  97 Internal TLS/crypto implementation (optional):
  98 - can be used in place of an external TLS/crypto library
  99 - TLSv1
 100 - X.509 certificate processing
 101 - PKCS #1
 102 - ASN.1
 103 - RSA
 104 - bignum
 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)
 107
 108
 109 Requirements
 110 ------------
 111
 112 Current hardware/software requirements:
 113 - Linux kernel 2.4.x or 2.6.x with Linux Wireless Extensions v15 or newer
 114 - FreeBSD 6-CURRENT
 115 - NetBSD-current
 116 - Microsoft Windows with WinPcap (at least WinXP, may work with other versions)
 117 - drivers:
 118         Linux drivers that support cfg80211/nl80211. Even though there are
 119         number of driver specific interface included in wpa_supplicant, please
 120         note that Linux drivers are moving to use generic wireless configuration
 121         interface driver_nl80211 (-Dnl80211 on wpa_supplicant command line)
 122         should be the default option to start with before falling back to driver
 123         specific interface.
 124
 125         Linux drivers that support WPA/WPA2 configuration with the generic
 126         Linux wireless extensions (WE-18 or newer). Obsoleted by nl80211.
 127
 128         In theory, any driver that supports Linux wireless extensions can be
 129         used with IEEE 802.1X (i.e., not WPA) when using ap_scan=0 option in
 130         configuration file.
 131
 132         Wired Ethernet drivers (with ap_scan=0)
 133
 134         BSD net80211 layer (e.g., Atheros driver)
 135         At the moment, this is for FreeBSD 6-CURRENT branch and NetBSD-current.
 136
 137         Windows NDIS
 138         The current Windows port requires WinPcap (http://winpcap.polito.it/).
 139         See README-Windows.txt for more information.
 140
 141 wpa_supplicant was designed to be portable for different drivers and
 142 operating systems. Hopefully, support for more wlan cards and OSes will be
 143 added in the future. See developer's documentation
 144 (http://hostap.epitest.fi/wpa_supplicant/devel/) for more information about the
 145 design of wpa_supplicant and porting to other drivers. One main goal
 146 is to add full WPA/WPA2 support to Linux wireless extensions to allow
 147 new drivers to be supported without having to implement new
 148 driver-specific interface code in wpa_supplicant.
 149
 150 Optional libraries for layer2 packet processing:
 151 - libpcap (tested with 0.7.2, most relatively recent versions assumed to work,
 152         this is likely to be available with most distributions,
 153         http://tcpdump.org/)
 154 - libdnet (tested with v1.4, most versions assumed to work,
 155         http://libdnet.sourceforge.net/)
 156
 157 These libraries are _not_ used in the default Linux build. Instead,
 158 internal Linux specific implementation is used. libpcap/libdnet are
 159 more portable and they can be used by adding CONFIG_L2_PACKET=pcap into
 160 .config. They may also be selected automatically for other operating
 161 systems. In case of Windows builds, WinPcap is used by default
 162 (CONFIG_L2_PACKET=winpcap).
 163
 164
 165 Optional libraries for EAP-TLS, EAP-PEAP, and EAP-TTLS:
 166 - OpenSSL (tested with 0.9.7c and 0.9.7d, and 0.9.8 versions; assumed to
 167   work with most relatively recent versions; this is likely to be
 168   available with most distributions, http://www.openssl.org/)
 169 - GnuTLS
 170 - internal TLSv1 implementation
 171
 172 TLS options for EAP-FAST:
 173 - OpenSSL 0.9.8d _with_ openssl-0.9.8d-tls-extensions.patch applied
 174   (i.e., the default OpenSSL package does not include support for
 175   extensions needed for EAP-FAST)
 176 - internal TLSv1 implementation
 177
 178 One of these libraries is needed when EAP-TLS, EAP-PEAP, EAP-TTLS, or
 179 EAP-FAST support is enabled. WPA-PSK mode does not require this or EAPOL/EAP
 180 implementation. A configuration file, .config, for compilation is
 181 needed to enable IEEE 802.1X/EAPOL and EAP methods. Note that EAP-MD5,
 182 EAP-GTC, EAP-OTP, and EAP-MSCHAPV2 cannot be used alone with WPA, so
 183 they should only be enabled if testing the EAPOL/EAP state
 184 machines. However, there can be used as inner authentication
 185 algorithms with EAP-PEAP and EAP-TTLS.
 186
 187 See Building and installing section below for more detailed
 188 information about the wpa_supplicant build time configuration.
 189
 190
 191
 192 WPA
 193 ---
 194
 195 The original security mechanism of IEEE 802.11 standard was not
 196 designed to be strong and has proven to be insufficient for most
 197 networks that require some kind of security. Task group I (Security)
 198 of IEEE 802.11 working group (http://www.ieee802.org/11/) has worked
 199 to address the flaws of the base standard and has in practice
 200 completed its work in May 2004. The IEEE 802.11i amendment to the IEEE
 201 802.11 standard was approved in June 2004 and published in July 2004.
 202
 203 Wi-Fi Alliance (http://www.wi-fi.org/) used a draft version of the
 204 IEEE 802.11i work (draft 3.0) to define a subset of the security
 205 enhancements that can be implemented with existing wlan hardware. This
 206 is called Wi-Fi Protected Access<TM> (WPA). This has now become a
 207 mandatory component of interoperability testing and certification done
 208 by Wi-Fi Alliance. Wi-Fi provides information about WPA at its web
 209 site (http://www.wi-fi.org/OpenSection/protected_access.asp).
 210
 211 IEEE 802.11 standard defined wired equivalent privacy (WEP) algorithm
 212 for protecting wireless networks. WEP uses RC4 with 40-bit keys,
 213 24-bit initialization vector (IV), and CRC32 to protect against packet
 214 forgery. All these choices have proven to be insufficient: key space is
 215 too small against current attacks, RC4 key scheduling is insufficient
 216 (beginning of the pseudorandom stream should be skipped), IV space is
 217 too small and IV reuse makes attacks easier, there is no replay
 218 protection, and non-keyed authentication does not protect against bit
 219 flipping packet data.
 220
 221 WPA is an intermediate solution for the security issues. It uses
 222 Temporal Key Integrity Protocol (TKIP) to replace WEP. TKIP is a
 223 compromise on strong security and possibility to use existing
 224 hardware. It still uses RC4 for the encryption like WEP, but with
 225 per-packet RC4 keys. In addition, it implements replay protection,
 226 keyed packet authentication mechanism (Michael MIC).
 227
 228 Keys can be managed using two different mechanisms. WPA can either use
 229 an external authentication server (e.g., RADIUS) and EAP just like
 230 IEEE 802.1X is using or pre-shared keys without need for additional
 231 servers. Wi-Fi calls these "WPA-Enterprise" and "WPA-Personal",
 232 respectively. Both mechanisms will generate a master session key for
 233 the Authenticator (AP) and Supplicant (client station).
 234
 235 WPA implements a new key handshake (4-Way Handshake and Group Key
 236 Handshake) for generating and exchanging data encryption keys between
 237 the Authenticator and Supplicant. This handshake is also used to
 238 verify that both Authenticator and Supplicant know the master session
 239 key. These handshakes are identical regardless of the selected key
 240 management mechanism (only the method for generating master session
 241 key changes).
 242
 243
 244
 245 IEEE 802.11i / WPA2
 246 -------------------
 247
 248 The design for parts of IEEE 802.11i that were not included in WPA has
 249 finished (May 2004) and this amendment to IEEE 802.11 was approved in
 250 June 2004. Wi-Fi Alliance is using the final IEEE 802.11i as a new
 251 version of WPA called WPA2. This includes, e.g., support for more
 252 robust encryption algorithm (CCMP: AES in Counter mode with CBC-MAC)
 253 to replace TKIP and optimizations for handoff (reduced number of
 254 messages in initial key handshake, pre-authentication, and PMKSA caching).
 255
 256
 257
 258 wpa_supplicant
 259 --------------
 260
 261 wpa_supplicant is an implementation of the WPA Supplicant component,
 262 i.e., the part that runs in the client stations. It implements WPA key
 263 negotiation with a WPA Authenticator and EAP authentication with
 264 Authentication Server. In addition, it controls the roaming and IEEE
 265 802.11 authentication/association of the wlan driver.
 266
 267 wpa_supplicant is designed to be a "daemon" program that runs in the
 268 background and acts as the backend component controlling the wireless
 269 connection. wpa_supplicant supports separate frontend programs and an
 270 example text-based frontend, wpa_cli, is included with wpa_supplicant.
 271
 272 Following steps are used when associating with an AP using WPA:
 273
 274 - wpa_supplicant requests the kernel driver to scan neighboring BSSes
 275 - wpa_supplicant selects a BSS based on its configuration
 276 - wpa_supplicant requests the kernel driver to associate with the chosen
 277   BSS
 278 - If WPA-EAP: integrated IEEE 802.1X Supplicant completes EAP
 279   authentication with the authentication server (proxied by the
 280   Authenticator in the AP)
 281 - If WPA-EAP: master key is received from the IEEE 802.1X Supplicant
 282 - If WPA-PSK: wpa_supplicant uses PSK as the master session key
 283 - wpa_supplicant completes WPA 4-Way Handshake and Group Key Handshake
 284   with the Authenticator (AP)
 285 - wpa_supplicant configures encryption keys for unicast and broadcast
 286 - normal data packets can be transmitted and received
 287
 288
 289
 290 Building and installing
 291 -----------------------
 292
 293 In order to be able to build wpa_supplicant, you will first need to
 294 select which parts of it will be included. This is done by creating a
 295 build time configuration file, .config, in the wpa_supplicant root
 296 directory. Configuration options are text lines using following
 297 format: CONFIG_<option>=y. Lines starting with # are considered
 298 comments and are ignored. See defconfig file for an example configuration
 299 and a list of available options and additional notes.
 300
 301 The build time configuration can be used to select only the needed
 302 features and limit the binary size and requirements for external
 303 libraries. The main configuration parts are the selection of which
 304 driver interfaces (e.g., nl80211, wext, ..) and which authentication
 305 methods (e.g., EAP-TLS, EAP-PEAP, ..) are included.
 306
 307 Following build time configuration options are used to control IEEE
 308 802.1X/EAPOL and EAP state machines and all EAP methods. Including
 309 TLS, PEAP, or TTLS will require linking wpa_supplicant with OpenSSL
 310 library for TLS implementation. Alternatively, GnuTLS or the internal
 311 TLSv1 implementation can be used for TLS functionaly.
 312
 313 CONFIG_IEEE8021X_EAPOL=y
 314 CONFIG_EAP_MD5=y
 315 CONFIG_EAP_MSCHAPV2=y
 316 CONFIG_EAP_TLS=y
 317 CONFIG_EAP_PEAP=y
 318 CONFIG_EAP_TTLS=y
 319 CONFIG_EAP_GTC=y
 320 CONFIG_EAP_OTP=y
 321 CONFIG_EAP_SIM=y
 322 CONFIG_EAP_AKA=y
 323 CONFIG_EAP_PSK=y
 324 CONFIG_EAP_SAKE=y
 325 CONFIG_EAP_GPSK=y
 326 CONFIG_EAP_PAX=y
 327 CONFIG_EAP_LEAP=y
 328 CONFIG_EAP_IKEV2=y
 329
 330 Following option can be used to include GSM SIM/USIM interface for GSM/UMTS
 331 authentication algorithm (for EAP-SIM/EAP-AKA). This requires pcsc-lite
 332 (http://www.linuxnet.com/) for smart card access.
 333
 334 CONFIG_PCSC=y
 335
 336 Following options can be added to .config to select which driver
 337 interfaces are included.
 338
 339 CONFIG_DRIVER_NL80211=y
 340 CONFIG_DRIVER_WEXT=y
 341 CONFIG_DRIVER_BSD=y
 342 CONFIG_DRIVER_NDIS=y
 343
 344 Following example includes some more features and driver interfaces that
 345 are included in the wpa_supplicant package:
 346
 347 CONFIG_DRIVER_NL80211=y
 348 CONFIG_DRIVER_WEXT=y
 349 CONFIG_DRIVER_BSD=y
 350 CONFIG_DRIVER_NDIS=y
 351 CONFIG_IEEE8021X_EAPOL=y
 352 CONFIG_EAP_MD5=y
 353 CONFIG_EAP_MSCHAPV2=y
 354 CONFIG_EAP_TLS=y
 355 CONFIG_EAP_PEAP=y
 356 CONFIG_EAP_TTLS=y
 357 CONFIG_EAP_GTC=y
 358 CONFIG_EAP_OTP=y
 359 CONFIG_EAP_SIM=y
 360 CONFIG_EAP_AKA=y
 361 CONFIG_EAP_PSK=y
 362 CONFIG_EAP_SAKE=y
 363 CONFIG_EAP_GPSK=y
 364 CONFIG_EAP_PAX=y
 365 CONFIG_EAP_LEAP=y
 366 CONFIG_EAP_IKEV2=y
 367 CONFIG_PCSC=y
 368
 369 EAP-PEAP and EAP-TTLS will automatically include configured EAP
 370 methods (MD5, OTP, GTC, MSCHAPV2) for inner authentication selection.
 371
 372
 373 After you have created a configuration file, you can build
 374 wpa_supplicant and wpa_cli with 'make' command. You may then install
 375 the binaries to a suitable system directory, e.g., /usr/local/bin.
 376
 377 Example commands:
 378
 379 # build wpa_supplicant and wpa_cli
 380 make
 381 # install binaries (this may need root privileges)
 382 cp wpa_cli wpa_supplicant /usr/local/bin
 383
 384
 385 You will need to make a configuration file, e.g.,
 386 /etc/wpa_supplicant.conf, with network configuration for the networks
 387 you are going to use. Configuration file section below includes
 388 explanation fo the configuration file format and includes various
 389 examples. Once the configuration is ready, you can test whether the
 390 configuration work by first running wpa_supplicant with following
 391 command to start it on foreground with debugging enabled:
 392
 393 wpa_supplicant -iwlan0 -c/etc/wpa_supplicant.conf -d
 394
 395 Assuming everything goes fine, you can start using following command
 396 to start wpa_supplicant on background without debugging:
 397
 398 wpa_supplicant -iwlan0 -c/etc/wpa_supplicant.conf -B
 399
 400 Please note that if you included more than one driver interface in the
 401 build time configuration (.config), you may need to specify which
 402 interface to use by including -D<driver name> option on the command
 403 line. See following section for more details on command line options
 404 for wpa_supplicant.
 405
 406
 407
 408 Command line options
 409 --------------------
 410
 411 usage:
 412   wpa_supplicant [-BddfhKLqqtuvwW] [-P<pid file>] [-g<global ctrl>] \
 413         -i<ifname> -c<config file> [-C<ctrl>] [-D<driver>] [-p<driver_param>] \
 414         [-b<br_ifname> [-N -i<ifname> -c<conf> [-C<ctrl>] [-D<driver>] \
 415         [-p<driver_param>] [-b<br_ifname>] ...]
 416
 417 options:
 418   -b = optional bridge interface name
 419   -B = run daemon in the background
 420   -c = Configuration file
 421   -C = ctrl_interface parameter (only used if -c is not)
 422   -i = interface name
 423   -d = increase debugging verbosity (-dd even more)
 424   -D = driver name (can be multiple drivers: nl80211,wext)
 425   -f = Log output to default log location (normally /tmp)
 426   -g = global ctrl_interface
 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 interface to be added, if needed
 437   -W = wait for a control interface monitor before starting
 438   -N = start describing new interface
 439
 440 drivers:
 441   nl80211 = Linux nl80211/cfg80211
 442   wext = Linux wireless extensions (generic)
 443   wired = wpa_supplicant wired Ethernet driver
 444   roboswitch = wpa_supplicant Broadcom switch driver
 445   bsd = BSD 802.11 support (Atheros, etc.)
 446   ndis = Windows NDIS driver
 447
 448 In most common cases, wpa_supplicant is started with
 449
 450 wpa_supplicant -B -c/etc/wpa_supplicant.conf -iwlan0
 451
 452 This makes the process fork into background.
 453
 454 The easiest way to debug problems, and to get debug log for bug
 455 reports, is to start wpa_supplicant on foreground with debugging
 456 enabled:
 457
 458 wpa_supplicant -c/etc/wpa_supplicant.conf -iwlan0 -d
 459
 460 If the specific driver wrapper is not known beforehand, it is possible
 461 to specify multiple comma separated driver wrappers on the command
 462 line. wpa_supplicant will use the first driver wrapper that is able to
 463 initialize the interface.
 464
 465 wpa_supplicant -Dnl80211,wext -c/etc/wpa_supplicant.conf -iwlan0
 466
 467
 468 wpa_supplicant can control multiple interfaces (radios) either by
 469 running one process for each interface separately or by running just
 470 one process and list of options at command line. Each interface is
 471 separated with -N argument. As an example, following command would
 472 start wpa_supplicant for two interfaces:
 473
 474 wpa_supplicant \
 475         -c wpa1.conf -i wlan0 -D nl80211 -N \
 476         -c wpa2.conf -i wlan1 -D wext
 477
 478
 479 If the interface is added in a Linux bridge (e.g., br0), the bridge
 480 interface needs to be configured to wpa_supplicant in addition to the
 481 main interface:
 482
 483 wpa_supplicant -cw.conf -Dnl80211 -iwlan0 -bbr0
 484
 485
 486 Configuration file
 487 ------------------
 488
 489 wpa_supplicant is configured using a text file that lists all accepted
 490 networks and security policies, including pre-shared keys. See
 491 example configuration file, wpa_supplicant.conf, for detailed
 492 information about the configuration format and supported fields.
 493
 494 Changes to configuration file can be reloaded be sending SIGHUP signal
 495 to wpa_supplicant ('killall -HUP wpa_supplicant'). Similarly,
 496 reloading can be triggered with 'wpa_cli reconfigure' command.
 497
 498 Configuration file can include one or more network blocks, e.g., one
 499 for each used SSID. wpa_supplicant will automatically select the best
 500 betwork based on the order of network blocks in the configuration
 501 file, network security level (WPA/WPA2 is preferred), and signal
 502 strength.
 503
 504 Example configuration files for some common configurations:
 505
 506 1) WPA-Personal (PSK) as home network and WPA-Enterprise with EAP-TLS as work
 507    network
 508
 509 # allow frontend (e.g., wpa_cli) to be used by all users in 'wheel' group
 510 ctrl_interface=/var/run/wpa_supplicant
 511 ctrl_interface_group=wheel
 512 #
 513 # home network; allow all valid ciphers
 514 network={
 515         ssid="home"
 516         scan_ssid=1
 517         key_mgmt=WPA-PSK
 518         psk="very secret passphrase"
 519 }
 520 #
 521 # work network; use EAP-TLS with WPA; allow only CCMP and TKIP ciphers
 522 network={
 523         ssid="work"
 524         scan_ssid=1
 525         key_mgmt=WPA-EAP
 526         pairwise=CCMP TKIP
 527         group=CCMP TKIP
 528         eap=TLS
 529         identity="user@example.com"
 530         ca_cert="/etc/cert/ca.pem"
 531         client_cert="/etc/cert/user.pem"
 532         private_key="/etc/cert/user.prv"
 533         private_key_passwd="password"
 534 }
 535
 536
 537 2) WPA-RADIUS/EAP-PEAP/MSCHAPv2 with RADIUS servers that use old peaplabel
 538    (e.g., Funk Odyssey and SBR, Meetinghouse Aegis, Interlink RAD-Series)
 539
 540 ctrl_interface=/var/run/wpa_supplicant
 541 ctrl_interface_group=wheel
 542 network={
 543         ssid="example"
 544         scan_ssid=1
 545         key_mgmt=WPA-EAP
 546         eap=PEAP
 547         identity="user@example.com"
 548         password="foobar"
 549         ca_cert="/etc/cert/ca.pem"
 550         phase1="peaplabel=0"
 551         phase2="auth=MSCHAPV2"
 552 }
 553
 554
 555 3) EAP-TTLS/EAP-MD5-Challenge configuration with anonymous identity for the
 556    unencrypted use. Real identity is sent only within an encrypted TLS tunnel.
 557
 558 ctrl_interface=/var/run/wpa_supplicant
 559 ctrl_interface_group=wheel
 560 network={
 561         ssid="example"
 562         scan_ssid=1
 563         key_mgmt=WPA-EAP
 564         eap=TTLS
 565         identity="user@example.com"
 566         anonymous_identity="anonymous@example.com"
 567         password="foobar"
 568         ca_cert="/etc/cert/ca.pem"
 569         phase2="auth=MD5"
 570 }
 571
 572
 573 4) IEEE 802.1X (i.e., no WPA) with dynamic WEP keys (require both unicast and
 574    broadcast); use EAP-TLS for authentication
 575
 576 ctrl_interface=/var/run/wpa_supplicant
 577 ctrl_interface_group=wheel
 578 network={
 579         ssid="1x-test"
 580         scan_ssid=1
 581         key_mgmt=IEEE8021X
 582         eap=TLS
 583         identity="user@example.com"
 584         ca_cert="/etc/cert/ca.pem"
 585         client_cert="/etc/cert/user.pem"
 586         private_key="/etc/cert/user.prv"
 587         private_key_passwd="password"
 588         eapol_flags=3
 589 }
 590
 591
 592 5) Catch all example that allows more or less all configuration modes. The
 593    configuration options are used based on what security policy is used in the
 594    selected SSID. This is mostly for testing and is not recommended for normal
 595    use.
 596
 597 ctrl_interface=/var/run/wpa_supplicant
 598 ctrl_interface_group=wheel
 599 network={
 600         ssid="example"
 601         scan_ssid=1
 602         key_mgmt=WPA-EAP WPA-PSK IEEE8021X NONE
 603         pairwise=CCMP TKIP
 604         group=CCMP TKIP WEP104 WEP40
 605         psk="very secret passphrase"
 606         eap=TTLS PEAP TLS
 607         identity="user@example.com"
 608         password="foobar"
 609         ca_cert="/etc/cert/ca.pem"
 610         client_cert="/etc/cert/user.pem"
 611         private_key="/etc/cert/user.prv"
 612         private_key_passwd="password"
 613         phase1="peaplabel=0"
 614         ca_cert2="/etc/cert/ca2.pem"
 615         client_cert2="/etc/cer/user.pem"
 616         private_key2="/etc/cer/user.prv"
 617         private_key2_passwd="password"
 618 }
 619
 620
 621 6) Authentication for wired Ethernet. This can be used with 'wired' or
 622    'roboswitch' interface (-Dwired or -Droboswitch on command line).
 623
 624 ctrl_interface=/var/run/wpa_supplicant
 625 ctrl_interface_group=wheel
 626 ap_scan=0
 627 network={
 628         key_mgmt=IEEE8021X
 629         eap=MD5
 630         identity="user"
 631         password="password"
 632         eapol_flags=0
 633 }
 634
 635
 636
 637 Certificates
 638 ------------
 639
 640 Some EAP authentication methods require use of certificates. EAP-TLS
 641 uses both server side and client certificates whereas EAP-PEAP and
 642 EAP-TTLS only require the server side certificate. When client
 643 certificate is used, a matching private key file has to also be
 644 included in configuration. If the private key uses a passphrase, this
 645 has to be configured in wpa_supplicant.conf ("private_key_passwd").
 646
 647 wpa_supplicant supports X.509 certificates in PEM and DER
 648 formats. User certificate and private key can be included in the same
 649 file.
 650
 651 If the user certificate and private key is received in PKCS#12/PFX
 652 format, they need to be converted to suitable PEM/DER format for
 653 wpa_supplicant. This can be done, e.g., with following commands:
 654
 655 # convert client certificate and private key to PEM format
 656 openssl pkcs12 -in example.pfx -out user.pem -clcerts
 657 # convert CA certificate (if included in PFX file) to PEM format
 658 openssl pkcs12 -in example.pfx -out ca.pem -cacerts -nokeys
 659
 660
 661
 662 wpa_cli
 663 -------
 664
 665 wpa_cli is a text-based frontend program for interacting with
 666 wpa_supplicant. It is used to query current status, change
 667 configuration, trigger events, and request interactive user input.
 668
 669 wpa_cli can show the current authentication status, selected security
 670 mode, dot11 and dot1x MIBs, etc. In addition, it can configure some
 671 variables like EAPOL state machine parameters and trigger events like
 672 reassociation and IEEE 802.1X logoff/logon. wpa_cli provides a user
 673 interface to request authentication information, like username and
 674 password, if these are not included in the configuration. This can be
 675 used to implement, e.g., one-time-passwords or generic token card
 676 authentication where the authentication is based on a
 677 challenge-response that uses an external device for generating the
 678 response.
 679
 680 The control interface of wpa_supplicant can be configured to allow
 681 non-root user access (ctrl_interface_group in the configuration
 682 file). This makes it possible to run wpa_cli with a normal user
 683 account.
 684
 685 wpa_cli supports two modes: interactive and command line. Both modes
 686 share the same command set and the main difference is in interactive
 687 mode providing access to unsolicited messages (event messages,
 688 username/password requests).
 689
 690 Interactive mode is started when wpa_cli is executed without including
 691 the command as a command line parameter. Commands are then entered on
 692 the wpa_cli prompt. In command line mode, the same commands are
 693 entered as command line arguments for wpa_cli.
 694
 695
 696 Interactive authentication parameters request
 697
 698 When wpa_supplicant need authentication parameters, like username and
 699 password, which are not present in the configuration file, it sends a
 700 request message to all attached frontend programs, e.g., wpa_cli in
 701 interactive mode. wpa_cli shows these requests with
 702 "CTRL-REQ-<type>-<id>:<text>" prefix. <type> is IDENTITY, PASSWORD, or
 703 OTP (one-time-password). <id> is a unique identifier for the current
 704 network. <text> is description of the request. In case of OTP request,
 705 it includes the challenge from the authentication server.
 706
 707 The reply to these requests can be given with 'identity', 'password',
 708 and 'otp' commands. <id> needs to be copied from the the matching
 709 request. 'password' and 'otp' commands can be used regardless of
 710 whether the request was for PASSWORD or OTP. The main difference
 711 between these two commands is that values given with 'password' are
 712 remembered as long as wpa_supplicant is running whereas values given
 713 with 'otp' are used only once and then forgotten, i.e., wpa_supplicant
 714 will ask frontend for a new value for every use. This can be used to
 715 implement one-time-password lists and generic token card -based
 716 authentication.
 717
 718 Example request for password and a matching reply:
 719
 720 CTRL-REQ-PASSWORD-1:Password needed for SSID foobar
 721 > password 1 mysecretpassword
 722
 723 Example request for generic token card challenge-response:
 724
 725 CTRL-REQ-OTP-2:Challenge 1235663 needed for SSID foobar
 726 > otp 2 9876
 727
 728
 729 wpa_cli commands
 730
 731   status = get current WPA/EAPOL/EAP status
 732   mib = get MIB variables (dot1x, dot11)
 733   help = show this usage help
 734   interface [ifname] = show interfaces/select interface
 735   level <debug level> = change debug level
 736   license = show full wpa_cli license
 737   logoff = IEEE 802.1X EAPOL state machine logoff
 738   logon = IEEE 802.1X EAPOL state machine logon
 739   set = set variables (shows list of variables when run without arguments)
 740   pmksa = show PMKSA cache
 741   reassociate = force reassociation
 742   reconfigure = force wpa_supplicant to re-read its configuration file
 743   preauthenticate <BSSID> = force preauthentication
 744   identity <network id> <identity> = configure identity for an SSID
 745   password <network id> <password> = configure password for an SSID
 746   pin <network id> <pin> = configure pin for an SSID
 747   otp <network id> <password> = configure one-time-password for an SSID
 748   passphrase <network id> <passphrase> = configure private key passphrase
 749     for an SSID
 750   bssid <network id> <BSSID> = set preferred BSSID for an SSID
 751   list_networks = list configured networks
 752   select_network <network id> = select a network (disable others)
 753   enable_network <network id> = enable a network
 754   disable_network <network id> = disable a network
 755   add_network = add a network
 756   remove_network <network id> = remove a network
 757   set_network <network id> <variable> <value> = set network variables (shows
 758     list of variables when run without arguments)
 759   get_network <network id> <variable> = get network variables
 760   save_config = save the current configuration
 761   disconnect = disconnect and wait for reassociate command before connecting
 762   scan = request new BSS scan
 763   scan_results = get latest scan results
 764   get_capability <eap/pairwise/group/key_mgmt/proto/auth_alg> = get capabilies
 765   terminate = terminate wpa_supplicant
 766   quit = exit wpa_cli
 767
 768
 769 wpa_cli command line options
 770
 771 wpa_cli [-p<path to ctrl sockets>] [-i<ifname>] [-hvB] [-a<action file>] \
 772         [-P<pid file>] [-g<global ctrl>]  [command..]
 773   -h = help (show this usage text)
 774   -v = shown version information
 775   -a = run in daemon mode executing the action file based on events from
 776        wpa_supplicant
 777   -B = run a daemon in the background
 778   default path: /var/run/wpa_supplicant
 779   default interface: first interface found in socket path
 780
 781
 782 Using wpa_cli to run external program on connect/disconnect
 783 -----------------------------------------------------------
 784
 785 wpa_cli can used to run external programs whenever wpa_supplicant
 786 connects or disconnects from a network. This can be used, e.g., to
 787 update network configuration and/or trigget DHCP client to update IP
 788 addresses, etc.
 789
 790 One wpa_cli process in "action" mode needs to be started for each
 791 interface. For example, the following command starts wpa_cli for the
 792 default ingterface (-i can be used to select the interface in case of
 793 more than one interface being used at the same time):
 794
 795 wpa_cli -a/sbin/wpa_action.sh -B
 796
 797 The action file (-a option, /sbin/wpa_action.sh in this example) will
 798 be executed whenever wpa_supplicant completes authentication (connect
 799 event) or detects disconnection). The action script will be called
 800 with two command line arguments: interface name and event (CONNECTED
 801 or DISCONNECTED). If the action script needs to get more information
 802 about the current network, it can use 'wpa_cli status' to query
 803 wpa_supplicant for more information.
 804
 805 Following example can be used as a simple template for an action
 806 script:
 807
 808 #!/bin/sh
 809
 810 IFNAME=$1
 811 CMD=$2
 812
 813 if [ "$CMD" = "CONNECTED" ]; then
 814     SSID=`wpa_cli -i$IFNAME status | grep ^ssid= | cut -f2- -d=`
 815     # configure network, signal DHCP client, etc.
 816 fi
 817
 818 if [ "$CMD" = "DISCONNECTED" ]; then
 819     # remove network configuration, if needed
 820     SSID=
 821 fi
 822
 823
 824
 825 Integrating with pcmcia-cs/cardmgr scripts
 826 ------------------------------------------
 827
 828 wpa_supplicant needs to be running when using a wireless network with
 829 WPA. It can be started either from system startup scripts or from
 830 pcmcia-cs/cardmgr scripts (when using PC Cards). WPA handshake must be
 831 completed before data frames can be exchanged, so wpa_supplicant
 832 should be started before DHCP client.
 833
 834 For example, following small changes to pcmcia-cs scripts can be used
 835 to enable WPA support:
 836
 837 Add MODE="Managed" and WPA="y" to the network scheme in
 838 /etc/pcmcia/wireless.opts.
 839
 840 Add the following block to the end of 'start' action handler in
 841 /etc/pcmcia/wireless:
 842
 843     if [ "$WPA" = "y" -a -x /usr/local/bin/wpa_supplicant ]; then
 844         /usr/local/bin/wpa_supplicant -B -c/etc/wpa_supplicant.conf \
 845                 -i$DEVICE
 846     fi
 847
 848 Add the following block to the end of 'stop' action handler (may need
 849 to be separated from other actions) in /etc/pcmcia/wireless:
 850
 851     if [ "$WPA" = "y" -a -x /usr/local/bin/wpa_supplicant ]; then
 852         killall wpa_supplicant
 853     fi
 854
 855 This will make cardmgr start wpa_supplicant when the card is plugged
 856 in.
 857
 858
 859
 860 Dynamic interface add and operation without configuration files
 861 ---------------------------------------------------------------
 862
 863 wpa_supplicant can be started without any configuration files or
 864 network interfaces. When used in this way, a global (i.e., per
 865 wpa_supplicant process) control interface is used to add and remove
 866 network interfaces. Each network interface can then be configured
 867 through a per-network interface control interface. For example,
 868 following commands show how to start wpa_supplicant without any
 869 network interfaces and then add a network interface and configure a
 870 network (SSID):
 871
 872 # Start wpa_supplicant in the background
 873 wpa_supplicant -g/var/run/wpa_supplicant-global -B
 874
 875 # Add a new interface (wlan0, no configuration file, driver=nl80211, and
 876 # enable control interface)
 877 wpa_cli -g/var/run/wpa_supplicant-global interface_add wlan0 \
 878         "" nl80211 /var/run/wpa_supplicant
 879
 880 # Configure a network using the newly added network interface:
 881 wpa_cli -iwlan0 add_network
 882 wpa_cli -iwlan0 set_network 0 ssid '"test"'
 883 wpa_cli -iwlan0 set_network 0 key_mgmt WPA-PSK
 884 wpa_cli -iwlan0 set_network 0 psk '"12345678"'
 885 wpa_cli -iwlan0 set_network 0 pairwise TKIP
 886 wpa_cli -iwlan0 set_network 0 group TKIP
 887 wpa_cli -iwlan0 set_network 0 proto WPA
 888 wpa_cli -iwlan0 enable_network 0
 889
 890 # At this point, the new network interface should start trying to associate
 891 # with the WPA-PSK network using SSID test.
 892
 893 # Remove network interface
 894 wpa_cli -g/var/run/wpa_supplicant-global interface_remove wlan0
 895
 896
 897 Privilege separation
 898 --------------------
 899
 900 To minimize the size of code that needs to be run with root privileges
 901 (e.g., to control wireless interface operation), wpa_supplicant
 902 supports optional privilege separation. If enabled, this separates the
 903 privileged operations into a separate process (wpa_priv) while leaving
 904 rest of the code (e.g., EAP authentication and WPA handshakes) into an
 905 unprivileged process (wpa_supplicant) that can be run as non-root
 906 user. Privilege separation restricts the effects of potential software
 907 errors by containing the majority of the code in an unprivileged
 908 process to avoid full system compromise.
 909
 910 Privilege separation is not enabled by default and it can be enabled
 911 by adding CONFIG_PRIVSEP=y to the build configuration (.config). When
 912 enabled, the privileged operations (driver wrapper and l2_packet) are
 913 linked into a separate daemon program, wpa_priv. The unprivileged
 914 program, wpa_supplicant, will be built with a special driver/l2_packet
 915 wrappers that communicate with the privileged wpa_priv process to
 916 perform the needed operations. wpa_priv can control what privileged
 917 are allowed.
 918
 919 wpa_priv needs to be run with network admin privileges (usually, root
 920 user). It opens a UNIX domain socket for each interface that is
 921 included on the command line; any other interface will be off limits
 922 for wpa_supplicant in this kind of configuration. After this,
 923 wpa_supplicant can be run as a non-root user (e.g., all standard users
 924 on a laptop or as a special non-privileged user account created just
 925 for this purpose to limit access to user files even further).
 926
 927
 928 Example configuration:
 929 - create user group for users that are allowed to use wpa_supplicant
 930   ('wpapriv' in this example) and assign users that should be able to
 931   use wpa_supplicant into that group
 932 - create /var/run/wpa_priv directory for UNIX domain sockets and control
 933   user access by setting it accessible only for the wpapriv group:
 934   mkdir /var/run/wpa_priv
 935   chown root:wpapriv /var/run/wpa_priv
 936   chmod 0750 /var/run/wpa_priv
 937 - start wpa_priv as root (e.g., from system startup scripts) with the
 938   enabled interfaces configured on the command line:
 939   wpa_priv -B -P /var/run/wpa_priv.pid nl80211:wlan0
 940 - run wpa_supplicant as non-root with a user that is in wpapriv group:
 941   wpa_supplicant -i ath0 -c wpa_supplicant.conf
 942
 943 wpa_priv does not use the network interface before wpa_supplicant is
 944 started, so it is fine to include network interfaces that are not
 945 available at the time wpa_priv is started. As an alternative, wpa_priv
 946 can be started when an interface is added (hotplug/udev/etc. scripts).
 947 wpa_priv can control multiple interface with one process, but it is
 948 also possible to run multiple wpa_priv processes at the same time, if
 949 desired.