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Copyright (c) 2003-2010, Jouni Malinen <j@w1.fi> and contributors
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This program is dual-licensed under both the GPL version 2 and BSD
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license. Either license may be used at your option.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License version 2 as
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published by the Free Software Foundation.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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(this copy of the license is in COPYING file)
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Alternatively, this software may be distributed, used, and modified
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under the terms of BSD license:
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are
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1. Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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2. Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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3. Neither the name(s) of the above-listed copyright holder(s) nor the
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names of its contributors may be used to endorse or promote products
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derived from this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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Supported WPA/IEEE 802.11i features:
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- WPA-PSK ("WPA-Personal")
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- WPA with EAP (e.g., with RADIUS authentication server) ("WPA-Enterprise")
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Following authentication methods are supported with an integrate IEEE 802.1X
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* EAP-PEAP/MSCHAPv2 (both PEAPv0 and PEAPv1)
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* EAP-PEAP/TLS (both PEAPv0 and PEAPv1)
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* EAP-PEAP/GTC (both PEAPv0 and PEAPv1)
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* EAP-PEAP/OTP (both PEAPv0 and PEAPv1)
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* EAP-PEAP/MD5-Challenge (both PEAPv0 and PEAPv1)
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* EAP-TTLS/EAP-MD5-Challenge
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* EAP-TTLS/EAP-MSCHAPv2
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* LEAP (note: requires special support from the driver for IEEE 802.11
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(following methods are supported, but since they do not generate keying
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material, they cannot be used with WPA or IEEE 802.1X WEP keying)
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- key management for CCMP, TKIP, WEP104, WEP40
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- RSN/WPA2 (IEEE 802.11i)
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Supported TLS/crypto libraries:
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Internal TLS/crypto implementation (optional):
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- can be used in place of an external TLS/crypto library
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- X.509 certificate processing
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- minimal size (ca. 50 kB binary, parts of which are already needed for WPA;
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TLSv1/X.509/ASN.1/RSA/bignum parts are about 25 kB on x86)
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Current hardware/software requirements:
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- Linux kernel 2.4.x or 2.6.x with Linux Wireless Extensions v15 or newer
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- Microsoft Windows with WinPcap (at least WinXP, may work with other versions)
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Linux drivers that support WPA/WPA2 configuration with the generic
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Linux wireless extensions (WE-18 or newer). Even though there are
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number of driver specific interface included in wpa_supplicant, please
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note that Linux drivers are moving to use generic wireless extensions
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and driver_wext (-Dwext on wpa_supplicant command line) should be the
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default option to start with before falling back to driver specific
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Host AP driver for Prism2/2.5/3 (development snapshot/v0.2.x)
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(http://hostap.epitest.fi/)
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Driver need to be set in Managed mode ('iwconfig wlan0 mode managed').
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Please note that station firmware version needs to be 1.7.0 or newer
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Linuxant DriverLoader (http://www.linuxant.com/driverloader/)
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with Windows NDIS driver for your wlan card supporting WPA.
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Agere Systems Inc. Linux Driver
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(http://www.agere.com/support/drivers/)
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Please note that the driver interface file (driver_hermes.c) and
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hardware specific include files are not included in the
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wpa_supplicant distribution. You will need to copy these from the
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source package of the Agere driver.
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madwifi driver for cards based on Atheros chip set (ar521x)
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(http://sourceforge.net/projects/madwifi/)
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Please note that you will need to modify the wpa_supplicant .config
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file to use the correct path for the madwifi driver root directory
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(CFLAGS += -I../madwifi/wpa line in example defconfig).
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ATMEL AT76C5XXx driver for USB and PCMCIA cards
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(http://atmelwlandriver.sourceforge.net/).
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Linux ndiswrapper (http://ndiswrapper.sourceforge.net/) with
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Broadcom wl.o driver (old version only)
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This is a generic Linux driver for Broadcom IEEE 802.11a/g cards.
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However, it is proprietary driver that is not publicly available
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except for couple of exceptions, mainly Broadcom-based APs/wireless
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routers that use Linux. The driver binary can be downloaded, e.g.,
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from Linksys support site (http://www.linksys.com/support/gpl.asp)
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for Linksys WRT54G. The GPL tarball includes cross-compiler and
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the needed header file, wlioctl.h, for compiling wpa_supplicant.
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This driver support in wpa_supplicant is expected to work also with
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other devices based on Broadcom driver (assuming the driver includes
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client mode support). Please note that the newer Broadcom driver
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("hybrid Linux driver") supports Linux wireless extensions and does
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not need (or even work) with the specific driver wrapper. Use -Dwext
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(http://sourceforge.net/projects/ipw2100/)
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(http://sourceforge.net/projects/ipw2200/)
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In theory, any driver that supports Linux wireless extensions can be
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used with IEEE 802.1X (i.e., not WPA) when using ap_scan=0 option in
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Wired Ethernet drivers (with ap_scan=0)
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BSD net80211 layer (e.g., Atheros driver)
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At the moment, this is for FreeBSD 6-CURRENT branch and NetBSD-current.
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The current Windows port requires WinPcap (http://winpcap.polito.it/).
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See README-Windows.txt for more information.
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wpa_supplicant was designed to be portable for different drivers and
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operating systems. Hopefully, support for more wlan cards and OSes will be
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added in the future. See developer's documentation
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(http://hostap.epitest.fi/wpa_supplicant/devel/) for more information about the
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design of wpa_supplicant and porting to other drivers. One main goal
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is to add full WPA/WPA2 support to Linux wireless extensions to allow
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new drivers to be supported without having to implement new
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driver-specific interface code in wpa_supplicant.
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Optional libraries for layer2 packet processing:
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- libpcap (tested with 0.7.2, most relatively recent versions assumed to work,
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this is likely to be available with most distributions,
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- libdnet (tested with v1.4, most versions assumed to work,
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http://libdnet.sourceforge.net/)
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These libraries are _not_ used in the default Linux build. Instead,
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internal Linux specific implementation is used. libpcap/libdnet are
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more portable and they can be used by adding CONFIG_L2_PACKET=pcap into
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.config. They may also be selected automatically for other operating
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systems. In case of Windows builds, WinPcap is used by default
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(CONFIG_L2_PACKET=winpcap).
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Optional libraries for EAP-TLS, EAP-PEAP, and EAP-TTLS:
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- OpenSSL (tested with 0.9.7c and 0.9.7d, and 0.9.8 versions; assumed to
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work with most relatively recent versions; this is likely to be
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available with most distributions, http://www.openssl.org/)
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- internal TLSv1 implementation
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TLS options for EAP-FAST:
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- OpenSSL 0.9.8d _with_ openssl-0.9.8d-tls-extensions.patch applied
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(i.e., the default OpenSSL package does not include support for
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extensions needed for EAP-FAST)
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- internal TLSv1 implementation
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One of these libraries is needed when EAP-TLS, EAP-PEAP, EAP-TTLS, or
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EAP-FAST support is enabled. WPA-PSK mode does not require this or EAPOL/EAP
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implementation. A configuration file, .config, for compilation is
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needed to enable IEEE 802.1X/EAPOL and EAP methods. Note that EAP-MD5,
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EAP-GTC, EAP-OTP, and EAP-MSCHAPV2 cannot be used alone with WPA, so
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they should only be enabled if testing the EAPOL/EAP state
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machines. However, there can be used as inner authentication
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algorithms with EAP-PEAP and EAP-TTLS.
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See Building and installing section below for more detailed
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information about the wpa_supplicant build time configuration.
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The original security mechanism of IEEE 802.11 standard was not
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designed to be strong and has proven to be insufficient for most
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networks that require some kind of security. Task group I (Security)
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of IEEE 802.11 working group (http://www.ieee802.org/11/) has worked
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to address the flaws of the base standard and has in practice
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completed its work in May 2004. The IEEE 802.11i amendment to the IEEE
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802.11 standard was approved in June 2004 and published in July 2004.
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Wi-Fi Alliance (http://www.wi-fi.org/) used a draft version of the
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IEEE 802.11i work (draft 3.0) to define a subset of the security
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enhancements that can be implemented with existing wlan hardware. This
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is called Wi-Fi Protected Access<TM> (WPA). This has now become a
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mandatory component of interoperability testing and certification done
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by Wi-Fi Alliance. Wi-Fi provides information about WPA at its web
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site (http://www.wi-fi.org/OpenSection/protected_access.asp).
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IEEE 802.11 standard defined wired equivalent privacy (WEP) algorithm
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for protecting wireless networks. WEP uses RC4 with 40-bit keys,
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24-bit initialization vector (IV), and CRC32 to protect against packet
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forgery. All these choices have proven to be insufficient: key space is
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too small against current attacks, RC4 key scheduling is insufficient
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(beginning of the pseudorandom stream should be skipped), IV space is
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too small and IV reuse makes attacks easier, there is no replay
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protection, and non-keyed authentication does not protect against bit
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flipping packet data.
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WPA is an intermediate solution for the security issues. It uses
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Temporal Key Integrity Protocol (TKIP) to replace WEP. TKIP is a
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compromise on strong security and possibility to use existing
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hardware. It still uses RC4 for the encryption like WEP, but with
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per-packet RC4 keys. In addition, it implements replay protection,
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keyed packet authentication mechanism (Michael MIC).
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Keys can be managed using two different mechanisms. WPA can either use
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an external authentication server (e.g., RADIUS) and EAP just like
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IEEE 802.1X is using or pre-shared keys without need for additional
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servers. Wi-Fi calls these "WPA-Enterprise" and "WPA-Personal",
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respectively. Both mechanisms will generate a master session key for
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the Authenticator (AP) and Supplicant (client station).
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WPA implements a new key handshake (4-Way Handshake and Group Key
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Handshake) for generating and exchanging data encryption keys between
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the Authenticator and Supplicant. This handshake is also used to
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verify that both Authenticator and Supplicant know the master session
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key. These handshakes are identical regardless of the selected key
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management mechanism (only the method for generating master session
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The design for parts of IEEE 802.11i that were not included in WPA has
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finished (May 2004) and this amendment to IEEE 802.11 was approved in
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June 2004. Wi-Fi Alliance is using the final IEEE 802.11i as a new
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version of WPA called WPA2. This includes, e.g., support for more
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robust encryption algorithm (CCMP: AES in Counter mode with CBC-MAC)
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to replace TKIP and optimizations for handoff (reduced number of
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messages in initial key handshake, pre-authentication, and PMKSA caching).
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wpa_supplicant is an implementation of the WPA Supplicant component,
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i.e., the part that runs in the client stations. It implements WPA key
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negotiation with a WPA Authenticator and EAP authentication with
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Authentication Server. In addition, it controls the roaming and IEEE
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802.11 authentication/association of the wlan driver.
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wpa_supplicant is designed to be a "daemon" program that runs in the
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background and acts as the backend component controlling the wireless
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connection. wpa_supplicant supports separate frontend programs and an
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example text-based frontend, wpa_cli, is included with wpa_supplicant.
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Following steps are used when associating with an AP using WPA:
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- wpa_supplicant requests the kernel driver to scan neighboring BSSes
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- wpa_supplicant selects a BSS based on its configuration
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- wpa_supplicant requests the kernel driver to associate with the chosen
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- If WPA-EAP: integrated IEEE 802.1X Supplicant completes EAP
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authentication with the authentication server (proxied by the
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Authenticator in the AP)
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- If WPA-EAP: master key is received from the IEEE 802.1X Supplicant
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- If WPA-PSK: wpa_supplicant uses PSK as the master session key
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- wpa_supplicant completes WPA 4-Way Handshake and Group Key Handshake
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with the Authenticator (AP)
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- wpa_supplicant configures encryption keys for unicast and broadcast
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- normal data packets can be transmitted and received
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Building and installing
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-----------------------
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In order to be able to build wpa_supplicant, you will first need to
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select which parts of it will be included. This is done by creating a
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build time configuration file, .config, in the wpa_supplicant root
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directory. Configuration options are text lines using following
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format: CONFIG_<option>=y. Lines starting with # are considered
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comments and are ignored. See defconfig file for an example configuration
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and a list of available options and additional notes.
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The build time configuration can be used to select only the needed
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features and limit the binary size and requirements for external
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libraries. The main configuration parts are the selection of which
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driver interfaces (e.g., hostap, madwifi, ..) and which authentication
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methods (e.g., EAP-TLS, EAP-PEAP, ..) are included.
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Following build time configuration options are used to control IEEE
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802.1X/EAPOL and EAP state machines and all EAP methods. Including
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TLS, PEAP, or TTLS will require linking wpa_supplicant with OpenSSL
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library for TLS implementation. Alternatively, GnuTLS or the internal
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TLSv1 implementation can be used for TLS functionaly.
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CONFIG_IEEE8021X_EAPOL=y
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CONFIG_EAP_MSCHAPV2=y
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Following option can be used to include GSM SIM/USIM interface for GSM/UMTS
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authentication algorithm (for EAP-SIM/EAP-AKA). This requires pcsc-lite
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(http://www.linuxnet.com/) for smart card access.
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Following options can be added to .config to select which driver
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interfaces are included. Hermes driver interface needs to be downloaded
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from Agere (see above).
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CONFIG_DRIVER_HOSTAP=y
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CONFIG_DRIVER_HERMES=y
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CONFIG_DRIVER_MADWIFI=y
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CONFIG_DRIVER_ATMEL=y
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CONFIG_DRIVER_RALINK=y
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CONFIG_DRIVER_NDISWRAPPER=y
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CONFIG_DRIVER_BROADCOM=y
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Following example includes all features and driver interfaces that are
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included in the wpa_supplicant package:
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CONFIG_DRIVER_HOSTAP=y
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CONFIG_DRIVER_HERMES=y
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CONFIG_DRIVER_MADWIFI=y
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CONFIG_DRIVER_ATMEL=y
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CONFIG_DRIVER_NDISWRAPPER=y
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CONFIG_DRIVER_BROADCOM=y
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CONFIG_IEEE8021X_EAPOL=y
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CONFIG_EAP_MSCHAPV2=y
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EAP-PEAP and EAP-TTLS will automatically include configured EAP
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methods (MD5, OTP, GTC, MSCHAPV2) for inner authentication selection.
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After you have created a configuration file, you can build
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wpa_supplicant and wpa_cli with 'make' command. You may then install
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the binaries to a suitable system directory, e.g., /usr/local/bin.
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# build wpa_supplicant and wpa_cli
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# install binaries (this may need root privileges)
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cp wpa_cli wpa_supplicant /usr/local/bin
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You will need to make a configuration file, e.g.,
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/etc/wpa_supplicant.conf, with network configuration for the networks
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you are going to use. Configuration file section below includes
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explanation fo the configuration file format and includes various
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examples. Once the configuration is ready, you can test whether the
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configuration work by first running wpa_supplicant with following
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command to start it on foreground with debugging enabled:
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wpa_supplicant -iwlan0 -c/etc/wpa_supplicant.conf -d
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Assuming everything goes fine, you can start using following command
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to start wpa_supplicant on background without debugging:
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wpa_supplicant -iwlan0 -c/etc/wpa_supplicant.conf -B
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Please note that if you included more than one driver interface in the
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build time configuration (.config), you may need to specify which
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interface to use by including -D<driver name> option on the command
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line. See following section for more details on command line options
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wpa_supplicant [-BddfhKLqqtuvwW] [-P<pid file>] [-g<global ctrl>] \
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-i<ifname> -c<config file> [-C<ctrl>] [-D<driver>] [-p<driver_param>] \
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[-b<br_ifname> [-N -i<ifname> -c<conf> [-C<ctrl>] [-D<driver>] \
491
[-p<driver_param>] [-b<br_ifname>] ...]
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-b = optional bridge interface name
495
-B = run daemon in the background
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-c = Configuration file
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-C = ctrl_interface parameter (only used if -c is not)
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-d = increase debugging verbosity (-dd even more)
500
-D = driver name (can be multiple drivers: nl80211,wext)
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-f = Log output to default log location (normally /tmp)
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-g = global ctrl_interface
503
-K = include keys (passwords, etc.) in debug output
504
-t = include timestamp in debug messages
505
-h = show this help text
506
-L = show license (GPL and BSD)
507
-p = driver parameters
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-q = decrease debugging verbosity (-qq even less)
510
-u = enable DBus control interface
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-w = wait for interface to be added, if needed
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-W = wait for a control interface monitor before starting
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-N = start describing new interface
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hostap = Host AP driver (Intersil Prism2/2.5/3) [default]
518
(this can also be used with Linuxant DriverLoader)
519
hermes = Agere Systems Inc. driver (Hermes-I/Hermes-II)
520
madwifi = MADWIFI 802.11 support (Atheros, etc.) (deprecated; use wext)
521
atmel = ATMEL AT76C5XXx (USB, PCMCIA)
522
wext = Linux wireless extensions (generic)
523
ralink = Ralink Client driver
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ndiswrapper = Linux ndiswrapper (deprecated; use wext)
525
broadcom = Broadcom wl.o driver
526
ipw = Intel ipw2100/2200 driver (old; use wext with Linux 2.6.13 or newer)
527
wired = wpa_supplicant wired Ethernet driver
528
roboswitch = wpa_supplicant Broadcom switch driver
529
bsd = BSD 802.11 support (Atheros, etc.)
530
ndis = Windows NDIS driver
532
In most common cases, wpa_supplicant is started with
534
wpa_supplicant -B -c/etc/wpa_supplicant.conf -iwlan0
536
This makes the process fork into background.
538
The easiest way to debug problems, and to get debug log for bug
539
reports, is to start wpa_supplicant on foreground with debugging
542
wpa_supplicant -c/etc/wpa_supplicant.conf -iwlan0 -d
544
If the specific driver wrapper is not known beforehand, it is possible
545
to specify multiple comma separated driver wrappers on the command
546
line. wpa_supplicant will use the first driver wrapper that is able to
547
initialize the interface.
549
wpa_supplicant -Dnl80211,wext -c/etc/wpa_supplicant.conf -iwlan0
552
wpa_supplicant can control multiple interfaces (radios) either by
553
running one process for each interface separately or by running just
554
one process and list of options at command line. Each interface is
555
separated with -N argument. As an example, following command would
556
start wpa_supplicant for two interfaces:
559
-c wpa1.conf -i wlan0 -D hostap -N \
560
-c wpa2.conf -i ath0 -D madwifi
563
If the interface is added in a Linux bridge (e.g., br0), the bridge
564
interface needs to be configured to wpa_supplicant in addition to the
567
wpa_supplicant -cw.conf -Dmadwifi -iath0 -bbr0
573
wpa_supplicant is configured using a text file that lists all accepted
574
networks and security policies, including pre-shared keys. See
575
example configuration file, wpa_supplicant.conf, for detailed
576
information about the configuration format and supported fields.
578
Changes to configuration file can be reloaded be sending SIGHUP signal
579
to wpa_supplicant ('killall -HUP wpa_supplicant'). Similarly,
580
reloading can be triggered with 'wpa_cli reconfigure' command.
582
Configuration file can include one or more network blocks, e.g., one
583
for each used SSID. wpa_supplicant will automatically select the best
584
betwork based on the order of network blocks in the configuration
585
file, network security level (WPA/WPA2 is preferred), and signal
588
Example configuration files for some common configurations:
590
1) WPA-Personal (PSK) as home network and WPA-Enterprise with EAP-TLS as work
593
# allow frontend (e.g., wpa_cli) to be used by all users in 'wheel' group
594
ctrl_interface=/var/run/wpa_supplicant
595
ctrl_interface_group=wheel
597
# home network; allow all valid ciphers
602
psk="very secret passphrase"
605
# work network; use EAP-TLS with WPA; allow only CCMP and TKIP ciphers
613
identity="user@example.com"
614
ca_cert="/etc/cert/ca.pem"
615
client_cert="/etc/cert/user.pem"
616
private_key="/etc/cert/user.prv"
617
private_key_passwd="password"
621
2) WPA-RADIUS/EAP-PEAP/MSCHAPv2 with RADIUS servers that use old peaplabel
622
(e.g., Funk Odyssey and SBR, Meetinghouse Aegis, Interlink RAD-Series)
624
ctrl_interface=/var/run/wpa_supplicant
625
ctrl_interface_group=wheel
631
identity="user@example.com"
633
ca_cert="/etc/cert/ca.pem"
635
phase2="auth=MSCHAPV2"
639
3) EAP-TTLS/EAP-MD5-Challenge configuration with anonymous identity for the
640
unencrypted use. Real identity is sent only within an encrypted TLS tunnel.
642
ctrl_interface=/var/run/wpa_supplicant
643
ctrl_interface_group=wheel
649
identity="user@example.com"
650
anonymous_identity="anonymous@example.com"
652
ca_cert="/etc/cert/ca.pem"
657
4) IEEE 802.1X (i.e., no WPA) with dynamic WEP keys (require both unicast and
658
broadcast); use EAP-TLS for authentication
660
ctrl_interface=/var/run/wpa_supplicant
661
ctrl_interface_group=wheel
667
identity="user@example.com"
668
ca_cert="/etc/cert/ca.pem"
669
client_cert="/etc/cert/user.pem"
670
private_key="/etc/cert/user.prv"
671
private_key_passwd="password"
676
5) Catch all example that allows more or less all configuration modes. The
677
configuration options are used based on what security policy is used in the
678
selected SSID. This is mostly for testing and is not recommended for normal
681
ctrl_interface=/var/run/wpa_supplicant
682
ctrl_interface_group=wheel
686
key_mgmt=WPA-EAP WPA-PSK IEEE8021X NONE
688
group=CCMP TKIP WEP104 WEP40
689
psk="very secret passphrase"
691
identity="user@example.com"
693
ca_cert="/etc/cert/ca.pem"
694
client_cert="/etc/cert/user.pem"
695
private_key="/etc/cert/user.prv"
696
private_key_passwd="password"
698
ca_cert2="/etc/cert/ca2.pem"
699
client_cert2="/etc/cer/user.pem"
700
private_key2="/etc/cer/user.prv"
701
private_key2_passwd="password"
705
6) Authentication for wired Ethernet. This can be used with 'wired' or
706
'roboswitch' interface (-Dwired or -Droboswitch on command line).
708
ctrl_interface=/var/run/wpa_supplicant
709
ctrl_interface_group=wheel
724
Some EAP authentication methods require use of certificates. EAP-TLS
725
uses both server side and client certificates whereas EAP-PEAP and
726
EAP-TTLS only require the server side certificate. When client
727
certificate is used, a matching private key file has to also be
728
included in configuration. If the private key uses a passphrase, this
729
has to be configured in wpa_supplicant.conf ("private_key_passwd").
731
wpa_supplicant supports X.509 certificates in PEM and DER
732
formats. User certificate and private key can be included in the same
735
If the user certificate and private key is received in PKCS#12/PFX
736
format, they need to be converted to suitable PEM/DER format for
737
wpa_supplicant. This can be done, e.g., with following commands:
739
# convert client certificate and private key to PEM format
740
openssl pkcs12 -in example.pfx -out user.pem -clcerts
741
# convert CA certificate (if included in PFX file) to PEM format
742
openssl pkcs12 -in example.pfx -out ca.pem -cacerts -nokeys
749
wpa_cli is a text-based frontend program for interacting with
750
wpa_supplicant. It is used to query current status, change
751
configuration, trigger events, and request interactive user input.
753
wpa_cli can show the current authentication status, selected security
754
mode, dot11 and dot1x MIBs, etc. In addition, it can configure some
755
variables like EAPOL state machine parameters and trigger events like
756
reassociation and IEEE 802.1X logoff/logon. wpa_cli provides a user
757
interface to request authentication information, like username and
758
password, if these are not included in the configuration. This can be
759
used to implement, e.g., one-time-passwords or generic token card
760
authentication where the authentication is based on a
761
challenge-response that uses an external device for generating the
764
The control interface of wpa_supplicant can be configured to allow
765
non-root user access (ctrl_interface_group in the configuration
766
file). This makes it possible to run wpa_cli with a normal user
769
wpa_cli supports two modes: interactive and command line. Both modes
770
share the same command set and the main difference is in interactive
771
mode providing access to unsolicited messages (event messages,
772
username/password requests).
774
Interactive mode is started when wpa_cli is executed without including
775
the command as a command line parameter. Commands are then entered on
776
the wpa_cli prompt. In command line mode, the same commands are
777
entered as command line arguments for wpa_cli.
780
Interactive authentication parameters request
782
When wpa_supplicant need authentication parameters, like username and
783
password, which are not present in the configuration file, it sends a
784
request message to all attached frontend programs, e.g., wpa_cli in
785
interactive mode. wpa_cli shows these requests with
786
"CTRL-REQ-<type>-<id>:<text>" prefix. <type> is IDENTITY, PASSWORD, or
787
OTP (one-time-password). <id> is a unique identifier for the current
788
network. <text> is description of the request. In case of OTP request,
789
it includes the challenge from the authentication server.
791
The reply to these requests can be given with 'identity', 'password',
792
and 'otp' commands. <id> needs to be copied from the the matching
793
request. 'password' and 'otp' commands can be used regardless of
794
whether the request was for PASSWORD or OTP. The main difference
795
between these two commands is that values given with 'password' are
796
remembered as long as wpa_supplicant is running whereas values given
797
with 'otp' are used only once and then forgotten, i.e., wpa_supplicant
798
will ask frontend for a new value for every use. This can be used to
799
implement one-time-password lists and generic token card -based
802
Example request for password and a matching reply:
804
CTRL-REQ-PASSWORD-1:Password needed for SSID foobar
805
> password 1 mysecretpassword
807
Example request for generic token card challenge-response:
809
CTRL-REQ-OTP-2:Challenge 1235663 needed for SSID foobar
815
status = get current WPA/EAPOL/EAP status
816
mib = get MIB variables (dot1x, dot11)
817
help = show this usage help
818
interface [ifname] = show interfaces/select interface
819
level <debug level> = change debug level
820
license = show full wpa_cli license
821
logoff = IEEE 802.1X EAPOL state machine logoff
822
logon = IEEE 802.1X EAPOL state machine logon
823
set = set variables (shows list of variables when run without arguments)
824
pmksa = show PMKSA cache
825
reassociate = force reassociation
826
reconfigure = force wpa_supplicant to re-read its configuration file
827
preauthenticate <BSSID> = force preauthentication
828
identity <network id> <identity> = configure identity for an SSID
829
password <network id> <password> = configure password for an SSID
830
pin <network id> <pin> = configure pin for an SSID
831
otp <network id> <password> = configure one-time-password for an SSID
832
passphrase <network id> <passphrase> = configure private key passphrase
834
bssid <network id> <BSSID> = set preferred BSSID for an SSID
835
list_networks = list configured networks
836
select_network <network id> = select a network (disable others)
837
enable_network <network id> = enable a network
838
disable_network <network id> = disable a network
839
add_network = add a network
840
remove_network <network id> = remove a network
841
set_network <network id> <variable> <value> = set network variables (shows
842
list of variables when run without arguments)
843
get_network <network id> <variable> = get network variables
844
save_config = save the current configuration
845
disconnect = disconnect and wait for reassociate command before connecting
846
scan = request new BSS scan
847
scan_results = get latest scan results
848
get_capability <eap/pairwise/group/key_mgmt/proto/auth_alg> = get capabilies
849
terminate = terminate wpa_supplicant
853
wpa_cli command line options
855
wpa_cli [-p<path to ctrl sockets>] [-i<ifname>] [-hvB] [-a<action file>] \
856
[-P<pid file>] [-g<global ctrl>] [command..]
857
-h = help (show this usage text)
858
-v = shown version information
859
-a = run in daemon mode executing the action file based on events from
861
-B = run a daemon in the background
862
default path: /var/run/wpa_supplicant
863
default interface: first interface found in socket path
866
Using wpa_cli to run external program on connect/disconnect
867
-----------------------------------------------------------
869
wpa_cli can used to run external programs whenever wpa_supplicant
870
connects or disconnects from a network. This can be used, e.g., to
871
update network configuration and/or trigget DHCP client to update IP
874
One wpa_cli process in "action" mode needs to be started for each
875
interface. For example, the following command starts wpa_cli for the
876
default ingterface (-i can be used to select the interface in case of
877
more than one interface being used at the same time):
879
wpa_cli -a/sbin/wpa_action.sh -B
881
The action file (-a option, /sbin/wpa_action.sh in this example) will
882
be executed whenever wpa_supplicant completes authentication (connect
883
event) or detects disconnection). The action script will be called
884
with two command line arguments: interface name and event (CONNECTED
885
or DISCONNECTED). If the action script needs to get more information
886
about the current network, it can use 'wpa_cli status' to query
887
wpa_supplicant for more information.
889
Following example can be used as a simple template for an action
897
if [ "$CMD" == "CONNECTED" ]; then
898
SSID=`wpa_cli -i$IFNAME status | grep ^ssid= | cut -f2- -d=`
899
# configure network, signal DHCP client, etc.
902
if [ "$CMD" == "DISCONNECTED" ]; then
903
# remove network configuration, if needed
908
Integrating with pcmcia-cs/cardmgr scripts
909
------------------------------------------
911
wpa_supplicant needs to be running when using a wireless network with
912
WPA. It can be started either from system startup scripts or from
913
pcmcia-cs/cardmgr scripts (when using PC Cards). WPA handshake must be
914
completed before data frames can be exchanged, so wpa_supplicant
915
should be started before DHCP client.
917
For example, following small changes to pcmcia-cs scripts can be used
918
to enable WPA support:
920
Add MODE="Managed" and WPA="y" to the network scheme in
921
/etc/pcmcia/wireless.opts.
923
Add the following block to the end of 'start' action handler in
924
/etc/pcmcia/wireless:
926
if [ "$WPA" = "y" -a -x /usr/local/bin/wpa_supplicant ]; then
927
/usr/local/bin/wpa_supplicant -B -c/etc/wpa_supplicant.conf \
931
Add the following block to the end of 'stop' action handler (may need
932
to be separated from other actions) in /etc/pcmcia/wireless:
934
if [ "$WPA" = "y" -a -x /usr/local/bin/wpa_supplicant ]; then
935
killall wpa_supplicant
938
This will make cardmgr start wpa_supplicant when the card is plugged
943
Dynamic interface add and operation without configuration files
944
---------------------------------------------------------------
946
wpa_supplicant can be started without any configuration files or
947
network interfaces. When used in this way, a global (i.e., per
948
wpa_supplicant process) control interface is used to add and remove
949
network interfaces. Each network interface can then be configured
950
through a per-network interface control interface. For example,
951
following commands show how to start wpa_supplicant without any
952
network interfaces and then add a network interface and configure a
955
# Start wpa_supplicant in the background
956
wpa_supplicant -g/var/run/wpa_supplicant-global -B
958
# Add a new interface (wlan0, no configuration file, driver=wext, and
959
# enable control interface)
960
wpa_cli -g/var/run/wpa_supplicant-global interface_add wlan0 \
961
"" wext /var/run/wpa_supplicant
963
# Configure a network using the newly added network interface:
964
wpa_cli -iwlan0 add_network
965
wpa_cli -iwlan0 set_network 0 ssid '"test"'
966
wpa_cli -iwlan0 set_network 0 key_mgmt WPA-PSK
967
wpa_cli -iwlan0 set_network 0 psk '"12345678"'
968
wpa_cli -iwlan0 set_network 0 pairwise TKIP
969
wpa_cli -iwlan0 set_network 0 group TKIP
970
wpa_cli -iwlan0 set_network 0 proto WPA
971
wpa_cli -iwlan0 enable_network 0
973
# At this point, the new network interface should start trying to associate
974
# with the WPA-PSK network using SSID test.
976
# Remove network interface
977
wpa_cli -g/var/run/wpa_supplicant-global interface_remove wlan0
983
To minimize the size of code that needs to be run with root privileges
984
(e.g., to control wireless interface operation), wpa_supplicant
985
supports optional privilege separation. If enabled, this separates the
986
privileged operations into a separate process (wpa_priv) while leaving
987
rest of the code (e.g., EAP authentication and WPA handshakes) into an
988
unprivileged process (wpa_supplicant) that can be run as non-root
989
user. Privilege separation restricts the effects of potential software
990
errors by containing the majority of the code in an unprivileged
991
process to avoid full system compromise.
993
Privilege separation is not enabled by default and it can be enabled
994
by adding CONFIG_PRIVSEP=y to the build configuration (.config). When
995
enabled, the privileged operations (driver wrapper and l2_packet) are
996
linked into a separate daemon program, wpa_priv. The unprivileged
997
program, wpa_supplicant, will be built with a special driver/l2_packet
998
wrappers that communicate with the privileged wpa_priv process to
999
perform the needed operations. wpa_priv can control what privileged
1002
wpa_priv needs to be run with network admin privileges (usually, root
1003
user). It opens a UNIX domain socket for each interface that is
1004
included on the command line; any other interface will be off limits
1005
for wpa_supplicant in this kind of configuration. After this,
1006
wpa_supplicant can be run as a non-root user (e.g., all standard users
1007
on a laptop or as a special non-privileged user account created just
1008
for this purpose to limit access to user files even further).
1011
Example configuration:
1012
- create user group for users that are allowed to use wpa_supplicant
1013
('wpapriv' in this example) and assign users that should be able to
1014
use wpa_supplicant into that group
1015
- create /var/run/wpa_priv directory for UNIX domain sockets and control
1016
user access by setting it accessible only for the wpapriv group:
1017
mkdir /var/run/wpa_priv
1018
chown root:wpapriv /var/run/wpa_priv
1019
chmod 0750 /var/run/wpa_priv
1020
- start wpa_priv as root (e.g., from system startup scripts) with the
1021
enabled interfaces configured on the command line:
1022
wpa_priv -B -P /var/run/wpa_priv.pid wext:ath0
1023
- run wpa_supplicant as non-root with a user that is in wpapriv group:
1024
wpa_supplicant -i ath0 -c wpa_supplicant.conf
1026
wpa_priv does not use the network interface before wpa_supplicant is
1027
started, so it is fine to include network interfaces that are not
1028
available at the time wpa_priv is started. As an alternative, wpa_priv
1029
can be started when an interface is added (hotplug/udev/etc. scripts).
1030
wpa_priv can control multiple interface with one process, but it is
1031
also possible to run multiple wpa_priv processes at the same time, if
added
removed
libeap/wpa_supplicant/README
