WPA Supplicant ============== Copyright (c) 2003-2004, Jouni Malinen All Rights Reserved. This program is dual-licensed under both the GPL version 2 and BSD licensed. Either license may be used at your option. Please note that some of the driver interface implementations (driver_*.c) may be licensed under a different license. License ------- GPL v2: This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License version 2 as published by the Free Software Foundation. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA (this copy of the license is in COPYING file) Alternatively, this software may be distributed under the terms of BSD license: Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. 3. Neither the name(s) of the above-listed copyright holder(s) nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. Features -------- Supported WPA/IEEE 802.11i features: - WPA-PSK ("WPA-Personal") - WPA with EAP (e.g., with RADIUS authentication server) ("WPA-Enterprise") Following authentication methods are supported with an integrate IEEE 802.1X Supplicant: * EAP-TLS * EAP-PEAP/MSCHAPv2 (both PEAPv0 and PEAPv1) * EAP-PEAP/TLS (both PEAPv0 and PEAPv1) * EAP-PEAP/GTC (both PEAPv0 and PEAPv1) * EAP-PEAP/OTP (both PEAPv0 and PEAPv1) * EAP-PEAP/MD5-Challenge (both PEAPv0 and PEAPv1) * EAP-TTLS/EAP-MD5-Challenge * EAP-TTLS/EAP-GTC * EAP-TTLS/EAP-OTP * EAP-TTLS/EAP-MSCHAPv2 * EAP-TTLS/EAP-TLS * EAP-TTLS/MSCHAPv2 * EAP-TTLS/MSCHAP * EAP-TTLS/PAP * EAP-TTLS/CHAP * EAP-SIM * LEAP (note: only with WEP keys, i.e., not for WPA; in addition, LEAP requires special support from the driver for IEEE 802.11 authentication) (following methods are supported, but since they do not generate keying material, they cannot be used with WPA or IEEE 802.1X WEP keying) * EAP-MD5-Challenge * EAP-MSCHAPv2 * EAP-GTC * EAP-OTP Alternatively, an external program, e.g., Xsupplicant, can be used for EAP authentication. - key management for CCMP, TKIP, WEP104, WEP40 - RSN/WPA2 (IEEE 802.11i) * pre-authentication * PMKSA caching Requirements ------------ Current hardware/software requirements: - Linux kernel 2.4.x or 2.6.x - Linux Wireless Extensions v15 or newer - drivers: Host AP driver for Prism2/2.5/3 (development snapshot/v0.2.x) in Managed mode ('iwconfig wlan0 mode managed'). Please note that station firmware version needs to be 1.7.0 or newer to work in WPA mode. Linuxant DriverLoader (http://www.linuxant.com/driverloader/) with Windows NDIS driver for your wlan card supporting WPA. Agere Systems Inc. Linux Driver (http://www.agere.com/support/drivers/) Please note that the driver interface file (driver_hermes.c) and hardware specific include files are not included in the wpa_supplicant distribution. You will need to copy these from the source package of the Agere driver. madwifi driver for cards based on Atheros chip set (ar521x) (http://sourceforge.net/projects/madwifi/) Please note that you will need to modify the wpa_supplicant Makefile to use correct path for madwifi driver root directory (CFLAGS += -I../madwifi/wpa line in Makefile). ATMEL AT76C5XXx driver for USB and PCMCIA cards (http://atmelwlandriver.sourceforge.net/). Linux ndiswrapper (http://ndiswrapper.sourceforge.net/) with Windows NDIS driver. In theory, any driver that supports Linux wireless extensions can be used with IEEE 802.1X (i.e., not WPA) when using ap_scan=0 option in configuration file. wpa_supplicant was designed to be portable for different drivers and operating systems. Hopefully, support for more wlan cards will be added in the future. See developer.txt for more information about the design of wpa_supplicant and porting to other drivers. One main goal is to add full WPA/WPA2 support to Linux wireless extensions to allow new drivers to be supported without having to implement new driver-specific interface code in wpa_supplicant. Optional libraries for layer2 packet processing: - libpcap (tested with 0.7.2, most relatively recent versions assumed to work, this is likely to be available with most distributions, http://tcpdump.org/) - libdnet (tested with v1.4, most versions assumed to work, http://libdnet.sourceforge.net/) These libraries are _not_ used in the default build. Instead, internal Linux specific implementation is used. libpcap/libdnet are more portable and they can be used by modifying Makefile (define USE_DNET_PCAP and link with these libraries). Optional libraries for EAP-TLS, EAP-PEAP, and EAP-TTLS: - openssl (tested with 0.9.7c and 0.9.7d, assumed to work with most relatively recent versions; this is likely to be available with most distributions, http://www.openssl.org/) This library is only needed when EAP-TLS, EAP-PEAP, or EAP-TTLS support is enabled. WPA-PSK mode does not require this or EAPOL/EAP implementation. A configuration file, .config, for compilation is needed to enable IEEE 802.1X/EAPOL and EAP methods. Note that EAP-MD5, EAP-GTC, EAP-OTP, and EAP-MSCHAPV2 cannot be used alone with WPA, so they should only be enabled if testing the EAPOL/EAP state machines. However, there can be used as inner authentication algorithms with EAP-PEAP and EAP-TTLS. See Building and installing section below for more detailed information about the wpa_supplicant build time configuration. WPA --- The original security mechanism of IEEE 802.11 standard was not designed to be strong and has proved to be insufficient for most networks that require some kind of security. Task group I (Security) of IEEE 802.11 working group (http://www.ieee802.org/11/) has worked to address the flaws of the base standard and has in practice completed its work in May 2004. The IEEE 802.11i amendment to the IEEE 802.11 standard was approved in June 2004 and this amendment is likely to be published in July 2004. Wi-Fi Alliance (http://www.wi-fi.org/) used a draft version of the IEEE 802.11i work (draft 3.0) to define a subset of the security enhancements that can be implemented with existing wlan hardware. This is called Wi-Fi Protected Access (WPA). This has now become a mandatory component of interoperability testing and certification done by Wi-Fi Alliance. Wi-Fi provides information about WPA at its web site (http://www.wi-fi.org/OpenSection/protected_access.asp). IEEE 802.11 standard defined wired equivalent privacy (WEP) algorithm for protecting wireless networks. WEP uses RC4 with 40-bit keys, 24-bit initialization vector (IV), and CRC32 to protect against packet forgery. All these choice have proved to be insufficient: key space is too small against current attacks, RC4 key scheduling is insufficient (beginning of the pseudorandom stream should be skipped), IV space is too small and IV reuse makes attacks easier, there is no replay protection, and non-keyed authentication does not protect against bit flipping packet data. WPA is an intermediate solution for the security issues. It uses temporal key integrity protocol (TKIP) to replace WEP. TKIP is a compromise on strong security and possibility to use existing hardware. It still uses RC4 for the encryption like WEP, but with per-packet RC4 keys. In addition, it implements replay protection, keyed packet authentication mechanism (Michael MIC). Keys can be managed using two different mechanisms. WPA can either use an external authentication server (e.g., RADIUS) and EAP just like IEEE 802.1X is using or pre-shared keys without need for additional servers. Wi-Fi calls these "WPA-Enterprise" and "WPA-Personal", respectively. Both mechanisms will generate a master session key for the Authenticator (AP) and Supplicant (client station). WPA implements a new key handshake (4-Way Handshake and Group Key Handshake) for generating and exchanging data encryption keys between the Authenticator and Supplicant. This handshake is also used to verify that both Authenticator and Supplicant know the master session key. These handshakes are identical regardless of the selected key management mechanism (only the method for generating master session key changes). IEEE 802.11i / WPA2 ------------------- The design for parts of IEEE 802.11i that were not included in WPA has finished (May 2004) and this amendment to IEEE 802.11 was approved in June 2004. Wi-Fi Alliance is using the final IEEE 802.11i as a new version of WPA called WPA2. This includes, e.g., support for more robust encryption algorithm (CCMP: AES in Counter mode with CBC-MAC) to replace TKIP and optimizations for handoff (reduced number of messages in initial key handshake, pre-authentication, key caching). Some wireless LAN vendors are already providing support for CCMP in their WPA products. There is no "official" interoperability certification for CCMP and/or mixed modes using both TKIP and CCMP, so some interoperability issues can be expected even though many combinations seem to be working with equipment from different vendors. Certification for WPA2 is likely to start during the second half of 2004. wpa_supplicant -------------- wpa_supplicant is an implementation of the WPA Supplicant component, i.e., the part that runs in the client stations. It implements WPA key negotiation with a WPA Authenticator and EAP authentication with Authentication Server. In addition, it controls the roaming and IEEE 802.11 authentication/association of the wlan driver. wpa_supplicant is designed to be a "daemon" program that runs in the background and acts as the backend component controlling the wireless connection. wpa_supplicant supports separate frontend programs and an example text-based frontend, wpa_cli, is included with wpa_supplicant. Following steps are used when associating with an AP using WPA: - wpa_supplicant requests the kernel driver to scan neighboring BSSes - wpa_supplicant selects a BSS based on its configuration - wpa_supplicant requests the kernel driver to associate with the chosen BSS - If WPA-EAP: integrated IEEE 802.1X Supplicant or external Xsupplicant completes EAP authentication with the authentication server (proxied by the Authenticator in the AP) - If WPA-EAP: master key is received from the IEEE 802.1X Supplicant - If WPA-PSK: wpa_supplicant uses PSK as the master session key - wpa_supplicant completes WPA 4-Way Handshake and Group Key Handshake with the Authenticator (AP) - wpa_supplicant configures encryption keys for unicast and broadcast - normal data packets can be transmitted and received Building and installing ----------------------- In order to be able to build wpa_supplicant, you will first need to select which parts of it will be included. This is done by creating a build time configuration file, .config, in the wpa_supplicant root directory. Configuration options are text lines using following format: CONFIG_