1214503Srpaulohostapd - user space IEEE 802.11 AP and IEEE 802.1X/WPA/WPA2/EAP 2214503Srpaulo Authenticator and RADIUS authentication server 3214503Srpaulo================================================================ 4214503Srpaulo 5281806SrpauloCopyright (c) 2002-2015, Jouni Malinen <j@w1.fi> and contributors 6214503SrpauloAll Rights Reserved. 7214503Srpaulo 8252726SrpauloThis program is licensed under the BSD license (the one with 9252726Srpauloadvertisement clause removed). 10214503Srpaulo 11252726SrpauloIf you are submitting changes to the project, please see CONTRIBUTIONS 12252726Srpaulofile for more instructions. 13214503Srpaulo 14214503Srpaulo 15252726Srpaulo 16214503SrpauloLicense 17214503Srpaulo------- 18214503Srpaulo 19252726SrpauloThis software may be distributed, used, and modified under the terms of 20252726SrpauloBSD license: 21214503Srpaulo 22214503SrpauloRedistribution and use in source and binary forms, with or without 23214503Srpaulomodification, are permitted provided that the following conditions are 24214503Srpaulomet: 25214503Srpaulo 26214503Srpaulo1. Redistributions of source code must retain the above copyright 27214503Srpaulo notice, this list of conditions and the following disclaimer. 28214503Srpaulo 29214503Srpaulo2. Redistributions in binary form must reproduce the above copyright 30214503Srpaulo notice, this list of conditions and the following disclaimer in the 31214503Srpaulo documentation and/or other materials provided with the distribution. 32214503Srpaulo 33214503Srpaulo3. Neither the name(s) of the above-listed copyright holder(s) nor the 34214503Srpaulo names of its contributors may be used to endorse or promote products 35214503Srpaulo derived from this software without specific prior written permission. 36214503Srpaulo 37214503SrpauloTHIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 38214503Srpaulo"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 39214503SrpauloLIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 40214503SrpauloA PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 41214503SrpauloOWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 42214503SrpauloSPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 43214503SrpauloLIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 44214503SrpauloDATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 45214503SrpauloTHEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 46214503Srpaulo(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 47214503SrpauloOF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 48214503Srpaulo 49214503Srpaulo 50214503Srpaulo 51214503SrpauloIntroduction 52214503Srpaulo============ 53214503Srpaulo 54214503SrpauloOriginally, hostapd was an optional user space component for Host AP 55214503Srpaulodriver. It adds more features to the basic IEEE 802.11 management 56214503Srpauloincluded in the kernel driver: using external RADIUS authentication 57214503Srpauloserver for MAC address based access control, IEEE 802.1X Authenticator 58214503Srpauloand dynamic WEP keying, RADIUS accounting, WPA/WPA2 (IEEE 802.11i/RSN) 59214503SrpauloAuthenticator and dynamic TKIP/CCMP keying. 60214503Srpaulo 61214503SrpauloThe current version includes support for other drivers, an integrated 62214503SrpauloEAP server (i.e., allow full authentication without requiring 63214503Srpauloan external RADIUS authentication server), and RADIUS authentication 64214503Srpauloserver for EAP authentication. 65214503Srpaulo 66214503Srpaulo 67214503SrpauloRequirements 68214503Srpaulo------------ 69214503Srpaulo 70214503SrpauloCurrent hardware/software requirements: 71214503Srpaulo- drivers: 72214503Srpaulo Host AP driver for Prism2/2.5/3. 73214503Srpaulo (http://hostap.epitest.fi/) 74214503Srpaulo Please note that station firmware version needs to be 1.7.0 or newer 75214503Srpaulo to work in WPA mode. 76214503Srpaulo 77214503Srpaulo mac80211-based drivers that support AP mode (with driver=nl80211). 78214503Srpaulo This includes drivers for Atheros (ath9k) and Broadcom (b43) 79214503Srpaulo chipsets. 80214503Srpaulo 81214503Srpaulo Any wired Ethernet driver for wired IEEE 802.1X authentication 82214503Srpaulo (experimental code) 83214503Srpaulo 84214503Srpaulo FreeBSD -current (with some kernel mods that have not yet been 85214503Srpaulo committed when hostapd v0.3.0 was released) 86214503Srpaulo BSD net80211 layer (e.g., Atheros driver) 87214503Srpaulo 88214503Srpaulo 89214503SrpauloBuild configuration 90214503Srpaulo------------------- 91214503Srpaulo 92214503SrpauloIn order to be able to build hostapd, you will need to create a build 93214503Srpaulotime configuration file, .config that selects which optional 94214503Srpaulocomponents are included. See defconfig file for example configuration 95214503Srpauloand list of available options. 96214503Srpaulo 97214503Srpaulo 98214503Srpaulo 99214503SrpauloIEEE 802.1X 100214503Srpaulo=========== 101214503Srpaulo 102214503SrpauloIEEE Std 802.1X-2001 is a standard for port-based network access 103214503Srpaulocontrol. In case of IEEE 802.11 networks, a "virtual port" is used 104214503Srpaulobetween each associated station and the AP. IEEE 802.11 specifies 105214503Srpaulominimal authentication mechanism for stations, whereas IEEE 802.1X 106214503Srpaulointroduces a extensible mechanism for authenticating and authorizing 107214503Srpaulousers. 108214503Srpaulo 109214503SrpauloIEEE 802.1X uses elements called Supplicant, Authenticator, Port 110214503SrpauloAccess Entity, and Authentication Server. Supplicant is a component in 111214503Srpauloa station and it performs the authentication with the Authentication 112214503SrpauloServer. An access point includes an Authenticator that relays the packets 113214503Srpaulobetween a Supplicant and an Authentication Server. In addition, it has a 114214503SrpauloPort Access Entity (PAE) with Authenticator functionality for 115214503Srpaulocontrolling the virtual port authorization, i.e., whether to accept 116214503Srpaulopackets from or to the station. 117214503Srpaulo 118214503SrpauloIEEE 802.1X uses Extensible Authentication Protocol (EAP). The frames 119214503Srpaulobetween a Supplicant and an Authenticator are sent using EAP over LAN 120214503Srpaulo(EAPOL) and the Authenticator relays these frames to the Authentication 121214503SrpauloServer (and similarly, relays the messages from the Authentication 122214503SrpauloServer to the Supplicant). The Authentication Server can be colocated with the 123214503SrpauloAuthenticator, in which case there is no need for additional protocol 124214503Srpaulofor EAP frame transmission. However, a more common configuration is to 125214503Srpaulouse an external Authentication Server and encapsulate EAP frame in the 126214503Srpauloframes used by that server. RADIUS is suitable for this, but IEEE 127214503Srpaulo802.1X would also allow other mechanisms. 128214503Srpaulo 129214503SrpauloHost AP driver includes PAE functionality in the kernel driver. It 130214503Srpaulois a relatively simple mechanism for denying normal frames going to 131214503Srpauloor coming from an unauthorized port. PAE allows IEEE 802.1X related 132214503Srpauloframes to be passed between the Supplicant and the Authenticator even 133214503Srpauloon an unauthorized port. 134214503Srpaulo 135214503SrpauloUser space daemon, hostapd, includes Authenticator functionality. It 136214503Srpauloreceives 802.1X (EAPOL) frames from the Supplicant using the wlan#ap 137214503Srpaulodevice that is also used with IEEE 802.11 management frames. The 138214503Srpauloframes to the Supplicant are sent using the same device. 139214503Srpaulo 140214503SrpauloThe normal configuration of the Authenticator would use an external 141214503SrpauloAuthentication Server. hostapd supports RADIUS encapsulation of EAP 142214503Srpaulopackets, so the Authentication Server should be a RADIUS server, like 143214503SrpauloFreeRADIUS (http://www.freeradius.org/). The Authenticator in hostapd 144214503Srpaulorelays the frames between the Supplicant and the Authentication 145214503SrpauloServer. It also controls the PAE functionality in the kernel driver by 146214503Srpaulocontrolling virtual port authorization, i.e., station-AP 147214503Srpauloconnection, based on the IEEE 802.1X state. 148214503Srpaulo 149214503SrpauloWhen a station would like to use the services of an access point, it 150214503Srpaulowill first perform IEEE 802.11 authentication. This is normally done 151214503Srpaulowith open systems authentication, so there is no security. After 152214503Srpaulothis, IEEE 802.11 association is performed. If IEEE 802.1X is 153214503Srpauloconfigured to be used, the virtual port for the station is set in 154214503SrpauloUnauthorized state and only IEEE 802.1X frames are accepted at this 155214503Srpaulopoint. The Authenticator will then ask the Supplicant to authenticate 156214503Srpaulowith the Authentication Server. After this is completed successfully, 157214503Srpaulothe virtual port is set to Authorized state and frames from and to the 158214503Srpaulostation are accepted. 159214503Srpaulo 160214503SrpauloHost AP configuration for IEEE 802.1X 161214503Srpaulo------------------------------------- 162214503Srpaulo 163214503SrpauloThe user space daemon has its own configuration file that can be used to 164214503Srpaulodefine AP options. Distribution package contains an example 165214503Srpauloconfiguration file (hostapd/hostapd.conf) that can be used as a basis 166214503Srpaulofor configuration. It includes examples of all supported configuration 167214503Srpaulooptions and short description of each option. hostapd should be started 168214503Srpaulowith full path to the configuration file as the command line argument, 169214503Srpauloe.g., './hostapd /etc/hostapd.conf'. If you have more that one wireless 170214503SrpauloLAN card, you can use one hostapd process for multiple interfaces by 171214503Srpaulogiving a list of configuration files (one per interface) in the command 172214503Srpauloline. 173214503Srpaulo 174214503Srpaulohostapd includes a minimal co-located IEEE 802.1X server which can be 175214503Srpauloused to test IEEE 802.1X authentication. However, it should not be 176214503Srpauloused in normal use since it does not provide any security. This can be 177214503Srpauloconfigured by setting ieee8021x and minimal_eap options in the 178214503Srpauloconfiguration file. 179214503Srpaulo 180214503SrpauloAn external Authentication Server (RADIUS) is configured with 181214503Srpauloauth_server_{addr,port,shared_secret} options. In addition, 182214503Srpauloieee8021x and own_ip_addr must be set for this mode. With such 183214503Srpauloconfiguration, the co-located Authentication Server is not used and EAP 184214503Srpauloframes will be relayed using EAPOL between the Supplicant and the 185214503SrpauloAuthenticator and RADIUS encapsulation between the Authenticator and 186214503Srpaulothe Authentication Server. Other than this, the functionality is similar 187214503Srpauloto the case with the co-located Authentication Server. 188214503Srpaulo 189214503SrpauloAuthentication Server and Supplicant 190214503Srpaulo------------------------------------ 191214503Srpaulo 192214503SrpauloAny RADIUS server supporting EAP should be usable as an IEEE 802.1X 193214503SrpauloAuthentication Server with hostapd Authenticator. FreeRADIUS 194214503Srpaulo(http://www.freeradius.org/) has been successfully tested with hostapd 195214503SrpauloAuthenticator and both Xsupplicant (http://www.open1x.org) and Windows 196214503SrpauloXP Supplicants. EAP/TLS was used with Xsupplicant and 197214503SrpauloEAP/MD5-Challenge with Windows XP. 198214503Srpaulo 199214503Srpaulohttp://www.missl.cs.umd.edu/wireless/eaptls/ has useful information 200214503Srpauloabout using EAP/TLS with FreeRADIUS and Xsupplicant (just replace 201214503SrpauloCisco access point with Host AP driver, hostapd daemon, and a Prism2 202214503Srpaulocard ;-). http://www.freeradius.org/doc/EAP-MD5.html has information 203214503Srpauloabout using EAP/MD5 with FreeRADIUS, including instructions for WinXP 204214503Srpauloconfiguration. http://www.denobula.com/EAPTLS.pdf has a HOWTO on 205214503SrpauloEAP/TLS use with WinXP Supplicant. 206214503Srpaulo 207214503SrpauloAutomatic WEP key configuration 208214503Srpaulo------------------------------- 209214503Srpaulo 210214503SrpauloEAP/TLS generates a session key that can be used to send WEP keys from 211214503Srpauloan AP to authenticated stations. The Authenticator in hostapd can be 212214503Srpauloconfigured to automatically select a random default/broadcast key 213214503Srpaulo(shared by all authenticated stations) with wep_key_len_broadcast 214214503Srpaulooption (5 for 40-bit WEP or 13 for 104-bit WEP). In addition, 215214503Srpaulowep_key_len_unicast option can be used to configure individual unicast 216214503Srpaulokeys for stations. This requires support for individual keys in the 217214503Srpaulostation driver. 218214503Srpaulo 219214503SrpauloWEP keys can be automatically updated by configuring rekeying. This 220214503Srpaulowill improve security of the network since same WEP key will only be 221214503Srpauloused for a limited period of time. wep_rekey_period option sets the 222214503Srpaulointerval for rekeying in seconds. 223214503Srpaulo 224214503Srpaulo 225214503SrpauloWPA/WPA2 226214503Srpaulo======== 227214503Srpaulo 228214503SrpauloFeatures 229214503Srpaulo-------- 230214503Srpaulo 231214503SrpauloSupported WPA/IEEE 802.11i features: 232214503Srpaulo- WPA-PSK ("WPA-Personal") 233214503Srpaulo- WPA with EAP (e.g., with RADIUS authentication server) ("WPA-Enterprise") 234214503Srpaulo- key management for CCMP, TKIP, WEP104, WEP40 235214503Srpaulo- RSN/WPA2 (IEEE 802.11i), including PMKSA caching and pre-authentication 236214503Srpaulo 237214503SrpauloWPA 238214503Srpaulo--- 239214503Srpaulo 240214503SrpauloThe original security mechanism of IEEE 802.11 standard was not 241214503Srpaulodesigned to be strong and has proved to be insufficient for most 242214503Srpaulonetworks that require some kind of security. Task group I (Security) 243214503Srpauloof IEEE 802.11 working group (http://www.ieee802.org/11/) has worked 244214503Srpauloto address the flaws of the base standard and has in practice 245214503Srpaulocompleted its work in May 2004. The IEEE 802.11i amendment to the IEEE 246214503Srpaulo802.11 standard was approved in June 2004 and this amendment is likely 247214503Srpauloto be published in July 2004. 248214503Srpaulo 249214503SrpauloWi-Fi Alliance (http://www.wi-fi.org/) used a draft version of the 250214503SrpauloIEEE 802.11i work (draft 3.0) to define a subset of the security 251214503Srpauloenhancements that can be implemented with existing wlan hardware. This 252214503Srpaulois called Wi-Fi Protected Access<TM> (WPA). This has now become a 253214503Srpaulomandatory component of interoperability testing and certification done 254214503Srpauloby Wi-Fi Alliance. Wi-Fi provides information about WPA at its web 255214503Srpaulosite (http://www.wi-fi.org/OpenSection/protected_access.asp). 256214503Srpaulo 257214503SrpauloIEEE 802.11 standard defined wired equivalent privacy (WEP) algorithm 258214503Srpaulofor protecting wireless networks. WEP uses RC4 with 40-bit keys, 259214503Srpaulo24-bit initialization vector (IV), and CRC32 to protect against packet 260214503Srpauloforgery. All these choices have proven to be insufficient: key space is 261214503Srpaulotoo small against current attacks, RC4 key scheduling is insufficient 262214503Srpaulo(beginning of the pseudorandom stream should be skipped), IV space is 263214503Srpaulotoo small and IV reuse makes attacks easier, there is no replay 264214503Srpauloprotection, and non-keyed authentication does not protect against bit 265214503Srpauloflipping packet data. 266214503Srpaulo 267214503SrpauloWPA is an intermediate solution for the security issues. It uses 268214503SrpauloTemporal Key Integrity Protocol (TKIP) to replace WEP. TKIP is a 269214503Srpaulocompromise on strong security and possibility to use existing 270214503Srpaulohardware. It still uses RC4 for the encryption like WEP, but with 271214503Srpauloper-packet RC4 keys. In addition, it implements replay protection, 272214503Srpaulokeyed packet authentication mechanism (Michael MIC). 273214503Srpaulo 274214503SrpauloKeys can be managed using two different mechanisms. WPA can either use 275214503Srpauloan external authentication server (e.g., RADIUS) and EAP just like 276214503SrpauloIEEE 802.1X is using or pre-shared keys without need for additional 277214503Srpauloservers. Wi-Fi calls these "WPA-Enterprise" and "WPA-Personal", 278214503Srpaulorespectively. Both mechanisms will generate a master session key for 279214503Srpaulothe Authenticator (AP) and Supplicant (client station). 280214503Srpaulo 281214503SrpauloWPA implements a new key handshake (4-Way Handshake and Group Key 282214503SrpauloHandshake) for generating and exchanging data encryption keys between 283214503Srpaulothe Authenticator and Supplicant. This handshake is also used to 284214503Srpauloverify that both Authenticator and Supplicant know the master session 285214503Srpaulokey. These handshakes are identical regardless of the selected key 286214503Srpaulomanagement mechanism (only the method for generating master session 287214503Srpaulokey changes). 288214503Srpaulo 289214503Srpaulo 290214503SrpauloIEEE 802.11i / WPA2 291214503Srpaulo------------------- 292214503Srpaulo 293214503SrpauloThe design for parts of IEEE 802.11i that were not included in WPA has 294214503Srpaulofinished (May 2004) and this amendment to IEEE 802.11 was approved in 295214503SrpauloJune 2004. Wi-Fi Alliance is using the final IEEE 802.11i as a new 296214503Srpauloversion of WPA called WPA2. This includes, e.g., support for more 297214503Srpaulorobust encryption algorithm (CCMP: AES in Counter mode with CBC-MAC) 298214503Srpauloto replace TKIP and optimizations for handoff (reduced number of 299214503Srpaulomessages in initial key handshake, pre-authentication, and PMKSA caching). 300214503Srpaulo 301214503SrpauloSome wireless LAN vendors are already providing support for CCMP in 302214503Srpaulotheir WPA products. There is no "official" interoperability 303214503Srpaulocertification for CCMP and/or mixed modes using both TKIP and CCMP, so 304214503Srpaulosome interoperability issues can be expected even though many 305214503Srpaulocombinations seem to be working with equipment from different vendors. 306214503SrpauloTesting for WPA2 is likely to start during the second half of 2004. 307214503Srpaulo 308214503Srpaulohostapd configuration for WPA/WPA2 309214503Srpaulo---------------------------------- 310214503Srpaulo 311214503SrpauloTODO 312214503Srpaulo 313214503Srpaulo# Enable WPA. Setting this variable configures the AP to require WPA (either 314214503Srpaulo# WPA-PSK or WPA-RADIUS/EAP based on other configuration). For WPA-PSK, either 315214503Srpaulo# wpa_psk or wpa_passphrase must be set and wpa_key_mgmt must include WPA-PSK. 316214503Srpaulo# For WPA-RADIUS/EAP, ieee8021x must be set (but without dynamic WEP keys), 317214503Srpaulo# RADIUS authentication server must be configured, and WPA-EAP must be included 318214503Srpaulo# in wpa_key_mgmt. 319214503Srpaulo# This field is a bit field that can be used to enable WPA (IEEE 802.11i/D3.0) 320214503Srpaulo# and/or WPA2 (full IEEE 802.11i/RSN): 321214503Srpaulo# bit0 = WPA 322214503Srpaulo# bit1 = IEEE 802.11i/RSN (WPA2) 323214503Srpaulo#wpa=1 324214503Srpaulo 325214503Srpaulo# WPA pre-shared keys for WPA-PSK. This can be either entered as a 256-bit 326214503Srpaulo# secret in hex format (64 hex digits), wpa_psk, or as an ASCII passphrase 327214503Srpaulo# (8..63 characters) that will be converted to PSK. This conversion uses SSID 328214503Srpaulo# so the PSK changes when ASCII passphrase is used and the SSID is changed. 329214503Srpaulo#wpa_psk=0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef 330214503Srpaulo#wpa_passphrase=secret passphrase 331214503Srpaulo 332214503Srpaulo# Set of accepted key management algorithms (WPA-PSK, WPA-EAP, or both). The 333214503Srpaulo# entries are separated with a space. 334214503Srpaulo#wpa_key_mgmt=WPA-PSK WPA-EAP 335214503Srpaulo 336214503Srpaulo# Set of accepted cipher suites (encryption algorithms) for pairwise keys 337214503Srpaulo# (unicast packets). This is a space separated list of algorithms: 338214503Srpaulo# CCMP = AES in Counter mode with CBC-MAC [RFC 3610, IEEE 802.11i] 339214503Srpaulo# TKIP = Temporal Key Integrity Protocol [IEEE 802.11i] 340214503Srpaulo# Group cipher suite (encryption algorithm for broadcast and multicast frames) 341214503Srpaulo# is automatically selected based on this configuration. If only CCMP is 342214503Srpaulo# allowed as the pairwise cipher, group cipher will also be CCMP. Otherwise, 343214503Srpaulo# TKIP will be used as the group cipher. 344214503Srpaulo#wpa_pairwise=TKIP CCMP 345214503Srpaulo 346214503Srpaulo# Time interval for rekeying GTK (broadcast/multicast encryption keys) in 347214503Srpaulo# seconds. 348214503Srpaulo#wpa_group_rekey=600 349214503Srpaulo 350214503Srpaulo# Time interval for rekeying GMK (master key used internally to generate GTKs 351214503Srpaulo# (in seconds). 352214503Srpaulo#wpa_gmk_rekey=86400 353214503Srpaulo 354214503Srpaulo# Enable IEEE 802.11i/RSN/WPA2 pre-authentication. This is used to speed up 355214503Srpaulo# roaming be pre-authenticating IEEE 802.1X/EAP part of the full RSN 356214503Srpaulo# authentication and key handshake before actually associating with a new AP. 357214503Srpaulo#rsn_preauth=1 358214503Srpaulo# 359214503Srpaulo# Space separated list of interfaces from which pre-authentication frames are 360214503Srpaulo# accepted (e.g., 'eth0' or 'eth0 wlan0wds0'. This list should include all 361214503Srpaulo# interface that are used for connections to other APs. This could include 362214503Srpaulo# wired interfaces and WDS links. The normal wireless data interface towards 363214503Srpaulo# associated stations (e.g., wlan0) should not be added, since 364214503Srpaulo# pre-authentication is only used with APs other than the currently associated 365214503Srpaulo# one. 366214503Srpaulo#rsn_preauth_interfaces=eth0 367