![]() |
Welcome to ftp.vim.org,
Hosted by ftp.nluug.nl Current directory: /pub/os/BSD/NetBSD/NetBSD-release-9/src/external/bsd/wpa/dist/wpa_supplicant/ |
Contents of README:wpa_supplicant ============== Copyright (c) 2003-2019, Jouni Malinen <j@w1.fi> and contributors All Rights Reserved. This program is licensed under the BSD license (the one with advertisement clause removed). If you are submitting changes to the project, please see CONTRIBUTIONS file for more instructions. License ------- This software may be distributed, used, and modified 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 * EAP-AKA * EAP-AKA' * EAP-PSK * EAP-PAX * EAP-SAKE * EAP-IKEv2 * EAP-GPSK * EAP-pwd * LEAP (note: 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 - key management for CCMP, TKIP, WEP104, WEP40 - RSN/WPA2 (IEEE 802.11i) * pre-authentication * PMKSA caching Supported TLS/crypto libraries: - OpenSSL (default) - GnuTLS Internal TLS/crypto implementation (optional): - can be used in place of an external TLS/crypto library - TLSv1 - X.509 certificate processing - PKCS #1 - ASN.1 - RSA - bignum - minimal size (ca. 50 kB binary, parts of which are already needed for WPA; TLSv1/X.509/ASN.1/RSA/bignum parts are about 25 kB on x86) Requirements ------------ Current hardware/software requirements: - Linux kernel 2.4.x or 2.6.x with Linux Wireless Extensions v15 or newer - FreeBSD 6-CURRENT - NetBSD-current - Microsoft Windows with WinPcap (at least WinXP, may work with other versions) - drivers: Linux drivers that support cfg80211/nl80211. Even though there are number of driver specific interface included in wpa_supplicant, please note that Linux drivers are moving to use generic wireless configuration interface driver_nl80211 (-Dnl80211 on wpa_supplicant command line) should be the default option to start with before falling back to driver specific interface. Linux drivers that support WPA/WPA2 configuration with the generic Linux wireless extensions (WE-18 or newer). Obsoleted by nl80211. 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. Wired Ethernet drivers (with ap_scan=0) BSD net80211 layer (e.g., Atheros driver) At the moment, this is for FreeBSD 6-CURRENT branch and NetBSD-current. Windows NDIS The current Windows port requires WinPcap (http://winpcap.polito.it/). See README-Windows.txt for more information. wpa_supplicant was designed to be portable for different drivers and operating systems. Hopefully, support for more wlan cards and OSes will be added in the future. See developer's documentation (http://hostap.epitest.fi/wpa_supplicant/devel/) 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 Linux build. Instead, internal Linux specific implementation is used. libpcap/libdnet are more portable and they can be used by adding CONFIG_L2_PACKET=pcap into .config. They may also be selected automatically for other operating systems. In case of Windows builds, WinPcap is used by default (CONFIG_L2_PACKET=winpcap). Optional libraries for EAP-TLS, EAP-PEAP, and EAP-TTLS: - OpenSSL (tested with 1.0.1 and 1.0.2 versions; assumed to work with most relatively recent versions; this is likely to be available with most distributions, http://www.openssl.org/) - GnuTLS - internal TLSv1 implementation One of these libraries is needed when EAP-TLS, EAP-PEAP, EAP-TTLS, or EAP-FAST 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 proven 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 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<TM> (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 choices have proven 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, and PMKSA caching). 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 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_<option>=y. Lines starting with # are considered comments and are ignored. See defconfig file for an example configuration and a list of available options and additional notes. The build time configuration can be used to select only the needed features and limit the binary size and requirements for external libraries. The main configuration parts are the selection of which driver interfaces (e.g., nl80211, wext, ..) and which authentication methods (e.g., EAP-TLS, EAP-PEAP, ..) are included. Following build time configuration options are used to control IEEE 802.1X/EAPOL and EAP state machines and all EAP methods. Including TLS, PEAP, or TTLS will require linking wpa_supplicant with OpenSSL library for TLS implementation. Alternatively, GnuTLS or the internal TLSv1 implementation can be used for TLS functionality. CONFIG_IEEE8021X_EAPOL=y CONFIG_EAP_MD5=y CONFIG_EAP_MSCHAPV2=y CONFIG_EAP_TLS=y CONFIG_EAP_PEAP=y CONFIG_EAP_TTLS=y CONFIG_EAP_GTC=y CONFIG_EAP_OTP=y CONFIG_EAP_SIM=y CONFIG_EAP_AKA=y CONFIG_EAP_AKA_PRIME=y CONFIG_EAP_PSK=y CONFIG_EAP_SAKE=y CONFIG_EAP_GPSK=y CONFIG_EAP_PAX=y CONFIG_EAP_LEAP=y CONFIG_EAP_IKEV2=y CONFIG_EAP_PWD=y Following option can be used to include GSM SIM/USIM interface for GSM/UMTS authentication algorithm (for EAP-SIM/EAP-AKA/EAP-AKA'). This requires pcsc-lite (http://www.linuxnet.com/) for smart card access. CONFIG_PCSC=y Following options can be added to .config to select which driver interfaces are included. CONFIG_DRIVER_NL80211=y CONFIG_DRIVER_WEXT=y CONFIG_DRIVER_BSD=y CONFIG_DRIVER_NDIS=y Following example includes some more features and driver interfaces that are included in the wpa_supplicant package: CONFIG_DRIVER_NL80211=y CONFIG_DRIVER_WEXT=y CONFIG_DRIVER_BSD=y CONFIG_DRIVER_NDIS=y CONFIG_IEEE8021X_EAPOL=y CONFIG_EAP_MD5=y CONFIG_EAP_MSCHAPV2=y CONFIG_EAP_TLS=y CONFIG_EAP_PEAP=y CONFIG_EAP_TTLS=y CONFIG_EAP_GTC=y CONFIG_EAP_OTP=y CONFIG_EAP_SIM=y CONFIG_EAP_AKA=y CONFIG_EAP_PSK=y CONFIG_EAP_SAKE=y CONFIG_EAP_GPSK=y CONFIG_EAP_PAX=y CONFIG_EAP_LEAP=y CONFIG_EAP_IKEV2=y CONFIG_PCSC=y EAP-PEAP and EAP-TTLS will automatically include configured EAP methods (MD5, OTP, GTC, MSCHAPV2) for inner authentication selection. After you have created a configuration file, you can build wpa_supplicant and wpa_cli with 'make' command. You may then install the binaries to a suitable system directory, e.g., /usr/local/bin. Example commands: # build wpa_supplicant and wpa_cli make # install binaries (this may need root privileges) cp wpa_cli wpa_supplicant /usr/local/bin You will need to make a configuration file, e.g., /etc/wpa_supplicant.conf, with network configuration for the networks you are going to use. Configuration file section below includes explanation fo the configuration file format and includes various examples. Once the configuration is ready, you can test whether the configuration work by first running wpa_supplicant with following command to start it on foreground with debugging enabled: wpa_supplicant -iwlan0 -c/etc/wpa_supplicant.conf -d Assuming everything goes fine, you can start using following command to start wpa_supplicant on background without debugging: wpa_supplicant -iwlan0 -c/etc/wpa_supplicant.conf -B Please note that if you included more than one driver interface in the build time configuration (.config), you may need to specify which interface to use by including -D<driver name> option on the command line. See following section for more details on command line options for wpa_supplicant. Command line options -------------------- usage: wpa_supplicant [-BddfhKLqqtuvW] [-P<pid file>] [-g<global ctrl>] \ [-G<group>] \ -i<ifname> -c<config file> [-C<ctrl>] [-D<driver>] [-p<driver_param>] \ [-b<br_ifname> [-MN -i<ifname> -c<conf> [-C<ctrl>] [-D<driver>] \ [-p<driver_param>] [-b<br_ifname>] [-m<P2P Device config file>] ... options: -b = optional bridge interface name -B = run daemon in the background -c = Configuration file -C = ctrl_interface parameter (only used if -c is not) -i = interface name -d = increase debugging verbosity (-dd even more) -D = driver name (can be multiple drivers: nl80211,wext) -f = Log output to default log location (normally /tmp) -g = global ctrl_interface -G = global ctrl_interface group -K = include keys (passwords, etc.) in debug output -t = include timestamp in debug messages -h = show this help text -L = show license (BSD) -p = driver parameters -P = PID file -q = decrease debugging verbosity (-qq even less) -u = enable DBus control interface -v = show version -W = wait for a control interface monitor before starting -M = start describing matching interface -N = start describing new interface -m = Configuration file for the P2P Device drivers: nl80211 = Linux nl80211/cfg80211 wext = Linux wireless extensions (generic) wired = wpa_supplicant wired Ethernet driver roboswitch = wpa_supplicant Broadcom switch driver bsd = BSD 802.11 support (Atheros, etc.) ndis = Windows NDIS driver In most common cases, wpa_supplicant is started with wpa_supplicant -B -c/etc/wpa_supplicant.conf -iwlan0 This makes the process fork into background. The easiest way to debug problems, and to get debug log for bug reports, is to start wpa_supplicant on foreground with debugging enabled: wpa_supplicant -c/etc/wpa_supplicant.conf -iwlan0 -d If the specific driver wrapper is not known beforehand, it is possible to specify multiple comma separated driver wrappers on the command line. wpa_supplicant will use the first driver wrapper that is able to initialize the interface. wpa_supplicant -Dnl80211,wext -c/etc/wpa_supplicant.conf -iwlan0 wpa_supplicant can control multiple interfaces (radios) either by running one process for each interface separately or by running just one process and list of options at command line. Each interface is separated with -N argument. As an example, following command would start wpa_supplicant for two interfaces: wpa_supplicant \ -c wpa1.conf -i wlan0 -D nl80211 -N \ -c wpa2.conf -i wlan1 -D wext If the interfaces on which wpa_supplicant is to run are not known or do not exist, wpa_supplicant can match an interface when it arrives. Each matched interface is separated with -M argument and the -i argument now allows for pattern matching. As an example, the following command would start wpa_supplicant for a specific wired interface called lan0, any interface starting with wlan and lastly any other interface. Each match has its own configuration file, and for the wired interface a specific driver has also been given. wpa_supplicant \ -M -c wpa_wired.conf -ilan0 -D wired \ -M -c wpa1.conf -iwlan* \ -M -c wpa2.conf If the interface is added in a Linux bridge (e.g., br0), the bridge interface needs to be configured to wpa_supplicant in addition to the main interface: wpa_supplicant -cw.conf -Dnl80211 -iwlan0 -bbr0 Configuration file ------------------ wpa_supplicant is configured using a text file that lists all accepted networks and security policies, including pre-shared keys. See example configuration file, wpa_supplicant.conf, for detailed information about the configuration format and supported fields. Changes to configuration file can be reloaded be sending SIGHUP signal to wpa_supplicant ('killall -HUP wpa_supplicant'). Similarly, reloading can be triggered with 'wpa_cli reconfigure' command. Configuration file can include one or more network blocks, e.g., one for each used SSID. wpa_supplicant will automatically select the best network based on the order of network blocks in the configuration file, network security level (WPA/WPA2 is preferred), and signal strength. Example configuration files for some common configurations: 1) WPA-Personal (PSK) as home network and WPA-Enterprise with EAP-TLS as work network # allow frontend (e.g., wpa_cli) to be used by all users in 'wheel' group ctrl_interface=/var/run/wpa_supplicant ctrl_interface_group=wheel # # home network; allow all valid ciphers network={ ssid="home" scan_ssid=1 key_mgmt=WPA-PSK psk="very secret passphrase" } # # work network; use EAP-TLS with WPA; allow only CCMP and TKIP ciphers network={ ssid="work" scan_ssid=1 key_mgmt=WPA-EAP pairwise=CCMP TKIP group=CCMP TKIP eap=TLS identity="user@example.com" ca_cert="/etc/cert/ca.pem" client_cert="/etc/cert/user.pem" private_key="/etc/cert/user.prv" private_key_passwd="password" } 2) WPA-RADIUS/EAP-PEAP/MSCHAPv2 with RADIUS servers that use old peaplabel (e.g., Funk Odyssey and SBR, Meetinghouse Aegis, Interlink RAD-Series) ctrl_interface=/var/run/wpa_supplicant ctrl_interface_group=wheel network={ ssid="example" scan_ssid=1 key_mgmt=WPA-EAP eap=PEAP identity="user@example.com" password="foobar" ca_cert="/etc/cert/ca.pem" phase1="peaplabel=0" phase2="auth=MSCHAPV2" } 3) EAP-TTLS/EAP-MD5-Challenge configuration with anonymous identity for the unencrypted use. Real identity is sent only within an encrypted TLS tunnel. ctrl_interface=/var/run/wpa_supplicant ctrl_interface_group=wheel network={ ssid="example" scan_ssid=1 key_mgmt=WPA-EAP eap=TTLS identity="user@example.com" anonymous_identity="anonymous@example.com" password="foobar" ca_cert="/etc/cert/ca.pem" phase2="auth=MD5" } 4) IEEE 802.1X (i.e., no WPA) with dynamic WEP keys (require both unicast and broadcast); use EAP-TLS for authentication ctrl_interface=/var/run/wpa_supplicant ctrl_interface_group=wheel network={ ssid="1x-test" scan_ssid=1 key_mgmt=IEEE8021X eap=TLS identity="user@example.com" ca_cert="/etc/cert/ca.pem" client_cert="/etc/cert/user.pem" private_key="/etc/cert/user.prv" private_key_passwd="password" eapol_flags=3 } 5) Catch all example that allows more or less all configuration modes. The configuration options are used based on what security policy is used in the selected SSID. This is mostly for testing and is not recommended for normal use. ctrl_interface=/var/run/wpa_supplicant ctrl_interface_group=wheel network={ ssid="example" scan_ssid=1 key_mgmt=WPA-EAP WPA-PSK IEEE8021X NONE pairwise=CCMP TKIP group=CCMP TKIP WEP104 WEP40 psk="very secret passphrase" eap=TTLS PEAP TLS identity="user@example.com" password="foobar" ca_cert="/etc/cert/ca.pem" client_cert="/etc/cert/user.pem" private_key="/etc/cert/user.prv" private_key_passwd="password" phase1="peaplabel=0" ca_cert2="/etc/cert/ca2.pem" client_cert2="/etc/cer/user.pem" private_key2="/etc/cer/user.prv" private_key2_passwd="password" } 6) Authentication for wired Ethernet. This can be used with 'wired' or 'roboswitch' interface (-Dwired or -Droboswitch on command line). ctrl_interface=/var/run/wpa_supplicant ctrl_interface_group=wheel ap_scan=0 network={ key_mgmt=IEEE8021X eap=MD5 identity="user" password="password" eapol_flags=0 } Certificates ------------ Some EAP authentication methods require use of certificates. EAP-TLS uses both server side and client certificates whereas EAP-PEAP and EAP-TTLS only require the server side certificate. When client certificate is used, a matching private key file has to also be included in configuration. If the private key uses a passphrase, this has to be configured in wpa_supplicant.conf ("private_key_passwd"). wpa_supplicant supports X.509 certificates in PEM and DER formats. User certificate and private key can be included in the same file. If the user certificate and private key is received in PKCS#12/PFX format, they need to be converted to suitable PEM/DER format for wpa_supplicant. This can be done, e.g., with following commands: # convert client certificate and private key to PEM format openssl pkcs12 -in example.pfx -out user.pem -clcerts # convert CA certificate (if included in PFX file) to PEM format openssl pkcs12 -in example.pfx -out ca.pem -cacerts -nokeys wpa_cli ------- wpa_cli is a text-based frontend program for interacting with wpa_supplicant. It is used to query current status, change configuration, trigger events, and request interactive user input. wpa_cli can show the current authentication status, selected security mode, dot11 and dot1x MIBs, etc. In addition, it can configure some variables like EAPOL state machine parameters and trigger events like reassociation and IEEE 802.1X logoff/logon. wpa_cli provides a user interface to request authentication information, like username and password, if these are not included in the configuration. This can be used to implement, e.g., one-time-passwords or generic token card authentication where the authentication is based on a challenge-response that uses an external device for generating the response. The control interface of wpa_supplicant can be configured to allow non-root user access (ctrl_interface_group in the configuration file). This makes it possible to run wpa_cli with a normal user account. wpa_cli supports two modes: interactive and command line. Both modes share the same command set and the main difference is in interactive mode providing access to unsolicited messages (event messages, username/password requests). Interactive mode is started when wpa_cli is executed without including the command as a command line parameter. Commands are then entered on the wpa_cli prompt. In command line mode, the same commands are entered as command line arguments for wpa_cli. Interactive authentication parameters request When wpa_supplicant need authentication parameters, like username and password, which are not present in the configuration file, it sends a request message to all attached frontend programs, e.g., wpa_cli in interactive mode. wpa_cli shows these requests with "CTRL-REQ-<type>-<id>:<text>" prefix. <type> is IDENTITY, PASSWORD, or OTP (one-time-password). <id> is a unique identifier for the current network. <text> is description of the request. In case of OTP request, it includes the challenge from the authentication server. The reply to these requests can be given with 'identity', 'password', and 'otp' commands. <id> needs to be copied from the the matching request. 'password' and 'otp' commands can be used regardless of whether the request was for PASSWORD or OTP. The main difference between these two commands is that values given with 'password' are remembered as long as wpa_supplicant is running whereas values given with 'otp' are used only once and then forgotten, i.e., wpa_supplicant will ask frontend for a new value for every use. This can be used to implement one-time-password lists and generic token card -based authentication. Example request for password and a matching reply: CTRL-REQ-PASSWORD-1:Password needed for SSID foobar > password 1 mysecretpassword Example request for generic token card challenge-response: CTRL-REQ-OTP-2:Challenge 1235663 needed for SSID foobar > otp 2 9876 wpa_cli commands status = get current WPA/EAPOL/EAP status mib = get MIB variables (dot1x, dot11) help = show this usage help interface [ifname] = show interfaces/select interface level <debug level> = change debug level license = show full wpa_cli license logoff = IEEE 802.1X EAPOL state machine logoff logon = IEEE 802.1X EAPOL state machine logon set = set variables (shows list of variables when run without arguments) pmksa = show PMKSA cache reassociate = force reassociation reconfigure = force wpa_supplicant to re-read its configuration file preauthenticate <BSSID> = force preauthentication identity <network id> <identity> = configure identity for an SSID password <network id> <password> = configure password for an SSID pin <network id> <pin> = configure pin for an SSID otp <network id> <password> = configure one-time-password for an SSID passphrase <network id> <passphrase> = configure private key passphrase for an SSID bssid <network id> <BSSID> = set preferred BSSID for an SSID list_networks = list configured networks select_network <network id> = select a network (disable others) enable_network <network id> = enable a network disable_network <network id> = disable a network add_network = add a network remove_network <network id> = remove a network set_network <network id> <variable> <value> = set network variables (shows list of variables when run without arguments) get_network <network id> <variable> = get network variables save_config = save the current configuration disconnect = disconnect and wait for reassociate command before connecting scan = request new BSS scan scan_results = get latest scan results get_capability <eap/pairwise/group/key_mgmt/proto/auth_alg> = get capabilies terminate = terminate wpa_supplicant quit = exit wpa_cli wpa_cli command line options wpa_cli [-p<path to ctrl sockets>] [-i<ifname>] [-hvB] [-a<action file>] \ [-P<pid file>] [-g<global ctrl>] [command..] -h = help (show this usage text) -v = shown version information -a = run in daemon mode executing the action file based on events from wpa_supplicant -B = run a daemon in the background default path: /var/run/wpa_supplicant default interface: first interface found in socket path Using wpa_cli to run external program on connect/disconnect ----------------------------------------------------------- wpa_cli can used to run external programs whenever wpa_supplicant connects or disconnects from a network. This can be used, e.g., to update network configuration and/or trigget DHCP client to update IP addresses, etc. One wpa_cli process in "action" mode needs to be started for each interface. For example, the following command starts wpa_cli for the default interface (-i can be used to select the interface in case of more than one interface being used at the same time): wpa_cli -a/sbin/wpa_action.sh -B The action file (-a option, /sbin/wpa_action.sh in this example) will be executed whenever wpa_supplicant completes authentication (connect event) or detects disconnection). The action script will be called with two command line arguments: interface name and event (CONNECTED or DISCONNECTED). If the action script needs to get more information about the current network, it can use 'wpa_cli status' to query wpa_supplicant for more information. Following example can be used as a simple template for an action script: #!/bin/sh IFNAME=$1 CMD=$2 if [ "$CMD" = "CONNECTED" ]; then SSID=`wpa_cli -i$IFNAME status | grep ^ssid= | cut -f2- -d=` # configure network, signal DHCP client, etc. fi if [ "$CMD" = "DISCONNECTED" ]; then # remove network configuration, if needed SSID= fi Integrating with pcmcia-cs/cardmgr scripts ------------------------------------------ wpa_supplicant needs to be running when using a wireless network with WPA. It can be started either from system startup scripts or from pcmcia-cs/cardmgr scripts (when using PC Cards). WPA handshake must be completed before data frames can be exchanged, so wpa_supplicant should be started before DHCP client. For example, following small changes to pcmcia-cs scripts can be used to enable WPA support: Add MODE="Managed" and WPA="y" to the network scheme in /etc/pcmcia/wireless.opts. Add the following block to the end of 'start' action handler in /etc/pcmcia/wireless: if [ "$WPA" = "y" -a -x /usr/local/bin/wpa_supplicant ]; then /usr/local/bin/wpa_supplicant -B -c/etc/wpa_supplicant.conf \ -i$DEVICE fi Add the following block to the end of 'stop' action handler (may need to be separated from other actions) in /etc/pcmcia/wireless: if [ "$WPA" = "y" -a -x /usr/local/bin/wpa_supplicant ]; then killall wpa_supplicant fi This will make cardmgr start wpa_supplicant when the card is plugged in. Dynamic interface add and operation without configuration files --------------------------------------------------------------- wpa_supplicant can be started without any configuration files or network interfaces. When used in this way, a global (i.e., per wpa_supplicant process) control interface is used to add and remove network interfaces. Each network interface can then be configured through a per-network interface control interface. For example, following commands show how to start wpa_supplicant without any network interfaces and then add a network interface and configure a network (SSID): # Start wpa_supplicant in the background wpa_supplicant -g/var/run/wpa_supplicant-global -B # Add a new interface (wlan0, no configuration file, driver=nl80211, and # enable control interface) wpa_cli -g/var/run/wpa_supplicant-global interface_add wlan0 \ "" nl80211 /var/run/wpa_supplicant # Configure a network using the newly added network interface: wpa_cli -iwlan0 add_network wpa_cli -iwlan0 set_network 0 ssid '"test"' wpa_cli -iwlan0 set_network 0 key_mgmt WPA-PSK wpa_cli -iwlan0 set_network 0 psk '"12345678"' wpa_cli -iwlan0 set_network 0 pairwise TKIP wpa_cli -iwlan0 set_network 0 group TKIP wpa_cli -iwlan0 set_network 0 proto WPA wpa_cli -iwlan0 enable_network 0 # At this point, the new network interface should start trying to associate # with the WPA-PSK network using SSID test. # Remove network interface wpa_cli -g/var/run/wpa_supplicant-global interface_remove wlan0 Privilege separation -------------------- To minimize the size of code that needs to be run with root privileges (e.g., to control wireless interface operation), wpa_supplicant supports optional privilege separation. If enabled, this separates the privileged operations into a separate process (wpa_priv) while leaving rest of the code (e.g., EAP authentication and WPA handshakes) into an unprivileged process (wpa_supplicant) that can be run as non-root user. Privilege separation restricts the effects of potential software errors by containing the majority of the code in an unprivileged process to avoid full system compromise. Privilege separation is not enabled by default and it can be enabled by adding CONFIG_PRIVSEP=y to the build configuration (.config). When enabled, the privileged operations (driver wrapper and l2_packet) are linked into a separate daemon program, wpa_priv. The unprivileged program, wpa_supplicant, will be built with a special driver/l2_packet wrappers that communicate with the privileged wpa_priv process to perform the needed operations. wpa_priv can control what privileged are allowed. wpa_priv needs to be run with network admin privileges (usually, root user). It opens a UNIX domain socket for each interface that is included on the command line; any other interface will be off limits for wpa_supplicant in this kind of configuration. After this, wpa_supplicant can be run as a non-root user (e.g., all standard users on a laptop or as a special non-privileged user account created just for this purpose to limit access to user files even further). Example configuration: - create user group for users that are allowed to use wpa_supplicant ('wpapriv' in this example) and assign users that should be able to use wpa_supplicant into that group - create /var/run/wpa_priv directory for UNIX domain sockets and control user access by setting it accessible only for the wpapriv group: mkdir /var/run/wpa_priv chown root:wpapriv /var/run/wpa_priv chmod 0750 /var/run/wpa_priv - start wpa_priv as root (e.g., from system startup scripts) with the enabled interfaces configured on the command line: wpa_priv -B -P /var/run/wpa_priv.pid nl80211:wlan0 - run wpa_supplicant as non-root with a user that is in wpapriv group: wpa_supplicant -i ath0 -c wpa_supplicant.conf wpa_priv does not use the network interface before wpa_supplicant is started, so it is fine to include network interfaces that are not available at the time wpa_priv is started. As an alternative, wpa_priv can be started when an interface is added (hotplug/udev/etc. scripts). wpa_priv can control multiple interface with one process, but it is also possible to run multiple wpa_priv processes at the same time, if desired. It should be noted that the interface used between wpa_supplicant and wpa_priv does not include all the capabilities of the wpa_supplicant driver interface and at times, this interface lacks update especially for recent addition. Consequently, use of wpa_priv does come with the price of somewhat reduced available functionality. The next section describing how wpa_supplicant can be used with reduced privileges without having to handle the complexity of separate wpa_priv. While that approve does not provide separation for network admin capabilities, it does allow other root privileges to be dropped without the drawbacks of the wpa_priv process. Linux capabilities instead of privileged process ------------------------------------------------ wpa_supplicant performs operations that need special permissions, e.g., to control the network connection. Traditionally this has been achieved by running wpa_supplicant as a privileged process with effective user id 0 (root). Linux capabilities can be used to provide restricted set of capabilities to match the functions needed by wpa_supplicant. The minimum set of capabilities needed for the operations is CAP_NET_ADMIN and CAP_NET_RAW. setcap(8) can be used to set file capabilities. For example: sudo setcap cap_net_raw,cap_net_admin+ep wpa_supplicant Please note that this would give anyone being able to run that wpa_supplicant binary access to the additional capabilities. This can further be limited by file owner/group and mode bits. For example: sudo chown wpas wpa_supplicant sudo chmod 0100 wpa_supplicant This combination of setcap, chown, and chmod commands would allow wpas user to execute wpa_supplicant with additional network admin/raw capabilities. Common way style of creating a control interface socket in /var/run/wpa_supplicant could not be done by this user, but this directory could be created before starting the wpa_supplicant and set to suitable mode to allow wpa_supplicant to create sockets there. Alternatively, other directory or abstract socket namespace could be used for the control interface. External requests for radio control ----------------------------------- External programs can request wpa_supplicant to not start offchannel operations during other tasks that may need exclusive control of the radio. The RADIO_WORK control interface command can be used for this. "RADIO_WORK add <name> [freq=<MHz>] [timeout=<seconds>]" command can be used to reserve a slot for radio access. If freq is specified, other radio work items on the same channel may be completed in parallel. Otherwise, all other radio work items are blocked during execution. Timeout is set to 10 seconds by default to avoid blocking wpa_supplicant operations for excessive time. If a longer (or shorter) safety timeout is needed, that can be specified with the optional timeout parameter. This command returns an identifier for the radio work item. Once the radio work item has been started, "EXT-RADIO-WORK-START <id>" event message is indicated that the external processing can start. Once the operation has been completed, "RADIO_WORK done <id>" is used to indicate that to wpa_supplicant. This allows other radio works to be performed. If this command is forgotten (e.g., due to the external program terminating), wpa_supplicant will time out the radio work item and send "EXT-RADIO-WORK-TIMEOUT <id>" event to indicate that this has happened. "RADIO_WORK done <id>" can also be used to cancel items that have not yet been started. For example, in wpa_cli interactive mode: > radio_work add test 1 <3>EXT-RADIO-WORK-START 1 > radio_work show ext:test@wlan0:0:1:2.487797 > radio_work done 1 OK > radio_work show > radio_work done 3 OK > radio_work show ext:test freq=2412 timeout=30@wlan0:2412:1:28.583483 <3>EXT-RADIO-WORK-TIMEOUT 2 > radio_work add test2 freq=2412 timeout=60 5 <3>EXT-RADIO-WORK-START 5 > radio_work add test3 6 > radio_work add test4 7 > radio_work show ext:test2 freq=2412 timeout=60@wlan0:2412:1:9.751844 ext:test3@wlan0:0:0:5.071812 ext:test4@wlan0:0:0:3.143870 > radio_work done 6 OK > radio_work show ext:test2 freq=2412 timeout=60@wlan0:2412:1:16.287869 ext:test4@wlan0:0:0:9.679895 > radio_work done 5 OK <3>EXT-RADIO-WORK-START 7 <3>EXT-RADIO-WORK-TIMEOUT 7 |
Name Last modified Size
Parent Directory -
CVS/ 14-Aug-2024 05:04 -
binder/ 14-Feb-2024 19:47 -
dbus/ 02-Mar-2024 04:23 -
doc/ 14-Feb-2024 19:47 -
examples/ 02-Mar-2024 04:23 -
systemd/ 02-Mar-2024 04:23 -
utils/ 02-Mar-2024 04:23 -
vs2005/ 14-Feb-2024 19:47 -
wpa_gui-qt4/ 02-Mar-2024 04:23 -
Android.mk 02-Mar-2024 04:23 37K
ChangeLog 02-Mar-2024 04:23 127K
Makefile 02-Mar-2024 04:23 43K
README 02-Mar-2024 04:23 39K
README-DPP 29-Feb-2024 12:41 5.2K
README-HS20 04-Jan-2019 20:29 22K
README-P2P 02-Mar-2024 04:23 33K
README-WPS 16-Oct-2014 21:16 16K
README-Windows.txt 03-Jan-2014 03:05 12K
android.config 02-Mar-2024 04:23 19K
ap.c 02-Mar-2024 04:23 44K
ap.h 02-Mar-2024 04:23 4.4K
autoscan.c 04-Jan-2019 20:29 3.5K
autoscan.h 21-Nov-2016 17:42 1.4K
autoscan_exponential.c 03-Jan-2014 03:05 2.0K
autoscan_periodic.c 03-Jan-2014 03:05 1.6K
bgscan.c 04-Jan-2019 20:29 2.4K
bgscan.h 21-Nov-2016 17:42 2.1K
bgscan_learn.c 04-Jan-2019 20:29 14K
bgscan_simple.c 04-Jan-2019 20:29 8.0K
blacklist.c 03-Jan-2014 03:05 3.4K
blacklist.h 03-Jan-2014 03:05 660
bss.c 02-Mar-2024 04:23 36K
bss.h 02-Mar-2024 04:23 5.8K
config.c 02-Mar-2024 04:23 119K
config.h 02-Mar-2024 04:23 50K
config_file.c 02-Mar-2024 04:23 42K
config_none.c 16-Oct-2014 21:16 1.3K
config_ssid.h 02-Mar-2024 04:23 27K
config_winreg.c 02-Mar-2024 04:23 25K
ctrl_iface.c 02-Mar-2024 04:23 275K
ctrl_iface.h 16-Oct-2014 21:16 5.3K
ctrl_iface_named_pipe.c 04-Jan-2019 20:29 20K
ctrl_iface_udp.c 04-Jan-2019 20:29 20K
ctrl_iface_unix.c 02-Mar-2024 04:23 35K
defconfig 02-Mar-2024 04:23 22K
dpp_supplicant.c 02-Mar-2024 04:23 64K
dpp_supplicant.h 02-Mar-2024 04:23 1.3K
driver_i.h 02-Mar-2024 04:23 29K
eap_proxy_dummy.mak 16-Oct-2014 21:16 0
eap_proxy_dummy.mk 16-Oct-2014 21:16 0
eap_register.c 02-Mar-2024 04:23 5.2K
eap_testing.txt 04-Aug-2010 12:22 14K
eapol_test.c 02-Mar-2024 04:23 40K
eapol_test.py 02-Mar-2024 04:23 4.4K
events.c 02-Mar-2024 04:23 135K
gas_query.c 02-Mar-2024 04:23 24K
gas_query.h 02-Mar-2024 04:23 1.5K
hs20_supplicant.c 02-Mar-2024 04:23 33K
hs20_supplicant.h 02-Mar-2024 04:23 2.2K
ibss_rsn.c 02-Mar-2024 04:23 23K
ibss_rsn.h 21-Nov-2016 17:42 1.7K
interworking.c 02-Mar-2024 04:23 82K
interworking.h 04-Jan-2019 20:29 1.3K
libwpa_test.c 21-Nov-2016 17:42 611
main.c 02-Mar-2024 04:23 10K
main_none.c 01-Apr-2015 21:24 844
main_winmain.c 01-Apr-2015 21:24 1.7K
main_winsvc.c 01-Apr-2015 21:24 11K
mbo.c 02-Mar-2024 04:23 15K
mesh.c 02-Mar-2024 04:23 19K
mesh.h 21-Nov-2016 17:42 1.4K
mesh_mpm.c 02-Mar-2024 04:23 36K
mesh_mpm.h 21-Nov-2016 17:42 1.5K
mesh_rsn.c 02-Mar-2024 04:23 21K
mesh_rsn.h 21-Nov-2016 17:42 1.4K
nfc_pw_token.c 03-Jan-2014 03:05 1.7K
nmake.mak 04-Aug-2010 12:22 6.6K
notify.c 02-Mar-2024 04:23 21K
notify.h 02-Mar-2024 04:23 7.2K
offchannel.c 04-Jan-2019 20:29 16K
offchannel.h 03-Jan-2014 03:05 1.4K
op_classes.c 02-Mar-2024 04:23 9.4K
p2p_supplicant.c 02-Mar-2024 04:23 270K
p2p_supplicant.h 02-Mar-2024 04:23 13K
p2p_supplicant_sd.c 21-Nov-2016 17:42 31K
preauth_test.c 02-Mar-2024 04:23 8.6K
rrm.c 02-Mar-2024 04:23 41K
scan.c 02-Mar-2024 04:23 80K
scan.h 21-Nov-2016 17:42 2.8K
sme.c 02-Mar-2024 04:23 74K
sme.h 02-Mar-2024 04:23 3.7K
todo.txt 01-Apr-2015 21:24 4.4K
wifi_display.c 04-Jan-2019 20:29 10K
wifi_display.h 16-Oct-2014 21:16 904
win_example.reg 04-Aug-2010 12:23 1.2K
win_if_list.c 03-Jan-2014 03:05 3.7K
wmm_ac.c 02-Mar-2024 04:23 24K
wmm_ac.h 21-Nov-2016 17:42 4.8K
wnm_sta.c 02-Mar-2024 04:23 51K
wnm_sta.h 04-Jan-2019 20:29 2.5K
wpa_cli.c 02-Mar-2024 04:23 122K
wpa_passphrase.c 04-Jan-2019 20:29 1.5K
wpa_priv.c 04-Jan-2019 22:22 30K
wpa_supplicant.c 02-Mar-2024 04:23 206K
wpa_supplicant.conf 02-Mar-2024 04:23 76K
wpa_supplicant_conf.mk 03-Jan-2014 03:05 1.3K
wpa_supplicant_conf.sh 03-Jan-2014 03:05 458
wpa_supplicant_i.h 02-Mar-2024 04:23 46K
wpa_supplicant_template.conf 04-Jan-2019 20:29 136
wpas_glue.c 02-Mar-2024 04:23 34K
wpas_glue.h 21-Nov-2016 17:42 888
wpas_kay.c 02-Mar-2024 04:23 9.9K
wpas_kay.h 04-Jan-2019 20:29 1.1K
wpas_module_tests.c 21-Nov-2016 17:42 2.5K
wps_supplicant.c 02-Mar-2024 04:23 79K
wps_supplicant.h 02-Mar-2024 04:23 5.1K
NLUUG - Open Systems. Open Standards
Become a member
and get discounts on conferences and more, see the NLUUG website!