hostapd EAP-TLS CRL not working

Thu Sep 15 19:57:44 PDT 2011

[Please CC me if possible; I am not subscribed to this list.]

I'm having trouble blacklisting client certificates in my otherwise-
working hostapd WPA2 EAP-TLS setup, using hostapd's internal RADIUS
implementation.  Specifically, hostapd seems to be ignoring the CRL.

I'm really hoping someone can tell me what I'm doing wrong here, because
if I can't blacklist compromised client certificates, I'm gonna have to
pick PSK or some other EAP.

I have already asked the OpenWRT community for help, but I seem to be
the only OpenWRT user using EAP-TLS at all, let alone with a CRL.  I
also checked this list's archive, but could only see a couple of
CRL-related emails.

The AP runs OpenWRT 10.03.1-rc4 (ARM), running hostapd "20100705-1":

    root at widow:~# opkg update
    Downloading http://downloads.openwrt.org/backfire/10.03.1-rc4/ar71xx/packages/Packages.gz.
    Inflating http://downloads.openwrt.org/backfire/10.03.1-rc4/ar71xx/packages/Packages.gz.
    Updated list of available packages in /var/opkg-lists/packages.
    root at widow:~# opkg list hostapd
    hostapd - 20100705-1 - This package contains a full featured IEEE 802.1x/WPA/EAP/RADIUS
     Authenticator.
    root at widow:~# hostapd -v
    hostapd v0.8.x
    User space daemon for IEEE 802.11 AP management,
    IEEE 802.1X/WPA/WPA2/EAP/RADIUS Authenticator
    Copyright (c) 2002-2010, Jouni Malinen <j at w1.fi> and contributors

You can find its source here.  I don't know if this includes the
OpenWRT-specific patches (if any):

    http://downloads.openwrt.org/sources/hostapd-20100705.tar.bz2

The client is Debian Unstable (x86-64), running wpa_supplicant 0.7.3-3:

    root at dali:~# wpa_supplicant -v
    wpa_supplicant v0.7.3
    Copyright (c) 2003-2010, Jouni Malinen <j at w1.fi> and contributors

Here is the hostapd config file:

    ctrl_interface=/var/run/hostapd-phy0
    driver=nl80211
    wmm_ac_bk_cwmin=4
    wmm_ac_bk_cwmax=10
    wmm_ac_bk_aifs=7
    wmm_ac_bk_txop_limit=0
    wmm_ac_bk_acm=0
    wmm_ac_be_aifs=3
    wmm_ac_be_cwmin=4
    wmm_ac_be_cwmax=10
    wmm_ac_be_txop_limit=0
    wmm_ac_be_acm=0
    wmm_ac_vi_aifs=2
    wmm_ac_vi_cwmin=3
    wmm_ac_vi_cwmax=4
    wmm_ac_vi_txop_limit=94
    wmm_ac_vi_acm=0
    wmm_ac_vo_aifs=2
    wmm_ac_vo_cwmin=2
    wmm_ac_vo_cwmax=3
    wmm_ac_vo_txop_limit=47
    wmm_ac_vo_acm=0
    tx_queue_data3_aifs=7
    tx_queue_data3_cwmin=15
    tx_queue_data3_cwmax=1023
    tx_queue_data3_burst=0
    tx_queue_data2_aifs=3
    tx_queue_data2_cwmin=15
    tx_queue_data2_cwmax=63
    tx_queue_data2_burst=0
    tx_queue_data1_aifs=1
    tx_queue_data1_cwmin=7
    tx_queue_data1_cwmax=15
    tx_queue_data1_burst=3.0
    tx_queue_data0_aifs=1
    tx_queue_data0_cwmin=3
    tx_queue_data0_cwmax=7
    tx_queue_data0_burst=1.5
    hw_mode=g
    channel=11

    ieee80211n=1
    ht_capab=[HT20][SHORT-GI-40][DSSS_CCK-40]
    interface=wlan0
    eap_server=1
    eap_user_file=/etc/hostapd/users
    server_cert=/etc/hostapd/hostapd.crt
    private_key=/etc/hostapd/hostapd.key
    ieee8021x=1
    wpa_key_mgmt=WPA-EAP
    wpa_group_rekey=300
    wpa_gmk_rekey=640
    auth_algs=1
    wpa=2
    wpa_pairwise=CCMP
    ssid=cyber
    bridge=br-lan
    wmm_enabled=1
    bssid=54:e6:fc:dc:d4:dc
    ignore_broadcast_ssid=0

    ca_cert=/etc/hostapd/cacrl.crt
    check_crl=1

Here is the cacrl.crt file, it revokes client cert 4dcb9cf5:

That serial (4dcb9cf5) corresponds to the one used on the Debian client
(sorry, I won't attach that cert):

    root at dali:~# certtool -i </etc/wpa_supplicant/dali.crt | grep 4dcb9cf5
            Serial Number (hex): 4dcb9cf5

Here is the output of hostapd without -d's, showing the client
successfully connecting despite the CRL:

    root at widow:~# hostapd /var/run/hostapd-phy0.conf
    Configuration file: /var/run/hostapd-phy0.conf
    Using interface wlan0 with hwaddr 54:e6:fc:dc:d4:dc and ssid 'cyber'
    wlan0: STA 1c:4b:d6:81:b6:18 IEEE 802.11: authenticated
    wlan0: STA 1c:4b:d6:81:b6:18 IEEE 802.11: associated (aid 1)
    CTRL-EVENT-EAP-STARTED 1c:4b:d6:81:b6:18
    CTRL-EVENT-EAP-PROPOSED-METHOD vendor=0 method=1
    CTRL-EVENT-EAP-PROPOSED-METHOD vendor=0 method=13
    CTRL-EVENT-EAP-SUCCESS 1c:4b:d6:81:b6:18
    wlan0: STA 1c:4b:d6:81:b6:18 WPA: pairwise key handshake completed (RSN)
    AP-STA-CONNECTED 1c:4b:d6:81:b6:18
    wlan0: STA 1c:4b:d6:81:b6:18 RADIUS: starting accounting session 4E71C3D6-00000000
    wlan0: STA 1c:4b:d6:81:b6:18 IEEE 802.1X: authenticated - EAP type: 0 ((null))

Attached are hostapd transcripts of more successful connections, with
debugging turned on, with check_crl=1 (as above), and with that line
commented out of the .conf file.  As you can see, they look to be
identical -- as if hostapd isn't even parsing the CRL.

<elided so mailman won't hold for moderation for being too big>

Here is what the client sees:

    root at dali:~# wpa_supplicant -Dwext -iwlan0 -c/etc/wpa_supplicant.conf
    ioctl[SIOCSIWENCODEEXT]: Invalid argument
    ioctl[SIOCSIWENCODEEXT]: Invalid argument
    Trying to associate with 54:e6:fc:dc:d4:dc (SSID='cyber' freq=2462 MHz)
    Associated with 54:e6:fc:dc:d4:dc
    CTRL-EVENT-EAP-STARTED EAP authentication started
    CTRL-EVENT-EAP-PROPOSED-METHOD vendor=0 method=13
    OpenSSL: pending error: error:0D07803A:asn1 encoding routines:ASN1_ITEM_EX_D2I:nested asn1 error
    OpenSSL: pending error: error:140C800D:SSL routines:SSL_use_certificate_file:ASN1 lib
    OpenSSL: pending error: error:0D08303A:asn1 encoding routines:ASN1_TEMPLATE_NOEXP_D2I:nested asn1 error
    OpenSSL: pending error: error:0D0680A8:asn1 encoding routines:ASN1_CHECK_TLEN:wrong tag
    OpenSSL: pending error: error:0D07803A:asn1 encoding routines:ASN1_ITEM_EX_D2I:nested asn1 error
    OpenSSL: pending error: error:04093004:rsa routines:OLD_RSA_PRIV_DECODE:RSA lib
    OpenSSL: pending error: error:0D0680A8:asn1 encoding routines:ASN1_CHECK_TLEN:wrong tag
    OpenSSL: pending error: error:0D07803A:asn1 encoding routines:ASN1_ITEM_EX_D2I:nested asn1 error
    OpenSSL: pending error: error:140CB00D:SSL routines:SSL_use_PrivateKey_file:ASN1 lib
    CTRL-EVENT-EAP-METHOD EAP vendor 0 method 13 (TLS) selected
    CTRL-EVENT-EAP-PEER-CERT depth=1 subject='/C=AU/O=Cyber IT Solutions/ST=Victoria/CN=Cyber IT Solutions'
    CTRL-EVENT-EAP-PEER-CERT depth=0 subject='/C=AU/O=Cyber IT Solutions/ST=Victoria/CN=cyber'
    CTRL-EVENT-EAP-SUCCESS EAP authentication completed successfully
    WPA: Key negotiation completed with 54:e6:fc:dc:d4:dc [PTK=CCMP GTK=CCMP]
    CTRL-EVENT-CONNECTED - Connection to 54:e6:fc:dc:d4:dc completed (auth) [id=0 id_str=]
    CTRL-EVENT-DISCONNECTED bssid=54:e6:fc:dc:d4:dc reason=0
    ioctl[SIOCSIWENCODEEXT]: Invalid argument
    ioctl[SIOCSIWENCODEEXT]: Invalid argument
    Trying to associate with 54:e6:fc:dc:d4:dc (SSID='cyber' freq=2462 MHz)
    ^CCTRL-EVENT-TERMINATING - signal 2 received

PS: from past experience with with SSL issues (OpenLDAP), my first guess
is that OpenWRT's hostapd is compiled against GnuTLS (unconfirmed), and
it will Just Work after recompiling against OpenSSL.