IEEE8021X and WEP40

Zhu Yi yi.zhu at intel.com
Mon Aug 3 02:22:10 EDT 2009


Hi Jouni,

I tried wpa_supplicant for 802.1X dynamic WEP with iwmc3200wifi driver.
It worked for WEP104 but not WEP40. After some digging into the code, it
turns out wpa_supplicant set WEP104 explicitly in file wpa_supplicant
line 1112 (git version) function wpa_supplicant_associate:

#ifdef IEEE8021X_EAPOL
        if (wpa_s->key_mgmt == WPA_KEY_MGMT_IEEE8021X_NO_WPA) {
                if ((ssid->eapol_flags &
                     (EAPOL_FLAG_REQUIRE_KEY_UNICAST |
                      EAPOL_FLAG_REQUIRE_KEY_BROADCAST)) == 0 &&
                    !wep_keys_set) {
                        use_crypt = 0;
                } else {
                        /* Assume that dynamic WEP-104 keys will be used and
                         * set cipher suites in order for drivers to expect
                         * encryption. */
                        cipher_pairwise = cipher_group = CIPHER_WEP104;
                }
        }
#endif /* IEEE8021X_EAPOL */


If I comment the "cipher_pairwise = cipher_group = CIPHER_WEP104" line,
WEP40 works great with 802.1X on my Cisco Aironet 1200 AP. Jouni, Any 
reason we need to set WEP104 in this case? They should already be set to
the correct values earlier in the same function.

Thanks,
-yi



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