eapol: implement rekey support for authenticator

The only changes required was to set the secure bit for message 1,
reset the frame retry counter, and change the 2/4 verifier to use
the rekey flag rather than ptk_complete. This is because we must
set ptk_complete false in order to detect retransmissions of the
4/4 frame.

Initiating a rekey can now be done by simply calling eapol_start().
This commit is contained in:
James Prestwood 2023-01-18 13:17:59 -08:00 committed by Denis Kenzior
parent d504b74c61
commit 995c34450e
1 changed files with 12 additions and 3 deletions

View File

@ -1086,8 +1086,6 @@ static void eapol_send_ptk_1_of_4(struct eapol_sm *sm)
handshake_state_new_anonce(sm->handshake);
sm->handshake->ptk_complete = false;
sm->replay_counter++;
memset(ek, 0, EAPOL_FRAME_LEN(sm->mic_len));
@ -1111,6 +1109,13 @@ static void eapol_send_ptk_1_of_4(struct eapol_sm *sm)
eapol_key_data_append(ek, sm->mic_len, HANDSHAKE_KDE_PMKID, pmkid, 16);
if (sm->handshake->ptk_complete) {
sm->rekey = true;
sm->handshake->ptk_complete = false;
}
ek->secure = sm->rekey;
ek->header.packet_len = L_CPU_TO_BE16(EAPOL_FRAME_LEN(sm->mic_len) +
EAPOL_KEY_DATA_LEN(ek, sm->mic_len) - 4);
@ -1554,7 +1559,7 @@ static void eapol_handle_ptk_2_of_4(struct eapol_sm *sm,
l_debug("ifindex=%u", sm->handshake->ifindex);
if (!eapol_verify_ptk_2_of_4(ek, sm->handshake->ptk_complete))
if (!eapol_verify_ptk_2_of_4(ek, sm->rekey))
return;
if (L_BE64_TO_CPU(ek->key_replay_counter) != sm->replay_counter)
@ -2451,6 +2456,8 @@ static void eapol_eap_complete_cb(enum eap_result result, void *user_data)
/* sm->mic_len will have been set in eapol_eap_results_cb */
sm->frame_retry = 0;
/* Kick off 4-Way Handshake */
eapol_ptk_1_of_4_retry(NULL, sm);
}
@ -2842,6 +2849,8 @@ bool eapol_start(struct eapol_sm *sm)
if (L_WARN_ON(!sm->handshake->have_pmk))
return false;
sm->frame_retry = 0;
/* Kick off handshake */
eapol_ptk_1_of_4_retry(NULL, sm);
}