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FILS: Use AEAD cipher to check received EAPOL-Key frames (STA)

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This changes 4-way handshake authenticator processing to decrypt the
EAPOL-Key frames using an AEAD cipher (AES-SIV with FILS AKMs) before
processing the Key Data field. This replaces Key MIC validation for the
cases where AEAD cipher is used.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>
This commit is contained in:
Jouni Malinen 2015-09-03 17:57:09 +03:00 committed by Jouni Malinen
parent b729fd8df9
commit 0ab1dd0106
1 changed files with 80 additions and 2 deletions
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82
src/rsn_supp/wpa.c
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@ -1806,6 +1806,76 @@ static void wpa_eapol_key_dump(struct wpa_sm *sm,
}
#ifdef CONFIG_FILS
static int wpa_supp_aead_decrypt(struct wpa_sm *sm, u8 *buf, size_t buf_len,
size_t *key_data_len)
{
struct wpa_ptk *ptk;
struct ieee802_1x_hdr *hdr;
struct wpa_eapol_key *key;
u8 *pos, *tmp;
const u8 *aad[1];
size_t aad_len[1];
if (*key_data_len < AES_BLOCK_SIZE) {
wpa_printf(MSG_INFO, "No room for AES-SIV data in the frame");
return -1;
}
if (sm->tptk_set)
ptk = &sm->tptk;
else if (sm->ptk_set)
ptk = &sm->ptk;
else
return -1;
hdr = (struct ieee802_1x_hdr *) buf;
key = (struct wpa_eapol_key *) (hdr + 1);
pos = (u8 *) (key + 1);
pos += 2; /* Pointing at the Encrypted Key Data field */
tmp = os_malloc(*key_data_len);
if (!tmp)
return -1;
/* AES-SIV AAD from EAPOL protocol version field (inclusive) to
* to Key Data (exclusive). */
aad[0] = buf;
aad_len[0] = pos - buf;
if (aes_siv_decrypt(ptk->kek, ptk->kek_len, pos, *key_data_len,
1, aad, aad_len, tmp) < 0) {
wpa_printf(MSG_INFO, "Invalid AES-SIV data in the frame");
bin_clear_free(tmp, *key_data_len);
return -1;
}
/* AEAD decryption and validation completed successfully */
(*key_data_len) -= AES_BLOCK_SIZE;
wpa_hexdump_key(MSG_DEBUG, "WPA: Decrypted Key Data",
tmp, *key_data_len);
/* Replace Key Data field with the decrypted version */
os_memcpy(pos, tmp, *key_data_len);
pos -= 2; /* Key Data Length field */
WPA_PUT_BE16(pos, *key_data_len);
bin_clear_free(tmp, *key_data_len);
if (sm->tptk_set) {
sm->tptk_set = 0;
sm->ptk_set = 1;
os_memcpy(&sm->ptk, &sm->tptk, sizeof(sm->ptk));
os_memset(&sm->tptk, 0, sizeof(sm->tptk));
}
os_memcpy(sm->rx_replay_counter, key->replay_counter,
WPA_REPLAY_COUNTER_LEN);
sm->rx_replay_counter_set = 1;
return 0;
}
#endif /* CONFIG_FILS */
/**
* wpa_sm_rx_eapol - Process received WPA EAPOL frames
* @sm: Pointer to WPA state machine data from wpa_sm_init()
@ -2075,8 +2145,15 @@ int wpa_sm_rx_eapol(struct wpa_sm *sm, const u8 *src_addr,
goto out;
#endif /* CONFIG_PEERKEY */
#ifdef CONFIG_FILS
if (!mic_len && (key_info & WPA_KEY_INFO_ENCR_KEY_DATA)) {
if (wpa_supp_aead_decrypt(sm, tmp, data_len, &key_data_len))
goto out;
}
#endif /* CONFIG_FILS */
if ((sm->proto == WPA_PROTO_RSN || sm->proto == WPA_PROTO_OSEN) &&
(key_info & WPA_KEY_INFO_ENCR_KEY_DATA)) {
(key_info & WPA_KEY_INFO_ENCR_KEY_DATA) && mic_len) {
if (wpa_supplicant_decrypt_key_data(sm, key, mic_len,
ver, key_data,
&key_data_len))
@ -2094,7 +2171,8 @@ int wpa_sm_rx_eapol(struct wpa_sm *sm, const u8 *src_addr,
/* PeerKey 4-Way Handshake */
peerkey_rx_eapol_4way(sm, peerkey, key, key_info, ver,
key_data, key_data_len);
} else if (key_info & WPA_KEY_INFO_MIC) {
} else if (key_info & (WPA_KEY_INFO_MIC |
WPA_KEY_INFO_ENCR_KEY_DATA)) {
/* 3/4 4-Way Handshake */
wpa_supplicant_process_3_of_4(sm, key, ver, key_data,
key_data_len);