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EAP-PEAP peer: Cryptobinding in fast-reconnect case with inner EAP

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This was reported to fail with Windows 2012r2 with "Invalid Compound_MAC
in cryptobinding TLV". It turns out that the server decided to go
through inner EAP method (EAP-MSCHAPv2 in the reported case) even when
using PEAP fast-reconnect. This seems to be against the [MS-PEAP]
specification which claims that inner EAP method is not used in such a
case. This resulted in a different CMK being derived by the server (used
the version that used ISK) and wpa_supplicant (used the version where
IPMK|CMK = TK without ISK when using fast-reconnect).

Fix this interop issue by making wpa_supplicant to use the
fast-reconnect version of CMK derivation only when using TLS session
resumption and the server having not initiated inner EAP method before
going through the cryptobinding exchange.

Signed-off-by: Jouni Malinen <j@w1.fi>
This commit is contained in:
Jouni Malinen 2016-01-05 23:50:50 +02:00
parent cba9ebfdc2
commit acc39435ff
1 changed files with 7 additions and 2 deletions
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9
src/eap_peer/eap_peap.c
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@ -253,6 +253,7 @@ static int eap_peap_derive_cmk(struct eap_sm *sm, struct eap_peap_data *data)
{ {
u8 *tk; u8 *tk;
u8 isk[32], imck[60]; u8 isk[32], imck[60];
int resumed;
/* /*
* Tunnel key (TK) is the first 60 octets of the key generated by * Tunnel key (TK) is the first 60 octets of the key generated by
@ -263,8 +264,12 @@ static int eap_peap_derive_cmk(struct eap_sm *sm, struct eap_peap_data *data)
return -1; return -1;
wpa_hexdump_key(MSG_DEBUG, "EAP-PEAP: TK", tk, 60); wpa_hexdump_key(MSG_DEBUG, "EAP-PEAP: TK", tk, 60);
if (data->reauth && resumed = tls_connection_resumed(sm->ssl_ctx, data->ssl.conn);
tls_connection_resumed(sm->ssl_ctx, data->ssl.conn)) { wpa_printf(MSG_DEBUG,
"EAP-PEAP: CMK derivation - reauth=%d resumed=%d phase2_eap_started=%d phase2_success=%d",
data->reauth, resumed, data->phase2_eap_started,
data->phase2_success);
if (data->reauth && !data->phase2_eap_started && resumed) {
/* Fast-connect: IPMK|CMK = TK */ /* Fast-connect: IPMK|CMK = TK */
os_memcpy(data->ipmk, tk, 40); os_memcpy(data->ipmk, tk, 40);
wpa_hexdump_key(MSG_DEBUG, "EAP-PEAP: IPMK from TK", wpa_hexdump_key(MSG_DEBUG, "EAP-PEAP: IPMK from TK",