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Fix PTK rekeying to generate a new ANonce

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The Authenticator state machine path for PTK rekeying ended up bypassing
the AUTHENTICATION2 state where a new ANonce is generated when going
directly to the PTKSTART state since there is no need to try to
determine the PMK again in such a case. This is far from ideal since the
new PTK would depend on a new nonce only from the supplicant.

Fix this by generating a new ANonce when moving to the PTKSTART state
for the purpose of starting new 4-way handshake to rekey PTK.

Signed-off-by: Jouni Malinen <j@w1.fi>
This commit is contained in:
Jouni Malinen 2017-10-01 12:32:57 +03:00
parent 53bb18cc8b
commit 0adc9b28b3
1 changed files with 21 additions and 3 deletions
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24
src/ap/wpa_auth.c
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@ -1952,6 +1952,21 @@ SM_STATE(WPA_PTK, AUTHENTICATION2)
}
static int wpa_auth_sm_ptk_update(struct wpa_state_machine *sm)
{
if (random_get_bytes(sm->ANonce, WPA_NONCE_LEN)) {
wpa_printf(MSG_ERROR,
"WPA: Failed to get random data for ANonce");
sm->Disconnect = TRUE;
return -1;
}
wpa_hexdump(MSG_DEBUG, "WPA: Assign new ANonce", sm->ANonce,
WPA_NONCE_LEN);
sm->TimeoutCtr = 0;
return 0;
}
SM_STATE(WPA_PTK, INITPMK)
{
u8 msk[2 * PMK_LEN];
@ -3131,9 +3146,12 @@ SM_STEP(WPA_PTK)
SM_ENTER(WPA_PTK, AUTHENTICATION);
else if (sm->ReAuthenticationRequest)
SM_ENTER(WPA_PTK, AUTHENTICATION2);
else if (sm->PTKRequest)
SM_ENTER(WPA_PTK, PTKSTART);
else switch (sm->wpa_ptk_state) {
else if (sm->PTKRequest) {
if (wpa_auth_sm_ptk_update(sm) < 0)
SM_ENTER(WPA_PTK, DISCONNECTED);
else
SM_ENTER(WPA_PTK, PTKSTART);
} else switch (sm->wpa_ptk_state) {
case WPA_PTK_INITIALIZE:
break;
case WPA_PTK_DISCONNECT: