Fix PTK rekeying to generate a new ANonce

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>

diff --git a/src/ap/wpa_auth.c b/src/ap/wpa_auth.c
index 4a2aef869dfc72d05e1b2bfeb9b0af9be6b33c39..72b56226847e91f2c84fa4d7d375953384558582 100644 (file)
--- a/src/ap/wpa_auth.c
+++ b/src/ap/wpa_auth.c
@@ -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: