1 From 12fac09b437a1dc8a0f253e265934a8aaf4d2f8b Mon Sep 17 00:00:00 2001
2 From: Jouni Malinen <j@w1.fi>
3 Date: Sun, 1 Oct 2017 12:32:57 +0300
4 Subject: [PATCH 5/8] Fix PTK rekeying to generate a new ANonce
5
6 The Authenticator state machine path for PTK rekeying ended up bypassing
7 the AUTHENTICATION2 state where a new ANonce is generated when going
8 directly to the PTKSTART state since there is no need to try to
9 determine the PMK again in such a case. This is far from ideal since the
10 new PTK would depend on a new nonce only from the supplicant.
11
12 Fix this by generating a new ANonce when moving to the PTKSTART state
13 for the purpose of starting new 4-way handshake to rekey PTK.
14
15 Signed-off-by: Jouni Malinen <j@w1.fi>
16 ---
17 src/ap/wpa_auth.c | 24 +++++++++++++++++++++---
18 1 file changed, 21 insertions(+), 3 deletions(-)
19
20 diff --git a/src/ap/wpa_auth.c b/src/ap/wpa_auth.c
21 index 707971d..bf10cc1 100644
22 --- a/src/ap/wpa_auth.c
23 +++ b/src/ap/wpa_auth.c
24 @@ -1901,6 +1901,21 @@ SM_STATE(WPA_PTK, AUTHENTICATION2)
25 }
26
27
28 +static int wpa_auth_sm_ptk_update(struct wpa_state_machine *sm)
29 +{
30 + if (random_get_bytes(sm->ANonce, WPA_NONCE_LEN)) {
31 + wpa_printf(MSG_ERROR,
32 + "WPA: Failed to get random data for ANonce");
33 + sm->Disconnect = TRUE;
34 + return -1;
35 + }
36 + wpa_hexdump(MSG_DEBUG, "WPA: Assign new ANonce", sm->ANonce,
37 + WPA_NONCE_LEN);
38 + sm->TimeoutCtr = 0;
39 + return 0;
40 +}
41 +
42 +
43 SM_STATE(WPA_PTK, INITPMK)
44 {
45 u8 msk[2 * PMK_LEN];
46 @@ -2458,9 +2473,12 @@ SM_STEP(WPA_PTK)
47 SM_ENTER(WPA_PTK, AUTHENTICATION);
48 else if (sm->ReAuthenticationRequest)
49 SM_ENTER(WPA_PTK, AUTHENTICATION2);
50 - else if (sm->PTKRequest)
51 - SM_ENTER(WPA_PTK, PTKSTART);
52 - else switch (sm->wpa_ptk_state) {
53 + else if (sm->PTKRequest) {
54 + if (wpa_auth_sm_ptk_update(sm) < 0)
55 + SM_ENTER(WPA_PTK, DISCONNECTED);
56 + else
57 + SM_ENTER(WPA_PTK, PTKSTART);
58 + } else switch (sm->wpa_ptk_state) {
59 case WPA_PTK_INITIALIZE:
60 break;
61 case WPA_PTK_DISCONNECT:
62 --
63 2.7.4
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