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Fix WPA reconfiguration to update GTK

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The group key state machine needs to be re-initialized with possible
updated GTK length when restarting WPA (e.g., when WPS was used to
reconfigure the AP).
This commit is contained in:
Jouni Malinen 2009-09-06 13:55:01 +03:00
parent 1ff733383f
commit e6965d4e5d
1 changed files with 35 additions and 15 deletions
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50
hostapd/wpa.c
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@ -1,6 +1,6 @@
/* /*
* hostapd - IEEE 802.11i-2004 / WPA Authenticator * hostapd - IEEE 802.11i-2004 / WPA Authenticator
* Copyright (c) 2004-2008, Jouni Malinen <j@w1.fi> * Copyright (c) 2004-2009, Jouni Malinen <j@w1.fi>
* *
* This program is free software; you can redistribute it and/or modify * This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as * it under the terms of the GNU General Public License version 2 as
@ -43,6 +43,8 @@ static void wpa_sm_call_step(void *eloop_ctx, void *timeout_ctx);
static void wpa_group_sm_step(struct wpa_authenticator *wpa_auth, static void wpa_group_sm_step(struct wpa_authenticator *wpa_auth,
struct wpa_group *group); struct wpa_group *group);
static void wpa_request_new_ptk(struct wpa_state_machine *sm); static void wpa_request_new_ptk(struct wpa_state_machine *sm);
static int wpa_gtk_update(struct wpa_authenticator *wpa_auth,
struct wpa_group *group);
static const u32 dot11RSNAConfigGroupUpdateCount = 4; static const u32 dot11RSNAConfigGroupUpdateCount = 4;
static const u32 dot11RSNAConfigPairwiseUpdateCount = 4; static const u32 dot11RSNAConfigPairwiseUpdateCount = 4;
@ -285,6 +287,25 @@ static void wpa_auth_pmksa_free_cb(struct rsn_pmksa_cache_entry *entry,
} }
static void wpa_group_set_key_len(struct wpa_group *group, int cipher)
{
switch (cipher) {
case WPA_CIPHER_CCMP:
group->GTK_len = 16;
break;
case WPA_CIPHER_TKIP:
group->GTK_len = 32;
break;
case WPA_CIPHER_WEP104:
group->GTK_len = 13;
break;
case WPA_CIPHER_WEP40:
group->GTK_len = 5;
break;
}
}
static struct wpa_group * wpa_group_init(struct wpa_authenticator *wpa_auth, static struct wpa_group * wpa_group_init(struct wpa_authenticator *wpa_auth,
int vlan_id) int vlan_id)
{ {
@ -299,20 +320,7 @@ static struct wpa_group * wpa_group_init(struct wpa_authenticator *wpa_auth,
group->GTKAuthenticator = TRUE; group->GTKAuthenticator = TRUE;
group->vlan_id = vlan_id; group->vlan_id = vlan_id;
switch (wpa_auth->conf.wpa_group) { wpa_group_set_key_len(group, wpa_auth->conf.wpa_group);
case WPA_CIPHER_CCMP:
group->GTK_len = 16;
break;
case WPA_CIPHER_TKIP:
group->GTK_len = 32;
break;
case WPA_CIPHER_WEP104:
group->GTK_len = 13;
break;
case WPA_CIPHER_WEP40:
group->GTK_len = 5;
break;
}
/* Counter = PRF-256(Random number, "Init Counter", /* Counter = PRF-256(Random number, "Init Counter",
* Local MAC Address || Time) * Local MAC Address || Time)
@ -451,6 +459,7 @@ void wpa_deinit(struct wpa_authenticator *wpa_auth)
int wpa_reconfig(struct wpa_authenticator *wpa_auth, int wpa_reconfig(struct wpa_authenticator *wpa_auth,
struct wpa_auth_config *conf) struct wpa_auth_config *conf)
{ {
struct wpa_group *group;
if (wpa_auth == NULL) if (wpa_auth == NULL)
return 0; return 0;
@ -460,6 +469,17 @@ int wpa_reconfig(struct wpa_authenticator *wpa_auth,
return -1; return -1;
} }
/*
* Reinitialize GTK to make sure it is suitable for the new
* configuration.
*/
group = wpa_auth->group;
wpa_group_set_key_len(group, wpa_auth->conf.wpa_group);
group->GInit = TRUE;
wpa_group_sm_step(wpa_auth, group);
group->GInit = FALSE;
wpa_group_sm_step(wpa_auth, group);
return 0; return 0;
} }