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WPA: Extend the wpa_pmk_to_ptk() function to also derive KDK

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Extend the wpa_pmk_to_ptk() to also derive Key Derivation
Key (KDK), which can later be used for secure LTF measurements.

Update the wpa_supplicant and hostapd configuration and the
corresponding WPA and WPA Auth state machine, to allow enabling of KDK
derivation. For now, use a testing parameter to control whether KDK is
derived.

Signed-off-by: Ilan Peer <ilan.peer@intel.com>
This commit is contained in:
Ilan Peer 2020-12-16 13:00:17 +02:00 committed by Jouni Malinen
parent 019507e10e
commit 46c232eb76
14 changed files with 84 additions and 7 deletions
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6
hostapd/config_file.c
View file

@ -4577,6 +4577,12 @@ static int hostapd_config_fill(struct hostapd_config *conf,
bss->disable_11ac = !!atoi(pos);
} else if (os_strcmp(buf, "disable_11ax") == 0) {
bss->disable_11ax = !!atoi(pos);
#ifdef CONFIG_PASN
#ifdef CONFIG_TESTING_OPTIONS
} else if (os_strcmp(buf, "force_kdk_derivation") == 0) {
bss->force_kdk_derivation = atoi(pos);
#endif /* CONFIG_TESTING_OPTIONS */
#endif /* CONFIG_PASN */
} else {
wpa_printf(MSG_ERROR,
"Line %d: unknown configuration item '%s'",

10
src/ap/ap_config.h
View file

@ -862,6 +862,16 @@ struct hostapd_bss_config {
*/
u8 mka_psk_set;
#endif /* CONFIG_MACSEC */
#ifdef CONFIG_PASN
#ifdef CONFIG_TESTING_OPTIONS
/*
* Normally, KDK should be derived if and only if both sides support
* secure LTF. Allow forcing KDK derivation for testing purposes.
*/
int force_kdk_derivation;
#endif /* CONFIG_TESTING_OPTIONS */
#endif /* CONFIG_PASN */
};
/**

3
src/ap/wpa_auth.c
View file

@ -2290,7 +2290,8 @@ static int wpa_derive_ptk(struct wpa_state_machine *sm, const u8 *snonce,
akmp |= WPA_KEY_MGMT_PSK_SHA256;
return wpa_pmk_to_ptk(pmk, pmk_len, "Pairwise key expansion",
sm->wpa_auth->addr, sm->addr, sm->ANonce, snonce,
ptk, akmp, sm->pairwise, z, z_len);
ptk, akmp, sm->pairwise, z, z_len,
sm->wpa_auth->conf.kdk ? WPA_KDK_MAX_LEN : 0);
}

6
src/ap/wpa_auth.h
View file

@ -262,6 +262,12 @@ struct wpa_auth_config {
#ifdef CONFIG_DPP2
int dpp_pfs;
#endif /* CONFIG_DPP2 */
/*
* If set Key Derivation Key should be derived as part of PMK to
* PTK derivation.
*/
bool kdk;
};
typedef enum {

5
src/ap/wpa_auth_glue.c
View file

@ -208,6 +208,11 @@ static void hostapd_wpa_auth_conf(struct hostapd_bss_config *conf,
#ifdef CONFIG_DPP2
wconf->dpp_pfs = conf->dpp_pfs;
#endif /* CONFIG_DPP2 */
#ifdef CONFIG_PASN
#ifdef CONFIG_TESTING_OPTIONS
wconf->kdk = conf->force_kdk_derivation;
#endif /* CONFIG_TESTING_OPTIONS */
#endif /* CONFIG_PASN */
}

22
src/common/wpa_common.c
View file

@ -333,6 +333,7 @@ int wpa_eapol_key_mic(const u8 *key, size_t key_len, int akmp, int ver,
* @ptk: Buffer for pairwise transient key
* @akmp: Negotiated AKM
* @cipher: Negotiated pairwise cipher
* @kdk_len: The length in octets that should be derived for KDK
* Returns: 0 on success, -1 on failure
*
* IEEE Std 802.11i-2004 - 8.5.1.2 Pairwise key hierarchy
@ -348,12 +349,13 @@ int wpa_pmk_to_ptk(const u8 *pmk, size_t pmk_len, const char *label,
const u8 *addr1, const u8 *addr2,
const u8 *nonce1, const u8 *nonce2,
struct wpa_ptk *ptk, int akmp, int cipher,
const u8 *z, size_t z_len)
const u8 *z, size_t z_len, size_t kdk_len)
{
#define MAX_Z_LEN 66 /* with NIST P-521 */
u8 data[2 * ETH_ALEN + 2 * WPA_NONCE_LEN + MAX_Z_LEN];
size_t data_len = 2 * ETH_ALEN + 2 * WPA_NONCE_LEN;
u8 tmp[WPA_KCK_MAX_LEN + WPA_KEK_MAX_LEN + WPA_TK_MAX_LEN];
u8 tmp[WPA_KCK_MAX_LEN + WPA_KEK_MAX_LEN + WPA_TK_MAX_LEN +
WPA_KDK_MAX_LEN];
size_t ptk_len;
#ifdef CONFIG_OWE
int owe_ptk_workaround = 0;
@ -395,16 +397,24 @@ int wpa_pmk_to_ptk(const u8 *pmk, size_t pmk_len, const char *label,
data_len += z_len;
}
if (kdk_len > WPA_KDK_MAX_LEN) {
wpa_printf(MSG_ERROR,
"WPA: KDK len=%zu exceeds max supported len",
kdk_len);
return -1;
}
ptk->kck_len = wpa_kck_len(akmp, pmk_len);
ptk->kek_len = wpa_kek_len(akmp, pmk_len);
ptk->tk_len = wpa_cipher_key_len(cipher);
ptk->kdk_len = kdk_len;
if (ptk->tk_len == 0) {
wpa_printf(MSG_ERROR,
"WPA: Unsupported cipher (0x%x) used in PTK derivation",
cipher);
return -1;
}
ptk_len = ptk->kck_len + ptk->kek_len + ptk->tk_len;
ptk_len = ptk->kck_len + ptk->kek_len + ptk->tk_len + ptk->kdk_len;
if (wpa_key_mgmt_sha384(akmp)) {
#if defined(CONFIG_SUITEB192) || defined(CONFIG_FILS)
@ -488,6 +498,12 @@ int wpa_pmk_to_ptk(const u8 *pmk, size_t pmk_len, const char *label,
os_memcpy(ptk->tk, tmp + ptk->kck_len + ptk->kek_len, ptk->tk_len);
wpa_hexdump_key(MSG_DEBUG, "WPA: TK", ptk->tk, ptk->tk_len);
if (kdk_len) {
os_memcpy(ptk->kdk, tmp + ptk->kck_len + ptk->kek_len +
ptk->tk_len, ptk->kdk_len);
wpa_hexdump_key(MSG_DEBUG, "WPA: KDK", ptk->kdk, ptk->kdk_len);
}
ptk->kek2_len = 0;
ptk->kck2_len = 0;

5
src/common/wpa_common.h
View file

@ -216,6 +216,7 @@ struct wpa_eapol_key {
#define WPA_KCK_MAX_LEN 32
#define WPA_KEK_MAX_LEN 64
#define WPA_TK_MAX_LEN 32
#define WPA_KDK_MAX_LEN 32
#define FILS_ICK_MAX_LEN 48
#define FILS_FT_MAX_LEN 48
@ -229,11 +230,13 @@ struct wpa_ptk {
u8 tk[WPA_TK_MAX_LEN]; /* Temporal Key (TK) */
u8 kck2[WPA_KCK_MAX_LEN]; /* FT reasoc Key Confirmation Key (KCK2) */
u8 kek2[WPA_KEK_MAX_LEN]; /* FT reassoc Key Encryption Key (KEK2) */
u8 kdk[WPA_KDK_MAX_LEN]; /* Key Derivation Key */
size_t kck_len;
size_t kek_len;
size_t tk_len;
size_t kck2_len;
size_t kek2_len;
size_t kdk_len;
int installed; /* 1 if key has already been installed to driver */
};
@ -383,7 +386,7 @@ int wpa_pmk_to_ptk(const u8 *pmk, size_t pmk_len, const char *label,
const u8 *addr1, const u8 *addr2,
const u8 *nonce1, const u8 *nonce2,
struct wpa_ptk *ptk, int akmp, int cipher,
const u8 *z, size_t z_len);
const u8 *z, size_t z_len, size_t kdk_len);
int fils_rmsk_to_pmk(int akmp, const u8 *rmsk, size_t rmsk_len,
const u8 *snonce, const u8 *anonce, const u8 *dh_ss,
size_t dh_ss_len, u8 *pmk, size_t *pmk_len);

5
src/rsn_supp/wpa.c
View file

@ -606,7 +606,8 @@ static int wpa_derive_ptk(struct wpa_sm *sm, const unsigned char *src_addr,
return wpa_pmk_to_ptk(sm->pmk, sm->pmk_len, "Pairwise key expansion",
sm->own_addr, sm->bssid, sm->snonce,
key->key_nonce, ptk, akmp,
sm->pairwise_cipher, z, z_len);
sm->pairwise_cipher, z, z_len,
sm->kdk ? WPA_KDK_MAX_LEN : 0);
}
@ -3184,6 +3185,7 @@ void wpa_sm_set_config(struct wpa_sm *sm, struct rsn_supp_config *config)
sm->p2p = config->p2p;
sm->wpa_rsc_relaxation = config->wpa_rsc_relaxation;
sm->owe_ptk_workaround = config->owe_ptk_workaround;
sm->kdk = config->kdk;
#ifdef CONFIG_FILS
if (config->fils_cache_id) {
sm->fils_cache_id_set = 1;
@ -3206,6 +3208,7 @@ void wpa_sm_set_config(struct wpa_sm *sm, struct rsn_supp_config *config)
sm->wpa_rsc_relaxation = 0;
sm->owe_ptk_workaround = 0;
sm->beacon_prot = 0;
sm->kdk = false;
}
}

1
src/rsn_supp/wpa.h
View file

@ -130,6 +130,7 @@ struct rsn_supp_config {
int owe_ptk_workaround;
const u8 *fils_cache_id;
int beacon_prot;
bool kdk;
};
#ifndef CONFIG_NO_WPA

6
src/rsn_supp/wpa_i.h
View file

@ -73,6 +73,12 @@ struct wpa_sm {
* to be used */
int keyidx_active; /* Key ID for the active TK */
/*
* If set Key Derivation Key should be derived as part of PMK to
* PTK derivation.
*/
bool kdk;
u8 own_addr[ETH_ALEN];
const char *ifname;
const char *bridge_ifname;

2
wlantest/rx_eapol.c
View file

@ -128,7 +128,7 @@ static int try_pmk(struct wlantest *wt, struct wlantest_bss *bss,
"Pairwise key expansion",
bss->bssid, sta->addr, sta->anonce,
sta->snonce, &ptk, sta->key_mgmt,
sta->pairwise_cipher, NULL, 0) < 0 ||
sta->pairwise_cipher, NULL, 0, 0) < 0 ||
check_mic(ptk.kck, ptk.kck_len, sta->key_mgmt, ver, data,
len) < 0) {
return -1;

5
wpa_supplicant/config.c
View file

@ -5149,6 +5149,11 @@ static const struct global_parse_data global_fields[] = {
{ INT_RANGE(extended_key_id, 0, 1), 0 },
#endif /* CONFIG_WNM */
{ INT_RANGE(wowlan_disconnect_on_deinit, 0, 1), 0},
#ifdef CONFIG_PASN
#ifdef CONFIG_TESTING_OPTIONS
{ INT_RANGE(force_kdk_derivation, 0, 1), 0 },
#endif /* CONFIG_TESTING_OPTIONS */
#endif /* CONFIG_PASN */
};
#undef FUNC

10
wpa_supplicant/config.h
View file

@ -1608,6 +1608,16 @@ struct wpa_config {
* 1 = Trigger disconnection
*/
int wowlan_disconnect_on_deinit;
#ifdef CONFIG_PASN
#ifdef CONFIG_TESTING_OPTIONS
/*
* Normally, KDK should be derived if and only if both sides support
* secure LTF. Allow forcing KDK derivation for testing purposes.
*/
int force_kdk_derivation;
#endif /* CONFIG_TESTING_OPTIONS */
#endif /* CONFIG_PASN*/
};

5
wpa_supplicant/wpas_glue.c
View file

@ -1451,5 +1451,10 @@ void wpa_supplicant_rsn_supp_set_config(struct wpa_supplicant *wpa_s,
#endif /* CONFIG_FILS */
conf.beacon_prot = ssid->beacon_prot;
}
#ifdef CONFIG_PASN
#ifdef CONFIG_TESTING_OPTIONS
conf.kdk = wpa_s->conf->force_kdk_derivation;
#endif /* CONFIG_TESTING_OPTIONS */
#endif /* CONFIG_PASN*/
wpa_sm_set_config(wpa_s->wpa, ssid ? &conf : NULL);
}