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mka: Extend CAK/CKN-from-EAP-MSK API to pass in MSK length

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This can be used to allow 256-bit key hierarchy to be derived from
EAP-based authentication. For now, the MSK length is hardcoded to 128
bits, so the previous behavior is maintained.

Signed-off-by: Jouni Malinen <j@w1.fi>
This commit is contained in:
Jouni Malinen 2018-12-26 16:37:49 +02:00
parent 871439b5d5
commit 7251f0badc
5 changed files with 26 additions and 27 deletions
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4
src/pae/ieee802_1x_kay.c
View file

@ -66,8 +66,8 @@ static struct mka_alg mka_alg_tbl[] = {
.icv_len = DEFAULT_ICV_LEN, .icv_len = DEFAULT_ICV_LEN,
.cak_trfm = ieee802_1x_cak_128bits_aes_cmac, .cak_trfm = ieee802_1x_cak_aes_cmac,
.ckn_trfm = ieee802_1x_ckn_128bits_aes_cmac, .ckn_trfm = ieee802_1x_ckn_aes_cmac,
.kek_trfm = ieee802_1x_kek_aes_cmac, .kek_trfm = ieee802_1x_kek_aes_cmac,
.ick_trfm = ieee802_1x_ick_aes_cmac, .ick_trfm = ieee802_1x_ick_aes_cmac,
.icv_hash = ieee802_1x_icv_aes_cmac, .icv_hash = ieee802_1x_icv_aes_cmac,

7
src/pae/ieee802_1x_kay_i.h
View file

@ -68,9 +68,10 @@ struct mka_alg {
u8 parameter[4]; u8 parameter[4];
size_t icv_len; size_t icv_len;
int (*cak_trfm)(const u8 *msk, const u8 *mac1, const u8 *mac2, u8 *cak); int (*cak_trfm)(const u8 *msk, size_t msk_bytes, const u8 *mac1,
int (*ckn_trfm)(const u8 *msk, const u8 *mac1, const u8 *mac2, const u8 *mac2, u8 *cak, size_t cak_bytes);
const u8 *sid, size_t sid_len, u8 *ckn); int (*ckn_trfm)(const u8 *msk, size_t msk_bytes, const u8 *mac1,
const u8 *mac2, const u8 *sid, size_t sid_len, u8 *ckn);
int (*kek_trfm)(const u8 *cak, size_t cak_bytes, int (*kek_trfm)(const u8 *cak, size_t cak_bytes,
const u8 *ckn, size_t ckn_len, const u8 *ckn, size_t ckn_len,
u8 *kek, size_t kek_bytes); u8 *kek, size_t kek_bytes);

19
src/pae/ieee802_1x_key.c
View file

@ -82,31 +82,30 @@ static int aes_kdf(const u8 *kdk, size_t kdk_bits,
} }
/********** AES-CMAC-128 **********/
/** /**
* ieee802_1x_cak_128bits_aes_cmac * ieee802_1x_cak_aes_cmac
* *
* IEEE Std 802.1X-2010, 6.2.2 * IEEE Std 802.1X-2010, 6.2.2
* CAK = KDF(Key, Label, mac1 | mac2, CAKlength) * CAK = KDF(Key, Label, mac1 | mac2, CAKlength)
*/ */
int ieee802_1x_cak_128bits_aes_cmac(const u8 *msk, const u8 *mac1, int ieee802_1x_cak_aes_cmac(const u8 *msk, size_t msk_bytes, const u8 *mac1,
const u8 *mac2, u8 *cak) const u8 *mac2, u8 *cak, size_t cak_bytes)
{ {
u8 context[2 * ETH_ALEN]; u8 context[2 * ETH_ALEN];
joint_two_mac(mac1, mac2, context); joint_two_mac(mac1, mac2, context);
return aes_kdf(msk, 128, "IEEE8021 EAP CAK", return aes_kdf(msk, 8 * msk_bytes, "IEEE8021 EAP CAK",
context, sizeof(context) * 8, 128, cak); context, sizeof(context) * 8, 8 * cak_bytes, cak);
} }
/** /**
* ieee802_1x_ckn_128bits_aes_cmac * ieee802_1x_ckn_aes_cmac
* *
* IEEE Std 802.1X-2010, 6.2.2 * IEEE Std 802.1X-2010, 6.2.2
* CKN = KDF(Key, Label, ID | mac1 | mac2, CKNlength) * CKN = KDF(Key, Label, ID | mac1 | mac2, CKNlength)
*/ */
int ieee802_1x_ckn_128bits_aes_cmac(const u8 *msk, const u8 *mac1, int ieee802_1x_ckn_aes_cmac(const u8 *msk, size_t msk_bytes, const u8 *mac1,
const u8 *mac2, const u8 *sid, const u8 *mac2, const u8 *sid,
size_t sid_bytes, u8 *ckn) size_t sid_bytes, u8 *ckn)
{ {
@ -122,8 +121,8 @@ int ieee802_1x_ckn_128bits_aes_cmac(const u8 *msk, const u8 *mac1,
os_memcpy(context, sid, sid_bytes); os_memcpy(context, sid, sid_bytes);
joint_two_mac(mac1, mac2, context + sid_bytes); joint_two_mac(mac1, mac2, context + sid_bytes);
res = aes_kdf(msk, 128, "IEEE8021 EAP CKN", context, ctx_len * 8, res = aes_kdf(msk, 8 * msk_bytes, "IEEE8021 EAP CKN",
128, ckn); context, ctx_len * 8, 128, ckn);
os_free(context); os_free(context);
return res; return res;
} }

6
src/pae/ieee802_1x_key.h
View file

@ -9,9 +9,9 @@
#ifndef IEEE802_1X_KEY_H #ifndef IEEE802_1X_KEY_H
#define IEEE802_1X_KEY_H #define IEEE802_1X_KEY_H
int ieee802_1x_cak_128bits_aes_cmac(const u8 *msk, const u8 *mac1, int ieee802_1x_cak_aes_cmac(const u8 *msk, size_t msk_bytes, const u8 *mac1,
const u8 *mac2, u8 *cak); const u8 *mac2, u8 *cak, size_t cak_bytes);
int ieee802_1x_ckn_128bits_aes_cmac(const u8 *msk, const u8 *mac1, int ieee802_1x_ckn_aes_cmac(const u8 *msk, size_t msk_bytes, const u8 *mac1,
const u8 *mac2, const u8 *sid, const u8 *mac2, const u8 *sid,
size_t sid_bytes, u8 *ckn); size_t sid_bytes, u8 *ckn);
int ieee802_1x_kek_aes_cmac(const u8 *cak, size_t cak_bytes, const u8 *ckn, int ieee802_1x_kek_aes_cmac(const u8 *cak, size_t cak_bytes, const u8 *ckn,

9
wpa_supplicant/wpas_kay.c
View file

@ -357,8 +357,8 @@ void * ieee802_1x_notify_create_actor(struct wpa_supplicant *wpa_s,
/* Derive CAK from MSK */ /* Derive CAK from MSK */
cak->len = DEFAULT_KEY_LEN; cak->len = DEFAULT_KEY_LEN;
if (ieee802_1x_cak_128bits_aes_cmac(msk->key, wpa_s->own_addr, if (ieee802_1x_cak_aes_cmac(msk->key, msk->len, wpa_s->own_addr,
peer_addr, cak->key)) { peer_addr, cak->key, cak->len)) {
wpa_printf(MSG_ERROR, wpa_printf(MSG_ERROR,
"IEEE 802.1X: Deriving CAK failed"); "IEEE 802.1X: Deriving CAK failed");
goto fail; goto fail;
@ -367,9 +367,8 @@ void * ieee802_1x_notify_create_actor(struct wpa_supplicant *wpa_s,
/* Derive CKN from MSK */ /* Derive CKN from MSK */
ckn->len = DEFAULT_CKN_LEN; ckn->len = DEFAULT_CKN_LEN;
if (ieee802_1x_ckn_128bits_aes_cmac(msk->key, wpa_s->own_addr, if (ieee802_1x_ckn_aes_cmac(msk->key, msk->len, wpa_s->own_addr,
peer_addr, sid, sid_len, peer_addr, sid, sid_len, ckn->name)) {
ckn->name)) {
wpa_printf(MSG_ERROR, wpa_printf(MSG_ERROR,
"IEEE 802.1X: Deriving CKN failed"); "IEEE 802.1X: Deriving CKN failed");
goto fail; goto fail;