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SAE: Store the group order in EC context data

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This makes the SAE implementation a bit simpler by not having to build
the bignum for group order during execution.

Signed-hostap: Jouni Malinen <j@w1.fi>
This commit is contained in:
Jouni Malinen 2013-01-01 11:54:54 +02:00
parent 4925b303db
commit ce46ec8df0
3 changed files with 24 additions and 13 deletions
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18
src/common/sae.c
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@ -227,7 +227,7 @@ static int sae_derive_pwe(struct sae_data *sae, const u8 *addr1,
static int sae_derive_commit(struct sae_data *sae, struct crypto_ec_point *pwe)
{
struct crypto_bignum *x, *bn_rand, *bn_mask, *order;
struct crypto_bignum *x, *bn_rand, *bn_mask;
struct crypto_ec_point *elem;
u8 mask[SAE_MAX_PRIME_LEN];
int ret = -1;
@ -241,15 +241,13 @@ static int sae_derive_commit(struct sae_data *sae, struct crypto_ec_point *pwe)
x = crypto_bignum_init();
bn_rand = crypto_bignum_init_set(sae->sae_rand, sae->prime_len);
bn_mask = crypto_bignum_init_set(mask, sizeof(mask));
order = crypto_bignum_init_set(group19_order, sizeof(group19_order));
elem = crypto_ec_point_init(sae->ec);
if (x == NULL || bn_rand == NULL || bn_mask == NULL || order == NULL ||
elem == NULL)
if (x == NULL || bn_rand == NULL || bn_mask == NULL || elem == NULL)
goto fail;
/* commit-scalar = (rand + mask) modulo r */
crypto_bignum_add(bn_rand, bn_mask, x);
crypto_bignum_mod(x, order, x);
crypto_bignum_mod(x, crypto_ec_get_order(sae->ec), x);
crypto_bignum_to_bin(x, sae->own_commit_scalar,
sizeof(sae->own_commit_scalar), sae->prime_len);
wpa_hexdump(MSG_DEBUG, "SAE: commit-scalar",
@ -271,7 +269,6 @@ static int sae_derive_commit(struct sae_data *sae, struct crypto_ec_point *pwe)
ret = 0;
fail:
crypto_ec_point_deinit(elem, 0);
crypto_bignum_deinit(order, 0);
crypto_bignum_deinit(bn_mask, 1);
os_memset(mask, 0, sizeof(mask));
crypto_bignum_deinit(bn_rand, 1);
@ -378,17 +375,15 @@ static int sae_derive_keys(struct sae_data *sae, const u8 *k)
u8 null_key[SAE_KEYSEED_KEY_LEN], val[SAE_MAX_PRIME_LEN];
u8 keyseed[SHA256_MAC_LEN];
u8 keys[SAE_KCK_LEN + SAE_PMK_LEN];
struct crypto_bignum *order, *own_scalar, *peer_scalar, *tmp;
struct crypto_bignum *own_scalar, *peer_scalar, *tmp;
int ret = -1;
order = crypto_bignum_init_set(group19_order, sizeof(group19_order));
own_scalar = crypto_bignum_init_set(sae->own_commit_scalar,
sae->prime_len);
peer_scalar = crypto_bignum_init_set(sae->peer_commit_scalar,
sae->prime_len);
tmp = crypto_bignum_init();
if (order == NULL || own_scalar == NULL || peer_scalar == NULL ||
tmp == NULL)
if (own_scalar == NULL || peer_scalar == NULL || tmp == NULL)
goto fail;
/* keyseed = H(<0>32, k)
@ -402,7 +397,7 @@ static int sae_derive_keys(struct sae_data *sae, const u8 *k)
wpa_hexdump_key(MSG_DEBUG, "SAE: keyseed", keyseed, sizeof(keyseed));
crypto_bignum_add(own_scalar, peer_scalar, tmp);
crypto_bignum_mod(tmp, order, tmp);
crypto_bignum_mod(tmp, crypto_ec_get_order(sae->ec), tmp);
crypto_bignum_to_bin(tmp, val, sizeof(val), sae->prime_len);
wpa_hexdump(MSG_DEBUG, "SAE: PMKID", val, SAE_PMKID_LEN);
sha256_prf(keyseed, sizeof(keyseed), "SAE KCK and PMK",
@ -417,7 +412,6 @@ fail:
crypto_bignum_deinit(tmp, 0);
crypto_bignum_deinit(peer_scalar, 0);
crypto_bignum_deinit(own_scalar, 0);
crypto_bignum_deinit(order, 0);
return ret;
}