SAE: Maintain bignum of group order and prime in context data

This simplifies operations by not having to create bignum instances
multiple times during SAE exchange.

Signed-hostap: Jouni Malinen <j@w1.fi>

diff --git a/src/common/sae.c b/src/common/sae.c
index a182cf50f56b63d76e67b85009ce997fc1fcf478..d5e5e4868bbadb1144d597187ff78a004e25f53e 100644 (file)
--- a/src/common/sae.c
+++ b/src/common/sae.c
@@ -25,6 +25,8 @@ int sae_set_group(struct sae_data *sae, int group)
 
        sae->group = group;
        sae->prime_len = crypto_ec_prime_len(sae->ec);
+       sae->prime = crypto_ec_get_prime(sae->ec);
+       sae->order = crypto_ec_get_order(sae->ec);
 
        return 0;
 }
@@ -97,8 +99,8 @@ static struct crypto_bignum * sae_get_rand_and_mask(struct sae_data *sae)
        struct crypto_bignum *bn;
        size_t prime_len_bits = crypto_ec_prime_len_bits(sae->ec);
 
-       if (crypto_bignum_to_bin(crypto_ec_get_order(sae->ec),
-                                order, sizeof(order), sae->prime_len) < 0)
+       if (crypto_bignum_to_bin(sae->order, order, sizeof(order),
+                                sae->prime_len) < 0)
                return NULL;
 
        if (sae_get_rand(order, prime_len_bits, sae->sae_rand) < 0 ||
@@ -135,8 +137,8 @@ static int sae_test_pwd_seed(struct sae_data *sae, const u8 *pwd_seed,
        int y_bit;
        size_t bits;
 
-       if (crypto_bignum_to_bin(crypto_ec_get_prime(sae->ec),
-                                prime, sizeof(prime), sae->prime_len) < 0)
+       if (crypto_bignum_to_bin(sae->prime, prime, sizeof(prime),
+                                sae->prime_len) < 0)
                return -1;
 
        wpa_hexdump_key(MSG_DEBUG, "SAE: pwd-seed", pwd_seed, SHA256_MAC_LEN);
@@ -271,7 +273,7 @@ static int sae_derive_commit(struct sae_data *sae, struct crypto_ec_point *pwe)
 
        /* commit-scalar = (rand + mask) modulo r */
        crypto_bignum_add(bn_rand, mask, x);
-       crypto_bignum_mod(x, crypto_ec_get_order(sae->ec), x);
+       crypto_bignum_mod(x, sae->order, 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",
@@ -326,10 +328,10 @@ static int sae_check_peer_commit(struct sae_data *sae)
 {
        u8 order[SAE_MAX_PRIME_LEN], prime[SAE_MAX_PRIME_LEN];
 
-       if (crypto_bignum_to_bin(crypto_ec_get_order(sae->ec),
-                                order, sizeof(order), sae->prime_len) < 0 ||
-           crypto_bignum_to_bin(crypto_ec_get_prime(sae->ec),
-                                prime, sizeof(prime), sae->prime_len) < 0)
+       if (crypto_bignum_to_bin(sae->order, order, sizeof(order),
+                                sae->prime_len) < 0 ||
+           crypto_bignum_to_bin(sae->prime, prime, sizeof(prime),
+                                sae->prime_len) < 0)
                return -1;
 
        /* 0 < scalar < r */
@@ -428,7 +430,7 @@ 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, crypto_ec_get_order(sae->ec), tmp);
+       crypto_bignum_mod(tmp, sae->order, 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",

diff --git a/src/common/sae.h b/src/common/sae.h
index b2bb605382237d6c6b19d8bd8eb133a5aaa13393..46ca84d44efd94d698cd199447c8fe31b39b8ba6 100644 (file)
--- a/src/common/sae.h
+++ b/src/common/sae.h
@@ -31,6 +31,8 @@ struct sae_data {
        int group;
        struct crypto_ec *ec;
        int prime_len;
+       const struct crypto_bignum *prime;
+       const struct crypto_bignum *order;
 };
 
 int sae_set_group(struct sae_data *sae, int group);