X-Git-Url: http://www.project-moonshot.org/gitweb/?a=blobdiff_plain;f=libeap%2Fsrc%2Fcommon%2Fsae.c;fp=libeap%2Fsrc%2Fcommon%2Fsae.c;h=9f70f036ba7635c9fb6776f74528a13cfdac191f;hb=88e34eecb5769da6526361b35df00fdbe823eac5;hp=0000000000000000000000000000000000000000;hpb=2394142e4bf89e0a9e2a0091ac16bd6442e3d4c7;p=mech_eap.git

diff --git a/libeap/src/common/sae.c b/libeap/src/common/sae.c
new file mode 100644
index 0000000..9f70f03
--- /dev/null
+++ b/libeap/src/common/sae.c
@@ -0,0 +1,1294 @@
+/*
+ * Simultaneous authentication of equals
+ * Copyright (c) 2012-2016, Jouni Malinen <j@w1.fi>
+ *
+ * This software may be distributed under the terms of the BSD license.
+ * See README for more details.
+ */
+
+#include "includes.h"
+
+#include "common.h"
+#include "crypto/crypto.h"
+#include "crypto/sha256.h"
+#include "crypto/random.h"
+#include "crypto/dh_groups.h"
+#include "ieee802_11_defs.h"
+#include "sae.h"
+
+
+int sae_set_group(struct sae_data *sae, int group)
+{
+	struct sae_temporary_data *tmp;
+
+	sae_clear_data(sae);
+	tmp = sae->tmp = os_zalloc(sizeof(*tmp));
+	if (tmp == NULL)
+		return -1;
+
+	/* First, check if this is an ECC group */
+	tmp->ec = crypto_ec_init(group);
+	if (tmp->ec) {
+		sae->group = group;
+		tmp->prime_len = crypto_ec_prime_len(tmp->ec);
+		tmp->prime = crypto_ec_get_prime(tmp->ec);
+		tmp->order = crypto_ec_get_order(tmp->ec);
+		return 0;
+	}
+
+	/* Not an ECC group, check FFC */
+	tmp->dh = dh_groups_get(group);
+	if (tmp->dh) {
+		sae->group = group;
+		tmp->prime_len = tmp->dh->prime_len;
+		if (tmp->prime_len > SAE_MAX_PRIME_LEN) {
+			sae_clear_data(sae);
+			return -1;
+		}
+
+		tmp->prime_buf = crypto_bignum_init_set(tmp->dh->prime,
+							tmp->prime_len);
+		if (tmp->prime_buf == NULL) {
+			sae_clear_data(sae);
+			return -1;
+		}
+		tmp->prime = tmp->prime_buf;
+
+		tmp->order_buf = crypto_bignum_init_set(tmp->dh->order,
+							tmp->dh->order_len);
+		if (tmp->order_buf == NULL) {
+			sae_clear_data(sae);
+			return -1;
+		}
+		tmp->order = tmp->order_buf;
+
+		return 0;
+	}
+
+	/* Unsupported group */
+	return -1;
+}
+
+
+void sae_clear_temp_data(struct sae_data *sae)
+{
+	struct sae_temporary_data *tmp;
+	if (sae == NULL || sae->tmp == NULL)
+		return;
+	tmp = sae->tmp;
+	crypto_ec_deinit(tmp->ec);
+	crypto_bignum_deinit(tmp->prime_buf, 0);
+	crypto_bignum_deinit(tmp->order_buf, 0);
+	crypto_bignum_deinit(tmp->sae_rand, 1);
+	crypto_bignum_deinit(tmp->pwe_ffc, 1);
+	crypto_bignum_deinit(tmp->own_commit_scalar, 0);
+	crypto_bignum_deinit(tmp->own_commit_element_ffc, 0);
+	crypto_bignum_deinit(tmp->peer_commit_element_ffc, 0);
+	crypto_ec_point_deinit(tmp->pwe_ecc, 1);
+	crypto_ec_point_deinit(tmp->own_commit_element_ecc, 0);
+	crypto_ec_point_deinit(tmp->peer_commit_element_ecc, 0);
+	wpabuf_free(tmp->anti_clogging_token);
+	bin_clear_free(tmp, sizeof(*tmp));
+	sae->tmp = NULL;
+}
+
+
+void sae_clear_data(struct sae_data *sae)
+{
+	if (sae == NULL)
+		return;
+	sae_clear_temp_data(sae);
+	crypto_bignum_deinit(sae->peer_commit_scalar, 0);
+	os_memset(sae, 0, sizeof(*sae));
+}
+
+
+static void buf_shift_right(u8 *buf, size_t len, size_t bits)
+{
+	size_t i;
+	for (i = len - 1; i > 0; i--)
+		buf[i] = (buf[i - 1] << (8 - bits)) | (buf[i] >> bits);
+	buf[0] >>= bits;
+}
+
+
+static struct crypto_bignum * sae_get_rand(struct sae_data *sae)
+{
+	u8 val[SAE_MAX_PRIME_LEN];
+	int iter = 0;
+	struct crypto_bignum *bn = NULL;
+	int order_len_bits = crypto_bignum_bits(sae->tmp->order);
+	size_t order_len = (order_len_bits + 7) / 8;
+
+	if (order_len > sizeof(val))
+		return NULL;
+
+	for (;;) {
+		if (iter++ > 100 || random_get_bytes(val, order_len) < 0)
+			return NULL;
+		if (order_len_bits % 8)
+			buf_shift_right(val, order_len, 8 - order_len_bits % 8);
+		bn = crypto_bignum_init_set(val, order_len);
+		if (bn == NULL)
+			return NULL;
+		if (crypto_bignum_is_zero(bn) ||
+		    crypto_bignum_is_one(bn) ||
+		    crypto_bignum_cmp(bn, sae->tmp->order) >= 0) {
+			crypto_bignum_deinit(bn, 0);
+			continue;
+		}
+		break;
+	}
+
+	os_memset(val, 0, order_len);
+	return bn;
+}
+
+
+static struct crypto_bignum * sae_get_rand_and_mask(struct sae_data *sae)
+{
+	crypto_bignum_deinit(sae->tmp->sae_rand, 1);
+	sae->tmp->sae_rand = sae_get_rand(sae);
+	if (sae->tmp->sae_rand == NULL)
+		return NULL;
+	return sae_get_rand(sae);
+}
+
+
+static void sae_pwd_seed_key(const u8 *addr1, const u8 *addr2, u8 *key)
+{
+	wpa_printf(MSG_DEBUG, "SAE: PWE derivation - addr1=" MACSTR
+		   " addr2=" MACSTR, MAC2STR(addr1), MAC2STR(addr2));
+	if (os_memcmp(addr1, addr2, ETH_ALEN) > 0) {
+		os_memcpy(key, addr1, ETH_ALEN);
+		os_memcpy(key + ETH_ALEN, addr2, ETH_ALEN);
+	} else {
+		os_memcpy(key, addr2, ETH_ALEN);
+		os_memcpy(key + ETH_ALEN, addr1, ETH_ALEN);
+	}
+}
+
+
+static struct crypto_bignum *
+get_rand_1_to_p_1(const u8 *prime, size_t prime_len, size_t prime_bits,
+		  int *r_odd)
+{
+	for (;;) {
+		struct crypto_bignum *r;
+		u8 tmp[SAE_MAX_ECC_PRIME_LEN];
+
+		if (random_get_bytes(tmp, prime_len) < 0)
+			break;
+		if (prime_bits % 8)
+			buf_shift_right(tmp, prime_len, 8 - prime_bits % 8);
+		if (os_memcmp(tmp, prime, prime_len) >= 0)
+			continue;
+		r = crypto_bignum_init_set(tmp, prime_len);
+		if (!r)
+			break;
+		if (crypto_bignum_is_zero(r)) {
+			crypto_bignum_deinit(r, 0);
+			continue;
+		}
+
+		*r_odd = tmp[prime_len - 1] & 0x01;
+		return r;
+	}
+
+	return NULL;
+}
+
+
+static int is_quadratic_residue_blind(struct sae_data *sae,
+				      const u8 *prime, size_t bits,
+				      const struct crypto_bignum *qr,
+				      const struct crypto_bignum *qnr,
+				      const struct crypto_bignum *y_sqr)
+{
+	struct crypto_bignum *r, *num;
+	int r_odd, check, res = -1;
+
+	/*
+	 * Use the blinding technique to mask y_sqr while determining
+	 * whether it is a quadratic residue modulo p to avoid leaking
+	 * timing information while determining the Legendre symbol.
+	 *
+	 * v = y_sqr
+	 * r = a random number between 1 and p-1, inclusive
+	 * num = (v * r * r) modulo p
+	 */
+	r = get_rand_1_to_p_1(prime, sae->tmp->prime_len, bits, &r_odd);
+	if (!r)
+		return -1;
+
+	num = crypto_bignum_init();
+	if (!num ||
+	    crypto_bignum_mulmod(y_sqr, r, sae->tmp->prime, num) < 0 ||
+	    crypto_bignum_mulmod(num, r, sae->tmp->prime, num) < 0)
+		goto fail;
+
+	if (r_odd) {
+		/*
+		 * num = (num * qr) module p
+		 * LGR(num, p) = 1 ==> quadratic residue
+		 */
+		if (crypto_bignum_mulmod(num, qr, sae->tmp->prime, num) < 0)
+			goto fail;
+		check = 1;
+	} else {
+		/*
+		 * num = (num * qnr) module p
+		 * LGR(num, p) = -1 ==> quadratic residue
+		 */
+		if (crypto_bignum_mulmod(num, qnr, sae->tmp->prime, num) < 0)
+			goto fail;
+		check = -1;
+	}
+
+	res = crypto_bignum_legendre(num, sae->tmp->prime);
+	if (res == -2) {
+		res = -1;
+		goto fail;
+	}
+	res = res == check;
+fail:
+	crypto_bignum_deinit(num, 1);
+	crypto_bignum_deinit(r, 1);
+	return res;
+}
+
+
+static int sae_test_pwd_seed_ecc(struct sae_data *sae, const u8 *pwd_seed,
+				 const u8 *prime,
+				 const struct crypto_bignum *qr,
+				 const struct crypto_bignum *qnr,
+				 struct crypto_bignum **ret_x_cand)
+{
+	u8 pwd_value[SAE_MAX_ECC_PRIME_LEN];
+	struct crypto_bignum *y_sqr, *x_cand;
+	int res;
+	size_t bits;
+
+	*ret_x_cand = NULL;
+
+	wpa_hexdump_key(MSG_DEBUG, "SAE: pwd-seed", pwd_seed, SHA256_MAC_LEN);
+
+	/* pwd-value = KDF-z(pwd-seed, "SAE Hunting and Pecking", p) */
+	bits = crypto_ec_prime_len_bits(sae->tmp->ec);
+	if (sha256_prf_bits(pwd_seed, SHA256_MAC_LEN, "SAE Hunting and Pecking",
+			    prime, sae->tmp->prime_len, pwd_value, bits) < 0)
+		return -1;
+	if (bits % 8)
+		buf_shift_right(pwd_value, sizeof(pwd_value), 8 - bits % 8);
+	wpa_hexdump_key(MSG_DEBUG, "SAE: pwd-value",
+			pwd_value, sae->tmp->prime_len);
+
+	if (os_memcmp(pwd_value, prime, sae->tmp->prime_len) >= 0)
+		return 0;
+
+	x_cand = crypto_bignum_init_set(pwd_value, sae->tmp->prime_len);
+	if (!x_cand)
+		return -1;
+	y_sqr = crypto_ec_point_compute_y_sqr(sae->tmp->ec, x_cand);
+	if (!y_sqr) {
+		crypto_bignum_deinit(x_cand, 1);
+		return -1;
+	}
+
+	res = is_quadratic_residue_blind(sae, prime, bits, qr, qnr, y_sqr);
+	crypto_bignum_deinit(y_sqr, 1);
+	if (res <= 0) {
+		crypto_bignum_deinit(x_cand, 1);
+		return res;
+	}
+
+	*ret_x_cand = x_cand;
+	return 1;
+}
+
+
+static int sae_test_pwd_seed_ffc(struct sae_data *sae, const u8 *pwd_seed,
+				 struct crypto_bignum *pwe)
+{
+	u8 pwd_value[SAE_MAX_PRIME_LEN];
+	size_t bits = sae->tmp->prime_len * 8;
+	u8 exp[1];
+	struct crypto_bignum *a, *b;
+	int res;
+
+	wpa_hexdump_key(MSG_DEBUG, "SAE: pwd-seed", pwd_seed, SHA256_MAC_LEN);
+
+	/* pwd-value = KDF-z(pwd-seed, "SAE Hunting and Pecking", p) */
+	if (sha256_prf_bits(pwd_seed, SHA256_MAC_LEN, "SAE Hunting and Pecking",
+			    sae->tmp->dh->prime, sae->tmp->prime_len, pwd_value,
+			    bits) < 0)
+		return -1;
+	wpa_hexdump_key(MSG_DEBUG, "SAE: pwd-value", pwd_value,
+			sae->tmp->prime_len);
+
+	if (os_memcmp(pwd_value, sae->tmp->dh->prime, sae->tmp->prime_len) >= 0)
+	{
+		wpa_printf(MSG_DEBUG, "SAE: pwd-value >= p");
+		return 0;
+	}
+
+	/* PWE = pwd-value^((p-1)/r) modulo p */
+
+	a = crypto_bignum_init_set(pwd_value, sae->tmp->prime_len);
+
+	if (sae->tmp->dh->safe_prime) {
+		/*
+		 * r = (p-1)/2 for the group used here, so this becomes:
+		 * PWE = pwd-value^2 modulo p
+		 */
+		exp[0] = 2;
+		b = crypto_bignum_init_set(exp, sizeof(exp));
+	} else {
+		/* Calculate exponent: (p-1)/r */
+		exp[0] = 1;
+		b = crypto_bignum_init_set(exp, sizeof(exp));
+		if (b == NULL ||
+		    crypto_bignum_sub(sae->tmp->prime, b, b) < 0 ||
+		    crypto_bignum_div(b, sae->tmp->order, b) < 0) {
+			crypto_bignum_deinit(b, 0);
+			b = NULL;
+		}
+	}
+
+	if (a == NULL || b == NULL)
+		res = -1;
+	else
+		res = crypto_bignum_exptmod(a, b, sae->tmp->prime, pwe);
+
+	crypto_bignum_deinit(a, 0);
+	crypto_bignum_deinit(b, 0);
+
+	if (res < 0) {
+		wpa_printf(MSG_DEBUG, "SAE: Failed to calculate PWE");
+		return -1;
+	}
+
+	/* if (PWE > 1) --> found */
+	if (crypto_bignum_is_zero(pwe) || crypto_bignum_is_one(pwe)) {
+		wpa_printf(MSG_DEBUG, "SAE: PWE <= 1");
+		return 0;
+	}
+
+	wpa_printf(MSG_DEBUG, "SAE: PWE found");
+	return 1;
+}
+
+
+static int get_random_qr_qnr(const u8 *prime, size_t prime_len,
+			     const struct crypto_bignum *prime_bn,
+			     size_t prime_bits, struct crypto_bignum **qr,
+			     struct crypto_bignum **qnr)
+{
+	*qr = NULL;
+	*qnr = NULL;
+
+	while (!(*qr) || !(*qnr)) {
+		u8 tmp[SAE_MAX_ECC_PRIME_LEN];
+		struct crypto_bignum *q;
+		int res;
+
+		if (random_get_bytes(tmp, prime_len) < 0)
+			break;
+		if (prime_bits % 8)
+			buf_shift_right(tmp, prime_len, 8 - prime_bits % 8);
+		if (os_memcmp(tmp, prime, prime_len) >= 0)
+			continue;
+		q = crypto_bignum_init_set(tmp, prime_len);
+		if (!q)
+			break;
+		res = crypto_bignum_legendre(q, prime_bn);
+
+		if (res == 1 && !(*qr))
+			*qr = q;
+		else if (res == -1 && !(*qnr))
+			*qnr = q;
+		else
+			crypto_bignum_deinit(q, 0);
+	}
+
+	return (*qr && *qnr) ? 0 : -1;
+}
+
+
+static int sae_derive_pwe_ecc(struct sae_data *sae, const u8 *addr1,
+			      const u8 *addr2, const u8 *password,
+			      size_t password_len)
+{
+	u8 counter, k = 40;
+	u8 addrs[2 * ETH_ALEN];
+	const u8 *addr[2];
+	size_t len[2];
+	u8 dummy_password[32];
+	size_t dummy_password_len;
+	int pwd_seed_odd = 0;
+	u8 prime[SAE_MAX_ECC_PRIME_LEN];
+	size_t prime_len;
+	struct crypto_bignum *x = NULL, *qr, *qnr;
+	size_t bits;
+	int res;
+
+	dummy_password_len = password_len;
+	if (dummy_password_len > sizeof(dummy_password))
+		dummy_password_len = sizeof(dummy_password);
+	if (random_get_bytes(dummy_password, dummy_password_len) < 0)
+		return -1;
+
+	prime_len = sae->tmp->prime_len;
+	if (crypto_bignum_to_bin(sae->tmp->prime, prime, sizeof(prime),
+				 prime_len) < 0)
+		return -1;
+	bits = crypto_ec_prime_len_bits(sae->tmp->ec);
+
+	/*
+	 * Create a random quadratic residue (qr) and quadratic non-residue
+	 * (qnr) modulo p for blinding purposes during the loop.
+	 */
+	if (get_random_qr_qnr(prime, prime_len, sae->tmp->prime, bits,
+			      &qr, &qnr) < 0)
+		return -1;
+
+	wpa_hexdump_ascii_key(MSG_DEBUG, "SAE: password",
+			      password, password_len);
+
+	/*
+	 * H(salt, ikm) = HMAC-SHA256(salt, ikm)
+	 * base = password
+	 * pwd-seed = H(MAX(STA-A-MAC, STA-B-MAC) || MIN(STA-A-MAC, STA-B-MAC),
+	 *              base || counter)
+	 */
+	sae_pwd_seed_key(addr1, addr2, addrs);
+
+	addr[0] = password;
+	len[0] = password_len;
+	addr[1] = &counter;
+	len[1] = sizeof(counter);
+
+	/*
+	 * Continue for at least k iterations to protect against side-channel
+	 * attacks that attempt to determine the number of iterations required
+	 * in the loop.
+	 */
+	for (counter = 1; counter <= k || !x; counter++) {
+		u8 pwd_seed[SHA256_MAC_LEN];
+		struct crypto_bignum *x_cand;
+
+		if (counter > 200) {
+			/* This should not happen in practice */
+			wpa_printf(MSG_DEBUG, "SAE: Failed to derive PWE");
+			break;
+		}
+
+		wpa_printf(MSG_DEBUG, "SAE: counter = %u", counter);
+		if (hmac_sha256_vector(addrs, sizeof(addrs), 2, addr, len,
+				       pwd_seed) < 0)
+			break;
+
+		res = sae_test_pwd_seed_ecc(sae, pwd_seed,
+					    prime, qr, qnr, &x_cand);
+		if (res < 0)
+			goto fail;
+		if (res > 0 && !x) {
+			wpa_printf(MSG_DEBUG,
+				   "SAE: Selected pwd-seed with counter %u",
+				   counter);
+			x = x_cand;
+			pwd_seed_odd = pwd_seed[SHA256_MAC_LEN - 1] & 0x01;
+			os_memset(pwd_seed, 0, sizeof(pwd_seed));
+
+			/*
+			 * Use a dummy password for the following rounds, if
+			 * any.
+			 */
+			addr[0] = dummy_password;
+			len[0] = dummy_password_len;
+		} else if (res > 0) {
+			crypto_bignum_deinit(x_cand, 1);
+		}
+	}
+
+	if (!x) {
+		wpa_printf(MSG_DEBUG, "SAE: Could not generate PWE");
+		res = -1;
+		goto fail;
+	}
+
+	if (!sae->tmp->pwe_ecc)
+		sae->tmp->pwe_ecc = crypto_ec_point_init(sae->tmp->ec);
+	if (!sae->tmp->pwe_ecc)
+		res = -1;
+	else
+		res = crypto_ec_point_solve_y_coord(sae->tmp->ec,
+						    sae->tmp->pwe_ecc, x,
+						    pwd_seed_odd);
+	crypto_bignum_deinit(x, 1);
+	if (res < 0) {
+		/*
+		 * This should not happen since we already checked that there
+		 * is a result.
+		 */
+		wpa_printf(MSG_DEBUG, "SAE: Could not solve y");
+	}
+
+fail:
+	crypto_bignum_deinit(qr, 0);
+	crypto_bignum_deinit(qnr, 0);
+
+	return res;
+}
+
+
+static int sae_derive_pwe_ffc(struct sae_data *sae, const u8 *addr1,
+			      const u8 *addr2, const u8 *password,
+			      size_t password_len)
+{
+	u8 counter;
+	u8 addrs[2 * ETH_ALEN];
+	const u8 *addr[2];
+	size_t len[2];
+	int found = 0;
+
+	if (sae->tmp->pwe_ffc == NULL) {
+		sae->tmp->pwe_ffc = crypto_bignum_init();
+		if (sae->tmp->pwe_ffc == NULL)
+			return -1;
+	}
+
+	wpa_hexdump_ascii_key(MSG_DEBUG, "SAE: password",
+			      password, password_len);
+
+	/*
+	 * H(salt, ikm) = HMAC-SHA256(salt, ikm)
+	 * pwd-seed = H(MAX(STA-A-MAC, STA-B-MAC) || MIN(STA-A-MAC, STA-B-MAC),
+	 *              password || counter)
+	 */
+	sae_pwd_seed_key(addr1, addr2, addrs);
+
+	addr[0] = password;
+	len[0] = password_len;
+	addr[1] = &counter;
+	len[1] = sizeof(counter);
+
+	for (counter = 1; !found; counter++) {
+		u8 pwd_seed[SHA256_MAC_LEN];
+		int res;
+
+		if (counter > 200) {
+			/* This should not happen in practice */
+			wpa_printf(MSG_DEBUG, "SAE: Failed to derive PWE");
+			break;
+		}
+
+		wpa_printf(MSG_DEBUG, "SAE: counter = %u", counter);
+		if (hmac_sha256_vector(addrs, sizeof(addrs), 2, addr, len,
+				       pwd_seed) < 0)
+			break;
+		res = sae_test_pwd_seed_ffc(sae, pwd_seed, sae->tmp->pwe_ffc);
+		if (res < 0)
+			break;
+		if (res > 0) {
+			wpa_printf(MSG_DEBUG, "SAE: Use this PWE");
+			found = 1;
+		}
+	}
+
+	return found ? 0 : -1;
+}
+
+
+static int sae_derive_commit_element_ecc(struct sae_data *sae,
+					 struct crypto_bignum *mask)
+{
+	/* COMMIT-ELEMENT = inverse(scalar-op(mask, PWE)) */
+	if (!sae->tmp->own_commit_element_ecc) {
+		sae->tmp->own_commit_element_ecc =
+			crypto_ec_point_init(sae->tmp->ec);
+		if (!sae->tmp->own_commit_element_ecc)
+			return -1;
+	}
+
+	if (crypto_ec_point_mul(sae->tmp->ec, sae->tmp->pwe_ecc, mask,
+				sae->tmp->own_commit_element_ecc) < 0 ||
+	    crypto_ec_point_invert(sae->tmp->ec,
+				   sae->tmp->own_commit_element_ecc) < 0) {
+		wpa_printf(MSG_DEBUG, "SAE: Could not compute commit-element");
+		return -1;
+	}
+
+	return 0;
+}
+
+
+static int sae_derive_commit_element_ffc(struct sae_data *sae,
+					 struct crypto_bignum *mask)
+{
+	/* COMMIT-ELEMENT = inverse(scalar-op(mask, PWE)) */
+	if (!sae->tmp->own_commit_element_ffc) {
+		sae->tmp->own_commit_element_ffc = crypto_bignum_init();
+		if (!sae->tmp->own_commit_element_ffc)
+			return -1;
+	}
+
+	if (crypto_bignum_exptmod(sae->tmp->pwe_ffc, mask, sae->tmp->prime,
+				  sae->tmp->own_commit_element_ffc) < 0 ||
+	    crypto_bignum_inverse(sae->tmp->own_commit_element_ffc,
+				  sae->tmp->prime,
+				  sae->tmp->own_commit_element_ffc) < 0) {
+		wpa_printf(MSG_DEBUG, "SAE: Could not compute commit-element");
+		return -1;
+	}
+
+	return 0;
+}
+
+
+static int sae_derive_commit(struct sae_data *sae)
+{
+	struct crypto_bignum *mask;
+	int ret = -1;
+	unsigned int counter = 0;
+
+	do {
+		counter++;
+		if (counter > 100) {
+			/*
+			 * This cannot really happen in practice if the random
+			 * number generator is working. Anyway, to avoid even a
+			 * theoretical infinite loop, break out after 100
+			 * attemps.
+			 */
+			return -1;
+		}
+
+		mask = sae_get_rand_and_mask(sae);
+		if (mask == NULL) {
+			wpa_printf(MSG_DEBUG, "SAE: Could not get rand/mask");
+			return -1;
+		}
+
+		/* commit-scalar = (rand + mask) modulo r */
+		if (!sae->tmp->own_commit_scalar) {
+			sae->tmp->own_commit_scalar = crypto_bignum_init();
+			if (!sae->tmp->own_commit_scalar)
+				goto fail;
+		}
+		crypto_bignum_add(sae->tmp->sae_rand, mask,
+				  sae->tmp->own_commit_scalar);
+		crypto_bignum_mod(sae->tmp->own_commit_scalar, sae->tmp->order,
+				  sae->tmp->own_commit_scalar);
+	} while (crypto_bignum_is_zero(sae->tmp->own_commit_scalar) ||
+		 crypto_bignum_is_one(sae->tmp->own_commit_scalar));
+
+	if ((sae->tmp->ec && sae_derive_commit_element_ecc(sae, mask) < 0) ||
+	    (sae->tmp->dh && sae_derive_commit_element_ffc(sae, mask) < 0))
+		goto fail;
+
+	ret = 0;
+fail:
+	crypto_bignum_deinit(mask, 1);
+	return ret;
+}
+
+
+int sae_prepare_commit(const u8 *addr1, const u8 *addr2,
+		       const u8 *password, size_t password_len,
+		       struct sae_data *sae)
+{
+	if (sae->tmp == NULL ||
+	    (sae->tmp->ec && sae_derive_pwe_ecc(sae, addr1, addr2, password,
+						password_len) < 0) ||
+	    (sae->tmp->dh && sae_derive_pwe_ffc(sae, addr1, addr2, password,
+						password_len) < 0) ||
+	    sae_derive_commit(sae) < 0)
+		return -1;
+	return 0;
+}
+
+
+static int sae_derive_k_ecc(struct sae_data *sae, u8 *k)
+{
+	struct crypto_ec_point *K;
+	int ret = -1;
+
+	K = crypto_ec_point_init(sae->tmp->ec);
+	if (K == NULL)
+		goto fail;
+
+	/*
+	 * K = scalar-op(rand, (elem-op(scalar-op(peer-commit-scalar, PWE),
+	 *                                        PEER-COMMIT-ELEMENT)))
+	 * If K is identity element (point-at-infinity), reject
+	 * k = F(K) (= x coordinate)
+	 */
+
+	if (crypto_ec_point_mul(sae->tmp->ec, sae->tmp->pwe_ecc,
+				sae->peer_commit_scalar, K) < 0 ||
+	    crypto_ec_point_add(sae->tmp->ec, K,
+				sae->tmp->peer_commit_element_ecc, K) < 0 ||
+	    crypto_ec_point_mul(sae->tmp->ec, K, sae->tmp->sae_rand, K) < 0 ||
+	    crypto_ec_point_is_at_infinity(sae->tmp->ec, K) ||
+	    crypto_ec_point_to_bin(sae->tmp->ec, K, k, NULL) < 0) {
+		wpa_printf(MSG_DEBUG, "SAE: Failed to calculate K and k");
+		goto fail;
+	}
+
+	wpa_hexdump_key(MSG_DEBUG, "SAE: k", k, sae->tmp->prime_len);
+
+	ret = 0;
+fail:
+	crypto_ec_point_deinit(K, 1);
+	return ret;
+}
+
+
+static int sae_derive_k_ffc(struct sae_data *sae, u8 *k)
+{
+	struct crypto_bignum *K;
+	int ret = -1;
+
+	K = crypto_bignum_init();
+	if (K == NULL)
+		goto fail;
+
+	/*
+	 * K = scalar-op(rand, (elem-op(scalar-op(peer-commit-scalar, PWE),
+	 *                                        PEER-COMMIT-ELEMENT)))
+	 * If K is identity element (one), reject.
+	 * k = F(K) (= x coordinate)
+	 */
+
+	if (crypto_bignum_exptmod(sae->tmp->pwe_ffc, sae->peer_commit_scalar,
+				  sae->tmp->prime, K) < 0 ||
+	    crypto_bignum_mulmod(K, sae->tmp->peer_commit_element_ffc,
+				 sae->tmp->prime, K) < 0 ||
+	    crypto_bignum_exptmod(K, sae->tmp->sae_rand, sae->tmp->prime, K) < 0
+	    ||
+	    crypto_bignum_is_one(K) ||
+	    crypto_bignum_to_bin(K, k, SAE_MAX_PRIME_LEN, sae->tmp->prime_len) <
+	    0) {
+		wpa_printf(MSG_DEBUG, "SAE: Failed to calculate K and k");
+		goto fail;
+	}
+
+	wpa_hexdump_key(MSG_DEBUG, "SAE: k", k, sae->tmp->prime_len);
+
+	ret = 0;
+fail:
+	crypto_bignum_deinit(K, 1);
+	return ret;
+}
+
+
+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 *tmp;
+	int ret = -1;
+
+	tmp = crypto_bignum_init();
+	if (tmp == NULL)
+		goto fail;
+
+	/* keyseed = H(<0>32, k)
+	 * KCK || PMK = KDF-512(keyseed, "SAE KCK and PMK",
+	 *                      (commit-scalar + peer-commit-scalar) modulo r)
+	 * PMKID = L((commit-scalar + peer-commit-scalar) modulo r, 0, 128)
+	 */
+
+	os_memset(null_key, 0, sizeof(null_key));
+	hmac_sha256(null_key, sizeof(null_key), k, sae->tmp->prime_len,
+		    keyseed);
+	wpa_hexdump_key(MSG_DEBUG, "SAE: keyseed", keyseed, sizeof(keyseed));
+
+	crypto_bignum_add(sae->tmp->own_commit_scalar, sae->peer_commit_scalar,
+			  tmp);
+	crypto_bignum_mod(tmp, sae->tmp->order, tmp);
+	crypto_bignum_to_bin(tmp, val, sizeof(val), sae->tmp->prime_len);
+	wpa_hexdump(MSG_DEBUG, "SAE: PMKID", val, SAE_PMKID_LEN);
+	if (sha256_prf(keyseed, sizeof(keyseed), "SAE KCK and PMK",
+		       val, sae->tmp->prime_len, keys, sizeof(keys)) < 0)
+		goto fail;
+	os_memset(keyseed, 0, sizeof(keyseed));
+	os_memcpy(sae->tmp->kck, keys, SAE_KCK_LEN);
+	os_memcpy(sae->pmk, keys + SAE_KCK_LEN, SAE_PMK_LEN);
+	os_memcpy(sae->pmkid, val, SAE_PMKID_LEN);
+	os_memset(keys, 0, sizeof(keys));
+	wpa_hexdump_key(MSG_DEBUG, "SAE: KCK", sae->tmp->kck, SAE_KCK_LEN);
+	wpa_hexdump_key(MSG_DEBUG, "SAE: PMK", sae->pmk, SAE_PMK_LEN);
+
+	ret = 0;
+fail:
+	crypto_bignum_deinit(tmp, 0);
+	return ret;
+}
+
+
+int sae_process_commit(struct sae_data *sae)
+{
+	u8 k[SAE_MAX_PRIME_LEN];
+	if (sae->tmp == NULL ||
+	    (sae->tmp->ec && sae_derive_k_ecc(sae, k) < 0) ||
+	    (sae->tmp->dh && sae_derive_k_ffc(sae, k) < 0) ||
+	    sae_derive_keys(sae, k) < 0)
+		return -1;
+	return 0;
+}
+
+
+void sae_write_commit(struct sae_data *sae, struct wpabuf *buf,
+		      const struct wpabuf *token)
+{
+	u8 *pos;
+
+	if (sae->tmp == NULL)
+		return;
+
+	wpabuf_put_le16(buf, sae->group); /* Finite Cyclic Group */
+	if (token) {
+		wpabuf_put_buf(buf, token);
+		wpa_hexdump(MSG_DEBUG, "SAE: Anti-clogging token",
+			    wpabuf_head(token), wpabuf_len(token));
+	}
+	pos = wpabuf_put(buf, sae->tmp->prime_len);
+	crypto_bignum_to_bin(sae->tmp->own_commit_scalar, pos,
+			     sae->tmp->prime_len, sae->tmp->prime_len);
+	wpa_hexdump(MSG_DEBUG, "SAE: own commit-scalar",
+		    pos, sae->tmp->prime_len);
+	if (sae->tmp->ec) {
+		pos = wpabuf_put(buf, 2 * sae->tmp->prime_len);
+		crypto_ec_point_to_bin(sae->tmp->ec,
+				       sae->tmp->own_commit_element_ecc,
+				       pos, pos + sae->tmp->prime_len);
+		wpa_hexdump(MSG_DEBUG, "SAE: own commit-element(x)",
+			    pos, sae->tmp->prime_len);
+		wpa_hexdump(MSG_DEBUG, "SAE: own commit-element(y)",
+			    pos + sae->tmp->prime_len, sae->tmp->prime_len);
+	} else {
+		pos = wpabuf_put(buf, sae->tmp->prime_len);
+		crypto_bignum_to_bin(sae->tmp->own_commit_element_ffc, pos,
+				     sae->tmp->prime_len, sae->tmp->prime_len);
+		wpa_hexdump(MSG_DEBUG, "SAE: own commit-element",
+			    pos, sae->tmp->prime_len);
+	}
+}
+
+
+u16 sae_group_allowed(struct sae_data *sae, int *allowed_groups, u16 group)
+{
+	if (allowed_groups) {
+		int i;
+		for (i = 0; allowed_groups[i] > 0; i++) {
+			if (allowed_groups[i] == group)
+				break;
+		}
+		if (allowed_groups[i] != group) {
+			wpa_printf(MSG_DEBUG, "SAE: Proposed group %u not "
+				   "enabled in the current configuration",
+				   group);
+			return WLAN_STATUS_FINITE_CYCLIC_GROUP_NOT_SUPPORTED;
+		}
+	}
+
+	if (sae->state == SAE_COMMITTED && group != sae->group) {
+		wpa_printf(MSG_DEBUG, "SAE: Do not allow group to be changed");
+		return WLAN_STATUS_FINITE_CYCLIC_GROUP_NOT_SUPPORTED;
+	}
+
+	if (group != sae->group && sae_set_group(sae, group) < 0) {
+		wpa_printf(MSG_DEBUG, "SAE: Unsupported Finite Cyclic Group %u",
+			   group);
+		return WLAN_STATUS_FINITE_CYCLIC_GROUP_NOT_SUPPORTED;
+	}
+
+	if (sae->tmp == NULL) {
+		wpa_printf(MSG_DEBUG, "SAE: Group information not yet initialized");
+		return WLAN_STATUS_UNSPECIFIED_FAILURE;
+	}
+
+	if (sae->tmp->dh && !allowed_groups) {
+		wpa_printf(MSG_DEBUG, "SAE: Do not allow FFC group %u without "
+			   "explicit configuration enabling it", group);
+		return WLAN_STATUS_FINITE_CYCLIC_GROUP_NOT_SUPPORTED;
+	}
+
+	return WLAN_STATUS_SUCCESS;
+}
+
+
+static void sae_parse_commit_token(struct sae_data *sae, const u8 **pos,
+				   const u8 *end, const u8 **token,
+				   size_t *token_len)
+{
+	if ((sae->tmp->ec ? 3 : 2) * sae->tmp->prime_len < end - *pos) {
+		size_t tlen = end - (*pos + (sae->tmp->ec ? 3 : 2) *
+				     sae->tmp->prime_len);
+		wpa_hexdump(MSG_DEBUG, "SAE: Anti-Clogging Token", *pos, tlen);
+		if (token)
+			*token = *pos;
+		if (token_len)
+			*token_len = tlen;
+		*pos += tlen;
+	} else {
+		if (token)
+			*token = NULL;
+		if (token_len)
+			*token_len = 0;
+	}
+}
+
+
+static u16 sae_parse_commit_scalar(struct sae_data *sae, const u8 **pos,
+				   const u8 *end)
+{
+	struct crypto_bignum *peer_scalar;
+
+	if (sae->tmp->prime_len > end - *pos) {
+		wpa_printf(MSG_DEBUG, "SAE: Not enough data for scalar");
+		return WLAN_STATUS_UNSPECIFIED_FAILURE;
+	}
+
+	peer_scalar = crypto_bignum_init_set(*pos, sae->tmp->prime_len);
+	if (peer_scalar == NULL)
+		return WLAN_STATUS_UNSPECIFIED_FAILURE;
+
+	/*
+	 * IEEE Std 802.11-2012, 11.3.8.6.1: If there is a protocol instance for
+	 * the peer and it is in Authenticated state, the new Commit Message
+	 * shall be dropped if the peer-scalar is identical to the one used in
+	 * the existing protocol instance.
+	 */
+	if (sae->state == SAE_ACCEPTED && sae->peer_commit_scalar &&
+	    crypto_bignum_cmp(sae->peer_commit_scalar, peer_scalar) == 0) {
+		wpa_printf(MSG_DEBUG, "SAE: Do not accept re-use of previous "
+			   "peer-commit-scalar");
+		crypto_bignum_deinit(peer_scalar, 0);
+		return WLAN_STATUS_UNSPECIFIED_FAILURE;
+	}
+
+	/* 1 < scalar < r */
+	if (crypto_bignum_is_zero(peer_scalar) ||
+	    crypto_bignum_is_one(peer_scalar) ||
+	    crypto_bignum_cmp(peer_scalar, sae->tmp->order) >= 0) {
+		wpa_printf(MSG_DEBUG, "SAE: Invalid peer scalar");
+		crypto_bignum_deinit(peer_scalar, 0);
+		return WLAN_STATUS_UNSPECIFIED_FAILURE;
+	}
+
+
+	crypto_bignum_deinit(sae->peer_commit_scalar, 0);
+	sae->peer_commit_scalar = peer_scalar;
+	wpa_hexdump(MSG_DEBUG, "SAE: Peer commit-scalar",
+		    *pos, sae->tmp->prime_len);
+	*pos += sae->tmp->prime_len;
+
+	return WLAN_STATUS_SUCCESS;
+}
+
+
+static u16 sae_parse_commit_element_ecc(struct sae_data *sae, const u8 *pos,
+					const u8 *end)
+{
+	u8 prime[SAE_MAX_ECC_PRIME_LEN];
+
+	if (2 * sae->tmp->prime_len > end - pos) {
+		wpa_printf(MSG_DEBUG, "SAE: Not enough data for "
+			   "commit-element");
+		return WLAN_STATUS_UNSPECIFIED_FAILURE;
+	}
+
+	if (crypto_bignum_to_bin(sae->tmp->prime, prime, sizeof(prime),
+				 sae->tmp->prime_len) < 0)
+		return WLAN_STATUS_UNSPECIFIED_FAILURE;
+
+	/* element x and y coordinates < p */
+	if (os_memcmp(pos, prime, sae->tmp->prime_len) >= 0 ||
+	    os_memcmp(pos + sae->tmp->prime_len, prime,
+		      sae->tmp->prime_len) >= 0) {
+		wpa_printf(MSG_DEBUG, "SAE: Invalid coordinates in peer "
+			   "element");
+		return WLAN_STATUS_UNSPECIFIED_FAILURE;
+	}
+
+	wpa_hexdump(MSG_DEBUG, "SAE: Peer commit-element(x)",
+		    pos, sae->tmp->prime_len);
+	wpa_hexdump(MSG_DEBUG, "SAE: Peer commit-element(y)",
+		    pos + sae->tmp->prime_len, sae->tmp->prime_len);
+
+	crypto_ec_point_deinit(sae->tmp->peer_commit_element_ecc, 0);
+	sae->tmp->peer_commit_element_ecc =
+		crypto_ec_point_from_bin(sae->tmp->ec, pos);
+	if (sae->tmp->peer_commit_element_ecc == NULL)
+		return WLAN_STATUS_UNSPECIFIED_FAILURE;
+
+	if (!crypto_ec_point_is_on_curve(sae->tmp->ec,
+					 sae->tmp->peer_commit_element_ecc)) {
+		wpa_printf(MSG_DEBUG, "SAE: Peer element is not on curve");
+		return WLAN_STATUS_UNSPECIFIED_FAILURE;
+	}
+
+	return WLAN_STATUS_SUCCESS;
+}
+
+
+static u16 sae_parse_commit_element_ffc(struct sae_data *sae, const u8 *pos,
+					const u8 *end)
+{
+	struct crypto_bignum *res, *one;
+	const u8 one_bin[1] = { 0x01 };
+
+	if (sae->tmp->prime_len > end - pos) {
+		wpa_printf(MSG_DEBUG, "SAE: Not enough data for "
+			   "commit-element");
+		return WLAN_STATUS_UNSPECIFIED_FAILURE;
+	}
+	wpa_hexdump(MSG_DEBUG, "SAE: Peer commit-element", pos,
+		    sae->tmp->prime_len);
+
+	crypto_bignum_deinit(sae->tmp->peer_commit_element_ffc, 0);
+	sae->tmp->peer_commit_element_ffc =
+		crypto_bignum_init_set(pos, sae->tmp->prime_len);
+	if (sae->tmp->peer_commit_element_ffc == NULL)
+		return WLAN_STATUS_UNSPECIFIED_FAILURE;
+	/* 1 < element < p - 1 */
+	res = crypto_bignum_init();
+	one = crypto_bignum_init_set(one_bin, sizeof(one_bin));
+	if (!res || !one ||
+	    crypto_bignum_sub(sae->tmp->prime, one, res) ||
+	    crypto_bignum_is_zero(sae->tmp->peer_commit_element_ffc) ||
+	    crypto_bignum_is_one(sae->tmp->peer_commit_element_ffc) ||
+	    crypto_bignum_cmp(sae->tmp->peer_commit_element_ffc, res) >= 0) {
+		crypto_bignum_deinit(res, 0);
+		crypto_bignum_deinit(one, 0);
+		wpa_printf(MSG_DEBUG, "SAE: Invalid peer element");
+		return WLAN_STATUS_UNSPECIFIED_FAILURE;
+	}
+	crypto_bignum_deinit(one, 0);
+
+	/* scalar-op(r, ELEMENT) = 1 modulo p */
+	if (crypto_bignum_exptmod(sae->tmp->peer_commit_element_ffc,
+				  sae->tmp->order, sae->tmp->prime, res) < 0 ||
+	    !crypto_bignum_is_one(res)) {
+		wpa_printf(MSG_DEBUG, "SAE: Invalid peer element (scalar-op)");
+		crypto_bignum_deinit(res, 0);
+		return WLAN_STATUS_UNSPECIFIED_FAILURE;
+	}
+	crypto_bignum_deinit(res, 0);
+
+	return WLAN_STATUS_SUCCESS;
+}
+
+
+static u16 sae_parse_commit_element(struct sae_data *sae, const u8 *pos,
+				    const u8 *end)
+{
+	if (sae->tmp->dh)
+		return sae_parse_commit_element_ffc(sae, pos, end);
+	return sae_parse_commit_element_ecc(sae, pos, end);
+}
+
+
+u16 sae_parse_commit(struct sae_data *sae, const u8 *data, size_t len,
+		     const u8 **token, size_t *token_len, int *allowed_groups)
+{
+	const u8 *pos = data, *end = data + len;
+	u16 res;
+
+	/* Check Finite Cyclic Group */
+	if (end - pos < 2)
+		return WLAN_STATUS_UNSPECIFIED_FAILURE;
+	res = sae_group_allowed(sae, allowed_groups, WPA_GET_LE16(pos));
+	if (res != WLAN_STATUS_SUCCESS)
+		return res;
+	pos += 2;
+
+	/* Optional Anti-Clogging Token */
+	sae_parse_commit_token(sae, &pos, end, token, token_len);
+
+	/* commit-scalar */
+	res = sae_parse_commit_scalar(sae, &pos, end);
+	if (res != WLAN_STATUS_SUCCESS)
+		return res;
+
+	/* commit-element */
+	res = sae_parse_commit_element(sae, pos, end);
+	if (res != WLAN_STATUS_SUCCESS)
+		return res;
+
+	/*
+	 * Check whether peer-commit-scalar and PEER-COMMIT-ELEMENT are same as
+	 * the values we sent which would be evidence of a reflection attack.
+	 */
+	if (!sae->tmp->own_commit_scalar ||
+	    crypto_bignum_cmp(sae->tmp->own_commit_scalar,
+			      sae->peer_commit_scalar) != 0 ||
+	    (sae->tmp->dh &&
+	     (!sae->tmp->own_commit_element_ffc ||
+	      crypto_bignum_cmp(sae->tmp->own_commit_element_ffc,
+				sae->tmp->peer_commit_element_ffc) != 0)) ||
+	    (sae->tmp->ec &&
+	     (!sae->tmp->own_commit_element_ecc ||
+	      crypto_ec_point_cmp(sae->tmp->ec,
+				  sae->tmp->own_commit_element_ecc,
+				  sae->tmp->peer_commit_element_ecc) != 0)))
+		return WLAN_STATUS_SUCCESS; /* scalars/elements are different */
+
+	/*
+	 * This is a reflection attack - return special value to trigger caller
+	 * to silently discard the frame instead of replying with a specific
+	 * status code.
+	 */
+	return SAE_SILENTLY_DISCARD;
+}
+
+
+static void sae_cn_confirm(struct sae_data *sae, const u8 *sc,
+			   const struct crypto_bignum *scalar1,
+			   const u8 *element1, size_t element1_len,
+			   const struct crypto_bignum *scalar2,
+			   const u8 *element2, size_t element2_len,
+			   u8 *confirm)
+{
+	const u8 *addr[5];
+	size_t len[5];
+	u8 scalar_b1[SAE_MAX_PRIME_LEN], scalar_b2[SAE_MAX_PRIME_LEN];
+
+	/* Confirm
+	 * CN(key, X, Y, Z, ...) =
+	 *    HMAC-SHA256(key, D2OS(X) || D2OS(Y) || D2OS(Z) | ...)
+	 * confirm = CN(KCK, send-confirm, commit-scalar, COMMIT-ELEMENT,
+	 *              peer-commit-scalar, PEER-COMMIT-ELEMENT)
+	 * verifier = CN(KCK, peer-send-confirm, peer-commit-scalar,
+	 *               PEER-COMMIT-ELEMENT, commit-scalar, COMMIT-ELEMENT)
+	 */
+	addr[0] = sc;
+	len[0] = 2;
+	crypto_bignum_to_bin(scalar1, scalar_b1, sizeof(scalar_b1),
+			     sae->tmp->prime_len);
+	addr[1] = scalar_b1;
+	len[1] = sae->tmp->prime_len;
+	addr[2] = element1;
+	len[2] = element1_len;
+	crypto_bignum_to_bin(scalar2, scalar_b2, sizeof(scalar_b2),
+			     sae->tmp->prime_len);
+	addr[3] = scalar_b2;
+	len[3] = sae->tmp->prime_len;
+	addr[4] = element2;
+	len[4] = element2_len;
+	hmac_sha256_vector(sae->tmp->kck, sizeof(sae->tmp->kck), 5, addr, len,
+			   confirm);
+}
+
+
+static void sae_cn_confirm_ecc(struct sae_data *sae, const u8 *sc,
+			       const struct crypto_bignum *scalar1,
+			       const struct crypto_ec_point *element1,
+			       const struct crypto_bignum *scalar2,
+			       const struct crypto_ec_point *element2,
+			       u8 *confirm)
+{
+	u8 element_b1[2 * SAE_MAX_ECC_PRIME_LEN];
+	u8 element_b2[2 * SAE_MAX_ECC_PRIME_LEN];
+
+	crypto_ec_point_to_bin(sae->tmp->ec, element1, element_b1,
+			       element_b1 + sae->tmp->prime_len);
+	crypto_ec_point_to_bin(sae->tmp->ec, element2, element_b2,
+			       element_b2 + sae->tmp->prime_len);
+
+	sae_cn_confirm(sae, sc, scalar1, element_b1, 2 * sae->tmp->prime_len,
+		       scalar2, element_b2, 2 * sae->tmp->prime_len, confirm);
+}
+
+
+static void sae_cn_confirm_ffc(struct sae_data *sae, const u8 *sc,
+			       const struct crypto_bignum *scalar1,
+			       const struct crypto_bignum *element1,
+			       const struct crypto_bignum *scalar2,
+			       const struct crypto_bignum *element2,
+			       u8 *confirm)
+{
+	u8 element_b1[SAE_MAX_PRIME_LEN];
+	u8 element_b2[SAE_MAX_PRIME_LEN];
+
+	crypto_bignum_to_bin(element1, element_b1, sizeof(element_b1),
+			     sae->tmp->prime_len);
+	crypto_bignum_to_bin(element2, element_b2, sizeof(element_b2),
+			     sae->tmp->prime_len);
+
+	sae_cn_confirm(sae, sc, scalar1, element_b1, sae->tmp->prime_len,
+		       scalar2, element_b2, sae->tmp->prime_len, confirm);
+}
+
+
+void sae_write_confirm(struct sae_data *sae, struct wpabuf *buf)
+{
+	const u8 *sc;
+
+	if (sae->tmp == NULL)
+		return;
+
+	/* Send-Confirm */
+	sc = wpabuf_put(buf, 0);
+	wpabuf_put_le16(buf, sae->send_confirm);
+	sae->send_confirm++;
+
+	if (sae->tmp->ec)
+		sae_cn_confirm_ecc(sae, sc, sae->tmp->own_commit_scalar,
+				   sae->tmp->own_commit_element_ecc,
+				   sae->peer_commit_scalar,
+				   sae->tmp->peer_commit_element_ecc,
+				   wpabuf_put(buf, SHA256_MAC_LEN));
+	else
+		sae_cn_confirm_ffc(sae, sc, sae->tmp->own_commit_scalar,
+				   sae->tmp->own_commit_element_ffc,
+				   sae->peer_commit_scalar,
+				   sae->tmp->peer_commit_element_ffc,
+				   wpabuf_put(buf, SHA256_MAC_LEN));
+}
+
+
+int sae_check_confirm(struct sae_data *sae, const u8 *data, size_t len)
+{
+	u8 verifier[SHA256_MAC_LEN];
+
+	if (len < 2 + SHA256_MAC_LEN) {
+		wpa_printf(MSG_DEBUG, "SAE: Too short confirm message");
+		return -1;
+	}
+
+	wpa_printf(MSG_DEBUG, "SAE: peer-send-confirm %u", WPA_GET_LE16(data));
+
+	if (sae->tmp == NULL) {
+		wpa_printf(MSG_DEBUG, "SAE: Temporary data not yet available");
+		return -1;
+	}
+
+	if (sae->tmp->ec)
+		sae_cn_confirm_ecc(sae, data, sae->peer_commit_scalar,
+				   sae->tmp->peer_commit_element_ecc,
+				   sae->tmp->own_commit_scalar,
+				   sae->tmp->own_commit_element_ecc,
+				   verifier);
+	else
+		sae_cn_confirm_ffc(sae, data, sae->peer_commit_scalar,
+				   sae->tmp->peer_commit_element_ffc,
+				   sae->tmp->own_commit_scalar,
+				   sae->tmp->own_commit_element_ffc,
+				   verifier);
+
+	if (os_memcmp_const(verifier, data + 2, SHA256_MAC_LEN) != 0) {
+		wpa_printf(MSG_DEBUG, "SAE: Confirm mismatch");
+		wpa_hexdump(MSG_DEBUG, "SAE: Received confirm",
+			    data + 2, SHA256_MAC_LEN);
+		wpa_hexdump(MSG_DEBUG, "SAE: Calculated verifier",
+			    verifier, SHA256_MAC_LEN);
+		return -1;
+	}
+
+	return 0;
+}