/*
* Simultaneous authentication of equals
- * Copyright (c) 2012, Jouni Malinen <j@w1.fi>
+ * 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"
-/* TODO: move OpenSSL dependencies into crypto/crypto_openssl.c */
-#include <openssl/bn.h>
-#include <openssl/ec.h>
-#include <openssl/obj_mac.h>
#include "common.h"
+#include "utils/const_time.h"
+#include "crypto/crypto.h"
#include "crypto/sha256.h"
+#include "crypto/sha384.h"
+#include "crypto/sha512.h"
#include "crypto/random.h"
+#include "crypto/dh_groups.h"
#include "ieee802_11_defs.h"
+#include "dragonfly.h"
#include "sae.h"
-static const u8 group19_prime[] = {
- 0xFF, 0xFF, 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x01,
- 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
- 0x00, 0x00, 0x00, 0x00, 0xFF, 0xFF, 0xFF, 0xFF,
- 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF
-};
-
-static const u8 group19_order[] = {
- 0xFF, 0xFF, 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x00,
- 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
- 0xBC, 0xE6, 0xFA, 0xAD, 0xA7, 0x17, 0x9E, 0x84,
- 0xF3, 0xB9, 0xCA, 0xC2, 0xFC, 0x63, 0x25, 0x51
-};
-
-
-static int val_zero_or_one(const u8 *val, size_t len)
+int sae_set_group(struct sae_data *sae, int group)
{
- size_t i;
+ struct sae_temporary_data *tmp;
- for (i = 0; i < len - 1; i++) {
- if (val[i])
- return 0;
+#ifdef CONFIG_TESTING_OPTIONS
+ /* Allow all groups for testing purposes in non-production builds. */
+#else /* CONFIG_TESTING_OPTIONS */
+ if (!dragonfly_suitable_group(group, 0)) {
+ wpa_printf(MSG_DEBUG, "SAE: Reject unsuitable group %d", group);
+ return -1;
}
+#endif /* CONFIG_TESTING_OPTIONS */
- return val[len - 1] <= 1;
-}
-
+ sae_clear_data(sae);
+ tmp = sae->tmp = os_zalloc(sizeof(*tmp));
+ if (tmp == NULL)
+ return -1;
-static int val_zero(const u8 *val, size_t len)
-{
- size_t i;
- for (i = 0; i < len; i++) {
- if (val[i])
- return 0;
+ /* First, check if this is an ECC group */
+ tmp->ec = crypto_ec_init(group);
+ if (tmp->ec) {
+ wpa_printf(MSG_DEBUG, "SAE: Selecting supported ECC group %d",
+ group);
+ sae->group = group;
+ tmp->prime_len = crypto_ec_prime_len(tmp->ec);
+ tmp->prime = crypto_ec_get_prime(tmp->ec);
+ tmp->order_len = crypto_ec_order_len(tmp->ec);
+ tmp->order = crypto_ec_get_order(tmp->ec);
+ return 0;
}
- return 1;
-}
-
-
-static int sae_get_rand(u8 *val)
-{
- int iter = 0;
- do {
- if (random_get_bytes(val, sizeof(group19_prime)) < 0)
- return -1;
- if (iter++ > 100)
+ /* Not an ECC group, check FFC */
+ tmp->dh = dh_groups_get(group);
+ if (tmp->dh) {
+ wpa_printf(MSG_DEBUG, "SAE: Selecting supported FFC group %d",
+ group);
+ sae->group = group;
+ tmp->prime_len = tmp->dh->prime_len;
+ if (tmp->prime_len > SAE_MAX_PRIME_LEN) {
+ sae_clear_data(sae);
return -1;
- } while (os_memcmp(val, group19_order, sizeof(group19_prime)) >= 0 ||
- val_zero_or_one(val, sizeof(group19_prime)));
-
- return 0;
-}
-
+ }
-static EC_POINT * alloc_elem(EC_GROUP *group, const u8 *val, size_t len)
-{
- BIGNUM *x, *y;
- EC_POINT *elem;
+ 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;
- x = BN_bin2bn(val, len, NULL);
- y = BN_bin2bn(val + len, len, NULL);
- elem = EC_POINT_new(group);
- if (x == NULL || y == NULL || elem == NULL) {
- BN_free(x);
- BN_free(y);
- EC_POINT_free(elem);
- return NULL;
- }
+ tmp->order_len = tmp->dh->order_len;
+ 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;
- if (!EC_POINT_set_affine_coordinates_GFp(group, elem, x, y, NULL)) {
- EC_POINT_free(elem);
- elem = NULL;
+ return 0;
}
- BN_free(x);
- BN_free(y);
-
- return elem;
+ /* Unsupported group */
+ wpa_printf(MSG_DEBUG,
+ "SAE: Group %d not supported by the crypto library", group);
+ return -1;
}
-static void sae_bn_to_bin(const BIGNUM *bn, u8 *bin, size_t len)
+void sae_clear_temp_data(struct sae_data *sae)
{
- int offset = len - BN_num_bytes(bn);
- os_memset(bin, 0, offset);
- BN_bn2bin(bn, bin + offset);
+ 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);
+ wpabuf_free(tmp->own_rejected_groups);
+ wpabuf_free(tmp->peer_rejected_groups);
+ os_free(tmp->pw_id);
+ bin_clear_free(tmp, sizeof(*tmp));
+ sae->tmp = NULL;
}
-static int sae_ec_point_to_bin(BN_CTX *bnctx, EC_GROUP *group, EC_POINT *point,
- u8 *bin)
+void sae_clear_data(struct sae_data *sae)
{
- BIGNUM *x, *y;
- int ret = -1;
-
- x = BN_new();
- y = BN_new();
-
- if (x && y &&
- EC_POINT_get_affine_coordinates_GFp(group, point, x, y, bnctx)) {
- sae_bn_to_bin(x, bin, 32);
- sae_bn_to_bin(y, bin + 32, 32);
- ret = 0;
- }
-
- BN_free(x);
- BN_free(y);
- return ret;
+ if (sae == NULL)
+ return;
+ sae_clear_temp_data(sae);
+ crypto_bignum_deinit(sae->peer_commit_scalar, 0);
+ crypto_bignum_deinit(sae->peer_commit_scalar_accepted, 0);
+ os_memset(sae, 0, sizeof(*sae));
}
}
-static int sae_test_pwd_seed(BN_CTX *bnctx, EC_GROUP *group, const u8 *pwd_seed,
- EC_POINT *pwe, u8 *pwe_bin)
+static int sae_test_pwd_seed_ecc(struct sae_data *sae, const u8 *pwd_seed,
+ const u8 *prime, const u8 *qr, const u8 *qnr,
+ u8 *pwd_value)
{
- u8 pwd_value[32];
- BIGNUM *x;
- int y_bit;
+ struct crypto_bignum *y_sqr, *x_cand;
+ int res;
+ size_t bits;
+ int cmp_prime;
+ unsigned int in_range;
- wpa_hexdump_key(MSG_DEBUG, "SAE: pwd-seed", pwd_seed, 32);
+ wpa_hexdump_key(MSG_DEBUG, "SAE: pwd-seed", pwd_seed, SHA256_MAC_LEN);
/* pwd-value = KDF-z(pwd-seed, "SAE Hunting and Pecking", p) */
- sha256_prf(pwd_seed, 32, "SAE Hunting and Pecking",
- group19_prime, sizeof(group19_prime),
- pwd_value, sizeof(pwd_value));
+ 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, sae->tmp->prime_len, 8 - bits % 8);
wpa_hexdump_key(MSG_DEBUG, "SAE: pwd-value",
- pwd_value, sizeof(pwd_value));
+ pwd_value, sae->tmp->prime_len);
+
+ cmp_prime = const_time_memcmp(pwd_value, prime, sae->tmp->prime_len);
+ /* Create a const_time mask for selection based on prf result
+ * being smaller than prime. */
+ in_range = const_time_fill_msb((unsigned int) cmp_prime);
+ /* The algorithm description would skip the next steps if
+ * cmp_prime >= 0 (reutnr 0 here), but go through them regardless to
+ * minimize externally observable differences in behavior. */
+
+ 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);
+ crypto_bignum_deinit(x_cand, 1);
+ if (!y_sqr)
+ return -1;
+
+ res = dragonfly_is_quadratic_residue_blind(sae->tmp->ec, qr, qnr,
+ y_sqr);
+ crypto_bignum_deinit(y_sqr, 1);
+ if (res < 0)
+ return res;
+ return const_time_select_int(in_range, res, 0);
+}
- if (os_memcmp(pwd_value, group19_prime, sizeof(group19_prime)) >= 0)
- return 0;
- y_bit = pwd_seed[SHA256_MAC_LEN - 1] & 0x01;
+/* Returns -1 on fatal failure, 0 if PWE cannot be derived from the provided
+ * pwd-seed, or 1 if a valid PWE was derived from pwd-seed. */
+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 = NULL;
+ int res, is_val;
+ u8 pwd_value_valid;
+
+ wpa_hexdump_key(MSG_DEBUG, "SAE: pwd-seed", pwd_seed, SHA256_MAC_LEN);
- x = BN_bin2bn(pwd_value, sizeof(pwd_value), NULL);
- if (x == NULL)
+ /* 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;
- if (!EC_POINT_set_compressed_coordinates_GFp(group, pwe, x, y_bit,
- bnctx) ||
- !EC_POINT_is_on_curve(group, pwe, bnctx)) {
- BN_free(x);
- wpa_printf(MSG_DEBUG, "SAE: No solution found");
- return 0;
+ wpa_hexdump_key(MSG_DEBUG, "SAE: pwd-value", pwd_value,
+ sae->tmp->prime_len);
+
+ /* Check whether pwd-value < p */
+ res = const_time_memcmp(pwd_value, sae->tmp->dh->prime,
+ sae->tmp->prime_len);
+ /* pwd-value >= p is invalid, so res is < 0 for the valid cases and
+ * the negative sign can be used to fill the mask for constant time
+ * selection */
+ pwd_value_valid = const_time_fill_msb(res);
+
+ /* If pwd-value >= p, force pwd-value to be < p and perform the
+ * calculations anyway to hide timing difference. The derived PWE will
+ * be ignored in that case. */
+ pwd_value[0] = const_time_select_u8(pwd_value_valid, pwd_value[0], 0);
+
+ /* PWE = pwd-value^((p-1)/r) modulo p */
+
+ res = -1;
+ a = crypto_bignum_init_set(pwd_value, sae->tmp->prime_len);
+ if (!a)
+ goto fail;
+
+ /* This is an optimization based on the used group that does not depend
+ * on the password in any way, so it is fine to use separate branches
+ * for this step without constant time operations. */
+ 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)
+ goto fail;
}
- BN_free(x);
- wpa_printf(MSG_DEBUG, "SAE: PWE found");
+ if (!b)
+ goto fail;
+
+ res = crypto_bignum_exptmod(a, b, sae->tmp->prime, pwe);
+ if (res < 0)
+ goto fail;
- if (sae_ec_point_to_bin(bnctx, group, pwe, pwe_bin) < 0)
- return -1;
+ /* There were no fatal errors in calculations, so determine the return
+ * value using constant time operations. We get here for number of
+ * invalid cases which are cleared here after having performed all the
+ * computation. PWE is valid if pwd-value was less than prime and
+ * PWE > 1. Start with pwd-value check first and then use constant time
+ * operations to clear res to 0 if PWE is 0 or 1.
+ */
+ res = const_time_select_u8(pwd_value_valid, 1, 0);
+ is_val = crypto_bignum_is_zero(pwe);
+ res = const_time_select_u8(const_time_is_zero(is_val), res, 0);
+ is_val = crypto_bignum_is_one(pwe);
+ res = const_time_select_u8(const_time_is_zero(is_val), res, 0);
- wpa_hexdump_key(MSG_DEBUG, "SAE: PWE x", pwe_bin, 32);
- wpa_hexdump_key(MSG_DEBUG, "SAE: PWE y", pwe_bin + 32, 32);
- return 1;
+fail:
+ crypto_bignum_deinit(a, 1);
+ crypto_bignum_deinit(b, 1);
+ return res;
}
-static int sae_derive_pwe(BN_CTX *bnctx, EC_GROUP *group, const u8 *addr1,
- const u8 *addr2, const u8 *password,
- size_t password_len, EC_POINT *pwe, u8 *pwe_bin)
+static int sae_derive_pwe_ecc(struct sae_data *sae, const u8 *addr1,
+ const u8 *addr2, const u8 *password,
+ size_t password_len, const char *identifier)
{
- u8 counter, k = 4;
+ u8 counter, k;
u8 addrs[2 * ETH_ALEN];
- const u8 *addr[2];
- size_t len[2];
- int found = 0;
- EC_POINT *pwe_tmp;
- u8 pwe_bin_tmp[2 * 32];
+ const u8 *addr[3];
+ size_t len[3];
+ size_t num_elem;
+ u8 *dummy_password, *tmp_password;
+ int pwd_seed_odd = 0;
+ u8 prime[SAE_MAX_ECC_PRIME_LEN];
+ size_t prime_len;
+ struct crypto_bignum *x = NULL, *qr = NULL, *qnr = NULL;
+ u8 x_bin[SAE_MAX_ECC_PRIME_LEN];
+ u8 x_cand_bin[SAE_MAX_ECC_PRIME_LEN];
+ u8 qr_bin[SAE_MAX_ECC_PRIME_LEN];
+ u8 qnr_bin[SAE_MAX_ECC_PRIME_LEN];
+ int res = -1;
+ u8 found = 0; /* 0 (false) or 0xff (true) to be used as const_time_*
+ * mask */
+
+ os_memset(x_bin, 0, sizeof(x_bin));
+
+ dummy_password = os_malloc(password_len);
+ tmp_password = os_malloc(password_len);
+ if (!dummy_password || !tmp_password ||
+ random_get_bytes(dummy_password, password_len) < 0)
+ goto fail;
- pwe_tmp = EC_POINT_new(group);
- if (pwe_tmp == NULL)
- return -1;
+ prime_len = sae->tmp->prime_len;
+ if (crypto_bignum_to_bin(sae->tmp->prime, prime, sizeof(prime),
+ prime_len) < 0)
+ goto fail;
+
+ /*
+ * Create a random quadratic residue (qr) and quadratic non-residue
+ * (qnr) modulo p for blinding purposes during the loop.
+ */
+ if (dragonfly_get_random_qr_qnr(sae->tmp->prime, &qr, &qnr) < 0 ||
+ crypto_bignum_to_bin(qr, qr_bin, sizeof(qr_bin), prime_len) < 0 ||
+ crypto_bignum_to_bin(qnr, qnr_bin, sizeof(qnr_bin), prime_len) < 0)
+ goto fail;
wpa_hexdump_ascii_key(MSG_DEBUG, "SAE: password",
password, password_len);
+ if (identifier)
+ wpa_printf(MSG_DEBUG, "SAE: password identifier: %s",
+ identifier);
/*
* H(salt, ikm) = HMAC-SHA256(salt, ikm)
+ * base = password [|| identifier]
* pwd-seed = H(MAX(STA-A-MAC, STA-B-MAC) || MIN(STA-A-MAC, STA-B-MAC),
- * password || counter)
+ * base || counter)
*/
sae_pwd_seed_key(addr1, addr2, addrs);
- addr[0] = password;
+ addr[0] = tmp_password;
len[0] = password_len;
- addr[1] = &counter;
- len[1] = sizeof(counter);
+ num_elem = 1;
+ if (identifier) {
+ addr[num_elem] = (const u8 *) identifier;
+ len[num_elem] = os_strlen(identifier);
+ num_elem++;
+ }
+ addr[num_elem] = &counter;
+ len[num_elem] = sizeof(counter);
+ num_elem++;
/*
* 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 || !found; counter++) {
- u8 pwd_seed[SHA256_MAC_LEN];
- int res;
+ k = dragonfly_min_pwe_loop_iter(sae->group);
- 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(bnctx, group, pwd_seed,
- found ? pwe_tmp : pwe,
- found ? pwe_bin_tmp : pwe_bin);
- if (res < 0)
- break;
- if (res == 0)
- continue;
- if (found) {
- wpa_printf(MSG_DEBUG, "SAE: Ignore this PWE (one was "
- "already selected)");
- } else {
- wpa_printf(MSG_DEBUG, "SAE: Use this PWE");
- found = 1;
- }
+ for (counter = 1; counter <= k || !found; counter++) {
+ u8 pwd_seed[SHA256_MAC_LEN];
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 = %03u", counter);
+ const_time_select_bin(found, dummy_password, password,
+ password_len, tmp_password);
+ if (hmac_sha256_vector(addrs, sizeof(addrs), num_elem,
+ addr, len, pwd_seed) < 0)
+ break;
+
+ res = sae_test_pwd_seed_ecc(sae, pwd_seed,
+ prime, qr_bin, qnr_bin, x_cand_bin);
+ const_time_select_bin(found, x_bin, x_cand_bin, prime_len,
+ x_bin);
+ pwd_seed_odd = const_time_select_u8(
+ found, pwd_seed_odd,
+ pwd_seed[SHA256_MAC_LEN - 1] & 0x01);
+ os_memset(pwd_seed, 0, sizeof(pwd_seed));
+ if (res < 0)
+ goto fail;
+ /* Need to minimize differences in handling res == 0 and 1 here
+ * to avoid differences in timing and instruction cache access,
+ * so use const_time_select_*() to make local copies of the
+ * values based on whether this loop iteration was the one that
+ * found the pwd-seed/x. */
+
+ /* found is 0 or 0xff here and res is 0 or 1. Bitwise OR of them
+ * (with res converted to 0/0xff) handles this in constant time.
+ */
+ found |= res * 0xff;
+ wpa_printf(MSG_DEBUG, "SAE: pwd-seed result %d found=0x%02x",
+ res, found);
+ }
+
+ if (!found) {
+ wpa_printf(MSG_DEBUG, "SAE: Could not generate PWE");
+ res = -1;
+ goto fail;
}
- EC_POINT_clear_free(pwe_tmp);
+ x = crypto_bignum_init_set(x_bin, prime_len);
+ if (!x) {
+ 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);
+ 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");
+ }
- return found ? 0 : -1;
+fail:
+ crypto_bignum_deinit(qr, 0);
+ crypto_bignum_deinit(qnr, 0);
+ os_free(dummy_password);
+ bin_clear_free(tmp_password, password_len);
+ crypto_bignum_deinit(x, 1);
+ os_memset(x_bin, 0, sizeof(x_bin));
+ os_memset(x_cand_bin, 0, sizeof(x_cand_bin));
+
+ return res;
}
-static int sae_derive_commit(struct sae_data *sae, BN_CTX *bnctx,
- EC_GROUP *group, EC_POINT *pwe)
+static int sae_derive_pwe_ffc(struct sae_data *sae, const u8 *addr1,
+ const u8 *addr2, const u8 *password,
+ size_t password_len, const char *identifier)
{
- BIGNUM *x, *bn_rand, *bn_mask, *order;
- EC_POINT *elem;
- u8 mask[32];
- int ret = -1;
+ u8 counter, k, sel_counter = 0;
+ u8 addrs[2 * ETH_ALEN];
+ const u8 *addr[3];
+ size_t len[3];
+ size_t num_elem;
+ u8 found = 0; /* 0 (false) or 0xff (true) to be used as const_time_*
+ * mask */
+ u8 mask;
+ struct crypto_bignum *pwe;
+ size_t prime_len = sae->tmp->prime_len * 8;
+ u8 *pwe_buf;
+
+ crypto_bignum_deinit(sae->tmp->pwe_ffc, 1);
+ sae->tmp->pwe_ffc = NULL;
+
+ /* Allocate a buffer to maintain selected and candidate PWE for constant
+ * time selection. */
+ pwe_buf = os_zalloc(prime_len * 2);
+ pwe = crypto_bignum_init();
+ if (!pwe_buf || !pwe)
+ goto fail;
- if (sae_get_rand(sae->sae_rand) < 0 || sae_get_rand(mask) < 0)
- return -1;
- wpa_hexdump_key(MSG_DEBUG, "SAE: rand",
- sae->sae_rand, sizeof(sae->sae_rand));
- wpa_hexdump_key(MSG_DEBUG, "SAE: mask", mask, sizeof(mask));
-
- x = BN_new();
- bn_rand = BN_bin2bn(sae->sae_rand, 32, NULL);
- bn_mask = BN_bin2bn(mask, sizeof(mask), NULL);
- order = BN_bin2bn(group19_order, sizeof(group19_order), NULL);
- elem = EC_POINT_new(group);
- if (x == NULL || bn_rand == NULL || bn_mask == NULL || order == NULL ||
- elem == NULL)
- goto fail;
-
- /* commit-scalar = (rand + mask) modulo r */
- BN_add(x, bn_rand, bn_mask);
- BN_mod(x, x, order, bnctx);
- sae_bn_to_bin(x, sae->own_commit_scalar, 32);
- wpa_hexdump(MSG_DEBUG, "SAE: commit-scalar",
- sae->own_commit_scalar, 32);
+ wpa_hexdump_ascii_key(MSG_DEBUG, "SAE: password",
+ password, password_len);
- /* COMMIT-ELEMENT = inverse(scalar-op(mask, PWE)) */
- if (!EC_POINT_mul(group, elem, NULL, pwe, bn_mask, bnctx) ||
- !EC_POINT_invert(group, elem, bnctx) ||
- sae_ec_point_to_bin(bnctx, group, elem, sae->own_commit_element) <
- 0)
- goto fail;
+ /*
+ * 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 [|| identifier] || counter)
+ */
+ sae_pwd_seed_key(addr1, addr2, addrs);
+
+ addr[0] = password;
+ len[0] = password_len;
+ num_elem = 1;
+ if (identifier) {
+ addr[num_elem] = (const u8 *) identifier;
+ len[num_elem] = os_strlen(identifier);
+ num_elem++;
+ }
+ addr[num_elem] = &counter;
+ len[num_elem] = sizeof(counter);
+ num_elem++;
- wpa_hexdump(MSG_DEBUG, "SAE: commit-element x",
- sae->own_commit_element, 32);
- wpa_hexdump(MSG_DEBUG, "SAE: commit-element y",
- sae->own_commit_element + 32, 32);
+ k = dragonfly_min_pwe_loop_iter(sae->group);
- ret = 0;
+ for (counter = 1; counter <= k || !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 = %02u", counter);
+ if (hmac_sha256_vector(addrs, sizeof(addrs), num_elem,
+ addr, len, pwd_seed) < 0)
+ break;
+ res = sae_test_pwd_seed_ffc(sae, pwd_seed, pwe);
+ /* res is -1 for fatal failure, 0 if a valid PWE was not found,
+ * or 1 if a valid PWE was found. */
+ if (res < 0)
+ break;
+ /* Store the candidate PWE into the second half of pwe_buf and
+ * the selected PWE in the beginning of pwe_buf using constant
+ * time selection. */
+ if (crypto_bignum_to_bin(pwe, pwe_buf + prime_len, prime_len,
+ prime_len) < 0)
+ break;
+ const_time_select_bin(found, pwe_buf, pwe_buf + prime_len,
+ prime_len, pwe_buf);
+ sel_counter = const_time_select_u8(found, sel_counter, counter);
+ mask = const_time_eq_u8(res, 1);
+ found = const_time_select_u8(found, found, mask);
+ }
+
+ if (!found)
+ goto fail;
+
+ wpa_printf(MSG_DEBUG, "SAE: Use PWE from counter = %02u", sel_counter);
+ sae->tmp->pwe_ffc = crypto_bignum_init_set(pwe_buf, prime_len);
fail:
- EC_POINT_free(elem);
- BN_free(order);
- BN_clear_free(bn_mask);
- os_memset(mask, 0, sizeof(mask));
- BN_clear_free(bn_rand);
- BN_clear_free(x);
- return ret;
+ crypto_bignum_deinit(pwe, 1);
+ bin_clear_free(pwe_buf, prime_len * 2);
+ return sae->tmp->pwe_ffc ? 0 : -1;
}
-int sae_prepare_commit(const u8 *addr1, const u8 *addr2,
- const u8 *password, size_t password_len,
- struct sae_data *sae)
-{
- BN_CTX *bnctx;
- EC_POINT *pwe;
- EC_GROUP *group;
- int ret = 0;
-
- bnctx = BN_CTX_new();
- group = EC_GROUP_new_by_curve_name(NID_X9_62_prime256v1);
- pwe = EC_POINT_new(group);
- if (bnctx == NULL || group == NULL || pwe == NULL ||
- sae_derive_pwe(bnctx, group, addr1, addr2, password, password_len,
- pwe, sae->pwe) < 0 ||
- sae_derive_commit(sae, bnctx, group, pwe) < 0)
- ret = -1;
-
- EC_POINT_clear_free(pwe);
- EC_GROUP_free(group);
- BN_CTX_free(bnctx);
+static int hkdf_extract(size_t hash_len, const u8 *salt, size_t salt_len,
+ size_t num_elem, const u8 *addr[], const size_t len[],
+ u8 *prk)
+{
+ if (hash_len == 32)
+ return hmac_sha256_vector(salt, salt_len, num_elem, addr, len,
+ prk);
+#ifdef CONFIG_SHA384
+ if (hash_len == 48)
+ return hmac_sha384_vector(salt, salt_len, num_elem, addr, len,
+ prk);
+#endif /* CONFIG_SHA384 */
+#ifdef CONFIG_SHA512
+ if (hash_len == 64)
+ return hmac_sha512_vector(salt, salt_len, num_elem, addr, len,
+ prk);
+#endif /* CONFIG_SHA512 */
+ return -1;
+}
- return ret;
+
+static int hkdf_expand(size_t hash_len, const u8 *prk, size_t prk_len,
+ const char *info, u8 *okm, size_t okm_len)
+{
+ size_t info_len = os_strlen(info);
+
+ if (hash_len == 32)
+ return hmac_sha256_kdf(prk, prk_len, NULL,
+ (const u8 *) info, info_len,
+ okm, okm_len);
+#ifdef CONFIG_SHA384
+ if (hash_len == 48)
+ return hmac_sha384_kdf(prk, prk_len, NULL,
+ (const u8 *) info, info_len,
+ okm, okm_len);
+#endif /* CONFIG_SHA384 */
+#ifdef CONFIG_SHA512
+ if (hash_len == 64)
+ return hmac_sha512_kdf(prk, prk_len, NULL,
+ (const u8 *) info, info_len,
+ okm, okm_len);
+#endif /* CONFIG_SHA512 */
+ return -1;
}
-static int sae_check_peer_commit(struct sae_data *sae)
+static int sswu_curve_param(int group, int *z)
{
- /* 0 < scalar < r */
- if (val_zero(sae->peer_commit_scalar, 32) ||
- os_memcmp(sae->peer_commit_scalar, group19_order,
- sizeof(group19_prime)) >= 0) {
- wpa_printf(MSG_DEBUG, "SAE: Invalid peer scalar");
- return -1;
+ switch (group) {
+ case 19:
+ *z = -10;
+ return 0;
+ case 20:
+ *z = -12;
+ return 0;
+ case 21:
+ *z = -4;
+ return 0;
+ case 25:
+ case 29:
+ *z = -5;
+ return 0;
+ case 26:
+ *z = 31;
+ return 0;
+ case 28:
+ *z = -2;
+ return 0;
+ case 30:
+ *z = 7;
+ return 0;
}
- /* element x and y coordinates < p */
- if (os_memcmp(sae->peer_commit_element, group19_prime,
- sizeof(group19_prime)) >= 0 ||
- os_memcmp(sae->peer_commit_element + 32, group19_prime,
- sizeof(group19_prime)) >= 0) {
- wpa_printf(MSG_DEBUG, "SAE: Invalid coordinates in peer "
- "element");
- return -1;
- }
+ return -1;
+}
- return 0;
+
+static void debug_print_bignum(const char *title, const struct crypto_bignum *a,
+ size_t prime_len)
+{
+ u8 *bin;
+
+ bin = os_malloc(prime_len);
+ if (bin && crypto_bignum_to_bin(a, bin, prime_len, prime_len) >= 0)
+ wpa_hexdump_key(MSG_DEBUG, title, bin, prime_len);
+ else
+ wpa_printf(MSG_DEBUG, "Could not print bignum (%s)", title);
+ bin_clear_free(bin, prime_len);
}
-static int sae_derive_k(struct sae_data *sae, u8 *k, BN_CTX *bnctx,
- EC_GROUP *group)
+static struct crypto_ec_point * sswu(struct crypto_ec *ec, int group,
+ const struct crypto_bignum *u)
{
- EC_POINT *pwe, *peer_elem, *K;
- BIGNUM *k_bn, *rand_bn, *peer_scalar;
- int ret = -1;
+ int z_int;
+ const struct crypto_bignum *a, *b, *prime;
+ struct crypto_bignum *u2, *t1, *t2, *z, *t, *zero, *one, *two, *three,
+ *x1a, *x1b, *y = NULL;
+ struct crypto_bignum *x1 = NULL, *x2, *gx1, *gx2, *v = NULL;
+ unsigned int m_is_zero, is_qr, is_eq;
+ size_t prime_len;
+ u8 bin[SAE_MAX_ECC_PRIME_LEN];
+ u8 bin1[SAE_MAX_ECC_PRIME_LEN];
+ u8 bin2[SAE_MAX_ECC_PRIME_LEN];
+ u8 x_y[2 * SAE_MAX_ECC_PRIME_LEN];
+ struct crypto_ec_point *p = NULL;
+
+ if (sswu_curve_param(group, &z_int) < 0)
+ return NULL;
- pwe = alloc_elem(group, sae->pwe, 32);
- peer_scalar = BN_bin2bn(sae->peer_commit_scalar, 32, NULL);
- peer_elem = alloc_elem(group, sae->peer_commit_element, 32);
- K = EC_POINT_new(group);
- k_bn = BN_new();
- rand_bn = BN_bin2bn(sae->sae_rand, 32, NULL);
- if (pwe == NULL || peer_elem == NULL || peer_scalar == NULL ||
- K == NULL || k_bn == NULL || rand_bn == NULL)
+ prime = crypto_ec_get_prime(ec);
+ prime_len = crypto_ec_prime_len(ec);
+ a = crypto_ec_get_a(ec);
+ b = crypto_ec_get_b(ec);
+
+ u2 = crypto_bignum_init();
+ t1 = crypto_bignum_init();
+ t2 = crypto_bignum_init();
+ z = crypto_bignum_init_uint(abs(z_int));
+ t = crypto_bignum_init();
+ zero = crypto_bignum_init_uint(0);
+ one = crypto_bignum_init_uint(1);
+ two = crypto_bignum_init_uint(2);
+ three = crypto_bignum_init_uint(3);
+ x1a = crypto_bignum_init();
+ x1b = crypto_bignum_init();
+ x2 = crypto_bignum_init();
+ gx1 = crypto_bignum_init();
+ gx2 = crypto_bignum_init();
+ if (!u2 || !t1 || !t2 || !z || !t || !zero || !one || !two || !three ||
+ !x1a || !x1b || !x2 || !gx1 || !gx2)
goto fail;
- if (!EC_POINT_is_on_curve(group, peer_elem, NULL)) {
- wpa_printf(MSG_DEBUG, "SAE: Peer element is not on curve");
+ if (z_int < 0 && crypto_bignum_sub(prime, z, z) < 0)
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)
- */
+ /* m = z^2 * u^4 + z * u^2 */
+ /* --> tmp = z * u^2, m = tmp^2 + tmp */
+
+ /* u2 = u^2
+ * t1 = z * u2
+ * t2 = t1^2
+ * m = t1 = t1 + t2 */
+ if (crypto_bignum_sqrmod(u, prime, u2) < 0 ||
+ crypto_bignum_mulmod(z, u2, prime, t1) < 0 ||
+ crypto_bignum_sqrmod(t1, prime, t2) < 0 ||
+ crypto_bignum_addmod(t1, t2, prime, t1) < 0)
+ goto fail;
+ debug_print_bignum("SSWU: m", t1, prime_len);
+
+ /* l = CEQ(m, 0)
+ * t = CSEL(l, 0, inverse(m); where inverse(x) is calculated as
+ * x^(p-2) modulo p which will handle m == 0 case correctly */
+ /* TODO: Make sure crypto_bignum_is_zero() is constant time */
+ m_is_zero = const_time_eq(crypto_bignum_is_zero(t1), 1);
+ /* t = m^(p-2) modulo p */
+ if (crypto_bignum_sub(prime, two, t2) < 0 ||
+ crypto_bignum_exptmod(t1, t2, prime, t) < 0)
+ goto fail;
+ debug_print_bignum("SSWU: t", t, prime_len);
- if (!EC_POINT_mul(group, K, NULL, pwe, peer_scalar, bnctx) ||
- !EC_POINT_add(group, K, K, peer_elem, bnctx) ||
- !EC_POINT_mul(group, K, NULL, K, rand_bn, bnctx) ||
- EC_POINT_is_at_infinity(group, K) ||
- !EC_POINT_get_affine_coordinates_GFp(group, K, k_bn, NULL, bnctx)) {
- wpa_printf(MSG_DEBUG, "SAE: Failed to calculate K and k");
+ /* b / (z * a) */
+ if (crypto_bignum_mulmod(z, a, prime, t1) < 0 ||
+ crypto_bignum_inverse(t1, prime, t1) < 0 ||
+ crypto_bignum_mulmod(b, t1, prime, x1a) < 0)
goto fail;
- }
+ debug_print_bignum("SSWU: x1a = b / (z * a)", x1a, prime_len);
+
+ /* (-b/a) * (1 + t) */
+ if (crypto_bignum_sub(prime, b, t1) < 0 ||
+ crypto_bignum_inverse(a, prime, t2) < 0 ||
+ crypto_bignum_mulmod(t1, t2, prime, t1) < 0 ||
+ crypto_bignum_addmod(one, t, prime, t2) < 0 ||
+ crypto_bignum_mulmod(t1, t2, prime, x1b) < 0)
+ goto fail;
+ debug_print_bignum("SSWU: x1b = (-b/a) * (1 + t)", x1b, prime_len);
- sae_bn_to_bin(k_bn, k, 32);
- wpa_hexdump_key(MSG_DEBUG, "SAE: k", k, 32);
+ /* x1 = CSEL(CEQ(m, 0), x1a, x1b) */
+ if (crypto_bignum_to_bin(x1a, bin1, sizeof(bin1), prime_len) < 0 ||
+ crypto_bignum_to_bin(x1b, bin2, sizeof(bin2), prime_len) < 0)
+ goto fail;
+ const_time_select_bin(m_is_zero, bin1, bin2, prime_len, bin);
+ x1 = crypto_bignum_init_set(bin, prime_len);
+ debug_print_bignum("SSWU: x1 = CSEL(l, x1a, x1b)", x1, prime_len);
+
+ /* gx1 = x1^3 + a * x1 + b */
+ if (crypto_bignum_exptmod(x1, three, prime, t1) < 0 ||
+ crypto_bignum_mulmod(a, x1, prime, t2) < 0 ||
+ crypto_bignum_addmod(t1, t2, prime, t1) < 0 ||
+ crypto_bignum_addmod(t1, b, prime, gx1) < 0)
+ goto fail;
+ debug_print_bignum("SSWU: gx1 = x1^3 + a * x1 + b", gx1, prime_len);
- ret = 0;
-fail:
- EC_POINT_free(pwe);
- EC_POINT_free(peer_elem);
- EC_POINT_clear_free(K);
- BN_free(k_bn);
- BN_free(rand_bn);
- return ret;
-}
+ /* x2 = z * u^2 * x1 */
+ if (crypto_bignum_mulmod(z, u2, prime, t1) < 0 ||
+ crypto_bignum_mulmod(t1, x1, prime, x2) < 0)
+ goto fail;
+ debug_print_bignum("SSWU: x2 = z * u^2 * x1", x2, prime_len);
+ /* gx2 = x2^3 + a * x2 + b */
+ if (crypto_bignum_exptmod(x2, three, prime, t1) < 0 ||
+ crypto_bignum_mulmod(a, x2, prime, t2) < 0 ||
+ crypto_bignum_addmod(t1, t2, prime, t1) < 0 ||
+ crypto_bignum_addmod(t1, b, prime, gx2) < 0)
+ goto fail;
+ debug_print_bignum("SSWU: gx2 = x2^3 + a * x2 + b", gx2, prime_len);
-static int sae_derive_keys(struct sae_data *sae, const u8 *k, BN_CTX *bnctx)
-{
- u8 null_key[32], val[32];
- u8 keyseed[SHA256_MAC_LEN];
- u8 keys[32 + 32];
- BIGNUM *order, *own_scalar, *peer_scalar, *tmp;
- int ret = -1;
+ /* l = gx1 is a quadratic residue modulo p
+ * --> gx1^((p-1)/2) modulo p is zero or one */
+ if (crypto_bignum_sub(prime, one, t1) < 0 ||
+ crypto_bignum_rshift(t1, 1, t1) < 0 ||
+ crypto_bignum_exptmod(gx1, t1, prime, t1) < 0)
+ goto fail;
+ debug_print_bignum("SSWU: gx1^((p-1)/2) modulo p", t1, prime_len);
+ is_qr = const_time_eq(crypto_bignum_is_zero(t1) |
+ crypto_bignum_is_one(t1), 1);
- order = BN_bin2bn(group19_order, sizeof(group19_order), NULL);
- own_scalar = BN_bin2bn(sae->own_commit_scalar, 32, NULL);
- peer_scalar = BN_bin2bn(sae->peer_commit_scalar, 32, NULL);
- tmp = BN_new();
- if (order == NULL || own_scalar == NULL || peer_scalar == NULL ||
- tmp == NULL)
+ /* v = CSEL(l, gx1, gx2) */
+ if (crypto_bignum_to_bin(gx1, bin1, sizeof(bin1), prime_len) < 0 ||
+ crypto_bignum_to_bin(gx2, bin2, sizeof(bin2), prime_len) < 0)
goto fail;
+ const_time_select_bin(is_qr, bin1, bin2, prime_len, bin);
+ v = crypto_bignum_init_set(bin, prime_len);
+ debug_print_bignum("SSWU: v = CSEL(l, gx1, gx2)", v, prime_len);
- /* 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)
- */
+ /* x = CSEL(l, x1, x2) */
+ if (crypto_bignum_to_bin(x1, bin1, sizeof(bin1), prime_len) < 0 ||
+ crypto_bignum_to_bin(x2, bin2, sizeof(bin2), prime_len) < 0)
+ goto fail;
+ const_time_select_bin(is_qr, bin1, bin2, prime_len, x_y);
+ wpa_hexdump_key(MSG_DEBUG, "SSWU: x = CSEL(l, x1, x2)", x_y, prime_len);
+
+ /* y = sqrt(v)
+ * For prime p such that p = 3 mod 4 --> v^((p+1)/4) */
+ if (crypto_bignum_to_bin(prime, bin1, sizeof(bin1), prime_len) < 0)
+ goto fail;
+ if ((bin1[prime_len - 1] & 0x03) != 3) {
+ wpa_printf(MSG_DEBUG, "SSWU: prime does not have p = 3 mod 4");
+ goto fail;
+ }
+ y = crypto_bignum_init();
+ if (!y ||
+ crypto_bignum_add(prime, one, t1) < 0 ||
+ crypto_bignum_rshift(t1, 2, t1) < 0 ||
+ crypto_bignum_exptmod(v, t1, prime, y) < 0)
+ goto fail;
+ debug_print_bignum("SSWU: y = sqrt(v)", y, prime_len);
- os_memset(null_key, 0, sizeof(null_key));
- hmac_sha256(null_key, sizeof(null_key), k, 32, keyseed);
- wpa_hexdump_key(MSG_DEBUG, "SAE: keyseed", keyseed, sizeof(keyseed));
-
- BN_add(tmp, own_scalar, peer_scalar);
- BN_mod(tmp, tmp, order, bnctx);
- sae_bn_to_bin(tmp, val, sizeof(group19_prime));
- wpa_hexdump(MSG_DEBUG, "SAE: PMKID", val, 16);
- sha256_prf(keyseed, sizeof(keyseed), "SAE KCK and PMK",
- val, sizeof(val), keys, sizeof(keys));
- os_memcpy(sae->kck, keys, 32);
- os_memcpy(sae->pmk, keys + 32, 32);
- wpa_hexdump_key(MSG_DEBUG, "SAE: KCK", sae->kck, 32);
- wpa_hexdump_key(MSG_DEBUG, "SAE: PMK", sae->pmk, 32);
+ /* l = CEQ(LSB(u), LSB(y)) */
+ if (crypto_bignum_to_bin(u, bin1, sizeof(bin1), prime_len) < 0 ||
+ crypto_bignum_to_bin(y, bin2, sizeof(bin2), prime_len) < 0)
+ goto fail;
+ is_eq = const_time_eq(bin1[prime_len - 1] & 0x01,
+ bin2[prime_len - 1] & 0x01);
+
+ /* P = CSEL(l, (x,y), (x, p-y)) */
+ if (crypto_bignum_sub(prime, y, t1) < 0)
+ goto fail;
+ debug_print_bignum("SSWU: p - y", t1, prime_len);
+ if (crypto_bignum_to_bin(y, bin1, sizeof(bin1), prime_len) < 0 ||
+ crypto_bignum_to_bin(t1, bin2, sizeof(bin2), prime_len) < 0)
+ goto fail;
+ const_time_select_bin(is_eq, bin1, bin2, prime_len, &x_y[prime_len]);
+
+ /* output P */
+ wpa_hexdump_key(MSG_DEBUG, "SSWU: P.x", x_y, prime_len);
+ wpa_hexdump_key(MSG_DEBUG, "SSWU: P.y", &x_y[prime_len], prime_len);
+ p = crypto_ec_point_from_bin(ec, x_y);
- ret = 0;
fail:
- BN_free(order);
- BN_free(own_scalar);
- BN_free(tmp);
- return ret;
+ crypto_bignum_deinit(u2, 1);
+ crypto_bignum_deinit(t1, 1);
+ crypto_bignum_deinit(t2, 1);
+ crypto_bignum_deinit(z, 0);
+ crypto_bignum_deinit(t, 1);
+ crypto_bignum_deinit(x1a, 1);
+ crypto_bignum_deinit(x1b, 1);
+ crypto_bignum_deinit(x1, 1);
+ crypto_bignum_deinit(x2, 1);
+ crypto_bignum_deinit(gx1, 1);
+ crypto_bignum_deinit(gx2, 1);
+ crypto_bignum_deinit(y, 1);
+ crypto_bignum_deinit(v, 1);
+ crypto_bignum_deinit(zero, 0);
+ crypto_bignum_deinit(one, 0);
+ crypto_bignum_deinit(two, 0);
+ crypto_bignum_deinit(three, 0);
+ forced_memzero(bin, sizeof(bin));
+ forced_memzero(bin1, sizeof(bin1));
+ forced_memzero(bin2, sizeof(bin2));
+ forced_memzero(x_y, sizeof(x_y));
+ return p;
}
-int sae_process_commit(struct sae_data *sae)
+static int sae_pwd_seed(size_t hash_len, const u8 *ssid, size_t ssid_len,
+ const u8 *password, size_t password_len,
+ const char *identifier, u8 *pwd_seed)
{
- BN_CTX *bnctx;
- EC_GROUP *group;
- int ret = 0;
- u8 k[32];
+ const u8 *addr[2];
+ size_t len[2];
+ size_t num_elem;
- if (sae_check_peer_commit(sae) < 0)
+ /* pwd-seed = HKDF-Extract(ssid, password [ || identifier ]) */
+ addr[0] = password;
+ len[0] = password_len;
+ num_elem = 1;
+ wpa_hexdump_ascii(MSG_DEBUG, "SAE: SSID", ssid, ssid_len);
+ wpa_hexdump_ascii_key(MSG_DEBUG, "SAE: password",
+ password, password_len);
+ if (identifier) {
+ wpa_printf(MSG_DEBUG, "SAE: password identifier: %s",
+ identifier);
+ addr[num_elem] = (const u8 *) identifier;
+ len[num_elem] = os_strlen(identifier);
+ num_elem++;
+ }
+ if (hkdf_extract(hash_len, ssid, ssid_len, num_elem, addr, len,
+ pwd_seed) < 0)
return -1;
-
- bnctx = BN_CTX_new();
- group = EC_GROUP_new_by_curve_name(NID_X9_62_prime256v1);
- if (bnctx == NULL || group == NULL ||
- sae_derive_k(sae, k, bnctx, group) < 0 ||
- sae_derive_keys(sae, k, bnctx) < 0)
- ret = -1;
-
- EC_GROUP_free(group);
- BN_CTX_free(bnctx);
-
- return ret;
+ wpa_hexdump_key(MSG_DEBUG, "SAE: pwd-seed", pwd_seed, hash_len);
+ return 0;
}
-void sae_write_commit(struct sae_data *sae, struct wpabuf *buf)
+size_t sae_ecc_prime_len_2_hash_len(size_t prime_len)
{
- wpabuf_put_le16(buf, 19); /* Finite Cyclic Group */
- /* TODO: Anti-Clogging Token (if requested) */
- wpabuf_put_data(buf, sae->own_commit_scalar, 32);
- wpabuf_put_data(buf, sae->own_commit_element, 2 * 32);
+ if (prime_len <= 256 / 8)
+ return 32;
+ if (prime_len <= 384 / 8)
+ return 48;
+ return 64;
}
-u16 sae_parse_commit(struct sae_data *sae, const u8 *data, size_t len)
+static struct crypto_ec_point *
+sae_derive_pt_ecc(struct crypto_ec *ec, int group,
+ const u8 *ssid, size_t ssid_len,
+ const u8 *password, size_t password_len,
+ const char *identifier)
{
- const u8 *pos = data, *end = data + len;
- size_t val_len;
+ u8 pwd_seed[64];
+ u8 pwd_value[SAE_MAX_ECC_PRIME_LEN * 2];
+ size_t pwd_value_len, hash_len, prime_len;
+ const struct crypto_bignum *prime;
+ struct crypto_bignum *bn = NULL;
+ struct crypto_ec_point *p1 = NULL, *p2 = NULL, *pt = NULL;
+
+ prime = crypto_ec_get_prime(ec);
+ prime_len = crypto_ec_prime_len(ec);
+ if (prime_len > SAE_MAX_ECC_PRIME_LEN)
+ goto fail;
+ hash_len = sae_ecc_prime_len_2_hash_len(prime_len);
- wpa_hexdump(MSG_DEBUG, "SAE: Commit fields", data, len);
+ /* len = olen(p) + ceil(olen(p)/2) */
+ pwd_value_len = prime_len + (prime_len + 1) / 2;
- /* Check Finite Cyclic Group */
- if (pos + 2 > end)
- return WLAN_STATUS_UNSPECIFIED_FAILURE;
- if (WPA_GET_LE16(pos) != 19) {
- wpa_printf(MSG_DEBUG, "SAE: Unsupported Finite Cyclic Group %u",
- WPA_GET_LE16(pos));
- return WLAN_STATUS_FINITE_CYCLIC_GROUP_NOT_SUPPORTED;
- }
- pos += 2;
- val_len = 32;
+ if (sae_pwd_seed(hash_len, ssid, ssid_len, password, password_len,
+ identifier, pwd_seed) < 0)
+ goto fail;
- if (pos + val_len > end) {
- wpa_printf(MSG_DEBUG, "SAE: Not enough data for scalar");
- return WLAN_STATUS_UNSPECIFIED_FAILURE;
- }
- os_memcpy(sae->peer_commit_scalar, pos, val_len);
- wpa_hexdump(MSG_DEBUG, "SAE: Peer commit-scalar",
- sae->peer_commit_scalar, val_len);
- pos += val_len;
+ /* pwd-value = HKDF-Expand(pwd-seed, "SAE Hash to Element u1 P1", len)
+ */
+ if (hkdf_expand(hash_len, pwd_seed, hash_len,
+ "SAE Hash to Element u1 P1", pwd_value, pwd_value_len) <
+ 0)
+ goto fail;
+ wpa_hexdump_key(MSG_DEBUG, "SAE: pwd-value (u1 P1)",
+ pwd_value, pwd_value_len);
+
+ /* u1 = pwd-value modulo p */
+ bn = crypto_bignum_init_set(pwd_value, pwd_value_len);
+ if (!bn || crypto_bignum_mod(bn, prime, bn) < 0 ||
+ crypto_bignum_to_bin(bn, pwd_value, sizeof(pwd_value),
+ prime_len) < 0)
+ goto fail;
+ wpa_hexdump_key(MSG_DEBUG, "SAE: u1", pwd_value, prime_len);
- if (pos + 2 * val_len > end) {
- wpa_printf(MSG_DEBUG, "SAE: Not enough data for "
- "commit-element");
- return WLAN_STATUS_UNSPECIFIED_FAILURE;
- }
- os_memcpy(sae->peer_commit_element, pos, 2 * val_len);
- wpa_hexdump(MSG_DEBUG, "SAE: Peer commit-element(x)",
- sae->peer_commit_element, val_len);
- wpa_hexdump(MSG_DEBUG, "SAE: Peer commit-element(y)",
- sae->peer_commit_element + val_len, val_len);
- pos += 2 * val_len;
+ /* P1 = SSWU(u1) */
+ p1 = sswu(ec, group, bn);
+ if (!p1)
+ goto fail;
+
+ /* pwd-value = HKDF-Expand(pwd-seed, "SAE Hash to Element u2 P2", len)
+ */
+ if (hkdf_expand(hash_len, pwd_seed, hash_len,
+ "SAE Hash to Element u2 P2", pwd_value,
+ pwd_value_len) < 0)
+ goto fail;
+ wpa_hexdump_key(MSG_DEBUG, "SAE: pwd-value (u2 P2)",
+ pwd_value, pwd_value_len);
+
+ /* u2 = pwd-value modulo p */
+ crypto_bignum_deinit(bn, 1);
+ bn = crypto_bignum_init_set(pwd_value, pwd_value_len);
+ if (!bn || crypto_bignum_mod(bn, prime, bn) < 0 ||
+ crypto_bignum_to_bin(bn, pwd_value, sizeof(pwd_value),
+ prime_len) < 0)
+ goto fail;
+ wpa_hexdump_key(MSG_DEBUG, "SAE: u2", pwd_value, prime_len);
+
+ /* P2 = SSWU(u2) */
+ p2 = sswu(ec, group, bn);
+ if (!p2)
+ goto fail;
- if (end > pos) {
- wpa_hexdump(MSG_DEBUG, "SAE: Unexpected extra data in commit",
- pos, end - pos);
+ /* PT = elem-op(P1, P2) */
+ pt = crypto_ec_point_init(ec);
+ if (!pt)
+ goto fail;
+ if (crypto_ec_point_add(ec, p1, p2, pt) < 0) {
+ crypto_ec_point_deinit(pt, 1);
+ pt = NULL;
}
- return WLAN_STATUS_SUCCESS;
+fail:
+ forced_memzero(pwd_seed, sizeof(pwd_seed));
+ forced_memzero(pwd_value, sizeof(pwd_value));
+ crypto_bignum_deinit(bn, 1);
+ crypto_ec_point_deinit(p1, 1);
+ crypto_ec_point_deinit(p2, 1);
+ return pt;
}
-void sae_write_confirm(struct sae_data *sae, struct wpabuf *buf)
+size_t sae_ffc_prime_len_2_hash_len(size_t prime_len)
{
- const u8 *sc;
- const u8 *addr[5];
- size_t len[5];
-
- /* Send-Confirm */
- sc = wpabuf_put(buf, 0);
- wpabuf_put_le16(buf, sae->send_confirm);
- sae->send_confirm++;
-
- /* 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)
- */
- addr[0] = sc;
- len[0] = 2;
- addr[1] = sae->own_commit_scalar;
- len[1] = 32;
- addr[2] = sae->own_commit_element;
- len[2] = 2 * 32;
- addr[3] = sae->peer_commit_scalar;
- len[3] = 32;
- addr[4] = sae->peer_commit_element;
- len[4] = 2 * 32;
- hmac_sha256_vector(sae->kck, sizeof(sae->kck), 5, addr, len,
- wpabuf_put(buf, SHA256_MAC_LEN));
+ if (prime_len <= 2048 / 8)
+ return 32;
+ if (prime_len <= 3072 / 8)
+ return 48;
+ return 64;
}
-int sae_check_confirm(struct sae_data *sae, const u8 *data, size_t len)
+static struct crypto_bignum *
+sae_derive_pt_ffc(const struct dh_group *dh, int group,
+ const u8 *ssid, size_t ssid_len,
+ const u8 *password, size_t password_len,
+ const char *identifier)
{
- u16 rc;
- const u8 *addr[5];
- size_t elen[5];
- u8 verifier[SHA256_MAC_LEN];
+ size_t hash_len, prime_len, pwd_value_len;
+ struct crypto_bignum *prime, *order;
+ struct crypto_bignum *one = NULL, *two = NULL, *bn = NULL, *tmp = NULL,
+ *pt = NULL;
+ u8 pwd_seed[64];
+ u8 pwd_value[SAE_MAX_PRIME_LEN + SAE_MAX_PRIME_LEN / 2];
+
+ prime = crypto_bignum_init_set(dh->prime, dh->prime_len);
+ order = crypto_bignum_init_set(dh->order, dh->order_len);
+ if (!prime || !order)
+ goto fail;
+ prime_len = dh->prime_len;
+ if (prime_len > SAE_MAX_PRIME_LEN)
+ goto fail;
+ hash_len = sae_ffc_prime_len_2_hash_len(prime_len);
- wpa_hexdump(MSG_DEBUG, "SAE: Confirm fields", data, len);
+ /* len = olen(p) + ceil(olen(p)/2) */
+ pwd_value_len = prime_len + (prime_len + 1) / 2;
+ if (pwd_value_len > sizeof(pwd_value))
+ goto fail;
- if (len < 2 + SHA256_MAC_LEN) {
- wpa_printf(MSG_DEBUG, "SAE: Too short confirm message");
+ if (sae_pwd_seed(hash_len, ssid, ssid_len, password, password_len,
+ identifier, pwd_seed) < 0)
+ goto fail;
+
+ /* pwd-value = HKDF-Expand(pwd-seed, "SAE Hash to Element", len) */
+ if (hkdf_expand(hash_len, pwd_seed, hash_len,
+ "SAE Hash to Element", pwd_value, pwd_value_len) < 0)
+ goto fail;
+ wpa_hexdump_key(MSG_DEBUG, "SAE: pwd-value",
+ pwd_value, pwd_value_len);
+
+ /* pwd-value = (pwd-value modulo (p-2)) + 2 */
+ bn = crypto_bignum_init_set(pwd_value, pwd_value_len);
+ one = crypto_bignum_init_uint(1);
+ two = crypto_bignum_init_uint(2);
+ tmp = crypto_bignum_init();
+ if (!bn || !one || !two || !tmp ||
+ crypto_bignum_sub(prime, two, tmp) < 0 ||
+ crypto_bignum_mod(bn, tmp, bn) < 0 ||
+ crypto_bignum_add(bn, two, bn) < 0 ||
+ crypto_bignum_to_bin(bn, pwd_value, sizeof(pwd_value),
+ prime_len) < 0)
+ goto fail;
+ wpa_hexdump_key(MSG_DEBUG, "SAE: pwd-value(reduced)",
+ pwd_value, prime_len);
+
+ /* PT = pwd-value^((p-1)/q) modulo p */
+ pt = crypto_bignum_init();
+ if (!pt ||
+ crypto_bignum_sub(prime, one, tmp) < 0 ||
+ crypto_bignum_div(tmp, order, tmp) < 0 ||
+ crypto_bignum_exptmod(bn, tmp, prime, pt) < 0) {
+ crypto_bignum_deinit(pt, 1);
+ pt = NULL;
+ goto fail;
+ }
+ debug_print_bignum("SAE: PT", pt, prime_len);
+
+fail:
+ forced_memzero(pwd_seed, sizeof(pwd_seed));
+ forced_memzero(pwd_value, sizeof(pwd_value));
+ crypto_bignum_deinit(bn, 1);
+ crypto_bignum_deinit(tmp, 1);
+ crypto_bignum_deinit(one, 0);
+ crypto_bignum_deinit(two, 0);
+ crypto_bignum_deinit(prime, 0);
+ crypto_bignum_deinit(order, 0);
+ return pt;
+}
+
+
+static struct sae_pt *
+sae_derive_pt_group(int group, const u8 *ssid, size_t ssid_len,
+ const u8 *password, size_t password_len,
+ const char *identifier)
+{
+ struct sae_pt *pt;
+
+ wpa_printf(MSG_DEBUG, "SAE: Derive PT - group %d", group);
+
+ pt = os_zalloc(sizeof(*pt));
+ if (!pt)
+ return NULL;
+
+ pt->group = group;
+ pt->ec = crypto_ec_init(group);
+ if (pt->ec) {
+ pt->ecc_pt = sae_derive_pt_ecc(pt->ec, group, ssid, ssid_len,
+ password, password_len,
+ identifier);
+ if (!pt->ecc_pt) {
+ wpa_printf(MSG_DEBUG, "SAE: Failed to derive PT");
+ goto fail;
+ }
+
+ return pt;
+ }
+
+ pt->dh = dh_groups_get(group);
+ if (!pt->dh) {
+ wpa_printf(MSG_DEBUG, "SAE: Unsupported group %d", group);
+ goto fail;
+ }
+
+ pt->ffc_pt = sae_derive_pt_ffc(pt->dh, group, ssid, ssid_len,
+ password, password_len, identifier);
+ if (!pt->ffc_pt) {
+ wpa_printf(MSG_DEBUG, "SAE: Failed to derive PT");
+ goto fail;
+ }
+
+ return pt;
+fail:
+ sae_deinit_pt(pt);
+ return NULL;
+}
+
+
+struct sae_pt * sae_derive_pt(int *groups, const u8 *ssid, size_t ssid_len,
+ const u8 *password, size_t password_len,
+ const char *identifier)
+{
+ struct sae_pt *pt = NULL, *last = NULL, *tmp;
+ int default_groups[] = { 19, 0 };
+ int i;
+
+ if (!groups)
+ groups = default_groups;
+ for (i = 0; groups[i] > 0; i++) {
+ tmp = sae_derive_pt_group(groups[i], ssid, ssid_len, password,
+ password_len, identifier);
+ if (!tmp)
+ continue;
+
+ if (last)
+ last->next = tmp;
+ else
+ pt = tmp;
+ last = tmp;
+ }
+
+ return pt;
+}
+
+
+static void sae_max_min_addr(const u8 *addr[], size_t len[],
+ const u8 *addr1, const u8 *addr2)
+{
+ len[0] = ETH_ALEN;
+ len[1] = ETH_ALEN;
+ if (os_memcmp(addr1, addr2, ETH_ALEN) > 0) {
+ addr[0] = addr1;
+ addr[1] = addr2;
+ } else {
+ addr[0] = addr2;
+ addr[1] = addr1;
+ }
+}
+
+
+struct crypto_ec_point *
+sae_derive_pwe_from_pt_ecc(const struct sae_pt *pt,
+ const u8 *addr1, const u8 *addr2)
+{
+ u8 bin[SAE_MAX_ECC_PRIME_LEN * 2];
+ size_t prime_len;
+ const u8 *addr[2];
+ size_t len[2];
+ u8 salt[64], hash[64];
+ size_t hash_len;
+ const struct crypto_bignum *order;
+ struct crypto_bignum *tmp = NULL, *val = NULL, *one = NULL;
+ struct crypto_ec_point *pwe = NULL;
+
+ wpa_printf(MSG_DEBUG, "SAE: Derive PWE from PT");
+ prime_len = crypto_ec_prime_len(pt->ec);
+ if (crypto_ec_point_to_bin(pt->ec, pt->ecc_pt,
+ bin, bin + prime_len) < 0)
+ return NULL;
+ wpa_hexdump_key(MSG_DEBUG, "SAE: PT.x", bin, prime_len);
+ wpa_hexdump_key(MSG_DEBUG, "SAE: PT.y", bin + prime_len, prime_len);
+
+ sae_max_min_addr(addr, len, addr1, addr2);
+
+ /* val = H(0^n,
+ * MAX(STA-A-MAC, STA-B-MAC) || MIN(STA-A-MAC, STA-B-MAC)) */
+ wpa_printf(MSG_DEBUG, "SAE: val = H(0^n, MAX(addrs) || MIN(addrs))");
+ hash_len = sae_ecc_prime_len_2_hash_len(prime_len);
+ os_memset(salt, 0, hash_len);
+ if (hkdf_extract(hash_len, salt, hash_len, 2, addr, len, hash) < 0)
+ goto fail;
+ wpa_hexdump(MSG_DEBUG, "SAE: val", hash, hash_len);
+
+ /* val = val modulo (q - 1) + 1 */
+ order = crypto_ec_get_order(pt->ec);
+ tmp = crypto_bignum_init();
+ val = crypto_bignum_init_set(hash, hash_len);
+ one = crypto_bignum_init_uint(1);
+ if (!tmp || !val || !one ||
+ crypto_bignum_sub(order, one, tmp) < 0 ||
+ crypto_bignum_mod(val, tmp, val) < 0 ||
+ crypto_bignum_add(val, one, val) < 0)
+ goto fail;
+ debug_print_bignum("SAE: val(reduced to 1..q-1)", val, prime_len);
+
+ /* PWE = scalar-op(val, PT) */
+ pwe = crypto_ec_point_init(pt->ec);
+ if (!pwe ||
+ crypto_ec_point_mul(pt->ec, pt->ecc_pt, val, pwe) < 0 ||
+ crypto_ec_point_to_bin(pt->ec, pwe, bin, bin + prime_len) < 0) {
+ crypto_ec_point_deinit(pwe, 1);
+ pwe = NULL;
+ goto fail;
+ }
+ wpa_hexdump_key(MSG_DEBUG, "SAE: PWE.x", bin, prime_len);
+ wpa_hexdump_key(MSG_DEBUG, "SAE: PWE.y", bin + prime_len, prime_len);
+
+fail:
+ crypto_bignum_deinit(tmp, 1);
+ crypto_bignum_deinit(val, 1);
+ crypto_bignum_deinit(one, 0);
+ return pwe;
+}
+
+
+struct crypto_bignum *
+sae_derive_pwe_from_pt_ffc(const struct sae_pt *pt,
+ const u8 *addr1, const u8 *addr2)
+{
+ size_t prime_len;
+ const u8 *addr[2];
+ size_t len[2];
+ u8 salt[64], hash[64];
+ size_t hash_len;
+ struct crypto_bignum *tmp = NULL, *val = NULL, *one = NULL;
+ struct crypto_bignum *pwe = NULL, *order = NULL, *prime = NULL;
+
+ wpa_printf(MSG_DEBUG, "SAE: Derive PWE from PT");
+ prime = crypto_bignum_init_set(pt->dh->prime, pt->dh->prime_len);
+ order = crypto_bignum_init_set(pt->dh->order, pt->dh->order_len);
+ if (!prime || !order)
+ goto fail;
+ prime_len = pt->dh->prime_len;
+
+ sae_max_min_addr(addr, len, addr1, addr2);
+
+ /* val = H(0^n,
+ * MAX(STA-A-MAC, STA-B-MAC) || MIN(STA-A-MAC, STA-B-MAC)) */
+ wpa_printf(MSG_DEBUG, "SAE: val = H(0^n, MAX(addrs) || MIN(addrs))");
+ hash_len = sae_ffc_prime_len_2_hash_len(prime_len);
+ os_memset(salt, 0, hash_len);
+ if (hkdf_extract(hash_len, salt, hash_len, 2, addr, len, hash) < 0)
+ goto fail;
+ wpa_hexdump(MSG_DEBUG, "SAE: val", hash, hash_len);
+
+ /* val = val modulo (q - 1) + 1 */
+ tmp = crypto_bignum_init();
+ val = crypto_bignum_init_set(hash, hash_len);
+ one = crypto_bignum_init_uint(1);
+ if (!tmp || !val || !one ||
+ crypto_bignum_sub(order, one, tmp) < 0 ||
+ crypto_bignum_mod(val, tmp, val) < 0 ||
+ crypto_bignum_add(val, one, val) < 0)
+ goto fail;
+ debug_print_bignum("SAE: val(reduced to 1..q-1)", val, prime_len);
+
+ /* PWE = scalar-op(val, PT) */
+ pwe = crypto_bignum_init();
+ if (!pwe || crypto_bignum_exptmod(pt->ffc_pt, val, prime, pwe) < 0) {
+ crypto_bignum_deinit(pwe, 1);
+ pwe = NULL;
+ goto fail;
+ }
+ debug_print_bignum("SAE: PWE", pwe, prime_len);
+
+fail:
+ crypto_bignum_deinit(tmp, 1);
+ crypto_bignum_deinit(val, 1);
+ crypto_bignum_deinit(one, 0);
+ crypto_bignum_deinit(prime, 0);
+ crypto_bignum_deinit(order, 0);
+ return pwe;
+}
+
+
+void sae_deinit_pt(struct sae_pt *pt)
+{
+ struct sae_pt *prev;
+
+ while (pt) {
+ crypto_ec_point_deinit(pt->ecc_pt, 1);
+ crypto_bignum_deinit(pt->ffc_pt, 1);
+ crypto_ec_deinit(pt->ec);
+ prev = pt;
+ pt = pt->next;
+ os_free(prev);
+ }
+}
+
+
+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;
}
- rc = WPA_GET_LE16(data);
- wpa_printf(MSG_DEBUG, "SAE: peer-send-confirm %u", rc);
+ return 0;
+}
+
+
+static int sae_derive_commit(struct sae_data *sae)
+{
+ struct crypto_bignum *mask;
+ int ret;
+
+ mask = crypto_bignum_init();
+ if (!sae->tmp->sae_rand)
+ sae->tmp->sae_rand = crypto_bignum_init();
+ if (!sae->tmp->own_commit_scalar)
+ sae->tmp->own_commit_scalar = crypto_bignum_init();
+ ret = !mask || !sae->tmp->sae_rand || !sae->tmp->own_commit_scalar ||
+ dragonfly_generate_scalar(sae->tmp->order, sae->tmp->sae_rand,
+ mask,
+ sae->tmp->own_commit_scalar) < 0 ||
+ (sae->tmp->ec &&
+ sae_derive_commit_element_ecc(sae, mask) < 0) ||
+ (sae->tmp->dh &&
+ sae_derive_commit_element_ffc(sae, mask) < 0);
+ crypto_bignum_deinit(mask, 1);
+ return ret ? -1 : 0;
+}
+
+
+int sae_prepare_commit(const u8 *addr1, const u8 *addr2,
+ const u8 *password, size_t password_len,
+ const char *identifier, struct sae_data *sae)
+{
+ if (sae->tmp == NULL ||
+ (sae->tmp->ec && sae_derive_pwe_ecc(sae, addr1, addr2, password,
+ password_len,
+ identifier) < 0) ||
+ (sae->tmp->dh && sae_derive_pwe_ffc(sae, addr1, addr2, password,
+ password_len,
+ identifier) < 0))
+ return -1;
+
+ sae->tmp->h2e = 0;
+ return sae_derive_commit(sae);
+}
+
+
+int sae_prepare_commit_pt(struct sae_data *sae, const struct sae_pt *pt,
+ const u8 *addr1, const u8 *addr2,
+ int *rejected_groups)
+{
+ if (!sae->tmp)
+ return -1;
+
+ while (pt) {
+ if (pt->group == sae->group)
+ break;
+ pt = pt->next;
+ }
+ if (!pt) {
+ wpa_printf(MSG_INFO, "SAE: Could not find PT for group %u",
+ sae->group);
+ return -1;
+ }
+
+ sae->tmp->own_addr_higher = os_memcmp(addr1, addr2, ETH_ALEN) > 0;
+ wpabuf_free(sae->tmp->own_rejected_groups);
+ sae->tmp->own_rejected_groups = NULL;
+ if (rejected_groups) {
+ int count, i;
+ struct wpabuf *groups;
+
+ count = int_array_len(rejected_groups);
+ groups = wpabuf_alloc(count * 2);
+ if (!groups)
+ return -1;
+ for (i = 0; i < count; i++)
+ wpabuf_put_le16(groups, rejected_groups[i]);
+ sae->tmp->own_rejected_groups = groups;
+ }
+
+ if (pt->ec) {
+ crypto_ec_point_deinit(sae->tmp->pwe_ecc, 1);
+ sae->tmp->pwe_ecc = sae_derive_pwe_from_pt_ecc(pt, addr1,
+ addr2);
+ if (!sae->tmp->pwe_ecc)
+ return -1;
+ }
+
+ if (pt->dh) {
+ crypto_bignum_deinit(sae->tmp->pwe_ffc, 1);
+ sae->tmp->pwe_ffc = sae_derive_pwe_from_pt_ffc(pt, addr1,
+ addr2);
+ if (!sae->tmp->pwe_ffc)
+ return -1;
+ }
+
+ sae->tmp->h2e = 1;
+ return sae_derive_commit(sae);
+}
+
+
+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_kdf_hash(size_t hash_len, const u8 *k, const char *label,
+ const u8 *context, size_t context_len,
+ u8 *out, size_t out_len)
+{
+ if (hash_len == 32)
+ return sha256_prf(k, hash_len, label,
+ context, context_len, out, out_len);
+#ifdef CONFIG_SHA384
+ if (hash_len == 48)
+ return sha384_prf(k, hash_len, label,
+ context, context_len, out, out_len);
+#endif /* CONFIG_SHA384 */
+#ifdef CONFIG_SHA512
+ if (hash_len == 64)
+ return sha512_prf(k, hash_len, label,
+ context, context_len, out, out_len);
+#endif /* CONFIG_SHA512 */
+ return -1;
+}
+
+
+static int sae_derive_keys(struct sae_data *sae, const u8 *k)
+{
+ u8 zero[SAE_MAX_HASH_LEN], val[SAE_MAX_PRIME_LEN];
+ const u8 *salt;
+ struct wpabuf *rejected_groups = NULL;
+ u8 keyseed[SAE_MAX_HASH_LEN];
+ u8 keys[SAE_MAX_HASH_LEN + SAE_PMK_LEN];
+ struct crypto_bignum *tmp;
+ int ret = -1;
+ size_t hash_len, salt_len, prime_len = sae->tmp->prime_len;
+ const u8 *addr[1];
+ size_t len[1];
+
+ tmp = crypto_bignum_init();
+ if (tmp == NULL)
+ goto fail;
+
+ /* keyseed = H(salt, k)
+ * KCK || PMK = KDF-Hash-Length(keyseed, "SAE KCK and PMK",
+ * (commit-scalar + peer-commit-scalar) modulo r)
+ * PMKID = L((commit-scalar + peer-commit-scalar) modulo r, 0, 128)
+ */
+ if (!sae->tmp->h2e)
+ hash_len = SHA256_MAC_LEN;
+ else if (sae->tmp->dh)
+ hash_len = sae_ffc_prime_len_2_hash_len(prime_len);
+ else
+ hash_len = sae_ecc_prime_len_2_hash_len(prime_len);
+ if (sae->tmp->h2e && (sae->tmp->own_rejected_groups ||
+ sae->tmp->peer_rejected_groups)) {
+ struct wpabuf *own, *peer;
+
+ own = sae->tmp->own_rejected_groups;
+ peer = sae->tmp->peer_rejected_groups;
+ salt_len = 0;
+ if (own)
+ salt_len += wpabuf_len(own);
+ if (peer)
+ salt_len += wpabuf_len(peer);
+ rejected_groups = wpabuf_alloc(salt_len);
+ if (!rejected_groups)
+ goto fail;
+ if (sae->tmp->own_addr_higher) {
+ if (own)
+ wpabuf_put_buf(rejected_groups, own);
+ if (peer)
+ wpabuf_put_buf(rejected_groups, peer);
+ } else {
+ if (peer)
+ wpabuf_put_buf(rejected_groups, peer);
+ if (own)
+ wpabuf_put_buf(rejected_groups, own);
+ }
+ salt = wpabuf_head(rejected_groups);
+ salt_len = wpabuf_len(rejected_groups);
+ } else {
+ os_memset(zero, 0, hash_len);
+ salt = zero;
+ salt_len = hash_len;
+ }
+ wpa_hexdump(MSG_DEBUG, "SAE: salt for keyseed derivation",
+ salt, salt_len);
+ addr[0] = k;
+ len[0] = prime_len;
+ if (hkdf_extract(hash_len, salt, salt_len, 1, addr, len, keyseed) < 0)
+ goto fail;
+ wpa_hexdump_key(MSG_DEBUG, "SAE: keyseed", keyseed, hash_len);
+
+ if (crypto_bignum_add(sae->tmp->own_commit_scalar,
+ sae->peer_commit_scalar, tmp) < 0 ||
+ crypto_bignum_mod(tmp, sae->tmp->order, tmp) < 0)
+ goto fail;
+ /* IEEE Std 802.11-2016 is not exactly clear on the encoding of the bit
+ * string that is needed for KCK, PMK, and PMKID derivation, but it
+ * seems to make most sense to encode the
+ * (commit-scalar + peer-commit-scalar) mod r part as a bit string by
+ * zero padding it from left to the length of the order (in full
+ * octets). */
+ crypto_bignum_to_bin(tmp, val, sizeof(val), sae->tmp->order_len);
+ wpa_hexdump(MSG_DEBUG, "SAE: PMKID", val, SAE_PMKID_LEN);
+ if (sae_kdf_hash(hash_len, keyseed, "SAE KCK and PMK",
+ val, sae->tmp->order_len,
+ keys, hash_len + SAE_PMK_LEN) < 0)
+ goto fail;
+ forced_memzero(keyseed, sizeof(keyseed));
+ os_memcpy(sae->tmp->kck, keys, hash_len);
+ sae->tmp->kck_len = hash_len;
+ os_memcpy(sae->pmk, keys + hash_len, SAE_PMK_LEN);
+ os_memcpy(sae->pmkid, val, SAE_PMKID_LEN);
+ forced_memzero(keys, sizeof(keys));
+ wpa_hexdump_key(MSG_DEBUG, "SAE: KCK",
+ sae->tmp->kck, sae->tmp->kck_len);
+ wpa_hexdump_key(MSG_DEBUG, "SAE: PMK", sae->pmk, SAE_PMK_LEN);
+
+ ret = 0;
+fail:
+ wpabuf_free(rejected_groups);
+ 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, const char *identifier)
+{
+ u8 *pos;
+
+ if (sae->tmp == NULL)
+ return;
+
+ wpabuf_put_le16(buf, sae->group); /* Finite Cyclic Group */
+ if (!sae->tmp->h2e && 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);
+ }
+
+ if (identifier) {
+ /* Password Identifier element */
+ wpabuf_put_u8(buf, WLAN_EID_EXTENSION);
+ wpabuf_put_u8(buf, 1 + os_strlen(identifier));
+ wpabuf_put_u8(buf, WLAN_EID_EXT_PASSWORD_IDENTIFIER);
+ wpabuf_put_str(buf, identifier);
+ wpa_printf(MSG_DEBUG, "SAE: own Password Identifier: %s",
+ identifier);
+ }
+
+ if (sae->tmp->h2e && sae->tmp->own_rejected_groups) {
+ wpa_hexdump_buf(MSG_DEBUG, "SAE: own Rejected Groups",
+ sae->tmp->own_rejected_groups);
+ wpabuf_put_u8(buf, WLAN_EID_EXTENSION);
+ wpabuf_put_u8(buf,
+ 1 + wpabuf_len(sae->tmp->own_rejected_groups));
+ wpabuf_put_u8(buf, WLAN_EID_EXT_REJECTED_GROUPS);
+ wpabuf_put_buf(buf, sae->tmp->own_rejected_groups);
+ }
+
+ if (sae->tmp->h2e && token) {
+ wpabuf_put_u8(buf, WLAN_EID_EXTENSION);
+ wpabuf_put_u8(buf, 1 + wpabuf_len(token));
+ wpabuf_put_u8(buf, WLAN_EID_EXT_ANTI_CLOGGING_TOKEN);
+ wpabuf_put_buf(buf, token);
+ wpa_hexdump_buf(MSG_DEBUG,
+ "SAE: Anti-clogging token (in container)",
+ token);
+ }
+}
+
+
+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 int sae_is_password_id_elem(const u8 *pos, const u8 *end)
+{
+ return end - pos >= 3 &&
+ pos[0] == WLAN_EID_EXTENSION &&
+ pos[1] >= 1 &&
+ end - pos - 2 >= pos[1] &&
+ pos[2] == WLAN_EID_EXT_PASSWORD_IDENTIFIER;
+}
+
+
+static int sae_is_rejected_groups_elem(const u8 *pos, const u8 *end)
+{
+ return end - pos >= 3 &&
+ pos[0] == WLAN_EID_EXTENSION &&
+ pos[1] >= 2 &&
+ end - pos - 2 >= pos[1] &&
+ pos[2] == WLAN_EID_EXT_REJECTED_GROUPS;
+}
+
+
+static int sae_is_token_container_elem(const u8 *pos, const u8 *end)
+{
+ return end - pos >= 3 &&
+ pos[0] == WLAN_EID_EXTENSION &&
+ pos[1] >= 1 &&
+ end - pos - 2 >= pos[1] &&
+ pos[2] == WLAN_EID_EXT_ANTI_CLOGGING_TOKEN;
+}
+
+
+static void sae_parse_commit_token(struct sae_data *sae, const u8 **pos,
+ const u8 *end, const u8 **token,
+ size_t *token_len, int h2e)
+{
+ size_t scalar_elem_len, tlen;
+
+ if (token)
+ *token = NULL;
+ if (token_len)
+ *token_len = 0;
+
+ if (h2e)
+ return; /* No Anti-Clogging Token field outside container IE */
+
+ scalar_elem_len = (sae->tmp->ec ? 3 : 2) * sae->tmp->prime_len;
+ if (scalar_elem_len >= (size_t) (end - *pos))
+ return; /* No extra data beyond peer scalar and element */
+
+ tlen = end - (*pos + scalar_elem_len);
+
+ if (tlen < SHA256_MAC_LEN) {
+ wpa_printf(MSG_DEBUG,
+ "SAE: Too short optional data (%u octets) to include our Anti-Clogging Token",
+ (unsigned int) tlen);
+ return;
+ }
+
+ wpa_hexdump(MSG_DEBUG, "SAE: Anti-Clogging Token", *pos, tlen);
+ if (token)
+ *token = *pos;
+ if (token_len)
+ *token_len = tlen;
+ *pos += tlen;
+}
+
+
+static void sae_parse_token_container(struct sae_data *sae,
+ const u8 *pos, const u8 *end,
+ const u8 **token, size_t *token_len)
+{
+ wpa_hexdump(MSG_DEBUG, "SAE: Possible elements at the end of the frame",
+ pos, end - pos);
+ if (!sae_is_token_container_elem(pos, end))
+ return;
+ *token = pos + 3;
+ *token_len = pos[1] - 1;
+ wpa_hexdump(MSG_DEBUG, "SAE: Anti-Clogging Token (in container)",
+ *token, *token_len);
+}
+
+
+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_accepted &&
+ crypto_bignum_cmp(sae->peer_commit_scalar_accepted,
+ 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;
+ }
+
+ *pos += 2 * sae->tmp->prime_len;
+
+ 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);
+
+ *pos += sae->tmp->prime_len;
+
+ 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);
+}
+
+
+static int sae_parse_password_identifier(struct sae_data *sae,
+ const u8 **pos, const u8 *end)
+{
+ wpa_hexdump(MSG_DEBUG, "SAE: Possible elements at the end of the frame",
+ *pos, end - *pos);
+ if (!sae_is_password_id_elem(*pos, end)) {
+ if (sae->tmp->pw_id) {
+ wpa_printf(MSG_DEBUG,
+ "SAE: No Password Identifier included, but expected one (%s)",
+ sae->tmp->pw_id);
+ return WLAN_STATUS_UNKNOWN_PASSWORD_IDENTIFIER;
+ }
+ os_free(sae->tmp->pw_id);
+ sae->tmp->pw_id = NULL;
+ return WLAN_STATUS_SUCCESS; /* No Password Identifier */
+ }
+
+ if (sae->tmp->pw_id &&
+ ((*pos)[1] - 1 != (int) os_strlen(sae->tmp->pw_id) ||
+ os_memcmp(sae->tmp->pw_id, (*pos) + 3, (*pos)[1] - 1) != 0)) {
+ wpa_printf(MSG_DEBUG,
+ "SAE: The included Password Identifier does not match the expected one (%s)",
+ sae->tmp->pw_id);
+ return WLAN_STATUS_UNKNOWN_PASSWORD_IDENTIFIER;
+ }
+
+ os_free(sae->tmp->pw_id);
+ sae->tmp->pw_id = os_malloc((*pos)[1]);
+ if (!sae->tmp->pw_id)
+ return WLAN_STATUS_UNSPECIFIED_FAILURE;
+ os_memcpy(sae->tmp->pw_id, (*pos) + 3, (*pos)[1] - 1);
+ sae->tmp->pw_id[(*pos)[1] - 1] = '\0';
+ wpa_hexdump_ascii(MSG_DEBUG, "SAE: Received Password Identifier",
+ sae->tmp->pw_id, (*pos)[1] - 1);
+ *pos = *pos + 2 + (*pos)[1];
+ return WLAN_STATUS_SUCCESS;
+}
+
+
+static int sae_parse_rejected_groups(struct sae_data *sae,
+ const u8 **pos, const u8 *end)
+{
+ wpa_hexdump(MSG_DEBUG, "SAE: Possible elements at the end of the frame",
+ *pos, end - *pos);
+ if (!sae_is_rejected_groups_elem(*pos, end))
+ return WLAN_STATUS_SUCCESS;
+ wpabuf_free(sae->tmp->peer_rejected_groups);
+ sae->tmp->peer_rejected_groups = wpabuf_alloc((*pos)[1] - 1);
+ if (!sae->tmp->peer_rejected_groups)
+ return WLAN_STATUS_UNSPECIFIED_FAILURE;
+ wpabuf_put_data(sae->tmp->peer_rejected_groups, (*pos) + 3,
+ (*pos)[1] - 1);
+ wpa_hexdump_buf(MSG_DEBUG, "SAE: Received Rejected Groups list",
+ sae->tmp->peer_rejected_groups);
+ *pos = *pos + 2 + (*pos)[1];
+ return WLAN_STATUS_SUCCESS;
+}
+
+
+u16 sae_parse_commit(struct sae_data *sae, const u8 *data, size_t len,
+ const u8 **token, size_t *token_len, int *allowed_groups,
+ int h2e)
+{
+ 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, h2e);
+
+ /* 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;
+
+ /* Optional Password Identifier element */
+ res = sae_parse_password_identifier(sae, &pos, end);
+ if (res != WLAN_STATUS_SUCCESS)
+ return res;
+
+ /* Conditional Rejected Groups element */
+ if (h2e) {
+ res = sae_parse_rejected_groups(sae, &pos, end);
+ if (res != WLAN_STATUS_SUCCESS)
+ return res;
+ }
+
+ /* Optional Anti-Clogging Token Container element */
+ if (h2e)
+ sae_parse_token_container(sae, pos, end, token, token_len);
+
+ /*
+ * 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 int 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] = data;
- elen[0] = 2;
- addr[1] = sae->peer_commit_scalar;
- elen[1] = 32;
- addr[2] = sae->peer_commit_element;
- elen[2] = 2 * 32;
- addr[3] = sae->own_commit_scalar;
- elen[3] = 32;
- addr[4] = sae->own_commit_element;
- elen[4] = 2 * 32;
- hmac_sha256_vector(sae->kck, sizeof(sae->kck), 5, addr, elen, verifier);
-
- if (os_memcmp(verifier, data + 2, SHA256_MAC_LEN) != 0) {
+ if (crypto_bignum_to_bin(scalar1, scalar_b1, sizeof(scalar_b1),
+ sae->tmp->prime_len) < 0 ||
+ crypto_bignum_to_bin(scalar2, scalar_b2, sizeof(scalar_b2),
+ sae->tmp->prime_len) < 0)
+ return -1;
+ addr[0] = sc;
+ len[0] = 2;
+ addr[1] = scalar_b1;
+ len[1] = sae->tmp->prime_len;
+ addr[2] = element1;
+ len[2] = element1_len;
+ addr[3] = scalar_b2;
+ len[3] = sae->tmp->prime_len;
+ addr[4] = element2;
+ len[4] = element2_len;
+ return hkdf_extract(sae->tmp->kck_len, sae->tmp->kck, sae->tmp->kck_len,
+ 5, addr, len, confirm);
+}
+
+
+static int 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];
+
+ if (crypto_ec_point_to_bin(sae->tmp->ec, element1, element_b1,
+ element_b1 + sae->tmp->prime_len) < 0 ||
+ crypto_ec_point_to_bin(sae->tmp->ec, element2, element_b2,
+ element_b2 + sae->tmp->prime_len) < 0 ||
+ sae_cn_confirm(sae, sc, scalar1, element_b1,
+ 2 * sae->tmp->prime_len,
+ scalar2, element_b2, 2 * sae->tmp->prime_len,
+ confirm) < 0)
+ return -1;
+ return 0;
+}
+
+
+static int 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];
+
+ if (crypto_bignum_to_bin(element1, element_b1, sizeof(element_b1),
+ sae->tmp->prime_len) < 0 ||
+ crypto_bignum_to_bin(element2, element_b2, sizeof(element_b2),
+ sae->tmp->prime_len) < 0 ||
+ sae_cn_confirm(sae, sc, scalar1, element_b1, sae->tmp->prime_len,
+ scalar2, element_b2, sae->tmp->prime_len,
+ confirm) < 0)
+ return -1;
+ return 0;
+}
+
+
+void sae_write_confirm(struct sae_data *sae, struct wpabuf *buf)
+{
+ const u8 *sc;
+ size_t hash_len;
+
+ if (sae->tmp == NULL)
+ return;
+
+ hash_len = sae->tmp->kck_len;
+
+ /* Send-Confirm */
+ sc = wpabuf_put(buf, 0);
+ wpabuf_put_le16(buf, sae->send_confirm);
+ if (sae->send_confirm < 0xffff)
+ 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, hash_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, hash_len));
+}
+
+
+int sae_check_confirm(struct sae_data *sae, const u8 *data, size_t len)
+{
+ u8 verifier[SAE_MAX_HASH_LEN];
+ size_t hash_len;
+
+ if (!sae->tmp)
+ return -1;
+
+ hash_len = sae->tmp->kck_len;
+ if (len < 2 + hash_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->peer_commit_scalar || !sae->tmp->own_commit_scalar) {
+ wpa_printf(MSG_DEBUG, "SAE: Temporary data not yet available");
+ return -1;
+ }
+
+ if (sae->tmp->ec) {
+ if (!sae->tmp->peer_commit_element_ecc ||
+ !sae->tmp->own_commit_element_ecc ||
+ 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) < 0)
+ return -1;
+ } else {
+ if (!sae->tmp->peer_commit_element_ffc ||
+ !sae->tmp->own_commit_element_ffc ||
+ 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) < 0)
+ return -1;
+ }
+
+ if (os_memcmp_const(verifier, data + 2, hash_len) != 0) {
wpa_printf(MSG_DEBUG, "SAE: Confirm mismatch");
wpa_hexdump(MSG_DEBUG, "SAE: Received confirm",
- data + 2, SHA256_MAC_LEN);
+ data + 2, hash_len);
wpa_hexdump(MSG_DEBUG, "SAE: Calculated verifier",
- verifier, SHA256_MAC_LEN);
+ verifier, hash_len);
return -1;
}
return 0;
}
+
+
+const char * sae_state_txt(enum sae_state state)
+{
+ switch (state) {
+ case SAE_NOTHING:
+ return "Nothing";
+ case SAE_COMMITTED:
+ return "Committed";
+ case SAE_CONFIRMED:
+ return "Confirmed";
+ case SAE_ACCEPTED:
+ return "Accepted";
+ }
+ return "?";
+}
projects / thirdparty / hostap.git / blobdiff