SAE: Implement hash-to-element PT/PWE crypto routines
Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
This commit is contained in:
Jouni Malinen
Jouni Malinen
parent
ecd7114072
commit
aeb022f8e5
804
src/common/sae.c
804
src/common/sae.c
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@ -12,6 +12,8 @@
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#include "utils/const_time.h"
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#include "crypto/crypto.h"
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#include "crypto/sha256.h"
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#include "crypto/sha384.h"
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#include "crypto/sha512.h"
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#include "crypto/random.h"
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#include "crypto/dh_groups.h"
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#include "ieee802_11_defs.h"
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@ -107,6 +109,7 @@ void sae_clear_temp_data(struct sae_data *sae)
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crypto_ec_point_deinit(tmp->own_commit_element_ecc, 0);
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crypto_ec_point_deinit(tmp->peer_commit_element_ecc, 0);
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wpabuf_free(tmp->anti_clogging_token);
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wpabuf_free(tmp->own_rejected_groups);
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wpabuf_free(tmp->peer_rejected_groups);
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os_free(tmp->pw_id);
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bin_clear_free(tmp, sizeof(*tmp));
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@ -526,6 +529,745 @@ fail:
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}
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static int hkdf_extract(size_t hash_len, const u8 *salt, size_t salt_len,
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size_t num_elem, const u8 *addr[], const size_t len[],
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u8 *prk)
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{
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if (hash_len == 32)
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return hmac_sha256_vector(salt, salt_len, num_elem, addr, len,
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prk);
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#ifdef CONFIG_SHA384
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if (hash_len == 48)
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return hmac_sha384_vector(salt, salt_len, num_elem, addr, len,
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prk);
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#endif /* CONFIG_SHA384 */
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#ifdef CONFIG_SHA512
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if (hash_len == 64)
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return hmac_sha512_vector(salt, salt_len, num_elem, addr, len,
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prk);
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#endif /* CONFIG_SHA512 */
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return -1;
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}
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static int hkdf_expand(size_t hash_len, const u8 *prk, size_t prk_len,
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const char *info, u8 *okm, size_t okm_len)
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{
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size_t info_len = os_strlen(info);
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if (hash_len == 32)
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return hmac_sha256_kdf(prk, prk_len, NULL,
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(const u8 *) info, info_len,
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okm, okm_len);
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#ifdef CONFIG_SHA384
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if (hash_len == 48)
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return hmac_sha384_kdf(prk, prk_len, NULL,
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(const u8 *) info, info_len,
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okm, okm_len);
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#endif /* CONFIG_SHA384 */
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#ifdef CONFIG_SHA512
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if (hash_len == 64)
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return hmac_sha512_kdf(prk, prk_len, NULL,
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(const u8 *) info, info_len,
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okm, okm_len);
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#endif /* CONFIG_SHA512 */
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return -1;
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}
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static int sswu_curve_param(int group, int *z)
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{
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switch (group) {
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case 19:
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case 20:
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case 21:
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case 28:
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*z = -2;
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return 0;
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case 25:
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case 29:
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*z = -5;
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return 0;
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case 26:
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*z = -11;
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return 0;
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case 30:
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*z = 2;
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return 0;
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}
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return -1;
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}
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static void debug_print_bignum(const char *title, const struct crypto_bignum *a,
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size_t prime_len)
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{
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u8 *bin;
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bin = os_malloc(prime_len);
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if (bin && crypto_bignum_to_bin(a, bin, prime_len, prime_len) >= 0)
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wpa_hexdump_key(MSG_DEBUG, title, bin, prime_len);
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else
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wpa_printf(MSG_DEBUG, "Could not print bignum (%s)", title);
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bin_clear_free(bin, prime_len);
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}
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static struct crypto_ec_point * sswu(struct crypto_ec *ec, int group,
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const struct crypto_bignum *u)
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{
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int z_int;
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const struct crypto_bignum *a, *b, *prime;
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struct crypto_bignum *u2, *t1, *t2, *z, *t, *zero, *one, *two, *three,
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*x1a, *x1b, *y = NULL;
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struct crypto_bignum *x1 = NULL, *x2, *gx1, *gx2, *v = NULL;
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unsigned int m_is_zero, is_qr, is_eq;
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size_t prime_len;
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u8 bin[SAE_MAX_ECC_PRIME_LEN];
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u8 bin1[SAE_MAX_ECC_PRIME_LEN];
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u8 bin2[SAE_MAX_ECC_PRIME_LEN];
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u8 x_y[2 * SAE_MAX_ECC_PRIME_LEN];
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struct crypto_ec_point *p = NULL;
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if (sswu_curve_param(group, &z_int) < 0)
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return NULL;
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prime = crypto_ec_get_prime(ec);
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prime_len = crypto_ec_prime_len(ec);
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a = crypto_ec_get_a(ec);
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b = crypto_ec_get_b(ec);
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u2 = crypto_bignum_init();
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t1 = crypto_bignum_init();
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t2 = crypto_bignum_init();
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z = crypto_bignum_init_uint(abs(z_int));
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t = crypto_bignum_init();
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zero = crypto_bignum_init_uint(0);
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one = crypto_bignum_init_uint(1);
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two = crypto_bignum_init_uint(2);
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three = crypto_bignum_init_uint(3);
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x1a = crypto_bignum_init();
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x1b = crypto_bignum_init();
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x2 = crypto_bignum_init();
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gx1 = crypto_bignum_init();
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gx2 = crypto_bignum_init();
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if (!u2 || !t1 || !t2 || !z || !t || !zero || !one || !two || !three ||
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!x1a || !x1b || !x2 || !gx1 || !gx2)
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goto fail;
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if (z_int < 0 && crypto_bignum_sub(prime, z, z) < 0)
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goto fail;
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/* m = z^2 * u^4 + z * u^2 */
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/* --> tmp = z * u^2, m = tmp^2 + tmp */
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/* u2 = u^2
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* t1 = z * u2
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* t2 = t1^2
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* m = t1 = t1 + t2 */
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if (crypto_bignum_sqrmod(u, prime, u2) < 0 ||
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crypto_bignum_mulmod(z, u2, prime, t1) < 0 ||
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crypto_bignum_sqrmod(t1, prime, t2) < 0 ||
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crypto_bignum_addmod(t1, t2, prime, t1) < 0)
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goto fail;
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debug_print_bignum("SSWU: m", t1, prime_len);
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/* l = CEQ(m, 0)
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* t = CSEL(l, 0, inverse(m); where inverse(x) is calculated as
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* x^(p-2) modulo p which will handle m == 0 case correctly */
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/* TODO: Make sure crypto_bignum_is_zero() is constant time */
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m_is_zero = const_time_eq(crypto_bignum_is_zero(t1), 1);
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/* t = m^(p-2) modulo p */
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if (crypto_bignum_sub(prime, two, t2) < 0 ||
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crypto_bignum_exptmod(t1, t2, prime, t) < 0)
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goto fail;
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debug_print_bignum("SSWU: t", t, prime_len);
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/* b / (z * a) */
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if (crypto_bignum_mulmod(z, a, prime, t1) < 0 ||
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crypto_bignum_inverse(t1, prime, t1) < 0 ||
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crypto_bignum_mulmod(b, t1, prime, x1a) < 0)
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goto fail;
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debug_print_bignum("SSWU: x1a = b / (z * a)", x1a, prime_len);
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/* (-b/a) * (1 + t) */
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if (crypto_bignum_sub(prime, b, t1) < 0 ||
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crypto_bignum_inverse(a, prime, t2) < 0 ||
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crypto_bignum_mulmod(t1, t2, prime, t1) < 0 ||
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crypto_bignum_addmod(one, t, prime, t2) < 0 ||
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crypto_bignum_mulmod(t1, t2, prime, x1b) < 0)
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goto fail;
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debug_print_bignum("SSWU: x1b = (-b/a) * (1 + t)", x1b, prime_len);
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/* x1 = CSEL(CEQ(m, 0), x1a, x1b) */
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if (crypto_bignum_to_bin(x1a, bin1, sizeof(bin1), prime_len) < 0 ||
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crypto_bignum_to_bin(x1b, bin2, sizeof(bin2), prime_len) < 0)
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goto fail;
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const_time_select_bin(m_is_zero, bin1, bin2, prime_len, bin);
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x1 = crypto_bignum_init_set(bin, prime_len);
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debug_print_bignum("SSWU: x1 = CSEL(l, x1a, x1b)", x1, prime_len);
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/* gx1 = x1^3 + a * x1 + b */
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if (crypto_bignum_exptmod(x1, three, prime, t1) < 0 ||
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crypto_bignum_mulmod(a, x1, prime, t2) < 0 ||
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crypto_bignum_addmod(t1, t2, prime, t1) < 0 ||
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crypto_bignum_addmod(t1, b, prime, gx1) < 0)
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goto fail;
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debug_print_bignum("SSWU: gx1 = x1^3 + a * x1 + b", gx1, prime_len);
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/* x2 = z * u^2 * x1 */
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if (crypto_bignum_mulmod(z, u2, prime, t1) < 0 ||
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crypto_bignum_mulmod(t1, x1, prime, x2) < 0)
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goto fail;
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debug_print_bignum("SSWU: x2 = z * u^2 * x1", x2, prime_len);
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/* gx2 = x2^3 + a * x2 + b */
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if (crypto_bignum_exptmod(x2, three, prime, t1) < 0 ||
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crypto_bignum_mulmod(a, x2, prime, t2) < 0 ||
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crypto_bignum_addmod(t1, t2, prime, t1) < 0 ||
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crypto_bignum_addmod(t1, b, prime, gx2) < 0)
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goto fail;
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debug_print_bignum("SSWU: gx2 = x2^3 + a * x2 + b", gx2, prime_len);
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/* l = gx1 is a quadratic residue modulo p
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* --> gx1^((p-1)/2) modulo p is zero or one */
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if (crypto_bignum_sub(prime, one, t1) < 0 ||
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crypto_bignum_rshift(t1, 1, t1) < 0 ||
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crypto_bignum_exptmod(gx1, t1, prime, t1) < 0)
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goto fail;
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debug_print_bignum("SSWU: gx1^((p-1)/2) modulo p", t1, prime_len);
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is_qr = const_time_eq(crypto_bignum_is_zero(t1) |
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crypto_bignum_is_one(t1), 1);
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/* v = CSEL(l, gx1, gx2) */
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if (crypto_bignum_to_bin(gx1, bin1, sizeof(bin1), prime_len) < 0 ||
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crypto_bignum_to_bin(gx2, bin2, sizeof(bin2), prime_len) < 0)
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goto fail;
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const_time_select_bin(is_qr, bin1, bin2, prime_len, bin);
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v = crypto_bignum_init_set(bin, prime_len);
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debug_print_bignum("SSWU: v = CSEL(l, gx1, gx2)", v, prime_len);
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/* x = CSEL(l, x1, x2) */
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if (crypto_bignum_to_bin(x1, bin1, sizeof(bin1), prime_len) < 0 ||
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crypto_bignum_to_bin(x2, bin2, sizeof(bin2), prime_len) < 0)
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goto fail;
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const_time_select_bin(is_qr, bin1, bin2, prime_len, x_y);
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wpa_hexdump_key(MSG_DEBUG, "SSWU: x = CSEL(l, x1, x2)", x_y, prime_len);
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/* y = sqrt(v) */
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y = crypto_bignum_init();
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/* TODO: Remove p = 3 mod 4 check and disable group 26 instead(?) */
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if (crypto_bignum_to_bin(prime, bin1, sizeof(bin1), prime_len) < 0)
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goto fail;
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if ((bin1[prime_len - 1] & 0x03) == 3) {
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/* For prime p such that p = 3 mod 4 --> v^((p+1)/4) */
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if (!y ||
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crypto_bignum_add(prime, one, t1) < 0 ||
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crypto_bignum_rshift(t1, 2, t1) < 0 ||
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crypto_bignum_exptmod(v, t1, prime, y) < 0)
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goto fail;
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} else {
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wpa_printf(MSG_DEBUG, "SSWU: prime does not have p = 3 mod 4");
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if (!y || crypto_bignum_sqrtmod(v, prime, y) < 0)
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goto fail;
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}
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debug_print_bignum("SSWU: y = sqrt(v)", y, prime_len);
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/* l = CEQ(LSB(u), LSB(y)) */
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if (crypto_bignum_to_bin(u, bin1, sizeof(bin1), prime_len) < 0 ||
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crypto_bignum_to_bin(y, bin2, sizeof(bin2), prime_len) < 0)
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goto fail;
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is_eq = const_time_eq(bin1[prime_len - 1] & 0x01,
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bin2[prime_len - 1] & 0x01);
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/* P = CSEL(l, (x,y), (x, p-y)) */
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if (crypto_bignum_sub(prime, y, t1) < 0)
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goto fail;
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debug_print_bignum("SSWU: p - y", t1, prime_len);
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if (crypto_bignum_to_bin(y, bin1, sizeof(bin1), prime_len) < 0 ||
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crypto_bignum_to_bin(t1, bin2, sizeof(bin2), prime_len) < 0)
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goto fail;
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const_time_select_bin(is_eq, bin1, bin2, prime_len, &x_y[prime_len]);
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/* output P */
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wpa_hexdump_key(MSG_DEBUG, "SSWU: P.x", x_y, prime_len);
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wpa_hexdump_key(MSG_DEBUG, "SSWU: P.y", &x_y[prime_len], prime_len);
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p = crypto_ec_point_from_bin(ec, x_y);
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fail:
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crypto_bignum_deinit(u2, 1);
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crypto_bignum_deinit(t1, 1);
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crypto_bignum_deinit(t2, 1);
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crypto_bignum_deinit(z, 0);
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crypto_bignum_deinit(t, 1);
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crypto_bignum_deinit(x1a, 1);
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crypto_bignum_deinit(x1b, 1);
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crypto_bignum_deinit(x1, 1);
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crypto_bignum_deinit(x2, 1);
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crypto_bignum_deinit(gx1, 1);
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crypto_bignum_deinit(gx2, 1);
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crypto_bignum_deinit(y, 1);
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crypto_bignum_deinit(v, 1);
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crypto_bignum_deinit(zero, 0);
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crypto_bignum_deinit(one, 0);
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crypto_bignum_deinit(two, 0);
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crypto_bignum_deinit(three, 0);
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forced_memzero(bin, sizeof(bin));
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forced_memzero(bin1, sizeof(bin1));
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forced_memzero(bin2, sizeof(bin2));
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forced_memzero(x_y, sizeof(x_y));
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return p;
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}
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static int sae_pwd_seed(size_t hash_len, const u8 *ssid, size_t ssid_len,
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const u8 *password, size_t password_len,
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const char *identifier, u8 *pwd_seed)
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{
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const u8 *addr[2];
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size_t len[2];
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size_t num_elem;
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/* pwd-seed = HKDF-Extract(ssid, password [ || identifier ]) */
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addr[0] = password;
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len[0] = password_len;
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num_elem = 1;
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wpa_hexdump_ascii(MSG_DEBUG, "SAE: SSID", ssid, ssid_len);
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wpa_hexdump_ascii_key(MSG_DEBUG, "SAE: password",
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password, password_len);
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if (identifier) {
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wpa_printf(MSG_DEBUG, "SAE: password identifier: %s",
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identifier);
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addr[num_elem] = (const u8 *) identifier;
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len[num_elem] = os_strlen(identifier);
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num_elem++;
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}
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if (hkdf_extract(hash_len, ssid, ssid_len, num_elem, addr, len,
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pwd_seed) < 0)
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return -1;
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wpa_hexdump_key(MSG_DEBUG, "SAE: pwd-seed", pwd_seed, hash_len);
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return 0;
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}
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size_t sae_ecc_prime_len_2_hash_len(size_t prime_len)
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{
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if (prime_len <= 256 / 8)
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return 32;
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if (prime_len <= 384 / 8)
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return 48;
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return 64;
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}
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struct crypto_ec_point *
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sae_derive_pt_ecc(struct crypto_ec *ec, int group,
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const u8 *ssid, size_t ssid_len,
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const u8 *password, size_t password_len,
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const char *identifier)
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{
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u8 pwd_seed[64];
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u8 pwd_value[SAE_MAX_ECC_PRIME_LEN * 2];
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size_t pwd_value_len, hash_len, prime_len;
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const struct crypto_bignum *prime;
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struct crypto_bignum *bn = NULL;
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struct crypto_ec_point *p1 = NULL, *p2 = NULL, *pt = NULL;
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prime = crypto_ec_get_prime(ec);
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prime_len = crypto_ec_prime_len(ec);
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if (prime_len > SAE_MAX_ECC_PRIME_LEN)
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goto fail;
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hash_len = sae_ecc_prime_len_2_hash_len(prime_len);
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/* len = olen(p) + ceil(olen(p)/2) */
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pwd_value_len = prime_len + (prime_len + 1) / 2;
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if (sae_pwd_seed(hash_len, ssid, ssid_len, password, password_len,
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identifier, pwd_seed) < 0)
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goto fail;
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/* 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);
|
||||
|
||||
/* 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;
|
||||
|
||||
/* 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;
|
||||
}
|
||||
|
||||
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;
|
||||
}
|
||||
|
||||
|
||||
size_t sae_ffc_prime_len_2_hash_len(size_t prime_len)
|
||||
{
|
||||
if (prime_len <= 2048 / 8)
|
||||
return 32;
|
||||
if (prime_len <= 3072 / 8)
|
||||
return 48;
|
||||
return 64;
|
||||
}
|
||||
|
||||
|
||||
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)
|
||||
{
|
||||
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);
|
||||
|
||||
/* 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 (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)
|
||||
{
|
||||
|
|
@ -605,10 +1347,66 @@ int sae_prepare_commit(const u8 *addr1, const u8 *addr2,
|
|||
identifier) < 0) ||
|
||||
(sae->tmp->dh && sae_derive_pwe_ffc(sae, addr1, addr2, password,
|
||||
password_len,
|
||||
identifier) < 0) ||
|
||||
sae_derive_commit(sae) < 0)
|
||||
identifier) < 0))
|
||||
return -1;
|
||||
return 0;
|
||||
|
||||
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);
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||||
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);
|
||||
}
|
||||
|
||||
|
||||
|
|
|
|||
|
|
@ -43,7 +43,20 @@ struct sae_temporary_data {
|
|||
char *pw_id;
|
||||
int vlan_id;
|
||||
u8 bssid[ETH_ALEN];
|
||||
struct wpabuf *own_rejected_groups;
|
||||
struct wpabuf *peer_rejected_groups;
|
||||
unsigned int h2e:1;
|
||||
unsigned int own_addr_higher:1;
|
||||
};
|
||||
|
||||
struct sae_pt {
|
||||
struct sae_pt *next;
|
||||
int group;
|
||||
struct crypto_ec *ec;
|
||||
struct crypto_ec_point *ecc_pt;
|
||||
|
||||
const struct dh_group *dh;
|
||||
struct crypto_bignum *ffc_pt;
|
||||
};
|
||||
|
||||
enum sae_state {
|
||||
|
|
@ -69,6 +82,9 @@ void sae_clear_data(struct sae_data *sae);
|
|||
int sae_prepare_commit(const u8 *addr1, const u8 *addr2,
|
||||
const u8 *password, size_t password_len,
|
||||
const char *identifier, struct sae_data *sae);
|
||||
int sae_prepare_commit_pt(struct sae_data *sae, const struct sae_pt *pt,
|
||||
const u8 *addr1, const u8 *addr2,
|
||||
int *rejected_groups);
|
||||
int sae_process_commit(struct sae_data *sae);
|
||||
void sae_write_commit(struct sae_data *sae, struct wpabuf *buf,
|
||||
const struct wpabuf *token, const char *identifier);
|
||||
|
|
@ -79,5 +95,15 @@ void sae_write_confirm(struct sae_data *sae, struct wpabuf *buf);
|
|||
int sae_check_confirm(struct sae_data *sae, const u8 *data, size_t len);
|
||||
u16 sae_group_allowed(struct sae_data *sae, int *allowed_groups, u16 group);
|
||||
const char * sae_state_txt(enum sae_state state);
|
||||
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 crypto_ec_point *
|
||||
sae_derive_pwe_from_pt_ecc(const struct sae_pt *pt,
|
||||
const u8 *addr1, const u8 *addr2);
|
||||
struct crypto_bignum *
|
||||
sae_derive_pwe_from_pt_ffc(const struct sae_pt *pt,
|
||||
const u8 *addr1, const u8 *addr2);
|
||||
void sae_deinit_pt(struct sae_pt *pt);
|
||||
|
||||
#endif /* SAE_H */
|
||||
|
|
|
|||
Loading…
Reference in a new issue