mirror of
https://git.kernel.org/pub/scm/network/wireless/iwd.git
synced 2024-11-22 14:49:24 +01:00
sae: update SAE to use ELL API's
This commit is contained in:
James Prestwood
Denis Kenzior
parent
1d66ee0dd5
commit
48f5a051bc
421
src/sae.c
421
src/sae.c
@ -27,7 +27,6 @@
|
||||
#include "src/handshake.h"
|
||||
#include "src/crypto.h"
|
||||
#include "src/mpdu.h"
|
||||
#include "src/ecc.h"
|
||||
#include "src/sae.h"
|
||||
|
||||
#define SAE_RETRANSMIT_TIMEOUT 2
|
||||
@ -42,13 +41,14 @@ enum sae_state {
|
||||
|
||||
struct sae_sm {
|
||||
struct handshake_state *handshake;
|
||||
struct ecc_point pwe;
|
||||
struct l_ecc_point *pwe;
|
||||
enum sae_state state;
|
||||
uint64_t rand[NUM_ECC_DIGITS];
|
||||
uint64_t scalar[NUM_ECC_DIGITS];
|
||||
uint64_t p_scalar[NUM_ECC_DIGITS];
|
||||
struct ecc_point element;
|
||||
struct ecc_point p_element;
|
||||
const struct l_ecc_curve *curve;
|
||||
struct l_ecc_scalar *rand;
|
||||
struct l_ecc_scalar *scalar;
|
||||
struct l_ecc_scalar *p_scalar;
|
||||
struct l_ecc_point *element;
|
||||
struct l_ecc_point *p_element;
|
||||
uint16_t send_confirm;
|
||||
uint8_t kck[32];
|
||||
uint8_t pmk[32];
|
||||
@ -69,60 +69,6 @@ struct sae_sm {
|
||||
void *user_data;
|
||||
};
|
||||
|
||||
static uint64_t curve_p[NUM_ECC_DIGITS] = CURVE_P_32;
|
||||
static uint64_t curve_n[NUM_ECC_DIGITS] = CURVE_N_32;
|
||||
|
||||
/* calculate random quadratic residue */
|
||||
static void sae_get_qr(uint64_t *qr)
|
||||
{
|
||||
l_getrandom(qr, 32);
|
||||
|
||||
while (vli_legendre(qr, curve_p) != -1)
|
||||
l_getrandom(qr, 32);
|
||||
}
|
||||
|
||||
/* calculate random quadratic non-residue */
|
||||
static void sae_get_qnr(uint64_t *qnr)
|
||||
{
|
||||
l_getrandom(qnr, 32);
|
||||
|
||||
while (vli_legendre(qnr, curve_p) != 1)
|
||||
l_getrandom(qnr, 32);
|
||||
}
|
||||
|
||||
/* blinding technique to determine if 'value' is quadratic residue */
|
||||
static bool sae_is_quadratic_residue(uint64_t *value, uint64_t *qr,
|
||||
uint64_t *qnr)
|
||||
{
|
||||
uint64_t y_sqr[NUM_ECC_DIGITS];
|
||||
uint64_t r[NUM_ECC_DIGITS];
|
||||
uint64_t num[NUM_ECC_DIGITS];
|
||||
|
||||
ecc_compute_y_sqr(y_sqr, value);
|
||||
|
||||
l_getrandom(r, 32);
|
||||
|
||||
while (vli_cmp(r, curve_p) >= 0)
|
||||
l_getrandom(r, 32);
|
||||
|
||||
vli_mod_mult_fast(num, y_sqr, r);
|
||||
vli_mod_mult_fast(num, num, r);
|
||||
|
||||
if (r[0] & 1) {
|
||||
vli_mod_mult_fast(num, num, qr);
|
||||
|
||||
if (vli_legendre(num, curve_p) == -1)
|
||||
return true;
|
||||
} else {
|
||||
vli_mod_mult_fast(num, num, qnr);
|
||||
|
||||
if (vli_legendre(num, curve_p) == 1)
|
||||
return true;
|
||||
}
|
||||
|
||||
return false;
|
||||
}
|
||||
|
||||
static bool sae_pwd_seed(const uint8_t *addr1, const uint8_t *addr2,
|
||||
uint8_t *base, size_t base_len,
|
||||
uint8_t counter, uint8_t *out)
|
||||
@ -141,25 +87,38 @@ static bool sae_pwd_seed(const uint8_t *addr1, const uint8_t *addr2,
|
||||
&counter, 1);
|
||||
}
|
||||
|
||||
static bool sae_pwd_value(uint8_t *pwd_seed, uint64_t *pwd_value)
|
||||
static struct l_ecc_scalar *sae_pwd_value(const struct l_ecc_curve *curve,
|
||||
uint8_t *pwd_seed)
|
||||
{
|
||||
uint64_t prime[NUM_ECC_DIGITS];
|
||||
uint8_t pwd_value[L_ECC_SCALAR_MAX_BYTES];
|
||||
uint8_t prime[L_ECC_SCALAR_MAX_BYTES];
|
||||
ssize_t len;
|
||||
struct l_ecc_scalar *p = l_ecc_curve_get_prime(curve);
|
||||
|
||||
memcpy(prime, curve_p, 32);
|
||||
len = l_ecc_scalar_get_data(p, prime, sizeof(prime));
|
||||
|
||||
ecc_be2native(prime);
|
||||
l_ecc_scalar_free(p);
|
||||
|
||||
return kdf_sha256(pwd_seed, 32, "SAE Hunting and Pecking",
|
||||
strlen("SAE Hunting and Pecking"), prime, 32,
|
||||
pwd_value, 32);
|
||||
if (!kdf_sha256(pwd_seed, 32, "SAE Hunting and Pecking",
|
||||
strlen("SAE Hunting and Pecking"), prime, len,
|
||||
pwd_value, 32))
|
||||
return false;
|
||||
|
||||
return l_ecc_scalar_new(curve, pwd_value, sizeof(pwd_value));
|
||||
}
|
||||
|
||||
/* IEEE 802.11-2016 - Section 12.4.2 Assumptions on SAE */
|
||||
static bool sae_cn(const uint8_t *kck, uint16_t send_confirm,
|
||||
const uint64_t *scalar1, const uint64_t *element1,
|
||||
const uint64_t *scalar2, const uint64_t *element2,
|
||||
struct l_ecc_scalar *scalar1,
|
||||
struct l_ecc_point *element1,
|
||||
struct l_ecc_scalar *scalar2,
|
||||
struct l_ecc_point *element2,
|
||||
uint8_t *confirm)
|
||||
{
|
||||
uint8_t s1[L_ECC_SCALAR_MAX_BYTES];
|
||||
uint8_t s2[L_ECC_SCALAR_MAX_BYTES];
|
||||
uint8_t e1[L_ECC_POINT_MAX_BYTES];
|
||||
uint8_t e2[L_ECC_POINT_MAX_BYTES];
|
||||
struct l_checksum *hmac;
|
||||
struct iovec iov[5];
|
||||
int ret;
|
||||
@ -170,14 +129,14 @@ static bool sae_cn(const uint8_t *kck, uint16_t send_confirm,
|
||||
|
||||
iov[0].iov_base = &send_confirm;
|
||||
iov[0].iov_len = 2;
|
||||
iov[1].iov_base = (void *) scalar1;
|
||||
iov[1].iov_len = 32;
|
||||
iov[2].iov_base = (void *) element1;
|
||||
iov[2].iov_len = 64;
|
||||
iov[3].iov_base = (void *) scalar2;
|
||||
iov[3].iov_len = 32;
|
||||
iov[4].iov_base = (void *) element2;
|
||||
iov[4].iov_len = 64;
|
||||
iov[1].iov_base = (void *) s1;
|
||||
iov[1].iov_len = l_ecc_scalar_get_data(scalar1, s1, sizeof(s1));
|
||||
iov[2].iov_base = (void *) e1;
|
||||
iov[2].iov_len = l_ecc_point_get_data(element1, e1, sizeof(e1));
|
||||
iov[3].iov_base = (void *) s2;
|
||||
iov[3].iov_len = l_ecc_scalar_get_data(scalar2, s2, sizeof(s2));;
|
||||
iov[4].iov_base = (void *) e2;
|
||||
iov[4].iov_len = l_ecc_point_get_data(element2, e2, sizeof(e2));;
|
||||
|
||||
l_checksum_updatev(hmac, iov, 5);
|
||||
|
||||
@ -217,28 +176,89 @@ static void sae_reject_authentication(struct sae_sm *sm, uint16_t reason)
|
||||
sae_authentication_failed(sm, reason);
|
||||
}
|
||||
|
||||
static struct l_ecc_scalar *sae_new_residue(const struct l_ecc_curve *curve,
|
||||
bool residue)
|
||||
{
|
||||
struct l_ecc_scalar *s = l_ecc_scalar_new_random(curve);
|
||||
|
||||
while (l_ecc_scalar_legendre(s) != ((residue) ? -1 : 1)) {
|
||||
l_ecc_scalar_free(s);
|
||||
s = l_ecc_scalar_new_random(curve);
|
||||
}
|
||||
|
||||
return s;
|
||||
}
|
||||
|
||||
static bool sae_is_quadradic_residue(const struct l_ecc_curve *curve,
|
||||
struct l_ecc_scalar *value,
|
||||
struct l_ecc_scalar *qr,
|
||||
struct l_ecc_scalar *qnr)
|
||||
{
|
||||
uint64_t rbuf[L_ECC_MAX_DIGITS];
|
||||
struct l_ecc_scalar *y_sqr = l_ecc_scalar_new(curve, NULL, 0);
|
||||
struct l_ecc_scalar *r = l_ecc_scalar_new_random(curve);
|
||||
struct l_ecc_scalar *num = l_ecc_scalar_new(curve, NULL, 0);
|
||||
size_t bytes;
|
||||
|
||||
l_ecc_scalar_sum_x(y_sqr, value);
|
||||
|
||||
l_ecc_scalar_multiply(num, y_sqr, r);
|
||||
l_ecc_scalar_multiply(num, num, r);
|
||||
|
||||
l_ecc_scalar_free(y_sqr);
|
||||
|
||||
bytes = l_ecc_scalar_get_data(r, rbuf, sizeof(rbuf));
|
||||
l_ecc_scalar_free(r);
|
||||
|
||||
if (bytes <= 0) {
|
||||
l_ecc_scalar_free(num);
|
||||
return false;
|
||||
}
|
||||
|
||||
if (rbuf[bytes / 8] & 1) {
|
||||
l_ecc_scalar_multiply(num, num, qr);
|
||||
|
||||
if (l_ecc_scalar_legendre(num) == -1) {
|
||||
l_ecc_scalar_free(num);
|
||||
return true;
|
||||
}
|
||||
} else {
|
||||
l_ecc_scalar_multiply(num, num, qnr);
|
||||
|
||||
if (l_ecc_scalar_legendre(num) == 1) {
|
||||
l_ecc_scalar_free(num);
|
||||
return true;
|
||||
}
|
||||
}
|
||||
|
||||
l_ecc_scalar_free(num);
|
||||
|
||||
return false;
|
||||
}
|
||||
|
||||
/*
|
||||
* IEEE 802.11-2016 Section 12.4.4.2.2
|
||||
* Generation of the password element with ECC groups
|
||||
*/
|
||||
static bool sae_compute_pwe(char *password, const uint8_t *addr1,
|
||||
const uint8_t *addr2, struct ecc_point *pwe)
|
||||
static bool sae_compute_pwe(struct sae_sm *sm, char *password,
|
||||
const uint8_t *addr1, const uint8_t *addr2)
|
||||
{
|
||||
bool found = false;
|
||||
uint8_t counter = 1;
|
||||
uint8_t k = 20;
|
||||
uint8_t pwd_seed[32];
|
||||
uint64_t pwd_value[NUM_ECC_DIGITS];
|
||||
struct l_ecc_scalar *pwd_value;
|
||||
uint8_t random[32];
|
||||
uint8_t *base = (uint8_t *) password;
|
||||
size_t base_len = strlen(password);
|
||||
uint8_t save[32] = { 0 };
|
||||
uint64_t qr[NUM_ECC_DIGITS];
|
||||
uint64_t qnr[NUM_ECC_DIGITS];
|
||||
struct l_ecc_scalar *qr;
|
||||
struct l_ecc_scalar *qnr;
|
||||
uint8_t x[L_ECC_SCALAR_MAX_BYTES];
|
||||
|
||||
/* create qr/qnr prior to beginning hunting-and-pecking loop */
|
||||
sae_get_qr(qr);
|
||||
sae_get_qnr(qnr);
|
||||
qr = sae_new_residue(sm->curve, true);
|
||||
qnr = sae_new_residue(sm->curve, false);
|
||||
|
||||
do {
|
||||
/* pwd-seed = H(max(addr1, addr2) || min(addr1, addr2),
|
||||
@ -247,87 +267,50 @@ static bool sae_compute_pwe(char *password, const uint8_t *addr1,
|
||||
*/
|
||||
sae_pwd_seed(addr1, addr2, base, base_len, counter, pwd_seed);
|
||||
|
||||
sae_pwd_value(pwd_seed, pwd_value);
|
||||
pwd_value = sae_pwd_value(sm->curve, pwd_seed);
|
||||
|
||||
ecc_be2native(pwd_value);
|
||||
if (sae_is_quadradic_residue(sm->curve, pwd_value, qr, qnr)) {
|
||||
if (found == false) {
|
||||
l_ecc_scalar_get_data(pwd_value, x, sizeof(x));
|
||||
|
||||
/* if (pwd-value < p) { */
|
||||
if (vli_cmp(pwd_value, curve_p) < 0) {
|
||||
if (sae_is_quadratic_residue(pwd_value, qr, qnr)) {
|
||||
if (found == false) {
|
||||
memcpy(pwe->x, pwd_value, 32);
|
||||
memcpy(save, pwd_seed, 32);
|
||||
memcpy(save, pwd_seed, 32);
|
||||
|
||||
l_getrandom(random, 32);
|
||||
base = random;
|
||||
base_len = 32;
|
||||
l_getrandom(random, 32);
|
||||
base = random;
|
||||
base_len = 32;
|
||||
|
||||
found = true;
|
||||
}
|
||||
found = true;
|
||||
}
|
||||
}
|
||||
|
||||
l_ecc_scalar_free(pwd_value);
|
||||
|
||||
counter++;
|
||||
|
||||
} while ((counter <= k) || (found == false));
|
||||
|
||||
l_ecc_scalar_free(qr);
|
||||
l_ecc_scalar_free(qnr);
|
||||
|
||||
if (!found) {
|
||||
l_error("max PWE iterations reached!");
|
||||
return false;
|
||||
}
|
||||
|
||||
if (!ecc_compute_y(pwe->y, pwe->x)) {
|
||||
/* should always return true */
|
||||
if (!(save[31] & 1))
|
||||
sm->pwe = l_ecc_point_from_data(sm->curve,
|
||||
L_ECC_POINT_TYPE_COMPRESSED_BIT1,
|
||||
x, sizeof(x));
|
||||
else
|
||||
sm->pwe = l_ecc_point_from_data(sm->curve,
|
||||
L_ECC_POINT_TYPE_COMPRESSED_BIT0,
|
||||
x, sizeof(x));
|
||||
|
||||
if (!sm->pwe) {
|
||||
l_error("computing y failed, was x quadratic residue?");
|
||||
return false;
|
||||
}
|
||||
|
||||
if ((pwe->y[0] & 1) != (save[31] & 1))
|
||||
vli_mod_sub(pwe->y, curve_p, pwe->y, curve_p);
|
||||
|
||||
return true;
|
||||
}
|
||||
|
||||
/* commit-scalar = (rand + mask) mod r */
|
||||
static void sae_get_commit_scalar(uint64_t *scalar, uint64_t *mask,
|
||||
uint64_t *rand)
|
||||
{
|
||||
uint64_t _1[NUM_ECC_DIGITS] = { 1ull };
|
||||
|
||||
l_getrandom(rand, ECC_BYTES);
|
||||
|
||||
/* ensure 1 < p_rand < r */
|
||||
while (!((vli_cmp(rand, _1) > 0) &&
|
||||
(vli_cmp(rand, curve_n) < 0)))
|
||||
l_getrandom(rand, ECC_BYTES);
|
||||
|
||||
l_getrandom(mask, ECC_BYTES);
|
||||
|
||||
/* ensure 1 < p_mask < r */
|
||||
while (!((vli_cmp(mask, _1) > 0) &&
|
||||
(vli_cmp(mask, curve_n) < 0)))
|
||||
l_getrandom(mask, ECC_BYTES);
|
||||
|
||||
/* (rand + mask) mod r */
|
||||
vli_mod_add(scalar, rand, mask, curve_n);
|
||||
}
|
||||
|
||||
/* commit-element = inv(mask * PWE) */
|
||||
static bool sae_get_commit_element(struct ecc_point *element,
|
||||
struct ecc_point *pwe, uint64_t *mask)
|
||||
{
|
||||
/* p_mask * PWE */
|
||||
ecc_point_mult(element, pwe, mask, NULL, vli_num_bits(mask));
|
||||
|
||||
if (!ecc_valid_point(element))
|
||||
return false;
|
||||
|
||||
/* inv(p_mask * PWE) */
|
||||
vli_sub(element->y, curve_p, element->y);
|
||||
|
||||
if (!ecc_valid_point(element))
|
||||
return false;
|
||||
|
||||
return true;
|
||||
}
|
||||
|
||||
@ -335,10 +318,9 @@ static bool sae_build_commit(struct sae_sm *sm, const uint8_t *addr1,
|
||||
const uint8_t *addr2, uint8_t *commit,
|
||||
size_t *len, bool retry)
|
||||
{
|
||||
uint64_t scalar[NUM_ECC_DIGITS];
|
||||
uint64_t mask[NUM_ECC_DIGITS];
|
||||
struct ecc_point element;
|
||||
struct l_ecc_scalar *mask;
|
||||
uint8_t *ptr = commit;
|
||||
struct l_ecc_scalar *order;
|
||||
|
||||
if (retry)
|
||||
goto old_commit;
|
||||
@ -348,18 +330,28 @@ static bool sae_build_commit(struct sae_sm *sm, const uint8_t *addr1,
|
||||
return false;
|
||||
}
|
||||
|
||||
if (!sae_compute_pwe(sm->handshake->passphrase, addr1,
|
||||
addr2, &sm->pwe)) {
|
||||
if (!sae_compute_pwe(sm, sm->handshake->passphrase, addr1, addr2)) {
|
||||
l_error("could not compute PWE");
|
||||
return false;
|
||||
}
|
||||
|
||||
sae_get_commit_scalar(sm->scalar, mask, sm->rand);
|
||||
sm->scalar = l_ecc_scalar_new(sm->curve, NULL, 0);
|
||||
sm->rand = l_ecc_scalar_new_random(sm->curve);
|
||||
mask = l_ecc_scalar_new_random(sm->curve);
|
||||
|
||||
if (!sae_get_commit_element(&sm->element, &sm->pwe, mask)) {
|
||||
l_error("error calculating commit element");
|
||||
return false;
|
||||
}
|
||||
order = l_ecc_curve_get_order(sm->curve);
|
||||
|
||||
/* commit-scalar = (rand + mask) mod r */
|
||||
l_ecc_scalar_add(sm->scalar, sm->rand, mask, order);
|
||||
|
||||
l_ecc_scalar_free(order);
|
||||
|
||||
/* commit-element = inv(mask * PWE) */
|
||||
sm->element = l_ecc_point_new(sm->curve);
|
||||
l_ecc_point_multiply(sm->element, mask, sm->pwe);
|
||||
l_ecc_point_inverse(sm->element);
|
||||
|
||||
l_ecc_scalar_free(mask);
|
||||
|
||||
/*
|
||||
* Several cases require retransmitting the same commit message. The
|
||||
@ -367,13 +359,6 @@ static bool sae_build_commit(struct sae_sm *sm, const uint8_t *addr1,
|
||||
* timeout.
|
||||
*/
|
||||
old_commit:
|
||||
memcpy(scalar, sm->scalar, 32);
|
||||
memcpy(element.x, sm->element.x, 32);
|
||||
memcpy(element.y, sm->element.y, 32);
|
||||
|
||||
ecc_native2be(scalar);
|
||||
ecc_native2be(element.x);
|
||||
ecc_native2be(element.y);
|
||||
|
||||
/* transaction */
|
||||
l_put_le16(1, ptr);
|
||||
@ -390,12 +375,8 @@ old_commit:
|
||||
ptr += sm->token_len;
|
||||
}
|
||||
|
||||
memcpy(ptr, scalar, 32);
|
||||
ptr += 32;
|
||||
memcpy(ptr, element.x, 32);
|
||||
ptr += 32;
|
||||
memcpy(ptr, element.y, 32);
|
||||
ptr += 32;
|
||||
ptr += l_ecc_scalar_get_data(sm->scalar, ptr, L_ECC_SCALAR_MAX_BYTES);
|
||||
ptr += l_ecc_point_get_data(sm->element, ptr, L_ECC_POINT_MAX_BYTES);
|
||||
|
||||
*len = ptr - commit;
|
||||
|
||||
@ -408,30 +389,12 @@ static void sae_send_confirm(struct sae_sm *sm)
|
||||
uint8_t body[38];
|
||||
uint8_t *ptr = body;
|
||||
|
||||
ecc_native2be(sm->scalar);
|
||||
ecc_native2be(sm->element.x);
|
||||
ecc_native2be(sm->element.y);
|
||||
ecc_native2be(sm->p_scalar);
|
||||
ecc_native2be(sm->p_element.x);
|
||||
ecc_native2be(sm->p_element.y);
|
||||
|
||||
/*
|
||||
* confirm = CN(KCK, send-confirm, commit-scalar, COMMIT-ELEMENT,
|
||||
* peer-commit-scalar, PEER-COMMIT-ELEMENT)
|
||||
*/
|
||||
sae_cn(sm->kck, sm->sc, sm->scalar, (uint64_t *) &sm->element,
|
||||
sm->p_scalar, (uint64_t *) &sm->p_element, confirm);
|
||||
|
||||
/*
|
||||
* in case of retransmition, we will need to reuse these values, so
|
||||
* go back to native endianness for consistency.
|
||||
*/
|
||||
ecc_be2native(sm->scalar);
|
||||
ecc_be2native(sm->element.x);
|
||||
ecc_be2native(sm->element.y);
|
||||
ecc_be2native(sm->p_scalar);
|
||||
ecc_be2native(sm->p_element.x);
|
||||
ecc_be2native(sm->p_element.y);
|
||||
sae_cn(sm->kck, sm->sc, sm->scalar, sm->element, sm->p_scalar,
|
||||
sm->p_element, confirm);
|
||||
|
||||
l_put_le16(2, ptr);
|
||||
ptr += 2;
|
||||
@ -451,14 +414,17 @@ static void sae_process_commit(struct sae_sm *sm, const uint8_t *from,
|
||||
const uint8_t *frame, size_t len)
|
||||
{
|
||||
uint8_t *ptr = (uint8_t *) frame;
|
||||
uint64_t k[NUM_ECC_DIGITS];
|
||||
struct ecc_point k_point;
|
||||
uint8_t k[L_ECC_SCALAR_MAX_BYTES];
|
||||
struct l_ecc_point *k_point;
|
||||
uint8_t zero_key[32] = { 0 };
|
||||
uint8_t keyseed[32];
|
||||
uint8_t kck_and_pmk[2][32];
|
||||
uint64_t tmp[NUM_ECC_DIGITS];
|
||||
uint8_t tmp[L_ECC_SCALAR_MAX_BYTES];
|
||||
struct l_ecc_scalar *tmp_scalar;
|
||||
uint16_t group;
|
||||
uint16_t reason = MMPDU_REASON_CODE_UNSPECIFIED;
|
||||
ssize_t klen;
|
||||
struct l_ecc_scalar *order;
|
||||
|
||||
if (sm->state != SAE_STATE_COMMITTED) {
|
||||
l_error("bad state %u", sm->state);
|
||||
@ -479,19 +445,14 @@ static void sae_process_commit(struct sae_sm *sm, const uint8_t *from,
|
||||
goto reject;
|
||||
}
|
||||
|
||||
memcpy(sm->p_scalar, ptr, 32);
|
||||
sm->p_scalar = l_ecc_scalar_new(sm->curve, ptr, 32);
|
||||
ptr += 32;
|
||||
memcpy(sm->p_element.x, ptr, 32);
|
||||
ptr += 32;
|
||||
memcpy(sm->p_element.y, ptr, 32);
|
||||
|
||||
ecc_be2native(sm->p_scalar);
|
||||
ecc_be2native(sm->p_element.x);
|
||||
ecc_be2native(sm->p_element.y);
|
||||
sm->p_element = l_ecc_point_from_data(sm->curve, L_ECC_POINT_TYPE_FULL,
|
||||
ptr, 64);
|
||||
|
||||
if (!memcmp(sm->p_scalar, sm->scalar, 32) ||
|
||||
!memcmp(sm->p_element.x, sm->element.x, 32) ||
|
||||
!memcmp(sm->p_element.y, sm->element.y, 32)) {
|
||||
if (l_ecc_scalars_are_equal(sm->p_scalar, sm->scalar) ||
|
||||
l_ecc_points_are_equal(sm->p_element, sm->element)) {
|
||||
/* possible reflection attack, silently discard message */
|
||||
l_warn("peer scalar or element matched own, discarding frame");
|
||||
|
||||
@ -504,17 +465,16 @@ static void sae_process_commit(struct sae_sm *sm, const uint8_t *from,
|
||||
* K = scalar-op(rand, (element-op(scalar-op(peer-commit-scalar, PWE),
|
||||
* PEER-COMMIT-ELEMENT)))
|
||||
*/
|
||||
k_point = l_ecc_point_new(sm->curve);
|
||||
|
||||
/* k_point = scalar-op(peer-commit-scalar, PWE) */
|
||||
ecc_point_mult(&k_point, &sm->pwe, sm->p_scalar, NULL,
|
||||
vli_num_bits(sm->p_scalar));
|
||||
l_ecc_point_multiply(k_point, sm->p_scalar, sm->pwe);
|
||||
|
||||
/* k_point = element-op(k_point, PEER-COMMIT-ELEMENT) */
|
||||
ecc_point_add(&k_point, &k_point, &sm->p_element);
|
||||
l_ecc_point_add(k_point, k_point, sm->p_element);
|
||||
|
||||
/* k_point = scalar-op(rand, k_point) */
|
||||
ecc_point_mult(&k_point, &k_point, sm->rand, NULL,
|
||||
vli_num_bits(sm->rand));
|
||||
l_ecc_point_multiply(k_point, sm->rand, k_point);
|
||||
|
||||
/*
|
||||
* IEEE 802.11-2016 - Section 12.4.4.2.1 ECC group definition
|
||||
@ -522,20 +482,22 @@ static void sae_process_commit(struct sae_sm *sm, const uint8_t *from,
|
||||
* point (x, y) that satisfies the curve equation to its x-coordinate—
|
||||
* i.e., if P = (x, y) then F(P) = x.
|
||||
*/
|
||||
memcpy(k, k_point.x, 32);
|
||||
klen = l_ecc_point_get_x(k_point, k, sizeof(k));
|
||||
|
||||
ecc_native2be(k);
|
||||
l_ecc_point_free(k_point);
|
||||
|
||||
/* keyseed = H(<0>32, k) */
|
||||
hmac_sha256(zero_key, 32, k, 32, keyseed, 32);
|
||||
hmac_sha256(zero_key, 32, k, klen, keyseed, 32);
|
||||
|
||||
/*
|
||||
* kck_and_pmk = KDF-Hash-512(keyseed, "SAE KCK and PMK",
|
||||
(commit-scalar + peer-commit-scalar) mod r)
|
||||
*/
|
||||
vli_mod_add(tmp, sm->p_scalar, sm->scalar, curve_n);
|
||||
tmp_scalar = l_ecc_scalar_new(sm->curve, NULL, 0);
|
||||
order = l_ecc_curve_get_order(sm->curve);
|
||||
|
||||
ecc_native2be(tmp);
|
||||
l_ecc_scalar_add(tmp_scalar, sm->p_scalar, sm->scalar, order);
|
||||
l_ecc_scalar_get_data(tmp_scalar, tmp, sizeof(tmp));
|
||||
|
||||
kdf_sha256(keyseed, 32, "SAE KCK and PMK", strlen("SAE KCK and PMK"),
|
||||
tmp, 32, kck_and_pmk, 64);
|
||||
@ -546,8 +508,12 @@ static void sae_process_commit(struct sae_sm *sm, const uint8_t *from,
|
||||
/*
|
||||
* PMKID = L((commit-scalar + peer-commit-scalar) mod r, 0, 128)
|
||||
*/
|
||||
vli_mod_add(tmp, sm->scalar, sm->p_scalar, curve_n);
|
||||
ecc_native2be(tmp);
|
||||
l_ecc_scalar_add(tmp_scalar, sm->scalar, sm->p_scalar, order);
|
||||
l_ecc_scalar_get_data(tmp_scalar, tmp, sizeof(tmp));
|
||||
|
||||
l_ecc_scalar_free(order);
|
||||
|
||||
l_ecc_scalar_free(tmp_scalar);
|
||||
/* don't set the handshakes pmkid until confirm is verified */
|
||||
memcpy(sm->pmkid, tmp, 16);
|
||||
|
||||
@ -564,23 +530,8 @@ static bool sae_verify_confirm(struct sae_sm *sm, const uint8_t *frame)
|
||||
uint8_t check[32];
|
||||
uint16_t rc = l_get_le16(frame);
|
||||
|
||||
ecc_native2be(sm->scalar);
|
||||
ecc_native2be(sm->element.x);
|
||||
ecc_native2be(sm->element.y);
|
||||
ecc_native2be(sm->p_scalar);
|
||||
ecc_native2be(sm->p_element.x);
|
||||
ecc_native2be(sm->p_element.y);
|
||||
|
||||
sae_cn(sm->kck, rc, sm->p_scalar,
|
||||
(const uint64_t *) &sm->p_element, sm->scalar,
|
||||
(const uint64_t *) &sm->element, check);
|
||||
|
||||
ecc_be2native(sm->scalar);
|
||||
ecc_be2native(sm->element.x);
|
||||
ecc_be2native(sm->element.y);
|
||||
ecc_be2native(sm->p_scalar);
|
||||
ecc_be2native(sm->p_element.x);
|
||||
ecc_be2native(sm->p_element.y);
|
||||
sae_cn(sm->kck, rc, sm->p_scalar, sm->p_element, sm->scalar,
|
||||
sm->element, check);
|
||||
|
||||
if (memcmp(frame + 2, check, 32)) {
|
||||
l_error("confirm did not match");
|
||||
@ -978,6 +929,7 @@ struct sae_sm *sae_sm_new(struct handshake_state *hs, sae_tx_packet_func_t tx,
|
||||
sm->user_data = user_data;
|
||||
sm->handshake = hs;
|
||||
sm->state = SAE_STATE_NOTHING;
|
||||
sm->curve = l_ecc_curve_get(19);
|
||||
|
||||
return sm;
|
||||
}
|
||||
@ -986,6 +938,13 @@ void sae_sm_free(struct sae_sm *sm)
|
||||
{
|
||||
l_free(sm->token);
|
||||
|
||||
l_ecc_scalar_free(sm->scalar);
|
||||
l_ecc_scalar_free(sm->p_scalar);
|
||||
l_ecc_scalar_free(sm->rand);
|
||||
l_ecc_point_free(sm->element);
|
||||
l_ecc_point_free(sm->p_element);
|
||||
l_ecc_point_free(sm->pwe);
|
||||
|
||||
/* zero out whole structure, including keys */
|
||||
memset(sm, 0, sizeof(struct sae_sm));
|
||||
|
||||
|
||||
Loading…
Reference in New Issue
Block a user