sae: refactor and add function sae_calculate_keys

Refactor code by moving code to the new function sae_calculate_keys.
This will make it easier in the next commits to add SAE support for AP
mode.
This commit is contained in:
John Brandt 2024-05-05 17:30:28 -07:00 committed by Denis Kenzior
parent 49cddea10b
commit 2e80a09184
1 changed files with 49 additions and 36 deletions

View File

@ -682,10 +682,8 @@ static bool sae_send_confirm(struct sae_sm *sm)
return true;
}
static int sae_process_commit(struct sae_sm *sm, const uint8_t *from,
const uint8_t *frame, size_t len)
static int sae_calculate_keys(struct sae_sm *sm)
{
uint8_t *ptr = (uint8_t *) frame;
unsigned int nbytes = l_ecc_curve_get_scalar_bytes(sm->curve);
enum l_checksum_type hash =
crypto_sae_hash_from_ecc_prime_len(sm->sae_type, nbytes);
@ -701,39 +699,6 @@ static int sae_process_commit(struct sae_sm *sm, const uint8_t *from,
struct l_ecc_scalar *tmp_scalar;
struct l_ecc_scalar *order;
ptr += 2;
sm->p_scalar = l_ecc_scalar_new(sm->curve, ptr, nbytes);
if (!sm->p_scalar) {
l_error("Server sent invalid P_Scalar during commit");
return sae_reject(sm, SAE_STATE_COMMITTED,
MMPDU_STATUS_CODE_UNSUPP_FINITE_CYCLIC_GROUP);
}
ptr += nbytes;
sm->p_element = l_ecc_point_from_data(sm->curve, L_ECC_POINT_TYPE_FULL,
ptr, nbytes * 2);
if (!sm->p_element) {
l_error("Server sent invalid P_Element during commit");
return sae_reject(sm, SAE_STATE_COMMITTED,
MMPDU_STATUS_CODE_UNSUPP_FINITE_CYCLIC_GROUP);
}
/*
* If they match those sent as part of the protocol instance's own
* SAE Commit message, the frame shall be silently discarded (because
* it is evidence of a reflection attack) and the t0 (retransmission)
* timer shall be set.
*/
if (l_ecc_scalars_are_equal(sm->p_scalar, sm->scalar) ||
l_ecc_points_are_equal(sm->p_element, sm->element)) {
l_warn("peer scalar or element matched own, discarding frame");
return -ENOMSG;
}
sm->sc++;
/*
* K = scalar-op(rand, (element-op(scalar-op(peer-commit-scalar, PWE),
* PEER-COMMIT-ELEMENT)))
@ -822,6 +787,54 @@ static int sae_process_commit(struct sae_sm *sm, const uint8_t *from,
/* don't set the handshakes pmkid until confirm is verified */
memcpy(sm->pmkid, tmp, 16);
return 0;
}
static int sae_process_commit(struct sae_sm *sm, const uint8_t *from,
const uint8_t *frame, size_t len)
{
uint8_t *ptr = (uint8_t *) frame;
unsigned int nbytes = l_ecc_curve_get_scalar_bytes(sm->curve);
int r;
ptr += 2;
sm->p_scalar = l_ecc_scalar_new(sm->curve, ptr, nbytes);
if (!sm->p_scalar) {
l_error("Server sent invalid P_Scalar during commit");
return sae_reject(sm, SAE_STATE_COMMITTED,
MMPDU_STATUS_CODE_UNSUPP_FINITE_CYCLIC_GROUP);
}
ptr += nbytes;
sm->p_element = l_ecc_point_from_data(sm->curve, L_ECC_POINT_TYPE_FULL,
ptr, nbytes * 2);
if (!sm->p_element) {
l_error("Server sent invalid P_Element during commit");
return sae_reject(sm, SAE_STATE_COMMITTED,
MMPDU_STATUS_CODE_UNSUPP_FINITE_CYCLIC_GROUP);
}
/*
* If they match those sent as part of the protocol instance's own
* SAE Commit message, the frame shall be silently discarded (because
* it is evidence of a reflection attack) and the t0 (retransmission)
* timer shall be set.
*/
if (l_ecc_scalars_are_equal(sm->p_scalar, sm->scalar) ||
l_ecc_points_are_equal(sm->p_element, sm->element)) {
l_warn("peer scalar or element matched own, discarding frame");
return -ENOMSG;
}
sm->sc++;
r = sae_calculate_keys(sm);
if (r != 0)
return r;
if (!sae_send_confirm(sm))
return -EPROTO;