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Add support for persistentPinUvAuthToken.

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Signed-off-by: Pol Henarejos <pol.henarejos@cttc.es>
This commit is contained in:
Pol Henarejos
2025-08-28 00:17:57 +02:00
parent 2b640a5c36
commit 73a7856866
8 changed files with 117 additions and 66 deletions
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98
src/fido/cbor_client_pin.c
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@@ -105,11 +105,7 @@ int regenerate() {
mbedtls_ecdh_init(&hkey);
hkey_init = true;
mbedtls_ecdh_setup(&hkey, MBEDTLS_ECP_DP_SECP256R1);
int ret = mbedtls_ecdh_gen_public(&hkey.ctx.mbed_ecdh.grp,
&hkey.ctx.mbed_ecdh.d,
&hkey.ctx.mbed_ecdh.Q,
random_gen,
NULL);
int ret = mbedtls_ecdh_gen_public(&hkey.ctx.mbed_ecdh.grp, &hkey.ctx.mbed_ecdh.d, &hkey.ctx.mbed_ecdh.Q, random_gen, NULL);
mbedtls_mpi_lset(&hkey.ctx.mbed_ecdh.Qp.Z, 1);
if (ret != 0) {
return ret;
@@ -125,34 +121,15 @@ int kdf(uint8_t protocol, const mbedtls_mpi *z, uint8_t *sharedSecret) {
return ret;
}
if (protocol == 1) {
return mbedtls_md(mbedtls_md_info_from_type(MBEDTLS_MD_SHA256),
buf,
sizeof(buf),
sharedSecret);
return mbedtls_md(mbedtls_md_info_from_type(MBEDTLS_MD_SHA256), buf, sizeof(buf), sharedSecret);
}
else if (protocol == 2) {
const mbedtls_md_info_t *md_info = mbedtls_md_info_from_type(MBEDTLS_MD_SHA256);
ret = mbedtls_hkdf(md_info,
NULL,
0,
buf,
sizeof(buf),
(uint8_t *) "CTAP2 HMAC key",
14,
sharedSecret,
32);
ret = mbedtls_hkdf(md_info, NULL, 0, buf, sizeof(buf), (uint8_t *) "CTAP2 HMAC key", 14, sharedSecret, 32);
if (ret != 0) {
return ret;
}
return mbedtls_hkdf(md_info,
NULL,
0,
buf,
sizeof(buf),
(uint8_t *) "CTAP2 AES key",
13,
sharedSecret + 32,
32);
return mbedtls_hkdf(md_info, NULL, 0, buf, sizeof(buf), (uint8_t *) "CTAP2 AES key", 13, sharedSecret + 32, 32);
}
return -1;
}
@@ -160,26 +137,38 @@ int kdf(uint8_t protocol, const mbedtls_mpi *z, uint8_t *sharedSecret) {
int ecdh(uint8_t protocol, const mbedtls_ecp_point *Q, uint8_t *sharedSecret) {
mbedtls_mpi z;
mbedtls_mpi_init(&z);
int ret = mbedtls_ecdh_compute_shared(&hkey.ctx.mbed_ecdh.grp,
&z,
Q,
&hkey.ctx.mbed_ecdh.d,
random_gen,
NULL);
int ret = mbedtls_ecdh_compute_shared(&hkey.ctx.mbed_ecdh.grp, &z, Q, &hkey.ctx.mbed_ecdh.d, random_gen, NULL);
ret = kdf(protocol, &z, sharedSecret);
mbedtls_mpi_free(&z);
return ret;
}
int resetPinUvAuthToken() {
void resetAuthToken(bool persistent) {
uint16_t fid = EF_AUTHTOKEN;
if (persistent) {
fid = EF_PAUTHTOKEN;
}
file_t *ef = search_by_fid(fid, NULL, SPECIFY_EF);
uint8_t t[32];
random_gen(NULL, t, sizeof(t));
file_put_data(ef_authtoken, t, sizeof(t));
file_put_data(ef, t, sizeof(t));
low_flash_available();
}
int resetPinUvAuthToken() {
resetAuthToken(false);
paut.permissions = 0;
paut.data = file_get_data(ef_authtoken);
paut.len = file_get_size(ef_authtoken);
return 0;
}
low_flash_available();
int resetPersistentPinUvAuthToken() {
resetAuthToken(true);
file_t *ef_pauthtoken = search_by_fid(EF_PAUTHTOKEN, NULL, SPECIFY_EF);
ppaut.permissions = 0;
ppaut.data = file_get_data(ef_pauthtoken);
ppaut.len = file_get_size(ef_pauthtoken);
return 0;
}
@@ -578,6 +567,7 @@ int cbor_client_pin(const uint8_t *data, size_t len) {
}
low_flash_available();
resetPinUvAuthToken();
resetPersistentPinUvAuthToken();
goto err; // No return
}
else if (subcommand == 0x9 || subcommand == 0x5) { //getPinUvAuthTokenUsingPinWithPermissions
@@ -598,7 +588,9 @@ int cbor_client_pin(const uint8_t *data, size_t len) {
if ((permissions & CTAP_PERMISSION_BE)) { // Not supported yet
CBOR_ERROR(CTAP2_ERR_UNAUTHORIZED_PERMISSION);
}
if ((permissions & CTAP_PERMISSION_PCMR) && permissions != CTAP_PERMISSION_PCMR) {
CBOR_ERROR(CTAP2_ERR_UNAUTHORIZED_PERMISSION);
}
}
if (!file_has_data(ef_pin)) {
CBOR_ERROR(CTAP2_ERR_PIN_NOT_SET);
@@ -664,21 +656,29 @@ int cbor_client_pin(const uint8_t *data, size_t len) {
if (file_has_data(ef_minpin) && file_get_data(ef_minpin)[1] == 1) {
CBOR_ERROR(CTAP2_ERR_PIN_INVALID);
}
resetPinUvAuthToken();
beginUsingPinUvAuthToken(false);
if (subcommand == 0x05) {
permissions = CTAP_PERMISSION_MC | CTAP_PERMISSION_GA;
}
paut.permissions = (uint8_t)permissions;
if (rpId.present == true) {
mbedtls_sha256((uint8_t *) rpId.data, rpId.len, paut.rp_id_hash, 0);
paut.has_rp_id = true;
uint8_t pinUvAuthToken_enc[32 + IV_SIZE], *pdata = NULL;
;
if (permissions & CTAP_PERMISSION_PCMR) {
ppaut.permissions = CTAP_PERMISSION_PCMR;
pdata = ppaut.data;
}
else {
paut.has_rp_id = false;
resetPinUvAuthToken();
beginUsingPinUvAuthToken(false);
if (subcommand == 0x05) {
permissions = CTAP_PERMISSION_MC | CTAP_PERMISSION_GA;
}
paut.permissions = (uint8_t)permissions;
if (rpId.present == true) {
mbedtls_sha256((uint8_t *) rpId.data, rpId.len, paut.rp_id_hash, 0);
paut.has_rp_id = true;
}
else {
paut.has_rp_id = false;
}
pdata = paut.data;
}
uint8_t pinUvAuthToken_enc[32 + IV_SIZE];
encrypt((uint8_t)pinUvAuthProtocol, sharedSecret, paut.data, 32, pinUvAuthToken_enc);
encrypt((uint8_t)pinUvAuthProtocol, sharedSecret, pdata, 32, pinUvAuthToken_enc);
CBOR_CHECK(cbor_encoder_create_map(&encoder, &mapEncoder, 1));
CBOR_CHECK(cbor_encode_uint(&mapEncoder, 0x02));
CBOR_CHECK(cbor_encode_byte_string(&mapEncoder, pinUvAuthToken_enc, 32 + poff));