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Added support for user enforcement and key check (P1 0x07, 0x03 and 0x08).

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Signed-off-by: Pol Henarejos <pol.henarejos@cttc.es>
This commit is contained in:
Pol Henarejos
2022-09-06 16:54:12 +02:00
parent 694ab2cf87
commit 046706058d
1 changed files with 31 additions and 7 deletions
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38
src/fido/cmd_authenticate.c
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@@ -28,8 +28,37 @@ int cmd_authenticate() {
U2F_AUTHENTICATE_RESP *resp = (U2F_AUTHENTICATE_RESP *)res_APDU;
if (scan_files() != CCID_OK)
return SW_EXEC_ERROR();
if (req->keyHandleLen != KEY_HANDLE_LEN)
return SW_WRONG_DATA();
if (P1(apdu) == 0x03 && wait_button_pressed() == true)
return SW_CONDITIONS_NOT_SATISFIED();
mbedtls_ecdsa_context key;
mbedtls_ecdsa_init(&key);
int ret = derive_key(req->appId, false, req->keyHandle, &key);
if (ret != CCID_OK) {
mbedtls_ecdsa_free(&key);
return SW_EXEC_ERROR();
}
if (P1(apdu) == 0x07) {
for (int i = 0; i < KEY_PATH_ENTRIES; i++) {
uint32_t k = *(uint32_t *)&req->keyHandle[i*sizeof(uint32_t)];
if (!(k & 0x80000000)) {
mbedtls_ecdsa_free(&key);
return SW_WRONG_DATA();
}
}
uint8_t hmac[32], d[32];
ret = mbedtls_ecp_write_key(&key, d, sizeof(d));
mbedtls_ecdsa_free(&key);
if (ret != 0)
return SW_WRONG_DATA();
ret = mbedtls_md_hmac(mbedtls_md_info_from_type(MBEDTLS_MD_SHA256), d, 32, req->appId, 32, hmac);
mbedtls_platform_zeroize(d, sizeof(d));
if (memcmp(req->keyHandle + 32, hmac, sizeof(hmac)) != 0)
return SW_WRONG_DATA();
return SW_CONDITIONS_NOT_SATISFIED();
}
resp->flags = 0x1;
resp->ctr[0] = 0;
uint8_t hash[32], sig_base[U2F_APPID_SIZE+1+4+U2F_CHAL_SIZE];
@@ -37,13 +66,8 @@ int cmd_authenticate() {
memcpy(sig_base+U2F_APPID_SIZE, &resp->flags, sizeof(uint8_t));
memcpy(sig_base + U2F_APPID_SIZE + 1, resp->ctr, 4);
memcpy(sig_base + U2F_APPID_SIZE + 1 + 4, req->chal, U2F_CHAL_SIZE);
int ret = mbedtls_md(mbedtls_md_info_from_type(MBEDTLS_MD_SHA256), sig_base, sizeof(sig_base), hash);
if (ret != 0)
return SW_EXEC_ERROR();
mbedtls_ecdsa_context key;
mbedtls_ecdsa_init(&key);
ret = derive_key(req->appId, false, req->keyHandle, &key);
if (ret != CCID_OK) {
ret = mbedtls_md(mbedtls_md_info_from_type(MBEDTLS_MD_SHA256), sig_base, sizeof(sig_base), hash);
if (ret != 0) {
mbedtls_ecdsa_free(&key);
return SW_EXEC_ERROR();
}