dearsky/pico-fido
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Fix computing HMAC of key path.

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Signed-off-by: Pol Henarejos <pol.henarejos@cttc.es>
This commit is contained in:
Pol Henarejos
2022-09-06 21:35:23 +02:00
parent 046706058d
commit dda5c25e85
2 changed files with 14 additions and 6 deletions
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7
src/fido/cmd_authenticate.c
View File

@@ -53,9 +53,12 @@ int cmd_authenticate() {
mbedtls_ecdsa_free(&key); mbedtls_ecdsa_free(&key);
if (ret != 0) if (ret != 0)
return SW_WRONG_DATA(); return SW_WRONG_DATA();
ret = mbedtls_md_hmac(mbedtls_md_info_from_type(MBEDTLS_MD_SHA256), d, 32, req->appId, 32, hmac); uint8_t key_base[U2F_APPID_SIZE + KEY_PATH_LEN];
memcpy(key_base, req->appId, U2F_APPID_SIZE);
memcpy(key_base + U2F_APPID_SIZE, req->keyHandle, KEY_PATH_LEN);
ret = mbedtls_md_hmac(mbedtls_md_info_from_type(MBEDTLS_MD_SHA256), d, 32, key_base, sizeof(key_base), hmac);
mbedtls_platform_zeroize(d, sizeof(d)); mbedtls_platform_zeroize(d, sizeof(d));
if (memcmp(req->keyHandle + 32, hmac, sizeof(hmac)) != 0) if (memcmp(req->keyHandle + KEY_HANDLE_LEN, hmac, sizeof(hmac)) != 0)
return SW_WRONG_DATA(); return SW_WRONG_DATA();
return SW_CONDITIONS_NOT_SATISFIED(); return SW_CONDITIONS_NOT_SATISFIED();
} }

13
src/fido/fido.c
View File

@@ -111,10 +111,15 @@ int derive_key(const uint8_t *app_id, bool new_key, uint8_t *key_handle, mbedtls
return r; return r;
} }
} }
if (new_key == true && (r = mbedtls_md_hmac(mbedtls_md_info_from_type(MBEDTLS_MD_SHA256), outk, 32, app_id, 32, key_handle + 32)) != 0) if (new_key == true) {
{ uint8_t key_base[U2F_APPID_SIZE + KEY_PATH_LEN];
mbedtls_platform_zeroize(outk, sizeof(outk)); memcpy(key_base, app_id, U2F_APPID_SIZE);
return r; memcpy(key_base + U2F_APPID_SIZE, key_handle, KEY_PATH_LEN);
if ((r = mbedtls_md_hmac(mbedtls_md_info_from_type(MBEDTLS_MD_SHA256), outk, 32, key_base, sizeof(key_base), key_handle + 32)) != 0)
{
mbedtls_platform_zeroize(outk, sizeof(outk));
return r;
}
} }
if (key != NULL) { if (key != NULL) {
mbedtls_ecp_group_load(&key->grp, MBEDTLS_ECP_DP_SECP256R1); mbedtls_ecp_group_load(&key->grp, MBEDTLS_ECP_DP_SECP256R1);