solo1/fido2/crypto.c

428 wiersze
10 KiB
C

// Copyright 2019 SoloKeys Developers
//
// Licensed under the Apache License, Version 2.0, <LICENSE-APACHE or
// http://apache.org/licenses/LICENSE-2.0> or the MIT license <LICENSE-MIT or
// http://opensource.org/licenses/MIT>, at your option. This file may not be
// copied, modified, or distributed except according to those terms.
/*
* Wrapper for crypto implementation on device.
*
* Can be replaced with different crypto implementation by
* defining EXTERNAL_SOLO_CRYPTO
*
* */
#ifndef EXTERNAL_SOLO_CRYPTO
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "util.h"
#include "crypto.h"
#include "sha256.h"
#include "uECC.h"
#include "aes.h"
#include "ctap.h"
#include "device.h"
// stuff for SHA512
#include "sha2.h"
#include "blockwise.h"
#include APP_CONFIG
#include "log.h"
#if defined(STM32L432xx)
#include "salty.h"
#else
#include <sodium/crypto_sign_ed25519.h>
#endif
typedef enum
{
MBEDTLS_ECP_DP_NONE = 0,
MBEDTLS_ECP_DP_SECP192R1, /*!< 192-bits NIST curve */
MBEDTLS_ECP_DP_SECP224R1, /*!< 224-bits NIST curve */
MBEDTLS_ECP_DP_SECP256R1, /*!< 256-bits NIST curve */
MBEDTLS_ECP_DP_SECP384R1, /*!< 384-bits NIST curve */
MBEDTLS_ECP_DP_SECP521R1, /*!< 521-bits NIST curve */
MBEDTLS_ECP_DP_BP256R1, /*!< 256-bits Brainpool curve */
MBEDTLS_ECP_DP_BP384R1, /*!< 384-bits Brainpool curve */
MBEDTLS_ECP_DP_BP512R1, /*!< 512-bits Brainpool curve */
MBEDTLS_ECP_DP_CURVE25519, /*!< Curve25519 */
MBEDTLS_ECP_DP_SECP192K1, /*!< 192-bits "Koblitz" curve */
MBEDTLS_ECP_DP_SECP224K1, /*!< 224-bits "Koblitz" curve */
MBEDTLS_ECP_DP_SECP256K1, /*!< 256-bits "Koblitz" curve */
} mbedtls_ecp_group_id;
static SHA256_CTX sha256_ctx;
static cf_sha512_context sha512_ctx;
static const struct uECC_Curve_t * _es256_curve = NULL;
static const uint8_t * _signing_key = NULL;
static int _key_len = 0;
// Secrets for testing only
static uint8_t master_secret[64];
static uint8_t transport_secret[32];
void crypto_sha256_init(void)
{
sha256_init(&sha256_ctx);
}
void crypto_sha512_init(void)
{
cf_sha512_init(&sha512_ctx);
}
void crypto_load_master_secret(uint8_t * key)
{
#if KEY_SPACE_BYTES < 96
#error "need more key bytes"
#endif
memmove(master_secret, key, 64);
memmove(transport_secret, key+64, 32);
}
void crypto_reset_master_secret(void)
{
memset(master_secret, 0, 64);
memset(transport_secret, 0, 32);
ctap_generate_rng(master_secret, 64);
ctap_generate_rng(transport_secret, 32);
}
void crypto_sha256_update(uint8_t * data, size_t len)
{
sha256_update(&sha256_ctx, data, len);
}
void crypto_sha512_update(const uint8_t * data, size_t len) {
cf_sha512_update(&sha512_ctx, data, len);
}
void crypto_sha256_update_secret()
{
sha256_update(&sha256_ctx, master_secret, 32);
}
void crypto_sha256_final(uint8_t * hash)
{
sha256_final(&sha256_ctx, hash);
}
void crypto_sha512_final(uint8_t * hash)
{
// NB: there is also cf_sha512_digest
cf_sha512_digest_final(&sha512_ctx, hash);
}
void crypto_sha256_hmac_init(uint8_t * key, uint32_t klen, uint8_t * hmac)
{
uint8_t buf[64];
unsigned int i;
memset(buf, 0, sizeof(buf));
if (key == CRYPTO_MASTER_KEY)
{
key = master_secret;
klen = sizeof(master_secret)/2;
}
else if (key == CRYPTO_TRANSPORT_KEY)
{
key = transport_secret;
klen = 32;
}
if(klen > 64)
{
printf2(TAG_ERR, "Error, key size must be <= 64\n");
exit(1);
}
memmove(buf, key, klen);
for (i = 0; i < sizeof(buf); i++)
{
buf[i] = buf[i] ^ 0x36;
}
crypto_sha256_init();
crypto_sha256_update(buf, 64);
}
void crypto_sha256_hmac_final(uint8_t * key, uint32_t klen, uint8_t * hmac)
{
uint8_t buf[64];
unsigned int i;
crypto_sha256_final(hmac);
memset(buf, 0, sizeof(buf));
if (key == CRYPTO_MASTER_KEY)
{
key = master_secret;
klen = sizeof(master_secret)/2;
}
else if (key == CRYPTO_TRANSPORT_KEY2)
{
key = transport_secret;
klen = 32;
}
if(klen > 64)
{
printf2(TAG_ERR, "Error, key size must be <= 64\n");
exit(1);
}
memmove(buf, key, klen);
for (i = 0; i < sizeof(buf); i++)
{
buf[i] = buf[i] ^ 0x5c;
}
crypto_sha256_init();
crypto_sha256_update(buf, 64);
crypto_sha256_update(hmac, 32);
crypto_sha256_final(hmac);
}
void crypto_ecc256_init(void)
{
uECC_set_rng((uECC_RNG_Function)ctap_generate_rng);
_es256_curve = uECC_secp256r1();
}
void crypto_ecc256_load_attestation_key(void)
{
_signing_key = device_get_attestation_key();
_key_len = 32;
}
void crypto_ecc256_sign(uint8_t * data, int len, uint8_t * sig)
{
if ( uECC_sign(_signing_key, data, len, sig, _es256_curve) == 0)
{
printf2(TAG_ERR, "error, uECC failed\n");
exit(1);
}
}
void crypto_ecc256_load_key(uint8_t * data, int len, uint8_t * data2, int len2)
{
static uint8_t privkey[32];
generate_private_key(data,len,data2,len2,privkey);
_signing_key = privkey;
_key_len = 32;
}
void crypto_ecdsa_sign(uint8_t * data, int len, uint8_t * sig, int MBEDTLS_ECP_ID)
{
const struct uECC_Curve_t * curve = NULL;
switch(MBEDTLS_ECP_ID)
{
case MBEDTLS_ECP_DP_SECP192R1:
curve = uECC_secp192r1();
if (_key_len != 24) goto fail;
break;
case MBEDTLS_ECP_DP_SECP224R1:
curve = uECC_secp224r1();
if (_key_len != 28) goto fail;
break;
case MBEDTLS_ECP_DP_SECP256R1:
curve = uECC_secp256r1();
if (_key_len != 32) goto fail;
break;
case MBEDTLS_ECP_DP_SECP256K1:
curve = uECC_secp256k1();
if (_key_len != 32) goto fail;
break;
default:
printf2(TAG_ERR, "error, invalid ECDSA alg specifier\n");
exit(1);
}
if ( uECC_sign(_signing_key, data, len, sig, curve) == 0)
{
printf2(TAG_ERR, "error, uECC failed\n");
exit(1);
}
return;
fail:
printf2(TAG_ERR, "error, invalid key length\n");
exit(1);
}
void generate_private_key(uint8_t * data, int len, uint8_t * data2, int len2, uint8_t * privkey)
{
crypto_sha256_hmac_init(CRYPTO_MASTER_KEY, 0, privkey);
crypto_sha256_update(data, len);
crypto_sha256_update(data2, len2);
crypto_sha256_update(master_secret, 32); // TODO AES
crypto_sha256_hmac_final(CRYPTO_MASTER_KEY, 0, privkey);
crypto_aes256_init(master_secret + 32, NULL);
crypto_aes256_encrypt(privkey, 32);
}
/*int uECC_compute_public_key(const uint8_t *private_key, uint8_t *public_key, uECC_Curve curve);*/
void crypto_ecc256_derive_public_key(uint8_t * data, int len, uint8_t * x, uint8_t * y)
{
uint8_t privkey[32];
uint8_t pubkey[64];
generate_private_key(data,len,NULL,0,privkey);
memset(pubkey,0,sizeof(pubkey));
uECC_compute_public_key(privkey, pubkey, _es256_curve);
memmove(x,pubkey,32);
memmove(y,pubkey+32,32);
}
void crypto_ecc256_compute_public_key(uint8_t * privkey, uint8_t * pubkey)
{
uECC_compute_public_key(privkey, pubkey, _es256_curve);
}
void crypto_load_external_key(uint8_t * key, int len)
{
_signing_key = key;
_key_len = len;
}
void crypto_ecc256_make_key_pair(uint8_t * pubkey, uint8_t * privkey)
{
if (uECC_make_key(pubkey, privkey, _es256_curve) != 1)
{
printf2(TAG_ERR, "Error, uECC_make_key failed\n");
exit(1);
}
}
void crypto_ecc256_shared_secret(const uint8_t * pubkey, const uint8_t * privkey, uint8_t * shared_secret)
{
if (uECC_shared_secret(pubkey, privkey, shared_secret, _es256_curve) != 1)
{
printf2(TAG_ERR, "Error, uECC_shared_secret failed\n");
exit(1);
}
}
struct AES_ctx aes_ctx;
void crypto_aes256_init(uint8_t * key, uint8_t * nonce)
{
if (key == CRYPTO_TRANSPORT_KEY)
{
AES_init_ctx(&aes_ctx, transport_secret);
}
else
{
AES_init_ctx(&aes_ctx, key);
}
if (nonce == NULL)
{
memset(aes_ctx.Iv, 0, 16);
}
else
{
memmove(aes_ctx.Iv, nonce, 16);
}
}
// prevent round key recomputation
void crypto_aes256_reset_iv(uint8_t * nonce)
{
if (nonce == NULL)
{
memset(aes_ctx.Iv, 0, 16);
}
else
{
memmove(aes_ctx.Iv, nonce, 16);
}
}
void crypto_aes256_decrypt(uint8_t * buf, int length)
{
AES_CBC_decrypt_buffer(&aes_ctx, buf, length);
}
void crypto_aes256_encrypt(uint8_t * buf, int length)
{
AES_CBC_encrypt_buffer(&aes_ctx, buf, length);
}
void crypto_ed25519_derive_public_key(uint8_t * data, int len, uint8_t * x)
{
#if defined(STM32L432xx)
uint8_t seed[salty_SECRETKEY_SEED_LENGTH];
generate_private_key(data, len, NULL, 0, seed);
salty_public_key(seed, x);
#else
uint8_t seed[crypto_sign_ed25519_SEEDBYTES];
uint8_t sk[crypto_sign_ed25519_SECRETKEYBYTES];
generate_private_key(data, len, NULL, 0, seed);
crypto_sign_ed25519_seed_keypair(x, sk, seed);
#endif
}
void crypto_ed25519_load_key(uint8_t * data, int len)
{
#if defined(STM32L432xx)
static uint8_t seed[salty_SECRETKEY_SEED_LENGTH];
generate_private_key(data, len, NULL, 0, seed);
_signing_key = seed;
_key_len = salty_SECRETKEY_SEED_LENGTH;
#else
uint8_t seed[crypto_sign_ed25519_SEEDBYTES];
uint8_t pk[crypto_sign_ed25519_PUBLICKEYBYTES];
static uint8_t sk[crypto_sign_ed25519_SECRETKEYBYTES];
generate_private_key(data, len, NULL, 0, seed);
crypto_sign_ed25519_seed_keypair(pk, sk, seed);
_signing_key = sk;
_key_len = crypto_sign_ed25519_SECRETKEYBYTES;
#endif
}
void crypto_ed25519_sign(uint8_t * data, int len, uint8_t * sig)
{
#if defined(STM32L432xx)
// TODO: check that correct load_key() had been called?
salty_sign(_signing_key, data, len, sig);
#else
// TODO: check that correct load_key() had been called?
crypto_sign_ed25519_detached(sig, NULL, data, len, _signing_key);
#endif
}
#endif