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esp-idf/components/mbedtls/port/ecdsa/ecdsa_alt.c
Aditya Patwardhan 11128b73f5 feat(hal): Add countermeasure for ECDSA generate signature 
The ECDSA peripheral before ECO5 of esp32h2 does not perform the ECDSA
    sign operation in constant time. This allows an attacker to read the
    power signature of the ECDSA sign operation and then calculate the
    ECDSA key stored inside the eFuse. The commit adds a countermeasure
    for this attack. In this case the real ECDSA sign operation is
    masked under dummy ECDSA sign operations to hide its real power
    signature
2024-09-23 18:55:43 +08:00

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31 KiB
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/*
* SPDX-FileCopyrightText: 2023-2024 Espressif Systems (Shanghai) CO LTD
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <string.h>
#include "hal/ecc_ll.h"
#include "hal/ecdsa_ll.h"
#include "hal/ecdsa_hal.h"
#ifdef SOC_MPI_SUPPORTED
#include "hal/mpi_ll.h"
#endif
#include "esp_crypto_lock.h"
#include "esp_efuse.h"
#include "esp_private/esp_crypto_lock_internal.h"
#include "mbedtls/error.h"
#include "mbedtls/ecdsa.h"
#include "mbedtls/asn1.h"
#include "mbedtls/asn1write.h"
#include "mbedtls/platform_util.h"
#include "ecdsa/ecdsa_alt.h"
#include "soc/soc_caps.h"
#define ECDSA_KEY_MAGIC (short) 0xECD5A
#define ECDSA_SHA_LEN 32
#define MAX_ECDSA_COMPONENT_LEN 32
#if CONFIG_MBEDTLS_HARDWARE_ECDSA_SIGN_CONSTANT_TIME_CM
#include "esp_timer.h"
#if CONFIG_ESP_CRYPTO_DPA_PROTECTION_LEVEL_HIGH
/*
* This is the maximum time (in us) required for performing 1 ECDSA signature
* in this configuration along some additional margin considerations
*/
#define ECDSA_MAX_SIG_TIME 24000
#else /* CONFIG_ESP_CRYPTO_DPA_PROTECTION_LEVEL_HIGH */
#define ECDSA_MAX_SIG_TIME 17500
#endif /* !CONFIG_ESP_CRYPTO_DPA_PROTECTION_LEVEL_HIGH */
#if CONFIG_MBEDTLS_HARDWARE_ECDSA_SIGN_MASKING_CM
#define DUMMY_OP_COUNT ECDSA_SIGN_MAX_DUMMY_OP_COUNT
#else /* CONFIG_MBEDTLS_HARDWARE_ECDSA_SIGN_MASKING_CM */
#define DUMMY_OP_COUNT 0
#endif /* !CONFIG_MBEDTLS_HARDWARE_ECDSA_SIGN_MASKING_CM */
#define ECDSA_CM_FIXED_SIG_TIME ECDSA_MAX_SIG_TIME * (DUMMY_OP_COUNT + 1)
#endif /* CONFIG_MBEDTLS_HARDWARE_ECDSA_SIGN_CONSTANT_TIME_CM */
__attribute__((unused)) static const char *TAG = "ecdsa_alt";
static void esp_ecdsa_acquire_hardware(void)
{
esp_crypto_ecdsa_lock_acquire();
ECDSA_RCC_ATOMIC() {
ecdsa_ll_enable_bus_clock(true);
ecdsa_ll_reset_register();
}
ECC_RCC_ATOMIC() {
ecc_ll_enable_bus_clock(true);
ecc_ll_power_up();
ecc_ll_reset_register();
}
#ifdef SOC_ECDSA_USES_MPI
/* We need to reset the MPI peripheral because ECDSA peripheral
* of some targets use the MPI peripheral as well.
*/
MPI_RCC_ATOMIC() {
mpi_ll_enable_bus_clock(true);
mpi_ll_reset_register();
}
#endif /* SOC_ECDSA_USES_MPI */
}
static void esp_ecdsa_release_hardware(void)
{
ECDSA_RCC_ATOMIC() {
ecdsa_ll_enable_bus_clock(false);
}
ECC_RCC_ATOMIC() {
ecc_ll_enable_bus_clock(false);
ecc_ll_power_down();
}
#ifdef SOC_ECDSA_USES_MPI
MPI_RCC_ATOMIC() {
mpi_ll_enable_bus_clock(false);
}
#endif /* SOC_ECDSA_USES_MPI */
esp_crypto_ecdsa_lock_release();
}
static void ecdsa_be_to_le(const uint8_t* be_point, uint8_t *le_point, uint8_t len)
{
/* When the size is 24 bytes, it should be padded with 0 bytes*/
memset(le_point, 0x0, 32);
for(int i = 0; i < len; i++) {
le_point[i] = be_point[len - i - 1];
}
}
#ifdef SOC_ECDSA_SUPPORT_EXPORT_PUBKEY
int esp_ecdsa_load_pubkey(mbedtls_ecp_keypair *keypair, int efuse_blk)
{
int ret = -1;
bool use_km_key = (efuse_blk == USE_ECDSA_KEY_FROM_KEY_MANAGER)? true: false;
if (!use_km_key) {
if (efuse_blk < EFUSE_BLK_KEY0 || efuse_blk >= EFUSE_BLK_KEY_MAX) {
ESP_LOGE(TAG, "Invalid efuse block selected");
return ret;
}
}
ecdsa_curve_t curve;
esp_efuse_block_t blk;
uint16_t len;
uint8_t zeroes[MAX_ECDSA_COMPONENT_LEN] = {0};
uint8_t qx_le[MAX_ECDSA_COMPONENT_LEN];
uint8_t qy_le[MAX_ECDSA_COMPONENT_LEN];
if (keypair->MBEDTLS_PRIVATE(grp).id == MBEDTLS_ECP_DP_SECP192R1) {
curve = ECDSA_CURVE_SECP192R1;
len = 24;
} else if (keypair->MBEDTLS_PRIVATE(grp).id == MBEDTLS_ECP_DP_SECP256R1) {
curve = ECDSA_CURVE_SECP256R1;
len = 32;
} else {
return MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
}
if (!use_km_key) {
if (!esp_efuse_find_purpose(ESP_EFUSE_KEY_PURPOSE_ECDSA_KEY, &blk)) {
ESP_LOGE(TAG, "No efuse block with purpose ECDSA_KEY found");
return MBEDTLS_ERR_ECP_INVALID_KEY;
}
}
ecdsa_hal_config_t conf = {
.mode = ECDSA_MODE_EXPORT_PUBKEY,
.curve = curve,
};
if (use_km_key) {
conf.use_km_key = 1;
conf.efuse_key_blk = -1;
} else {
conf.use_km_key = 0;
conf.efuse_key_blk = efuse_blk;
}
esp_ecdsa_acquire_hardware();
bool process_again = false;
do {
ecdsa_hal_export_pubkey(&conf, qx_le, qy_le, len);
process_again = !ecdsa_hal_get_operation_result()
|| !memcmp(qx_le, zeroes, len)
|| !memcmp(qy_le, zeroes, len);
} while (process_again);
esp_ecdsa_release_hardware();
MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary_le(&(keypair->MBEDTLS_PRIVATE(Q).MBEDTLS_PRIVATE(X)), qx_le, len));
MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary_le(&(keypair->MBEDTLS_PRIVATE(Q).MBEDTLS_PRIVATE(Y)), qy_le, len));
MBEDTLS_MPI_CHK(mbedtls_mpi_lset(&(keypair->MBEDTLS_PRIVATE(Q).MBEDTLS_PRIVATE(Z)), 1));
return 0;
cleanup:
return MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
}
#endif /* SOC_ECDSA_SUPPORT_EXPORT_PUBKEY */
#ifdef CONFIG_MBEDTLS_HARDWARE_ECDSA_SIGN
int esp_ecdsa_privkey_load_mpi(mbedtls_mpi *key, int efuse_blk)
{
if (!key) {
ESP_LOGE(TAG, "Invalid memory");
return -1;
}
bool use_km_key = (efuse_blk == USE_ECDSA_KEY_FROM_KEY_MANAGER)? true: false;
if (!use_km_key) {
if (efuse_blk < EFUSE_BLK_KEY0 || efuse_blk >= EFUSE_BLK_KEY_MAX) {
ESP_LOGE(TAG, "Invalid efuse block");
return -1;
}
}
mbedtls_mpi_init(key);
/* We use the mbedtls_mpi struct to pass our own context to hardware ECDSA peripheral
* MPI struct expects `s` to be either 1 or -1, by setting it to 0xECD5A, we ensure that it does
* not collide with a valid MPI. This is done to differentiate between using the private key stored in efuse
* or using the private key provided by software
*
* `n` is used to store the efuse block which should be used as key
*/
key->MBEDTLS_PRIVATE(s) = ECDSA_KEY_MAGIC;
if (!use_km_key) {
key->MBEDTLS_PRIVATE(n) = efuse_blk;
} else {
key->MBEDTLS_PRIVATE(n) = (unsigned short) USE_ECDSA_KEY_FROM_KEY_MANAGER;
}
key->MBEDTLS_PRIVATE(p) = NULL;
return 0;
}
int esp_ecdsa_privkey_load_pk_context(mbedtls_pk_context *key_ctx, int efuse_blk)
{
const mbedtls_pk_info_t *pk_info;
mbedtls_ecp_keypair *keypair;
if (!key_ctx) {
ESP_LOGE(TAG, "Invalid memory");
return -1;
}
bool use_km_key = (efuse_blk == USE_ECDSA_KEY_FROM_KEY_MANAGER)? true: false;
if (!use_km_key) {
if (efuse_blk < EFUSE_BLK_KEY0 || efuse_blk >= EFUSE_BLK_KEY_MAX) {
ESP_LOGE(TAG, "Invalid efuse block");
return -1;
}
}
mbedtls_pk_init(key_ctx);
pk_info = mbedtls_pk_info_from_type(MBEDTLS_PK_ECDSA);
mbedtls_pk_setup(key_ctx, pk_info);
keypair = mbedtls_pk_ec(*key_ctx);
return esp_ecdsa_privkey_load_mpi(&(keypair->MBEDTLS_PRIVATE(d)), efuse_blk);
}
int esp_ecdsa_set_pk_context(mbedtls_pk_context *key_ctx, esp_ecdsa_pk_conf_t *conf)
{
int ret = -1;
int efuse_key_block = -1;
if (conf->use_km_key) {
efuse_key_block = USE_ECDSA_KEY_FROM_KEY_MANAGER;
} else {
efuse_key_block = conf->efuse_block;
}
if (!key_ctx) {
ESP_LOGE(TAG, "mbedtls_pk_context cannot be NULL");
return ret;
}
if (!conf) {
ESP_LOGE(TAG, "esp_ecdsa_pk_conf_t cannot be NULL");
return ret;
}
if (conf->grp_id != MBEDTLS_ECP_DP_SECP192R1 && conf->grp_id != MBEDTLS_ECP_DP_SECP256R1) {
ESP_LOGE(TAG, "Invalid EC curve group id mentioned in esp_ecdsa_pk_conf_t");
return ret;
}
if ((ret = esp_ecdsa_privkey_load_pk_context(key_ctx, efuse_key_block)) != 0) {
ESP_LOGE(TAG, "Loading private key context failed, esp_ecdsa_privkey_load_pk_context() returned %d", ret);
return ret;
}
mbedtls_ecp_keypair *keypair = mbedtls_pk_ec(*key_ctx);
if ((ret = mbedtls_ecp_group_load(&(keypair->MBEDTLS_PRIVATE(grp)), conf->grp_id)) != 0) {
ESP_LOGE(TAG, "Loading ecp group failed, mbedtls_pk_ec() returned %d", ret);
return ret;
}
#ifdef SOC_ECDSA_SUPPORT_EXPORT_PUBKEY
if (conf->load_pubkey) {
if ((ret = esp_ecdsa_load_pubkey(keypair, efuse_key_block)) != 0) {
ESP_LOGE(TAG, "Loading public key context failed, esp_ecdsa_load_pubkey() returned %d", ret);
return ret;
}
}
#endif
return 0;
}
static int esp_ecdsa_sign(mbedtls_ecp_group *grp, mbedtls_mpi* r, mbedtls_mpi* s,
const mbedtls_mpi *d, const unsigned char* msg, size_t msg_len,
ecdsa_sign_type_t k_type)
{
ecdsa_curve_t curve;
esp_efuse_block_t blk;
uint16_t len;
uint8_t zeroes[MAX_ECDSA_COMPONENT_LEN] = {0};
uint8_t sha_le[ECDSA_SHA_LEN];
uint8_t r_le[MAX_ECDSA_COMPONENT_LEN];
uint8_t s_le[MAX_ECDSA_COMPONENT_LEN];
if (!grp || !r || !s || !d || !msg) {
return MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
}
if (msg_len != ECDSA_SHA_LEN) {
return MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
}
if (grp->id == MBEDTLS_ECP_DP_SECP192R1) {
curve = ECDSA_CURVE_SECP192R1;
len = 24;
} else if (grp->id == MBEDTLS_ECP_DP_SECP256R1) {
curve = ECDSA_CURVE_SECP256R1;
len = 32;
} else {
return MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
}
bool use_km_key = false;
if (d->MBEDTLS_PRIVATE(n) == (unsigned short) USE_ECDSA_KEY_FROM_KEY_MANAGER) {
use_km_key = true;
}
if (!use_km_key) {
if (!esp_efuse_find_purpose(ESP_EFUSE_KEY_PURPOSE_ECDSA_KEY, &blk)) {
ESP_LOGE(TAG, "No efuse block with purpose ECDSA_KEY found");
return MBEDTLS_ERR_ECP_INVALID_KEY;
}
}
ecdsa_be_to_le(msg, sha_le, len);
esp_ecdsa_acquire_hardware();
bool process_again = false;
#ifdef SOC_ECDSA_SUPPORT_DETERMINISTIC_MODE
uint16_t deterministic_loop_number = 1;
#endif /* SOC_ECDSA_SUPPORT_DETERMINISTIC_MODE */
do {
ecdsa_hal_config_t conf = {
.mode = ECDSA_MODE_SIGN_GEN,
.curve = curve,
.sha_mode = ECDSA_Z_USER_PROVIDED,
.sign_type = k_type,
#ifdef SOC_ECDSA_SUPPORT_DETERMINISTIC_MODE
.loop_number = deterministic_loop_number++,
#endif /* SOC_ECDSA_SUPPORT_DETERMINISTIC_MODE */
};
if (use_km_key) {
conf.use_km_key = 1;
conf.efuse_key_blk = -1;
} else {
conf.use_km_key = 0;
conf.efuse_key_blk = d->MBEDTLS_PRIVATE(n);
}
#if CONFIG_MBEDTLS_HARDWARE_ECDSA_SIGN_CONSTANT_TIME_CM
uint64_t sig_time = esp_timer_get_time();
#endif
ecdsa_hal_gen_signature(&conf, sha_le, r_le, s_le, len);
#if CONFIG_MBEDTLS_HARDWARE_ECDSA_SIGN_CONSTANT_TIME_CM
sig_time = esp_timer_get_time() - sig_time;
if (sig_time < ECDSA_CM_FIXED_SIG_TIME) {
esp_rom_delay_us(ECDSA_CM_FIXED_SIG_TIME - sig_time);
}
#endif
process_again = !ecdsa_hal_get_operation_result()
|| !memcmp(r_le, zeroes, len)
|| !memcmp(s_le, zeroes, len);
#ifdef SOC_ECDSA_SUPPORT_DETERMINISTIC_MODE
if (k_type == ECDSA_K_TYPE_DETERMINISITIC) {
process_again |= !ecdsa_hal_det_signature_k_check();
}
#endif /* SOC_ECDSA_SUPPORT_DETERMINISTIC_MODE */
} while (process_again);
esp_ecdsa_release_hardware();
mbedtls_mpi_read_binary_le(r, r_le, len);
mbedtls_mpi_read_binary_le(s, s_le, len);
return 0;
}
/*
* Compute ECDSA signature of a hashed message;
*/
extern int __real_mbedtls_ecdsa_sign(mbedtls_ecp_group *grp, mbedtls_mpi *r, mbedtls_mpi *s,
const mbedtls_mpi *d, const unsigned char *buf, size_t blen,
int (*f_rng)(void *, unsigned char *, size_t), void *p_rng);
int __wrap_mbedtls_ecdsa_sign(mbedtls_ecp_group *grp, mbedtls_mpi *r, mbedtls_mpi *s,
const mbedtls_mpi *d, const unsigned char *buf, size_t blen,
int (*f_rng)(void *, unsigned char *, size_t), void *p_rng);
int __wrap_mbedtls_ecdsa_sign(mbedtls_ecp_group *grp, mbedtls_mpi *r, mbedtls_mpi *s,
const mbedtls_mpi *d, const unsigned char *buf, size_t blen,
int (*f_rng)(void *, unsigned char *, size_t), void *p_rng)
{
/*
* Check `d` whether it contains the hardware key
*/
if (d->MBEDTLS_PRIVATE(s) == ECDSA_KEY_MAGIC) {
// Use hardware ECDSA peripheral
return esp_ecdsa_sign(grp, r, s, d, buf, blen, ECDSA_K_TYPE_TRNG);
} else {
return __real_mbedtls_ecdsa_sign(grp, r, s, d, buf, blen, f_rng, p_rng);
}
}
extern int __real_mbedtls_ecdsa_sign_restartable(mbedtls_ecp_group *grp, mbedtls_mpi *r, mbedtls_mpi *s,
const mbedtls_mpi *d, const unsigned char *buf, size_t blen,
int (*f_rng)(void *, unsigned char *, size_t), void *p_rng,
int (*f_rng_blind)(void *, unsigned char *, size_t), void *p_rng_blind,
mbedtls_ecdsa_restart_ctx *rs_ctx);
int __wrap_mbedtls_ecdsa_sign_restartable(mbedtls_ecp_group *grp, mbedtls_mpi *r, mbedtls_mpi *s,
const mbedtls_mpi *d, const unsigned char *buf, size_t blen,
int (*f_rng)(void *, unsigned char *, size_t), void *p_rng,
int (*f_rng_blind)(void *, unsigned char *, size_t), void *p_rng_blind,
mbedtls_ecdsa_restart_ctx *rs_ctx);
int __wrap_mbedtls_ecdsa_sign_restartable(mbedtls_ecp_group *grp, mbedtls_mpi *r, mbedtls_mpi *s,
const mbedtls_mpi *d, const unsigned char *buf, size_t blen,
int (*f_rng)(void *, unsigned char *, size_t), void *p_rng,
int (*f_rng_blind)(void *, unsigned char *, size_t), void *p_rng_blind,
mbedtls_ecdsa_restart_ctx *rs_ctx)
{
/*
* Check `d` whether it contains the hardware key
*/
if (d->MBEDTLS_PRIVATE(s) == ECDSA_KEY_MAGIC) {
// Use hardware ECDSA peripheral
return esp_ecdsa_sign(grp, r, s, d, buf, blen, ECDSA_K_TYPE_TRNG);
} else {
return __real_mbedtls_ecdsa_sign_restartable(grp, r, s, d, buf, blen, f_rng, p_rng, f_rng_blind, p_rng_blind, rs_ctx);
}
}
#ifdef SOC_ECDSA_SUPPORT_DETERMINISTIC_MODE
extern int __real_mbedtls_ecdsa_sign_det_ext(mbedtls_ecp_group *grp, mbedtls_mpi *r,
mbedtls_mpi *s, const mbedtls_mpi *d,
const unsigned char *buf, size_t blen,
mbedtls_md_type_t md_alg,
int (*f_rng_blind)(void *, unsigned char *, size_t),
void *p_rng_blind);
int __wrap_mbedtls_ecdsa_sign_det_ext(mbedtls_ecp_group *grp, mbedtls_mpi *r,
mbedtls_mpi *s, const mbedtls_mpi *d,
const unsigned char *buf, size_t blen,
mbedtls_md_type_t md_alg,
int (*f_rng_blind)(void *, unsigned char *, size_t),
void *p_rng_blind);
int __wrap_mbedtls_ecdsa_sign_det_ext(mbedtls_ecp_group *grp, mbedtls_mpi *r,
mbedtls_mpi *s, const mbedtls_mpi *d,
const unsigned char *buf, size_t blen,
mbedtls_md_type_t md_alg,
int (*f_rng_blind)(void *, unsigned char *, size_t),
void *p_rng_blind)
{
/*
* Check `d` whether it contains the hardware key
*/
if (d->MBEDTLS_PRIVATE(s) == ECDSA_KEY_MAGIC) {
// Use hardware ECDSA peripheral
return esp_ecdsa_sign(grp, r, s, d, buf, blen, ECDSA_K_TYPE_DETERMINISITIC);
} else {
return __real_mbedtls_ecdsa_sign_det_ext(grp, r, s, d, buf, blen, md_alg, f_rng_blind, p_rng_blind);
}
}
extern int __real_mbedtls_ecdsa_sign_det_restartable(mbedtls_ecp_group *grp,
mbedtls_mpi *r, mbedtls_mpi *s,
const mbedtls_mpi *d, const unsigned char *buf, size_t blen,
mbedtls_md_type_t md_alg,
int (*f_rng_blind)(void *, unsigned char *, size_t),
void *p_rng_blind,
mbedtls_ecdsa_restart_ctx *rs_ctx);
int __wrap_mbedtls_ecdsa_sign_det_restartable(mbedtls_ecp_group *grp,
mbedtls_mpi *r, mbedtls_mpi *s,
const mbedtls_mpi *d, const unsigned char *buf, size_t blen,
mbedtls_md_type_t md_alg,
int (*f_rng_blind)(void *, unsigned char *, size_t),
void *p_rng_blind,
mbedtls_ecdsa_restart_ctx *rs_ctx);
int __wrap_mbedtls_ecdsa_sign_det_restartable(mbedtls_ecp_group *grp,
mbedtls_mpi *r, mbedtls_mpi *s,
const mbedtls_mpi *d, const unsigned char *buf, size_t blen,
mbedtls_md_type_t md_alg,
int (*f_rng_blind)(void *, unsigned char *, size_t),
void *p_rng_blind,
mbedtls_ecdsa_restart_ctx *rs_ctx)
{
/*
* Check `d` whether it contains the hardware key
*/
if (d->MBEDTLS_PRIVATE(s) == ECDSA_KEY_MAGIC) {
// Use hardware ECDSA peripheral
return esp_ecdsa_sign(grp, r, s, d, buf, blen, ECDSA_K_TYPE_DETERMINISITIC);
} else {
return __real_mbedtls_ecdsa_sign_det_restartable(grp, r, s, d, buf, blen, md_alg, f_rng_blind, p_rng_blind, NULL);
}
}
#endif /* SOC_ECDSA_SUPPORT_DETERMINISTIC_MODE */
int __real_mbedtls_ecdsa_write_signature_restartable(mbedtls_ecdsa_context *ctx,
mbedtls_md_type_t md_alg,
const unsigned char *hash, size_t hlen,
unsigned char *sig, size_t sig_size, size_t *slen,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng,
mbedtls_ecdsa_restart_ctx *rs_ctx);
int __wrap_mbedtls_ecdsa_write_signature_restartable(mbedtls_ecdsa_context *ctx,
mbedtls_md_type_t md_alg,
const unsigned char *hash, size_t hlen,
unsigned char *sig, size_t sig_size, size_t *slen,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng,
mbedtls_ecdsa_restart_ctx *rs_ctx);
/*
* Convert a signature (given by context) to ASN.1
*/
static int ecdsa_signature_to_asn1(const mbedtls_mpi *r, const mbedtls_mpi *s,
unsigned char *sig, size_t sig_size,
size_t *slen)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
unsigned char buf[MBEDTLS_ECDSA_MAX_LEN] = { 0 };
// Setting the pointer p to the end of the buffer as the functions used afterwards write in backwards manner in the given buffer.
unsigned char *p = buf + sizeof(buf);
size_t len = 0;
MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_mpi(&p, buf, s));
MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_mpi(&p, buf, r));
MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(&p, buf, len));
MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(&p, buf,
MBEDTLS_ASN1_CONSTRUCTED |
MBEDTLS_ASN1_SEQUENCE));
if (len > sig_size) {
return MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL;
}
memcpy(sig, p, len);
*slen = len;
return 0;
}
int __wrap_mbedtls_ecdsa_write_signature_restartable(mbedtls_ecdsa_context *ctx,
mbedtls_md_type_t md_alg,
const unsigned char *hash, size_t hlen,
unsigned char *sig, size_t sig_size, size_t *slen,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng,
mbedtls_ecdsa_restart_ctx *rs_ctx)
{
if (ctx->MBEDTLS_PRIVATE(d).MBEDTLS_PRIVATE(s) != ECDSA_KEY_MAGIC) {
return __real_mbedtls_ecdsa_write_signature_restartable(ctx, md_alg, hash, hlen, sig, sig_size, slen, f_rng, p_rng, rs_ctx);
}
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
mbedtls_mpi r, s;
mbedtls_mpi_init(&r);
mbedtls_mpi_init(&s);
/*
* Check `d` whether it contains the hardware key
*/
if (ctx->MBEDTLS_PRIVATE(d).MBEDTLS_PRIVATE(s) == ECDSA_KEY_MAGIC) {
// Use hardware ECDSA peripheral
#if defined(SOC_ECDSA_SUPPORT_DETERMINISTIC_MODE) && defined(CONFIG_MBEDTLS_ECDSA_DETERMINISTIC)
MBEDTLS_MPI_CHK(esp_ecdsa_sign(&ctx->MBEDTLS_PRIVATE(grp), &r, &s, &ctx->MBEDTLS_PRIVATE(d), hash, hlen, ECDSA_K_TYPE_DETERMINISITIC));
#else
MBEDTLS_MPI_CHK(esp_ecdsa_sign(&ctx->MBEDTLS_PRIVATE(grp), &r, &s, &ctx->MBEDTLS_PRIVATE(d), hash, hlen, ECDSA_K_TYPE_TRNG));
#endif /* SOC_ECDSA_SUPPORT_DETERMINISTIC_MODE */
}
MBEDTLS_MPI_CHK(ecdsa_signature_to_asn1(&r, &s, sig, sig_size, slen));
cleanup:
mbedtls_mpi_free(&r);
mbedtls_mpi_free(&s);
return ret;
}
int __wrap_mbedtls_ecdsa_write_signature(mbedtls_ecdsa_context *ctx,
mbedtls_md_type_t md_alg,
const unsigned char *hash, size_t hlen,
unsigned char *sig, size_t sig_size, size_t *slen,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng);
int __wrap_mbedtls_ecdsa_write_signature(mbedtls_ecdsa_context *ctx,
mbedtls_md_type_t md_alg,
const unsigned char *hash, size_t hlen,
unsigned char *sig, size_t sig_size, size_t *slen,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng)
{
return __wrap_mbedtls_ecdsa_write_signature_restartable(
ctx, md_alg, hash, hlen, sig, sig_size, slen,
f_rng, p_rng, NULL);
}
#endif /* CONFIG_MBEDTLS_HARDWARE_ECDSA_SIGN */
#ifdef CONFIG_MBEDTLS_HARDWARE_ECDSA_VERIFY
static int esp_ecdsa_verify(mbedtls_ecp_group *grp,
const unsigned char *buf, size_t blen,
const mbedtls_ecp_point *Q,
const mbedtls_mpi *r,
const mbedtls_mpi *s)
{
ecdsa_curve_t curve;
uint16_t len;
uint8_t r_le[MAX_ECDSA_COMPONENT_LEN];
uint8_t s_le[MAX_ECDSA_COMPONENT_LEN];
uint8_t qx_le[MAX_ECDSA_COMPONENT_LEN];
uint8_t qy_le[MAX_ECDSA_COMPONENT_LEN];
uint8_t sha_le[ECDSA_SHA_LEN];
if (!grp || !buf || !Q || !r || !s) {
return MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
}
if (blen != ECDSA_SHA_LEN) {
return MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
}
if (grp->id == MBEDTLS_ECP_DP_SECP192R1) {
curve = ECDSA_CURVE_SECP192R1;
len = 24;
} else if (grp->id == MBEDTLS_ECP_DP_SECP256R1) {
curve = ECDSA_CURVE_SECP256R1;
len = 32;
} else {
return MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
}
if (mbedtls_mpi_cmp_int(r, 1) < 0 || mbedtls_mpi_cmp_mpi(r, &grp->N) >= 0 ||
mbedtls_mpi_cmp_int(s, 1) < 0 || mbedtls_mpi_cmp_mpi(s, &grp->N) >= 0 )
{
return MBEDTLS_ERR_ECP_VERIFY_FAILED;
}
ecdsa_be_to_le(buf, sha_le, len);
mbedtls_mpi_write_binary_le(&Q->MBEDTLS_PRIVATE(X), qx_le, len);
mbedtls_mpi_write_binary_le(&Q->MBEDTLS_PRIVATE(Y), qy_le, len);
mbedtls_mpi_write_binary_le(r, r_le, len);
mbedtls_mpi_write_binary_le(s, s_le, len);
esp_ecdsa_acquire_hardware();
ecdsa_hal_config_t conf = {
.mode = ECDSA_MODE_SIGN_VERIFY,
.curve = curve,
.sha_mode = ECDSA_Z_USER_PROVIDED,
};
int ret = ecdsa_hal_verify_signature(&conf, sha_le, r_le, s_le, qx_le, qy_le, len);
esp_ecdsa_release_hardware();
if (ret != 0) {
return MBEDTLS_ERR_ECP_VERIFY_FAILED;
}
return ret;
}
/*
* Verify ECDSA signature of hashed message
*/
extern int __real_mbedtls_ecdsa_verify_restartable(mbedtls_ecp_group *grp,
const unsigned char *buf, size_t blen,
const mbedtls_ecp_point *Q,
const mbedtls_mpi *r,
const mbedtls_mpi *s,
mbedtls_ecdsa_restart_ctx *rs_ctx);
int __wrap_mbedtls_ecdsa_verify_restartable(mbedtls_ecp_group *grp,
const unsigned char *buf, size_t blen,
const mbedtls_ecp_point *Q,
const mbedtls_mpi *r,
const mbedtls_mpi *s,
mbedtls_ecdsa_restart_ctx *rs_ctx);
int __wrap_mbedtls_ecdsa_verify_restartable(mbedtls_ecp_group *grp,
const unsigned char *buf, size_t blen,
const mbedtls_ecp_point *Q,
const mbedtls_mpi *r,
const mbedtls_mpi *s,
mbedtls_ecdsa_restart_ctx *rs_ctx)
{
if ((grp->id == MBEDTLS_ECP_DP_SECP192R1 || grp->id == MBEDTLS_ECP_DP_SECP256R1) && blen == ECDSA_SHA_LEN) {
return esp_ecdsa_verify(grp, buf, blen, Q, r, s);
} else {
return __real_mbedtls_ecdsa_verify_restartable(grp, buf, blen, Q, r, s, rs_ctx);
}
}
/*
* Verify ECDSA signature of hashed message
*/
extern int __real_mbedtls_ecdsa_verify(mbedtls_ecp_group *grp,
const unsigned char *buf, size_t blen,
const mbedtls_ecp_point *Q,
const mbedtls_mpi *r,
const mbedtls_mpi *s);
int __wrap_mbedtls_ecdsa_verify(mbedtls_ecp_group *grp,
const unsigned char *buf, size_t blen,
const mbedtls_ecp_point *Q,
const mbedtls_mpi *r,
const mbedtls_mpi *s);
int __wrap_mbedtls_ecdsa_verify(mbedtls_ecp_group *grp,
const unsigned char *buf, size_t blen,
const mbedtls_ecp_point *Q,
const mbedtls_mpi *r,
const mbedtls_mpi *s)
{
return __wrap_mbedtls_ecdsa_verify_restartable(grp, buf, blen, Q, r, s, NULL);
}
int __real_mbedtls_ecdsa_read_signature_restartable(mbedtls_ecdsa_context *ctx,
const unsigned char *hash, size_t hlen,
const unsigned char *sig, size_t slen,
mbedtls_ecdsa_restart_ctx *rs_ctx);
int __wrap_mbedtls_ecdsa_read_signature_restartable(mbedtls_ecdsa_context *ctx,
const unsigned char *hash, size_t hlen,
const unsigned char *sig, size_t slen,
mbedtls_ecdsa_restart_ctx *rs_ctx);
int __wrap_mbedtls_ecdsa_read_signature_restartable(mbedtls_ecdsa_context *ctx,
const unsigned char *hash, size_t hlen,
const unsigned char *sig, size_t slen,
mbedtls_ecdsa_restart_ctx *rs_ctx)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
unsigned char *p = (unsigned char *) sig;
const unsigned char *end = sig + slen;
size_t len;
mbedtls_mpi r, s;
mbedtls_mpi_init(&r);
mbedtls_mpi_init(&s);
if ((ret = mbedtls_asn1_get_tag(&p, end, &len,
MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) {
ret += MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
goto cleanup;
}
if (p + len != end) {
ret = MBEDTLS_ERROR_ADD(MBEDTLS_ERR_ECP_BAD_INPUT_DATA,
MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
goto cleanup;
}
if ((ret = mbedtls_asn1_get_mpi(&p, end, &r)) != 0 ||
(ret = mbedtls_asn1_get_mpi(&p, end, &s)) != 0) {
ret += MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
goto cleanup;
}
if ((ret = __wrap_mbedtls_ecdsa_verify_restartable(&ctx->MBEDTLS_PRIVATE(grp), hash, hlen,
&ctx->MBEDTLS_PRIVATE(Q), &r, &s, NULL)) != 0) {
goto cleanup;
}
/* At this point we know that the buffer starts with a valid signature.
* Return 0 if the buffer just contains the signature, and a specific
* error code if the valid signature is followed by more data. */
if (p != end) {
ret = MBEDTLS_ERR_ECP_SIG_LEN_MISMATCH;
}
cleanup:
mbedtls_mpi_free(&r);
mbedtls_mpi_free(&s);
return ret;
}
int __real_mbedtls_ecdsa_read_signature(mbedtls_ecdsa_context *ctx,
const unsigned char *hash, size_t hlen,
const unsigned char *sig, size_t slen);
int __wrap_mbedtls_ecdsa_read_signature(mbedtls_ecdsa_context *ctx,
const unsigned char *hash, size_t hlen,
const unsigned char *sig, size_t slen);
int __wrap_mbedtls_ecdsa_read_signature(mbedtls_ecdsa_context *ctx,
const unsigned char *hash, size_t hlen,
const unsigned char *sig, size_t slen)
{
return __wrap_mbedtls_ecdsa_read_signature_restartable(
ctx, hash, hlen, sig, slen, NULL);
}
#endif /* CONFIG_MBEDTLS_HARDWARE_ECDSA_VERIFY */
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