gbe_fork/mbedtls/psa_crypto_mac.c
2023-12-24 14:33:40 +02:00

497 lines
15 KiB
C

/*
* PSA MAC layer on top of Mbed TLS software crypto
*/
/*
* Copyright The Mbed TLS Contributors
* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
*/
#include "common.h"
#if defined(MBEDTLS_PSA_CRYPTO_C)
#include <psa/crypto.h>
#include "psa_crypto_core.h"
#include "psa_crypto_cipher.h"
#include "psa_crypto_mac.h"
#include <mbedtls/md.h>
#include <mbedtls/error.h>
#include "mbedtls/constant_time.h"
#include <string.h>
#if defined(MBEDTLS_PSA_BUILTIN_ALG_HMAC)
static psa_status_t psa_hmac_abort_internal(
mbedtls_psa_hmac_operation_t *hmac)
{
mbedtls_platform_zeroize(hmac->opad, sizeof(hmac->opad));
return psa_hash_abort(&hmac->hash_ctx);
}
static psa_status_t psa_hmac_setup_internal(
mbedtls_psa_hmac_operation_t *hmac,
const uint8_t *key,
size_t key_length,
psa_algorithm_t hash_alg)
{
uint8_t ipad[PSA_HMAC_MAX_HASH_BLOCK_SIZE];
size_t i;
size_t hash_size = PSA_HASH_LENGTH(hash_alg);
size_t block_size = PSA_HASH_BLOCK_LENGTH(hash_alg);
psa_status_t status;
hmac->alg = hash_alg;
/* Sanity checks on block_size, to guarantee that there won't be a buffer
* overflow below. This should never trigger if the hash algorithm
* is implemented correctly. */
/* The size checks against the ipad and opad buffers cannot be written
* `block_size > sizeof( ipad ) || block_size > sizeof( hmac->opad )`
* because that triggers -Wlogical-op on GCC 7.3. */
if (block_size > sizeof(ipad)) {
return PSA_ERROR_NOT_SUPPORTED;
}
if (block_size > sizeof(hmac->opad)) {
return PSA_ERROR_NOT_SUPPORTED;
}
if (block_size < hash_size) {
return PSA_ERROR_NOT_SUPPORTED;
}
if (key_length > block_size) {
status = psa_hash_compute(hash_alg, key, key_length,
ipad, sizeof(ipad), &key_length);
if (status != PSA_SUCCESS) {
goto cleanup;
}
}
/* A 0-length key is not commonly used in HMAC when used as a MAC,
* but it is permitted. It is common when HMAC is used in HKDF, for
* example. Don't call `memcpy` in the 0-length because `key` could be
* an invalid pointer which would make the behavior undefined. */
else if (key_length != 0) {
memcpy(ipad, key, key_length);
}
/* ipad contains the key followed by garbage. Xor and fill with 0x36
* to create the ipad value. */
for (i = 0; i < key_length; i++) {
ipad[i] ^= 0x36;
}
memset(ipad + key_length, 0x36, block_size - key_length);
/* Copy the key material from ipad to opad, flipping the requisite bits,
* and filling the rest of opad with the requisite constant. */
for (i = 0; i < key_length; i++) {
hmac->opad[i] = ipad[i] ^ 0x36 ^ 0x5C;
}
memset(hmac->opad + key_length, 0x5C, block_size - key_length);
status = psa_hash_setup(&hmac->hash_ctx, hash_alg);
if (status != PSA_SUCCESS) {
goto cleanup;
}
status = psa_hash_update(&hmac->hash_ctx, ipad, block_size);
cleanup:
mbedtls_platform_zeroize(ipad, sizeof(ipad));
return status;
}
static psa_status_t psa_hmac_update_internal(
mbedtls_psa_hmac_operation_t *hmac,
const uint8_t *data,
size_t data_length)
{
return psa_hash_update(&hmac->hash_ctx, data, data_length);
}
static psa_status_t psa_hmac_finish_internal(
mbedtls_psa_hmac_operation_t *hmac,
uint8_t *mac,
size_t mac_size)
{
uint8_t tmp[PSA_HASH_MAX_SIZE];
psa_algorithm_t hash_alg = hmac->alg;
size_t hash_size = 0;
size_t block_size = PSA_HASH_BLOCK_LENGTH(hash_alg);
psa_status_t status;
status = psa_hash_finish(&hmac->hash_ctx, tmp, sizeof(tmp), &hash_size);
if (status != PSA_SUCCESS) {
return status;
}
/* From here on, tmp needs to be wiped. */
status = psa_hash_setup(&hmac->hash_ctx, hash_alg);
if (status != PSA_SUCCESS) {
goto exit;
}
status = psa_hash_update(&hmac->hash_ctx, hmac->opad, block_size);
if (status != PSA_SUCCESS) {
goto exit;
}
status = psa_hash_update(&hmac->hash_ctx, tmp, hash_size);
if (status != PSA_SUCCESS) {
goto exit;
}
status = psa_hash_finish(&hmac->hash_ctx, tmp, sizeof(tmp), &hash_size);
if (status != PSA_SUCCESS) {
goto exit;
}
memcpy(mac, tmp, mac_size);
exit:
mbedtls_platform_zeroize(tmp, hash_size);
return status;
}
#endif /* MBEDTLS_PSA_BUILTIN_ALG_HMAC */
#if defined(MBEDTLS_PSA_BUILTIN_ALG_CMAC)
static psa_status_t cmac_setup(mbedtls_psa_mac_operation_t *operation,
const psa_key_attributes_t *attributes,
const uint8_t *key_buffer)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
#if defined(PSA_WANT_KEY_TYPE_DES)
/* Mbed TLS CMAC does not accept 3DES with only two keys, nor does it accept
* to do CMAC with pure DES, so return NOT_SUPPORTED here. */
if (psa_get_key_type(attributes) == PSA_KEY_TYPE_DES &&
(psa_get_key_bits(attributes) == 64 ||
psa_get_key_bits(attributes) == 128)) {
return PSA_ERROR_NOT_SUPPORTED;
}
#endif
const mbedtls_cipher_info_t *cipher_info =
mbedtls_cipher_info_from_psa(
PSA_ALG_CMAC,
psa_get_key_type(attributes),
psa_get_key_bits(attributes),
NULL);
if (cipher_info == NULL) {
return PSA_ERROR_NOT_SUPPORTED;
}
ret = mbedtls_cipher_setup(&operation->ctx.cmac, cipher_info);
if (ret != 0) {
goto exit;
}
ret = mbedtls_cipher_cmac_starts(&operation->ctx.cmac,
key_buffer,
psa_get_key_bits(attributes));
exit:
return mbedtls_to_psa_error(ret);
}
#endif /* MBEDTLS_PSA_BUILTIN_ALG_CMAC */
#if defined(MBEDTLS_PSA_BUILTIN_ALG_HMAC) || \
defined(MBEDTLS_PSA_BUILTIN_ALG_CMAC)
/* Initialize this driver's MAC operation structure. Once this function has been
* called, mbedtls_psa_mac_abort can run and will do the right thing. */
static psa_status_t mac_init(
mbedtls_psa_mac_operation_t *operation,
psa_algorithm_t alg)
{
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
operation->alg = alg;
#if defined(MBEDTLS_PSA_BUILTIN_ALG_CMAC)
if (PSA_ALG_FULL_LENGTH_MAC(operation->alg) == PSA_ALG_CMAC) {
mbedtls_cipher_init(&operation->ctx.cmac);
status = PSA_SUCCESS;
} else
#endif /* MBEDTLS_PSA_BUILTIN_ALG_CMAC */
#if defined(MBEDTLS_PSA_BUILTIN_ALG_HMAC)
if (PSA_ALG_IS_HMAC(operation->alg)) {
/* We'll set up the hash operation later in psa_hmac_setup_internal. */
operation->ctx.hmac.alg = 0;
status = PSA_SUCCESS;
} else
#endif /* MBEDTLS_PSA_BUILTIN_ALG_HMAC */
{
(void) operation;
status = PSA_ERROR_NOT_SUPPORTED;
}
if (status != PSA_SUCCESS) {
memset(operation, 0, sizeof(*operation));
}
return status;
}
psa_status_t mbedtls_psa_mac_abort(mbedtls_psa_mac_operation_t *operation)
{
if (operation->alg == 0) {
/* The object has (apparently) been initialized but it is not
* in use. It's ok to call abort on such an object, and there's
* nothing to do. */
return PSA_SUCCESS;
} else
#if defined(MBEDTLS_PSA_BUILTIN_ALG_CMAC)
if (PSA_ALG_FULL_LENGTH_MAC(operation->alg) == PSA_ALG_CMAC) {
mbedtls_cipher_free(&operation->ctx.cmac);
} else
#endif /* MBEDTLS_PSA_BUILTIN_ALG_CMAC */
#if defined(MBEDTLS_PSA_BUILTIN_ALG_HMAC)
if (PSA_ALG_IS_HMAC(operation->alg)) {
psa_hmac_abort_internal(&operation->ctx.hmac);
} else
#endif /* MBEDTLS_PSA_BUILTIN_ALG_HMAC */
{
/* Sanity check (shouldn't happen: operation->alg should
* always have been initialized to a valid value). */
goto bad_state;
}
operation->alg = 0;
return PSA_SUCCESS;
bad_state:
/* If abort is called on an uninitialized object, we can't trust
* anything. Wipe the object in case it contains confidential data.
* This may result in a memory leak if a pointer gets overwritten,
* but it's too late to do anything about this. */
memset(operation, 0, sizeof(*operation));
return PSA_ERROR_BAD_STATE;
}
static psa_status_t psa_mac_setup(mbedtls_psa_mac_operation_t *operation,
const psa_key_attributes_t *attributes,
const uint8_t *key_buffer,
size_t key_buffer_size,
psa_algorithm_t alg)
{
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
/* A context must be freshly initialized before it can be set up. */
if (operation->alg != 0) {
return PSA_ERROR_BAD_STATE;
}
status = mac_init(operation, alg);
if (status != PSA_SUCCESS) {
return status;
}
#if defined(MBEDTLS_PSA_BUILTIN_ALG_CMAC)
if (PSA_ALG_FULL_LENGTH_MAC(alg) == PSA_ALG_CMAC) {
/* Key buffer size for CMAC is dictated by the key bits set on the
* attributes, and previously validated by the core on key import. */
(void) key_buffer_size;
status = cmac_setup(operation, attributes, key_buffer);
} else
#endif /* MBEDTLS_PSA_BUILTIN_ALG_CMAC */
#if defined(MBEDTLS_PSA_BUILTIN_ALG_HMAC)
if (PSA_ALG_IS_HMAC(alg)) {
status = psa_hmac_setup_internal(&operation->ctx.hmac,
key_buffer,
key_buffer_size,
PSA_ALG_HMAC_GET_HASH(alg));
} else
#endif /* MBEDTLS_PSA_BUILTIN_ALG_HMAC */
{
(void) attributes;
(void) key_buffer;
(void) key_buffer_size;
status = PSA_ERROR_NOT_SUPPORTED;
}
if (status != PSA_SUCCESS) {
mbedtls_psa_mac_abort(operation);
}
return status;
}
psa_status_t mbedtls_psa_mac_sign_setup(
mbedtls_psa_mac_operation_t *operation,
const psa_key_attributes_t *attributes,
const uint8_t *key_buffer,
size_t key_buffer_size,
psa_algorithm_t alg)
{
return psa_mac_setup(operation, attributes,
key_buffer, key_buffer_size, alg);
}
psa_status_t mbedtls_psa_mac_verify_setup(
mbedtls_psa_mac_operation_t *operation,
const psa_key_attributes_t *attributes,
const uint8_t *key_buffer,
size_t key_buffer_size,
psa_algorithm_t alg)
{
return psa_mac_setup(operation, attributes,
key_buffer, key_buffer_size, alg);
}
psa_status_t mbedtls_psa_mac_update(
mbedtls_psa_mac_operation_t *operation,
const uint8_t *input,
size_t input_length)
{
if (operation->alg == 0) {
return PSA_ERROR_BAD_STATE;
}
#if defined(MBEDTLS_PSA_BUILTIN_ALG_CMAC)
if (PSA_ALG_FULL_LENGTH_MAC(operation->alg) == PSA_ALG_CMAC) {
return mbedtls_to_psa_error(
mbedtls_cipher_cmac_update(&operation->ctx.cmac,
input, input_length));
} else
#endif /* MBEDTLS_PSA_BUILTIN_ALG_CMAC */
#if defined(MBEDTLS_PSA_BUILTIN_ALG_HMAC)
if (PSA_ALG_IS_HMAC(operation->alg)) {
return psa_hmac_update_internal(&operation->ctx.hmac,
input, input_length);
} else
#endif /* MBEDTLS_PSA_BUILTIN_ALG_HMAC */
{
/* This shouldn't happen if `operation` was initialized by
* a setup function. */
(void) input;
(void) input_length;
return PSA_ERROR_BAD_STATE;
}
}
static psa_status_t psa_mac_finish_internal(
mbedtls_psa_mac_operation_t *operation,
uint8_t *mac, size_t mac_size)
{
#if defined(MBEDTLS_PSA_BUILTIN_ALG_CMAC)
if (PSA_ALG_FULL_LENGTH_MAC(operation->alg) == PSA_ALG_CMAC) {
uint8_t tmp[PSA_BLOCK_CIPHER_BLOCK_MAX_SIZE];
int ret = mbedtls_cipher_cmac_finish(&operation->ctx.cmac, tmp);
if (ret == 0) {
memcpy(mac, tmp, mac_size);
}
mbedtls_platform_zeroize(tmp, sizeof(tmp));
return mbedtls_to_psa_error(ret);
} else
#endif /* MBEDTLS_PSA_BUILTIN_ALG_CMAC */
#if defined(MBEDTLS_PSA_BUILTIN_ALG_HMAC)
if (PSA_ALG_IS_HMAC(operation->alg)) {
return psa_hmac_finish_internal(&operation->ctx.hmac,
mac, mac_size);
} else
#endif /* MBEDTLS_PSA_BUILTIN_ALG_HMAC */
{
/* This shouldn't happen if `operation` was initialized by
* a setup function. */
(void) operation;
(void) mac;
(void) mac_size;
return PSA_ERROR_BAD_STATE;
}
}
psa_status_t mbedtls_psa_mac_sign_finish(
mbedtls_psa_mac_operation_t *operation,
uint8_t *mac,
size_t mac_size,
size_t *mac_length)
{
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
if (operation->alg == 0) {
return PSA_ERROR_BAD_STATE;
}
status = psa_mac_finish_internal(operation, mac, mac_size);
if (status == PSA_SUCCESS) {
*mac_length = mac_size;
}
return status;
}
psa_status_t mbedtls_psa_mac_verify_finish(
mbedtls_psa_mac_operation_t *operation,
const uint8_t *mac,
size_t mac_length)
{
uint8_t actual_mac[PSA_MAC_MAX_SIZE];
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
if (operation->alg == 0) {
return PSA_ERROR_BAD_STATE;
}
/* Consistency check: requested MAC length fits our local buffer */
if (mac_length > sizeof(actual_mac)) {
return PSA_ERROR_INVALID_ARGUMENT;
}
status = psa_mac_finish_internal(operation, actual_mac, mac_length);
if (status != PSA_SUCCESS) {
goto cleanup;
}
if (mbedtls_ct_memcmp(mac, actual_mac, mac_length) != 0) {
status = PSA_ERROR_INVALID_SIGNATURE;
}
cleanup:
mbedtls_platform_zeroize(actual_mac, sizeof(actual_mac));
return status;
}
psa_status_t mbedtls_psa_mac_compute(
const psa_key_attributes_t *attributes,
const uint8_t *key_buffer,
size_t key_buffer_size,
psa_algorithm_t alg,
const uint8_t *input,
size_t input_length,
uint8_t *mac,
size_t mac_size,
size_t *mac_length)
{
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
mbedtls_psa_mac_operation_t operation = MBEDTLS_PSA_MAC_OPERATION_INIT;
status = psa_mac_setup(&operation,
attributes, key_buffer, key_buffer_size,
alg);
if (status != PSA_SUCCESS) {
goto exit;
}
if (input_length > 0) {
status = mbedtls_psa_mac_update(&operation, input, input_length);
if (status != PSA_SUCCESS) {
goto exit;
}
}
status = psa_mac_finish_internal(&operation, mac, mac_size);
if (status == PSA_SUCCESS) {
*mac_length = mac_size;
}
exit:
mbedtls_psa_mac_abort(&operation);
return status;
}
#endif /* MBEDTLS_PSA_BUILTIN_ALG_HMAC || MBEDTLS_PSA_BUILTIN_ALG_CMAC */
#endif /* MBEDTLS_PSA_CRYPTO_C */