/*
* PSA PAKE 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_pake.h"
#include "psa_crypto_slot_management.h"
#include <mbedtls/ecjpake.h>
#include "psa_util_internal.h"
#include <mbedtls/platform.h>
#include <mbedtls/error.h>
#include <string.h>
/*
* State sequence:
*
* psa_pake_setup()
* |
* |-- In any order:
* | | psa_pake_set_password_key()
* | | psa_pake_set_user()
* | | psa_pake_set_peer()
* | | psa_pake_set_role()
* |
* |--- In any order: (First round input before or after first round output)
* | |
* | |------ In Order
* | | | psa_pake_output(PSA_PAKE_STEP_KEY_SHARE)
* | | | psa_pake_output(PSA_PAKE_STEP_ZK_PUBLIC)
* | | | psa_pake_output(PSA_PAKE_STEP_ZK_PROOF)
* | | | psa_pake_output(PSA_PAKE_STEP_KEY_SHARE)
* | | | psa_pake_output(PSA_PAKE_STEP_ZK_PUBLIC)
* | | | psa_pake_output(PSA_PAKE_STEP_ZK_PROOF)
* | |
* | |------ In Order:
* | | psa_pake_input(PSA_PAKE_STEP_KEY_SHARE)
* | | psa_pake_input(PSA_PAKE_STEP_ZK_PUBLIC)
* | | psa_pake_input(PSA_PAKE_STEP_ZK_PROOF)
* | | psa_pake_input(PSA_PAKE_STEP_KEY_SHARE)
* | | psa_pake_input(PSA_PAKE_STEP_ZK_PUBLIC)
* | | psa_pake_input(PSA_PAKE_STEP_ZK_PROOF)
* |
* |--- In any order: (Second round input before or after second round output)
* | |
* | |------ In Order
* | | | psa_pake_output(PSA_PAKE_STEP_KEY_SHARE)
* | | | psa_pake_output(PSA_PAKE_STEP_ZK_PUBLIC)
* | | | psa_pake_output(PSA_PAKE_STEP_ZK_PROOF)
* | |
* | |------ In Order:
* | | psa_pake_input(PSA_PAKE_STEP_KEY_SHARE)
* | | psa_pake_input(PSA_PAKE_STEP_ZK_PUBLIC)
* | | psa_pake_input(PSA_PAKE_STEP_ZK_PROOF)
* |
* psa_pake_get_implicit_key()
* psa_pake_abort()
*/
/*
* Possible sequence of calls to implementation:
*
* |--- In any order:
* | |
* | |------ In Order
* | | | mbedtls_psa_pake_output(PSA_JPAKE_X1_STEP_KEY_SHARE)
* | | | mbedtls_psa_pake_output(PSA_JPAKE_X1_STEP_ZK_PUBLIC)
* | | | mbedtls_psa_pake_output(PSA_JPAKE_X1_STEP_ZK_PROOF)
* | | | mbedtls_psa_pake_output(PSA_JPAKE_X2_STEP_KEY_SHARE)
* | | | mbedtls_psa_pake_output(PSA_JPAKE_X2_STEP_ZK_PUBLIC)
* | | | mbedtls_psa_pake_output(PSA_JPAKE_X2_STEP_ZK_PROOF)
* | |
* | |------ In Order:
* | | mbedtls_psa_pake_input(PSA_JPAKE_X1_STEP_KEY_SHARE)
* | | mbedtls_psa_pake_input(PSA_JPAKE_X1_STEP_ZK_PUBLIC)
* | | mbedtls_psa_pake_input(PSA_JPAKE_X1_STEP_ZK_PROOF)
* | | mbedtls_psa_pake_input(PSA_JPAKE_X2_STEP_KEY_SHARE)
* | | mbedtls_psa_pake_input(PSA_JPAKE_X2_STEP_ZK_PUBLIC)
* | | mbedtls_psa_pake_input(PSA_JPAKE_X2_STEP_ZK_PROOF)
* |
* |--- In any order:
* | |
* | |------ In Order
* | | | mbedtls_psa_pake_output(PSA_JPAKE_X2S_STEP_KEY_SHARE)
* | | | mbedtls_psa_pake_output(PSA_JPAKE_X2S_STEP_ZK_PUBLIC)
* | | | mbedtls_psa_pake_output(PSA_JPAKE_X2S_STEP_ZK_PROOF)
* | |
* | |------ In Order:
* | | mbedtls_psa_pake_input(PSA_JPAKE_X4S_STEP_KEY_SHARE)
* | | mbedtls_psa_pake_input(PSA_JPAKE_X4S_STEP_ZK_PUBLIC)
* | | mbedtls_psa_pake_input(PSA_JPAKE_X4S_STEP_ZK_PROOF)
*/
#if defined(MBEDTLS_PSA_BUILTIN_ALG_JPAKE)
static psa_status_t mbedtls_ecjpake_to_psa_error(int ret)
{
switch (ret) {
case MBEDTLS_ERR_MPI_BAD_INPUT_DATA:
case MBEDTLS_ERR_ECP_BAD_INPUT_DATA:
case MBEDTLS_ERR_ECP_INVALID_KEY:
case MBEDTLS_ERR_ECP_VERIFY_FAILED:
return PSA_ERROR_DATA_INVALID;
case MBEDTLS_ERR_MPI_BUFFER_TOO_SMALL:
case MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL:
return PSA_ERROR_BUFFER_TOO_SMALL;
case MBEDTLS_ERR_MD_FEATURE_UNAVAILABLE:
return PSA_ERROR_NOT_SUPPORTED;
case MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED:
return PSA_ERROR_CORRUPTION_DETECTED;
default:
return PSA_ERROR_GENERIC_ERROR;
}
}
#endif
#if defined(MBEDTLS_PSA_BUILTIN_PAKE)
#if defined(MBEDTLS_PSA_BUILTIN_ALG_JPAKE)
static psa_status_t psa_pake_ecjpake_setup(mbedtls_psa_pake_operation_t *operation)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
mbedtls_ecjpake_init(&operation->ctx.jpake);
ret = mbedtls_ecjpake_setup(&operation->ctx.jpake,
operation->role,
MBEDTLS_MD_SHA256,
MBEDTLS_ECP_DP_SECP256R1,
operation->password,
operation->password_len);
mbedtls_platform_zeroize(operation->password, operation->password_len);
if (ret != 0) {
return mbedtls_ecjpake_to_psa_error(ret);
}
return PSA_SUCCESS;
}
#endif
/* The only two JPAKE user/peer identifiers supported in built-in implementation. */
static const uint8_t jpake_server_id[] = { 's', 'e', 'r', 'v', 'e', 'r' };
static const uint8_t jpake_client_id[] = { 'c', 'l', 'i', 'e', 'n', 't' };
psa_status_t mbedtls_psa_pake_setup(mbedtls_psa_pake_operation_t *operation,
const psa_crypto_driver_pake_inputs_t *inputs)
{
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
size_t user_len = 0, peer_len = 0, password_len = 0;
uint8_t *peer = NULL, *user = NULL;
size_t actual_user_len = 0, actual_peer_len = 0, actual_password_len = 0;
psa_pake_cipher_suite_t cipher_suite = psa_pake_cipher_suite_init();
status = psa_crypto_driver_pake_get_password_len(inputs, &password_len);
if (status != PSA_SUCCESS) {
return status;
}
status = psa_crypto_driver_pake_get_user_len(inputs, &user_len);
if (status != PSA_SUCCESS) {
return status;
}
status = psa_crypto_driver_pake_get_peer_len(inputs, &peer_len);
if (status != PSA_SUCCESS) {
return status;
}
status = psa_crypto_driver_pake_get_cipher_suite(inputs, &cipher_suite);
if (status != PSA_SUCCESS) {
return status;
}
operation->password = mbedtls_calloc(1, password_len);
if (operation->password == NULL) {
status = PSA_ERROR_INSUFFICIENT_MEMORY;
goto error;
}
user = mbedtls_calloc(1, user_len);
if (user == NULL) {
status = PSA_ERROR_INSUFFICIENT_MEMORY;
goto error;
}
peer = mbedtls_calloc(1, peer_len);
if (peer == NULL) {
status = PSA_ERROR_INSUFFICIENT_MEMORY;
goto error;
}
status = psa_crypto_driver_pake_get_password(inputs, operation->password,
password_len, &actual_password_len);
if (status != PSA_SUCCESS) {
goto error;
}
status = psa_crypto_driver_pake_get_user(inputs, user,
user_len, &actual_user_len);
if (status != PSA_SUCCESS) {
goto error;
}
status = psa_crypto_driver_pake_get_peer(inputs, peer,
peer_len, &actual_peer_len);
if (status != PSA_SUCCESS) {
goto error;
}
operation->password_len = actual_password_len;
operation->alg = cipher_suite.algorithm;
#if defined(MBEDTLS_PSA_BUILTIN_ALG_JPAKE)
if (cipher_suite.algorithm == PSA_ALG_JPAKE) {
if (cipher_suite.type != PSA_PAKE_PRIMITIVE_TYPE_ECC ||
cipher_suite.family != PSA_ECC_FAMILY_SECP_R1 ||
cipher_suite.bits != 256 ||
cipher_suite.hash != PSA_ALG_SHA_256) {
status = PSA_ERROR_NOT_SUPPORTED;
goto error;
}
const size_t user_peer_len = sizeof(jpake_client_id); // client and server have the same length
if (actual_user_len != user_peer_len ||
actual_peer_len != user_peer_len) {
status = PSA_ERROR_NOT_SUPPORTED;
goto error;
}
if (memcmp(user, jpake_client_id, actual_user_len) == 0 &&
memcmp(peer, jpake_server_id, actual_peer_len) == 0) {
operation->role = MBEDTLS_ECJPAKE_CLIENT;
} else
if (memcmp(user, jpake_server_id, actual_user_len) == 0 &&
memcmp(peer, jpake_client_id, actual_peer_len) == 0) {
operation->role = MBEDTLS_ECJPAKE_SERVER;
} else {
status = PSA_ERROR_NOT_SUPPORTED;
goto error;
}
operation->buffer_length = 0;
operation->buffer_offset = 0;
status = psa_pake_ecjpake_setup(operation);
if (status != PSA_SUCCESS) {
goto error;
}
/* Role has been set, release user/peer buffers. */
mbedtls_free(user); mbedtls_free(peer);
return PSA_SUCCESS;
} else
#else
(void) operation;
(void) inputs;
#endif
{ status = PSA_ERROR_NOT_SUPPORTED; }
error:
mbedtls_free(user); mbedtls_free(peer);
/* In case of failure of the setup of a multipart operation, the PSA driver interface
* specifies that the core does not call any other driver entry point thus does not
* call mbedtls_psa_pake_abort(). Therefore call it here to do the needed clean
* up like freeing the memory that may have been allocated to store the password.
*/
mbedtls_psa_pake_abort(operation);
return status;
}
static psa_status_t mbedtls_psa_pake_output_internal(
mbedtls_psa_pake_operation_t *operation,
psa_crypto_driver_pake_step_t step,
uint8_t *output,
size_t output_size,
size_t *output_length)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
size_t length;
(void) step; // Unused parameter
#if defined(MBEDTLS_PSA_BUILTIN_ALG_JPAKE)
/*
* The PSA CRYPTO PAKE and Mbed TLS JPAKE API have a different
* handling of output sequencing.
*
* The Mbed TLS JPAKE API outputs the whole X1+X2 and X2S steps data
* at once, on the other side the PSA CRYPTO PAKE api requires
* the KEY_SHARE/ZP_PUBLIC/ZK_PROOF parts of X1, X2 & X2S to be
* retrieved in sequence.
*
* In order to achieve API compatibility, the whole X1+X2 or X2S steps
* data is stored in an intermediate buffer at first step output call,
* and data is sliced down by parsing the ECPoint records in order
* to return the right parts on each step.
*/
if (operation->alg == PSA_ALG_JPAKE) {
/* Initialize & write round on KEY_SHARE sequences */
if (step == PSA_JPAKE_X1_STEP_KEY_SHARE) {
ret = mbedtls_ecjpake_write_round_one(&operation->ctx.jpake,
operation->buffer,
sizeof(operation->buffer),
&operation->buffer_length,
mbedtls_psa_get_random,
MBEDTLS_PSA_RANDOM_STATE);
if (ret != 0) {
return mbedtls_ecjpake_to_psa_error(ret);
}
operation->buffer_offset = 0;
} else if (step == PSA_JPAKE_X2S_STEP_KEY_SHARE) {
ret = mbedtls_ecjpake_write_round_two(&operation->ctx.jpake,
operation->buffer,
sizeof(operation->buffer),
&operation->buffer_length,
mbedtls_psa_get_random,
MBEDTLS_PSA_RANDOM_STATE);
if (ret != 0) {
return mbedtls_ecjpake_to_psa_error(ret);
}
operation->buffer_offset = 0;
}
/*
* mbedtls_ecjpake_write_round_xxx() outputs thing in the format
* defined by draft-cragie-tls-ecjpake-01 section 7. The summary is
* that the data for each step is prepended with a length byte, and
* then they're concatenated. Additionally, the server's second round
* output is prepended with a 3-bytes ECParameters structure.
*
* In PSA, we output each step separately, and don't prepend the
* output with a length byte, even less a curve identifier, as that
* information is already available.
*/
if (step == PSA_JPAKE_X2S_STEP_KEY_SHARE &&
operation->role == MBEDTLS_ECJPAKE_SERVER) {
/* Skip ECParameters, with is 3 bytes (RFC 8422) */
operation->buffer_offset += 3;
}
/* Read the length byte then move past it to the data */
length = operation->buffer[operation->buffer_offset];
operation->buffer_offset += 1;
if (operation->buffer_offset + length > operation->buffer_length) {
return PSA_ERROR_DATA_CORRUPT;
}
if (output_size < length) {
return PSA_ERROR_BUFFER_TOO_SMALL;
}
memcpy(output,
operation->buffer + operation->buffer_offset,
length);
*output_length = length;
operation->buffer_offset += length;
/* Reset buffer after ZK_PROOF sequence */
if ((step == PSA_JPAKE_X2_STEP_ZK_PROOF) ||
(step == PSA_JPAKE_X2S_STEP_ZK_PROOF)) {
mbedtls_platform_zeroize(operation->buffer, sizeof(operation->buffer));
operation->buffer_length = 0;
operation->buffer_offset = 0;
}
return PSA_SUCCESS;
} else
#else
(void) step;
(void) output;
(void) output_size;
(void) output_length;
#endif
{ return PSA_ERROR_NOT_SUPPORTED; }
}
psa_status_t mbedtls_psa_pake_output(mbedtls_psa_pake_operation_t *operation,
psa_crypto_driver_pake_step_t step,
uint8_t *output,
size_t output_size,
size_t *output_length)
{
psa_status_t status = mbedtls_psa_pake_output_internal(
operation, step, output, output_size, output_length);
return status;
}
static psa_status_t mbedtls_psa_pake_input_internal(
mbedtls_psa_pake_operation_t *operation,
psa_crypto_driver_pake_step_t step,
const uint8_t *input,
size_t input_length)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
(void) step; // Unused parameter
#if defined(MBEDTLS_PSA_BUILTIN_ALG_JPAKE)
/*
* The PSA CRYPTO PAKE and Mbed TLS JPAKE API have a different
* handling of input sequencing.
*
* The Mbed TLS JPAKE API takes the whole X1+X2 or X4S steps data
* at once as input, on the other side the PSA CRYPTO PAKE api requires
* the KEY_SHARE/ZP_PUBLIC/ZK_PROOF parts of X1, X2 & X4S to be
* given in sequence.
*
* In order to achieve API compatibility, each X1+X2 or X4S step data
* is stored sequentially in an intermediate buffer and given to the
* Mbed TLS JPAKE API on the last step.
*
* This causes any input error to be only detected on the last step.
*/
if (operation->alg == PSA_ALG_JPAKE) {
/*
* Copy input to local buffer and format it as the Mbed TLS API
* expects, i.e. as defined by draft-cragie-tls-ecjpake-01 section 7.
* The summary is that the data for each step is prepended with a
* length byte, and then they're concatenated. Additionally, the
* server's second round output is prepended with a 3-bytes
* ECParameters structure - which means we have to prepend that when
* we're a client.
*/
if (step == PSA_JPAKE_X4S_STEP_KEY_SHARE &&
operation->role == MBEDTLS_ECJPAKE_CLIENT) {
/* We only support secp256r1. */
/* This is the ECParameters structure defined by RFC 8422. */
unsigned char ecparameters[3] = {
3, /* named_curve */
0, 23 /* secp256r1 */
};
if (operation->buffer_length + sizeof(ecparameters) >
sizeof(operation->buffer)) {
return PSA_ERROR_BUFFER_TOO_SMALL;
}
memcpy(operation->buffer + operation->buffer_length,
ecparameters, sizeof(ecparameters));
operation->buffer_length += sizeof(ecparameters);
}
/*
* The core checks that input_length is smaller than
* PSA_PAKE_INPUT_MAX_SIZE.
* Thus no risk of integer overflow here.
*/
if (operation->buffer_length + input_length + 1 > sizeof(operation->buffer)) {
return PSA_ERROR_BUFFER_TOO_SMALL;
}
/* Write the length byte */
operation->buffer[operation->buffer_length] = (uint8_t) input_length;
operation->buffer_length += 1;
/* Finally copy the data */
memcpy(operation->buffer + operation->buffer_length,
input, input_length);
operation->buffer_length += input_length;
/* Load buffer at each last round ZK_PROOF */
if (step == PSA_JPAKE_X2_STEP_ZK_PROOF) {
ret = mbedtls_ecjpake_read_round_one(&operation->ctx.jpake,
operation->buffer,
operation->buffer_length);
mbedtls_platform_zeroize(operation->buffer, sizeof(operation->buffer));
operation->buffer_length = 0;
if (ret != 0) {
return mbedtls_ecjpake_to_psa_error(ret);
}
} else if (step == PSA_JPAKE_X4S_STEP_ZK_PROOF) {
ret = mbedtls_ecjpake_read_round_two(&operation->ctx.jpake,
operation->buffer,
operation->buffer_length);
mbedtls_platform_zeroize(operation->buffer, sizeof(operation->buffer));
operation->buffer_length = 0;
if (ret != 0) {
return mbedtls_ecjpake_to_psa_error(ret);
}
}
return PSA_SUCCESS;
} else
#else
(void) step;
(void) input;
(void) input_length;
#endif
{ return PSA_ERROR_NOT_SUPPORTED; }
}
psa_status_t mbedtls_psa_pake_input(mbedtls_psa_pake_operation_t *operation,
psa_crypto_driver_pake_step_t step,
const uint8_t *input,
size_t input_length)
{
psa_status_t status = mbedtls_psa_pake_input_internal(
operation, step, input, input_length);
return status;
}
psa_status_t mbedtls_psa_pake_get_implicit_key(
mbedtls_psa_pake_operation_t *operation,
uint8_t *output, size_t output_size,
size_t *output_length)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
#if defined(MBEDTLS_PSA_BUILTIN_ALG_JPAKE)
if (operation->alg == PSA_ALG_JPAKE) {
ret = mbedtls_ecjpake_write_shared_key(&operation->ctx.jpake,
output,
output_size,
output_length,
mbedtls_psa_get_random,
MBEDTLS_PSA_RANDOM_STATE);
if (ret != 0) {
return mbedtls_ecjpake_to_psa_error(ret);
}
return PSA_SUCCESS;
} else
#else
(void) output;
#endif
{ return PSA_ERROR_NOT_SUPPORTED; }
}
psa_status_t mbedtls_psa_pake_abort(mbedtls_psa_pake_operation_t *operation)
{
mbedtls_zeroize_and_free(operation->password, operation->password_len);
operation->password = NULL;
operation->password_len = 0;
#if defined(MBEDTLS_PSA_BUILTIN_ALG_JPAKE)
if (operation->alg == PSA_ALG_JPAKE) {
operation->role = MBEDTLS_ECJPAKE_NONE;
mbedtls_platform_zeroize(operation->buffer, sizeof(operation->buffer));
operation->buffer_length = 0;
operation->buffer_offset = 0;
mbedtls_ecjpake_free(&operation->ctx.jpake);
}
#endif
operation->alg = PSA_ALG_NONE;
return PSA_SUCCESS;
}
#endif /* MBEDTLS_PSA_BUILTIN_PAKE */
#endif /* MBEDTLS_PSA_CRYPTO_C */