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|
/*
* PSA AEAD entry points
*/
/*
* Copyright The Mbed TLS Contributors
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "common.h"
#if defined(MBEDTLS_PSA_CRYPTO_C)
#include "psa_crypto_aead.h"
#include "psa_crypto_core.h"
#include "psa_crypto_cipher.h"
#include "mbedtls/ccm.h"
#include "mbedtls/chachapoly.h"
#include "mbedtls/cipher.h"
#include "mbedtls/gcm.h"
typedef struct {
psa_algorithm_t core_alg;
uint8_t tag_length;
union {
unsigned dummy; /* Make the union non-empty even with no supported algorithms. */
#if defined(MBEDTLS_PSA_BUILTIN_ALG_CCM)
mbedtls_ccm_context ccm;
#endif /* MBEDTLS_PSA_BUILTIN_ALG_CCM */
#if defined(MBEDTLS_PSA_BUILTIN_ALG_GCM)
mbedtls_gcm_context gcm;
#endif /* MBEDTLS_PSA_BUILTIN_ALG_GCM */
#if defined(MBEDTLS_PSA_BUILTIN_ALG_CHACHA20_POLY1305)
mbedtls_chachapoly_context chachapoly;
#endif /* MBEDTLS_PSA_BUILTIN_ALG_CHACHA20_POLY1305 */
} ctx;
} aead_operation_t;
#define AEAD_OPERATION_INIT { 0, 0, { 0 } }
static void psa_aead_abort_internal(aead_operation_t *operation)
{
switch (operation->core_alg) {
#if defined(MBEDTLS_PSA_BUILTIN_ALG_CCM)
case PSA_ALG_CCM:
mbedtls_ccm_free(&operation->ctx.ccm);
break;
#endif /* MBEDTLS_PSA_BUILTIN_ALG_CCM */
#if defined(MBEDTLS_PSA_BUILTIN_ALG_GCM)
case PSA_ALG_GCM:
mbedtls_gcm_free(&operation->ctx.gcm);
break;
#endif /* MBEDTLS_PSA_BUILTIN_ALG_GCM */
#if defined(MBEDTLS_PSA_BUILTIN_ALG_CHACHA20_POLY1305)
case PSA_ALG_CHACHA20_POLY1305:
mbedtls_chachapoly_free(&operation->ctx.chachapoly);
break;
#endif /* MBEDTLS_PSA_BUILTIN_ALG_CHACHA20_POLY1305 */
}
}
static psa_status_t psa_aead_setup(
aead_operation_t *operation,
const psa_key_attributes_t *attributes,
const uint8_t *key_buffer,
psa_algorithm_t alg)
{
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
size_t key_bits;
const mbedtls_cipher_info_t *cipher_info;
mbedtls_cipher_id_t cipher_id;
size_t full_tag_length = 0;
key_bits = attributes->core.bits;
cipher_info = mbedtls_cipher_info_from_psa(alg,
attributes->core.type, key_bits,
&cipher_id);
if (cipher_info == NULL) {
return PSA_ERROR_NOT_SUPPORTED;
}
switch (PSA_ALG_AEAD_WITH_SHORTENED_TAG(alg, 0)) {
#if defined(MBEDTLS_PSA_BUILTIN_ALG_CCM)
case PSA_ALG_AEAD_WITH_SHORTENED_TAG(PSA_ALG_CCM, 0):
operation->core_alg = PSA_ALG_CCM;
full_tag_length = 16;
/* CCM allows the following tag lengths: 4, 6, 8, 10, 12, 14, 16.
* The call to mbedtls_ccm_encrypt_and_tag or
* mbedtls_ccm_auth_decrypt will validate the tag length. */
if (PSA_BLOCK_CIPHER_BLOCK_LENGTH(attributes->core.type) != 16) {
return PSA_ERROR_INVALID_ARGUMENT;
}
mbedtls_ccm_init(&operation->ctx.ccm);
status = mbedtls_to_psa_error(
mbedtls_ccm_setkey(&operation->ctx.ccm, cipher_id,
key_buffer, (unsigned int) key_bits));
if (status != PSA_SUCCESS) {
return status;
}
break;
#endif /* MBEDTLS_PSA_BUILTIN_ALG_CCM */
#if defined(MBEDTLS_PSA_BUILTIN_ALG_GCM)
case PSA_ALG_AEAD_WITH_SHORTENED_TAG(PSA_ALG_GCM, 0):
operation->core_alg = PSA_ALG_GCM;
full_tag_length = 16;
/* GCM allows the following tag lengths: 4, 8, 12, 13, 14, 15, 16.
* The call to mbedtls_gcm_crypt_and_tag or
* mbedtls_gcm_auth_decrypt will validate the tag length. */
if (PSA_BLOCK_CIPHER_BLOCK_LENGTH(attributes->core.type) != 16) {
return PSA_ERROR_INVALID_ARGUMENT;
}
mbedtls_gcm_init(&operation->ctx.gcm);
status = mbedtls_to_psa_error(
mbedtls_gcm_setkey(&operation->ctx.gcm, cipher_id,
key_buffer, (unsigned int) key_bits));
if (status != PSA_SUCCESS) {
return status;
}
break;
#endif /* MBEDTLS_PSA_BUILTIN_ALG_GCM */
#if defined(MBEDTLS_PSA_BUILTIN_ALG_CHACHA20_POLY1305)
case PSA_ALG_AEAD_WITH_SHORTENED_TAG(PSA_ALG_CHACHA20_POLY1305, 0):
operation->core_alg = PSA_ALG_CHACHA20_POLY1305;
full_tag_length = 16;
/* We only support the default tag length. */
if (alg != PSA_ALG_CHACHA20_POLY1305) {
return PSA_ERROR_NOT_SUPPORTED;
}
mbedtls_chachapoly_init(&operation->ctx.chachapoly);
status = mbedtls_to_psa_error(
mbedtls_chachapoly_setkey(&operation->ctx.chachapoly,
key_buffer));
if (status != PSA_SUCCESS) {
return status;
}
break;
#endif /* MBEDTLS_PSA_BUILTIN_ALG_CHACHA20_POLY1305 */
default:
(void) status;
(void) key_buffer;
return PSA_ERROR_NOT_SUPPORTED;
}
if (PSA_AEAD_TAG_LENGTH(attributes->core.type,
key_bits, alg)
> full_tag_length) {
return PSA_ERROR_INVALID_ARGUMENT;
}
operation->tag_length = PSA_AEAD_TAG_LENGTH(attributes->core.type,
key_bits,
alg);
return PSA_SUCCESS;
}
psa_status_t mbedtls_psa_aead_encrypt(
const psa_key_attributes_t *attributes,
const uint8_t *key_buffer, size_t key_buffer_size,
psa_algorithm_t alg,
const uint8_t *nonce, size_t nonce_length,
const uint8_t *additional_data, size_t additional_data_length,
const uint8_t *plaintext, size_t plaintext_length,
uint8_t *ciphertext, size_t ciphertext_size, size_t *ciphertext_length)
{
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
aead_operation_t operation = AEAD_OPERATION_INIT;
uint8_t *tag;
(void) key_buffer_size;
status = psa_aead_setup(&operation, attributes, key_buffer, alg);
if (status != PSA_SUCCESS) {
goto exit;
}
/* For all currently supported modes, the tag is at the end of the
* ciphertext. */
if (ciphertext_size < (plaintext_length + operation.tag_length)) {
status = PSA_ERROR_BUFFER_TOO_SMALL;
goto exit;
}
tag = ciphertext + plaintext_length;
#if defined(MBEDTLS_PSA_BUILTIN_ALG_CCM)
if (operation.core_alg == PSA_ALG_CCM) {
status = mbedtls_to_psa_error(
mbedtls_ccm_encrypt_and_tag(&operation.ctx.ccm,
plaintext_length,
nonce, nonce_length,
additional_data,
additional_data_length,
plaintext, ciphertext,
tag, operation.tag_length));
} else
#endif /* MBEDTLS_PSA_BUILTIN_ALG_CCM */
#if defined(MBEDTLS_PSA_BUILTIN_ALG_GCM)
if (operation.core_alg == PSA_ALG_GCM) {
status = mbedtls_to_psa_error(
mbedtls_gcm_crypt_and_tag(&operation.ctx.gcm,
MBEDTLS_GCM_ENCRYPT,
plaintext_length,
nonce, nonce_length,
additional_data, additional_data_length,
plaintext, ciphertext,
operation.tag_length, tag));
} else
#endif /* MBEDTLS_PSA_BUILTIN_ALG_GCM */
#if defined(MBEDTLS_PSA_BUILTIN_ALG_CHACHA20_POLY1305)
if (operation.core_alg == PSA_ALG_CHACHA20_POLY1305) {
if (nonce_length != 12) {
if (nonce_length == 8) {
status = PSA_ERROR_NOT_SUPPORTED;
} else {
status = PSA_ERROR_INVALID_ARGUMENT;
}
goto exit;
}
if (operation.tag_length != 16) {
status = PSA_ERROR_NOT_SUPPORTED;
goto exit;
}
status = mbedtls_to_psa_error(
mbedtls_chachapoly_encrypt_and_tag(&operation.ctx.chachapoly,
plaintext_length,
nonce,
additional_data,
additional_data_length,
plaintext,
ciphertext,
tag));
} else
#endif /* MBEDTLS_PSA_BUILTIN_ALG_CHACHA20_POLY1305 */
{
(void) tag;
(void) nonce;
(void) nonce_length;
(void) additional_data;
(void) additional_data_length;
(void) plaintext;
return PSA_ERROR_NOT_SUPPORTED;
}
if (status == PSA_SUCCESS) {
*ciphertext_length = plaintext_length + operation.tag_length;
}
exit:
psa_aead_abort_internal(&operation);
return status;
}
/* Locate the tag in a ciphertext buffer containing the encrypted data
* followed by the tag. Return the length of the part preceding the tag in
* *plaintext_length. This is the size of the plaintext in modes where
* the encrypted data has the same size as the plaintext, such as
* CCM and GCM. */
static psa_status_t psa_aead_unpadded_locate_tag(size_t tag_length,
const uint8_t *ciphertext,
size_t ciphertext_length,
size_t plaintext_size,
const uint8_t **p_tag)
{
size_t payload_length;
if (tag_length > ciphertext_length) {
return PSA_ERROR_INVALID_ARGUMENT;
}
payload_length = ciphertext_length - tag_length;
if (payload_length > plaintext_size) {
return PSA_ERROR_BUFFER_TOO_SMALL;
}
*p_tag = ciphertext + payload_length;
return PSA_SUCCESS;
}
psa_status_t mbedtls_psa_aead_decrypt(
const psa_key_attributes_t *attributes,
const uint8_t *key_buffer, size_t key_buffer_size,
psa_algorithm_t alg,
const uint8_t *nonce, size_t nonce_length,
const uint8_t *additional_data, size_t additional_data_length,
const uint8_t *ciphertext, size_t ciphertext_length,
uint8_t *plaintext, size_t plaintext_size, size_t *plaintext_length)
{
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
aead_operation_t operation = AEAD_OPERATION_INIT;
const uint8_t *tag = NULL;
(void) key_buffer_size;
status = psa_aead_setup(&operation, attributes, key_buffer, alg);
if (status != PSA_SUCCESS) {
goto exit;
}
status = psa_aead_unpadded_locate_tag(operation.tag_length,
ciphertext, ciphertext_length,
plaintext_size, &tag);
if (status != PSA_SUCCESS) {
goto exit;
}
#if defined(MBEDTLS_PSA_BUILTIN_ALG_CCM)
if (operation.core_alg == PSA_ALG_CCM) {
status = mbedtls_to_psa_error(
mbedtls_ccm_auth_decrypt(&operation.ctx.ccm,
ciphertext_length - operation.tag_length,
nonce, nonce_length,
additional_data,
additional_data_length,
ciphertext, plaintext,
tag, operation.tag_length));
} else
#endif /* MBEDTLS_PSA_BUILTIN_ALG_CCM */
#if defined(MBEDTLS_PSA_BUILTIN_ALG_GCM)
if (operation.core_alg == PSA_ALG_GCM) {
status = mbedtls_to_psa_error(
mbedtls_gcm_auth_decrypt(&operation.ctx.gcm,
ciphertext_length - operation.tag_length,
nonce, nonce_length,
additional_data,
additional_data_length,
tag, operation.tag_length,
ciphertext, plaintext));
} else
#endif /* MBEDTLS_PSA_BUILTIN_ALG_GCM */
#if defined(MBEDTLS_PSA_BUILTIN_ALG_CHACHA20_POLY1305)
if (operation.core_alg == PSA_ALG_CHACHA20_POLY1305) {
if (nonce_length != 12) {
if (nonce_length == 8) {
status = PSA_ERROR_NOT_SUPPORTED;
} else {
status = PSA_ERROR_INVALID_ARGUMENT;
}
goto exit;
}
if (operation.tag_length != 16) {
status = PSA_ERROR_NOT_SUPPORTED;
goto exit;
}
status = mbedtls_to_psa_error(
mbedtls_chachapoly_auth_decrypt(&operation.ctx.chachapoly,
ciphertext_length - operation.tag_length,
nonce,
additional_data,
additional_data_length,
tag,
ciphertext,
plaintext));
} else
#endif /* MBEDTLS_PSA_BUILTIN_ALG_CHACHA20_POLY1305 */
{
(void) nonce;
(void) nonce_length;
(void) additional_data;
(void) additional_data_length;
(void) plaintext;
return PSA_ERROR_NOT_SUPPORTED;
}
if (status == PSA_SUCCESS) {
*plaintext_length = ciphertext_length - operation.tag_length;
}
exit:
psa_aead_abort_internal(&operation);
if (status == PSA_SUCCESS) {
*plaintext_length = ciphertext_length - operation.tag_length;
}
return status;
}
#endif /* MBEDTLS_PSA_CRYPTO_C */
|
