524 lines
16 KiB
C
524 lines
16 KiB
C
/**
|
|
* \file chachapoly.c
|
|
*
|
|
* \brief ChaCha20-Poly1305 AEAD construction based on RFC 7539.
|
|
*
|
|
* 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_CHACHAPOLY_C)
|
|
|
|
#include "mbedtls/chachapoly.h"
|
|
#include "mbedtls/platform_util.h"
|
|
#include "mbedtls/error.h"
|
|
#include "mbedtls/constant_time.h"
|
|
|
|
#include <string.h>
|
|
|
|
#include "mbedtls/platform.h"
|
|
|
|
#if !defined(MBEDTLS_CHACHAPOLY_ALT)
|
|
|
|
/* Parameter validation macros */
|
|
#define CHACHAPOLY_VALIDATE_RET(cond) \
|
|
MBEDTLS_INTERNAL_VALIDATE_RET(cond, MBEDTLS_ERR_POLY1305_BAD_INPUT_DATA)
|
|
#define CHACHAPOLY_VALIDATE(cond) \
|
|
MBEDTLS_INTERNAL_VALIDATE(cond)
|
|
|
|
#define CHACHAPOLY_STATE_INIT (0)
|
|
#define CHACHAPOLY_STATE_AAD (1)
|
|
#define CHACHAPOLY_STATE_CIPHERTEXT (2) /* Encrypting or decrypting */
|
|
#define CHACHAPOLY_STATE_FINISHED (3)
|
|
|
|
/**
|
|
* \brief Adds nul bytes to pad the AAD for Poly1305.
|
|
*
|
|
* \param ctx The ChaCha20-Poly1305 context.
|
|
*/
|
|
static int chachapoly_pad_aad(mbedtls_chachapoly_context *ctx)
|
|
{
|
|
uint32_t partial_block_len = (uint32_t) (ctx->aad_len % 16U);
|
|
unsigned char zeroes[15];
|
|
|
|
if (partial_block_len == 0U) {
|
|
return 0;
|
|
}
|
|
|
|
memset(zeroes, 0, sizeof(zeroes));
|
|
|
|
return mbedtls_poly1305_update(&ctx->poly1305_ctx,
|
|
zeroes,
|
|
16U - partial_block_len);
|
|
}
|
|
|
|
/**
|
|
* \brief Adds nul bytes to pad the ciphertext for Poly1305.
|
|
*
|
|
* \param ctx The ChaCha20-Poly1305 context.
|
|
*/
|
|
static int chachapoly_pad_ciphertext(mbedtls_chachapoly_context *ctx)
|
|
{
|
|
uint32_t partial_block_len = (uint32_t) (ctx->ciphertext_len % 16U);
|
|
unsigned char zeroes[15];
|
|
|
|
if (partial_block_len == 0U) {
|
|
return 0;
|
|
}
|
|
|
|
memset(zeroes, 0, sizeof(zeroes));
|
|
return mbedtls_poly1305_update(&ctx->poly1305_ctx,
|
|
zeroes,
|
|
16U - partial_block_len);
|
|
}
|
|
|
|
void mbedtls_chachapoly_init(mbedtls_chachapoly_context *ctx)
|
|
{
|
|
CHACHAPOLY_VALIDATE(ctx != NULL);
|
|
|
|
mbedtls_chacha20_init(&ctx->chacha20_ctx);
|
|
mbedtls_poly1305_init(&ctx->poly1305_ctx);
|
|
ctx->aad_len = 0U;
|
|
ctx->ciphertext_len = 0U;
|
|
ctx->state = CHACHAPOLY_STATE_INIT;
|
|
ctx->mode = MBEDTLS_CHACHAPOLY_ENCRYPT;
|
|
}
|
|
|
|
void mbedtls_chachapoly_free(mbedtls_chachapoly_context *ctx)
|
|
{
|
|
if (ctx == NULL) {
|
|
return;
|
|
}
|
|
|
|
mbedtls_chacha20_free(&ctx->chacha20_ctx);
|
|
mbedtls_poly1305_free(&ctx->poly1305_ctx);
|
|
ctx->aad_len = 0U;
|
|
ctx->ciphertext_len = 0U;
|
|
ctx->state = CHACHAPOLY_STATE_INIT;
|
|
ctx->mode = MBEDTLS_CHACHAPOLY_ENCRYPT;
|
|
}
|
|
|
|
int mbedtls_chachapoly_setkey(mbedtls_chachapoly_context *ctx,
|
|
const unsigned char key[32])
|
|
{
|
|
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
|
|
CHACHAPOLY_VALIDATE_RET(ctx != NULL);
|
|
CHACHAPOLY_VALIDATE_RET(key != NULL);
|
|
|
|
ret = mbedtls_chacha20_setkey(&ctx->chacha20_ctx, key);
|
|
|
|
return ret;
|
|
}
|
|
|
|
int mbedtls_chachapoly_starts(mbedtls_chachapoly_context *ctx,
|
|
const unsigned char nonce[12],
|
|
mbedtls_chachapoly_mode_t mode)
|
|
{
|
|
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
|
|
unsigned char poly1305_key[64];
|
|
CHACHAPOLY_VALIDATE_RET(ctx != NULL);
|
|
CHACHAPOLY_VALIDATE_RET(nonce != NULL);
|
|
|
|
/* Set counter = 0, will be update to 1 when generating Poly1305 key */
|
|
ret = mbedtls_chacha20_starts(&ctx->chacha20_ctx, nonce, 0U);
|
|
if (ret != 0) {
|
|
goto cleanup;
|
|
}
|
|
|
|
/* Generate the Poly1305 key by getting the ChaCha20 keystream output with
|
|
* counter = 0. This is the same as encrypting a buffer of zeroes.
|
|
* Only the first 256-bits (32 bytes) of the key is used for Poly1305.
|
|
* The other 256 bits are discarded.
|
|
*/
|
|
memset(poly1305_key, 0, sizeof(poly1305_key));
|
|
ret = mbedtls_chacha20_update(&ctx->chacha20_ctx, sizeof(poly1305_key),
|
|
poly1305_key, poly1305_key);
|
|
if (ret != 0) {
|
|
goto cleanup;
|
|
}
|
|
|
|
ret = mbedtls_poly1305_starts(&ctx->poly1305_ctx, poly1305_key);
|
|
|
|
if (ret == 0) {
|
|
ctx->aad_len = 0U;
|
|
ctx->ciphertext_len = 0U;
|
|
ctx->state = CHACHAPOLY_STATE_AAD;
|
|
ctx->mode = mode;
|
|
}
|
|
|
|
cleanup:
|
|
mbedtls_platform_zeroize(poly1305_key, 64U);
|
|
return ret;
|
|
}
|
|
|
|
int mbedtls_chachapoly_update_aad(mbedtls_chachapoly_context *ctx,
|
|
const unsigned char *aad,
|
|
size_t aad_len)
|
|
{
|
|
CHACHAPOLY_VALIDATE_RET(ctx != NULL);
|
|
CHACHAPOLY_VALIDATE_RET(aad_len == 0 || aad != NULL);
|
|
|
|
if (ctx->state != CHACHAPOLY_STATE_AAD) {
|
|
return MBEDTLS_ERR_CHACHAPOLY_BAD_STATE;
|
|
}
|
|
|
|
ctx->aad_len += aad_len;
|
|
|
|
return mbedtls_poly1305_update(&ctx->poly1305_ctx, aad, aad_len);
|
|
}
|
|
|
|
int mbedtls_chachapoly_update(mbedtls_chachapoly_context *ctx,
|
|
size_t len,
|
|
const unsigned char *input,
|
|
unsigned char *output)
|
|
{
|
|
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
|
|
CHACHAPOLY_VALIDATE_RET(ctx != NULL);
|
|
CHACHAPOLY_VALIDATE_RET(len == 0 || input != NULL);
|
|
CHACHAPOLY_VALIDATE_RET(len == 0 || output != NULL);
|
|
|
|
if ((ctx->state != CHACHAPOLY_STATE_AAD) &&
|
|
(ctx->state != CHACHAPOLY_STATE_CIPHERTEXT)) {
|
|
return MBEDTLS_ERR_CHACHAPOLY_BAD_STATE;
|
|
}
|
|
|
|
if (ctx->state == CHACHAPOLY_STATE_AAD) {
|
|
ctx->state = CHACHAPOLY_STATE_CIPHERTEXT;
|
|
|
|
ret = chachapoly_pad_aad(ctx);
|
|
if (ret != 0) {
|
|
return ret;
|
|
}
|
|
}
|
|
|
|
ctx->ciphertext_len += len;
|
|
|
|
if (ctx->mode == MBEDTLS_CHACHAPOLY_ENCRYPT) {
|
|
ret = mbedtls_chacha20_update(&ctx->chacha20_ctx, len, input, output);
|
|
if (ret != 0) {
|
|
return ret;
|
|
}
|
|
|
|
ret = mbedtls_poly1305_update(&ctx->poly1305_ctx, output, len);
|
|
if (ret != 0) {
|
|
return ret;
|
|
}
|
|
} else { /* DECRYPT */
|
|
ret = mbedtls_poly1305_update(&ctx->poly1305_ctx, input, len);
|
|
if (ret != 0) {
|
|
return ret;
|
|
}
|
|
|
|
ret = mbedtls_chacha20_update(&ctx->chacha20_ctx, len, input, output);
|
|
if (ret != 0) {
|
|
return ret;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
int mbedtls_chachapoly_finish(mbedtls_chachapoly_context *ctx,
|
|
unsigned char mac[16])
|
|
{
|
|
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
|
|
unsigned char len_block[16];
|
|
CHACHAPOLY_VALIDATE_RET(ctx != NULL);
|
|
CHACHAPOLY_VALIDATE_RET(mac != NULL);
|
|
|
|
if (ctx->state == CHACHAPOLY_STATE_INIT) {
|
|
return MBEDTLS_ERR_CHACHAPOLY_BAD_STATE;
|
|
}
|
|
|
|
if (ctx->state == CHACHAPOLY_STATE_AAD) {
|
|
ret = chachapoly_pad_aad(ctx);
|
|
if (ret != 0) {
|
|
return ret;
|
|
}
|
|
} else if (ctx->state == CHACHAPOLY_STATE_CIPHERTEXT) {
|
|
ret = chachapoly_pad_ciphertext(ctx);
|
|
if (ret != 0) {
|
|
return ret;
|
|
}
|
|
}
|
|
|
|
ctx->state = CHACHAPOLY_STATE_FINISHED;
|
|
|
|
/* The lengths of the AAD and ciphertext are processed by
|
|
* Poly1305 as the final 128-bit block, encoded as little-endian integers.
|
|
*/
|
|
MBEDTLS_PUT_UINT64_LE(ctx->aad_len, len_block, 0);
|
|
MBEDTLS_PUT_UINT64_LE(ctx->ciphertext_len, len_block, 8);
|
|
|
|
ret = mbedtls_poly1305_update(&ctx->poly1305_ctx, len_block, 16U);
|
|
if (ret != 0) {
|
|
return ret;
|
|
}
|
|
|
|
ret = mbedtls_poly1305_finish(&ctx->poly1305_ctx, mac);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int chachapoly_crypt_and_tag(mbedtls_chachapoly_context *ctx,
|
|
mbedtls_chachapoly_mode_t mode,
|
|
size_t length,
|
|
const unsigned char nonce[12],
|
|
const unsigned char *aad,
|
|
size_t aad_len,
|
|
const unsigned char *input,
|
|
unsigned char *output,
|
|
unsigned char tag[16])
|
|
{
|
|
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
|
|
|
|
ret = mbedtls_chachapoly_starts(ctx, nonce, mode);
|
|
if (ret != 0) {
|
|
goto cleanup;
|
|
}
|
|
|
|
ret = mbedtls_chachapoly_update_aad(ctx, aad, aad_len);
|
|
if (ret != 0) {
|
|
goto cleanup;
|
|
}
|
|
|
|
ret = mbedtls_chachapoly_update(ctx, length, input, output);
|
|
if (ret != 0) {
|
|
goto cleanup;
|
|
}
|
|
|
|
ret = mbedtls_chachapoly_finish(ctx, tag);
|
|
|
|
cleanup:
|
|
return ret;
|
|
}
|
|
|
|
int mbedtls_chachapoly_encrypt_and_tag(mbedtls_chachapoly_context *ctx,
|
|
size_t length,
|
|
const unsigned char nonce[12],
|
|
const unsigned char *aad,
|
|
size_t aad_len,
|
|
const unsigned char *input,
|
|
unsigned char *output,
|
|
unsigned char tag[16])
|
|
{
|
|
CHACHAPOLY_VALIDATE_RET(ctx != NULL);
|
|
CHACHAPOLY_VALIDATE_RET(nonce != NULL);
|
|
CHACHAPOLY_VALIDATE_RET(tag != NULL);
|
|
CHACHAPOLY_VALIDATE_RET(aad_len == 0 || aad != NULL);
|
|
CHACHAPOLY_VALIDATE_RET(length == 0 || input != NULL);
|
|
CHACHAPOLY_VALIDATE_RET(length == 0 || output != NULL);
|
|
|
|
return chachapoly_crypt_and_tag(ctx, MBEDTLS_CHACHAPOLY_ENCRYPT,
|
|
length, nonce, aad, aad_len,
|
|
input, output, tag);
|
|
}
|
|
|
|
int mbedtls_chachapoly_auth_decrypt(mbedtls_chachapoly_context *ctx,
|
|
size_t length,
|
|
const unsigned char nonce[12],
|
|
const unsigned char *aad,
|
|
size_t aad_len,
|
|
const unsigned char tag[16],
|
|
const unsigned char *input,
|
|
unsigned char *output)
|
|
{
|
|
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
|
|
unsigned char check_tag[16];
|
|
int diff;
|
|
CHACHAPOLY_VALIDATE_RET(ctx != NULL);
|
|
CHACHAPOLY_VALIDATE_RET(nonce != NULL);
|
|
CHACHAPOLY_VALIDATE_RET(tag != NULL);
|
|
CHACHAPOLY_VALIDATE_RET(aad_len == 0 || aad != NULL);
|
|
CHACHAPOLY_VALIDATE_RET(length == 0 || input != NULL);
|
|
CHACHAPOLY_VALIDATE_RET(length == 0 || output != NULL);
|
|
|
|
if ((ret = chachapoly_crypt_and_tag(ctx,
|
|
MBEDTLS_CHACHAPOLY_DECRYPT, length, nonce,
|
|
aad, aad_len, input, output, check_tag)) != 0) {
|
|
return ret;
|
|
}
|
|
|
|
/* Check tag in "constant-time" */
|
|
diff = mbedtls_ct_memcmp(tag, check_tag, sizeof(check_tag));
|
|
|
|
if (diff != 0) {
|
|
mbedtls_platform_zeroize(output, length);
|
|
return MBEDTLS_ERR_CHACHAPOLY_AUTH_FAILED;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
#endif /* MBEDTLS_CHACHAPOLY_ALT */
|
|
|
|
#if defined(MBEDTLS_SELF_TEST)
|
|
|
|
static const unsigned char test_key[1][32] =
|
|
{
|
|
{
|
|
0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
|
|
0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f,
|
|
0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97,
|
|
0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f
|
|
}
|
|
};
|
|
|
|
static const unsigned char test_nonce[1][12] =
|
|
{
|
|
{
|
|
0x07, 0x00, 0x00, 0x00, /* 32-bit common part */
|
|
0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47 /* 64-bit IV */
|
|
}
|
|
};
|
|
|
|
static const unsigned char test_aad[1][12] =
|
|
{
|
|
{
|
|
0x50, 0x51, 0x52, 0x53, 0xc0, 0xc1, 0xc2, 0xc3,
|
|
0xc4, 0xc5, 0xc6, 0xc7
|
|
}
|
|
};
|
|
|
|
static const size_t test_aad_len[1] =
|
|
{
|
|
12U
|
|
};
|
|
|
|
static const unsigned char test_input[1][114] =
|
|
{
|
|
{
|
|
0x4c, 0x61, 0x64, 0x69, 0x65, 0x73, 0x20, 0x61,
|
|
0x6e, 0x64, 0x20, 0x47, 0x65, 0x6e, 0x74, 0x6c,
|
|
0x65, 0x6d, 0x65, 0x6e, 0x20, 0x6f, 0x66, 0x20,
|
|
0x74, 0x68, 0x65, 0x20, 0x63, 0x6c, 0x61, 0x73,
|
|
0x73, 0x20, 0x6f, 0x66, 0x20, 0x27, 0x39, 0x39,
|
|
0x3a, 0x20, 0x49, 0x66, 0x20, 0x49, 0x20, 0x63,
|
|
0x6f, 0x75, 0x6c, 0x64, 0x20, 0x6f, 0x66, 0x66,
|
|
0x65, 0x72, 0x20, 0x79, 0x6f, 0x75, 0x20, 0x6f,
|
|
0x6e, 0x6c, 0x79, 0x20, 0x6f, 0x6e, 0x65, 0x20,
|
|
0x74, 0x69, 0x70, 0x20, 0x66, 0x6f, 0x72, 0x20,
|
|
0x74, 0x68, 0x65, 0x20, 0x66, 0x75, 0x74, 0x75,
|
|
0x72, 0x65, 0x2c, 0x20, 0x73, 0x75, 0x6e, 0x73,
|
|
0x63, 0x72, 0x65, 0x65, 0x6e, 0x20, 0x77, 0x6f,
|
|
0x75, 0x6c, 0x64, 0x20, 0x62, 0x65, 0x20, 0x69,
|
|
0x74, 0x2e
|
|
}
|
|
};
|
|
|
|
static const unsigned char test_output[1][114] =
|
|
{
|
|
{
|
|
0xd3, 0x1a, 0x8d, 0x34, 0x64, 0x8e, 0x60, 0xdb,
|
|
0x7b, 0x86, 0xaf, 0xbc, 0x53, 0xef, 0x7e, 0xc2,
|
|
0xa4, 0xad, 0xed, 0x51, 0x29, 0x6e, 0x08, 0xfe,
|
|
0xa9, 0xe2, 0xb5, 0xa7, 0x36, 0xee, 0x62, 0xd6,
|
|
0x3d, 0xbe, 0xa4, 0x5e, 0x8c, 0xa9, 0x67, 0x12,
|
|
0x82, 0xfa, 0xfb, 0x69, 0xda, 0x92, 0x72, 0x8b,
|
|
0x1a, 0x71, 0xde, 0x0a, 0x9e, 0x06, 0x0b, 0x29,
|
|
0x05, 0xd6, 0xa5, 0xb6, 0x7e, 0xcd, 0x3b, 0x36,
|
|
0x92, 0xdd, 0xbd, 0x7f, 0x2d, 0x77, 0x8b, 0x8c,
|
|
0x98, 0x03, 0xae, 0xe3, 0x28, 0x09, 0x1b, 0x58,
|
|
0xfa, 0xb3, 0x24, 0xe4, 0xfa, 0xd6, 0x75, 0x94,
|
|
0x55, 0x85, 0x80, 0x8b, 0x48, 0x31, 0xd7, 0xbc,
|
|
0x3f, 0xf4, 0xde, 0xf0, 0x8e, 0x4b, 0x7a, 0x9d,
|
|
0xe5, 0x76, 0xd2, 0x65, 0x86, 0xce, 0xc6, 0x4b,
|
|
0x61, 0x16
|
|
}
|
|
};
|
|
|
|
static const size_t test_input_len[1] =
|
|
{
|
|
114U
|
|
};
|
|
|
|
static const unsigned char test_mac[1][16] =
|
|
{
|
|
{
|
|
0x1a, 0xe1, 0x0b, 0x59, 0x4f, 0x09, 0xe2, 0x6a,
|
|
0x7e, 0x90, 0x2e, 0xcb, 0xd0, 0x60, 0x06, 0x91
|
|
}
|
|
};
|
|
|
|
/* Make sure no other definition is already present. */
|
|
#undef ASSERT
|
|
|
|
#define ASSERT(cond, args) \
|
|
do \
|
|
{ \
|
|
if (!(cond)) \
|
|
{ \
|
|
if (verbose != 0) \
|
|
mbedtls_printf args; \
|
|
\
|
|
return -1; \
|
|
} \
|
|
} \
|
|
while (0)
|
|
|
|
int mbedtls_chachapoly_self_test(int verbose)
|
|
{
|
|
mbedtls_chachapoly_context ctx;
|
|
unsigned i;
|
|
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
|
|
unsigned char output[200];
|
|
unsigned char mac[16];
|
|
|
|
for (i = 0U; i < 1U; i++) {
|
|
if (verbose != 0) {
|
|
mbedtls_printf(" ChaCha20-Poly1305 test %u ", i);
|
|
}
|
|
|
|
mbedtls_chachapoly_init(&ctx);
|
|
|
|
ret = mbedtls_chachapoly_setkey(&ctx, test_key[i]);
|
|
ASSERT(0 == ret, ("setkey() error code: %i\n", ret));
|
|
|
|
ret = mbedtls_chachapoly_encrypt_and_tag(&ctx,
|
|
test_input_len[i],
|
|
test_nonce[i],
|
|
test_aad[i],
|
|
test_aad_len[i],
|
|
test_input[i],
|
|
output,
|
|
mac);
|
|
|
|
ASSERT(0 == ret, ("crypt_and_tag() error code: %i\n", ret));
|
|
|
|
ASSERT(0 == memcmp(output, test_output[i], test_input_len[i]),
|
|
("failure (wrong output)\n"));
|
|
|
|
ASSERT(0 == memcmp(mac, test_mac[i], 16U),
|
|
("failure (wrong MAC)\n"));
|
|
|
|
mbedtls_chachapoly_free(&ctx);
|
|
|
|
if (verbose != 0) {
|
|
mbedtls_printf("passed\n");
|
|
}
|
|
}
|
|
|
|
if (verbose != 0) {
|
|
mbedtls_printf("\n");
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
#endif /* MBEDTLS_SELF_TEST */
|
|
|
|
#endif /* MBEDTLS_CHACHAPOLY_C */
|