int
avs_crypto_aead_aes_ccm_decrypt(const unsigned char *key, size_t key_len,
const unsigned char *iv, size_t iv_len,
const unsigned char *aad, size_t aad_len,
const unsigned char *input, size_t input_len,
const unsigned char *tag, size_t tag_len,
unsigned char *output) {
assert(key);
assert(iv);
assert(!aad_len || aad);
assert(!input_len || input);
assert(tag);
assert(!input_len || output);
if (!_avs_crypto_aead_parameters_valid(key_len, iv_len, tag_len)) {
return -1;
}
mbedtls_ccm_context ccm_ctx;
mbedtls_ccm_init(&ccm_ctx);
int result;
(void) ((result = mbedtls_ccm_setkey(&ccm_ctx, MBEDTLS_CIPHER_ID_AES, key,
(unsigned int) key_len * 8U))
|| (result = mbedtls_ccm_auth_decrypt(&ccm_ctx, input_len,
iv, iv_len, aad, aad_len,
input, output, tag,
tag_len)));
mbedtls_ccm_free(&ccm_ctx);
if (result) {
LOG(ERROR, "mbed TLS error %d", result);
return -1;
}
return 0;
}
bool AES_CCM_Decrypt(COSE_Enveloped * pcose, int TSize, int LSize, const byte * pbKey, size_t cbKey, const byte * pbCrypto, size_t cbCrypto, const byte * pbAuthData, size_t cbAuthData, cose_errback * perr)
{
mbedtls_ccm_context ctx;
int cbOut;
byte * rgbOut = NULL;
int NSize = 15 - (LSize/8);
byte rgbIV[15] = { 0 };
const cn_cbor * pIV = NULL;
mbedtls_cipher_id_t cipher;
#ifdef USE_CBOR_CONTEXT
cn_cbor_context * context = &pcose->m_message.m_allocContext;
#endif
mbedtls_ccm_init(&ctx);
// Setup the IV/Nonce and put it into the message
pIV = _COSE_map_get_int(&pcose->m_message, COSE_Header_IV, COSE_BOTH, NULL);
if ((pIV == NULL) || (pIV->type!= CN_CBOR_BYTES)) {
if (perr != NULL) perr->err = COSE_ERR_INVALID_PARAMETER;
errorReturn:
if (rgbOut != NULL) COSE_FREE(rgbOut, context);
mbedtls_ccm_free(&ctx);
return false;
}
CHECK_CONDITION(pIV->length == NSize, COSE_ERR_INVALID_PARAMETER);
memcpy(rgbIV, pIV->v.str, pIV->length);
// Setup and run the mbedTLS code
cipher = MBEDTLS_CIPHER_ID_AES;
CHECK_CONDITION(!mbedtls_ccm_setkey(&ctx, cipher, pbKey, cbKey*8), COSE_ERR_CRYPTO_FAIL);
TSize /= 8; // Comes in in bits not bytes.
cbOut = (int) cbCrypto - TSize;
rgbOut = (byte *)COSE_CALLOC(cbOut, 1, context);
CHECK_CONDITION(rgbOut != NULL, COSE_ERR_OUT_OF_MEMORY);
CHECK_CONDITION(!mbedtls_ccm_auth_decrypt(&ctx, cbOut, rgbIV, NSize, pbAuthData, cbAuthData, pbCrypto, rgbOut, &pbCrypto[cbOut], TSize), COSE_ERR_CRYPTO_FAIL);
mbedtls_ccm_free(&ctx);
pcose->pbContent = rgbOut;
pcose->cbContent = cbOut;
return true;
}
/*
* Packet-oriented decryption for AEAD modes
*/
int mbedtls_cipher_auth_decrypt( mbedtls_cipher_context_t *ctx,
const unsigned char *iv, size_t iv_len,
const unsigned char *ad, size_t ad_len,
const unsigned char *input, size_t ilen,
unsigned char *output, size_t *olen,
const unsigned char *tag, size_t tag_len )
{
#if defined(MBEDTLS_GCM_C)
if( MBEDTLS_MODE_GCM == ctx->cipher_info->mode )
{
int ret;
*olen = ilen;
ret = mbedtls_gcm_auth_decrypt( ctx->cipher_ctx, ilen,
iv, iv_len, ad, ad_len,
tag, tag_len, input, output );
if( ret == MBEDTLS_ERR_GCM_AUTH_FAILED )
ret = MBEDTLS_ERR_CIPHER_AUTH_FAILED;
return( ret );
}
#endif /* MBEDTLS_GCM_C */
#if defined(MBEDTLS_CCM_C)
if( MBEDTLS_MODE_CCM == ctx->cipher_info->mode )
{
int ret;
*olen = ilen;
ret = mbedtls_ccm_auth_decrypt( ctx->cipher_ctx, ilen,
iv, iv_len, ad, ad_len,
input, output, tag, tag_len );
if( ret == MBEDTLS_ERR_CCM_AUTH_FAILED )
ret = MBEDTLS_ERR_CIPHER_AUTH_FAILED;
return( ret );
}
#endif /* MBEDTLS_CCM_C */
return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE );
}
/*
* Packet-oriented decryption for AEAD modes
*/
int mbedtls_cipher_auth_decrypt( mbedtls_cipher_context_t *ctx,
const unsigned char *iv, size_t iv_len,
const unsigned char *ad, size_t ad_len,
const unsigned char *input, size_t ilen,
unsigned char *output, size_t *olen,
const unsigned char *tag, size_t tag_len )
{
#if defined(MBEDTLS_GCM_C)
if( MBEDTLS_MODE_GCM == ctx->cipher_info->mode )
{
int ret;
*olen = ilen;
ret = mbedtls_gcm_auth_decrypt( ctx->cipher_ctx, ilen,
iv, iv_len, ad, ad_len,
tag, tag_len, input, output );
if( ret == MBEDTLS_ERR_GCM_AUTH_FAILED )
ret = MBEDTLS_ERR_CIPHER_AUTH_FAILED;
return( ret );
}
#endif /* MBEDTLS_GCM_C */
#if defined(MBEDTLS_CCM_C)
if( MBEDTLS_MODE_CCM == ctx->cipher_info->mode )
{
int ret;
*olen = ilen;
ret = mbedtls_ccm_auth_decrypt( ctx->cipher_ctx, ilen,
iv, iv_len, ad, ad_len,
input, output, tag, tag_len );
if( ret == MBEDTLS_ERR_CCM_AUTH_FAILED )
ret = MBEDTLS_ERR_CIPHER_AUTH_FAILED;
return( ret );
}
#endif /* MBEDTLS_CCM_C */
#if defined(MBEDTLS_CHACHAPOLY_C)
if ( MBEDTLS_CIPHER_CHACHA20_POLY1305 == ctx->cipher_info->type )
{
int ret;
/* ChachaPoly has fixed length nonce and MAC (tag) */
if ( ( iv_len != ctx->cipher_info->iv_size ) ||
( tag_len != 16U ) )
{
return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
}
*olen = ilen;
ret = mbedtls_chachapoly_auth_decrypt( ctx->cipher_ctx, ilen,
iv, ad, ad_len, tag, input, output );
if( ret == MBEDTLS_ERR_CHACHAPOLY_AUTH_FAILED )
ret = MBEDTLS_ERR_CIPHER_AUTH_FAILED;
return( ret );
}
#endif /* MBEDTLS_CHACHAPOLY_C */
return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE );
}
