/* Decrypt one block using CBC. */
static krb5_error_code
cbc_decr(krb5_key key, const krb5_data *ivec, krb5_crypto_iov *data,
size_t num_data)
{
int ret = 0, olen = BLOCK_SIZE;
unsigned char iblock[BLOCK_SIZE], oblock[BLOCK_SIZE];
EVP_CIPHER_CTX *ctx;
struct iov_cursor cursor;
ctx = EVP_CIPHER_CTX_new();
if (ctx == NULL)
return ENOMEM;
ret = EVP_DecryptInit_ex(ctx, map_mode(key->keyblock.length),
NULL, key->keyblock.contents, (ivec) ? (unsigned char*)ivec->data : NULL);
if (ret == 0) {
EVP_CIPHER_CTX_free(ctx);
return KRB5_CRYPTO_INTERNAL;
}
k5_iov_cursor_init(&cursor, data, num_data, BLOCK_SIZE, FALSE);
k5_iov_cursor_get(&cursor, iblock);
EVP_CIPHER_CTX_set_padding(ctx,0);
ret = EVP_DecryptUpdate(ctx, oblock, &olen, iblock, BLOCK_SIZE);
if (ret == 1)
k5_iov_cursor_put(&cursor, oblock);
EVP_CIPHER_CTX_free(ctx);
zap(iblock, BLOCK_SIZE);
zap(oblock, BLOCK_SIZE);
return (ret == 1) ? 0 : KRB5_CRYPTO_INTERNAL;
}
/*
* k5_des3_encrypt: Encrypt data buffer using 3DES.
*
* @key DES key (with odd parity)
* @ivec Initialization Vector
* @data Input/Output buffer (in-place encryption, block-by-block)
* @num_data Number of blocks
*
* Returns 0 on success, krb5_error_code on error
*/
static krb5_error_code
k5_des3_encrypt(krb5_key key, const krb5_data *ivec, krb5_crypto_iov *data,
size_t num_data)
{
int ret;
Des3 des3;
unsigned char iv[DES_BLOCK_SIZE];
unsigned char iblock[DES_BLOCK_SIZE];
unsigned char oblock[DES_BLOCK_SIZE];
//struct iov_block_state input_pos, output_pos;
struct iov_cursor cursor;
krb5_boolean empty;
ret = validate(key, ivec, data, num_data, &empty);
if (ret != 0 || empty)
return ret;
memset(iv, 0, sizeof(iv));
/* Check if IV exists and is the correct size */
if (ivec && ivec->data) {
if (ivec->length != sizeof(iv))
return KRB5_CRYPTO_INTERNAL;
memcpy(iv, ivec->data, ivec->length);
}
Des3_SetKey(&des3, key->keyblock.contents, iv, DES_ENCRYPTION);
k5_iov_cursor_init(&cursor, data, num_data, DES_BLOCK_SIZE, FALSE);
for (;;) {
if (!k5_iov_cursor_get(&cursor, iblock))
break;
Des3_CbcEncrypt(&des3, oblock, iblock, DES_BLOCK_SIZE);
k5_iov_cursor_put(&cursor, oblock);
}
if (ivec != NULL)
memcpy(ivec->data, oblock, DES_BLOCK_SIZE);
zap(iv, sizeof(iv));
zap(iblock, sizeof(iblock));
zap(oblock, sizeof(oblock));
return 0;
}
static krb5_error_code
cts_decr(krb5_key key, const krb5_data *ivec, krb5_crypto_iov *data,
size_t num_data, size_t dlen)
{
int ret = 0;
size_t size = 0;
unsigned char *oblock = NULL;
unsigned char *dbuf = NULL;
unsigned char iv_cts[IV_CTS_BUF_SIZE];
struct iov_cursor cursor;
AES_KEY deck;
memset(iv_cts,0,sizeof(iv_cts));
if (ivec && ivec->data) {
if (ivec->length != sizeof(iv_cts))
return KRB5_CRYPTO_INTERNAL;
memcpy(iv_cts, ivec->data,ivec->length);
}
oblock = OPENSSL_malloc(dlen);
if (!oblock)
return ENOMEM;
dbuf = OPENSSL_malloc(dlen);
if (!dbuf) {
OPENSSL_free(oblock);
return ENOMEM;
}
AES_set_decrypt_key(key->keyblock.contents,
NUM_BITS * key->keyblock.length, &deck);
k5_iov_cursor_init(&cursor, data, num_data, dlen, FALSE);
k5_iov_cursor_get(&cursor, dbuf);
size = CRYPTO_cts128_decrypt((unsigned char *)dbuf, oblock,
dlen, &deck,
iv_cts, (cbc128_f)AES_cbc_encrypt);
if (size <= 0)
ret = KRB5_CRYPTO_INTERNAL;
else
k5_iov_cursor_put(&cursor, oblock);
if (!ret && ivec && ivec->data)
memcpy(ivec->data, iv_cts, sizeof(iv_cts));
zap(oblock, dlen);
zap(dbuf, dlen);
OPENSSL_free(oblock);
OPENSSL_free(dbuf);
return ret;
}
