void
krb5int_des_cbc_decrypt(const mit_des_cblock *in,
mit_des_cblock *out,
unsigned long length,
const mit_des_key_schedule schedule,
const mit_des_cblock ivec)
{
unsigned DES_INT32 left, right;
const unsigned DES_INT32 *kp;
const unsigned char *ip;
unsigned char *op;
unsigned DES_INT32 ocipherl, ocipherr;
unsigned DES_INT32 cipherl, cipherr;
/*
* Get key pointer here. This won't need to be reinitialized
*/
kp = (const unsigned DES_INT32 *)schedule;
/*
* Decrypting is harder than encrypting because of
* the necessity of remembering a lot more things.
* Should think about this a little more...
*/
if (length <= 0)
return;
/*
* Prime the old cipher with ivec.
*/
ip = ivec;
GET_HALF_BLOCK(ocipherl, ip);
GET_HALF_BLOCK(ocipherr, ip);
/*
* Now do this in earnest until we run out of length.
*/
ip = *in;
op = *out;
for (;;) { /* check done inside loop */
/*
* Read a block from the input into left and
* right. Save this cipher block for later.
*/
GET_HALF_BLOCK(left, ip);
GET_HALF_BLOCK(right, ip);
cipherl = left;
cipherr = right;
/*
* Decrypt this.
*/
DES_DO_DECRYPT(left, right, kp);
/*
* Xor with the old cipher to get plain
* text. Output 8 or less bytes of this.
*/
left ^= ocipherl;
right ^= ocipherr;
if (length > 8) {
length -= 8;
PUT_HALF_BLOCK(left, op);
PUT_HALF_BLOCK(right, op);
/*
* Save current cipher block here
*/
ocipherl = cipherl;
ocipherr = cipherr;
} else {
/*
* Trouble here. Start at end of output,
* work backwards.
*/
op += (int) length;
switch(length) {
case 8:
*(--op) = (unsigned char) (right & 0xff);
case 7:
*(--op) = (unsigned char) ((right >> 8) & 0xff);
case 6:
*(--op) = (unsigned char) ((right >> 16) & 0xff);
case 5:
*(--op) = (unsigned char) ((right >> 24) & 0xff);
case 4:
*(--op) = (unsigned char) (left & 0xff);
case 3:
*(--op) = (unsigned char) ((left >> 8) & 0xff);
case 2:
*(--op) = (unsigned char) ((left >> 16) & 0xff);
case 1:
*(--op) = (unsigned char) ((left >> 24) & 0xff);
break;
}
break; /* we're done */
}
}
}
void
krb5int_des3_cbc_decrypt_iov(krb5_crypto_iov *data,
unsigned long num_data,
const mit_des_key_schedule ks1,
const mit_des_key_schedule ks2,
const mit_des_key_schedule ks3,
mit_des_cblock ivec)
{
unsigned DES_INT32 left, right;
const unsigned DES_INT32 *kp1, *kp2, *kp3;
const unsigned char *ip;
unsigned DES_INT32 ocipherl, ocipherr;
unsigned DES_INT32 cipherl, cipherr;
unsigned char *op;
struct iov_block_state input_pos, output_pos;
unsigned char iblock[MIT_DES_BLOCK_LENGTH];
unsigned char oblock[MIT_DES_BLOCK_LENGTH];
IOV_BLOCK_STATE_INIT(&input_pos);
IOV_BLOCK_STATE_INIT(&output_pos);
/*
* Get key pointer here. This won't need to be reinitialized
*/
kp1 = (const unsigned DES_INT32 *)ks1;
kp2 = (const unsigned DES_INT32 *)ks2;
kp3 = (const unsigned DES_INT32 *)ks3;
/*
* Decrypting is harder than encrypting because of
* the necessity of remembering a lot more things.
* Should think about this a little more...
*/
if (num_data == 0)
return;
/*
* Prime the old cipher with ivec.
*/
if (ivec != NULL)
ip = ivec;
else
ip = mit_des_zeroblock;
GET_HALF_BLOCK(ocipherl, ip);
GET_HALF_BLOCK(ocipherr, ip);
/*
* Now do this in earnest until we run out of length.
*/
for (;;) {
/*
* Read a block from the input into left and
* right. Save this cipher block for later.
*/
if (!krb5int_c_iov_get_block(iblock, MIT_DES_BLOCK_LENGTH, data, num_data, &input_pos))
break;
if (input_pos.iov_pos == num_data)
break;
ip = iblock;
op = oblock;
GET_HALF_BLOCK(left, ip);
GET_HALF_BLOCK(right, ip);
cipherl = left;
cipherr = right;
/*
* Decrypt this.
*/
DES_DO_DECRYPT(left, right, kp3);
DES_DO_ENCRYPT(left, right, kp2);
DES_DO_DECRYPT(left, right, kp1);
/*
* Xor with the old cipher to get plain
* text. Output 8 or less bytes of this.
*/
left ^= ocipherl;
right ^= ocipherr;
PUT_HALF_BLOCK(left, op);
PUT_HALF_BLOCK(right, op);
/*
* Save current cipher block here
*/
ocipherl = cipherl;
ocipherr = cipherr;
krb5int_c_iov_put_block(data, num_data, oblock, MIT_DES_BLOCK_LENGTH, &output_pos);
}
if (ivec != NULL) {
op = ivec;
PUT_HALF_BLOCK(ocipherl,op);
PUT_HALF_BLOCK(ocipherr, op);
}
}
void
krb5int_des3_cbc_encrypt_iov(krb5_crypto_iov *data,
unsigned long num_data,
const mit_des_key_schedule ks1,
const mit_des_key_schedule ks2,
const mit_des_key_schedule ks3,
mit_des_cblock ivec)
{
unsigned DES_INT32 left, right;
const unsigned DES_INT32 *kp1, *kp2, *kp3;
const unsigned char *ip;
unsigned char *op;
struct iov_block_state input_pos, output_pos;
unsigned char iblock[MIT_DES_BLOCK_LENGTH];
unsigned char oblock[MIT_DES_BLOCK_LENGTH];
IOV_BLOCK_STATE_INIT(&input_pos);
IOV_BLOCK_STATE_INIT(&output_pos);
/*
* Get key pointer here. This won't need to be reinitialized
*/
kp1 = (const unsigned DES_INT32 *)ks1;
kp2 = (const unsigned DES_INT32 *)ks2;
kp3 = (const unsigned DES_INT32 *)ks3;
/*
* Initialize left and right with the contents of the initial
* vector.
*/
if (ivec != NULL)
ip = ivec;
else
ip = mit_des_zeroblock;
GET_HALF_BLOCK(left, ip);
GET_HALF_BLOCK(right, ip);
/*
* Suitably initialized, now work the length down 8 bytes
* at a time.
*/
for (;;) {
unsigned DES_INT32 temp;
ip = iblock;
op = oblock;
if (!krb5int_c_iov_get_block(iblock, MIT_DES_BLOCK_LENGTH, data, num_data, &input_pos))
break;
if (input_pos.iov_pos == num_data)
break;
GET_HALF_BLOCK(temp, ip);
left ^= temp;
GET_HALF_BLOCK(temp, ip);
right ^= temp;
/*
* Encrypt what we have
*/
DES_DO_ENCRYPT(left, right, kp1);
DES_DO_DECRYPT(left, right, kp2);
DES_DO_ENCRYPT(left, right, kp3);
/*
* Copy the results out
*/
PUT_HALF_BLOCK(left, op);
PUT_HALF_BLOCK(right, op);
krb5int_c_iov_put_block(data, num_data, oblock, MIT_DES_BLOCK_LENGTH, &output_pos);
}
if (ivec != NULL)
memcpy(ivec, oblock, MIT_DES_BLOCK_LENGTH);
}
void
krb5int_des_cbc_decrypt(krb5_crypto_iov *data, unsigned long num_data,
const mit_des_key_schedule schedule,
mit_des_cblock ivec)
{
unsigned DES_INT32 left, right;
const unsigned DES_INT32 *kp;
const unsigned char *ip;
unsigned DES_INT32 ocipherl, ocipherr;
unsigned DES_INT32 cipherl, cipherr;
struct iov_block_state input_pos, output_pos;
unsigned char storage[MIT_DES_BLOCK_LENGTH], *block = NULL, *ptr;
IOV_BLOCK_STATE_INIT(&input_pos);
IOV_BLOCK_STATE_INIT(&output_pos);
/* Get key pointer here. This won't need to be reinitialized. */
kp = (const unsigned DES_INT32 *)schedule;
/*
* Decrypting is harder than encrypting because of
* the necessity of remembering a lot more things.
* Should think about this a little more...
*/
/* Prime the old cipher with ivec. */
ip = (ivec != NULL) ? ivec : mit_des_zeroblock;
GET_HALF_BLOCK(ocipherl, ip);
GET_HALF_BLOCK(ocipherr, ip);
/* Work the length down 8 bytes at a time. */
for (;;) {
if (!krb5int_c_iov_get_block_nocopy(storage, MIT_DES_BLOCK_LENGTH,
data, num_data, &input_pos, &ptr))
break;
block = ptr;
/* Split this block into left and right. */
GET_HALF_BLOCK(left, ptr);
GET_HALF_BLOCK(right, ptr);
cipherl = left;
cipherr = right;
/* Decrypt and xor with the old cipher to get plain text. */
DES_DO_DECRYPT(left, right, kp);
left ^= ocipherl;
right ^= ocipherr;
/* Store the encrypted halves back into block. */
ptr = block;
PUT_HALF_BLOCK(left, ptr);
PUT_HALF_BLOCK(right, ptr);
/* Save current cipher block halves. */
ocipherl = cipherl;
ocipherr = cipherr;
krb5int_c_iov_put_block_nocopy(data, num_data, storage,
MIT_DES_BLOCK_LENGTH, &output_pos,
block);
}
if (ivec != NULL && block != NULL) {
ptr = ivec;
PUT_HALF_BLOCK(ocipherl, ptr);
PUT_HALF_BLOCK(ocipherr, ptr);
}
}
