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/*
* $Source$
* $Author$
*
* Copyright 1985, 1986, 1987, 1988, 1990, 1991 by the Massachusetts Institute
* of Technology.
* All Rights Reserved.
*
* These routines perform encryption and decryption using the DES
* private key algorithm, or else a subset of it -- fewer inner loops.
* (AUTH_DES_ITER defaults to 16, may be less.)
*
* Under U.S. law, this software may not be exported outside the US
* without license from the U.S. Commerce department.
*
* These routines form the library interface to the DES facilities.
*
* Originally written 8/85 by Steve Miller, MIT Project Athena.
*
* Export of this software from the United States of America is assumed
* to require a specific license from the United States Government.
* It is the responsibility of any person or organization contemplating
* export to obtain such a license before exporting.
*
* WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
* distribute this software and its documentation for any purpose and
* without fee is hereby granted, provided that the above copyright
* notice appear in all copies and that both that copyright notice and
* this permission notice appear in supporting documentation, and that
* the name of M.I.T. not be used in advertising or publicity pertaining
* to distribution of the software without specific, written prior
* permission. M.I.T. makes no representations about the suitability of
* this software for any purpose. It is provided "as is" without express
* or implied warranty.
*
*
*/
/*
* These routines were extracted out of enc_dec.c because they will
* drag in the kerberos library, if someone references mit_des_cbc_encrypt,
* even no kerberos routines are called
*/
#if !defined(lint) && !defined(SABER)
static char rcsid_enc_dec_c[] =
"$Id$";
#endif /* !lint & !SABER */
#include <krb5/krb5.h>
#include <krb5/ext-proto.h>
#include <krb5/los-proto.h>
#include <krb5/crc-32.h>
#include "des_int.h"
#ifdef DEBUG
#include <stdio.h>
extern int mit_des_debug;
#endif
/*
encrypts "size" bytes at "in", storing result in "out".
"eblock" points to an encrypt block which has been initialized
by process_key().
"out" must be preallocated by the caller to contain sufficient
storage to hold the output; the macro krb5_encrypt_size() can
be used to compute this size.
returns: errors
*/
static krb5_error_code
mit_des_encrypt_f(DECLARG(krb5_const_pointer, in),
DECLARG(krb5_pointer, out),
DECLARG(const size_t, size),
DECLARG(krb5_encrypt_block *, key),
DECLARG(krb5_pointer, ivec))
OLDDECLARG(krb5_const_pointer, in)
OLDDECLARG(krb5_pointer, out)
OLDDECLARG(const size_t, size)
OLDDECLARG(krb5_encrypt_block *, key)
OLDDECLARG(krb5_pointer, ivec)
{
krb5_octet *iv;
if ( ivec == 0 )
iv = key->key->contents;
else
iv = (krb5_octet *)ivec;
return (mit_des_cbc_encrypt((krb5_octet *)in,
(krb5_octet *)out,
size,
(struct mit_des_ks_struct *)key->priv,
iv,
MIT_DES_ENCRYPT));
}
/*
decrypts "size" bytes at "in", storing result in "out".
"eblock" points to an encrypt block which has been initialized
by process_key().
"out" must be preallocated by the caller to contain sufficient
storage to hold the output; this is guaranteed to be no more than
the input size.
returns: errors
*/
static krb5_error_code
mit_des_decrypt_f(DECLARG(krb5_const_pointer, in),
DECLARG(krb5_pointer, out),
DECLARG(const size_t, size),
DECLARG(krb5_encrypt_block *, key),
DECLARG(krb5_pointer, ivec))
OLDDECLARG(krb5_const_pointer, in)
OLDDECLARG(krb5_pointer, out)
OLDDECLARG(const size_t, size)
OLDDECLARG(krb5_encrypt_block *, key)
OLDDECLARG(krb5_pointer, ivec)
{
krb5_octet *iv;
if ( ivec == 0 )
iv = key->key->contents;
else
iv = (krb5_octet *)ivec;
return (mit_des_cbc_encrypt ((krb5_octet *)in,
(krb5_octet *)out,
size,
(struct mit_des_ks_struct *)key->priv,
iv,
MIT_DES_DECRYPT));
}
krb5_error_code mit_des_encrypt_func(DECLARG(krb5_const_pointer, in),
DECLARG(krb5_pointer, out),
DECLARG(const size_t, size),
DECLARG(krb5_encrypt_block *, key),
DECLARG(krb5_pointer, ivec))
OLDDECLARG(krb5_const_pointer, in)
OLDDECLARG(krb5_pointer, out)
OLDDECLARG(const size_t, size)
OLDDECLARG(krb5_encrypt_block *, key)
OLDDECLARG(krb5_pointer, ivec)
{
krb5_checksum cksum;
krb5_octet contents[CRC32_CKSUM_LENGTH];
int sumsize;
krb5_error_code retval;
/* if ( size < sizeof(mit_des_cblock) )
return KRB5_BAD_MSIZE; */
/* caller passes data size, and saves room for the padding. */
/* format of ciphertext, per RFC is:
+-----------+----------+-------------+-----+
|confounder | check | msg-seq | pad |
+-----------+----------+-------------+-----+
our confounder is 8 bytes (one cblock);
our checksum is CRC32_CKSUM_LENGTH
*/
sumsize = krb5_roundup(size+CRC32_CKSUM_LENGTH+sizeof(mit_des_cblock),
sizeof(mit_des_cblock));
/* assemble crypto input into the output area, then encrypt in place. */
memset((char *)out, 0, sumsize);
/* put in the confounder */
if (retval = krb5_random_confounder(sizeof(mit_des_cblock), out))
return retval;
memcpy((char *)out+sizeof(mit_des_cblock)+CRC32_CKSUM_LENGTH, (char *)in,
size);
cksum.contents = contents;
if (retval = krb5_calculate_checksum(CKSUMTYPE_CRC32,
(krb5_pointer) out,
sumsize,
(krb5_pointer)key->key->contents,
sizeof(mit_des_cblock),
&cksum))
return retval;
memcpy((char *)out+sizeof(mit_des_cblock), (char *)contents,
CRC32_CKSUM_LENGTH);
/* We depend here on the ability of this DES implementation to
encrypt plaintext to ciphertext in-place. */
return (mit_des_encrypt_f(out, out, sumsize, key, ivec));
}
krb5_error_code mit_des_decrypt_func(DECLARG(krb5_const_pointer, in),
DECLARG(krb5_pointer, out),
DECLARG(const size_t, size),
DECLARG(krb5_encrypt_block *, key),
DECLARG(krb5_pointer, ivec))
OLDDECLARG(krb5_const_pointer, in)
OLDDECLARG(krb5_pointer, out)
OLDDECLARG(const size_t, size)
OLDDECLARG(krb5_encrypt_block *, key)
OLDDECLARG(krb5_pointer, ivec)
{
krb5_checksum cksum;
krb5_octet contents_prd[CRC32_CKSUM_LENGTH];
krb5_octet contents_get[CRC32_CKSUM_LENGTH];
char *p;
krb5_error_code retval;
if ( size < 2*sizeof(mit_des_cblock) )
return KRB5_BAD_MSIZE;
if (retval = mit_des_decrypt_f(in, out, size, key, ivec))
return retval;
cksum.contents = contents_prd;
p = (char *)out + sizeof(mit_des_cblock);
memcpy((char *)contents_get, p, CRC32_CKSUM_LENGTH);
memset(p, 0, CRC32_CKSUM_LENGTH);
if (retval = krb5_calculate_checksum(CKSUMTYPE_CRC32,
out,
size,
(krb5_pointer)key->key->contents,
sizeof(mit_des_cblock),
&cksum))
return retval;
if (memcmp((char *)contents_get, (char *)contents_prd, CRC32_CKSUM_LENGTH) )
return KRB5KRB_AP_ERR_BAD_INTEGRITY;
memcpy((char *)out, (char *)out +
sizeof(mit_des_cblock) + CRC32_CKSUM_LENGTH,
size - sizeof(mit_des_cblock) + CRC32_CKSUM_LENGTH);
return 0;
}
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