138 lines
3.8 KiB
C
138 lines
3.8 KiB
C
/*
|
|
* Copyright (c) 1999 Kungliga Tekniska Högskolan
|
|
* (Royal Institute of Technology, Stockholm, Sweden).
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
*
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
*
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
*
|
|
* 3. Neither the name of KTH nor the names of its contributors may be
|
|
* used to endorse or promote products derived from this software without
|
|
* specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY KTH AND ITS CONTRIBUTORS ``AS IS'' AND ANY
|
|
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
|
|
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL KTH OR ITS CONTRIBUTORS BE
|
|
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
|
|
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
|
|
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
|
|
* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
|
|
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
|
|
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
|
|
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */
|
|
|
|
#include "krb5_locl.h"
|
|
|
|
RCSID("$Id: n-fold.c 22190 2007-12-06 16:24:22Z lha $");
|
|
|
|
static krb5_error_code
|
|
rr13(unsigned char *buf, size_t len)
|
|
{
|
|
unsigned char *tmp;
|
|
int bytes = (len + 7) / 8;
|
|
int i;
|
|
if(len == 0)
|
|
return 0;
|
|
{
|
|
const int bits = 13 % len;
|
|
const int lbit = len % 8;
|
|
|
|
tmp = malloc(bytes);
|
|
if (tmp == NULL)
|
|
return ENOMEM;
|
|
memcpy(tmp, buf, bytes);
|
|
if(lbit) {
|
|
/* pad final byte with inital bits */
|
|
tmp[bytes - 1] &= 0xff << (8 - lbit);
|
|
for(i = lbit; i < 8; i += len)
|
|
tmp[bytes - 1] |= buf[0] >> i;
|
|
}
|
|
for(i = 0; i < bytes; i++) {
|
|
int bb;
|
|
int b1, s1, b2, s2;
|
|
/* calculate first bit position of this byte */
|
|
bb = 8 * i - bits;
|
|
while(bb < 0)
|
|
bb += len;
|
|
/* byte offset and shift count */
|
|
b1 = bb / 8;
|
|
s1 = bb % 8;
|
|
|
|
if(bb + 8 > bytes * 8)
|
|
/* watch for wraparound */
|
|
s2 = (len + 8 - s1) % 8;
|
|
else
|
|
s2 = 8 - s1;
|
|
b2 = (b1 + 1) % bytes;
|
|
buf[i] = (tmp[b1] << s1) | (tmp[b2] >> s2);
|
|
}
|
|
free(tmp);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/* Add `b' to `a', both being one's complement numbers. */
|
|
static void
|
|
add1(unsigned char *a, unsigned char *b, size_t len)
|
|
{
|
|
int i;
|
|
int carry = 0;
|
|
for(i = len - 1; i >= 0; i--){
|
|
int x = a[i] + b[i] + carry;
|
|
carry = x > 0xff;
|
|
a[i] = x & 0xff;
|
|
}
|
|
for(i = len - 1; carry && i >= 0; i--){
|
|
int x = a[i] + carry;
|
|
carry = x > 0xff;
|
|
a[i] = x & 0xff;
|
|
}
|
|
}
|
|
|
|
krb5_error_code KRB5_LIB_FUNCTION
|
|
_krb5_n_fold(const void *str, size_t len, void *key, size_t size)
|
|
{
|
|
/* if len < size we need at most N * len bytes, ie < 2 * size;
|
|
if len > size we need at most 2 * len */
|
|
krb5_error_code ret = 0;
|
|
size_t maxlen = 2 * max(size, len);
|
|
size_t l = 0;
|
|
unsigned char *tmp = malloc(maxlen);
|
|
unsigned char *buf = malloc(len);
|
|
|
|
if (tmp == NULL || buf == NULL)
|
|
return ENOMEM;
|
|
|
|
memcpy(buf, str, len);
|
|
memset(key, 0, size);
|
|
do {
|
|
memcpy(tmp + l, buf, len);
|
|
l += len;
|
|
ret = rr13(buf, len * 8);
|
|
if (ret)
|
|
goto out;
|
|
while(l >= size) {
|
|
add1(key, tmp, size);
|
|
l -= size;
|
|
if(l == 0)
|
|
break;
|
|
memmove(tmp, tmp + size, l);
|
|
}
|
|
} while(l != 0);
|
|
out:
|
|
memset(buf, 0, len);
|
|
free(buf);
|
|
memset(tmp, 0, maxlen);
|
|
free(tmp);
|
|
return ret;
|
|
}
|