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/*
* 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"
static void
rr13(uint8_t *dst1, uint8_t *dst2, uint8_t *src, size_t len)
{
int bytes = (len + 7) / 8;
int i;
const int bits = 13 % len;
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;
dst1[i] = (src[b1] << s1) | (src[b2] >> s2);
dst2[i] = dst1[i];
}
return;
}
/*
* Add `b' to `a', both being one's complement numbers.
* This function assumes that inputs *a, *b are aligned
* to 4 bytes.
*/
static void
add1(uint8_t *a, uint8_t *b, size_t len)
{
int i;
int carry = 0;
uint32_t x;
uint32_t left, right;
for (i = len - 1; (i+1) % 4; i--) {
x = a[i] + b[i] + carry;
carry = x > 0xff;
a[i] = x & 0xff;
}
for (i = len / 4 - 1; i >= 0; i--) {
left = ntohl(((uint32_t *)a)[i]);
right = ntohl(((uint32_t *)b)[i]);
x = left + right + carry;
carry = x < left || x < right;
((uint32_t *)a)[i] = x;
}
for (i = len - 1; (i+1) % 4; i--) {
x = a[i] + carry;
carry = x > 0xff;
a[i] = x & 0xff;
}
for (i = len / 4 - 1; carry && i >= 0; i--) {
left = ((uint32_t *)a)[i];
x = left + carry;
carry = x < left;
((uint32_t *)a)[i] = x;
}
for (i = len / 4 - 1; i >=0; i--)
((uint32_t *)a)[i] = htonl(((uint32_t *)a)[i]);
}
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
_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 */
size_t maxlen = 2 * max(size, len);
size_t l = 0;
uint8_t *tmp;
uint8_t *tmpbuf;
uint8_t *buf1;
uint8_t *buf2;
tmp = malloc(maxlen + 2 * len);
if (tmp == NULL)
return ENOMEM;
buf1 = tmp + maxlen;
buf2 = tmp + maxlen + len;
memset(key, 0, size);
memcpy(buf1, str, len);
memcpy(tmp, buf1, len);
do {
l += len;
while(l >= size) {
add1(key, tmp, size);
l -= size;
if(l == 0)
break;
memmove(tmp, tmp + size, l);
}
rr13(tmp + l, buf2, buf1, len * 8);
tmpbuf = buf1;
buf1 = buf2;
buf2 = tmpbuf;
} while(l != 0);
memset(tmp, 0, maxlen + 2 * len);
free(tmp);
return 0;
}
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