66f4c441e9
o implement add1() using 32 bit ints, this makes _krb5_n_fold() about 5% faster on an amd64 platform. 64 bit ints yield a further improvement but we would need to test the platform to see if they are natively supported. This should yield better performance improvements on big endian machines as we have to byte swap on little endian boxen. o fix two cases where a malloc(3)d pointer may be dereferenced before we test that it is not NULL.
151 lines
4.0 KiB
C
151 lines
4.0 KiB
C
/*
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* Copyright (c) 1999 Kungliga Tekniska Högskolan
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* (Royal Institute of Technology, Stockholm, Sweden).
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* 3. Neither the name of KTH nor the names of its contributors may be
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* used to endorse or promote products derived from this software without
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* specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY KTH AND ITS CONTRIBUTORS ``AS IS'' AND ANY
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* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL KTH OR ITS CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
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* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */
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#include "krb5_locl.h"
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static void
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rr13(uint8_t *dst1, uint8_t *dst2, uint8_t *src, size_t len)
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{
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int bytes = (len + 7) / 8;
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int i;
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const int bits = 13 % len;
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for (i = 0; i < bytes; i++) {
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int bb;
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int b1, s1, b2, s2;
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/* calculate first bit position of this byte */
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bb = 8 * i - bits;
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while(bb < 0)
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bb += len;
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/* byte offset and shift count */
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b1 = bb / 8;
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s1 = bb % 8;
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if (bb + 8 > bytes * 8)
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/* watch for wraparound */
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s2 = (len + 8 - s1) % 8;
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else
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s2 = 8 - s1;
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b2 = (b1 + 1) % bytes;
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dst1[i] = (src[b1] << s1) | (src[b2] >> s2);
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dst2[i] = dst1[i];
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}
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return;
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}
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/*
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* Add `b' to `a', both being one's complement numbers.
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* This function assumes that inputs *a, *b are aligned
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* to 4 bytes.
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*/
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static void
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add1(uint8_t *a, uint8_t *b, size_t len)
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{
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int i;
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int carry = 0;
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uint32_t x;
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uint32_t left, right;
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for (i = len - 1; (i+1) % 4; i--) {
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x = a[i] + b[i] + carry;
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carry = x > 0xff;
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a[i] = x & 0xff;
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}
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for (i = len / 4 - 1; i >= 0; i--) {
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left = ntohl(((uint32_t *)a)[i]);
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right = ntohl(((uint32_t *)b)[i]);
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x = left + right + carry;
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carry = x < left || x < right;
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((uint32_t *)a)[i] = x;
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}
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for (i = len - 1; (i+1) % 4; i--) {
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x = a[i] + carry;
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carry = x > 0xff;
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a[i] = x & 0xff;
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}
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for (i = len / 4 - 1; carry && i >= 0; i--) {
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left = ((uint32_t *)a)[i];
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x = left + carry;
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carry = x < left;
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((uint32_t *)a)[i] = x;
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}
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for (i = len / 4 - 1; i >=0; i--)
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((uint32_t *)a)[i] = htonl(((uint32_t *)a)[i]);
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}
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KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
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_krb5_n_fold(const void *str, size_t len, void *key, size_t size)
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{
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/* if len < size we need at most N * len bytes, ie < 2 * size;
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if len > size we need at most 2 * len */
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size_t maxlen = 2 * max(size, len);
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size_t l = 0;
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uint8_t *tmp;
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uint8_t *tmpbuf;
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uint8_t *buf1;
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uint8_t *buf2;
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tmp = malloc(maxlen + 2 * len);
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if (tmp == NULL)
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return ENOMEM;
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buf1 = tmp + maxlen;
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buf2 = tmp + maxlen + len;
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memset(key, 0, size);
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memcpy(buf1, str, len);
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memcpy(tmp, buf1, len);
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do {
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l += len;
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while(l >= size) {
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add1(key, tmp, size);
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l -= size;
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if(l == 0)
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break;
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memmove(tmp, tmp + size, l);
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}
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rr13(tmp + l, buf2, buf1, len * 8);
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tmpbuf = buf1;
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buf1 = buf2;
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buf2 = tmpbuf;
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} while(l != 0);
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memset(tmp, 0, maxlen + 2 * len);
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free(tmp);
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return 0;
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}
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