diff options
Diffstat (limited to 'source4/heimdal/lib/krb5/n-fold.c')
| -rw-r--r-- | source4/heimdal/lib/krb5/n-fold.c | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/source4/heimdal/lib/krb5/n-fold.c b/source4/heimdal/lib/krb5/n-fold.c new file mode 100644 index 0000000000..691e95eb86 --- /dev/null +++ b/source4/heimdal/lib/krb5/n-fold.c @@ -0,0 +1,126 @@ +/* + * 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,v 1.7 2004/05/25 21:35:31 lha Exp $"); + +static void +rr13(unsigned char *buf, size_t len) +{ + unsigned char *tmp; + int bytes = (len + 7) / 8; + int i; + if(len == 0) + return; + { + const int bits = 13 % len; + const int lbit = len % 8; + + tmp = malloc(bytes); + 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); + } +} + +/* Add `b' to `a', both beeing 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; + } +} + +void 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 */ + size_t maxlen = 2 * max(size, len); + size_t l = 0; + unsigned char *tmp = malloc(maxlen); + unsigned char *buf = malloc(len); + + memcpy(buf, str, len); + memset(key, 0, size); + do { + memcpy(tmp + l, buf, len); + l += len; + rr13(buf, len * 8); + while(l >= size) { + add1(key, tmp, size); + l -= size; + if(l == 0) + break; + memmove(tmp, tmp + size, l); + } + } while(l != 0); + memset(buf, 0, len); + free(buf); + memset(tmp, 0, maxlen); + free(tmp); +} |