1b528cefcSMark Murray /*
2*ae771770SStanislav Sedov * Copyright (c) 1999 Kungliga Tekniska Högskolan
3b528cefcSMark Murray * (Royal Institute of Technology, Stockholm, Sweden).
4b528cefcSMark Murray * All rights reserved.
5b528cefcSMark Murray *
6b528cefcSMark Murray * Redistribution and use in source and binary forms, with or without
7b528cefcSMark Murray * modification, are permitted provided that the following conditions
8b528cefcSMark Murray * are met:
9b528cefcSMark Murray *
10b528cefcSMark Murray * 1. Redistributions of source code must retain the above copyright
11b528cefcSMark Murray * notice, this list of conditions and the following disclaimer.
12b528cefcSMark Murray *
13b528cefcSMark Murray * 2. Redistributions in binary form must reproduce the above copyright
14b528cefcSMark Murray * notice, this list of conditions and the following disclaimer in the
15b528cefcSMark Murray * documentation and/or other materials provided with the distribution.
16b528cefcSMark Murray *
17b528cefcSMark Murray * 3. Neither the name of KTH nor the names of its contributors may be
18b528cefcSMark Murray * used to endorse or promote products derived from this software without
19b528cefcSMark Murray * specific prior written permission.
20b528cefcSMark Murray *
21b528cefcSMark Murray * THIS SOFTWARE IS PROVIDED BY KTH AND ITS CONTRIBUTORS ``AS IS'' AND ANY
22b528cefcSMark Murray * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23b528cefcSMark Murray * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
24b528cefcSMark Murray * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL KTH OR ITS CONTRIBUTORS BE
25b528cefcSMark Murray * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
26b528cefcSMark Murray * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
27b528cefcSMark Murray * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
28b528cefcSMark Murray * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
29b528cefcSMark Murray * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
30b528cefcSMark Murray * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
31b528cefcSMark Murray * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */
32b528cefcSMark Murray
33b528cefcSMark Murray #include "krb5_locl.h"
34b528cefcSMark Murray
35c19800e8SDoug Rabson static krb5_error_code
rr13(unsigned char * buf,size_t len)36b528cefcSMark Murray rr13(unsigned char *buf, size_t len)
37b528cefcSMark Murray {
38b528cefcSMark Murray unsigned char *tmp;
39b528cefcSMark Murray int bytes = (len + 7) / 8;
40b528cefcSMark Murray int i;
41b528cefcSMark Murray if(len == 0)
42c19800e8SDoug Rabson return 0;
43b528cefcSMark Murray {
44b528cefcSMark Murray const int bits = 13 % len;
45b528cefcSMark Murray const int lbit = len % 8;
46b528cefcSMark Murray
47b528cefcSMark Murray tmp = malloc(bytes);
48c19800e8SDoug Rabson if (tmp == NULL)
49c19800e8SDoug Rabson return ENOMEM;
50b528cefcSMark Murray memcpy(tmp, buf, bytes);
51b528cefcSMark Murray if(lbit) {
52b528cefcSMark Murray /* pad final byte with inital bits */
53b528cefcSMark Murray tmp[bytes - 1] &= 0xff << (8 - lbit);
54b528cefcSMark Murray for(i = lbit; i < 8; i += len)
55b528cefcSMark Murray tmp[bytes - 1] |= buf[0] >> i;
56b528cefcSMark Murray }
57b528cefcSMark Murray for(i = 0; i < bytes; i++) {
58b528cefcSMark Murray int bb;
59b528cefcSMark Murray int b1, s1, b2, s2;
60b528cefcSMark Murray /* calculate first bit position of this byte */
61b528cefcSMark Murray bb = 8 * i - bits;
62b528cefcSMark Murray while(bb < 0)
63b528cefcSMark Murray bb += len;
64b528cefcSMark Murray /* byte offset and shift count */
65b528cefcSMark Murray b1 = bb / 8;
66b528cefcSMark Murray s1 = bb % 8;
67b528cefcSMark Murray
68b528cefcSMark Murray if(bb + 8 > bytes * 8)
69b528cefcSMark Murray /* watch for wraparound */
70b528cefcSMark Murray s2 = (len + 8 - s1) % 8;
71b528cefcSMark Murray else
72b528cefcSMark Murray s2 = 8 - s1;
73b528cefcSMark Murray b2 = (b1 + 1) % bytes;
74b528cefcSMark Murray buf[i] = (tmp[b1] << s1) | (tmp[b2] >> s2);
75b528cefcSMark Murray }
76b528cefcSMark Murray free(tmp);
77b528cefcSMark Murray }
78c19800e8SDoug Rabson return 0;
79b528cefcSMark Murray }
80b528cefcSMark Murray
81c19800e8SDoug Rabson /* Add `b' to `a', both being one's complement numbers. */
82b528cefcSMark Murray static void
add1(unsigned char * a,unsigned char * b,size_t len)83b528cefcSMark Murray add1(unsigned char *a, unsigned char *b, size_t len)
84b528cefcSMark Murray {
85b528cefcSMark Murray int i;
86b528cefcSMark Murray int carry = 0;
87b528cefcSMark Murray for(i = len - 1; i >= 0; i--){
88b528cefcSMark Murray int x = a[i] + b[i] + carry;
89b528cefcSMark Murray carry = x > 0xff;
90b528cefcSMark Murray a[i] = x & 0xff;
91b528cefcSMark Murray }
92b528cefcSMark Murray for(i = len - 1; carry && i >= 0; i--){
93b528cefcSMark Murray int x = a[i] + carry;
94b528cefcSMark Murray carry = x > 0xff;
95b528cefcSMark Murray a[i] = x & 0xff;
96b528cefcSMark Murray }
97b528cefcSMark Murray }
98b528cefcSMark Murray
99*ae771770SStanislav Sedov KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
_krb5_n_fold(const void * str,size_t len,void * key,size_t size)100b528cefcSMark Murray _krb5_n_fold(const void *str, size_t len, void *key, size_t size)
101b528cefcSMark Murray {
102b528cefcSMark Murray /* if len < size we need at most N * len bytes, ie < 2 * size;
103b528cefcSMark Murray if len > size we need at most 2 * len */
104c19800e8SDoug Rabson krb5_error_code ret = 0;
105b528cefcSMark Murray size_t maxlen = 2 * max(size, len);
106b528cefcSMark Murray size_t l = 0;
107b528cefcSMark Murray unsigned char *tmp = malloc(maxlen);
108b528cefcSMark Murray unsigned char *buf = malloc(len);
109b528cefcSMark Murray
110*ae771770SStanislav Sedov if (tmp == NULL || buf == NULL) {
111*ae771770SStanislav Sedov ret = ENOMEM;
112*ae771770SStanislav Sedov goto out;
113*ae771770SStanislav Sedov }
114c19800e8SDoug Rabson
115b528cefcSMark Murray memcpy(buf, str, len);
116b528cefcSMark Murray memset(key, 0, size);
117b528cefcSMark Murray do {
118b528cefcSMark Murray memcpy(tmp + l, buf, len);
119b528cefcSMark Murray l += len;
120c19800e8SDoug Rabson ret = rr13(buf, len * 8);
121c19800e8SDoug Rabson if (ret)
122c19800e8SDoug Rabson goto out;
123b528cefcSMark Murray while(l >= size) {
124b528cefcSMark Murray add1(key, tmp, size);
125b528cefcSMark Murray l -= size;
126b528cefcSMark Murray if(l == 0)
127b528cefcSMark Murray break;
128b528cefcSMark Murray memmove(tmp, tmp + size, l);
129b528cefcSMark Murray }
130b528cefcSMark Murray } while(l != 0);
131c19800e8SDoug Rabson out:
132*ae771770SStanislav Sedov if (buf) {
133b528cefcSMark Murray memset(buf, 0, len);
134b528cefcSMark Murray free(buf);
135*ae771770SStanislav Sedov }
136*ae771770SStanislav Sedov if (tmp) {
137b528cefcSMark Murray memset(tmp, 0, maxlen);
138b528cefcSMark Murray free(tmp);
139*ae771770SStanislav Sedov }
140c19800e8SDoug Rabson return ret;
141b528cefcSMark Murray }
142