1/*
2 * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
3 * Use is subject to license terms.
4 */
5
6#pragma ident	"%Z%%M%	%I%	%E% SMI"
7
8/*
9 * lib/crypto/crc32/crc.c
10 *
11 * Copyright 1990, 2002 by the Massachusetts Institute of Technology.
12 * All Rights Reserved.
13 *
14 * Export of this software from the United States of America may
15 *   require a specific license from the United States Government.
16 *   It is the responsibility of any person or organization contemplating
17 *   export to obtain such a license before exporting.
18 *
19 * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
20 * distribute this software and its documentation for any purpose and
21 * without fee is hereby granted, provided that the above copyright
22 * notice appear in all copies and that both that copyright notice and
23 * this permission notice appear in supporting documentation, and that
24 * the name of M.I.T. not be used in advertising or publicity pertaining
25 * to distribution of the software without specific, written prior
26 * permission.  M.I.T. makes no representations about the suitability of
27 * this software for any purpose.  It is provided "as is" without express
28 * or implied warranty.
29 *
30 *
31 * CRC-32/AUTODIN-II routines
32 */
33
34#include <k5-int.h>
35#include <crc-32.h>
36
37/* This table and block of comments are taken from code labeled: */
38/*
39 * Copyright (C) 1986 Gary S. Brown.  You may use this program, or
40 * code or tables extracted from it, as desired without restriction.
41 */
42
43/* First, the polynomial itself and its table of feedback terms.  The  */
44/* polynomial is                                                       */
45/* X^32+X^26+X^23+X^22+X^16+X^12+X^11+X^10+X^8+X^7+X^5+X^4+X^2+X^1+X^0 */
46/* Note that we take it "backwards" and put the highest-order term in  */
47/* the lowest-order bit.  The X^32 term is "implied"; the LSB is the   */
48/* X^31 term, etc.  The X^0 term (usually shown as "+1") results in    */
49/* the MSB being 1.                                                    */
50
51/* Note that the usual hardware shift register implementation, which   */
52/* is what we're using (we're merely optimizing it by doing eight-bit  */
53/* chunks at a time) shifts bits into the lowest-order term.  In our   */
54/* implementation, that means shifting towards the right.  Why do we   */
55/* do it this way?  Because the calculated CRC must be transmitted in  */
56/* order from highest-order term to lowest-order term.  UARTs transmit */
57/* characters in order from LSB to MSB.  By storing the CRC this way,  */
58/* we hand it to the UART in the order low-byte to high-byte; the UART */
59/* sends each low-bit to hight-bit; and the result is transmission bit */
60/* by bit from highest- to lowest-order term without requiring any bit */
61/* shuffling on our part.  Reception works similarly.                  */
62
63/* The feedback terms table consists of 256, 32-bit entries.  Notes:   */
64/*                                                                     */
65/*  1. The table can be generated at runtime if desired; code to do so */
66/*     is shown later.  It might not be obvious, but the feedback      */
67/*     terms simply represent the results of eight shift/xor opera-    */
68/*     tions for all combinations of data and CRC register values.     */
69/*                                                                     */
70/*  2. The CRC accumulation logic is the same for all CRC polynomials, */
71/*     be they sixteen or thirty-two bits wide.  You simply choose the */
72/*     appropriate table.  Alternatively, because the table can be     */
73/*     generated at runtime, you can start by generating the table for */
74/*     the polynomial in question and use exactly the same "updcrc",   */
75/*     if your application needn't simultaneously handle two CRC       */
76/*     polynomials.  (Note, however, that XMODEM is strange.)          */
77/*                                                                     */
78/*  3. For 16-bit CRCs, the table entries need be only 16 bits wide;   */
79/*     of course, 32-bit entries work OK if the high 16 bits are zero. */
80/*                                                                     */
81/*  4. The values must be right-shifted by eight bits by the "updcrc"  */
82/*     logic; the shift must be unsigned (bring in zeroes).  On some   */
83/*     hardware you could probably optimize the shift in assembler by  */
84/*     using byte-swap instructions.                                   */
85
86static uint32_t const crc_table[256] = {
87    0x00000000, 0x77073096, 0xee0e612c, 0x990951ba,
88    0x076dc419, 0x706af48f, 0xe963a535, 0x9e6495a3,
89    0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
90    0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91,
91    0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de,
92    0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
93    0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec,
94    0x14015c4f, 0x63066cd9, 0xfa0f3d63, 0x8d080df5,
95    0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
96    0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b,
97    0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940,
98    0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
99    0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116,
100    0x21b4f4b5, 0x56b3c423, 0xcfba9599, 0xb8bda50f,
101    0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
102    0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d,
103    0x76dc4190, 0x01db7106, 0x98d220bc, 0xefd5102a,
104    0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
105    0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818,
106    0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01,
107    0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
108    0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457,
109    0x65b0d9c6, 0x12b7e950, 0x8bbeb8ea, 0xfcb9887c,
110    0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
111    0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2,
112    0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb,
113    0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
114    0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9,
115    0x5005713c, 0x270241aa, 0xbe0b1010, 0xc90c2086,
116    0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
117    0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4,
118    0x59b33d17, 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad,
119    0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
120    0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683,
121    0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8,
122    0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
123    0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe,
124    0xf762575d, 0x806567cb, 0x196c3671, 0x6e6b06e7,
125    0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
126    0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5,
127    0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252,
128    0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
129    0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60,
130    0xdf60efc3, 0xa867df55, 0x316e8eef, 0x4669be79,
131    0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
132    0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f,
133    0xc5ba3bbe, 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04,
134    0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
135    0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a,
136    0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713,
137    0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
138    0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21,
139    0x86d3d2d4, 0xf1d4e242, 0x68ddb3f8, 0x1fda836e,
140    0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
141    0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c,
142    0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45,
143    0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
144    0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db,
145    0xaed16a4a, 0xd9d65adc, 0x40df0b66, 0x37d83bf0,
146    0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
147    0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6,
148    0xbad03605, 0xcdd70693, 0x54de5729, 0x23d967bf,
149    0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
150    0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
151    };
152
153/* Windows needs to these prototypes for crc32_cksumtable_entry below */
154
155static krb5_error_code
156crc32_sum_func (
157	krb5_const krb5_pointer in,
158	krb5_const size_t in_length,
159	krb5_const krb5_pointer seed,
160	krb5_const size_t seed_length,
161	krb5_checksum *outcksum);
162
163static krb5_error_code
164crc32_verify_func (
165	krb5_const krb5_checksum *cksum,
166	krb5_const krb5_pointer in,
167	krb5_const size_t in_length,
168	krb5_const krb5_pointer seed,
169	krb5_const size_t seed_length);
170
171/*ARGSUSED*/
172static krb5_error_code
173crc32_sum_func(in, in_length, seed, seed_length, outcksum)
174    krb5_const krb5_pointer in;
175    krb5_const size_t in_length;
176    krb5_const krb5_pointer seed;
177    krb5_const size_t seed_length;
178    krb5_checksum *outcksum;
179{
180    register u_char *data;
181    register u_long c = 0;
182    register int idx;
183    size_t i;
184
185    if (outcksum->length < CRC32_CKSUM_LENGTH)
186	return KRB5_BAD_MSIZE;
187
188    data = (u_char *)in;
189    for (i = 0; i < in_length; i++) {
190	idx = (int) (data[i] ^ c);
191	idx &= 0xff;
192	c >>= 8;
193	c ^= (u_long) crc_table[idx];
194    }
195    /* c now holds the result */
196    outcksum->checksum_type = CKSUMTYPE_CRC32;
197    outcksum->length = CRC32_CKSUM_LENGTH;
198    outcksum->contents[0] = (krb5_octet) (c & 0xff);
199    outcksum->contents[1] = (krb5_octet) ((c >> 8) & 0xff);
200    outcksum->contents[2] = (krb5_octet) ((c >> 16) & 0xff);
201    outcksum->contents[3] = (krb5_octet) ((c >> 24) & 0xff);
202    return 0;
203}
204
205/*ARGSUSED*/
206static krb5_error_code
207crc32_verify_func(cksum, in, in_length, seed, seed_length)
208    krb5_const krb5_checksum *cksum;
209    krb5_const krb5_pointer in;
210    krb5_const size_t in_length;
211    krb5_const krb5_pointer seed;
212    krb5_const size_t seed_length;
213{
214    register u_char *data;
215    register u_long c = 0;
216    register int idx;
217    size_t i;
218    krb5_error_code	retval;
219
220    retval = 0;
221    if (cksum->checksum_type == CKSUMTYPE_CRC32) {
222	if (cksum->length == CRC32_CKSUM_LENGTH) {
223	    data = (u_char *)in;
224	    for (i = 0; i < in_length; i++) {
225		idx = (int) (data[i] ^ c);
226		idx &= 0xff;
227		c >>= 8;
228		c ^= (u_long) crc_table[idx];
229	    }
230	    if ((cksum->contents[0] != (krb5_octet) (c & 0xff)) ||
231		(cksum->contents[1] != (krb5_octet) ((c >> 8) & 0xff)) ||
232		(cksum->contents[2] != (krb5_octet) ((c >> 16) & 0xff)) ||
233		(cksum->contents[3] != (krb5_octet) ((c >> 24) & 0xff)))
234		retval = KRB5KRB_AP_ERR_BAD_INTEGRITY;
235	}
236	else
237	    retval = KRB5KRB_AP_ERR_BAD_INTEGRITY;
238    }
239    else
240	retval = KRB5KRB_AP_ERR_INAPP_CKSUM;
241    return(retval);
242}
243
244