1: /*
2: * Routines to support checksumming of bytes.
3: *
4: * Copyright (C) 1996 Andrew Tridgell
5: * Copyright (C) 1996 Paul Mackerras
6: * Copyright (C) 2004-2015 Wayne Davison
7: *
8: * This program is free software; you can redistribute it and/or modify
9: * it under the terms of the GNU General Public License as published by
10: * the Free Software Foundation; either version 3 of the License, or
11: * (at your option) any later version.
12: *
13: * This program is distributed in the hope that it will be useful,
14: * but WITHOUT ANY WARRANTY; without even the implied warranty of
15: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16: * GNU General Public License for more details.
17: *
18: * You should have received a copy of the GNU General Public License along
19: * with this program; if not, visit the http://fsf.org website.
20: */
21:
22: #include "rsync.h"
23:
24: extern int checksum_seed;
25: extern int protocol_version;
26: extern int proper_seed_order;
27:
28: /*
29: a simple 32 bit checksum that can be upadted from either end
30: (inspired by Mark Adler's Adler-32 checksum)
31: */
32: uint32 get_checksum1(char *buf1, int32 len)
33: {
34: int32 i;
35: uint32 s1, s2;
36: schar *buf = (schar *)buf1;
37:
38: s1 = s2 = 0;
39: for (i = 0; i < (len-4); i+=4) {
40: s2 += 4*(s1 + buf[i]) + 3*buf[i+1] + 2*buf[i+2] + buf[i+3] +
41: 10*CHAR_OFFSET;
42: s1 += (buf[i+0] + buf[i+1] + buf[i+2] + buf[i+3] + 4*CHAR_OFFSET);
43: }
44: for (; i < len; i++) {
45: s1 += (buf[i]+CHAR_OFFSET); s2 += s1;
46: }
47: return (s1 & 0xffff) + (s2 << 16);
48: }
49:
50:
51: void get_checksum2(char *buf, int32 len, char *sum)
52: {
53: md_context m;
54:
55: if (protocol_version >= 30) {
56: uchar seedbuf[4];
57: md5_begin(&m);
58: if (proper_seed_order) {
59: if (checksum_seed) {
60: SIVALu(seedbuf, 0, checksum_seed);
61: md5_update(&m, seedbuf, 4);
62: }
63: md5_update(&m, (uchar *)buf, len);
64: } else {
65: md5_update(&m, (uchar *)buf, len);
66: if (checksum_seed) {
67: SIVALu(seedbuf, 0, checksum_seed);
68: md5_update(&m, seedbuf, 4);
69: }
70: }
71: md5_result(&m, (uchar *)sum);
72: } else {
73: int32 i;
74: static char *buf1;
75: static int32 len1;
76:
77: mdfour_begin(&m);
78:
79: if (len > len1) {
80: if (buf1)
81: free(buf1);
82: buf1 = new_array(char, len+4);
83: len1 = len;
84: if (!buf1)
85: out_of_memory("get_checksum2");
86: }
87:
88: memcpy(buf1, buf, len);
89: if (checksum_seed) {
90: SIVAL(buf1,len,checksum_seed);
91: len += 4;
92: }
93:
94: for (i = 0; i + CSUM_CHUNK <= len; i += CSUM_CHUNK)
95: mdfour_update(&m, (uchar *)(buf1+i), CSUM_CHUNK);
96:
97: /*
98: * Prior to version 27 an incorrect MD4 checksum was computed
99: * by failing to call mdfour_tail() for block sizes that
100: * are multiples of 64. This is fixed by calling mdfour_update()
101: * even when there are no more bytes.
102: */
103: if (len - i > 0 || protocol_version >= 27)
104: mdfour_update(&m, (uchar *)(buf1+i), len-i);
105:
106: mdfour_result(&m, (uchar *)sum);
107: }
108: }
109:
110: void file_checksum(const char *fname, const STRUCT_STAT *st_p, char *sum)
111: {
112: struct map_struct *buf;
113: OFF_T i, len = st_p->st_size;
114: md_context m;
115: int32 remainder;
116: int fd;
117:
118: memset(sum, 0, MAX_DIGEST_LEN);
119:
120: fd = do_open(fname, O_RDONLY, 0);
121: if (fd == -1)
122: return;
123:
124: buf = map_file(fd, len, MAX_MAP_SIZE, CSUM_CHUNK);
125:
126: if (protocol_version >= 30) {
127: md5_begin(&m);
128:
129: for (i = 0; i + CSUM_CHUNK <= len; i += CSUM_CHUNK) {
130: md5_update(&m, (uchar *)map_ptr(buf, i, CSUM_CHUNK),
131: CSUM_CHUNK);
132: }
133:
134: remainder = (int32)(len - i);
135: if (remainder > 0)
136: md5_update(&m, (uchar *)map_ptr(buf, i, remainder), remainder);
137:
138: md5_result(&m, (uchar *)sum);
139: } else {
140: mdfour_begin(&m);
141:
142: for (i = 0; i + CSUM_CHUNK <= len; i += CSUM_CHUNK) {
143: mdfour_update(&m, (uchar *)map_ptr(buf, i, CSUM_CHUNK),
144: CSUM_CHUNK);
145: }
146:
147: /* Prior to version 27 an incorrect MD4 checksum was computed
148: * by failing to call mdfour_tail() for block sizes that
149: * are multiples of 64. This is fixed by calling mdfour_update()
150: * even when there are no more bytes. */
151: remainder = (int32)(len - i);
152: if (remainder > 0 || protocol_version >= 27)
153: mdfour_update(&m, (uchar *)map_ptr(buf, i, remainder), remainder);
154:
155: mdfour_result(&m, (uchar *)sum);
156: }
157:
158: close(fd);
159: unmap_file(buf);
160: }
161:
162: static int32 sumresidue;
163: static md_context md;
164:
165: void sum_init(int seed)
166: {
167: char s[4];
168:
169: if (protocol_version >= 30)
170: md5_begin(&md);
171: else {
172: mdfour_begin(&md);
173: sumresidue = 0;
174: SIVAL(s, 0, seed);
175: sum_update(s, 4);
176: }
177: }
178:
179: /**
180: * Feed data into an MD4 accumulator, md. The results may be
181: * retrieved using sum_end(). md is used for different purposes at
182: * different points during execution.
183: *
184: * @todo Perhaps get rid of md and just pass in the address each time.
185: * Very slightly clearer and slower.
186: **/
187: void sum_update(const char *p, int32 len)
188: {
189: if (protocol_version >= 30) {
190: md5_update(&md, (uchar *)p, len);
191: return;
192: }
193:
194: if (len + sumresidue < CSUM_CHUNK) {
195: memcpy(md.buffer + sumresidue, p, len);
196: sumresidue += len;
197: return;
198: }
199:
200: if (sumresidue) {
201: int32 i = CSUM_CHUNK - sumresidue;
202: memcpy(md.buffer + sumresidue, p, i);
203: mdfour_update(&md, (uchar *)md.buffer, CSUM_CHUNK);
204: len -= i;
205: p += i;
206: }
207:
208: while (len >= CSUM_CHUNK) {
209: mdfour_update(&md, (uchar *)p, CSUM_CHUNK);
210: len -= CSUM_CHUNK;
211: p += CSUM_CHUNK;
212: }
213:
214: sumresidue = len;
215: if (sumresidue)
216: memcpy(md.buffer, p, sumresidue);
217: }
218:
219: int sum_end(char *sum)
220: {
221: if (protocol_version >= 30) {
222: md5_result(&md, (uchar *)sum);
223: return MD5_DIGEST_LEN;
224: }
225:
226: if (sumresidue || protocol_version >= 27)
227: mdfour_update(&md, (uchar *)md.buffer, sumresidue);
228:
229: mdfour_result(&md, (uchar *)sum);
230:
231: return MD4_DIGEST_LEN;
232: }
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