| 1 | /* |
| 2 | * Routines to support checksumming of bytes. |
| 3 | * |
| 4 | * Copyright (C) 1996 Andrew Tridgell |
| 5 | * Copyright (C) 1996 Paul Mackerras |
| 6 | * Copyright (C) 2004-2007 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 | |
| 27 | int csum_length = SHORT_SUM_LENGTH; /* initial value */ |
| 28 | |
| 29 | /* |
| 30 | a simple 32 bit checksum that can be upadted from either end |
| 31 | (inspired by Mark Adler's Adler-32 checksum) |
| 32 | */ |
| 33 | uint32 get_checksum1(char *buf1, int32 len) |
| 34 | { |
| 35 | int32 i; |
| 36 | uint32 s1, s2; |
| 37 | schar *buf = (schar *)buf1; |
| 38 | |
| 39 | s1 = s2 = 0; |
| 40 | for (i = 0; i < (len-4); i+=4) { |
| 41 | s2 += 4*(s1 + buf[i]) + 3*buf[i+1] + 2*buf[i+2] + buf[i+3] + |
| 42 | 10*CHAR_OFFSET; |
| 43 | s1 += (buf[i+0] + buf[i+1] + buf[i+2] + buf[i+3] + 4*CHAR_OFFSET); |
| 44 | } |
| 45 | for (; i < len; i++) { |
| 46 | s1 += (buf[i]+CHAR_OFFSET); s2 += s1; |
| 47 | } |
| 48 | return (s1 & 0xffff) + (s2 << 16); |
| 49 | } |
| 50 | |
| 51 | |
| 52 | void get_checksum2(char *buf, int32 len, char *sum) |
| 53 | { |
| 54 | md_context m; |
| 55 | |
| 56 | if (protocol_version >= 30) { |
| 57 | uchar seedbuf[4]; |
| 58 | md5_begin(&m); |
| 59 | md5_update(&m, (uchar *)buf, len); |
| 60 | if (checksum_seed) { |
| 61 | SIVAL(seedbuf, 0, checksum_seed); |
| 62 | md5_update(&m, seedbuf, 4); |
| 63 | } |
| 64 | md5_result(&m, (uchar *)sum); |
| 65 | } else { |
| 66 | int32 i; |
| 67 | static char *buf1; |
| 68 | static int32 len1; |
| 69 | |
| 70 | mdfour_begin(&m); |
| 71 | |
| 72 | if (len > len1) { |
| 73 | if (buf1) |
| 74 | free(buf1); |
| 75 | buf1 = new_array(char, len+4); |
| 76 | len1 = len; |
| 77 | if (!buf1) |
| 78 | out_of_memory("get_checksum2"); |
| 79 | } |
| 80 | |
| 81 | memcpy(buf1, buf, len); |
| 82 | if (checksum_seed) { |
| 83 | SIVAL(buf1,len,checksum_seed); |
| 84 | len += 4; |
| 85 | } |
| 86 | |
| 87 | for (i = 0; i + CSUM_CHUNK <= len; i += CSUM_CHUNK) |
| 88 | mdfour_update(&m, (uchar *)(buf1+i), CSUM_CHUNK); |
| 89 | |
| 90 | /* |
| 91 | * Prior to version 27 an incorrect MD4 checksum was computed |
| 92 | * by failing to call mdfour_tail() for block sizes that |
| 93 | * are multiples of 64. This is fixed by calling mdfour_update() |
| 94 | * even when there are no more bytes. |
| 95 | */ |
| 96 | if (len - i > 0 || protocol_version >= 27) |
| 97 | mdfour_update(&m, (uchar *)(buf1+i), len-i); |
| 98 | |
| 99 | mdfour_result(&m, (uchar *)sum); |
| 100 | } |
| 101 | } |
| 102 | |
| 103 | void file_checksum(char *fname, char *sum, OFF_T size) |
| 104 | { |
| 105 | struct map_struct *buf; |
| 106 | OFF_T i, len = size; |
| 107 | md_context m; |
| 108 | int32 remainder; |
| 109 | int fd; |
| 110 | |
| 111 | memset(sum, 0, MAX_DIGEST_LEN); |
| 112 | |
| 113 | fd = do_open(fname, O_RDONLY, 0); |
| 114 | if (fd == -1) |
| 115 | return; |
| 116 | |
| 117 | buf = map_file(fd, size, MAX_MAP_SIZE, CSUM_CHUNK); |
| 118 | |
| 119 | if (protocol_version >= 30) { |
| 120 | md5_begin(&m); |
| 121 | |
| 122 | for (i = 0; i + CSUM_CHUNK <= len; i += CSUM_CHUNK) { |
| 123 | md5_update(&m, (uchar *)map_ptr(buf, i, CSUM_CHUNK), |
| 124 | CSUM_CHUNK); |
| 125 | } |
| 126 | |
| 127 | remainder = (int32)(len - i); |
| 128 | if (remainder > 0) |
| 129 | md5_update(&m, (uchar *)map_ptr(buf, i, remainder), remainder); |
| 130 | |
| 131 | md5_result(&m, (uchar *)sum); |
| 132 | } else { |
| 133 | mdfour_begin(&m); |
| 134 | |
| 135 | for (i = 0; i + CSUM_CHUNK <= len; i += CSUM_CHUNK) { |
| 136 | mdfour_update(&m, (uchar *)map_ptr(buf, i, CSUM_CHUNK), |
| 137 | CSUM_CHUNK); |
| 138 | } |
| 139 | |
| 140 | /* Prior to version 27 an incorrect MD4 checksum was computed |
| 141 | * by failing to call mdfour_tail() for block sizes that |
| 142 | * are multiples of 64. This is fixed by calling mdfour_update() |
| 143 | * even when there are no more bytes. */ |
| 144 | remainder = (int32)(len - i); |
| 145 | if (remainder > 0 || protocol_version >= 27) |
| 146 | mdfour_update(&m, (uchar *)map_ptr(buf, i, remainder), remainder); |
| 147 | |
| 148 | mdfour_result(&m, (uchar *)sum); |
| 149 | } |
| 150 | |
| 151 | close(fd); |
| 152 | unmap_file(buf); |
| 153 | } |
| 154 | |
| 155 | static int32 sumresidue; |
| 156 | static md_context md; |
| 157 | |
| 158 | void sum_init(int seed) |
| 159 | { |
| 160 | char s[4]; |
| 161 | |
| 162 | if (protocol_version >= 30) |
| 163 | md5_begin(&md); |
| 164 | else { |
| 165 | mdfour_begin(&md); |
| 166 | sumresidue = 0; |
| 167 | SIVAL(s, 0, seed); |
| 168 | sum_update(s, 4); |
| 169 | } |
| 170 | } |
| 171 | |
| 172 | /** |
| 173 | * Feed data into an MD4 accumulator, md. The results may be |
| 174 | * retrieved using sum_end(). md is used for different purposes at |
| 175 | * different points during execution. |
| 176 | * |
| 177 | * @todo Perhaps get rid of md and just pass in the address each time. |
| 178 | * Very slightly clearer and slower. |
| 179 | **/ |
| 180 | void sum_update(const char *p, int32 len) |
| 181 | { |
| 182 | if (protocol_version >= 30) { |
| 183 | md5_update(&md, (uchar *)p, len); |
| 184 | return; |
| 185 | } |
| 186 | |
| 187 | if (len + sumresidue < CSUM_CHUNK) { |
| 188 | memcpy(md.buffer + sumresidue, p, len); |
| 189 | sumresidue += len; |
| 190 | return; |
| 191 | } |
| 192 | |
| 193 | if (sumresidue) { |
| 194 | int32 i = CSUM_CHUNK - sumresidue; |
| 195 | memcpy(md.buffer + sumresidue, p, i); |
| 196 | mdfour_update(&md, (uchar *)md.buffer, CSUM_CHUNK); |
| 197 | len -= i; |
| 198 | p += i; |
| 199 | } |
| 200 | |
| 201 | while (len >= CSUM_CHUNK) { |
| 202 | mdfour_update(&md, (uchar *)p, CSUM_CHUNK); |
| 203 | len -= CSUM_CHUNK; |
| 204 | p += CSUM_CHUNK; |
| 205 | } |
| 206 | |
| 207 | sumresidue = len; |
| 208 | if (sumresidue) |
| 209 | memcpy(md.buffer, p, sumresidue); |
| 210 | } |
| 211 | |
| 212 | int sum_end(char *sum) |
| 213 | { |
| 214 | if (protocol_version >= 30) { |
| 215 | md5_result(&md, (uchar *)sum); |
| 216 | return MD5_DIGEST_LEN; |
| 217 | } |
| 218 | |
| 219 | if (sumresidue || protocol_version >= 27) |
| 220 | mdfour_update(&md, (uchar *)md.buffer, sumresidue); |
| 221 | |
| 222 | mdfour_result(&md, (uchar *)sum); |
| 223 | |
| 224 | return MD4_DIGEST_LEN; |
| 225 | } |