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1 | /* Functions to compute MD5 message digest of files or memory blocks. | |
2 | according to the definition of MD5 in RFC 1321 from April 1992. | |
3 | Copyright (C) 1995-2019 Free Software Foundation, Inc. | |
4 | This file is part of the GNU C Library. | |
5 | ||
6 | The GNU C Library is free software; you can redistribute it and/or | |
7 | modify it under the terms of the GNU Lesser General Public | |
8 | License as published by the Free Software Foundation; either | |
9 | version 2.1 of the License, or (at your option) any later version. | |
10 | ||
11 | The GNU C Library is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | Lesser General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU Lesser General Public | |
17 | License along with the GNU C Library; if not, see | |
18 | <http://www.gnu.org/licenses/>. */ | |
19 | ||
20 | /* Written by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1995. */ | |
21 | ||
22 | #ifdef HAVE_CONFIG_H | |
23 | # include <config.h> | |
24 | #endif | |
25 | ||
26 | #include <sys/types.h> | |
27 | ||
28 | #if STDC_HEADERS || defined _LIBC | |
29 | # include <stdlib.h> | |
30 | # include <string.h> | |
31 | #else | |
32 | # ifndef HAVE_MEMCPY | |
33 | # define memcpy(d, s, n) (bcopy ((s), (d), (n)), (d)) | |
34 | # endif | |
35 | #endif | |
36 | ||
37 | #include "md5.h" | |
38 | ||
39 | #ifdef _LIBC | |
40 | # include <endian.h> | |
41 | # if __BYTE_ORDER == __BIG_ENDIAN | |
42 | # define WORDS_BIGENDIAN 1 | |
43 | # endif | |
44 | /* We need to keep the namespace clean so define the MD5 function | |
45 | protected using leading __ . */ | |
46 | # define md5_init_ctx __md5_init_ctx | |
47 | # define md5_process_bytes __md5_process_bytes | |
48 | # define md5_finish_ctx __md5_finish_ctx | |
49 | # define md5_read_ctx __md5_read_ctx | |
50 | # define md5_stream __md5_stream | |
51 | # define md5_buffer __md5_buffer | |
52 | #endif | |
53 | ||
54 | #ifdef WORDS_BIGENDIAN | |
55 | # define SWAP(n) \ | |
56 | (((n) << 24) | (((n) & 0xff00) << 8) | (((n) >> 8) & 0xff00) | ((n) >> 24)) | |
57 | #else | |
58 | # define SWAP(n) (n) | |
59 | #endif | |
60 | ||
61 | ||
62 | /* This array contains the bytes used to pad the buffer to the next | |
63 | 64-byte boundary. (RFC 1321, 3.1: Step 1) */ | |
64 | static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ... */ }; | |
65 | ||
66 | ||
67 | /* Initialize structure containing state of computation. | |
68 | (RFC 1321, 3.3: Step 3) */ | |
69 | void | |
70 | md5_init_ctx (struct md5_ctx *ctx) | |
71 | { | |
72 | ctx->A = 0x67452301; | |
73 | ctx->B = 0xefcdab89; | |
74 | ctx->C = 0x98badcfe; | |
75 | ctx->D = 0x10325476; | |
76 | ||
77 | ctx->total[0] = ctx->total[1] = 0; | |
78 | ctx->buflen = 0; | |
79 | } | |
80 | ||
81 | /* Put result from CTX in first 16 bytes following RESBUF. The result | |
82 | must be in little endian byte order. | |
83 | ||
84 | IMPORTANT: On some systems it is required that RESBUF is correctly | |
85 | aligned for a 32 bits value. */ | |
86 | void * | |
87 | md5_read_ctx (const struct md5_ctx *ctx, void *resbuf) | |
88 | { | |
89 | ((md5_uint32 *) resbuf)[0] = SWAP (ctx->A); | |
90 | ((md5_uint32 *) resbuf)[1] = SWAP (ctx->B); | |
91 | ((md5_uint32 *) resbuf)[2] = SWAP (ctx->C); | |
92 | ((md5_uint32 *) resbuf)[3] = SWAP (ctx->D); | |
93 | ||
94 | return resbuf; | |
95 | } | |
96 | ||
97 | /* Process the remaining bytes in the internal buffer and the usual | |
98 | prolog according to the standard and write the result to RESBUF. | |
99 | ||
100 | IMPORTANT: On some systems it is required that RESBUF is correctly | |
101 | aligned for a 32 bits value. */ | |
102 | void * | |
103 | md5_finish_ctx (struct md5_ctx *ctx, void *resbuf) | |
104 | { | |
105 | /* Take yet unprocessed bytes into account. */ | |
106 | md5_uint32 bytes = ctx->buflen; | |
107 | size_t pad; | |
108 | ||
109 | /* Now count remaining bytes. */ | |
110 | ctx->total[0] += bytes; | |
111 | if (ctx->total[0] < bytes) | |
112 | ++ctx->total[1]; | |
113 | ||
114 | pad = bytes >= 56 ? 64 + 56 - bytes : 56 - bytes; | |
115 | memcpy (&ctx->buffer[bytes], fillbuf, pad); | |
116 | ||
117 | /* Put the 64-bit file length in *bits* at the end of the buffer. */ | |
118 | ctx->buffer32[(bytes + pad) / 4] = SWAP (ctx->total[0] << 3); | |
119 | ctx->buffer32[(bytes + pad + 4) / 4] = SWAP ((ctx->total[1] << 3) | |
120 | | (ctx->total[0] >> 29)); | |
121 | ||
122 | /* Process last bytes. */ | |
123 | __md5_process_block (ctx->buffer, bytes + pad + 8, ctx); | |
124 | ||
125 | return md5_read_ctx (ctx, resbuf); | |
126 | } | |
127 | ||
128 | /* Compute MD5 message digest for bytes read from STREAM. The | |
129 | resulting message digest number will be written into the 16 bytes | |
130 | beginning at RESBLOCK. */ | |
131 | int | |
132 | md5_stream (FILE *stream, void *resblock) | |
133 | { | |
134 | /* Important: BLOCKSIZE must be a multiple of 64. */ | |
135 | #define BLOCKSIZE 4096 | |
136 | struct md5_ctx ctx; | |
137 | char buffer[BLOCKSIZE + 72]; | |
138 | size_t sum; | |
139 | ||
140 | /* Initialize the computation context. */ | |
141 | md5_init_ctx (&ctx); | |
142 | ||
143 | /* Iterate over full file contents. */ | |
144 | while (1) | |
145 | { | |
146 | /* We read the file in blocks of BLOCKSIZE bytes. One call of the | |
147 | computation function processes the whole buffer so that with the | |
148 | next round of the loop another block can be read. */ | |
149 | size_t n; | |
150 | sum = 0; | |
151 | ||
152 | /* Read block. Take care for partial reads. */ | |
153 | do | |
154 | { | |
155 | n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream); | |
156 | ||
157 | sum += n; | |
158 | } | |
159 | while (sum < BLOCKSIZE && n != 0); | |
160 | if (n == 0 && ferror (stream)) | |
161 | return 1; | |
162 | ||
163 | /* If end of file is reached, end the loop. */ | |
164 | if (n == 0) | |
165 | break; | |
166 | ||
167 | /* Process buffer with BLOCKSIZE bytes. Note that | |
168 | BLOCKSIZE % 64 == 0 | |
169 | */ | |
170 | __md5_process_block (buffer, BLOCKSIZE, &ctx); | |
171 | } | |
172 | ||
173 | /* Add the last bytes if necessary. */ | |
174 | if (sum > 0) | |
175 | md5_process_bytes (buffer, sum, &ctx); | |
176 | ||
177 | /* Construct result in desired memory. */ | |
178 | md5_finish_ctx (&ctx, resblock); | |
179 | return 0; | |
180 | } | |
181 | ||
182 | /* Compute MD5 message digest for LEN bytes beginning at BUFFER. The | |
183 | result is always in little endian byte order, so that a byte-wise | |
184 | output yields to the wanted ASCII representation of the message | |
185 | digest. */ | |
186 | void * | |
187 | md5_buffer (const char *buffer, size_t len, void *resblock) | |
188 | { | |
189 | struct md5_ctx ctx; | |
190 | ||
191 | /* Initialize the computation context. */ | |
192 | md5_init_ctx (&ctx); | |
193 | ||
194 | /* Process whole buffer but last len % 64 bytes. */ | |
195 | md5_process_bytes (buffer, len, &ctx); | |
196 | ||
197 | /* Put result in desired memory area. */ | |
198 | return md5_finish_ctx (&ctx, resblock); | |
199 | } | |
200 | ||
201 | ||
202 | void | |
203 | md5_process_bytes (const void *buffer, size_t len, struct md5_ctx *ctx) | |
204 | { | |
205 | /* When we already have some bits in our internal buffer concatenate | |
206 | both inputs first. */ | |
207 | if (ctx->buflen != 0) | |
208 | { | |
209 | size_t left_over = ctx->buflen; | |
210 | size_t add = 128 - left_over > len ? len : 128 - left_over; | |
211 | ||
212 | memcpy (&ctx->buffer[left_over], buffer, add); | |
213 | ctx->buflen += add; | |
214 | ||
215 | if (ctx->buflen > 64) | |
216 | { | |
217 | __md5_process_block (ctx->buffer, ctx->buflen & ~63, ctx); | |
218 | ||
219 | ctx->buflen &= 63; | |
220 | /* The regions in the following copy operation cannot overlap. */ | |
221 | memcpy (ctx->buffer, &ctx->buffer[(left_over + add) & ~63], | |
222 | ctx->buflen); | |
223 | } | |
224 | ||
225 | buffer = (const char *) buffer + add; | |
226 | len -= add; | |
227 | } | |
228 | ||
229 | /* Process available complete blocks. */ | |
230 | if (len >= 64) | |
231 | { | |
232 | #if !_STRING_ARCH_unaligned | |
233 | /* To check alignment gcc has an appropriate operator. Other | |
234 | compilers don't. */ | |
235 | # if __GNUC__ >= 2 | |
236 | # define UNALIGNED_P(p) (((md5_uintptr) p) % __alignof__ (md5_uint32) != 0) | |
237 | # else | |
238 | # define UNALIGNED_P(p) (((md5_uintptr) p) % sizeof (md5_uint32) != 0) | |
239 | # endif | |
240 | if (UNALIGNED_P (buffer)) | |
241 | while (len > 64) | |
242 | { | |
243 | __md5_process_block (memcpy (ctx->buffer, buffer, 64), 64, ctx); | |
244 | buffer = (const char *) buffer + 64; | |
245 | len -= 64; | |
246 | } | |
247 | else | |
248 | #endif | |
249 | { | |
250 | __md5_process_block (buffer, len & ~63, ctx); | |
251 | buffer = (const char *) buffer + (len & ~63); | |
252 | len &= 63; | |
253 | } | |
254 | } | |
255 | ||
256 | /* Move remaining bytes in internal buffer. */ | |
257 | if (len > 0) | |
258 | { | |
259 | size_t left_over = ctx->buflen; | |
260 | ||
261 | memcpy (&ctx->buffer[left_over], buffer, len); | |
262 | left_over += len; | |
263 | if (left_over >= 64) | |
264 | { | |
265 | __md5_process_block (ctx->buffer, 64, ctx); | |
266 | left_over -= 64; | |
267 | memcpy (ctx->buffer, &ctx->buffer[64], left_over); | |
268 | } | |
269 | ctx->buflen = left_over; | |
270 | } | |
271 | } | |
272 | ||
273 | #include <md5-block.c> |