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) 1995-1997, 1999-2001, 2005-2006, 2008-2023 Free Software
4 Foundation, Inc.
5 This file is part of the GNU C Library.
6
7 This file is free software: you can redistribute it and/or modify
8 it under the terms of the GNU Lesser General Public License as
9 published by the Free Software Foundation; either version 2.1 of the
10 License, or (at your option) any later version.
11
12 This file is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU Lesser General Public License for more details.
16
17 You should have received a copy of the GNU Lesser General Public License
18 along with this program. If not, see <https://www.gnu.org/licenses/>. */
19
20 /* Written by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1995. */
21
22 #include <config.h>
23
24 /* Specification. */
25 #if HAVE_OPENSSL_MD5
26 # define GL_OPENSSL_INLINE _GL_EXTERN_INLINE
27 #endif
28 #include "md5.h"
29
30 #include <stdlib.h>
31
32 #if USE_UNLOCKED_IO
33 # include "unlocked-io.h"
34 #endif
35
36 #include "af_alg.h"
37
38 #ifdef _LIBC
39 # include <endian.h>
40 # if __BYTE_ORDER == __BIG_ENDIAN
41 # define WORDS_BIGENDIAN 1
42 # endif
43 /* We need to keep the namespace clean so define the MD5 function
44 protected using leading __ . */
45 # define md5_init_ctx __md5_init_ctx
46 # define md5_process_block __md5_process_block
47 # define md5_process_bytes __md5_process_bytes
48 # define md5_finish_ctx __md5_finish_ctx
49 # define md5_stream __md5_stream
50 #endif
51
52 #define BLOCKSIZE 32768
53 #if BLOCKSIZE % 64 != 0
54 # error "invalid BLOCKSIZE"
55 #endif
56
57 /* Compute MD5 message digest for bytes read from STREAM. The
58 resulting message digest number will be written into the 16 bytes
59 beginning at RESBLOCK. */
60 int
61 md5_stream (FILE *stream, void *resblock)
62 {
63 switch (afalg_stream (stream, "md5", resblock, MD5_DIGEST_SIZE))
64 {
65 case 0: return 0;
66 case -EIO: return 1;
67 }
68
69 char *buffer = malloc (BLOCKSIZE + 72);
70 if (!buffer)
71 return 1;
72
73 struct md5_ctx ctx;
74 md5_init_ctx (&ctx);
75 size_t sum;
76
77 /* Iterate over full file contents. */
78 while (1)
79 {
80 /* We read the file in blocks of BLOCKSIZE bytes. One call of the
81 computation function processes the whole buffer so that with the
82 next round of the loop another block can be read. */
83 size_t n;
84 sum = 0;
85
86 /* Read block. Take care for partial reads. */
87 while (1)
88 {
89 /* Either process a partial fread() from this loop,
90 or the fread() in afalg_stream may have gotten EOF.
91 We need to avoid a subsequent fread() as EOF may
92 not be sticky. For details of such systems, see:
93 https://sourceware.org/bugzilla/show_bug.cgi?id=1190 */
94 if (feof (stream))
95 goto process_partial_block;
96
97 n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream);
98
99 sum += n;
100
101 if (sum == BLOCKSIZE)
102 break;
103
104 if (n == 0)
105 {
106 /* Check for the error flag IFF N == 0, so that we don't
107 exit the loop after a partial read due to e.g., EAGAIN
108 or EWOULDBLOCK. */
109 if (ferror (stream))
110 {
111 free (buffer);
112 return 1;
113 }
114 goto process_partial_block;
115 }
116 }
117
118 /* Process buffer with BLOCKSIZE bytes. Note that
119 BLOCKSIZE % 64 == 0
120 */
121 md5_process_block (buffer, BLOCKSIZE, &ctx);
122 }
123
124 process_partial_block:
125
126 /* Process any remaining bytes. */
127 if (sum > 0)
128 md5_process_bytes (buffer, sum, &ctx);
129
130 /* Construct result in desired memory. */
131 md5_finish_ctx (&ctx, resblock);
132 free (buffer);
133 return 0;
134 }
135
136 /*
137 * Hey Emacs!
138 * Local Variables:
139 * coding: utf-8
140 * End:
141 */