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, 2008-2021 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 */