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1 : /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
2 : /*
3 : * This file is part of the LibreOffice project.
4 : *
5 : * This Source Code Form is subject to the terms of the Mozilla Public
6 : * License, v. 2.0. If a copy of the MPL was not distributed with this
7 : * file, You can obtain one at http://mozilla.org/MPL/2.0/.
8 : *
9 : * This file incorporates work covered by the following license notice:
10 : *
11 : * Licensed to the Apache Software Foundation (ASF) under one or more
12 : * contributor license agreements. See the NOTICE file distributed
13 : * with this work for additional information regarding copyright
14 : * ownership. The ASF licenses this file to you under the Apache
15 : * License, Version 2.0 (the "License"); you may not use this file
16 : * except in compliance with the License. You may obtain a copy of
17 : * the License at http://www.apache.org/licenses/LICENSE-2.0 .
18 : */
19 :
20 :
21 : #include "md5.hxx"
22 :
23 : #include <cstddef>
24 : #include <stdio.h>
25 :
26 : #include <rtl/strbuf.hxx>
27 :
28 : #ifdef WNT
29 : #define FILE_OPEN_READ "rb"
30 : #else
31 : #define FILE_OPEN_READ "r"
32 : #endif
33 :
34 : // Extended calc_md5_checksum to recognize Windows executables and libraries. To
35 : // create the same md5 checksum for a (code/data) identical file it ignores a different
36 : // date and header checksum. Please see crashrep/source/win32/soreport.cpp
37 : // where the same method is also used. The crash reporter uses the MD5
38 : // checksums to transfer them to the crash database. You have to make sure that both
39 : // methods use the same algorithm otherwise there could be problems with stack reports.
40 :
41 0 : void normalize_pe_image(sal_uInt8* buffer, size_t nBufferSize)
42 : {
43 0 : const int OFFSET_PE_OFFSET = 0x3c;
44 0 : const int OFFSET_COFF_TIMEDATESTAMP = 4;
45 0 : const int PE_SIGNATURE_SIZE = 4;
46 0 : const int COFFHEADER_SIZE = 20;
47 0 : const int OFFSET_PE_OPTIONALHEADER_CHECKSUM = 64;
48 :
49 : // Check the header part of the file buffer
50 0 : if (buffer[0] == sal_uInt8('M') && buffer[1] == sal_uInt8('Z'))
51 : {
52 0 : unsigned long PEHeaderOffset = (long)buffer[OFFSET_PE_OFFSET];
53 0 : if (PEHeaderOffset < nBufferSize-4)
54 : {
55 0 : if ( buffer[PEHeaderOffset+0] == sal_uInt8('P') &&
56 0 : buffer[PEHeaderOffset+1] == sal_uInt8('E') &&
57 0 : buffer[PEHeaderOffset+2] == 0 &&
58 0 : buffer[PEHeaderOffset+3] == 0 )
59 : {
60 0 : PEHeaderOffset += PE_SIGNATURE_SIZE;
61 0 : if (PEHeaderOffset+OFFSET_COFF_TIMEDATESTAMP < nBufferSize-4)
62 : {
63 : // Set timedatestamp and checksum fields to a normalized
64 : // value to enforce the same MD5 checksum for identical
65 : // Windows executables/libraries.
66 0 : buffer[PEHeaderOffset+OFFSET_COFF_TIMEDATESTAMP+0] = 0;
67 0 : buffer[PEHeaderOffset+OFFSET_COFF_TIMEDATESTAMP+1] = 0;
68 0 : buffer[PEHeaderOffset+OFFSET_COFF_TIMEDATESTAMP+2] = 0;
69 0 : buffer[PEHeaderOffset+OFFSET_COFF_TIMEDATESTAMP+3] = 0;
70 : }
71 :
72 0 : if (PEHeaderOffset+COFFHEADER_SIZE+OFFSET_PE_OPTIONALHEADER_CHECKSUM < nBufferSize-4)
73 : {
74 : // Set checksum to a normalized value
75 0 : buffer[PEHeaderOffset+COFFHEADER_SIZE+OFFSET_PE_OPTIONALHEADER_CHECKSUM] = 0;
76 0 : buffer[PEHeaderOffset+COFFHEADER_SIZE+OFFSET_PE_OPTIONALHEADER_CHECKSUM+1] = 0;
77 0 : buffer[PEHeaderOffset+COFFHEADER_SIZE+OFFSET_PE_OPTIONALHEADER_CHECKSUM+2] = 0;
78 0 : buffer[PEHeaderOffset+COFFHEADER_SIZE+OFFSET_PE_OPTIONALHEADER_CHECKSUM+3] = 0;
79 : }
80 : }
81 : }
82 : }
83 0 : }
84 :
85 0 : rtlDigestError calc_md5_checksum(const char *filename, rtl::OString &rChecksum)
86 : {
87 0 : const size_t BUFFER_SIZE = 0x1000;
88 0 : const size_t MINIMAL_SIZE = 512;
89 :
90 : sal_uInt8 checksum[RTL_DIGEST_LENGTH_MD5];
91 0 : rtlDigestError error = rtl_Digest_E_None;
92 0 : rtl::OStringBuffer aChecksumBuf;
93 :
94 0 : FILE *fp = fopen( filename, FILE_OPEN_READ );
95 :
96 0 : if ( fp )
97 : {
98 0 : rtlDigest digest = rtl_digest_createMD5();
99 :
100 0 : if ( digest )
101 : {
102 : size_t nBytesRead;
103 : sal_uInt8 buffer[BUFFER_SIZE];
104 0 : bool bHeader(true);
105 :
106 0 : while ( rtl_Digest_E_None == error &&
107 : 0 != (nBytesRead = fread( buffer, 1, sizeof(buffer), fp )) )
108 : {
109 0 : if (bHeader)
110 : {
111 0 : bHeader = false;
112 0 : if (nBytesRead >= MINIMAL_SIZE && buffer[0] == sal_uInt8('M') && buffer[1] == sal_uInt8('Z') )
113 0 : normalize_pe_image(buffer, nBytesRead);
114 : }
115 :
116 0 : error = rtl_digest_updateMD5( digest, buffer, nBytesRead );
117 : }
118 :
119 0 : if ( rtl_Digest_E_None == error )
120 : {
121 0 : error = rtl_digest_getMD5( digest, checksum, sizeof(checksum) );
122 : }
123 :
124 0 : rtl_digest_destroyMD5( digest );
125 :
126 0 : for ( std::size_t i = 0; i < sizeof(checksum); i++ )
127 : {
128 0 : if ( checksum[i] < 16 )
129 0 : aChecksumBuf.append('0');
130 0 : aChecksumBuf.append(static_cast<sal_Int32>(checksum[i]), 16);
131 : }
132 : }
133 :
134 0 : fclose( fp );
135 : }
136 : else
137 0 : error = rtl_Digest_E_Unknown;
138 :
139 0 : rChecksum = aChecksumBuf.makeStringAndClear();
140 :
141 0 : return error;
142 : }
143 :
144 : /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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