1 // Copyright 2014 PDFium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
6
7 #include "core/fxcrt/cfx_checksumcontext.h"
8
9 #include "core/fdrm/crypto/fx_crypt.h"
10 #include "core/fxcrt/fx_stream.h"
11 #include "core/fxcrt/xml/cfx_saxreaderhandler.h"
12 #include "third_party/base/ptr_util.h"
13
14 namespace {
15
16 struct FX_BASE64DATA {
17 uint32_t data1 : 2;
18 uint32_t data2 : 6;
19 uint32_t data3 : 4;
20 uint32_t data4 : 4;
21 uint32_t data5 : 6;
22 uint32_t data6 : 2;
23 uint32_t data7 : 8;
24 };
25
26 const char g_FXBase64EncoderMap[64] = {
27 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
28 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
29 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
30 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
31 '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/',
32 };
33
Base64EncodePiece(const FX_BASE64DATA & src,int32_t iBytes,char dst[4])34 void Base64EncodePiece(const FX_BASE64DATA& src, int32_t iBytes, char dst[4]) {
35 dst[0] = g_FXBase64EncoderMap[src.data2];
36 uint32_t b = src.data1 << 4;
37 if (iBytes > 1) {
38 b |= src.data4;
39 }
40 dst[1] = g_FXBase64EncoderMap[b];
41 if (iBytes > 1) {
42 b = src.data3 << 2;
43 if (iBytes > 2) {
44 b |= src.data6;
45 }
46 dst[2] = g_FXBase64EncoderMap[b];
47 if (iBytes > 2) {
48 dst[3] = g_FXBase64EncoderMap[src.data5];
49 } else {
50 dst[3] = '=';
51 }
52 } else {
53 dst[2] = dst[3] = '=';
54 }
55 }
56
Base64EncodeA(const uint8_t * pSrc,int32_t iSrcLen,char * pDst)57 int32_t Base64EncodeA(const uint8_t* pSrc, int32_t iSrcLen, char* pDst) {
58 ASSERT(pSrc);
59 if (iSrcLen < 1) {
60 return 0;
61 }
62 if (!pDst) {
63 int32_t iDstLen = iSrcLen / 3 * 4;
64 if ((iSrcLen % 3) != 0) {
65 iDstLen += 4;
66 }
67 return iDstLen;
68 }
69 FX_BASE64DATA srcData;
70 int32_t iBytes = 3;
71 char* pDstEnd = pDst;
72 while (iSrcLen > 0) {
73 if (iSrcLen > 2) {
74 ((uint8_t*)&srcData)[0] = *pSrc++;
75 ((uint8_t*)&srcData)[1] = *pSrc++;
76 ((uint8_t*)&srcData)[2] = *pSrc++;
77 iSrcLen -= 3;
78 } else {
79 *((uint32_t*)&srcData) = 0;
80 ((uint8_t*)&srcData)[0] = *pSrc++;
81 if (iSrcLen > 1) {
82 ((uint8_t*)&srcData)[1] = *pSrc++;
83 }
84 iBytes = iSrcLen;
85 iSrcLen = 0;
86 }
87 Base64EncodePiece(srcData, iBytes, pDstEnd);
88 pDstEnd += 4;
89 }
90 return pDstEnd - pDst;
91 }
92
93 } // namespace
94
CFX_ChecksumContext()95 CFX_ChecksumContext::CFX_ChecksumContext() {}
96
~CFX_ChecksumContext()97 CFX_ChecksumContext::~CFX_ChecksumContext() {}
98
StartChecksum()99 void CFX_ChecksumContext::StartChecksum() {
100 FinishChecksum();
101 m_pByteContext = pdfium::MakeUnique<CRYPT_sha1_context>();
102 CRYPT_SHA1Start(m_pByteContext.get());
103 m_bsChecksum.clear();
104 m_pSAXReader = pdfium::MakeUnique<CFX_SAXReader>();
105 }
106
UpdateChecksum(const RetainPtr<IFX_SeekableReadStream> & pSrcFile,FX_FILESIZE offset,size_t size)107 bool CFX_ChecksumContext::UpdateChecksum(
108 const RetainPtr<IFX_SeekableReadStream>& pSrcFile,
109 FX_FILESIZE offset,
110 size_t size) {
111 if (!m_pSAXReader || !pSrcFile)
112 return false;
113
114 if (size < 1)
115 size = pSrcFile->GetSize();
116
117 CFX_SAXReaderHandler handler(this);
118 m_pSAXReader->SetHandler(&handler);
119 if (m_pSAXReader->StartParse(
120 pSrcFile, (uint32_t)offset, (uint32_t)size,
121 CFX_SaxParseMode_NotSkipSpace | CFX_SaxParseMode_NotConvert_amp |
122 CFX_SaxParseMode_NotConvert_lt | CFX_SaxParseMode_NotConvert_gt |
123 CFX_SaxParseMode_NotConvert_sharp) < 0) {
124 return false;
125 }
126 return m_pSAXReader->ContinueParse() > 99;
127 }
128
FinishChecksum()129 void CFX_ChecksumContext::FinishChecksum() {
130 m_pSAXReader.reset();
131 if (m_pByteContext) {
132 uint8_t digest[20];
133 memset(digest, 0, 20);
134 CRYPT_SHA1Finish(m_pByteContext.get(), digest);
135 int32_t nLen = Base64EncodeA(digest, 20, nullptr);
136 char* pBuffer = m_bsChecksum.GetBuffer(nLen);
137 Base64EncodeA(digest, 20, pBuffer);
138 m_bsChecksum.ReleaseBuffer(nLen);
139 m_pByteContext.reset();
140 }
141 }
142
GetChecksum() const143 ByteString CFX_ChecksumContext::GetChecksum() const {
144 return m_bsChecksum;
145 }
146
Update(const ByteStringView & bsText)147 void CFX_ChecksumContext::Update(const ByteStringView& bsText) {
148 if (!m_pByteContext)
149 return;
150
151 CRYPT_SHA1Update(m_pByteContext.get(), bsText.raw_str(), bsText.GetLength());
152 }
153