| // Copyright 2016 PDFium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com |
| |
| #include "core/fpdfapi/parser/cpdf_parser.h" |
| |
| #include <algorithm> |
| #include <utility> |
| #include <vector> |
| |
| #include "core/fpdfapi/parser/cpdf_array.h" |
| #include "core/fpdfapi/parser/cpdf_crypto_handler.h" |
| #include "core/fpdfapi/parser/cpdf_dictionary.h" |
| #include "core/fpdfapi/parser/cpdf_document.h" |
| #include "core/fpdfapi/parser/cpdf_linearized_header.h" |
| #include "core/fpdfapi/parser/cpdf_number.h" |
| #include "core/fpdfapi/parser/cpdf_reference.h" |
| #include "core/fpdfapi/parser/cpdf_security_handler.h" |
| #include "core/fpdfapi/parser/cpdf_stream.h" |
| #include "core/fpdfapi/parser/cpdf_stream_acc.h" |
| #include "core/fpdfapi/parser/cpdf_syntax_parser.h" |
| #include "core/fpdfapi/parser/fpdf_parser_utility.h" |
| #include "core/fxcrt/cfx_memorystream.h" |
| #include "core/fxcrt/fx_extension.h" |
| #include "core/fxcrt/fx_safe_types.h" |
| #include "third_party/base/ptr_util.h" |
| #include "third_party/base/stl_util.h" |
| |
| namespace { |
| |
| // A limit on the size of the xref table. Theoretical limits are higher, but |
| // this may be large enough in practice. |
| const int32_t kMaxXRefSize = 1048576; |
| |
| uint32_t GetVarInt(const uint8_t* p, int32_t n) { |
| uint32_t result = 0; |
| for (int32_t i = 0; i < n; ++i) |
| result = result * 256 + p[i]; |
| return result; |
| } |
| |
| int32_t GetStreamNCount(const CFX_RetainPtr<CPDF_StreamAcc>& pObjStream) { |
| return pObjStream->GetDict()->GetIntegerFor("N"); |
| } |
| |
| int32_t GetStreamFirst(const CFX_RetainPtr<CPDF_StreamAcc>& pObjStream) { |
| return pObjStream->GetDict()->GetIntegerFor("First"); |
| } |
| |
| CPDF_Parser::ObjectType GetObjectTypeFromCrossRefStreamType( |
| int cross_ref_stream_type) { |
| switch (cross_ref_stream_type) { |
| case 0: |
| return CPDF_Parser::ObjectType::kFree; |
| case 1: |
| return CPDF_Parser::ObjectType::kNotCompressed; |
| case 2: |
| return CPDF_Parser::ObjectType::kCompressed; |
| default: |
| return CPDF_Parser::ObjectType::kNull; |
| } |
| } |
| |
| } // namespace |
| |
| CPDF_Parser::CPDF_Parser() |
| : m_pSyntax(pdfium::MakeUnique<CPDF_SyntaxParser>()), |
| m_bHasParsed(false), |
| m_bXRefStream(false), |
| m_bVersionUpdated(false), |
| m_FileVersion(0), |
| m_pEncryptDict(nullptr), |
| m_TrailerPos(CPDF_Parser::kInvalidPos), |
| m_dwXrefStartObjNum(0) {} |
| |
| CPDF_Parser::~CPDF_Parser() { |
| ReleaseEncryptHandler(); |
| } |
| |
| uint32_t CPDF_Parser::GetLastObjNum() const { |
| return m_ObjectInfo.empty() ? 0 : m_ObjectInfo.rbegin()->first; |
| } |
| |
| bool CPDF_Parser::IsValidObjectNumber(uint32_t objnum) const { |
| return !m_ObjectInfo.empty() && objnum <= m_ObjectInfo.rbegin()->first; |
| } |
| |
| FX_FILESIZE CPDF_Parser::GetObjectPositionOrZero(uint32_t objnum) const { |
| auto it = m_ObjectInfo.find(objnum); |
| return it != m_ObjectInfo.end() ? it->second.pos : 0; |
| } |
| |
| CPDF_Parser::ObjectType CPDF_Parser::GetObjectType(uint32_t objnum) const { |
| ASSERT(IsValidObjectNumber(objnum)); |
| auto it = m_ObjectInfo.find(objnum); |
| return it != m_ObjectInfo.end() ? it->second.type : ObjectType::kFree; |
| } |
| |
| uint16_t CPDF_Parser::GetObjectGenNum(uint32_t objnum) const { |
| ASSERT(IsValidObjectNumber(objnum)); |
| auto it = m_ObjectInfo.find(objnum); |
| return it != m_ObjectInfo.end() ? it->second.gennum : 0; |
| } |
| |
| bool CPDF_Parser::IsObjectFreeOrNull(uint32_t objnum) const { |
| switch (GetObjectType(objnum)) { |
| case ObjectType::kFree: |
| case ObjectType::kNull: |
| return true; |
| case ObjectType::kNotCompressed: |
| case ObjectType::kCompressed: |
| return false; |
| } |
| ASSERT(false); // NOTREACHED(); |
| return false; |
| } |
| |
| void CPDF_Parser::SetEncryptDictionary(CPDF_Dictionary* pDict) { |
| m_pEncryptDict = pDict; |
| } |
| |
| CFX_RetainPtr<CPDF_CryptoHandler> CPDF_Parser::GetCryptoHandler() const { |
| return m_pSyntax->m_pCryptoHandler; |
| } |
| |
| CFX_RetainPtr<IFX_SeekableReadStream> CPDF_Parser::GetFileAccess() const { |
| return m_pSyntax->GetFileAccess(); |
| } |
| |
| void CPDF_Parser::ShrinkObjectMap(uint32_t objnum) { |
| if (objnum == 0) { |
| m_ObjectInfo.clear(); |
| return; |
| } |
| |
| auto it = m_ObjectInfo.lower_bound(objnum); |
| while (it != m_ObjectInfo.end()) { |
| auto saved_it = it++; |
| m_ObjectInfo.erase(saved_it); |
| } |
| |
| if (!pdfium::ContainsKey(m_ObjectInfo, objnum - 1)) |
| m_ObjectInfo[objnum - 1].pos = 0; |
| } |
| |
| CPDF_Parser::Error CPDF_Parser::StartParse( |
| const CFX_RetainPtr<IFX_SeekableReadStream>& pFileAccess, |
| CPDF_Document* pDocument) { |
| return StartParseInternal(pFileAccess, pDocument, kInvalidHeaderOffset); |
| } |
| |
| CPDF_Parser::Error CPDF_Parser::StartParseInternal( |
| const CFX_RetainPtr<IFX_SeekableReadStream>& pFileAccess, |
| CPDF_Document* pDocument, |
| int32_t iHeaderOffset) { |
| ASSERT(!m_bHasParsed); |
| m_bHasParsed = true; |
| m_bXRefStream = false; |
| m_LastXRefOffset = 0; |
| |
| int32_t offset; |
| if (iHeaderOffset == kInvalidHeaderOffset) { |
| offset = GetHeaderOffset(pFileAccess); |
| if (offset == kInvalidHeaderOffset) |
| return FORMAT_ERROR; |
| } else { |
| offset = iHeaderOffset; |
| } |
| |
| m_pSyntax->InitParser(pFileAccess, offset); |
| |
| uint8_t ch; |
| if (!m_pSyntax->GetCharAt(5, ch)) |
| return FORMAT_ERROR; |
| |
| if (std::isdigit(ch)) |
| m_FileVersion = FXSYS_DecimalCharToInt(static_cast<wchar_t>(ch)) * 10; |
| |
| if (!m_pSyntax->GetCharAt(7, ch)) |
| return FORMAT_ERROR; |
| |
| if (std::isdigit(ch)) |
| m_FileVersion += FXSYS_DecimalCharToInt(static_cast<wchar_t>(ch)); |
| |
| if (m_pSyntax->m_FileLen < m_pSyntax->m_HeaderOffset + 9) |
| return FORMAT_ERROR; |
| |
| m_pSyntax->SetPos(m_pSyntax->m_FileLen - m_pSyntax->m_HeaderOffset - 9); |
| m_pDocument = pDocument; |
| |
| bool bXRefRebuilt = false; |
| if (m_pSyntax->BackwardsSearchToWord("startxref", 4096)) { |
| m_SortedOffset.insert(m_pSyntax->GetPos()); |
| m_pSyntax->GetKeyword(); |
| |
| bool bNumber; |
| CFX_ByteString xrefpos_str = m_pSyntax->GetNextWord(&bNumber); |
| if (!bNumber) |
| return FORMAT_ERROR; |
| |
| m_LastXRefOffset = (FX_FILESIZE)FXSYS_atoi64(xrefpos_str.c_str()); |
| if (!LoadAllCrossRefV4(m_LastXRefOffset) && |
| !LoadAllCrossRefV5(m_LastXRefOffset)) { |
| if (!RebuildCrossRef()) |
| return FORMAT_ERROR; |
| |
| bXRefRebuilt = true; |
| m_LastXRefOffset = 0; |
| } |
| } else { |
| if (!RebuildCrossRef()) |
| return FORMAT_ERROR; |
| |
| bXRefRebuilt = true; |
| } |
| Error eRet = SetEncryptHandler(); |
| if (eRet != SUCCESS) |
| return eRet; |
| |
| m_pDocument->LoadDoc(); |
| if (!m_pDocument->GetRoot() || m_pDocument->GetPageCount() == 0) { |
| if (bXRefRebuilt) |
| return FORMAT_ERROR; |
| |
| ReleaseEncryptHandler(); |
| if (!RebuildCrossRef()) |
| return FORMAT_ERROR; |
| |
| eRet = SetEncryptHandler(); |
| if (eRet != SUCCESS) |
| return eRet; |
| |
| m_pDocument->LoadDoc(); |
| if (!m_pDocument->GetRoot()) |
| return FORMAT_ERROR; |
| } |
| if (GetRootObjNum() == 0) { |
| ReleaseEncryptHandler(); |
| if (!RebuildCrossRef() || GetRootObjNum() == 0) |
| return FORMAT_ERROR; |
| |
| eRet = SetEncryptHandler(); |
| if (eRet != SUCCESS) |
| return eRet; |
| } |
| if (m_pSecurityHandler && !m_pSecurityHandler->IsMetadataEncrypted()) { |
| CPDF_Reference* pMetadata = |
| ToReference(m_pDocument->GetRoot()->GetObjectFor("Metadata")); |
| if (pMetadata) |
| m_pSyntax->m_MetadataObjnum = pMetadata->GetRefObjNum(); |
| } |
| return SUCCESS; |
| } |
| |
| CPDF_Parser::Error CPDF_Parser::SetEncryptHandler() { |
| ReleaseEncryptHandler(); |
| if (!GetTrailer()) |
| return FORMAT_ERROR; |
| |
| CPDF_Object* pEncryptObj = GetTrailer()->GetObjectFor("Encrypt"); |
| if (pEncryptObj) { |
| if (CPDF_Dictionary* pEncryptDict = pEncryptObj->AsDictionary()) { |
| SetEncryptDictionary(pEncryptDict); |
| } else if (CPDF_Reference* pRef = pEncryptObj->AsReference()) { |
| pEncryptObj = m_pDocument->GetOrParseIndirectObject(pRef->GetRefObjNum()); |
| if (pEncryptObj) |
| SetEncryptDictionary(pEncryptObj->GetDict()); |
| } |
| } |
| |
| if (m_pEncryptDict) { |
| CFX_ByteString filter = m_pEncryptDict->GetStringFor("Filter"); |
| if (filter != "Standard") |
| return HANDLER_ERROR; |
| |
| std::unique_ptr<CPDF_SecurityHandler> pSecurityHandler = |
| pdfium::MakeUnique<CPDF_SecurityHandler>(); |
| if (!pSecurityHandler->OnInit(this, m_pEncryptDict.Get())) |
| return PASSWORD_ERROR; |
| |
| m_pSecurityHandler = std::move(pSecurityHandler); |
| auto pCryptoHandler = pdfium::MakeRetain<CPDF_CryptoHandler>(); |
| if (!pCryptoHandler->Init(m_pEncryptDict.Get(), m_pSecurityHandler.get())) |
| return HANDLER_ERROR; |
| m_pSyntax->SetEncrypt(pCryptoHandler); |
| } |
| return SUCCESS; |
| } |
| |
| void CPDF_Parser::ReleaseEncryptHandler() { |
| m_pSyntax->m_pCryptoHandler.Reset(); |
| m_pSecurityHandler.reset(); |
| SetEncryptDictionary(nullptr); |
| } |
| |
| FX_FILESIZE CPDF_Parser::GetObjectOffset(uint32_t objnum) const { |
| if (!IsValidObjectNumber(objnum)) |
| return 0; |
| |
| if (GetObjectType(objnum) == ObjectType::kNotCompressed) |
| return GetObjectPositionOrZero(objnum); |
| |
| if (GetObjectType(objnum) == ObjectType::kCompressed) { |
| FX_FILESIZE pos = GetObjectPositionOrZero(objnum); |
| return GetObjectPositionOrZero(pos); |
| } |
| return 0; |
| } |
| |
| // Ideally, all the cross reference entries should be verified. |
| // In reality, we rarely see well-formed cross references don't match |
| // with the objects. crbug/602650 showed a case where object numbers |
| // in the cross reference table are all off by one. |
| bool CPDF_Parser::VerifyCrossRefV4() { |
| for (const auto& it : m_ObjectInfo) { |
| if (it.second.pos == 0) |
| continue; |
| // Find the first non-zero position. |
| FX_FILESIZE SavedPos = m_pSyntax->GetPos(); |
| m_pSyntax->SetPos(it.second.pos); |
| bool is_num = false; |
| CFX_ByteString num_str = m_pSyntax->GetNextWord(&is_num); |
| m_pSyntax->SetPos(SavedPos); |
| if (!is_num || num_str.IsEmpty() || |
| FXSYS_atoui(num_str.c_str()) != it.first) { |
| // If the object number read doesn't match the one stored, |
| // something is wrong with the cross reference table. |
| return false; |
| } else { |
| return true; |
| } |
| } |
| return true; |
| } |
| |
| bool CPDF_Parser::LoadAllCrossRefV4(FX_FILESIZE xrefpos) { |
| if (!LoadCrossRefV4(xrefpos, 0, true)) |
| return false; |
| |
| std::unique_ptr<CPDF_Dictionary> trailer = LoadTrailerV4(); |
| if (!trailer) |
| return false; |
| |
| m_Trailers.push_back(std::move(trailer)); |
| m_TrailerPos = m_Trailers.size() - 1; |
| int32_t xrefsize = GetDirectInteger(GetTrailer(), "Size"); |
| if (xrefsize > 0 && xrefsize <= kMaxXRefSize) |
| ShrinkObjectMap(xrefsize); |
| |
| std::vector<FX_FILESIZE> CrossRefList; |
| std::vector<FX_FILESIZE> XRefStreamList; |
| std::set<FX_FILESIZE> seen_xrefpos; |
| |
| CrossRefList.push_back(xrefpos); |
| XRefStreamList.push_back(GetDirectInteger(GetTrailer(), "XRefStm")); |
| seen_xrefpos.insert(xrefpos); |
| |
| // When the trailer doesn't have Prev entry or Prev entry value is not |
| // numerical, GetDirectInteger() returns 0. Loading will end. |
| xrefpos = GetDirectInteger(GetTrailer(), "Prev"); |
| while (xrefpos) { |
| // Check for circular references. |
| if (pdfium::ContainsKey(seen_xrefpos, xrefpos)) |
| return false; |
| |
| seen_xrefpos.insert(xrefpos); |
| |
| // SLOW ... |
| CrossRefList.insert(CrossRefList.begin(), xrefpos); |
| LoadCrossRefV4(xrefpos, 0, true); |
| |
| std::unique_ptr<CPDF_Dictionary> pDict(LoadTrailerV4()); |
| if (!pDict) |
| return false; |
| |
| xrefpos = GetDirectInteger(pDict.get(), "Prev"); |
| |
| // SLOW ... |
| XRefStreamList.insert(XRefStreamList.begin(), |
| pDict->GetIntegerFor("XRefStm")); |
| m_Trailers.push_back(std::move(pDict)); |
| } |
| |
| for (size_t i = 0; i < CrossRefList.size(); ++i) { |
| if (!LoadCrossRefV4(CrossRefList[i], XRefStreamList[i], false)) |
| return false; |
| if (i == 0 && !VerifyCrossRefV4()) |
| return false; |
| } |
| return true; |
| } |
| |
| bool CPDF_Parser::LoadLinearizedAllCrossRefV4(FX_FILESIZE xrefpos, |
| uint32_t dwObjCount) { |
| if (!LoadLinearizedCrossRefV4(xrefpos, dwObjCount)) |
| return false; |
| |
| std::unique_ptr<CPDF_Dictionary> trailer = LoadTrailerV4(); |
| if (!trailer) |
| return false; |
| |
| m_Trailers.push_back(std::move(trailer)); |
| m_TrailerPos = m_Trailers.size() - 1; |
| int32_t xrefsize = GetDirectInteger(GetTrailer(), "Size"); |
| if (xrefsize == 0) |
| return false; |
| |
| std::vector<FX_FILESIZE> CrossRefList; |
| std::vector<FX_FILESIZE> XRefStreamList; |
| std::set<FX_FILESIZE> seen_xrefpos; |
| |
| CrossRefList.push_back(xrefpos); |
| XRefStreamList.push_back(GetDirectInteger(GetTrailer(), "XRefStm")); |
| seen_xrefpos.insert(xrefpos); |
| |
| xrefpos = GetDirectInteger(GetTrailer(), "Prev"); |
| while (xrefpos) { |
| // Check for circular references. |
| if (pdfium::ContainsKey(seen_xrefpos, xrefpos)) |
| return false; |
| |
| seen_xrefpos.insert(xrefpos); |
| |
| // SLOW ... |
| CrossRefList.insert(CrossRefList.begin(), xrefpos); |
| LoadCrossRefV4(xrefpos, 0, true); |
| |
| std::unique_ptr<CPDF_Dictionary> pDict(LoadTrailerV4()); |
| if (!pDict) |
| return false; |
| |
| xrefpos = GetDirectInteger(pDict.get(), "Prev"); |
| |
| // SLOW ... |
| XRefStreamList.insert(XRefStreamList.begin(), |
| pDict->GetIntegerFor("XRefStm")); |
| m_Trailers.push_back(std::move(pDict)); |
| } |
| |
| for (size_t i = 1; i < CrossRefList.size(); ++i) { |
| if (!LoadCrossRefV4(CrossRefList[i], XRefStreamList[i], false)) |
| return false; |
| } |
| return true; |
| } |
| |
| bool CPDF_Parser::LoadLinearizedCrossRefV4(FX_FILESIZE pos, |
| uint32_t dwObjCount) { |
| FX_FILESIZE dwStartPos = pos - m_pSyntax->m_HeaderOffset; |
| |
| m_pSyntax->SetPos(dwStartPos); |
| m_SortedOffset.insert(pos); |
| std::vector<CrossRefObjData> objects; |
| if (!ParseAndAppendCrossRefSubsectionData(0, dwObjCount, &objects)) |
| return false; |
| MergeCrossRefObjectsData(objects); |
| return true; |
| } |
| |
| bool CPDF_Parser::ParseAndAppendCrossRefSubsectionData( |
| uint32_t start_objnum, |
| uint32_t count, |
| std::vector<CrossRefObjData>* out_objects) { |
| // Each entry shall be exactly 20 byte. |
| // A sample entry looks like: |
| // "0000000000 00007 f\r\n" |
| static constexpr int32_t kEntryConstSize = 20; |
| |
| if (!out_objects) { |
| m_pSyntax->SetPos(m_pSyntax->GetPos() + count * kEntryConstSize); |
| return true; |
| } |
| const size_t start_obj_index = out_objects->size(); |
| out_objects->resize(start_obj_index + count); |
| |
| std::vector<char> buf(1024 * kEntryConstSize + 1); |
| buf[1024 * kEntryConstSize] = '\0'; |
| |
| int32_t nBlocks = count / 1024 + 1; |
| for (int32_t block = 0; block < nBlocks; block++) { |
| int32_t block_size = block == nBlocks - 1 ? count % 1024 : 1024; |
| if (!m_pSyntax->ReadBlock(reinterpret_cast<uint8_t*>(buf.data()), |
| block_size * kEntryConstSize)) |
| return false; |
| |
| for (int32_t i = 0; i < block_size; i++) { |
| CrossRefObjData& obj_data = |
| (*out_objects)[start_obj_index + block * 1024 + i]; |
| |
| const uint32_t objnum = start_objnum + block * 1024 + i; |
| |
| obj_data.obj_num = objnum; |
| |
| ObjectInfo& info = obj_data.info; |
| |
| char* pEntry = &buf[i * kEntryConstSize]; |
| if (pEntry[17] == 'f') { |
| info.pos = 0; |
| info.type = ObjectType::kFree; |
| } else { |
| const FX_SAFE_FILESIZE offset = FXSYS_atoi64(pEntry); |
| if (!offset.IsValid()) |
| return false; |
| |
| if (offset.ValueOrDie() == 0) { |
| for (int32_t c = 0; c < 10; c++) { |
| if (!std::isdigit(pEntry[c])) |
| return false; |
| } |
| } |
| |
| info.pos = offset.ValueOrDie(); |
| |
| // TODO(art-snake): The info.gennum is uint16_t, but version may be |
| // greated than max<uint16_t>. Needs solve this issue. |
| const int32_t version = FXSYS_atoi(pEntry + 11); |
| info.gennum = version; |
| info.type = ObjectType::kNotCompressed; |
| } |
| } |
| } |
| return true; |
| } |
| |
| bool CPDF_Parser::ParseCrossRefV4(std::vector<CrossRefObjData>* out_objects, |
| uint32_t* start_obj_num_at_last_block) { |
| if (out_objects) |
| out_objects->clear(); |
| |
| if (m_pSyntax->GetKeyword() != "xref") |
| return false; |
| std::vector<CrossRefObjData> result_objects; |
| while (1) { |
| FX_FILESIZE SavedPos = m_pSyntax->GetPos(); |
| bool bIsNumber; |
| CFX_ByteString word = m_pSyntax->GetNextWord(&bIsNumber); |
| if (word.IsEmpty()) { |
| return false; |
| } |
| |
| if (!bIsNumber) { |
| m_pSyntax->SetPos(SavedPos); |
| break; |
| } |
| |
| uint32_t start_objnum = FXSYS_atoui(word.c_str()); |
| if (start_objnum >= kMaxObjectNumber) |
| return false; |
| if (start_obj_num_at_last_block) |
| *start_obj_num_at_last_block = start_objnum; |
| |
| uint32_t count = m_pSyntax->GetDirectNum(); |
| m_pSyntax->ToNextWord(); |
| SavedPos = m_pSyntax->GetPos(); |
| |
| if (!ParseAndAppendCrossRefSubsectionData( |
| start_objnum, count, out_objects ? &result_objects : nullptr)) { |
| return false; |
| } |
| } |
| if (out_objects) |
| *out_objects = std::move(result_objects); |
| return true; |
| } |
| |
| bool CPDF_Parser::LoadCrossRefV4(FX_FILESIZE pos, |
| FX_FILESIZE streampos, |
| bool bSkip) { |
| m_pSyntax->SetPos(pos); |
| if (m_pSyntax->GetKeyword() != "xref") |
| return false; |
| |
| m_SortedOffset.insert(pos); |
| if (streampos) |
| m_SortedOffset.insert(streampos); |
| |
| m_pSyntax->SetPos(pos); |
| std::vector<CrossRefObjData> objects; |
| if (!ParseCrossRefV4(bSkip ? nullptr : &objects, &m_dwXrefStartObjNum)) |
| return false; |
| |
| MergeCrossRefObjectsData(objects); |
| |
| return !streampos || LoadCrossRefV5(&streampos, false); |
| } |
| |
| void CPDF_Parser::MergeCrossRefObjectsData( |
| const std::vector<CrossRefObjData>& objects) { |
| for (const auto& obj : objects) { |
| m_ObjectInfo[obj.obj_num] = obj.info; |
| if (obj.info.type != ObjectType::kFree) { |
| if (obj.info.gennum > 0) |
| m_bVersionUpdated = true; |
| if (obj.info.type == ObjectType::kNotCompressed && |
| obj.info.pos < m_pSyntax->m_FileLen) { |
| m_SortedOffset.insert(obj.info.pos); |
| } |
| } |
| } |
| } |
| |
| bool CPDF_Parser::LoadAllCrossRefV5(FX_FILESIZE xrefpos) { |
| if (!LoadCrossRefV5(&xrefpos, true)) |
| return false; |
| |
| std::set<FX_FILESIZE> seen_xrefpos; |
| while (xrefpos) { |
| seen_xrefpos.insert(xrefpos); |
| if (!LoadCrossRefV5(&xrefpos, false)) |
| return false; |
| |
| // Check for circular references. |
| if (pdfium::ContainsKey(seen_xrefpos, xrefpos)) |
| return false; |
| } |
| m_ObjectStreamMap.clear(); |
| m_bXRefStream = true; |
| return true; |
| } |
| |
| bool CPDF_Parser::RebuildCrossRef() { |
| m_ObjectInfo.clear(); |
| m_SortedOffset.clear(); |
| m_Trailers.clear(); |
| m_TrailerPos = CPDF_Parser::kInvalidPos; |
| |
| ParserState state = ParserState::kDefault; |
| int32_t inside_index = 0; |
| uint32_t objnum = 0; |
| uint32_t gennum = 0; |
| int32_t depth = 0; |
| const uint32_t kBufferSize = 4096; |
| std::vector<uint8_t> buffer(kBufferSize); |
| |
| FX_FILESIZE pos = m_pSyntax->m_HeaderOffset; |
| FX_FILESIZE start_pos = 0; |
| FX_FILESIZE start_pos1 = 0; |
| FX_FILESIZE last_obj = -1; |
| FX_FILESIZE last_xref = -1; |
| FX_FILESIZE last_trailer = -1; |
| |
| while (pos < m_pSyntax->m_FileLen) { |
| const FX_FILESIZE saved_pos = pos; |
| bool bOverFlow = false; |
| uint32_t size = |
| std::min((uint32_t)(m_pSyntax->m_FileLen - pos), kBufferSize); |
| if (!m_pSyntax->GetFileAccess()->ReadBlock(buffer.data(), pos, size)) |
| break; |
| |
| for (uint32_t i = 0; i < size; i++) { |
| uint8_t byte = buffer[i]; |
| switch (state) { |
| case ParserState::kDefault: |
| if (PDFCharIsWhitespace(byte)) { |
| state = ParserState::kWhitespace; |
| } else if (std::isdigit(byte)) { |
| --i; |
| state = ParserState::kWhitespace; |
| } else if (byte == '%') { |
| inside_index = 0; |
| state = ParserState::kComment; |
| } else if (byte == '(') { |
| state = ParserState::kString; |
| depth = 1; |
| } else if (byte == '<') { |
| inside_index = 1; |
| state = ParserState::kHexString; |
| } else if (byte == '\\') { |
| state = ParserState::kEscapedString; |
| } else if (byte == 't') { |
| state = ParserState::kTrailer; |
| inside_index = 1; |
| } |
| break; |
| |
| case ParserState::kWhitespace: |
| if (std::isdigit(byte)) { |
| start_pos = pos + i; |
| state = ParserState::kObjNum; |
| objnum = FXSYS_DecimalCharToInt(static_cast<wchar_t>(byte)); |
| } else if (byte == 't') { |
| state = ParserState::kTrailer; |
| inside_index = 1; |
| } else if (byte == 'x') { |
| state = ParserState::kXref; |
| inside_index = 1; |
| } else if (!PDFCharIsWhitespace(byte)) { |
| --i; |
| state = ParserState::kDefault; |
| } |
| break; |
| |
| case ParserState::kObjNum: |
| if (std::isdigit(byte)) { |
| objnum = objnum * 10 + |
| FXSYS_DecimalCharToInt(static_cast<wchar_t>(byte)); |
| } else if (PDFCharIsWhitespace(byte)) { |
| state = ParserState::kPostObjNum; |
| } else { |
| --i; |
| state = ParserState::kEndObj; |
| inside_index = 0; |
| } |
| break; |
| |
| case ParserState::kPostObjNum: |
| if (std::isdigit(byte)) { |
| start_pos1 = pos + i; |
| state = ParserState::kGenNum; |
| gennum = FXSYS_DecimalCharToInt(static_cast<wchar_t>(byte)); |
| } else if (byte == 't') { |
| state = ParserState::kTrailer; |
| inside_index = 1; |
| } else if (!PDFCharIsWhitespace(byte)) { |
| --i; |
| state = ParserState::kDefault; |
| } |
| break; |
| |
| case ParserState::kGenNum: |
| if (std::isdigit(byte)) { |
| gennum = gennum * 10 + |
| FXSYS_DecimalCharToInt(static_cast<wchar_t>(byte)); |
| } else if (PDFCharIsWhitespace(byte)) { |
| state = ParserState::kPostGenNum; |
| } else { |
| --i; |
| state = ParserState::kDefault; |
| } |
| break; |
| |
| case ParserState::kPostGenNum: |
| if (byte == 'o') { |
| state = ParserState::kBeginObj; |
| inside_index = 1; |
| } else if (std::isdigit(byte)) { |
| objnum = gennum; |
| gennum = FXSYS_DecimalCharToInt(static_cast<wchar_t>(byte)); |
| start_pos = start_pos1; |
| start_pos1 = pos + i; |
| state = ParserState::kGenNum; |
| } else if (byte == 't') { |
| state = ParserState::kTrailer; |
| inside_index = 1; |
| } else if (!PDFCharIsWhitespace(byte)) { |
| --i; |
| state = ParserState::kDefault; |
| } |
| break; |
| |
| case ParserState::kBeginObj: |
| switch (inside_index) { |
| case 1: |
| if (byte != 'b') { |
| --i; |
| state = ParserState::kDefault; |
| } else { |
| inside_index++; |
| } |
| break; |
| case 2: |
| if (byte != 'j') { |
| --i; |
| state = ParserState::kDefault; |
| } else { |
| inside_index++; |
| } |
| break; |
| case 3: |
| if (PDFCharIsWhitespace(byte) || PDFCharIsDelimiter(byte)) { |
| FX_FILESIZE obj_pos = start_pos - m_pSyntax->m_HeaderOffset; |
| m_SortedOffset.insert(obj_pos); |
| last_obj = start_pos; |
| FX_FILESIZE obj_end = 0; |
| std::unique_ptr<CPDF_Object> pObject = |
| ParseIndirectObjectAtByStrict(m_pDocument.Get(), obj_pos, |
| objnum, &obj_end); |
| if (CPDF_Stream* pStream = ToStream(pObject.get())) { |
| if (CPDF_Dictionary* pDict = pStream->GetDict()) { |
| if ((pDict->KeyExist("Type")) && |
| (pDict->GetStringFor("Type") == "XRef" && |
| pDict->KeyExist("Size"))) { |
| CPDF_Object* pRoot = pDict->GetObjectFor("Root"); |
| if (pRoot && pRoot->GetDict() && |
| pRoot->GetDict()->GetObjectFor("Pages")) { |
| m_Trailers.push_back(ToDictionary(pDict->Clone())); |
| m_TrailerPos = m_Trailers.size() - 1; |
| } |
| } |
| } |
| } |
| |
| FX_FILESIZE offset = 0; |
| m_pSyntax->SetPos(obj_pos); |
| offset = m_pSyntax->FindTag("obj", 0); |
| if (offset == -1) |
| offset = 0; |
| else |
| offset += 3; |
| |
| FX_FILESIZE nLen = obj_end - obj_pos - offset; |
| if ((uint32_t)nLen > size - i) { |
| pos = obj_end + m_pSyntax->m_HeaderOffset; |
| bOverFlow = true; |
| } else { |
| i += (uint32_t)nLen; |
| } |
| |
| if (!m_ObjectInfo.empty() && IsValidObjectNumber(objnum) && |
| m_ObjectInfo[objnum].pos) { |
| if (pObject) { |
| uint32_t oldgen = GetObjectGenNum(objnum); |
| m_ObjectInfo[objnum].pos = obj_pos; |
| m_ObjectInfo[objnum].gennum = gennum; |
| if (oldgen != gennum) |
| m_bVersionUpdated = true; |
| } |
| } else { |
| m_ObjectInfo[objnum].pos = obj_pos; |
| m_ObjectInfo[objnum].type = ObjectType::kNotCompressed; |
| m_ObjectInfo[objnum].gennum = gennum; |
| } |
| } |
| --i; |
| state = ParserState::kDefault; |
| break; |
| } |
| break; |
| |
| case ParserState::kTrailer: |
| if (inside_index == 7) { |
| if (PDFCharIsWhitespace(byte) || PDFCharIsDelimiter(byte)) { |
| last_trailer = pos + i - 7; |
| m_pSyntax->SetPos(pos + i - m_pSyntax->m_HeaderOffset); |
| |
| std::unique_ptr<CPDF_Object> pObj = |
| m_pSyntax->GetObject(m_pDocument.Get(), 0, 0, true); |
| if (pObj) { |
| if (pObj->IsDictionary() || pObj->AsStream()) { |
| CPDF_Stream* pStream = pObj->AsStream(); |
| if (CPDF_Dictionary* pTrailer = |
| pStream ? pStream->GetDict() : pObj->AsDictionary()) { |
| if (GetTrailer()) { |
| CPDF_Object* pRoot = pTrailer->GetObjectFor("Root"); |
| CPDF_Reference* pRef = ToReference(pRoot); |
| if (!pRoot || |
| (pRef && IsValidObjectNumber(pRef->GetRefObjNum()) && |
| m_ObjectInfo[pRef->GetRefObjNum()].pos != 0)) { |
| auto it = pTrailer->begin(); |
| while (it != pTrailer->end()) { |
| const CFX_ByteString& key = it->first; |
| CPDF_Object* pElement = it->second.get(); |
| ++it; |
| uint32_t dwObjNum = |
| pElement ? pElement->GetObjNum() : 0; |
| if (dwObjNum) { |
| GetTrailer()->SetNewFor<CPDF_Reference>( |
| key, m_pDocument.Get(), dwObjNum); |
| } else { |
| GetTrailer()->SetFor(key, pElement->Clone()); |
| } |
| } |
| } |
| } else { |
| if (pObj->IsStream()) |
| m_Trailers.push_back(ToDictionary(pTrailer->Clone())); |
| else |
| m_Trailers.push_back(ToDictionary(std::move(pObj))); |
| m_TrailerPos = m_Trailers.size() - 1; |
| |
| FX_FILESIZE dwSavePos = m_pSyntax->GetPos(); |
| CFX_ByteString strWord = m_pSyntax->GetKeyword(); |
| if (!strWord.Compare("startxref")) { |
| bool bNumber; |
| CFX_ByteString bsOffset = |
| m_pSyntax->GetNextWord(&bNumber); |
| if (bNumber) |
| m_LastXRefOffset = FXSYS_atoi(bsOffset.c_str()); |
| } |
| m_pSyntax->SetPos(dwSavePos); |
| } |
| } |
| } |
| } |
| } |
| --i; |
| state = ParserState::kDefault; |
| } else if (byte == "trailer"[inside_index]) { |
| inside_index++; |
| } else { |
| --i; |
| state = ParserState::kDefault; |
| } |
| break; |
| |
| case ParserState::kXref: |
| if (inside_index == 4) { |
| last_xref = pos + i - 4; |
| state = ParserState::kWhitespace; |
| } else if (byte == "xref"[inside_index]) { |
| inside_index++; |
| } else { |
| --i; |
| state = ParserState::kDefault; |
| } |
| break; |
| |
| case ParserState::kComment: |
| if (PDFCharIsLineEnding(byte)) |
| state = ParserState::kDefault; |
| break; |
| |
| case ParserState::kString: |
| if (byte == ')') { |
| if (depth > 0) |
| depth--; |
| } else if (byte == '(') { |
| depth++; |
| } |
| |
| if (!depth) |
| state = ParserState::kDefault; |
| break; |
| |
| case ParserState::kHexString: |
| if (byte == '>' || (byte == '<' && inside_index == 1)) |
| state = ParserState::kDefault; |
| inside_index = 0; |
| break; |
| |
| case ParserState::kEscapedString: |
| if (PDFCharIsDelimiter(byte) || PDFCharIsWhitespace(byte)) { |
| --i; |
| state = ParserState::kDefault; |
| } |
| break; |
| |
| case ParserState::kEndObj: |
| if (PDFCharIsWhitespace(byte)) { |
| state = ParserState::kDefault; |
| } else if (byte == '%' || byte == '(' || byte == '<' || |
| byte == '\\') { |
| state = ParserState::kDefault; |
| --i; |
| } else if (inside_index == 6) { |
| state = ParserState::kDefault; |
| --i; |
| } else if (byte == "endobj"[inside_index]) { |
| inside_index++; |
| } |
| break; |
| } |
| |
| if (bOverFlow) { |
| size = 0; |
| break; |
| } |
| } |
| pos += size; |
| |
| // If the position has not changed at all or went backwards in a loop |
| // iteration, then break out to prevent infinite looping. |
| if (pos <= saved_pos) |
| break; |
| } |
| |
| if (last_xref != -1 && last_xref > last_obj) |
| last_trailer = last_xref; |
| else if (last_trailer == -1 || last_xref < last_obj) |
| last_trailer = m_pSyntax->m_FileLen; |
| |
| m_SortedOffset.insert(last_trailer - m_pSyntax->m_HeaderOffset); |
| return GetTrailer() && !m_ObjectInfo.empty(); |
| } |
| |
| bool CPDF_Parser::LoadCrossRefV5(FX_FILESIZE* pos, bool bMainXRef) { |
| std::unique_ptr<CPDF_Object> pObject( |
| ParseIndirectObjectAt(m_pDocument.Get(), *pos, 0)); |
| if (!pObject) |
| return false; |
| |
| uint32_t objnum = pObject->m_ObjNum; |
| if (!objnum) |
| return false; |
| |
| CPDF_Object* pUnownedObject = pObject.get(); |
| if (m_pDocument) { |
| CPDF_Dictionary* pRootDict = m_pDocument->GetRoot(); |
| if (pRootDict && pRootDict->GetObjNum() == objnum) |
| return false; |
| if (!m_pDocument->ReplaceIndirectObjectIfHigherGeneration( |
| objnum, std::move(pObject))) { |
| return false; |
| } |
| } |
| |
| CPDF_Stream* pStream = pUnownedObject->AsStream(); |
| if (!pStream) |
| return false; |
| |
| CPDF_Dictionary* pDict = pStream->GetDict(); |
| *pos = pDict->GetIntegerFor("Prev"); |
| int32_t size = pDict->GetIntegerFor("Size"); |
| if (size < 0) |
| return false; |
| |
| std::unique_ptr<CPDF_Dictionary> pNewTrailer = ToDictionary(pDict->Clone()); |
| if (bMainXRef) { |
| m_Trailers.push_back(std::move(pNewTrailer)); |
| m_TrailerPos = m_Trailers.size() - 1; |
| ShrinkObjectMap(size); |
| for (auto& it : m_ObjectInfo) |
| it.second.type = ObjectType::kFree; |
| } else { |
| m_Trailers.push_back(std::move(pNewTrailer)); |
| } |
| |
| std::vector<std::pair<int32_t, int32_t>> arrIndex; |
| CPDF_Array* pArray = pDict->GetArrayFor("Index"); |
| if (pArray) { |
| for (size_t i = 0; i < pArray->GetCount() / 2; i++) { |
| CPDF_Object* pStartNumObj = pArray->GetObjectAt(i * 2); |
| CPDF_Object* pCountObj = pArray->GetObjectAt(i * 2 + 1); |
| |
| if (ToNumber(pStartNumObj) && ToNumber(pCountObj)) { |
| int nStartNum = pStartNumObj->GetInteger(); |
| int nCount = pCountObj->GetInteger(); |
| if (nStartNum >= 0 && nCount > 0) |
| arrIndex.push_back(std::make_pair(nStartNum, nCount)); |
| } |
| } |
| } |
| |
| if (arrIndex.size() == 0) |
| arrIndex.push_back(std::make_pair(0, size)); |
| |
| pArray = pDict->GetArrayFor("W"); |
| if (!pArray) |
| return false; |
| |
| std::vector<uint32_t> WidthArray; |
| FX_SAFE_UINT32 dwAccWidth = 0; |
| for (size_t i = 0; i < pArray->GetCount(); ++i) { |
| WidthArray.push_back(pArray->GetIntegerAt(i)); |
| dwAccWidth += WidthArray[i]; |
| } |
| |
| if (!dwAccWidth.IsValid() || WidthArray.size() < 3) |
| return false; |
| |
| uint32_t totalWidth = dwAccWidth.ValueOrDie(); |
| auto pAcc = pdfium::MakeRetain<CPDF_StreamAcc>(pStream); |
| pAcc->LoadAllData(); |
| |
| const uint8_t* pData = pAcc->GetData(); |
| uint32_t dwTotalSize = pAcc->GetSize(); |
| uint32_t segindex = 0; |
| for (uint32_t i = 0; i < arrIndex.size(); i++) { |
| int32_t startnum = arrIndex[i].first; |
| if (startnum < 0) |
| continue; |
| |
| m_dwXrefStartObjNum = pdfium::base::checked_cast<uint32_t>(startnum); |
| uint32_t count = pdfium::base::checked_cast<uint32_t>(arrIndex[i].second); |
| FX_SAFE_UINT32 dwCaculatedSize = segindex; |
| dwCaculatedSize += count; |
| dwCaculatedSize *= totalWidth; |
| if (!dwCaculatedSize.IsValid() || |
| dwCaculatedSize.ValueOrDie() > dwTotalSize) { |
| continue; |
| } |
| |
| const uint8_t* segstart = pData + segindex * totalWidth; |
| FX_SAFE_UINT32 dwMaxObjNum = startnum; |
| dwMaxObjNum += count; |
| uint32_t dwV5Size = m_ObjectInfo.empty() ? 0 : GetLastObjNum() + 1; |
| if (!dwMaxObjNum.IsValid() || dwMaxObjNum.ValueOrDie() > dwV5Size) |
| continue; |
| |
| for (uint32_t j = 0; j < count; j++) { |
| ObjectType type = ObjectType::kNotCompressed; |
| const uint8_t* entrystart = segstart + j * totalWidth; |
| if (WidthArray[0]) { |
| const int cross_ref_stream_obj_type = |
| GetVarInt(entrystart, WidthArray[0]); |
| type = GetObjectTypeFromCrossRefStreamType(cross_ref_stream_obj_type); |
| } |
| |
| if (GetObjectType(startnum + j) == ObjectType::kNull) { |
| FX_FILESIZE offset = |
| GetVarInt(entrystart + WidthArray[0], WidthArray[1]); |
| m_ObjectInfo[startnum + j].pos = offset; |
| m_SortedOffset.insert(offset); |
| continue; |
| } |
| |
| if (GetObjectType(startnum + j) != ObjectType::kFree) |
| continue; |
| |
| ObjectInfo& info = m_ObjectInfo[startnum + j]; |
| |
| info.type = type; |
| if (type == ObjectType::kFree) { |
| info.pos = 0; |
| } else { |
| const FX_FILESIZE entry_value = |
| GetVarInt(entrystart + WidthArray[0], WidthArray[1]); |
| if (type == ObjectType::kNotCompressed) { |
| const auto object_offset = entry_value; |
| m_SortedOffset.insert(object_offset); |
| info.pos = object_offset; |
| } else { |
| const auto archive_obj_num = entry_value; |
| info.archive_obj_num = archive_obj_num; |
| if (archive_obj_num < 0 || !IsValidObjectNumber(archive_obj_num)) |
| return false; |
| m_ObjectInfo[archive_obj_num].type = ObjectType::kNull; |
| } |
| } |
| } |
| segindex += count; |
| } |
| return true; |
| } |
| |
| CPDF_Array* CPDF_Parser::GetIDArray() { |
| if (!GetTrailer()) |
| return nullptr; |
| |
| CPDF_Object* pID = GetTrailer()->GetObjectFor("ID"); |
| if (!pID) |
| return nullptr; |
| |
| CPDF_Reference* pRef = pID->AsReference(); |
| if (!pRef) |
| return ToArray(pID); |
| |
| std::unique_ptr<CPDF_Object> pNewObj = |
| ParseIndirectObject(nullptr, pRef->GetRefObjNum()); |
| pID = pNewObj.get(); |
| GetTrailer()->SetFor("ID", std::move(pNewObj)); |
| return ToArray(pID); |
| } |
| |
| uint32_t CPDF_Parser::GetRootObjNum() { |
| CPDF_Reference* pRef = |
| ToReference(GetTrailer() ? GetTrailer()->GetObjectFor("Root") : nullptr); |
| return pRef ? pRef->GetRefObjNum() : 0; |
| } |
| |
| uint32_t CPDF_Parser::GetInfoObjNum() { |
| CPDF_Reference* pRef = |
| ToReference(GetTrailer() ? GetTrailer()->GetObjectFor("Info") : nullptr); |
| if (pRef) |
| return pRef->GetRefObjNum(); |
| |
| // Search trailers array from latest to earliest revision, as we want the |
| // most recent Info object number. |
| // See PDF 1.7 spec, section 3.4.5 - Incremental Updates. |
| for (auto it = m_Trailers.rbegin(); it != m_Trailers.rend(); ++it) { |
| pRef = ToReference(it->get()->GetObjectFor("Info")); |
| if (pRef) |
| return pRef->GetRefObjNum(); |
| } |
| return 0; |
| } |
| |
| std::unique_ptr<CPDF_Object> CPDF_Parser::ParseIndirectObject( |
| CPDF_IndirectObjectHolder* pObjList, |
| uint32_t objnum) { |
| if (!IsValidObjectNumber(objnum)) |
| return nullptr; |
| |
| // Prevent circular parsing the same object. |
| if (pdfium::ContainsKey(m_ParsingObjNums, objnum)) |
| return nullptr; |
| |
| pdfium::ScopedSetInsertion<uint32_t> local_insert(&m_ParsingObjNums, objnum); |
| if (GetObjectType(objnum) == ObjectType::kNotCompressed || |
| GetObjectType(objnum) == ObjectType::kNull) { |
| FX_FILESIZE pos = m_ObjectInfo[objnum].pos; |
| if (pos <= 0) |
| return nullptr; |
| return ParseIndirectObjectAt(pObjList, pos, objnum); |
| } |
| if (GetObjectType(objnum) != ObjectType::kCompressed) |
| return nullptr; |
| |
| CFX_RetainPtr<CPDF_StreamAcc> pObjStream = |
| GetObjectStream(m_ObjectInfo[objnum].pos); |
| if (!pObjStream) |
| return nullptr; |
| |
| auto file = pdfium::MakeRetain<CFX_MemoryStream>( |
| const_cast<uint8_t*>(pObjStream->GetData()), |
| static_cast<size_t>(pObjStream->GetSize()), false); |
| CPDF_SyntaxParser syntax; |
| syntax.InitParser(file, 0); |
| const int32_t offset = GetStreamFirst(pObjStream); |
| |
| // Read object numbers from |pObjStream| into a cache. |
| if (!pdfium::ContainsKey(m_ObjCache, pObjStream)) { |
| for (int32_t i = GetStreamNCount(pObjStream); i > 0; --i) { |
| uint32_t thisnum = syntax.GetDirectNum(); |
| uint32_t thisoff = syntax.GetDirectNum(); |
| m_ObjCache[pObjStream][thisnum] = thisoff; |
| } |
| } |
| |
| const auto it = m_ObjCache[pObjStream].find(objnum); |
| if (it == m_ObjCache[pObjStream].end()) |
| return nullptr; |
| |
| syntax.SetPos(offset + it->second); |
| return syntax.GetObject(pObjList, 0, 0, true); |
| } |
| |
| CFX_RetainPtr<CPDF_StreamAcc> CPDF_Parser::GetObjectStream(uint32_t objnum) { |
| auto it = m_ObjectStreamMap.find(objnum); |
| if (it != m_ObjectStreamMap.end()) |
| return it->second; |
| |
| if (!m_pDocument) |
| return nullptr; |
| |
| const CPDF_Stream* pStream = |
| ToStream(m_pDocument->GetOrParseIndirectObject(objnum)); |
| if (!pStream) |
| return nullptr; |
| |
| auto pStreamAcc = pdfium::MakeRetain<CPDF_StreamAcc>(pStream); |
| pStreamAcc->LoadAllData(); |
| m_ObjectStreamMap[objnum] = pStreamAcc; |
| return pStreamAcc; |
| } |
| |
| FX_FILESIZE CPDF_Parser::GetObjectSize(uint32_t objnum) const { |
| if (!IsValidObjectNumber(objnum)) |
| return 0; |
| |
| if (GetObjectType(objnum) == ObjectType::kCompressed) |
| objnum = GetObjectPositionOrZero(objnum); |
| |
| if (GetObjectType(objnum) != ObjectType::kNotCompressed && |
| GetObjectType(objnum) != ObjectType::kNull) |
| return 0; |
| |
| FX_FILESIZE offset = GetObjectPositionOrZero(objnum); |
| if (offset == 0) |
| return 0; |
| |
| auto it = m_SortedOffset.find(offset); |
| if (it == m_SortedOffset.end() || ++it == m_SortedOffset.end()) |
| return 0; |
| |
| return *it - offset; |
| } |
| |
| std::unique_ptr<CPDF_Object> CPDF_Parser::ParseIndirectObjectAt( |
| CPDF_IndirectObjectHolder* pObjList, |
| FX_FILESIZE pos, |
| uint32_t objnum) { |
| return ParseIndirectObjectAtInternal(pObjList, pos, objnum, false, nullptr); |
| } |
| |
| std::unique_ptr<CPDF_Object> CPDF_Parser::ParseIndirectObjectAtInternal( |
| CPDF_IndirectObjectHolder* pObjList, |
| FX_FILESIZE pos, |
| uint32_t objnum, |
| bool strict_parse, |
| FX_FILESIZE* pResultPos) { |
| FX_FILESIZE SavedPos = m_pSyntax->GetPos(); |
| m_pSyntax->SetPos(pos); |
| bool bIsNumber; |
| CFX_ByteString word = m_pSyntax->GetNextWord(&bIsNumber); |
| if (!bIsNumber) { |
| m_pSyntax->SetPos(SavedPos); |
| return nullptr; |
| } |
| |
| uint32_t parser_objnum = FXSYS_atoui(word.c_str()); |
| if (objnum && parser_objnum != objnum) { |
| m_pSyntax->SetPos(SavedPos); |
| return nullptr; |
| } |
| |
| word = m_pSyntax->GetNextWord(&bIsNumber); |
| if (!bIsNumber) { |
| m_pSyntax->SetPos(SavedPos); |
| return nullptr; |
| } |
| |
| uint32_t parser_gennum = FXSYS_atoui(word.c_str()); |
| if (m_pSyntax->GetKeyword() != "obj") { |
| m_pSyntax->SetPos(SavedPos); |
| return nullptr; |
| } |
| |
| std::unique_ptr<CPDF_Object> pObj = |
| strict_parse |
| ? m_pSyntax->GetObjectForStrict(pObjList, objnum, parser_gennum) |
| : m_pSyntax->GetObject(pObjList, objnum, parser_gennum, true); |
| |
| if (pResultPos) |
| *pResultPos = m_pSyntax->m_Pos; |
| |
| if (pObj) { |
| if (!objnum) |
| pObj->m_ObjNum = parser_objnum; |
| pObj->m_GenNum = parser_gennum; |
| } |
| |
| m_pSyntax->SetPos(SavedPos); |
| return pObj; |
| } |
| |
| std::unique_ptr<CPDF_Object> CPDF_Parser::ParseIndirectObjectAtByStrict( |
| CPDF_IndirectObjectHolder* pObjList, |
| FX_FILESIZE pos, |
| uint32_t objnum, |
| FX_FILESIZE* pResultPos) { |
| return ParseIndirectObjectAtInternal(pObjList, pos, objnum, true, pResultPos); |
| } |
| |
| uint32_t CPDF_Parser::GetFirstPageNo() const { |
| return m_pLinearized ? m_pLinearized->GetFirstPageNo() : 0; |
| } |
| |
| std::unique_ptr<CPDF_Dictionary> CPDF_Parser::LoadTrailerV4() { |
| if (m_pSyntax->GetKeyword() != "trailer") |
| return nullptr; |
| |
| return ToDictionary(m_pSyntax->GetObject(m_pDocument.Get(), 0, 0, true)); |
| } |
| |
| uint32_t CPDF_Parser::GetPermissions() const { |
| if (!m_pSecurityHandler) |
| return 0xFFFFFFFF; |
| |
| uint32_t dwPermission = m_pSecurityHandler->GetPermissions(); |
| if (m_pEncryptDict && m_pEncryptDict->GetStringFor("Filter") == "Standard") { |
| // See PDF Reference 1.7, page 123, table 3.20. |
| dwPermission &= 0xFFFFFFFC; |
| dwPermission |= 0xFFFFF0C0; |
| } |
| return dwPermission; |
| } |
| |
| bool CPDF_Parser::IsLinearizedFile( |
| const CFX_RetainPtr<IFX_SeekableReadStream>& pFileAccess, |
| uint32_t offset) { |
| m_pSyntax->InitParser(pFileAccess, offset); |
| m_pSyntax->SetPos(m_pSyntax->m_HeaderOffset + 9); |
| |
| FX_FILESIZE SavedPos = m_pSyntax->GetPos(); |
| bool bIsNumber; |
| CFX_ByteString word = m_pSyntax->GetNextWord(&bIsNumber); |
| if (!bIsNumber) |
| return false; |
| |
| uint32_t objnum = FXSYS_atoui(word.c_str()); |
| word = m_pSyntax->GetNextWord(&bIsNumber); |
| if (!bIsNumber) |
| return false; |
| |
| uint32_t gennum = FXSYS_atoui(word.c_str()); |
| if (m_pSyntax->GetKeyword() != "obj") { |
| m_pSyntax->SetPos(SavedPos); |
| return false; |
| } |
| |
| m_pLinearized = CPDF_LinearizedHeader::CreateForObject( |
| m_pSyntax->GetObject(nullptr, objnum, gennum, true)); |
| if (!m_pLinearized) |
| return false; |
| |
| m_LastXRefOffset = m_pLinearized->GetLastXRefOffset(); |
| // Move parser onto first page xref table start. |
| m_pSyntax->GetNextWord(nullptr); |
| return true; |
| } |
| |
| CPDF_Parser::Error CPDF_Parser::StartLinearizedParse( |
| const CFX_RetainPtr<IFX_SeekableReadStream>& pFileAccess, |
| CPDF_Document* pDocument) { |
| ASSERT(!m_bHasParsed); |
| m_bXRefStream = false; |
| m_LastXRefOffset = 0; |
| |
| int32_t offset = GetHeaderOffset(pFileAccess); |
| if (offset == kInvalidHeaderOffset) |
| return FORMAT_ERROR; |
| |
| if (!IsLinearizedFile(pFileAccess, offset)) |
| return StartParseInternal(pFileAccess, std::move(pDocument), offset); |
| |
| m_bHasParsed = true; |
| m_pDocument = pDocument; |
| |
| FX_FILESIZE dwFirstXRefOffset = m_pSyntax->GetPos(); |
| bool bXRefRebuilt = false; |
| bool bLoadV4 = LoadCrossRefV4(dwFirstXRefOffset, 0, false); |
| if (!bLoadV4 && !LoadCrossRefV5(&dwFirstXRefOffset, true)) { |
| if (!RebuildCrossRef()) |
| return FORMAT_ERROR; |
| |
| bXRefRebuilt = true; |
| m_LastXRefOffset = 0; |
| } |
| |
| if (bLoadV4) { |
| std::unique_ptr<CPDF_Dictionary> trailer = LoadTrailerV4(); |
| if (!trailer) |
| return SUCCESS; |
| |
| m_Trailers.push_back(std::move(trailer)); |
| m_TrailerPos = m_Trailers.size() - 1; |
| int32_t xrefsize = GetDirectInteger(GetTrailer(), "Size"); |
| if (xrefsize > 0) |
| ShrinkObjectMap(xrefsize); |
| } |
| |
| Error eRet = SetEncryptHandler(); |
| if (eRet != SUCCESS) |
| return eRet; |
| |
| m_pDocument->LoadLinearizedDoc(m_pLinearized.get()); |
| if (!m_pDocument->GetRoot() || m_pDocument->GetPageCount() == 0) { |
| if (bXRefRebuilt) |
| return FORMAT_ERROR; |
| |
| ReleaseEncryptHandler(); |
| if (!RebuildCrossRef()) |
| return FORMAT_ERROR; |
| |
| eRet = SetEncryptHandler(); |
| if (eRet != SUCCESS) |
| return eRet; |
| |
| m_pDocument->LoadLinearizedDoc(m_pLinearized.get()); |
| if (!m_pDocument->GetRoot()) |
| return FORMAT_ERROR; |
| } |
| |
| if (GetRootObjNum() == 0) { |
| ReleaseEncryptHandler(); |
| if (!RebuildCrossRef() || GetRootObjNum() == 0) |
| return FORMAT_ERROR; |
| |
| eRet = SetEncryptHandler(); |
| if (eRet != SUCCESS) |
| return eRet; |
| } |
| |
| if (m_pSecurityHandler && m_pSecurityHandler->IsMetadataEncrypted()) { |
| if (CPDF_Reference* pMetadata = |
| ToReference(m_pDocument->GetRoot()->GetObjectFor("Metadata"))) |
| m_pSyntax->m_MetadataObjnum = pMetadata->GetRefObjNum(); |
| } |
| return SUCCESS; |
| } |
| |
| bool CPDF_Parser::LoadLinearizedAllCrossRefV5(FX_FILESIZE xrefpos) { |
| if (!LoadCrossRefV5(&xrefpos, false)) |
| return false; |
| |
| std::set<FX_FILESIZE> seen_xrefpos; |
| while (xrefpos) { |
| seen_xrefpos.insert(xrefpos); |
| if (!LoadCrossRefV5(&xrefpos, false)) |
| return false; |
| |
| // Check for circular references. |
| if (pdfium::ContainsKey(seen_xrefpos, xrefpos)) |
| return false; |
| } |
| m_ObjectStreamMap.clear(); |
| m_bXRefStream = true; |
| return true; |
| } |
| |
| CPDF_Parser::Error CPDF_Parser::LoadLinearizedMainXRefTable() { |
| uint32_t dwSaveMetadataObjnum = m_pSyntax->m_MetadataObjnum; |
| m_pSyntax->m_MetadataObjnum = 0; |
| m_pSyntax->SetPos(m_LastXRefOffset - m_pSyntax->m_HeaderOffset); |
| |
| uint8_t ch = 0; |
| uint32_t dwCount = 0; |
| m_pSyntax->GetNextChar(ch); |
| while (PDFCharIsWhitespace(ch)) { |
| ++dwCount; |
| if (m_pSyntax->m_FileLen <= |
| (FX_FILESIZE)(m_pSyntax->GetPos() + m_pSyntax->m_HeaderOffset)) { |
| break; |
| } |
| m_pSyntax->GetNextChar(ch); |
| } |
| m_LastXRefOffset += dwCount; |
| m_ObjectStreamMap.clear(); |
| m_ObjCache.clear(); |
| |
| if (!LoadLinearizedAllCrossRefV4(m_LastXRefOffset, m_dwXrefStartObjNum) && |
| !LoadLinearizedAllCrossRefV5(m_LastXRefOffset)) { |
| m_LastXRefOffset = 0; |
| m_pSyntax->m_MetadataObjnum = dwSaveMetadataObjnum; |
| return FORMAT_ERROR; |
| } |
| |
| m_pSyntax->m_MetadataObjnum = dwSaveMetadataObjnum; |
| return SUCCESS; |
| } |
