diff options
| -rw-r--r-- | core/include/fpdfapi/fpdf_parser.h | 2 | ||||
| -rw-r--r-- | core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp | 161 |
2 files changed, 118 insertions, 45 deletions
diff --git a/core/include/fpdfapi/fpdf_parser.h b/core/include/fpdfapi/fpdf_parser.h index 7640c857fa..cb4e15e25d 100644 --- a/core/include/fpdfapi/fpdf_parser.h +++ b/core/include/fpdfapi/fpdf_parser.h @@ -297,6 +297,8 @@ class CPDF_SyntaxParser { CFX_ByteString ReadHexString(); + unsigned int ReadEOLMarkers(FX_FILESIZE pos); + CPDF_Stream* ReadStream(CPDF_Dictionary* pDict, PARSE_CONTEXT* pContext, FX_DWORD objnum, diff --git a/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp b/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp index e9c07e2864..f14d7d5c37 100644 --- a/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp +++ b/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp @@ -2430,65 +2430,134 @@ CPDF_Object* CPDF_SyntaxParser::GetObjectByStrict( } return NULL; } +unsigned int CPDF_SyntaxParser::ReadEOLMarkers(FX_FILESIZE pos) { + unsigned char byte1 = 0; + unsigned char byte2 = 0; + GetCharAt(pos, byte1); + GetCharAt(pos+1, byte2); + unsigned int markers = 0; + if (byte1 == '\r' && byte2 == '\n') { + markers = 2; + } else if (byte1 == '\r' || byte1 == '\n') { + markers = 1; + } + return markers; +} CPDF_Stream* CPDF_SyntaxParser::ReadStream(CPDF_Dictionary* pDict, PARSE_CONTEXT* pContext, FX_DWORD objnum, FX_DWORD gennum) { CPDF_Object* pLenObj = pDict->GetElement(FX_BSTRC("Length")); - FX_FILESIZE len = 0; + FX_FILESIZE len = -1; if (pLenObj && ((pLenObj->GetType() != PDFOBJ_REFERENCE) || - ((((CPDF_Reference*)pLenObj)->GetObjList() != NULL) && + ((((CPDF_Reference*)pLenObj)->GetObjList()) && ((CPDF_Reference*)pLenObj)->GetRefObjNum() != objnum))) { len = pLenObj->GetInteger(); } - - ToNextLine(); - FX_FILESIZE StreamStartPos = m_Pos; + //Check whether end of line markers follow the keyword 'stream'. + unsigned int numMarkers = ReadEOLMarkers(m_Pos); + m_Pos += numMarkers; + FX_FILESIZE streamStartPos = m_Pos; if (pContext) { - pContext->m_DataStart = m_Pos; - } - - CPDF_CryptoHandler* pCryptoHandler = - objnum == (FX_DWORD)m_MetadataObjnum ? NULL : m_pCryptoHandler; - if (pCryptoHandler == NULL) { - pdfium::base::CheckedNumeric<FX_FILESIZE> pos = m_Pos; - pos += len; - if (pos.IsValid() && pos.ValueOrDie() < m_FileLen) { - m_Pos = pos.ValueOrDie(); - } - GetNextWord(); - if (m_WordSize < 9 || FXSYS_memcmp(m_WordBuffer, "endstream", 9)) { - m_Pos = StreamStartPos; - FX_FILESIZE offset = FindTag(FX_BSTRC("endstream"), 0); - if (offset >= 0) { - FX_FILESIZE curPos = m_Pos; - m_Pos = StreamStartPos; - FX_FILESIZE endobjOffset = FindTag(FX_BSTRC("endobj"), 0); - if (endobjOffset < offset && endobjOffset >= 0) { - offset = endobjOffset; + pContext->m_DataStart = streamStartPos; + } + const unsigned int ENDSTREAM_LEN = sizeof("endstream") - 1; + const unsigned int ENDOBJ_LEN = sizeof("endobj") - 1; + CPDF_CryptoHandler* pCryptoHandler = objnum == (FX_DWORD)m_MetadataObjnum ? nullptr : m_pCryptoHandler; + if (!pCryptoHandler) { + FX_BOOL bSearchForKeyword = TRUE; + unsigned int prevMarkers = 0; + unsigned int nextMarkers = 0; + if (len >= 0) { + pdfium::base::CheckedNumeric<FX_FILESIZE> pos = m_Pos; + pos += len; + if (pos.IsValid() && pos.ValueOrDie() < m_FileLen) { + m_Pos = pos.ValueOrDie(); + } + prevMarkers = ReadEOLMarkers(m_Pos); + GetNextWord(); + nextMarkers = ReadEOLMarkers(m_Pos); + if (m_WordSize == ENDSTREAM_LEN && prevMarkers != 0 && nextMarkers != 0 && + FXSYS_memcmp(m_WordBuffer, "endstream", ENDSTREAM_LEN) == 0) { + bSearchForKeyword = FALSE; + } + } + if (bSearchForKeyword) { + //If len is not available, len needs to be calculated + //by searching the keywords "endstream" or "endobj". + m_Pos = streamStartPos; + FX_FILESIZE endStreamOffset = 0; + while (endStreamOffset >= 0) { + endStreamOffset = FindTag(FX_BSTRC("endstream"), 0); + if (endStreamOffset < 0) { + //Can't find any "endstream". + break; + } + prevMarkers = ReadEOLMarkers(streamStartPos + endStreamOffset - 1); + nextMarkers = ReadEOLMarkers(streamStartPos + endStreamOffset + ENDSTREAM_LEN); + if (prevMarkers != 0 && nextMarkers != 0) { + //Stop searching when the keyword "endstream" is found. + break; } else { - m_Pos = curPos; + unsigned char ch = 0x00; + GetCharAt(streamStartPos + endStreamOffset + ENDSTREAM_LEN, ch); + if (ch == 0x09 || ch == 0x20) { + //"endstream" is treated as a keyword + //when it is followed by a tab or whitespace + break; + } } - uint8_t byte1, byte2; - GetCharAt(StreamStartPos + offset - 1, byte1); - GetCharAt(StreamStartPos + offset - 2, byte2); - if (byte1 == 0x0a && byte2 == 0x0d) { - len -= 2; - } else if (byte1 == 0x0a || byte1 == 0x0d) { - len--; + m_Pos += ENDSTREAM_LEN; + } + m_Pos = streamStartPos; + FX_FILESIZE endObjOffset = 0; + while (endObjOffset >= 0) { + endObjOffset = FindTag(FX_BSTRC("endobj"), 0); + if (endObjOffset < 0) { + //Can't find any "endobj". + break; + } + prevMarkers = ReadEOLMarkers(streamStartPos + endObjOffset - 1); + nextMarkers = ReadEOLMarkers(streamStartPos + endObjOffset + ENDOBJ_LEN); + if (prevMarkers != 0 && nextMarkers != 0) { + //Stop searching when the keyword "endobj" is found. + break; } - len = (FX_DWORD)offset; - pDict->SetAtInteger(FX_BSTRC("Length"), len); + m_Pos += ENDOBJ_LEN; + } + if (endStreamOffset < 0 && endObjOffset < 0) { + //Can't find "endstream" or "endobj". + return nullptr; + } + if (endStreamOffset < 0 && endObjOffset >= 0) { + //Correct the position of end stream. + endStreamOffset = endObjOffset; + } else if (endStreamOffset >= 0 && endObjOffset < 0) { + //Correct the position of end obj. + endObjOffset = endStreamOffset; + } else if (endStreamOffset > endObjOffset) { + endStreamOffset = endObjOffset; + } + len = endStreamOffset; + numMarkers = ReadEOLMarkers(streamStartPos + endStreamOffset - 2); + if (numMarkers == 2) { + len -= 2; } else { - m_Pos = StreamStartPos; - if (FindTag(FX_BSTRC("endobj"), 0) < 0) { - return NULL; + numMarkers = ReadEOLMarkers(streamStartPos + endStreamOffset - 1); + if (numMarkers == 1) { + len -= 1; } } + if (len <= 0) { + return nullptr; + } + pDict->SetAtInteger(FX_BSTRC("Length"), len); } - m_Pos = StreamStartPos; + m_Pos = streamStartPos; + } + if (len <= 0) { + return nullptr; } - CPDF_Stream* pStream; uint8_t* pData = FX_Alloc(uint8_t, len); ReadBlock(pData, len); if (pCryptoHandler) { @@ -2502,14 +2571,16 @@ CPDF_Stream* CPDF_SyntaxParser::ReadStream(CPDF_Dictionary* pDict, len = dest_buf.GetSize(); dest_buf.DetachBuffer(); } - pStream = new CPDF_Stream(pData, len, pDict); + CPDF_Stream* pStream = new CPDF_Stream(pData, len, pDict); if (pContext) { pContext->m_DataEnd = pContext->m_DataStart + len; } - StreamStartPos = m_Pos; + streamStartPos = m_Pos; GetNextWord(); - if (m_WordSize == 6 && 0 == FXSYS_memcmp(m_WordBuffer, "endobj", 6)) { - m_Pos = StreamStartPos; + numMarkers = ReadEOLMarkers(m_Pos); + if (m_WordSize == ENDOBJ_LEN && numMarkers != 0 && + FXSYS_memcmp(m_WordBuffer, "endobj", ENDOBJ_LEN) == 0) { + m_Pos = streamStartPos; } return pStream; } |