[Libreoffice-commits] core.git: xmlsecurity/source
Miklos Vajna
vmiklos at collabora.co.uk
Thu Nov 10 14:10:04 UTC 2016
xmlsecurity/source/pdfio/pdfdocument.cxx | 192 ++++++++++++++++---------------
1 file changed, 105 insertions(+), 87 deletions(-)
New commits:
commit bec9e673ad37e86cbc86d0ed844340ab080a7c5f
Author: Miklos Vajna <vmiklos at collabora.co.uk>
Date: Thu Nov 10 10:33:02 2016 +0100
xmlsecurity PDF verify: fix reading multiple subsections from an xref stream
This is especially needed, as we don't bother compressing updated
objects into sections on signing, we simply use a separate section for
each updated object.
Work towards supporting xref streams and incremental updates at the same
time.
Change-Id: Ie9759edbba816991615fafc6602cdd440141b989
diff --git a/xmlsecurity/source/pdfio/pdfdocument.cxx b/xmlsecurity/source/pdfio/pdfdocument.cxx
index f3b55a8..58aac94 100644
--- a/xmlsecurity/source/pdfio/pdfdocument.cxx
+++ b/xmlsecurity/source/pdfio/pdfdocument.cxx
@@ -1265,7 +1265,7 @@ bool PDFDocument::Read(SvStream& rStream)
SAL_INFO("xmlsecurity.pdfio", "PDFDocument::Read: nStartXRef is " << nStartXRef);
if (nStartXRef == 0)
{
- SAL_WARN("xmlsecurity.pdfio", "PDFDocument::Read: found no xref statrt offset");
+ SAL_WARN("xmlsecurity.pdfio", "PDFDocument::Read: found no xref start offset");
return false;
}
while (true)
@@ -1466,37 +1466,49 @@ void PDFDocument::ReadXRefStream(SvStream& rStream)
// Look up the first and the last entry we need to read.
auto pIndex = dynamic_cast<PDFArrayElement*>(pObject->Lookup("Index"));
- size_t nFirstObject = 0;
- size_t nNumberOfObjects = 0;
- if (!pIndex || pIndex->GetElements().size() < 2)
+ std::vector<size_t> aFirstObjects;
+ std::vector<size_t> aNumberOfObjects;
+ if (!pIndex)
{
auto pSize = dynamic_cast<PDFNumberElement*>(pObject->Lookup("Size"));
if (pSize)
- nNumberOfObjects = pSize->GetValue();
+ {
+ aFirstObjects.push_back(0);
+ aNumberOfObjects.push_back(pSize->GetValue());
+ }
else
{
- SAL_WARN("xmlsecurity.pdfio", "PDFDocument::ReadXRefStream: Index not found or has < 2 elements");
+ SAL_WARN("xmlsecurity.pdfio", "PDFDocument::ReadXRefStream: Index and Size not found");
return;
}
}
else
{
const std::vector<PDFElement*>& rIndexElements = pIndex->GetElements();
- auto pFirstObject = dynamic_cast<PDFNumberElement*>(rIndexElements[0]);
- if (!pFirstObject)
+ size_t nFirstObject = 0;
+ for (size_t i = 0; i < rIndexElements.size(); ++i)
{
- SAL_WARN("xmlsecurity.pdfio", "PDFDocument::ReadXRefStream: Index has no first object");
- return;
- }
- nFirstObject = pFirstObject->GetValue();
+ if (i % 2 == 0)
+ {
+ auto pFirstObject = dynamic_cast<PDFNumberElement*>(rIndexElements[i]);
+ if (!pFirstObject)
+ {
+ SAL_WARN("xmlsecurity.pdfio", "PDFDocument::ReadXRefStream: Index has no first object");
+ return;
+ }
+ nFirstObject = pFirstObject->GetValue();
+ continue;
+ }
- auto pNumberOfObjects = dynamic_cast<PDFNumberElement*>(rIndexElements[1]);
- if (!pNumberOfObjects)
- {
- SAL_WARN("xmlsecurity.pdfio", "PDFDocument::ReadXRefStream: Index has no number of objects");
- return;
+ auto pNumberOfObjects = dynamic_cast<PDFNumberElement*>(rIndexElements[i]);
+ if (!pNumberOfObjects)
+ {
+ SAL_WARN("xmlsecurity.pdfio", "PDFDocument::ReadXRefStream: Index has no number of objects");
+ return;
+ }
+ aFirstObjects.push_back(nFirstObject);
+ aNumberOfObjects.push_back(pNumberOfObjects->GetValue());
}
- nNumberOfObjects = pNumberOfObjects->GetValue();
}
// Look up the format of a single entry.
@@ -1529,89 +1541,95 @@ void PDFDocument::ReadXRefStream(SvStream& rStream)
}
aStream.Seek(0);
- // This is the line as read from the stream.
- std::vector<unsigned char> aOrigLine(nLineLength);
- // This is the line as it appears after tweaking according to nPredictor.
- std::vector<unsigned char> aFilteredLine(nLineLength);
- for (size_t nEntry = 0; nEntry < nNumberOfObjects; ++nEntry)
+ for (size_t nSubSection = 0; nSubSection < aFirstObjects.size(); ++nSubSection)
{
- size_t nIndex = nFirstObject + nEntry;
+ size_t nFirstObject = aFirstObjects[nSubSection];
+ size_t nNumberOfObjects = aNumberOfObjects[nSubSection];
- aStream.ReadBytes(aOrigLine.data(), aOrigLine.size());
- if (aOrigLine[0] + 10 != nPredictor)
+ // This is the line as read from the stream.
+ std::vector<unsigned char> aOrigLine(nLineLength);
+ // This is the line as it appears after tweaking according to nPredictor.
+ std::vector<unsigned char> aFilteredLine(nLineLength);
+ for (size_t nEntry = 0; nEntry < nNumberOfObjects; ++nEntry)
{
- SAL_WARN("xmlsecurity.pdfio", "PDFDocument::ReadXRefStream: in-stream predictor is inconsistent with /DecodeParms/Predictor for object #" << nIndex);
- return;
- }
+ size_t nIndex = nFirstObject + nEntry;
- for (int i = 0; i < nLineLength; ++i)
- {
- switch (nPredictor)
+ aStream.ReadBytes(aOrigLine.data(), aOrigLine.size());
+ if (aOrigLine[0] + 10 != nPredictor)
{
- case 1:
- // No prediction.
- break;
- case 12:
- // PNG prediction: up (on all rows).
- aFilteredLine[i] = aFilteredLine[i] + aOrigLine[i];
- break;
- default:
- SAL_WARN("xmlsecurity.pdfio", "PDFDocument::ReadXRefStream: unexpected predictor: " << nPredictor);
+ SAL_WARN("xmlsecurity.pdfio", "PDFDocument::ReadXRefStream: in-stream predictor is inconsistent with /DecodeParms/Predictor for object #" << nIndex);
return;
- break;
}
- }
- // First character is already handled above.
- int nPos = 1;
- size_t nType = 0;
- // Start of the current field in the stream data.
- int nOffset = nPos;
- for (; nPos < nOffset + aW[0]; ++nPos)
- {
- unsigned char nCh = aFilteredLine[nPos];
- nType = (nType << 8) + nCh;
- }
-
- // Start of the object in the file stream.
- size_t nStreamOffset = 0;
- nOffset = nPos;
- for (; nPos < nOffset + aW[1]; ++nPos)
- {
- unsigned char nCh = aFilteredLine[nPos];
- nStreamOffset = (nStreamOffset << 8) + nCh;
- }
-
- // Generation number of the object.
- size_t nGenerationNumber = 0;
- nOffset = nPos;
- for (; nPos < nOffset + aW[2]; ++nPos)
- {
- unsigned char nCh = aFilteredLine[nPos];
- nGenerationNumber = (nGenerationNumber << 8) + nCh;
- }
-
- // Ignore invalid nType.
- if (nType <= 2)
- {
- if (m_aXRef.find(nIndex) == m_aXRef.end())
+ for (int i = 0; i < nLineLength; ++i)
{
- XRefEntry aEntry;
- switch (nType)
+ switch (nPredictor)
{
- case 0:
- aEntry.m_eType = XRefEntryType::FREE;
- break;
case 1:
- aEntry.m_eType = XRefEntryType::NOT_COMPRESSED;
+ // No prediction.
break;
- case 2:
- aEntry.m_eType = XRefEntryType::COMPRESSED;
+ case 12:
+ // PNG prediction: up (on all rows).
+ aFilteredLine[i] = aFilteredLine[i] + aOrigLine[i];
+ break;
+ default:
+ SAL_WARN("xmlsecurity.pdfio", "PDFDocument::ReadXRefStream: unexpected predictor: " << nPredictor);
+ return;
break;
}
- aEntry.m_nOffset = nStreamOffset;
- aEntry.m_nGenerationNumber = nGenerationNumber;
- m_aXRef[nIndex] = aEntry;
+ }
+
+ // First character is already handled above.
+ int nPos = 1;
+ size_t nType = 0;
+ // Start of the current field in the stream data.
+ int nOffset = nPos;
+ for (; nPos < nOffset + aW[0]; ++nPos)
+ {
+ unsigned char nCh = aFilteredLine[nPos];
+ nType = (nType << 8) + nCh;
+ }
+
+ // Start of the object in the file stream.
+ size_t nStreamOffset = 0;
+ nOffset = nPos;
+ for (; nPos < nOffset + aW[1]; ++nPos)
+ {
+ unsigned char nCh = aFilteredLine[nPos];
+ nStreamOffset = (nStreamOffset << 8) + nCh;
+ }
+
+ // Generation number of the object.
+ size_t nGenerationNumber = 0;
+ nOffset = nPos;
+ for (; nPos < nOffset + aW[2]; ++nPos)
+ {
+ unsigned char nCh = aFilteredLine[nPos];
+ nGenerationNumber = (nGenerationNumber << 8) + nCh;
+ }
+
+ // Ignore invalid nType.
+ if (nType <= 2)
+ {
+ if (m_aXRef.find(nIndex) == m_aXRef.end())
+ {
+ XRefEntry aEntry;
+ switch (nType)
+ {
+ case 0:
+ aEntry.m_eType = XRefEntryType::FREE;
+ break;
+ case 1:
+ aEntry.m_eType = XRefEntryType::NOT_COMPRESSED;
+ break;
+ case 2:
+ aEntry.m_eType = XRefEntryType::COMPRESSED;
+ break;
+ }
+ aEntry.m_nOffset = nStreamOffset;
+ aEntry.m_nGenerationNumber = nGenerationNumber;
+ m_aXRef[nIndex] = aEntry;
+ }
}
}
}
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