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-rw-r--r--include/vcl/filter/PDFiumLibrary.hxx2
-rw-r--r--include/vcl/filter/pdfdocument.hxx6
-rw-r--r--vcl/source/filter/ipdf/pdfdocument.cxx82
-rw-r--r--vcl/source/pdf/PDFiumLibrary.cxx12
-rw-r--r--xmlsecurity/qa/unit/pdfsigning/data/bad-cert-p1.pdfbin0 -> 29646 bytes
-rw-r--r--xmlsecurity/qa/unit/pdfsigning/pdfsigning.cxx14
-rw-r--r--xmlsecurity/source/helper/pdfsignaturehelper.cxx22
7 files changed, 118 insertions, 20 deletions
diff --git a/include/vcl/filter/PDFiumLibrary.hxx b/include/vcl/filter/PDFiumLibrary.hxx
index 474f509df46b..96f258127693 100644
--- a/include/vcl/filter/PDFiumLibrary.hxx
+++ b/include/vcl/filter/PDFiumLibrary.hxx
@@ -213,7 +213,7 @@ public:
std::unique_ptr<PDFiumTextPage> getTextPage();
/// Get bitmap checksum of the page, without annotations/commenting.
- BitmapChecksum getChecksum();
+ BitmapChecksum getChecksum(int nMDPPerm);
double getWidth();
double getHeight();
diff --git a/include/vcl/filter/pdfdocument.hxx b/include/vcl/filter/pdfdocument.hxx
index be06db286d3e..de0a7b9365ff 100644
--- a/include/vcl/filter/pdfdocument.hxx
+++ b/include/vcl/filter/pdfdocument.hxx
@@ -393,6 +393,7 @@ public:
size_t GetObjectOffset(size_t nIndex) const;
const std::vector<std::unique_ptr<PDFElement>>& GetElements() const;
std::vector<PDFObjectElement*> GetPages();
+ PDFObjectElement* GetCatalog();
/// Remember the end location of an EOF token.
void PushBackEOF(size_t nOffset);
/// Look up object based on object number, possibly by parsing object streams.
@@ -420,6 +421,11 @@ public:
bool Write(SvStream& rStream);
/// Get a list of signatures embedded into this document.
std::vector<PDFObjectElement*> GetSignatureWidgets();
+ /**
+ * Get the value of the "modification detection and prevention" permission:
+ * Valid values are 1, 2 and 3: only 3 allows annotations after signing.
+ */
+ int GetMDPPerm();
/// Remove the nth signature from read document in the edit buffer.
bool RemoveSignature(size_t nPosition);
/// Get byte offsets of the end of incremental updates.
diff --git a/vcl/source/filter/ipdf/pdfdocument.cxx b/vcl/source/filter/ipdf/pdfdocument.cxx
index 2b6c9d49de34..7c085abe3324 100644
--- a/vcl/source/filter/ipdf/pdfdocument.cxx
+++ b/vcl/source/filter/ipdf/pdfdocument.cxx
@@ -2034,10 +2034,8 @@ static void visitPages(PDFObjectElement* pPages, std::vector<PDFObjectElement*>&
pPages->setVisiting(false);
}
-std::vector<PDFObjectElement*> PDFDocument::GetPages()
+PDFObjectElement* PDFDocument::GetCatalog()
{
- std::vector<PDFObjectElement*> aRet;
-
PDFReferenceElement* pRoot = nullptr;
PDFTrailerElement* pTrailer = nullptr;
@@ -2057,11 +2055,18 @@ std::vector<PDFObjectElement*> PDFDocument::GetPages()
if (!pRoot)
{
- SAL_WARN("vcl.filter", "PDFDocument::GetPages: trailer has no Root key");
- return aRet;
+ SAL_WARN("vcl.filter", "PDFDocument::GetCatalog: trailer has no Root key");
+ return nullptr;
}
- PDFObjectElement* pCatalog = pRoot->LookupObject();
+ return pRoot->LookupObject();
+}
+
+std::vector<PDFObjectElement*> PDFDocument::GetPages()
+{
+ std::vector<PDFObjectElement*> aRet;
+
+ PDFObjectElement* pCatalog = GetCatalog();
if (!pCatalog)
{
SAL_WARN("vcl.filter", "PDFDocument::GetPages: trailer has no catalog");
@@ -2134,6 +2139,71 @@ std::vector<PDFObjectElement*> PDFDocument::GetSignatureWidgets()
return aRet;
}
+int PDFDocument::GetMDPPerm()
+{
+ int nRet = 3;
+
+ std::vector<PDFObjectElement*> aSignatures = GetSignatureWidgets();
+ if (aSignatures.empty())
+ {
+ return nRet;
+ }
+
+ for (const auto& pSignature : aSignatures)
+ {
+ vcl::filter::PDFObjectElement* pSig = pSignature->LookupObject("V");
+ if (!pSig)
+ {
+ SAL_WARN("vcl.filter", "PDFDocument::GetMDPPerm: can't find signature object");
+ continue;
+ }
+
+ auto pReference = dynamic_cast<PDFArrayElement*>(pSig->Lookup("Reference"));
+ if (!pReference || pReference->GetElements().empty())
+ {
+ continue;
+ }
+
+ auto pFirstReference = dynamic_cast<PDFDictionaryElement*>(pReference->GetElements()[0]);
+ if (!pFirstReference)
+ {
+ SAL_WARN("vcl.filter",
+ "PDFDocument::GetMDPPerm: reference array doesn't contain a dictionary");
+ continue;
+ }
+
+ PDFElement* pTransformParams = pFirstReference->LookupElement("TransformParams");
+ auto pTransformParamsDict = dynamic_cast<PDFDictionaryElement*>(pTransformParams);
+ if (!pTransformParamsDict)
+ {
+ auto pTransformParamsRef = dynamic_cast<PDFReferenceElement*>(pTransformParams);
+ if (pTransformParamsRef)
+ {
+ PDFObjectElement* pTransformParamsObj = pTransformParamsRef->LookupObject();
+ if (pTransformParamsObj)
+ {
+ pTransformParamsDict = pTransformParamsObj->GetDictionary();
+ }
+ }
+ }
+
+ if (!pTransformParamsDict)
+ {
+ continue;
+ }
+
+ auto pP = dynamic_cast<PDFNumberElement*>(pTransformParamsDict->LookupElement("P"));
+ if (!pP)
+ {
+ return 2;
+ }
+
+ return pP->GetValue();
+ }
+
+ return nRet;
+}
+
std::vector<unsigned char> PDFDocument::DecodeHexString(PDFHexStringElement const* pElement)
{
return svl::crypto::DecodeHexString(pElement->GetValue());
diff --git a/vcl/source/pdf/PDFiumLibrary.cxx b/vcl/source/pdf/PDFiumLibrary.cxx
index 0b5114830c71..41e061bb1f6c 100644
--- a/vcl/source/pdf/PDFiumLibrary.cxx
+++ b/vcl/source/pdf/PDFiumLibrary.cxx
@@ -388,7 +388,7 @@ std::unique_ptr<PDFiumBitmap> PDFiumPageObject::getImageBitmap()
return pPDFiumBitmap;
}
-BitmapChecksum PDFiumPage::getChecksum()
+BitmapChecksum PDFiumPage::getChecksum(int nMDPPerm)
{
size_t nPageWidth = getWidth();
size_t nPageHeight = getHeight();
@@ -399,11 +399,15 @@ BitmapChecksum PDFiumPage::getChecksum()
return 0;
}
- // Intentionally not using FPDF_ANNOT here, annotations/commenting is OK to not affect the
- // checksum, signature verification wants this.
+ int nFlags = 0;
+ if (nMDPPerm != 3)
+ {
+ // Annotations/commenting should affect the checksum, signature verification wants this.
+ nFlags = FPDF_ANNOT;
+ }
FPDF_RenderPageBitmap(pPdfBitmap->getPointer(), mpPage, /*start_x=*/0, /*start_y=*/0,
nPageWidth, nPageHeight,
- /*rotate=*/0, /*flags=*/0);
+ /*rotate=*/0, nFlags);
Bitmap aBitmap(Size(nPageWidth, nPageHeight), 24);
{
BitmapScopedWriteAccess pWriteAccess(aBitmap);
diff --git a/xmlsecurity/qa/unit/pdfsigning/data/bad-cert-p1.pdf b/xmlsecurity/qa/unit/pdfsigning/data/bad-cert-p1.pdf
new file mode 100644
index 000000000000..04d9950582b0
--- /dev/null
+++ b/xmlsecurity/qa/unit/pdfsigning/data/bad-cert-p1.pdf
Binary files differ
diff --git a/xmlsecurity/qa/unit/pdfsigning/pdfsigning.cxx b/xmlsecurity/qa/unit/pdfsigning/pdfsigning.cxx
index 586ef54d3075..78c564b26e28 100644
--- a/xmlsecurity/qa/unit/pdfsigning/pdfsigning.cxx
+++ b/xmlsecurity/qa/unit/pdfsigning/pdfsigning.cxx
@@ -388,6 +388,20 @@ CPPUNIT_TEST_FIXTURE(PDFSigningTest, testPartialInBetween)
CPPUNIT_ASSERT(rInformation.bPartialDocumentSignature);
}
+CPPUNIT_TEST_FIXTURE(PDFSigningTest, testBadCertP1)
+{
+ std::vector<SignatureInformation> aInfos
+ = verify(m_directories.getURLFromSrc(DATA_DIRECTORY) + "bad-cert-p1.pdf", 1);
+ CPPUNIT_ASSERT(!aInfos.empty());
+ SignatureInformation& rInformation = aInfos[0];
+ // Without the accompanying fix in place, this test would have failed with:
+ // - Expected: 0 (SecurityOperationStatus_UNKNOWN)
+ // - Actual : 1 (SecurityOperationStatus_OPERATION_SUCCEEDED)
+ // i.e. annotation after a P1 signature was not considered as a bad modification.
+ CPPUNIT_ASSERT_EQUAL(xml::crypto::SecurityOperationStatus::SecurityOperationStatus_UNKNOWN,
+ rInformation.nStatus);
+}
+
/// Test writing a PAdES signature.
CPPUNIT_TEST_FIXTURE(PDFSigningTest, testSigningCertificateAttribute)
{
diff --git a/xmlsecurity/source/helper/pdfsignaturehelper.cxx b/xmlsecurity/source/helper/pdfsignaturehelper.cxx
index 3942163e970c..a1dde44aaeb7 100644
--- a/xmlsecurity/source/helper/pdfsignaturehelper.cxx
+++ b/xmlsecurity/source/helper/pdfsignaturehelper.cxx
@@ -227,7 +227,8 @@ bool IsCompleteSignature(SvStream& rStream, vcl::filter::PDFDocument& rDocument,
#if HAVE_FEATURE_PDFIUM
/// Collects the checksum of each page of one version of the PDF.
-void AnalyizeSignatureStream(SvMemoryStream& rStream, std::vector<BitmapChecksum>& rPageChecksums)
+void AnalyizeSignatureStream(SvMemoryStream& rStream, std::vector<BitmapChecksum>& rPageChecksums,
+ int nMDPPerm)
{
auto pPdfium = vcl::pdf::PDFiumLibrary::get();
vcl::pdf::PDFiumDocument aPdfDocument(
@@ -242,7 +243,7 @@ void AnalyizeSignatureStream(SvMemoryStream& rStream, std::vector<BitmapChecksum
return;
}
- BitmapChecksum nPageChecksum = pPdfPage->getChecksum();
+ BitmapChecksum nPageChecksum = pPdfPage->getChecksum(nMDPPerm);
rPageChecksums.push_back(nPageChecksum);
}
}
@@ -250,9 +251,9 @@ void AnalyizeSignatureStream(SvMemoryStream& rStream, std::vector<BitmapChecksum
/**
* Checks if incremental updates after singing performed valid modifications only.
- * Annotations/commenting is OK, other changes are not.
+ * nMDPPerm decides if annotations/commenting is OK, other changes are always not.
*/
-bool IsValidSignature(SvStream& rStream, vcl::filter::PDFObjectElement* pSignature)
+bool IsValidSignature(SvStream& rStream, vcl::filter::PDFObjectElement* pSignature, int nMDPPerm)
{
size_t nSignatureEOF = 0;
if (!GetEOFOfSignature(pSignature, nSignatureEOF))
@@ -268,7 +269,7 @@ bool IsValidSignature(SvStream& rStream, vcl::filter::PDFObjectElement* pSignatu
rStream.Seek(nPos);
aSignatureStream.Seek(0);
std::vector<BitmapChecksum> aSignedPages;
- AnalyizeSignatureStream(aSignatureStream, aSignedPages);
+ AnalyizeSignatureStream(aSignatureStream, aSignedPages, nMDPPerm);
SvMemoryStream aFullStream;
nPos = rStream.Tell();
@@ -277,7 +278,7 @@ bool IsValidSignature(SvStream& rStream, vcl::filter::PDFObjectElement* pSignatu
rStream.Seek(nPos);
aFullStream.Seek(0);
std::vector<BitmapChecksum> aAllPages;
- AnalyizeSignatureStream(aFullStream, aAllPages);
+ AnalyizeSignatureStream(aFullStream, aAllPages, nMDPPerm);
// Fail if any page looks different after signing and at the end. Annotations/commenting doesn't
// count, though.
@@ -294,7 +295,8 @@ bool IsValidSignature(SvStream& rStream, vcl::filter::PDFObjectElement* pSignatu
* @return If we can determinate a result.
*/
bool ValidateSignature(SvStream& rStream, vcl::filter::PDFObjectElement* pSignature,
- SignatureInformation& rInformation, vcl::filter::PDFDocument& rDocument)
+ SignatureInformation& rInformation, vcl::filter::PDFDocument& rDocument,
+ int nMDPPerm)
{
vcl::filter::PDFObjectElement* pValue = pSignature->LookupObject("V");
if (!pValue)
@@ -401,7 +403,7 @@ bool ValidateSignature(SvStream& rStream, vcl::filter::PDFObjectElement* pSignat
return false;
}
rInformation.bPartialDocumentSignature = !IsCompleteSignature(rStream, rDocument, pSignature);
- if (!IsValidSignature(rStream, pSignature))
+ if (!IsValidSignature(rStream, pSignature, nMDPPerm))
{
SAL_WARN("xmlsecurity.helper", "ValidateSignature: invalid incremental update detected");
return false;
@@ -451,11 +453,13 @@ bool PDFSignatureHelper::ReadAndVerifySignatureSvStream(SvStream& rStream)
m_aSignatureInfos.clear();
+ int nMDPPerm = aDocument.GetMDPPerm();
+
for (size_t i = 0; i < aSignatures.size(); ++i)
{
SignatureInformation aInfo(i);
- if (!ValidateSignature(rStream, aSignatures[i], aInfo, aDocument))
+ if (!ValidateSignature(rStream, aSignatures[i], aInfo, aDocument, nMDPPerm))
SAL_WARN("xmlsecurity.helper", "failed to determine digest match");
m_aSignatureInfos.push_back(aInfo);
generated by cgit v1.2.3 (git 2.39.1) at 2024-04-23 06:44:53 +0000