include/vcl/filter/PDFiumLibrary.hxx | 30 ++++ vcl/source/pdf/PDFiumLibrary.cxx | 31 ++++ xmlsecurity/Library_xmlsecurity.mk | 5 xmlsecurity/qa/unit/signing/data/hide-and-replace-shadow-file-signed-2.pdf |binary xmlsecurity/qa/unit/signing/signing.cxx | 18 ++ xmlsecurity/source/pdfio/pdfdocument.cxx | 70 ++++++++++ xmlsecurity/workben/pdfverify.cxx | 5 7 files changed, 156 insertions(+), 3 deletions(-)
New commits: commit 3bd3fbe77ba0fb86e82f157b15f9626d586e96fa Author: Miklos Vajna <vmik...@collabora.com> AuthorDate: Fri Sep 4 17:17:48 2020 +0200 Commit: Miklos Vajna <vmik...@collabora.com> CommitDate: Fri Dec 18 13:54:19 2020 +0100 xmlsecurity: pdf incremental updates that are non-commenting are invalid I.e. it's OK to add incremental updates for annotation/commenting purposes and that doesn't invalite existing signatures. Everything else does. (cherry picked from commit 61834cd574568613f0b0a2ee099a60fa5a8d9804) Conflicts: include/vcl/filter/PDFiumLibrary.hxx vcl/source/pdf/PDFiumLibrary.cxx xmlsecurity/qa/unit/signing/signing.cxx xmlsecurity/source/pdfio/pdfdocument.cxx xmlsecurity/workben/pdfverify.cxx Change-Id: I4607c242b3c6f6b01517b02407e9e7a095e2e069 Reviewed-on: https://gerrit.libreoffice.org/c/core/+/107944 Tested-by: Jenkins CollaboraOffice <jenkinscollaboraoff...@gmail.com> Reviewed-by: Miklos Vajna <vmik...@collabora.com> diff --git a/include/vcl/filter/PDFiumLibrary.hxx b/include/vcl/filter/PDFiumLibrary.hxx index 1f6d97045088..60ece6b7cbc9 100644 --- a/include/vcl/filter/PDFiumLibrary.hxx +++ b/include/vcl/filter/PDFiumLibrary.hxx @@ -17,6 +17,9 @@ #include <memory> #include <rtl/instance.hxx> #include <vcl/dllapi.h> +#include <vcl/checksum.hxx> + +#include <fpdfview.h> namespace vcl { @@ -33,6 +36,33 @@ public: ~PDFium(); }; +class VCL_DLLPUBLIC PDFiumPage final +{ +private: + FPDF_PAGE mpPage; + +private: + PDFiumPage(const PDFiumPage&) = delete; + PDFiumPage& operator=(const PDFiumPage&) = delete; + +public: + PDFiumPage(FPDF_PAGE pPage) + : mpPage(pPage) + { + } + + ~PDFiumPage() + { + if (mpPage) + FPDF_ClosePage(mpPage); + } + + FPDF_PAGE getPointer() { return mpPage; } + + /// Get bitmap checksum of the page, without annotations/commenting. + BitmapChecksum getChecksum(); +}; + struct PDFiumLibrary : public rtl::StaticWithInit<std::shared_ptr<PDFium>, PDFiumLibrary> { std::shared_ptr<PDFium> operator()() { return std::make_shared<PDFium>(); } diff --git a/vcl/source/pdf/PDFiumLibrary.cxx b/vcl/source/pdf/PDFiumLibrary.cxx index 9d822c34642c..a8774b15bb4e 100644 --- a/vcl/source/pdf/PDFiumLibrary.cxx +++ b/vcl/source/pdf/PDFiumLibrary.cxx @@ -15,6 +15,9 @@ #include <vcl/filter/PDFiumLibrary.hxx> #include <fpdf_doc.h> +#include <vcl/bitmap.hxx> +#include <vcl/bitmapaccess.hxx> + namespace vcl { namespace pdf @@ -31,6 +34,34 @@ PDFium::PDFium() PDFium::~PDFium() { FPDF_DestroyLibrary(); } +BitmapChecksum PDFiumPage::getChecksum() +{ + size_t nPageWidth = FPDF_GetPageWidth(mpPage); + size_t nPageHeight = FPDF_GetPageHeight(mpPage); + FPDF_BITMAP pPdfBitmap = FPDFBitmap_Create(nPageWidth, nPageHeight, /*alpha=*/1); + if (!pPdfBitmap) + { + return 0; + } + + // Intentionally not using FPDF_ANNOT here, annotations/commenting is OK to not affect the + // checksum, signature verification wants this. + FPDF_RenderPageBitmap(pPdfBitmap, mpPage, /*start_x=*/0, /*start_y=*/0, nPageWidth, nPageHeight, + /*rotate=*/0, /*flags=*/0); + Bitmap aBitmap(Size(nPageWidth, nPageHeight), 24); + { + Bitmap::ScopedWriteAccess pWriteAccess(aBitmap); + const auto pPdfBuffer = static_cast<const sal_uInt8*>(FPDFBitmap_GetBuffer(pPdfBitmap)); + const int nStride = FPDFBitmap_GetStride(pPdfBitmap); + for (size_t nRow = 0; nRow < nPageHeight; ++nRow) + { + const sal_uInt8* pPdfLine = pPdfBuffer + (nStride * nRow); + pWriteAccess->CopyScanline(nRow, pPdfLine, ScanlineFormat::N32BitTcBgra, nStride); + } + } + return aBitmap.GetChecksum(); +} + } // end pdf } // end vcl diff --git a/xmlsecurity/Library_xmlsecurity.mk b/xmlsecurity/Library_xmlsecurity.mk index 22d27c717155..26d1549089c2 100644 --- a/xmlsecurity/Library_xmlsecurity.mk +++ b/xmlsecurity/Library_xmlsecurity.mk @@ -20,7 +20,10 @@ $(eval $(call gb_Library_add_defs,xmlsecurity,\ -DXMLSECURITY_DLLIMPLEMENTATION \ )) -$(eval $(call gb_Library_use_externals,xmlsecurity,boost_headers)) +$(eval $(call gb_Library_use_externals,xmlsecurity,\ + boost_headers \ + $(if $(filter PDFIUM,$(BUILD_TYPE)),pdfium) \ +)) $(eval $(call gb_Library_set_precompiled_header,xmlsecurity,$(SRCDIR)/xmlsecurity/inc/pch/precompiled_xmlsecurity)) diff --git a/xmlsecurity/qa/unit/signing/data/hide-and-replace-shadow-file-signed-2.pdf b/xmlsecurity/qa/unit/signing/data/hide-and-replace-shadow-file-signed-2.pdf new file mode 100644 index 000000000000..f2b1a71096b2 Binary files /dev/null and b/xmlsecurity/qa/unit/signing/data/hide-and-replace-shadow-file-signed-2.pdf differ diff --git a/xmlsecurity/qa/unit/signing/signing.cxx b/xmlsecurity/qa/unit/signing/signing.cxx index 265f0e5acbb0..6ea6275aaee6 100644 --- a/xmlsecurity/qa/unit/signing/signing.cxx +++ b/xmlsecurity/qa/unit/signing/signing.cxx @@ -93,6 +93,7 @@ public: void testPDFGood(); /// Test a typical PDF where the signature is bad. void testPDFBad(); + void testPDFHideAndReplace(); /// Test a typical PDF which is not signed. void testPDFNo(); #endif @@ -133,6 +134,7 @@ public: #if HAVE_FEATURE_PDFIMPORT CPPUNIT_TEST(testPDFGood); CPPUNIT_TEST(testPDFBad); + CPPUNIT_TEST(testPDFHideAndReplace); CPPUNIT_TEST(testPDFNo); #endif CPPUNIT_TEST(test96097Calc); @@ -497,6 +499,22 @@ void SigningTest::testPDFBad() CPPUNIT_ASSERT_EQUAL(static_cast<int>(SignatureState::BROKEN), static_cast<int>(pObjectShell->GetDocumentSignatureState())); } +void SigningTest::testPDFHideAndReplace() +{ + createDoc(m_directories.getURLFromSrc(DATA_DIRECTORY) + + "hide-and-replace-shadow-file-signed-2.pdf"); + SfxBaseModel* pBaseModel = dynamic_cast<SfxBaseModel*>(mxComponent.get()); + CPPUNIT_ASSERT(pBaseModel); + SfxObjectShell* pObjectShell = pBaseModel->GetObjectShell(); + CPPUNIT_ASSERT(pObjectShell); + // Without the accompanying fix in place, this test would have failed with: + // - Expected: 2 (BROKEN) + // - Actual : 6 (NOTVALIDATED_PARTIAL_OK) + // i.e. a non-commenting update after a signature was not marked as invalid. + CPPUNIT_ASSERT_EQUAL(static_cast<int>(SignatureState::BROKEN), + static_cast<int>(pObjectShell->GetDocumentSignatureState())); +} + void SigningTest::testPDFNo() { createDoc(m_directories.getURLFromSrc(DATA_DIRECTORY) + "no.pdf"); diff --git a/xmlsecurity/source/pdfio/pdfdocument.cxx b/xmlsecurity/source/pdfio/pdfdocument.cxx index 8d6aeafdd9f3..21ea3c324d1a 100644 --- a/xmlsecurity/source/pdfio/pdfdocument.cxx +++ b/xmlsecurity/source/pdfio/pdfdocument.cxx @@ -13,6 +13,9 @@ #include <memory> #include <vector> +#include <config_features.h> + +#include <vcl/filter/PDFiumLibrary.hxx> #include <com/sun/star/uno/Sequence.hxx> #include <comphelper/processfactory.hxx> @@ -34,6 +37,7 @@ #include <svl/sigstruct.hxx> #include <svl/cryptosign.hxx> +#include <vcl/bitmap.hxx> #ifdef XMLSEC_CRYPTO_NSS #include <cert.h> @@ -162,6 +166,67 @@ bool IsCompleteSignature(SvStream& rStream, vcl::filter::PDFDocument& rDocument, size_t nFileEnd = rStream.Tell(); return std::find(rAllEOFs.begin(), rAllEOFs.end(), nFileEnd) != rAllEOFs.end(); } + +/// Collects the checksum of each page of one version of the PDF. +void AnalyizeSignatureStream(SvMemoryStream& rStream, std::vector<BitmapChecksum>& rPageChecksums) +{ +#if HAVE_FEATURE_PDFIUM + auto pPdfium = vcl::pdf::PDFiumLibrary::get(); + FPDF_DOCUMENT pPdfDocument( + FPDF_LoadMemDocument(rStream.GetData(), rStream.GetSize(), /*password=*/nullptr)); + + int nPageCount = FPDF_GetPageCount(pPdfDocument); + for (int nPage = 0; nPage < nPageCount; ++nPage) + { + auto pPdfPage = std::make_unique<vcl::pdf::PDFiumPage>(FPDF_LoadPage(pPdfDocument, nPage)); + if (!pPdfPage) + { + return; + } + + BitmapChecksum nPageChecksum = pPdfPage->getChecksum(); + rPageChecksums.push_back(nPageChecksum); + } + FPDF_CloseDocument(pPdfDocument); +#else + (void)rStream; +#endif +} + +/** + * Checks if incremental updates after singing performed valid modifications only. + * Annotations/commenting is OK, other changes are not. + */ +bool IsValidSignature(SvStream& rStream, vcl::filter::PDFObjectElement* pSignature) +{ + size_t nSignatureEOF = 0; + if (!GetEOFOfSignature(pSignature, nSignatureEOF)) + { + return false; + } + + SvMemoryStream aSignatureStream; + sal_uInt64 nPos = rStream.Tell(); + rStream.Seek(0); + aSignatureStream.WriteStream(rStream, nSignatureEOF); + rStream.Seek(nPos); + aSignatureStream.Seek(0); + std::vector<BitmapChecksum> aSignedPages; + AnalyizeSignatureStream(aSignatureStream, aSignedPages); + + SvMemoryStream aFullStream; + nPos = rStream.Tell(); + rStream.Seek(0); + aFullStream.WriteStream(rStream); + rStream.Seek(nPos); + aFullStream.Seek(0); + std::vector<BitmapChecksum> aAllPages; + AnalyizeSignatureStream(aFullStream, aAllPages); + + // Fail if any page looks different after signing and at the end. Annotations/commenting doesn't + // count, though. + return aSignedPages == aAllPages; +} } namespace xmlsecurity @@ -272,6 +337,11 @@ bool ValidateSignature(SvStream& rStream, vcl::filter::PDFObjectElement* pSignat return false; } rInformation.bPartialDocumentSignature = !IsCompleteSignature(rStream, rDocument, pSignature); + if (!IsValidSignature(rStream, pSignature)) + { + SAL_WARN("xmlsecurity.pdfio", "ValidateSignature: invalid incremental update detected"); + return false; + } // At this point there is no obviously missing info to validate the // signature. diff --git a/xmlsecurity/workben/pdfverify.cxx b/xmlsecurity/workben/pdfverify.cxx index 7ddb2623944c..92429864080b 100644 --- a/xmlsecurity/workben/pdfverify.cxx +++ b/xmlsecurity/workben/pdfverify.cxx @@ -20,6 +20,7 @@ #include <vcl/pngwrite.hxx> #include <vcl/svapp.hxx> #include <vcl/graphicfilter.hxx> +#include <comphelper/scopeguard.hxx> #include <pdfio/pdfdocument.hxx> @@ -72,11 +73,11 @@ int pdfVerify(int nArgc, char** pArgv) uno::Reference<lang::XMultiServiceFactory> xMultiServiceFactory(xMultiComponentFactory, uno::UNO_QUERY); comphelper::setProcessServiceFactory(xMultiServiceFactory); + InitVCL(); + comphelper::ScopeGuard g([] { DeInitVCL(); }); if (nArgc > 3 && OString(pArgv[3]) == "-p") { - InitVCL(); generatePreview(pArgv[1], pArgv[2]); - DeInitVCL(); return 0; } _______________________________________________ Libreoffice-commits mailing list libreoffice-comm...@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/libreoffice-commits