office-gobmx/xmlsecurity
Michael Stahl f0fda7ad22 tdf#105844 offapi,package,sfx2,xmlsecurity: add AEAD w/ AES GCM
... and use it in the new experimental ODF encryption mode.

https://www.w3.org/TR/xmlenc-core1/#sec-AES-GCM

Unfortunately it turned out that NSS PK11_CipherOp() does not work with
CKM_AES_GCM because it is initialized with "context->multi = PR_FALSE"
in sftk_CryptInit(), so the one-step functions PK11_Encrypt() and
PK11_Decrypt() have to be used.

NSS 3.52 also changed a parameter struct definition - see
https://fedoraproject.org/wiki/Changes/NssGCMParams - which is not a
problem for RHEL or SUSE system NSS since those are rebased, but it
is likely a problem for less well maintained Ubuntu LTS, so use
the old struct definition which evidently still works with NSS 3.94.

NSS 3.52 also added a new PK11_AEADOp() API but it looks like this
doesn't support incremental encryption either.

Change-Id: Ibd4a672db74b65b1218926ba35ff8d2f70444c7e
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/160505
Tested-by: Jenkins
Reviewed-by: Michael Stahl <michael.stahl@allotropia.de>
2023-12-11 20:46:40 +01:00
..
doc
inc simplify and modernise ScopedBitmapAccess 2023-12-07 09:32:14 +01:00
qa
source tdf#105844 offapi,package,sfx2,xmlsecurity: add AEAD w/ AES GCM 2023-12-11 20:46:40 +01:00
test_docs
uiconfig/ui
util
workben
AllLangMoTarget_xsc.mk
CppunitTest_qa_certext.mk
CppunitTest_xmlsecurity_dialogs_test.mk
CppunitTest_xmlsecurity_pdfsigning.mk
CppunitTest_xmlsecurity_signing.mk
CppunitTest_xmlsecurity_signing2.mk
Executable_pdfverify.mk
IwyuFilter_xmlsecurity.yaml
Library_xmlsecurity.mk
Library_xsec_xmlsec.mk
Makefile
Module_xmlsecurity.mk
README.md
UIConfig_xmlsec.mk

Document Signing

Introduction

This code provides dialogs, and infrastructure wrapping libxmlsec and gpgme that implements document signing.

For signing a document, a personal key pair is used, which consists of a private key and a public key, which is added to the document in addition to the digital signature of the document, when signing it.

The document signing can be done both for the source ODF/OOXML files and the exported PDF files. It is also possible to sign existing PDF files.

Module Contents

  • doc: OpenDocument workflow legacy information with some illustrations to have an idea of the workflow, for starters check doc/OpenDocumentSignatures-Workflow.odt.
  • inc: Headers to a subset of source files inside the module, parts like source/framework have headers inside the folder.
  • qa: Unit tests for signing and shell scripts for certificates creation for testing.
  • test_docs: Documents & certificates used for testing.
  • source: More on that below.
  • uiconfig: User interface configuration for different dialogs, it is recommended to navigate from relevant source file to the .ui file linked in the class which will be under uiconfig/ui.
  • util: UNO passive registration config for GPG/ NSS.

Source Primary Contents

  • component: Main implementation of DocumentDigitalSignatures where the interaction with security environment and certificates occur.
  • dialogs: Certificate & Signatures management dialogs.
    • certificatechooser: Dialog that allows you to find and choose certificates or signatures for encryption.
    • certificateviewer: More detailed information about each certificate.
    • digitalsignaturesdialog: Main window for signatures of the documents and the start point of signing document.
  • framework: Various elements for verifying signatures and running security engine.
  • gpg: The implementation of encrypting with GPG and security environment initialization.
  • helper: Some helper classes that include signatures manager and the helpers for PDF signing, UriBinding, and XML signatures. It also include helper tools for XSecurityEnvironment.
  • xmlsec: XML, NSS, MSCrypt encryption/ signing tools, more on the low-level side of actual implementation of algorithms.

PDF Testing

To test the signed PDFs, one can use the pdfverify in this way:

./bin/run pdfverify $PWD/xmlsecurity/qa/unit/pdfsigning/data/2good.pdf

The file parameter should be an absolute path.

This is the output of pdfverify for 2good.pdf:

verifying signatures
found 2 signatures
signature #0: digest match? 1
signature #0: partial? 0
signature #1: digest match? 1
signature #1: partial? 0

References