tdf#105844 package,sfx2: wholesome ODF package wrapping encryption

Redo the ODF encryption by storing an ODF package and wrapping it as a
stream "encrypted-package" in another ODF package, such that there is
only one encrypted stream - this requires only one KDF computation.

* This is only enabled in Experimental mode for now.

* Avoid storing unencrypted data in the pTempFile of SfxMedium, as it
is usually created in the same directory as the target file, which
may be on a network share or similar less trusted location.

* SfxMedium::SetEncryptionDataToStorage_Impl() should just set an
error status if it fails (how can it fail anyway)

* when loading a document, SfxDocPasswordVerifier extracts an encrypted
inner package (by calling SfxMedium::TryEncryptedInnerPackage())

* SfxMedium::GetStorage() automatically decrypts an encrypted inner
storage and sets it as the SfxMedium's xStorage

* when storing a document, SfxObjectShell::SaveTo_Impl() creates
the wrapped storages

* One challenge is to keep the macro/scripting signature working; this
can only be put in the inner storage, whereas the document signature
should continue to be on the outer storage; also it must use a Zip
storage, to see the "META-INF" directory.  This needs a new
SfxMedium::GetScriptingStorageToSign_Impl() and changes in
SfxMedium::SignContents_Impl().

Change-Id: Ibfee36ce3a9cd030f2aa2ce1484b6d001cba2389
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/160401
Tested-by: Jenkins
Reviewed-by: Michael Stahl <michael.stahl@allotropia.de>

1 files changed, 5 insertions, 1 deletions

diff --git a/include/sfx2/docfile.hxx b/include/sfx2/docfile.hxx
index 377bab62830f..fb8039f6b8f1 100644
--- a/include/sfx2/docfile.hxx
+++ b/include/sfx2/docfile.hxx
@@ -70,7 +70,7 @@ class SFX2_DLLPUBLIC SfxMedium final : public SvRefBase
     SAL_DLLPRIVATE void CloseOutStream_Impl();
     SAL_DLLPRIVATE void CloseStreams_Impl(bool bInDestruction = false);
 
-    SAL_DLLPRIVATE void SetEncryptionDataToStorage_Impl();
+    SAL_DLLPRIVATE bool SetEncryptionDataToStorage_Impl();
 
 public:
 
@@ -218,10 +218,14 @@ public:
     SAL_DLLPRIVATE OUString const & GetBackup_Impl();
 
     SAL_DLLPRIVATE css::uno::Reference< css::embed::XStorage > const & GetZipStorageToSign_Impl( bool bReadOnly = true );
+    SAL_DLLPRIVATE css::uno::Reference<css::embed::XStorage> GetScriptingStorageToSign_Impl();
     SAL_DLLPRIVATE void CloseZipStorage_Impl();
 
     // the storage that will be returned by the medium on GetStorage request
     SAL_DLLPRIVATE void SetStorage_Impl( const css::uno::Reference< css::embed::XStorage >& xNewStorage );
+    SAL_DLLPRIVATE void SetInnerStorage_Impl(const css::uno::Reference<css::embed::XStorage>& xStorage);
+    SAL_DLLPRIVATE css::uno::Reference<css::embed::XStorage>
+        TryEncryptedInnerPackage(css::uno::Reference<css::embed::XStorage> xStorage);
 
     SAL_DLLPRIVATE void CloseAndReleaseStreams_Impl();
     SAL_DLLPRIVATE void AddVersion_Impl( css::util::RevisionTag& rVersion );