[tbb-dev] #25112 - Tor Browser 7.5 is not working on Windows Vista 64bit

[Richard Pospesel]

So I've tracked down the root of the problem here: we're not currently
building nor packaging wow_helper.exe with Tor Browser.  This exe is a
necessary part of the sandbox init process for Vista (but not newer
Windows OSes)

I'm able to build locally with mingw via:

	x86_64-w64-mingw32-g++ -m64 -municode -static -static-libgcc
-static-libstdc++ -I../../.. *.cc -o wow_helper.exe

Dropping that exe into the Browser folder lets sandbox'd tabs work once
more!

That said, getting this building with FF's build system and also
updating RBM to work with the new dependencies requires some specialized
knowledge I don't currently have, so any pointers on this front would be
great.

Just spit-balling, but the main hurdles as I see them are as follows:

- firefox : wow_helper is built with special Makefile.in configuration
file which temporarily overwrites the CXX, LIB and friends to point to
the 64-bit MSVC compiler toolchain.  We can probably do a similar thing
here with x86_64-w64-mingw32-g++

- rbm : need to update the docker image to install the x86_64 version of
the mingw toolchain.

- tor-browser : will need to update the nsis installer and possibly
other things to properly include and deploy the wow_helper.exe

However, Chromium removed this entire code path back in 2016 when they
dropped support for XP and Vista, and somewhere between version 52.6 and
latest this code path was also removed in Firefox.  So, depending on the
timeline for updating Tor Browser to latest, we may just want to ignore
this issue just do a simpler code patch that disables sandboxing all
together for those under Windows 7.

best,
-Richard