[PATCH RFC] seccomp: Implement syscall isolation based on memory areas

[Matthew Wilcox]

On Sun, May 31, 2020 at 03:39:33PM +0300, Paul Gofman wrote:
> > Paul (cc'ed) is the wine expert, but my understanding is that memory
> > allocation and initial program load of the emulated binary will go
> > through wine.  It does the allocation and mark the vma accordingly
> > before returning the allocated range to the windows application.
> Yes, exactly. Pretty much any memory allocation which Wine does needs
> syscalls (if those are ever encountered later during executing code from
> those areas) to be trapped by Wine and passed to Wine's implementation
> of the corresponding Windows API function. Linux native libraries
> loading and memory allocations performed by them go outside of Wine control.

I don't like Gabriel's approach very much.  Could we do something like
issue a syscall before executing a Windows region and then issue another
syscall when exiting?  If so, we could switch the syscall entry point (ie
change MSR_LSTAR).  I'm thinking something like a personality() syscall.
But maybe that would be too high an overhead.