Re: encrypted swap [was: The disappearing sys_call_table export.]

[Hugh Dickins]

On Sat, 17 May 2003, Yoav Weiss wrote:
> 
> Just a thought: If we encrypt per-area, it might make more sense to go
> down another level, to mm_struct.  It already has its refcount and
> backpoints its users.  The key is valid iff the mm_struct is valid anyway,
> so we may not have to track so many things ourselves.  Just allocate a
> random key whenever mm_struct is allocated, and overwrite the key before
> mm_struct is freed.  Any mm experts care to comment ?

A page of swap may belong to different mms (see fork's copy_page_range
calling swap_duplicate).  That's a difficulty for your approaches,
and one reason why cryptoloop of block device is used instead.

Hugh