CVS commit: src/sys/uvm

["Taylor R Campbell" <riastradh%netbsd.org@localhost>]

Module Name:    src
Committed By:   riastradh
Date:           Sat May  9 21:50:39 UTC 2020

Modified Files:
        src/sys/uvm: uvm_swap.c

Log Message:
Implement swap encryption.

Enabled by sysctl -w vm.swap_encrypt=1.  Key is generated lazily when
we first need to swap a page.  Key is chosen independently for each
swap device.  The ith swap page is encrypted with AES256-CBC using
AES256_k(le32enc(i) || 0^96) as the initialization vector.  Can be
changed at any time; no need for compatibility with on-disk formats.
Costs one bit of memory per page in each swapdev, plus a few hundred
bytes per swapdev to store the expanded AES key.

Shoulda done this decades ago!  Plan to enable this by default;
performance impact is unlikely to matter because it only happens when
you're already swapping anyway.  Much easier to set up than cgd, so
we can rip out all the documentation about carefully setting up
random-keyed cgd at the right time.


To generate a diff of this commit:
cvs rdiff -u -r1.186 -r1.187 src/sys/uvm/uvm_swap.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.