Re: Explicit pointer provenance APIs for CHERI

On Fri, 19 Jun 2026 at 07:19, Brooks Davis <[email protected]> wrote:
>
> As part of our effort to bring CHERI memory safety to FreeBSD, I have
> posted a stack of reviews in Phabricator which add APIs to explicitly
> indicate that pointer provenance should be preserved or stripped when
> copying memory.  Under CHERI targets, the non-preserving APIs explicitly
> strip validity tags from CHERI capabilities.  This limits the
> opportunity for inappropriate flow of capabilities, primarily between
> user space and kernel space.

hi!

My main feedback here is that "pointer provenance" is not defined anywhere
in both this email or the diff contents (especially manpages.)

Although I've been in developer IRC chats long enough to know what/where
to go look to figure it out, I do think that as part of landing any of
this in -HEAD
we should write up some documentation in -HEAD somewhere.

Specifically, I'd like a manpage which defines something top level for these
terms and link to that manpage from manpages that talk about pointer
provenance and anything else that leads into CHERI related stuff.



-adrian