Re: [PATCH v17 4/5] random: introduce generic vDSO getrandom() implementation

Andy Lutomirski
2024-06-18T00:06:36Z

On Fri, Jun 14, 2024 at 12:08 PM Jason A. Donenfeld <Jason@zx2c4.com> wrote:
>
> Provide a generic C vDSO getrandom() implementation, which operates on
> an opaque state returned by vgetrandom_alloc() and produces random bytes
> the same way as getrandom(). This has a the API signature:
>
> ssize_t vgetrandom(void *buffer, size_t len, unsigned int flags, void *opaque_state);

Last time around, I mentioned some potential issues with this function
signature, and I didn't see any answer. My specific objection was to
the fact that the caller passes in a pointer but not a length, and
this potentially makes reasoning about memory safety awkward,
especially if anything like CRIU is involved.

--Andy