Re: [RFC v5 6/7] sprintf: Add [v]sprintf_array()

[Kees Cook <kees@kernel.org>]

On Tue, Jul 15, 2025 at 09:08:14AM +0200, Alejandro Colomar wrote:
> Hi Kees,
> 
> On Mon, Jul 14, 2025 at 10:19:39PM -0700, Kees Cook wrote:
> > On Fri, Jul 11, 2025 at 10:58:56AM -0700, Linus Torvalds wrote:
> > >         struct seq_buf s;
> > >         seq_buf_init(&s, buf, szie);
> > 
> > And because some folks didn't like this "declaration that requires a
> > function call", we even added:
> > 
> > 	DECLARE_SEQ_BUF(s, 32);
> > 
> > to do it in 1 line. :P
> > 
> > I would love to see more string handling replaced with seq_buf.
> 
> The thing is, it's not as easy as the fixes I'm proposing, and
> sprintf_end() solves a lot of UB in a minimal diff that you can dumbly
> apply.

Note that I'm not arguing against your idea -- I just think it's not
going to be likely to end up in Linux soon given Linus's objections. My
perspective is mainly one of pragmatic damage control: what *can* we do
in Linux that would make things better? Currently, seq_buf is better
than raw C strings...

-- 
Kees Cook