Re: alloca() in kernel code

[Joerg Sonnenberger <joerg%bec.de@localhost>]

On Sat, Oct 12, 2019 at 08:13:25PM +0200, Johnny Billquist wrote:
> On 2019-10-12 19:01, Emmanuel Dreyfus wrote:
> > Mouse <mouse%Rodents-Montreal.ORG@localhost> wrote:
> > 
> > > I'm presumably missing something here, but what?
> > 
> > I suspect Maxime's concern is about uncontrolled stack-based variable
> > buffer, which could be used to crash the kernel.
> > 
> > But in my case, the data is coming from the bootloader. I cannot think
> > about a scenario where it makes sense to defend against an attack from
> > the bootloader. The kernel already has absolute trust in the bootloader.
> 
> On this one, I agree with Maxime.
> 
> Even if it comes from the bootloader, why would you want to use alloca()?

Because as Emmanuel wrote initially, dynamic allocations might not be
possible yet.

Joerg