Re: X server startup fails on Ultra-45 with Sun XVR-100

[Michael <macallan1888%gmail.com@localhost>]

Hello,

On Wed, 18 Dec 2024 07:03:56 +1100
matthew green <mrg%eterna23.net@localhost> wrote:

> > [   149.779562] radeonfb0: autoconfiguration error: mmap() rejected.
> >
> > For completeness, kern.securelevel=1 as per default.  
> 
> i think this is exactly the problem.  netbsd/sparc64 has regressed
> (a long while ago) and needs securelevel=-1 for many cards now days.
> try a kernel with options INSECURE, unfortunately.
> 
> the failure happens when a KAUTH_MACHDEP_UNMANAGEDMEM request is
> rejected, and that happens when trying to map the non-screen memory
> for radeonfb.c.
> 
> Mac, are these registers? can they be abused to modify other kernel
> memory?  what's the specific problem here?  i see this code in many
> of the fb drivers, and the comments seem to be pre-kauth issue here,
> since it says:

There's at least one DMA engine in there, so yes it can.

>  * restrict all other mappings to processes with superuser privileges
>  * or the kernel itself
> 
> but without understanding i can't judge.

That comment is ancient and needs to go. We used to run X withe setuid
root ages ago, but that's not enough anymore :/

have fun
Michael