Re: [PATCH v2 5/6] KEYS: Reject @datalen values over INT_MAX

[Jarkko Sakkinen <jarkko@kernel.org>]

On Tue, Oct 20, 2026 at 02:55:41AM +0300, Jarkko Sakkinen wrote:
> On Tue, Oct 20, 2026 at 12:07:32AM +0300, Jarkko Sakkinen wrote:
> > On Mon, Oct 19, 2026 at 12:31:48PM -0700, Eric Biggers wrote:
> > > On Mon, Oct 19, 2026 at 09:17:25PM +0300, Jarkko Sakkinen wrote:
> > > > Protect quota from overflowing by rejecting @datalen values that
> > > > surpass over INT_MAX.
> > > 
> > > Is there an example of how this can happen, and why the limit needs to
> > > still be so large?  add_key() for example limits the payload length to
> > > 1 MiB.
> > 
> > I did a bit scavenging, and to my knowleddge, no. So I would retain
> > this as safety measure but would not consider it as a bug fix.
> 
> While it is true that add_key() has 1 MiB limit there's also
> root quota. That was what I was originally thinking about
> now that I scratched my head a bit.
> 
> But...
> 
> However, it is capped by /proc/sys/kernel/keys/root_maxbytes, 
> SYSCTL_INT_MAX already.
> 
> So that makes the check this patch adds irrelevant, and thus
> it should be dropped.
> 
> Phew... At least it is now investigated in-depth enough, I
> think.

This also makes the other safe-guard useless, so I'll drop
that too.

And likely expand the patch set to address the entry points
that you mentioned.

Br, Jarkko