[PATCH] keys: Fix overwrite of key expiration on instantiation

[Jarkko Sakkinen]

On Tue Mar 19, 2024 at 1:27 AM EET, Jarkko Sakkinen wrote:
> On Fri Mar 15, 2024 at 9:05 PM EET, Silvio Gissi wrote:
> > The expiry time of a key is unconditionally overwritten during
> > instantiation, defaulting to turn it permanent. This causes a problem
> > for DNS resolution as the expiration set by user-space is overwritten to
> > TIME64_MAX, disabling further DNS updates. Fix this by restoring the
> > condition that key_set_expiry is only called when the pre-parser sets a
> > specific expiry.
> >
> > Fixes: 39299bdd2546 ("keys, dns: Allow key types (eg. DNS) to be reclaimed immediately on expiry")
> > Signed-off-by: Silvio Gissi <sifonsec at amazon.com>
> > cc: David Howells <dhowells at redhat.com>
> > cc: Hazem Mohamed Abuelfotoh <abuehaze at amazon.com>
> > cc: linux-afs at lists.infradead.org
> > cc: linux-cifs at vger.kernel.org
> > cc: keyrings at vger.kernel.org
> > cc: netdev at vger.kernel.org
> > cc: stable at vger.kernel.org
> > ---
> >  security/keys/key.c | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/security/keys/key.c b/security/keys/key.c
> > index 560790038329..0aa5f01d16ff 100644
> > --- a/security/keys/key.c
> > +++ b/security/keys/key.c
> > @@ -463,7 +463,8 @@ static int __key_instantiate_and_link(struct key *key,
> >  			if (authkey)
> >  				key_invalidate(authkey);
> >  
> > -			key_set_expiry(key, prep->expiry);
> > +			if (prep->expiry != TIME64_MAX)
> > +				key_set_expiry(key, prep->expiry);
> >  		}
> >  	}
> >  
>
> I checked the original commit and reflected to the fix:
>
> Reviewed-by: Jarkko Sakkinen <jarkko at kernel.org>
>
> David, I can pick this one too as I'm anyway sending PR for rc2?
>
> [1] https://lore.kernel.org/keyrings/CZX77XLG67HZ.UAU4NUQO27JP@kernel.org/

I've applied this to my tree. Can drop on request but otherwise
including to rc2 PR.

BR, Jarkko