Subject: Re: [devel-ipsec] Re: [PATCH ipsec-next 4/6] xfrm: add XFRM_MSG_MIGRATE_STATE for single SA migration

From: Simon Horman <[email-masked]>
Date: Thu, 15 Jan 2026 13:44:50 +0000

On Wed, Jan 14, 2026 at 05:09:20PM +0100, Antony Antony wrote:

Hi Antony,

> Hi Simon,
> 
> On Tue, Jan 13, 2026 at 02:57:16PM +0000, Simon Horman via Devel wrote:
> > On Fri, Jan 09, 2026 at 02:38:05PM +0100, Antony Antony wrote:

...

> > > +static int xfrm_send_migrate_state(const struct xfrm_user_migrate_state *um,
> > > +				   const struct xfrm_encap_tmpl *encap,
> > > +				   const struct xfrm_user_offload *xuo)
> > > +{
> > > +	int err;
> > > +	struct sk_buff *skb;
> > > +	struct net *net = &init_net;
> > > +
> > > +	skb = nlmsg_new(xfrm_migrate_state_msgsize(!!encap, !!xuo), GFP_ATOMIC);
> > > +	if (!skb)
> > > +		return -ENOMEM;
> > > +
> > > +	err = build_migrate_state(skb, um, encap, xuo);
> > > +	if (err < 0) {
> > > +		WARN_ON(1);
> > > +		return err;
> > 
> > skb seems to be leaked here.
> > 
> > Also flagged by Review Prompts.
> 
> I don't see a skb leak. It also looks similar to the functions above.

xfrm_get_ae() is the previous caller of nlmsg_new() in this file.
It calls BUG_ON() on error, so leaking is not an issue there.

The caller before that is xfrm_get_default() which calls kfree_skb() in
it's error path. Maybe I'm missing something obvious, but I was thinking
that approach is appropriate here too.

...