From: Florian Westphal <fw@strlen.de>
To: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: Florian Westphal <fw@strlen.de>,
netfilter-devel@vger.kernel.org,
Fernando Fernandez Mancera <ffmancera@riseup.net>
Subject: Re: [PATCH v2 nf] netfilter: nf_tables: fix memory leak during stateful obj update
Date: Mon, 21 Feb 2022 11:46:35 +0100 [thread overview]
Message-ID: <20220221104635.GB18967@breakpoint.cc> (raw)
In-Reply-To: <YhNqmSBAt2IRbYx6@salvia>
Pablo Neira Ayuso <pablo@netfilter.org> wrote:
> On Sun, Feb 20, 2022 at 12:18:50PM +0100, Florian Westphal wrote:
> > stateful objects can be updated from the control plane.
> > The transaction logic allocates a temporary object for this purpose.
> >
> > This object has to be released via nft_obj_destroy, not kfree, since
> > the ->init function was called and it can have side effects beyond
> > memory allocation.
> >
> > Unlike normal NEWOBJ path, the objects module refcount isn't
> > incremented, so add nft_newobj_destroy and use that.
>
> Probably this? .udata and .key is NULL for the update path so kfree
> should be fine.
Yes, that works too.
We could also ...
> - module_put(obj->ops->type->owner);
> + /* nf_tables_updobj does not increment module refcount */
> + if (!update)
> + module_put(obj->ops->type->owner);
> +
Increment the refcount for update case as well to avoid the special
case?
next prev parent reply other threads:[~2022-02-21 11:12 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-20 11:18 [PATCH v2 nf] netfilter: nf_tables: fix memory leak during stateful obj update Florian Westphal
2022-02-21 10:34 ` Pablo Neira Ayuso
2022-02-21 10:46 ` Florian Westphal [this message]
2022-02-21 10:59 ` Florian Westphal
2022-02-21 11:39 ` Pablo Neira Ayuso
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