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Commit 53026346 authored by Florian Westphal's avatar Florian Westphal Committed by Greg Kroah-Hartman
Browse files

netfilter: nf_tables: fix memory leak during stateful obj update 



commit dad3bdeef45f81a6e90204bcc85360bb76eccec7 upstream.

stateful objects can be updated from the control plane.
The transaction logic allocates a temporary object for this purpose.

The ->init function was called for this object, so plain kfree() leaks
resources. We must call ->destroy function of the object.

nft_obj_destroy does this, but it also decrements the module refcount,
but the update path doesn't increment it.

To avoid special-casing the update object release, do module_get for
the update case too and release it via nft_obj_destroy().

Fixes: d62d0ba9 ("netfilter: nf_tables: Introduce stateful object update operation")
Cc: Fernando Fernandez Mancera <ffmancera@riseup.net>
Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 5ad5886f

net/netfilter/nf_tables_api.c

+9 −4
Original line number Diff line number Diff line
@@ -5184,12 +5184,15 @@ static int nf_tables_updobj(const struct nft_ctx *ctx, 
{

	struct nft_object *newobj;

	struct nft_trans *trans;

	int err;

	int err = -ENOMEM;



	if (!try_module_get(type->owner))

		return -ENOENT;



	trans = nft_trans_alloc(ctx, NFT_MSG_NEWOBJ,

				sizeof(struct nft_trans_obj));

	if (!trans)

		return -ENOMEM;

		goto err_trans;



	newobj = nft_obj_init(ctx, type, attr);

	if (IS_ERR(newobj)) {
@@ -5206,6 +5209,8 @@ static int nf_tables_updobj(const struct nft_ctx *ctx, 


err_free_trans:

	kfree(trans);

err_trans:

	module_put(type->owner);

	return err;

}
@@ -6544,7 +6549,7 @@ static void nft_obj_commit_update(struct nft_trans *trans) 
	if (obj->ops->update)

		obj->ops->update(obj, newobj);



	kfree(newobj);

	nft_obj_destroy(&trans->ctx, newobj);

}



static void nft_commit_release(struct nft_trans *trans)
@@ -7109,7 +7114,7 @@ static int __nf_tables_abort(struct net *net, enum nfnl_abort_action action) 
			break;

		case NFT_MSG_NEWOBJ:

			if (nft_trans_obj_update(trans)) {

				kfree(nft_trans_obj_newobj(trans));

				nft_obj_destroy(&trans->ctx, nft_trans_obj_newobj(trans));

				nft_trans_destroy(trans);

			} else {

				trans->ctx.table->use--;