From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 67493C433EF for ; Mon, 21 Feb 2022 12:31:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1358001AbiBUMcU (ORCPT ); Mon, 21 Feb 2022 07:32:20 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:43978 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1357974AbiBUMcT (ORCPT ); Mon, 21 Feb 2022 07:32:19 -0500 Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [IPv6:2a0a:51c0:0:12e:520::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 28308DFCE for ; Mon, 21 Feb 2022 04:31:56 -0800 (PST) Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.92) (envelope-from ) id 1nM7r7-0000f2-MR; Mon, 21 Feb 2022 13:31:53 +0100 From: Florian Westphal To: Cc: Florian Westphal , Fernando Fernandez Mancera Subject: [PATCH v3] netfilter: nf_tables: fix memory leak during stateful obj update Date: Mon, 21 Feb 2022 13:31:49 +0100 Message-Id: <20220221123149.11519-1-fw@strlen.de> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org 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: d62d0ba97b58 ("netfilter: nf_tables: Introduce stateful object update operation") Cc: Fernando Fernandez Mancera Signed-off-by: Florian Westphal --- v3: increment module refcount -> no need for special release function. net/netfilter/nf_tables_api.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 3081c4399f10..49060f281342 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -6553,10 +6553,13 @@ static int nf_tables_updobj(const struct nft_ctx *ctx, struct nft_trans *trans; int err; + 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)) { @@ -6573,6 +6576,8 @@ static int nf_tables_updobj(const struct nft_ctx *ctx, err_free_trans: kfree(trans); +err_trans: + module_put(type->owner); return err; } @@ -8185,7 +8190,7 @@ 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) @@ -8976,7 +8981,7 @@ 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--; -- 2.34.1