From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Roman Mashak , Cong Wang , "David S. Miller" Subject: [PATCH 4.14 13/45] net sched actions: fix refcnt leak in skbmod Date: Fri, 18 May 2018 10:15:30 +0200 Message-Id: <20180518081530.998937972@linuxfoundation.org> In-Reply-To: <20180518081530.331586165@linuxfoundation.org> References: <20180518081530.331586165@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Roman Mashak [ Upstream commit a52956dfc503f8cc5cfe6454959b7049fddb4413 ] When application fails to pass flags in netlink TLV when replacing existing skbmod action, the kernel will leak refcnt: $ tc actions get action skbmod index 1 total acts 0 action order 0: skbmod pipe set smac 00:11:22:33:44:55 index 1 ref 1 bind 0 For example, at this point a buggy application replaces the action with index 1 with new smac 00:aa:22:33:44:55, it fails because of zero flags, however refcnt gets bumped: $ tc actions get actions skbmod index 1 total acts 0 action order 0: skbmod pipe set smac 00:11:22:33:44:55 index 1 ref 2 bind 0 $ Tha patch fixes this by calling tcf_idr_release() on existing actions. Fixes: 86da71b57383d ("net_sched: Introduce skbmod action") Signed-off-by: Roman Mashak Acked-by: Cong Wang Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/sched/act_skbmod.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/net/sched/act_skbmod.c +++ b/net/sched/act_skbmod.c @@ -131,8 +131,11 @@ static int tcf_skbmod_init(struct net *n if (exists && bind) return 0; - if (!lflags) + if (!lflags) { + if (exists) + tcf_idr_release(*a, bind); return -EINVAL; + } if (!exists) { ret = tcf_idr_create(tn, parm->index, est, a,