[PATCH 4.20 57/76] net/sched: act_ipt: fix refcount leak when replace fails

Greg Kroah-Hartman
2019-03-08T12:56:19Z

From: Davide Caratti <dcaratti@redhat.com>

[ Upstream commit 8f67c90ee9148eab3d2b4393c3cf76489b27f87c ]

After commit 4e8ddd7f1758 ("net: sched: don't release reference on action
overwrite"), the error path of all actions was converted to drop refcount
also when the action was being overwritten. But we forgot act_ipt_init(),
in case allocation of 'tname' was not successful:

# tc action add action xt -j LOG --log-prefix hello index 100
tablename: mangle hook: NF_IP_POST_ROUTING
target: LOG level warning prefix "hello" index 100
# tc action show action xt
total acts 1

action order 0: tablename: mangle hook: NF_IP_POST_ROUTING
target LOG level warning prefix "hello"
index 100 ref 1 bind 0
# tc action replace action xt -j LOG --log-prefix world index 100
tablename: mangle hook: NF_IP_POST_ROUTING
target: LOG level warning prefix "world" index 100
RTNETLINK answers: Cannot allocate memory
We have an error talking to the kernel
# tc action show action xt
total acts 1

action order 0: tablename: mangle hook: NF_IP_POST_ROUTING
target LOG level warning prefix "hello"
index 100 ref 2 bind 0

Ensure we call tcf_idr_release(), in case 'tname' allocation failed, also
when the action is being replaced.

Fixes: 4e8ddd7f1758 ("net: sched: don't release reference on action overwrite")
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/sched/act_ipt.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

--- a/net/sched/act_ipt.c
+++ b/net/sched/act_ipt.c
@@ -199,8 +199,7 @@ err3:
err2:
kfree(tname);
err1:
- if (ret == ACT_P_CREATED)
- tcf_idr_release(*a, bind);
+ tcf_idr_release(*a, bind);
return err;
}