From b91d9036883793122cf6575ca4dfbfbdd201a83d Mon Sep 17 00:00:00 2001 From: Taehee Yoo Date: Fri, 4 Jan 2019 17:56:16 +0900 Subject: [PATCH] netfilter: nf_tables: fix leaking object reference count There is no code that decreases the reference count of stateful objects in error path of the nft_add_set_elem(). this causes a leak of reference count of stateful objects. Test commands: $nft add table ip filter $nft add counter ip filter c1 $nft add map ip filter m1 { type ipv4_addr : counter \;} $nft add element ip filter m1 { 1 : c1 } $nft add element ip filter m1 { 1 : c1 } $nft delete element ip filter m1 { 1 } $nft delete counter ip filter c1 Result: Error: Could not process rule: Device or resource busy delete counter ip filter c1 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ At the second 'nft add element ip filter m1 { 1 : c1 }', the reference count of the 'c1' is increased then it tries to insert into the 'm1'. but the 'm1' already has same element so it returns -EEXIST. But it doesn't decrease the reference count of the 'c1' in the error path. Due to a leak of the reference count of the 'c1', the 'c1' can't be removed by 'nft delete counter ip filter c1'. Fixes: 8aeff920dcc9 ("netfilter: nf_tables: add stateful object reference to set elements") Signed-off-by: Taehee Yoo Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_tables_api.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index e3ddd8e95e58..dcea979423bc 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -4506,6 +4506,8 @@ err6: err5: kfree(trans); err4: + if (obj) + obj->use--; kfree(elem.priv); err3: if (nla[NFTA_SET_ELEM_DATA] != NULL)