[PATCH AUTOSEL for 4.14 058/110] netfilter: nf_tables: fix potential NULL-ptr deref in nf_tables_dump_obj_done()

From: Sasha Levin
Date: Sat Feb 03 2018 - 13:35:02 EST


From: Hangbin Liu <liuhangbin@xxxxxxxxx>

[ Upstream commit 8bea728dce8972e534e6b99fd550f7b5cc3864e8 ]

If there is no NFTA_OBJ_TABLE and NFTA_OBJ_TYPE, the c.data will be NULL in
nf_tables_getobj(). So before free filter->table in nf_tables_dump_obj_done(),
we need to check if filter is NULL first.

Fixes: e46abbcc05aa ("netfilter: nf_tables: Allow table names of up to 255 chars")
Signed-off-by: Hangbin Liu <liuhangbin@xxxxxxxxx>
Acked-by: Phil Sutter <phil@xxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
---
net/netfilter/nf_tables_api.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index ce49946f755e..5b504aa653f5 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -4596,8 +4596,10 @@ static int nf_tables_dump_obj_done(struct netlink_callback *cb)
{
struct nft_obj_filter *filter = cb->data;

- kfree(filter->table);
- kfree(filter);
+ if (filter) {
+ kfree(filter->table);
+ kfree(filter);
+ }

return 0;
}
--
2.11.0