[PATCH 4.14 055/115] netfilter: nf_tables: fix potential NULL-ptr deref in nf_tables_dump_obj_done()

From: Greg Kroah-Hartman
Date: Fri Mar 02 2018 - 04:02:06 EST


4.14-stable review patch. If anyone has any objections, please let me know.

------------------

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@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/netfilter/nf_tables_api.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

--- 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(struc
{
struct nft_obj_filter *filter = cb->data;

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

return 0;
}