netdev - [PATCH 3/3] netfilter: nf_tables: fix potential NULL-ptr deref in nf_tables_dump_obj

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Date:   Fri,  5 Jan 2018 16:08:25 +0100
From:   Pablo Neira Ayuso <pablo@...filter.org>
To:     netfilter-devel@...r.kernel.org
Cc:     davem@...emloft.net, netdev@...r.kernel.org
Subject: [PATCH 3/3] netfilter: nf_tables: fix potential NULL-ptr deref in nf_tables_dump_obj_done()

From: Hangbin Liu <liuhangbin@...il.com>

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@...il.com>
Acked-by: Phil Sutter <phil@....cc>
Signed-off-by: Pablo Neira Ayuso <pablo@...filter.org>
---
 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 8d4526651661..07bd4138c84e 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -4665,8 +4665,10 @@ 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