From: Liping Zhang <zlpnob...@gmail.com>
When dumping nft stateful objects, if NFTA_OBJ_TABLE and NFTA_OBJ_TYPE
attributes are not specified either, filter will become NULL, so oops
will happen(actually nft utility will always set NFTA_OBJ_TABLE attr,
so I write a test program to make this happen):
BUG: unable to handle kernel NULL pointer dereference at (null)
IP: nf_tables_dump_obj+0x17c/0x330 [nf_tables]
[...]
Call Trace:
? nf_tables_dump_obj+0x5/0x330 [nf_tables]
? __kmalloc_reserve.isra.35+0x31/0x90
? __alloc_skb+0x5b/0x1e0
netlink_dump+0x124/0x2a0
__netlink_dump_start+0x161/0x190
nf_tables_getobj+0xe8/0x280 [nf_tables]
Fixes: a9fea2a3c3cf ("netfilter: nf_tables: allow to filter stateful object
dumps by type")
Signed-off-by: Liping Zhang <zlpnob...@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pa...@netfilter.org>
---
net/netfilter/nf_tables_api.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 0db5f9782265..091d2dcc63b2 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -4262,10 +4262,11 @@ static int nf_tables_dump_obj(struct sk_buff *skb,
struct netlink_callback *cb)
if (idx > s_idx)
memset(&cb->args[1], 0,
sizeof(cb->args) -
sizeof(cb->args[0]));
- if (filter->table[0] &&
+ if (filter && filter->table[0] &&
strcmp(filter->table, table->name))
goto cont;
- if (filter->type != NFT_OBJECT_UNSPEC &&
+ if (filter &&
+ filter->type != NFT_OBJECT_UNSPEC &&
obj->type->type != filter->type)
goto cont;
--
2.1.4
