netfilter: nft_reject: restrict to INPUT/FORWARD/OUTPUT

After I add the nft rule "nft add rule filter prerouting reject
with tcp reset", kernel panic happened on my system:
  NULL pointer dereference at ...
  IP: [<ffffffff81b9db2f>] nf_send_reset+0xaf/0x400
  Call Trace:
  [<ffffffff81b9da80>] ? nf_reject_ip_tcphdr_get+0x160/0x160
  [<ffffffffa0928061>] nft_reject_ipv4_eval+0x61/0xb0 [nft_reject_ipv4]
  [<ffffffffa08e836a>] nft_do_chain+0x1fa/0x890 [nf_tables]
  [<ffffffffa08e8170>] ? __nft_trace_packet+0x170/0x170 [nf_tables]
  [<ffffffffa06e0900>] ? nf_ct_invert_tuple+0xb0/0xc0 [nf_conntrack]
  [<ffffffffa07224d4>] ? nf_nat_setup_info+0x5d4/0x650 [nf_nat]
  [...]

Because in the PREROUTING chain, routing information is not exist,
then we will dereference the NULL pointer and oops happen.

So we restrict reject expression to INPUT, FORWARD and OUTPUT chain.
This is consistent with iptables REJECT target.

Signed-off-by: Liping Zhang <[email protected]>
Signed-off-by: Pablo Neira Ayuso <[email protected]>
This commit is contained in:
Liping Zhang 2016-08-22 01:02:18 +08:00 • committed by Pablo Neira Ayuso
commit 89e1f6d2b9
5 changed files with 28 additions and 1 deletions

View file

@ -46,6 +46,7 @@ static const struct nft_expr_ops nft_reject_ipv4_ops = {
.eval = nft_reject_ipv4_eval,
.init = nft_reject_init,
.dump = nft_reject_dump,
.validate = nft_reject_validate,
};
static struct nft_expr_type nft_reject_ipv4_type __read_mostly = {