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netfilter: nft_reject: restrict to INPUT/FORWARD/OUTPUT

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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 <liping.zhang@spreadtrum.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Liping Zhang
2016-08-22 01:02:18 +08:00
committed by Pablo Neira Ayuso
parent 51af96b534
commit 89e1f6d2b9
5 changed files with 28 additions and 1 deletions
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1
net/ipv6/netfilter/nft_reject_ipv6.c
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@@ -47,6 +47,7 @@ static const struct nft_expr_ops nft_reject_ipv6_ops = {
.eval = nft_reject_ipv6_eval,
.init = nft_reject_init,
.dump = nft_reject_dump,
.validate = nft_reject_validate,
};
static struct nft_expr_type nft_reject_ipv6_type __read_mostly = {