Hi Peter,
On Fri, Dec 02, 2011 at 09:37:04AM -0800, Pete Holland wrote:
> From: Peter Holland <pholland27@xxxxxxxxx>
>
> Make the logging of dropped packets due to ct helper rejection
> conditional on LOG_INVALID.
> This is consistent with the other uses of nf_log_packet.
> Use protocol from conntrack tuple (original direction).
> Without this check, there is a possible DoS based on traffic induced
> log generation.
> (specifically this was noted in the wild by an attacker against the SIP helper)
>
> Signed-off-by: Peter Holland <pholland27@xxxxxxxxx>
> ---
> --- net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c.orig 2011-11-29
> 11:34:36.683717278 -0800
> +++ net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c 2011-12-02
> 09:32:00.727064563 -0800
> @@ -116,8 +116,10 @@ static unsigned int ipv4_confirm(unsigne
> ret = helper->help(skb, skb_network_offset(skb) + ip_hdrlen(skb),
> ct, ctinfo);
> if (ret != NF_ACCEPT) {
> - nf_log_packet(NFPROTO_IPV4, hooknum, skb, in, out, NULL,
> - "nf_ct_%s: dropping packet", helper->name);
> + if (LOG_INVALID(nf_ct_net(ct),
> + ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum))
You can use nf_ct_protonum here.
> + nf_log_packet(NFPROTO_IPV4, hooknum, skb, in, out, NULL,
> + "nf_ct_%s: dropping packet", helper->name);
> return ret;
> }
Below you can find:
/* adjust seqs for loopback traffic only in outgoing direction */
if (test_bit(IPS_SEQ_ADJUST_BIT, &ct->status) &&
!nf_is_loopback_packet(skb)) {
typeof(nf_nat_seq_adjust_hook) seq_adjust;
seq_adjust = rcu_dereference(nf_nat_seq_adjust_hook);
if (!seq_adjust || !seq_adjust(skb, ct, ctinfo)) {
NF_CT_STAT_INC_ATOMIC(nf_ct_net(ct), drop);
^^^^^^^^^^^^
Please, declare in ipv4_confirm:
struct net *net = nf_ct_net(ct);
And use the net pointer in that function.
Same thing for the IPv6 side.
Thank you.
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