diff options
| author |   Florian Westphal <fw@strlen.de> | 2015-02-16 18:54:04 +0100 |
|---|---|---|
| committer |   Pablo Neira Ayuso <pablo@netfilter.org> | 2015-03-03 02:10:35 +0100 |
| commit | ee586bbc28fb7128133457cf711880d13a3b7ce4 (patch) | |
| tree | d1e1991b5d622b588c11608b9164499a96869e51 /net/ipv4/netfilter/ipt_REJECT.c | |
| parent | Merge branch 'neigh_cleanups' (diff) | |
| download | linux-dev-ee586bbc28fb7128133457cf711880d13a3b7ce4.tar.xz linux-dev-ee586bbc28fb7128133457cf711880d13a3b7ce4.zip | |
netfilter: reject: don't send icmp error if csum is invalid
tcp resets are never emitted if the packet that triggers the
reject/reset has an invalid checksum.
For icmp error responses there was no such check.
It allows to distinguish icmp response generated via
iptables -I INPUT -p udp --dport 42 -j REJECT
and those emitted by network stack (won't respond if csum is invalid,
REJECT does).
Arguably its possible to avoid this by using conntrack and only
using REJECT with -m conntrack NEW/RELATED.
However, this doesn't work when connection tracking is not in use
or when using nf_conntrack_checksum=0.
Furthermore, sending errors in response to invalid csums doesn't make
much sense so just add similar test as in nf_send_reset.
Validate csum if needed and only send the response if it is ok.
Reference: http://bugzilla.redhat.com/show_bug.cgi?id=1169829
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to '')
| -rw-r--r-- | net/ipv4/netfilter/ipt_REJECT.c | 17 |
1 files changed, 9 insertions, 8 deletions
diff --git a/net/ipv4/netfilter/ipt_REJECT.c b/net/ipv4/netfilter/ipt_REJECT.c index 8f48f5517e33..87907d4bd259 100644 --- a/net/ipv4/netfilter/ipt_REJECT.c +++ b/net/ipv4/netfilter/ipt_REJECT.c @@ -34,31 +34,32 @@ static unsigned int reject_tg(struct sk_buff *skb, const struct xt_action_param *par) { const struct ipt_reject_info *reject = par->targinfo; + int hook = par->hooknum; switch (reject->with) { case IPT_ICMP_NET_UNREACHABLE: - nf_send_unreach(skb, ICMP_NET_UNREACH); + nf_send_unreach(skb, ICMP_NET_UNREACH, hook); break; case IPT_ICMP_HOST_UNREACHABLE: - nf_send_unreach(skb, ICMP_HOST_UNREACH); + nf_send_unreach(skb, ICMP_HOST_UNREACH, hook); break; case IPT_ICMP_PROT_UNREACHABLE: - nf_send_unreach(skb, ICMP_PROT_UNREACH); + nf_send_unreach(skb, ICMP_PROT_UNREACH, hook); break; case IPT_ICMP_PORT_UNREACHABLE: - nf_send_unreach(skb, ICMP_PORT_UNREACH); + nf_send_unreach(skb, ICMP_PORT_UNREACH, hook); break; case IPT_ICMP_NET_PROHIBITED: - nf_send_unreach(skb, ICMP_NET_ANO); + nf_send_unreach(skb, ICMP_NET_ANO, hook); break; case IPT_ICMP_HOST_PROHIBITED: - nf_send_unreach(skb, ICMP_HOST_ANO); + nf_send_unreach(skb, ICMP_HOST_ANO, hook); break; case IPT_ICMP_ADMIN_PROHIBITED: - nf_send_unreach(skb, ICMP_PKT_FILTERED); + nf_send_unreach(skb, ICMP_PKT_FILTERED, hook); break; case IPT_TCP_RESET: - nf_send_reset(skb, par->hooknum); + nf_send_reset(skb, hook); case IPT_ICMP_ECHOREPLY: /* Doesn't happen. */ break; |