diff options
author | Jesper Dangaard Brouer <brouer@redhat.com> | 2012-09-26 14:06:41 +0200 |
---|---|---|
committer | Simon Horman <horms@verge.net.au> | 2012-09-28 11:34:15 +0900 |
commit | 63dca2c0b0e7a92cb39d1b1ecefa32ffda201975 (patch) | |
tree | 4998cbf50a15ab5a939dc8cd722c668f601ba3cc /net/netfilter/ipvs/ip_vs_xmit.c | |
parent | a638e51437f5efd00c4579df56cfd4d497ed51a8 (diff) |
ipvs: Fix faulty IPv6 extension header handling in IPVS
IPv6 packets can contain extension headers, thus its wrong to assume
that the transport/upper-layer header, starts right after (struct
ipv6hdr) the IPv6 header. IPVS uses this false assumption, and will
write SNAT & DNAT modifications at a fixed pos which will corrupt the
message.
To fix this, proper header position must be found before modifying
packets. Introducing ip_vs_fill_iph_skb(), which uses ipv6_find_hdr()
to skip the exthdrs. It finds (1) the transport header offset, (2) the
protocol, and (3) detects if the packet is a fragment.
Note, that fragments in IPv6 is represented via an exthdr. Thus, this
is detected while skipping through the exthdrs.
This patch depends on commit 84018f55a:
"netfilter: ip6_tables: add flags parameter to ipv6_find_hdr()"
This also adds a dependency to ip6_tables.
Originally based on patch from: Hans Schillstrom
kABI notes:
Changing struct ip_vs_iphdr is a potential minor kABI breaker,
because external modules can be compiled with another version of
this struct. This should not matter, as they would most-likely
be using a compiled-in version of ip_vs_fill_iphdr(). When
recompiled, they will notice ip_vs_fill_iphdr() no longer exists,
and they have to used ip_vs_fill_iph_skb() instead.
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>
Diffstat (limited to 'net/netfilter/ipvs/ip_vs_xmit.c')
-rw-r--r-- | net/netfilter/ipvs/ip_vs_xmit.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/net/netfilter/ipvs/ip_vs_xmit.c b/net/netfilter/ipvs/ip_vs_xmit.c index 1060bd52a165..428de7579577 100644 --- a/net/netfilter/ipvs/ip_vs_xmit.c +++ b/net/netfilter/ipvs/ip_vs_xmit.c @@ -679,14 +679,15 @@ ip_vs_nat_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp, struct rt6_info *rt; /* Route to the other host */ int mtu; int local; + struct ip_vs_iphdr iph; EnterFunction(10); + ip_vs_fill_iph_skb(cp->af, skb, &iph); /* check if it is a connection of no-client-port */ if (unlikely(cp->flags & IP_VS_CONN_F_NO_CPORT)) { __be16 _pt, *p; - p = skb_header_pointer(skb, sizeof(struct ipv6hdr), - sizeof(_pt), &_pt); + p = skb_header_pointer(skb, iph.len, sizeof(_pt), &_pt); if (p == NULL) goto tx_error; ip_vs_conn_fill_cport(cp, *p); |