diff options
| author | Jorge Boncompte <jorge@dti2.net> | 2007-05-03 03:34:42 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2007-05-03 03:34:42 -0700 |
| commit | c2a1910b06fed96db77bb358c18c52a1fcf2b7fe (patch) | |
| tree | a3e8fc944ea2a0bed4a6e02b6b0fb42e21444354 /net | |
| parent | 327850070b019a96853c533c152688546201c286 (diff) | |
[NETFILTER]: nf_nat_proto_gre: do not modify/corrupt GREv0 packets through NAT
While porting some changes of the 2.6.21-rc7 pptp/proto_gre conntrack
and nat modules to a 2.4.32 kernel I noticed that the gre_key function
returns a wrong pointer to the GRE key of a version 0 packet thus
corrupting the packet payload.
The intended behaviour for GREv0 packets is to act like
nf_conntrack_proto_generic/nf_nat_proto_unknown so I have ripped the
offending functions (not used anymore) and modified the
nf_nat_proto_gre modules to not touch version 0 (non PPTP) packets.
Signed-off-by: Jorge Boncompte <jorge@dti2.net>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv4/netfilter/nf_nat_proto_gre.c | 20 |
1 files changed, 8 insertions, 12 deletions
diff --git a/net/ipv4/netfilter/nf_nat_proto_gre.c b/net/ipv4/netfilter/nf_nat_proto_gre.c index e5a34c17d92..c3908bc5a70 100644 --- a/net/ipv4/netfilter/nf_nat_proto_gre.c +++ b/net/ipv4/netfilter/nf_nat_proto_gre.c @@ -72,6 +72,11 @@ gre_unique_tuple(struct nf_conntrack_tuple *tuple, __be16 *keyptr; unsigned int min, i, range_size; + /* If there is no master conntrack we are not PPTP, + do not change tuples */ + if (!conntrack->master) + return 0; + if (maniptype == IP_NAT_MANIP_SRC) keyptr = &tuple->src.u.gre.key; else @@ -122,18 +127,9 @@ gre_manip_pkt(struct sk_buff **pskb, unsigned int iphdroff, if (maniptype != IP_NAT_MANIP_DST) return 1; switch (greh->version) { - case 0: - if (!greh->key) { - DEBUGP("can't nat GRE w/o key\n"); - break; - } - if (greh->csum) { - /* FIXME: Never tested this code... */ - nf_proto_csum_replace4(gre_csum(greh), *pskb, - *(gre_key(greh)), - tuple->dst.u.gre.key, 0); - } - *(gre_key(greh)) = tuple->dst.u.gre.key; + case GRE_VERSION_1701: + /* We do not currently NAT any GREv0 packets. + * Try to behave like "nf_nat_proto_unknown" */ break; case GRE_VERSION_PPTP: DEBUGP("call_id -> 0x%04x\n", ntohs(tuple->dst.u.gre.key)); |