diff options
| author | Florian Westphal <fw@strlen.de> | 2019-04-09 14:45:20 +0200 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2019-04-15 07:31:50 +0200 |
| commit | 5bdac418f33f60b07a34e01e722889140ee8fac9 (patch) | |
| tree | 8dd81d36f4c9ba89f4ad8779f8055e24f8069118 /net | |
| parent | 33d1c018179d0a30c39cc5f1682b77867282694b (diff) | |
netfilter: nat: fix icmp id randomization
Sven Auhagen reported that a 2nd ping request will fail if 'fully-random'
mode is used.
Reason is that if no proto information is given, min/max are both 0,
so we set the icmp id to 0 instead of chosing a random value between
0 and 65535.
Update test case as well to catch this, without fix this yields:
[..]
ERROR: cannot ping ns1 from ns2 with ip masquerade fully-random (attempt 2)
ERROR: cannot ping ns1 from ns2 with ipv6 masquerade fully-random (attempt 2)
... becaus 2nd ping clashes with existing 'id 0' icmp conntrack and gets
dropped.
Fixes: 203f2e78200c27e ("netfilter: nat: remove l4proto->unique_tuple")
Reported-by: Sven Auhagen <sven.auhagen@voleatech.de>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/netfilter/nf_nat_core.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/net/netfilter/nf_nat_core.c b/net/netfilter/nf_nat_core.c index af7dc6537758..000952719adf 100644 --- a/net/netfilter/nf_nat_core.c +++ b/net/netfilter/nf_nat_core.c @@ -415,9 +415,14 @@ static void nf_nat_l4proto_unique_tuple(struct nf_conntrack_tuple *tuple, case IPPROTO_ICMPV6: /* id is same for either direction... */ keyptr = &tuple->src.u.icmp.id; - min = range->min_proto.icmp.id; - range_size = ntohs(range->max_proto.icmp.id) - - ntohs(range->min_proto.icmp.id) + 1; + if (!(range->flags & NF_NAT_RANGE_PROTO_SPECIFIED)) { + min = 0; + range_size = 65536; + } else { + min = ntohs(range->min_proto.icmp.id); + range_size = ntohs(range->max_proto.icmp.id) - + ntohs(range->min_proto.icmp.id) + 1; + } goto find_free_id; #if IS_ENABLED(CONFIG_NF_CT_PROTO_GRE) case IPPROTO_GRE: |