Cole Dishington [off-list ref] wrote:
quoted hunk ↗ jump to hunk
diff --git a/net/netfilter/nf_nat_core.c b/net/netfilter/nf_nat_core.c
index 7de595ead06a..4a9448684504 100644
--- a/net/netfilter/nf_nat_core.c
+++ b/net/netfilter/nf_nat_core.c
@@ -195,13 +195,36 @@ static bool nf_nat_inet_in_range(const struct nf_conntrack_tuple *t,
static bool l4proto_in_range(const struct nf_conntrack_tuple *tuple,
enum nf_nat_manip_type maniptype,
const union nf_conntrack_man_proto *min,
- const union nf_conntrack_man_proto *max)
+ const union nf_conntrack_man_proto *max,
+ const union nf_conntrack_man_proto *base,
+ bool is_psid)
{
__be16 port;
+ u16 psid, psid_mask, offset_mask;
+
+ /* In this case we are in PSID mode, avoid checking all ranges by computing bitmasks */
+ if (is_psid) {
+ u16 power_j = ntohs(max->all) - ntohs(min->all) + 1;
+ u32 offset = ntohs(base->all);
+ u16 power_a;
+
+ if (offset == 0)
+ offset = 1 << 16;
+
+ power_a = (1 << 16) / offset;
Since the dividie is only needed nat setup and not for each packet I
think its ok.
quoted hunk ↗ jump to hunk
+ if (range->flags & NF_NAT_RANGE_PSID) {
+ u16 base = ntohs(range->base_proto.all);
+ u16 min = ntohs(range->min_proto.all);
+ u16 off = 0;
+
+ /* If offset=0, port range is in one contiguous block */
+ if (base)
+ off = prandom_u32() % (((1 << 16) / base) - 1);
Bases 32769 > gives 0 for the modulo value, so perhaps compute that
independently.
You could reject > 32769 in the iptables checkentry target.
Also, base of 21846 and above always give 0 result (% 1).
I don't know psid well enough to give a recommendation here.
If such inputs are nonsensical, just reject it when userspace asks for
this and add a
if (WARN_ON_ONCE(base > bogus))
return NF_DROP;
with s small coment explaining that xtables is supposed to not provide
such value.
Other than this I think its ok.
I still dislike the 'bool is_psid' in the nat core, but I can't find
a better solution.