diff --git a/net/netfilter/nf_nat_core.c b/net/netfilter/nf_nat_core.c index 2d06a66899b26..ffcf6529afc3c 100644 --- a/net/netfilter/nf_nat_core.c +++ b/net/netfilter/nf_nat_core.c @@ -494,38 +494,6 @@ static void nf_nat_l4proto_unique_tuple(struct nf_conntrack_tuple *tuple, goto another_round; } -static bool tuple_force_port_remap(const struct nf_conntrack_tuple *tuple) -{ - u16 sp, dp; - - switch (tuple->dst.protonum) { - case IPPROTO_TCP: - sp = ntohs(tuple->src.u.tcp.port); - dp = ntohs(tuple->dst.u.tcp.port); - break; - case IPPROTO_UDP: - case IPPROTO_UDPLITE: - sp = ntohs(tuple->src.u.udp.port); - dp = ntohs(tuple->dst.u.udp.port); - break; - default: - return false; - } - - /* IANA: System port range: 1-1023, - * user port range: 1024-49151, - * private port range: 49152-65535. - * - * Linux default ephemeral port range is 32768-60999. - * - * Enforce port remapping if sport is significantly lower - * than dport to prevent NAT port shadowing, i.e. - * accidental match of 'new' inbound connection vs. - * existing outbound one. - */ - return sp < 16384 && dp >= 32768; -} - /* Manipulate the tuple into the range given. For NF_INET_POST_ROUTING, * we change the source to map into the range. For NF_INET_PRE_ROUTING * and NF_INET_LOCAL_OUT, we change the destination to map into the @@ -539,17 +507,11 @@ get_unique_tuple(struct nf_conntrack_tuple *tuple, struct nf_conn *ct, enum nf_nat_manip_type maniptype) { - bool random_port = range->flags & NF_NAT_RANGE_PROTO_RANDOM_ALL; const struct nf_conntrack_zone *zone; struct net *net = nf_ct_net(ct); zone = nf_ct_zone(ct); - if (maniptype == NF_NAT_MANIP_SRC && - !random_port && - !ct->local_origin) - random_port = tuple_force_port_remap(orig_tuple); - /* 1) If this srcip/proto/src-proto-part is currently mapped, * and that same mapping gives a unique tuple within the given * range, use that. @@ -558,7 +520,8 @@ get_unique_tuple(struct nf_conntrack_tuple *tuple, * So far, we don't do local source mappings, so multiple * manips not an issue. */ - if (maniptype == NF_NAT_MANIP_SRC && !random_port) { + if (maniptype == NF_NAT_MANIP_SRC && + !(range->flags & NF_NAT_RANGE_PROTO_RANDOM_ALL)) { /* try the original tuple first */ if (in_range(orig_tuple, range)) { if (!nf_nat_used_tuple(orig_tuple, ct)) { @@ -582,7 +545,7 @@ get_unique_tuple(struct nf_conntrack_tuple *tuple, */ /* Only bother mapping if it's not already in range and unique */ - if (!random_port) { + if (!(range->flags & NF_NAT_RANGE_PROTO_RANDOM_ALL)) { if (range->flags & NF_NAT_RANGE_PROTO_SPECIFIED) { if (!(range->flags & NF_NAT_RANGE_PROTO_OFFSET) && l4proto_in_range(tuple, maniptype, diff --git a/tools/testing/selftests/netfilter/nft_nat.sh b/tools/testing/selftests/netfilter/nft_nat.sh index 79fe627b9e817..eb8543b9a5c40 100755 --- a/tools/testing/selftests/netfilter/nft_nat.sh +++ b/tools/testing/selftests/netfilter/nft_nat.sh @@ -880,9 +880,8 @@ EOF return $ksft_skip fi - # test default behaviour. Packet from ns1 to ns0 is not redirected - # due to automatic port translation. - test_port_shadow "default" "ROUTER" + # test default behaviour. Packet from ns1 to ns0 is redirected to ns2. + test_port_shadow "default" "CLIENT" # test packet filter based mitigation: prevent forwarding of # packets claiming to come from the service port.