diff options
Diffstat (limited to 'pkg/tcpip/iptables')
-rw-r--r-- | pkg/tcpip/iptables/BUILD | 1 | ||||
-rw-r--r-- | pkg/tcpip/iptables/types.go | 3 | ||||
-rw-r--r-- | pkg/tcpip/iptables/udp_matcher.go | 113 |
3 files changed, 3 insertions, 114 deletions
diff --git a/pkg/tcpip/iptables/BUILD b/pkg/tcpip/iptables/BUILD index bab26580b..d1b73cfdf 100644 --- a/pkg/tcpip/iptables/BUILD +++ b/pkg/tcpip/iptables/BUILD @@ -8,7 +8,6 @@ go_library( "iptables.go", "targets.go", "types.go", - "udp_matcher.go", ], visibility = ["//visibility:public"], deps = [ diff --git a/pkg/tcpip/iptables/types.go b/pkg/tcpip/iptables/types.go index 7f77802a0..d660aab04 100644 --- a/pkg/tcpip/iptables/types.go +++ b/pkg/tcpip/iptables/types.go @@ -171,6 +171,9 @@ type IPHeaderFilter struct { // A Matcher is the interface for matching packets. type Matcher interface { + // Name returns the name of the Matcher. + Name() string + // Match returns whether the packet matches and whether the packet // should be "hotdropped", i.e. dropped immediately. This is usually // used for suspicious packets. diff --git a/pkg/tcpip/iptables/udp_matcher.go b/pkg/tcpip/iptables/udp_matcher.go deleted file mode 100644 index 3bb076f9c..000000000 --- a/pkg/tcpip/iptables/udp_matcher.go +++ /dev/null @@ -1,113 +0,0 @@ -// Copyright 2020 The gVisor Authors. -// -// Licensed under the Apache License, Version 2.0 (the "License"); -// you may not use this file except in compliance with the License. -// You may obtain a copy of the License at -// -// http://www.apache.org/licenses/LICENSE-2.0 -// -// Unless required by applicable law or agreed to in writing, software -// distributed under the License is distributed on an "AS IS" BASIS, -// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. -// See the License for the specific language governing permissions and -// limitations under the License. - -package iptables - -import ( - "fmt" - - "gvisor.dev/gvisor/pkg/log" - "gvisor.dev/gvisor/pkg/tcpip" - "gvisor.dev/gvisor/pkg/tcpip/header" -) - -// TODO(gvisor.dev/issue/170): The following per-matcher params should be -// supported: -// - Table name -// - Match size -// - User size -// - Hooks -// - Proto -// - Family - -// UDPMatcher matches UDP packets and their headers. It implements Matcher. -type UDPMatcher struct { - Data UDPMatcherParams -} - -// UDPMatcherParams are the parameters used to create a UDPMatcher. -type UDPMatcherParams struct { - SourcePortStart uint16 - SourcePortEnd uint16 - DestinationPortStart uint16 - DestinationPortEnd uint16 - InverseFlags uint8 -} - -// NewUDPMatcher returns a new instance of UDPMatcher. -func NewUDPMatcher(filter IPHeaderFilter, data UDPMatcherParams) (Matcher, error) { - log.Infof("Adding rule with UDPMatcherParams: %+v", data) - - if data.InverseFlags != 0 { - return nil, fmt.Errorf("unsupported UDP matcher inverse flags set") - } - - if filter.Protocol != header.UDPProtocolNumber { - return nil, fmt.Errorf("UDP matching is only valid for protocol %d.", header.UDPProtocolNumber) - } - - return &UDPMatcher{Data: data}, nil -} - -// Match implements Matcher.Match. -func (um *UDPMatcher) Match(hook Hook, pkt tcpip.PacketBuffer, interfaceName string) (bool, bool) { - netHeader := header.IPv4(pkt.NetworkHeader) - - // TODO(gvisor.dev/issue/170): Proto checks should ultimately be moved - // into the iptables.Check codepath as matchers are added. - if netHeader.TransportProtocol() != header.UDPProtocolNumber { - return false, false - } - - // We dont't match fragments. - if frag := netHeader.FragmentOffset(); frag != 0 { - if frag == 1 { - log.Warningf("Dropping UDP packet: malicious fragmented packet.") - return false, true - } - return false, false - } - - // Now we need the transport header. However, this may not have been set - // yet. - // TODO(gvisor.dev/issue/170): Parsing the transport header should - // ultimately be moved into the iptables.Check codepath as matchers are - // added. - var udpHeader header.UDP - if pkt.TransportHeader != nil { - udpHeader = header.UDP(pkt.TransportHeader) - } else { - // The UDP header hasn't been parsed yet. We have to do it here. - if len(pkt.Data.First()) < header.UDPMinimumSize { - // There's no valid UDP header here, so we hotdrop the - // packet. - log.Warningf("Dropping UDP packet: size too small.") - return false, true - } - udpHeader = header.UDP(pkt.Data.First()) - } - - // Check whether the source and destination ports are within the - // matching range. - sourcePort := udpHeader.SourcePort() - destinationPort := udpHeader.DestinationPort() - if sourcePort < um.Data.SourcePortStart || um.Data.SourcePortEnd < sourcePort { - return false, false - } - if destinationPort < um.Data.DestinationPortStart || um.Data.DestinationPortEnd < destinationPort { - return false, false - } - - return true, false -} |