diff --git a/pkg/tcpip/stack/transport_demuxer.go b/pkg/tcpip/stack/transport_demuxer.go index cb805522b..67c21be42 100644 --- a/pkg/tcpip/stack/transport_demuxer.go +++ b/pkg/tcpip/stack/transport_demuxer.go @@ -389,8 +389,8 @@ var loopbackSubnet = func() tcpip.Subnet { }() // deliverPacket attempts to find one or more matching transport endpoints, and -// then, if matches are found, delivers the packet to them. Returns true if it -// found one or more endpoints, false otherwise. +// then, if matches are found, delivers the packet to them. Returns true if +// the packet no longer needs to be handled. func (d *transportDemuxer) deliverPacket(r *Route, protocol tcpip.TransportProtocolNumber, pkt tcpip.PacketBuffer, id TransportEndpointID) bool { eps, ok := d.protocol[protocolIDs{r.NetProto, protocol}] if !ok { @@ -400,13 +400,38 @@ func (d *transportDemuxer) deliverPacket(r *Route, protocol tcpip.TransportProto eps.mu.RLock() // Determine which transport endpoint or endpoints to deliver this packet to. - // If the packet is a broadcast or multicast, then find all matching - // transport endpoints. + // If the packet is a UDP broadcast or multicast, then find all matching + // transport endpoints. If the packet is a TCP packet with a non-unicast + // source or destination address, then do nothing further and instruct + // the caller to do the same. var destEps []*endpointsByNic - if protocol == header.UDPProtocolNumber && isMulticastOrBroadcast(id.LocalAddress) { - destEps = d.findAllEndpointsLocked(eps, id) - } else if ep := d.findEndpointLocked(eps, id); ep != nil { - destEps = append(destEps, ep) + switch protocol { + case header.UDPProtocolNumber: + if isMulticastOrBroadcast(id.LocalAddress) { + destEps = d.findAllEndpointsLocked(eps, id) + break + } + + if ep := d.findEndpointLocked(eps, id); ep != nil { + destEps = append(destEps, ep) + } + + case header.TCPProtocolNumber: + if !(isUnicast(r.LocalAddress) && isUnicast(r.RemoteAddress)) { + // TCP can only be used to communicate between a single + // source and a single destination; the addresses must + // be unicast. + eps.mu.RUnlock() + r.Stats().TCP.InvalidSegmentsReceived.Increment() + return true + } + + fallthrough + + default: + if ep := d.findEndpointLocked(eps, id); ep != nil { + destEps = append(destEps, ep) + } } eps.mu.RUnlock() @@ -587,3 +612,7 @@ func (d *transportDemuxer) unregisterRawEndpoint(netProto tcpip.NetworkProtocolN func isMulticastOrBroadcast(addr tcpip.Address) bool { return addr == header.IPv4Broadcast || header.IsV4MulticastAddress(addr) || header.IsV6MulticastAddress(addr) } + +func isUnicast(addr tcpip.Address) bool { + return addr != header.IPv4Any && addr != header.IPv6Any && !isMulticastOrBroadcast(addr) +} diff --git a/pkg/tcpip/transport/tcp/tcp_test.go b/pkg/tcpip/transport/tcp/tcp_test.go index 84579ce52..b443fe9dc 100644 --- a/pkg/tcpip/transport/tcp/tcp_test.go +++ b/pkg/tcpip/transport/tcp/tcp_test.go @@ -4242,6 +4242,210 @@ func TestListenBacklogFull(t *testing.T) { } } +// TestListenNoAcceptMulticastBroadcastV4 makes sure that TCP segments with a +// non unicast IPv4 address are not accepted. +func TestListenNoAcceptNonUnicastV4(t *testing.T) { + multicastAddr := tcpip.Address("\xe0\x00\x01\x02") + otherMulticastAddr := tcpip.Address("\xe0\x00\x01\x03") + + tests := []struct { + name string + srcAddr tcpip.Address + dstAddr tcpip.Address + }{ + { + "SourceUnspecified", + header.IPv4Any, + context.StackAddr, + }, + { + "SourceBroadcast", + header.IPv4Broadcast, + context.StackAddr, + }, + { + "SourceOurMulticast", + multicastAddr, + context.StackAddr, + }, + { + "SourceOtherMulticast", + otherMulticastAddr, + context.StackAddr, + }, + { + "DestUnspecified", + context.TestAddr, + header.IPv4Any, + }, + { + "DestBroadcast", + context.TestAddr, + header.IPv4Broadcast, + }, + { + "DestOurMulticast", + context.TestAddr, + multicastAddr, + }, + { + "DestOtherMulticast", + context.TestAddr, + otherMulticastAddr, + }, + } + + for _, test := range tests { + t.Run(test.name, func(t *testing.T) { + t.Parallel() + + c := context.New(t, defaultMTU) + defer c.Cleanup() + + c.Create(-1) + + if err := c.Stack().JoinGroup(header.IPv4ProtocolNumber, 1, multicastAddr); err != nil { + t.Fatalf("JoinGroup failed: %s", err) + } + + if err := c.EP.Bind(tcpip.FullAddress{Port: context.StackPort}); err != nil { + t.Fatalf("Bind failed: %s", err) + } + + if err := c.EP.Listen(1); err != nil { + t.Fatalf("Listen failed: %s", err) + } + + irs := seqnum.Value(789) + c.SendPacketWithAddrs(nil, &context.Headers{ + SrcPort: context.TestPort, + DstPort: context.StackPort, + Flags: header.TCPFlagSyn, + SeqNum: irs, + RcvWnd: 30000, + }, test.srcAddr, test.dstAddr) + c.CheckNoPacket("Should not have received a response") + + // Handle normal packet. + c.SendPacketWithAddrs(nil, &context.Headers{ + SrcPort: context.TestPort, + DstPort: context.StackPort, + Flags: header.TCPFlagSyn, + SeqNum: irs, + RcvWnd: 30000, + }, context.TestAddr, context.StackAddr) + checker.IPv4(t, c.GetPacket(), + checker.TCP( + checker.SrcPort(context.StackPort), + checker.DstPort(context.TestPort), + checker.TCPFlags(header.TCPFlagAck|header.TCPFlagSyn), + checker.AckNum(uint32(irs)+1))) + }) + } +} + +// TestListenNoAcceptMulticastBroadcastV6 makes sure that TCP segments with a +// non unicast IPv6 address are not accepted. +func TestListenNoAcceptNonUnicastV6(t *testing.T) { + multicastAddr := tcpip.Address("\xff\x0e\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\x01") + otherMulticastAddr := tcpip.Address("\xff\x0e\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\x02") + + tests := []struct { + name string + srcAddr tcpip.Address + dstAddr tcpip.Address + }{ + { + "SourceUnspecified", + header.IPv6Any, + context.StackV6Addr, + }, + { + "SourceAllNodes", + header.IPv6AllNodesMulticastAddress, + context.StackV6Addr, + }, + { + "SourceOurMulticast", + multicastAddr, + context.StackV6Addr, + }, + { + "SourceOtherMulticast", + otherMulticastAddr, + context.StackV6Addr, + }, + { + "DestUnspecified", + context.TestV6Addr, + header.IPv6Any, + }, + { + "DestAllNodes", + context.TestV6Addr, + header.IPv6AllNodesMulticastAddress, + }, + { + "DestOurMulticast", + context.TestV6Addr, + multicastAddr, + }, + { + "DestOtherMulticast", + context.TestV6Addr, + otherMulticastAddr, + }, + } + + for _, test := range tests { + t.Run(test.name, func(t *testing.T) { + t.Parallel() + + c := context.New(t, defaultMTU) + defer c.Cleanup() + + c.CreateV6Endpoint(true) + + if err := c.Stack().JoinGroup(header.IPv6ProtocolNumber, 1, multicastAddr); err != nil { + t.Fatalf("JoinGroup failed: %s", err) + } + + if err := c.EP.Bind(tcpip.FullAddress{Port: context.StackPort}); err != nil { + t.Fatalf("Bind failed: %s", err) + } + + if err := c.EP.Listen(1); err != nil { + t.Fatalf("Listen failed: %s", err) + } + + irs := seqnum.Value(789) + c.SendV6PacketWithAddrs(nil, &context.Headers{ + SrcPort: context.TestPort, + DstPort: context.StackPort, + Flags: header.TCPFlagSyn, + SeqNum: irs, + RcvWnd: 30000, + }, test.srcAddr, test.dstAddr) + c.CheckNoPacket("Should not have received a response") + + // Handle normal packet. + c.SendV6PacketWithAddrs(nil, &context.Headers{ + SrcPort: context.TestPort, + DstPort: context.StackPort, + Flags: header.TCPFlagSyn, + SeqNum: irs, + RcvWnd: 30000, + }, context.TestV6Addr, context.StackV6Addr) + checker.IPv6(t, c.GetV6Packet(), + checker.TCP( + checker.SrcPort(context.StackPort), + checker.DstPort(context.TestPort), + checker.TCPFlags(header.TCPFlagAck|header.TCPFlagSyn), + checker.AckNum(uint32(irs)+1))) + }) + } +} + func TestListenSynRcvdQueueFull(t *testing.T) { c := context.New(t, defaultMTU) defer c.Cleanup() diff --git a/pkg/tcpip/transport/tcp/testing/context/context.go b/pkg/tcpip/transport/tcp/testing/context/context.go index 4854e719d..0a733fa94 100644 --- a/pkg/tcpip/transport/tcp/testing/context/context.go +++ b/pkg/tcpip/transport/tcp/testing/context/context.go @@ -309,6 +309,12 @@ func (c *Context) SendICMPPacket(typ header.ICMPv4Type, code uint8, p1, p2 []byt // BuildSegment builds a TCP segment based on the given Headers and payload. func (c *Context) BuildSegment(payload []byte, h *Headers) buffer.VectorisedView { + return c.BuildSegmentWithAddrs(payload, h, TestAddr, StackAddr) +} + +// BuildSegmentWithAddrs builds a TCP segment based on the given Headers, +// payload and source and destination IPv4 addresses. +func (c *Context) BuildSegmentWithAddrs(payload []byte, h *Headers, src, dst tcpip.Address) buffer.VectorisedView { // Allocate a buffer for data and headers. buf := buffer.NewView(header.TCPMinimumSize + header.IPv4MinimumSize + len(h.TCPOpts) + len(payload)) copy(buf[len(buf)-len(payload):], payload) @@ -321,8 +327,8 @@ func (c *Context) BuildSegment(payload []byte, h *Headers) buffer.VectorisedView TotalLength: uint16(len(buf)), TTL: 65, Protocol: uint8(tcp.ProtocolNumber), - SrcAddr: TestAddr, - DstAddr: StackAddr, + SrcAddr: src, + DstAddr: dst, }) ip.SetChecksum(^ip.CalculateChecksum()) @@ -339,7 +345,7 @@ func (c *Context) BuildSegment(payload []byte, h *Headers) buffer.VectorisedView }) // Calculate the TCP pseudo-header checksum. - xsum := header.PseudoHeaderChecksum(tcp.ProtocolNumber, TestAddr, StackAddr, uint16(len(t))) + xsum := header.PseudoHeaderChecksum(tcp.ProtocolNumber, src, dst, uint16(len(t))) // Calculate the TCP checksum and set it. xsum = header.Checksum(payload, xsum) @@ -365,6 +371,15 @@ func (c *Context) SendPacket(payload []byte, h *Headers) { }) } +// SendPacketWithAddrs builds and sends a TCP segment(with the provided payload +// & TCPheaders) in an IPv4 packet via the link layer endpoint using the +// provided source and destination IPv4 addresses. +func (c *Context) SendPacketWithAddrs(payload []byte, h *Headers, src, dst tcpip.Address) { + c.linkEP.InjectInbound(ipv4.ProtocolNumber, tcpip.PacketBuffer{ + Data: c.BuildSegmentWithAddrs(payload, h, src, dst), + }) +} + // SendAck sends an ACK packet. func (c *Context) SendAck(seq seqnum.Value, bytesReceived int) { c.SendAckWithSACK(seq, bytesReceived, nil) @@ -490,6 +505,13 @@ func (c *Context) GetV6Packet() []byte { // SendV6Packet builds and sends an IPv6 Packet via the link layer endpoint of // the context. func (c *Context) SendV6Packet(payload []byte, h *Headers) { + c.SendV6PacketWithAddrs(payload, h, TestV6Addr, StackV6Addr) +} + +// SendV6PacketWithAddrs builds and sends an IPv6 Packet via the link layer +// endpoint of the context using the provided source and destination IPv6 +// addresses. +func (c *Context) SendV6PacketWithAddrs(payload []byte, h *Headers, src, dst tcpip.Address) { // Allocate a buffer for data and headers. buf := buffer.NewView(header.TCPMinimumSize + header.IPv6MinimumSize + len(payload)) copy(buf[len(buf)-len(payload):], payload) @@ -500,8 +522,8 @@ func (c *Context) SendV6Packet(payload []byte, h *Headers) { PayloadLength: uint16(header.TCPMinimumSize + len(payload)), NextHeader: uint8(tcp.ProtocolNumber), HopLimit: 65, - SrcAddr: TestV6Addr, - DstAddr: StackV6Addr, + SrcAddr: src, + DstAddr: dst, }) // Initialize the TCP header. @@ -517,7 +539,7 @@ func (c *Context) SendV6Packet(payload []byte, h *Headers) { }) // Calculate the TCP pseudo-header checksum. - xsum := header.PseudoHeaderChecksum(tcp.ProtocolNumber, TestV6Addr, StackV6Addr, uint16(len(t))) + xsum := header.PseudoHeaderChecksum(tcp.ProtocolNumber, src, dst, uint16(len(t))) // Calculate the TCP checksum and set it. xsum = header.Checksum(payload, xsum)