diff options
28 files changed, 539 insertions, 364 deletions
diff --git a/pkg/sentry/socket/netfilter/tcp_matcher.go b/pkg/sentry/socket/netfilter/tcp_matcher.go index ebabdf334..4f98ee2d5 100644 --- a/pkg/sentry/socket/netfilter/tcp_matcher.go +++ b/pkg/sentry/socket/netfilter/tcp_matcher.go @@ -111,36 +111,10 @@ func (tm *TCPMatcher) Match(hook stack.Hook, pkt *stack.PacketBuffer, interfaceN 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 stack.Check codepath as matchers are - // added. - var tcpHeader header.TCP - if pkt.TransportHeader != nil { - tcpHeader = header.TCP(pkt.TransportHeader) - } else { - var length int - if hook == stack.Prerouting { - // The network header hasn't been parsed yet. We have to do it here. - hdr, ok := pkt.Data.PullUp(header.IPv4MinimumSize) - if !ok { - // There's no valid TCP header here, so we hotdrop the - // packet. - return false, true - } - h := header.IPv4(hdr) - pkt.NetworkHeader = hdr - length = int(h.HeaderLength()) - } - // The TCP header hasn't been parsed yet. We have to do it here. - hdr, ok := pkt.Data.PullUp(length + header.TCPMinimumSize) - if !ok { - // There's no valid TCP header here, so we hotdrop the - // packet. - return false, true - } - tcpHeader = header.TCP(hdr[length:]) + tcpHeader := header.TCP(pkt.TransportHeader) + if len(tcpHeader) < header.TCPMinimumSize { + // There's no valid TCP header here, so we drop the packet immediately. + return false, true } // Check whether the source and destination ports are within the diff --git a/pkg/sentry/socket/netfilter/udp_matcher.go b/pkg/sentry/socket/netfilter/udp_matcher.go index 98b9943f8..3f20fc891 100644 --- a/pkg/sentry/socket/netfilter/udp_matcher.go +++ b/pkg/sentry/socket/netfilter/udp_matcher.go @@ -110,36 +110,10 @@ func (um *UDPMatcher) Match(hook stack.Hook, pkt *stack.PacketBuffer, interfaceN 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 stack.Check codepath as matchers are - // added. - var udpHeader header.UDP - if pkt.TransportHeader != nil { - udpHeader = header.UDP(pkt.TransportHeader) - } else { - var length int - if hook == stack.Prerouting { - // The network header hasn't been parsed yet. We have to do it here. - hdr, ok := pkt.Data.PullUp(header.IPv4MinimumSize) - if !ok { - // There's no valid UDP header here, so we hotdrop the - // packet. - return false, true - } - h := header.IPv4(hdr) - pkt.NetworkHeader = hdr - length = int(h.HeaderLength()) - } - // The UDP header hasn't been parsed yet. We have to do it here. - hdr, ok := pkt.Data.PullUp(length + header.UDPMinimumSize) - if !ok { - // There's no valid UDP header here, so we hotdrop the - // packet. - return false, true - } - udpHeader = header.UDP(hdr[length:]) + udpHeader := header.UDP(pkt.TransportHeader) + if len(udpHeader) < header.UDPMinimumSize { + // There's no valid UDP header here, so we drop the packet immediately. + return false, true } // Check whether the source and destination ports are within the diff --git a/pkg/tcpip/header/ipv4.go b/pkg/tcpip/header/ipv4.go index 76839eb92..62ac932bb 100644 --- a/pkg/tcpip/header/ipv4.go +++ b/pkg/tcpip/header/ipv4.go @@ -159,6 +159,11 @@ func (b IPv4) Flags() uint8 { return uint8(binary.BigEndian.Uint16(b[flagsFO:]) >> 13) } +// More returns whether the more fragments flag is set. +func (b IPv4) More() bool { + return b.Flags()&IPv4FlagMoreFragments != 0 +} + // TTL returns the "TTL" field of the ipv4 header. func (b IPv4) TTL() uint8 { return b[ttl] diff --git a/pkg/tcpip/header/ipv6_extension_headers.go b/pkg/tcpip/header/ipv6_extension_headers.go index 2c4591409..3499d8399 100644 --- a/pkg/tcpip/header/ipv6_extension_headers.go +++ b/pkg/tcpip/header/ipv6_extension_headers.go @@ -354,6 +354,13 @@ func (b IPv6FragmentExtHdr) ID() uint32 { return binary.BigEndian.Uint32(b[ipv6FragmentExtHdrIdentificationOffset:]) } +// IsAtomic returns whether the fragment header indicates an atomic fragment. An +// atomic fragment is a fragment that contains all the data required to +// reassemble a full packet. +func (b IPv6FragmentExtHdr) IsAtomic() bool { + return !b.More() && b.FragmentOffset() == 0 +} + // IPv6PayloadIterator is an iterator over the contents of an IPv6 payload. // // The IPv6 payload may contain IPv6 extension headers before any upper layer diff --git a/pkg/tcpip/network/arp/arp.go b/pkg/tcpip/network/arp/arp.go index ea1acba83..7f27a840d 100644 --- a/pkg/tcpip/network/arp/arp.go +++ b/pkg/tcpip/network/arp/arp.go @@ -99,11 +99,7 @@ func (e *endpoint) WriteHeaderIncludedPacket(r *stack.Route, pkt *stack.PacketBu } func (e *endpoint) HandlePacket(r *stack.Route, pkt *stack.PacketBuffer) { - v, ok := pkt.Data.PullUp(header.ARPSize) - if !ok { - return - } - h := header.ARP(v) + h := header.ARP(pkt.NetworkHeader) if !h.IsValid() { return } @@ -209,6 +205,17 @@ func (*protocol) Close() {} // Wait implements stack.TransportProtocol.Wait. func (*protocol) Wait() {} +// Parse implements stack.NetworkProtocol.Parse. +func (*protocol) Parse(pkt *stack.PacketBuffer) (proto tcpip.TransportProtocolNumber, hasTransportHdr bool, ok bool) { + hdr, ok := pkt.Data.PullUp(header.ARPSize) + if !ok { + return 0, false, false + } + pkt.NetworkHeader = hdr + pkt.Data.TrimFront(header.ARPSize) + return 0, false, true +} + var broadcastMAC = tcpip.LinkAddress([]byte{0xff, 0xff, 0xff, 0xff, 0xff, 0xff}) // NewProtocol returns an ARP network protocol. diff --git a/pkg/tcpip/network/fragmentation/fragmentation.go b/pkg/tcpip/network/fragmentation/fragmentation.go index f42abc4bb..2982450f8 100644 --- a/pkg/tcpip/network/fragmentation/fragmentation.go +++ b/pkg/tcpip/network/fragmentation/fragmentation.go @@ -81,8 +81,8 @@ func NewFragmentation(highMemoryLimit, lowMemoryLimit int, reassemblingTimeout t } } -// Process processes an incoming fragment belonging to an ID -// and returns a complete packet when all the packets belonging to that ID have been received. +// Process processes an incoming fragment belonging to an ID and returns a +// complete packet when all the packets belonging to that ID have been received. func (f *Fragmentation) Process(id uint32, first, last uint16, more bool, vv buffer.VectorisedView) (buffer.VectorisedView, bool, error) { f.mu.Lock() r, ok := f.reassemblers[id] diff --git a/pkg/tcpip/network/ip_test.go b/pkg/tcpip/network/ip_test.go index d9b62f2db..7c8fb3e0a 100644 --- a/pkg/tcpip/network/ip_test.go +++ b/pkg/tcpip/network/ip_test.go @@ -293,9 +293,9 @@ func TestIPv4Receive(t *testing.T) { if err != nil { t.Fatalf("could not find route: %v", err) } - ep.HandlePacket(&r, &stack.PacketBuffer{ - Data: view.ToVectorisedView(), - }) + pkt := stack.PacketBuffer{Data: view.ToVectorisedView()} + proto.Parse(&pkt) + ep.HandlePacket(&r, &pkt) if o.dataCalls != 1 { t.Fatalf("Bad number of data calls: got %x, want 1", o.dataCalls) } @@ -382,10 +382,7 @@ func TestIPv4ReceiveControl(t *testing.T) { o.typ = c.expectedTyp o.extra = c.expectedExtra - vv := view[:len(view)-c.trunc].ToVectorisedView() - ep.HandlePacket(&r, &stack.PacketBuffer{ - Data: vv, - }) + ep.HandlePacket(&r, truncatedPacket(view, c.trunc, header.IPv4MinimumSize)) if want := c.expectedCount; o.controlCalls != want { t.Fatalf("Bad number of control calls for %q case: got %v, want %v", c.name, o.controlCalls, want) } @@ -448,17 +445,17 @@ func TestIPv4FragmentationReceive(t *testing.T) { } // Send first segment. - ep.HandlePacket(&r, &stack.PacketBuffer{ - Data: frag1.ToVectorisedView(), - }) + pkt := stack.PacketBuffer{Data: frag1.ToVectorisedView()} + proto.Parse(&pkt) + ep.HandlePacket(&r, &pkt) if o.dataCalls != 0 { t.Fatalf("Bad number of data calls: got %x, want 0", o.dataCalls) } // Send second segment. - ep.HandlePacket(&r, &stack.PacketBuffer{ - Data: frag2.ToVectorisedView(), - }) + pkt = stack.PacketBuffer{Data: frag2.ToVectorisedView()} + proto.Parse(&pkt) + ep.HandlePacket(&r, &pkt) if o.dataCalls != 1 { t.Fatalf("Bad number of data calls: got %x, want 1", o.dataCalls) } @@ -538,9 +535,9 @@ func TestIPv6Receive(t *testing.T) { t.Fatalf("could not find route: %v", err) } - ep.HandlePacket(&r, &stack.PacketBuffer{ - Data: view.ToVectorisedView(), - }) + pkt := stack.PacketBuffer{Data: view.ToVectorisedView()} + proto.Parse(&pkt) + ep.HandlePacket(&r, &pkt) if o.dataCalls != 1 { t.Fatalf("Bad number of data calls: got %x, want 1", o.dataCalls) } @@ -652,12 +649,25 @@ func TestIPv6ReceiveControl(t *testing.T) { // Set ICMPv6 checksum. icmp.SetChecksum(header.ICMPv6Checksum(icmp, outerSrcAddr, localIpv6Addr, buffer.VectorisedView{})) - ep.HandlePacket(&r, &stack.PacketBuffer{ - Data: view[:len(view)-c.trunc].ToVectorisedView(), - }) + ep.HandlePacket(&r, truncatedPacket(view, c.trunc, header.IPv6MinimumSize)) if want := c.expectedCount; o.controlCalls != want { t.Fatalf("Bad number of control calls for %q case: got %v, want %v", c.name, o.controlCalls, want) } }) } } + +// truncatedPacket returns a PacketBuffer based on a truncated view. If view, +// after truncation, is large enough to hold a network header, it makes part of +// view the packet's NetworkHeader and the rest its Data. Otherwise all of view +// becomes Data. +func truncatedPacket(view buffer.View, trunc, netHdrLen int) *stack.PacketBuffer { + v := view[:len(view)-trunc] + if len(v) < netHdrLen { + return &stack.PacketBuffer{Data: v.ToVectorisedView()} + } + return &stack.PacketBuffer{ + NetworkHeader: v[:netHdrLen], + Data: v[netHdrLen:].ToVectorisedView(), + } +} diff --git a/pkg/tcpip/network/ipv4/icmp.go b/pkg/tcpip/network/ipv4/icmp.go index d1c3ae835..1b67aa066 100644 --- a/pkg/tcpip/network/ipv4/icmp.go +++ b/pkg/tcpip/network/ipv4/icmp.go @@ -59,6 +59,9 @@ func (e *endpoint) handleControl(typ stack.ControlType, extra uint32, pkt *stack func (e *endpoint) handleICMP(r *stack.Route, pkt *stack.PacketBuffer) { stats := r.Stats() received := stats.ICMP.V4PacketsReceived + // TODO(gvisor.dev/issue/170): ICMP packets don't have their + // TransportHeader fields set. See icmp/protocol.go:protocol.Parse for a + // full explanation. v, ok := pkt.Data.PullUp(header.ICMPv4MinimumSize) if !ok { received.Invalid.Increment() diff --git a/pkg/tcpip/network/ipv4/ipv4.go b/pkg/tcpip/network/ipv4/ipv4.go index 959f7e007..7e9f16c90 100644 --- a/pkg/tcpip/network/ipv4/ipv4.go +++ b/pkg/tcpip/network/ipv4/ipv4.go @@ -21,6 +21,7 @@ package ipv4 import ( + "fmt" "sync/atomic" "gvisor.dev/gvisor/pkg/tcpip" @@ -268,14 +269,14 @@ func (e *endpoint) WritePacket(r *stack.Route, gso *stack.GSO, params stack.Netw ep, err := e.stack.FindNetworkEndpoint(header.IPv4ProtocolNumber, netHeader.DestinationAddress()) if err == nil { route := r.ReverseRoute(netHeader.SourceAddress(), netHeader.DestinationAddress()) - handleLoopback(&route, pkt, ep) + ep.HandlePacket(&route, pkt) return nil } } if r.Loop&stack.PacketLoop != 0 { loopedR := r.MakeLoopedRoute() - handleLoopback(&loopedR, pkt, e) + e.HandlePacket(&loopedR, pkt) loopedR.Release() } if r.Loop&stack.PacketOut == 0 { @@ -291,17 +292,6 @@ func (e *endpoint) WritePacket(r *stack.Route, gso *stack.GSO, params stack.Netw return nil } -func handleLoopback(route *stack.Route, pkt *stack.PacketBuffer, ep stack.NetworkEndpoint) { - // The inbound path expects the network header to still be in - // the PacketBuffer's Data field. - views := make([]buffer.View, 1, 1+len(pkt.Data.Views())) - views[0] = pkt.Header.View() - views = append(views, pkt.Data.Views()...) - ep.HandlePacket(route, &stack.PacketBuffer{ - Data: buffer.NewVectorisedView(len(views[0])+pkt.Data.Size(), views), - }) -} - // WritePackets implements stack.NetworkEndpoint.WritePackets. func (e *endpoint) WritePackets(r *stack.Route, gso *stack.GSO, pkts stack.PacketBufferList, params stack.NetworkHeaderParams) (int, *tcpip.Error) { if r.Loop&stack.PacketLoop != 0 { @@ -339,12 +329,11 @@ func (e *endpoint) WritePackets(r *stack.Route, gso *stack.GSO, pkts stack.Packe } if _, ok := natPkts[pkt]; ok { netHeader := header.IPv4(pkt.NetworkHeader) - ep, err := e.stack.FindNetworkEndpoint(header.IPv4ProtocolNumber, netHeader.DestinationAddress()) - if err == nil { + if ep, err := e.stack.FindNetworkEndpoint(header.IPv4ProtocolNumber, netHeader.DestinationAddress()); err == nil { src := netHeader.SourceAddress() dst := netHeader.DestinationAddress() route := r.ReverseRoute(src, dst) - handleLoopback(&route, pkt, ep) + ep.HandlePacket(&route, pkt) n++ continue } @@ -418,22 +407,11 @@ func (e *endpoint) WriteHeaderIncludedPacket(r *stack.Route, pkt *stack.PacketBu // HandlePacket is called by the link layer when new ipv4 packets arrive for // this endpoint. func (e *endpoint) HandlePacket(r *stack.Route, pkt *stack.PacketBuffer) { - headerView, ok := pkt.Data.PullUp(header.IPv4MinimumSize) - if !ok { + h := header.IPv4(pkt.NetworkHeader) + if !h.IsValid(pkt.Data.Size() + len(pkt.NetworkHeader) + len(pkt.TransportHeader)) { r.Stats().IP.MalformedPacketsReceived.Increment() return } - h := header.IPv4(headerView) - if !h.IsValid(pkt.Data.Size()) { - r.Stats().IP.MalformedPacketsReceived.Increment() - return - } - pkt.NetworkHeader = headerView[:h.HeaderLength()] - - hlen := int(h.HeaderLength()) - tlen := int(h.TotalLength()) - pkt.Data.TrimFront(hlen) - pkt.Data.CapLength(tlen - hlen) // iptables filtering. All packets that reach here are intended for // this machine and will not be forwarded. @@ -443,9 +421,8 @@ func (e *endpoint) HandlePacket(r *stack.Route, pkt *stack.PacketBuffer) { return } - more := (h.Flags() & header.IPv4FlagMoreFragments) != 0 - if more || h.FragmentOffset() != 0 { - if pkt.Data.Size() == 0 { + if h.More() || h.FragmentOffset() != 0 { + if pkt.Data.Size()+len(pkt.TransportHeader) == 0 { // Drop the packet as it's marked as a fragment but has // no payload. r.Stats().IP.MalformedPacketsReceived.Increment() @@ -464,7 +441,7 @@ func (e *endpoint) HandlePacket(r *stack.Route, pkt *stack.PacketBuffer) { } var ready bool var err error - pkt.Data, ready, err = e.fragmentation.Process(hash.IPv4FragmentHash(h), h.FragmentOffset(), last, more, pkt.Data) + pkt.Data, ready, err = e.fragmentation.Process(hash.IPv4FragmentHash(h), h.FragmentOffset(), last, h.More(), pkt.Data) if err != nil { r.Stats().IP.MalformedPacketsReceived.Increment() r.Stats().IP.MalformedFragmentsReceived.Increment() @@ -476,7 +453,7 @@ func (e *endpoint) HandlePacket(r *stack.Route, pkt *stack.PacketBuffer) { } p := h.TransportProtocol() if p == header.ICMPv4ProtocolNumber { - headerView.CapLength(hlen) + pkt.NetworkHeader.CapLength(int(h.HeaderLength())) e.handleICMP(r, pkt) return } @@ -556,6 +533,35 @@ func (*protocol) Close() {} // Wait implements stack.TransportProtocol.Wait. func (*protocol) Wait() {} +// Parse implements stack.TransportProtocol.Parse. +func (*protocol) Parse(pkt *stack.PacketBuffer) (proto tcpip.TransportProtocolNumber, hasTransportHdr bool, ok bool) { + hdr, ok := pkt.Data.PullUp(header.IPv4MinimumSize) + if !ok { + return 0, false, false + } + ipHdr := header.IPv4(hdr) + + // If there are options, pull those into hdr as well. + if headerLen := int(ipHdr.HeaderLength()); headerLen > header.IPv4MinimumSize && headerLen <= pkt.Data.Size() { + hdr, ok = pkt.Data.PullUp(headerLen) + if !ok { + panic(fmt.Sprintf("There are only %d bytes in pkt.Data, but there should be at least %d", pkt.Data.Size(), headerLen)) + } + ipHdr = header.IPv4(hdr) + } + + // If this is a fragment, don't bother parsing the transport header. + parseTransportHeader := true + if ipHdr.More() || ipHdr.FragmentOffset() != 0 { + parseTransportHeader = false + } + + pkt.NetworkHeader = hdr + pkt.Data.TrimFront(len(hdr)) + pkt.Data.CapLength(int(ipHdr.TotalLength()) - len(hdr)) + return ipHdr.TransportProtocol(), parseTransportHeader, true +} + // calculateMTU calculates the network-layer payload MTU based on the link-layer // payload mtu. func calculateMTU(mtu uint32) uint32 { diff --git a/pkg/tcpip/network/ipv4/ipv4_test.go b/pkg/tcpip/network/ipv4/ipv4_test.go index c208ebd99..11e579c4b 100644 --- a/pkg/tcpip/network/ipv4/ipv4_test.go +++ b/pkg/tcpip/network/ipv4/ipv4_test.go @@ -652,6 +652,18 @@ func TestReceiveFragments(t *testing.T) { }, expectedPayloads: [][]byte{udpPayload1, udpPayload2}, }, + { + name: "Fragment without followup", + fragments: []fragmentData{ + { + id: 1, + flags: header.IPv4FlagMoreFragments, + fragmentOffset: 0, + payload: ipv4Payload1[:64], + }, + }, + expectedPayloads: nil, + }, } for _, test := range tests { diff --git a/pkg/tcpip/network/ipv6/icmp.go b/pkg/tcpip/network/ipv6/icmp.go index b62fb1de6..2ff7eedf4 100644 --- a/pkg/tcpip/network/ipv6/icmp.go +++ b/pkg/tcpip/network/ipv6/icmp.go @@ -70,17 +70,20 @@ func (e *endpoint) handleControl(typ stack.ControlType, extra uint32, pkt *stack e.dispatcher.DeliverTransportControlPacket(e.id.LocalAddress, hdr.DestinationAddress(), ProtocolNumber, p, typ, extra, pkt) } -func (e *endpoint) handleICMP(r *stack.Route, netHeader buffer.View, pkt *stack.PacketBuffer, hasFragmentHeader bool) { +func (e *endpoint) handleICMP(r *stack.Route, pkt *stack.PacketBuffer, hasFragmentHeader bool) { stats := r.Stats().ICMP sent := stats.V6PacketsSent received := stats.V6PacketsReceived + // TODO(gvisor.dev/issue/170): ICMP packets don't have their + // TransportHeader fields set. See icmp/protocol.go:protocol.Parse for a + // full explanation. v, ok := pkt.Data.PullUp(header.ICMPv6HeaderSize) if !ok { received.Invalid.Increment() return } h := header.ICMPv6(v) - iph := header.IPv6(netHeader) + iph := header.IPv6(pkt.NetworkHeader) // Validate ICMPv6 checksum before processing the packet. // diff --git a/pkg/tcpip/network/ipv6/icmp_test.go b/pkg/tcpip/network/ipv6/icmp_test.go index a720f626f..52a01b44e 100644 --- a/pkg/tcpip/network/ipv6/icmp_test.go +++ b/pkg/tcpip/network/ipv6/icmp_test.go @@ -179,36 +179,32 @@ func TestICMPCounts(t *testing.T) { }, } - handleIPv6Payload := func(hdr buffer.Prependable) { - payloadLength := hdr.UsedLength() - ip := header.IPv6(hdr.Prepend(header.IPv6MinimumSize)) + handleIPv6Payload := func(icmp header.ICMPv6) { + ip := header.IPv6(buffer.NewView(header.IPv6MinimumSize)) ip.Encode(&header.IPv6Fields{ - PayloadLength: uint16(payloadLength), + PayloadLength: uint16(len(icmp)), NextHeader: uint8(header.ICMPv6ProtocolNumber), HopLimit: header.NDPHopLimit, SrcAddr: r.LocalAddress, DstAddr: r.RemoteAddress, }) ep.HandlePacket(&r, &stack.PacketBuffer{ - Data: hdr.View().ToVectorisedView(), + NetworkHeader: buffer.View(ip), + Data: buffer.View(icmp).ToVectorisedView(), }) } for _, typ := range types { - extraDataLen := len(typ.extraData) - hdr := buffer.NewPrependable(header.IPv6MinimumSize + typ.size + extraDataLen) - extraData := buffer.View(hdr.Prepend(extraDataLen)) - copy(extraData, typ.extraData) - pkt := header.ICMPv6(hdr.Prepend(typ.size)) - pkt.SetType(typ.typ) - pkt.SetChecksum(header.ICMPv6Checksum(pkt, r.LocalAddress, r.RemoteAddress, extraData.ToVectorisedView())) - - handleIPv6Payload(hdr) + icmp := header.ICMPv6(buffer.NewView(typ.size + len(typ.extraData))) + copy(icmp[typ.size:], typ.extraData) + icmp.SetType(typ.typ) + icmp.SetChecksum(header.ICMPv6Checksum(icmp[:typ.size], r.LocalAddress, r.RemoteAddress, buffer.View(typ.extraData).ToVectorisedView())) + handleIPv6Payload(icmp) } // Construct an empty ICMP packet so that // Stats().ICMP.ICMPv6ReceivedPacketStats.Invalid is incremented. - handleIPv6Payload(buffer.NewPrependable(header.IPv6MinimumSize)) + handleIPv6Payload(header.ICMPv6(buffer.NewView(header.IPv6MinimumSize))) icmpv6Stats := s.Stats().ICMP.V6PacketsReceived visitStats(reflect.ValueOf(&icmpv6Stats).Elem(), func(name string, s *tcpip.StatCounter) { @@ -546,25 +542,22 @@ func TestICMPChecksumValidationSimple(t *testing.T) { } handleIPv6Payload := func(checksum bool) { - extraDataLen := len(typ.extraData) - hdr := buffer.NewPrependable(header.IPv6MinimumSize + typ.size + extraDataLen) - extraData := buffer.View(hdr.Prepend(extraDataLen)) - copy(extraData, typ.extraData) - pkt := header.ICMPv6(hdr.Prepend(typ.size)) - pkt.SetType(typ.typ) + icmp := header.ICMPv6(buffer.NewView(typ.size + len(typ.extraData))) + copy(icmp[typ.size:], typ.extraData) + icmp.SetType(typ.typ) if checksum { - pkt.SetChecksum(header.ICMPv6Checksum(pkt, lladdr1, lladdr0, extraData.ToVectorisedView())) + icmp.SetChecksum(header.ICMPv6Checksum(icmp, lladdr1, lladdr0, buffer.View{}.ToVectorisedView())) } - ip := header.IPv6(hdr.Prepend(header.IPv6MinimumSize)) + ip := header.IPv6(buffer.NewView(header.IPv6MinimumSize)) ip.Encode(&header.IPv6Fields{ - PayloadLength: uint16(typ.size + extraDataLen), + PayloadLength: uint16(len(icmp)), NextHeader: uint8(header.ICMPv6ProtocolNumber), HopLimit: header.NDPHopLimit, SrcAddr: lladdr1, DstAddr: lladdr0, }) e.InjectInbound(ProtocolNumber, &stack.PacketBuffer{ - Data: hdr.View().ToVectorisedView(), + Data: buffer.NewVectorisedView(len(ip)+len(icmp), []buffer.View{buffer.View(ip), buffer.View(icmp)}), }) } diff --git a/pkg/tcpip/network/ipv6/ipv6.go b/pkg/tcpip/network/ipv6/ipv6.go index 0d94ad122..95fbcf2d1 100644 --- a/pkg/tcpip/network/ipv6/ipv6.go +++ b/pkg/tcpip/network/ipv6/ipv6.go @@ -171,22 +171,20 @@ func (*endpoint) WriteHeaderIncludedPacket(r *stack.Route, pkt *stack.PacketBuff // HandlePacket is called by the link layer when new ipv6 packets arrive for // this endpoint. func (e *endpoint) HandlePacket(r *stack.Route, pkt *stack.PacketBuffer) { - headerView, ok := pkt.Data.PullUp(header.IPv6MinimumSize) - if !ok { + h := header.IPv6(pkt.NetworkHeader) + if !h.IsValid(pkt.Data.Size() + len(pkt.NetworkHeader) + len(pkt.TransportHeader)) { r.Stats().IP.MalformedPacketsReceived.Increment() return } - h := header.IPv6(headerView) - if !h.IsValid(pkt.Data.Size()) { - r.Stats().IP.MalformedPacketsReceived.Increment() - return - } - - pkt.NetworkHeader = headerView[:header.IPv6MinimumSize] - pkt.Data.TrimFront(header.IPv6MinimumSize) - pkt.Data.CapLength(int(h.PayloadLength())) - it := header.MakeIPv6PayloadIterator(header.IPv6ExtensionHeaderIdentifier(h.NextHeader()), pkt.Data) + // vv consists of: + // - Any IPv6 header bytes after the first 40 (i.e. extensions). + // - The transport header, if present. + // - Any other payload data. + vv := pkt.NetworkHeader[header.IPv6MinimumSize:].ToVectorisedView() + vv.AppendView(pkt.TransportHeader) + vv.Append(pkt.Data) + it := header.MakeIPv6PayloadIterator(header.IPv6ExtensionHeaderIdentifier(h.NextHeader()), vv) hasFragmentHeader := false for firstHeader := true; ; firstHeader = false { @@ -262,9 +260,7 @@ func (e *endpoint) HandlePacket(r *stack.Route, pkt *stack.PacketBuffer) { case header.IPv6FragmentExtHdr: hasFragmentHeader = true - fragmentOffset := extHdr.FragmentOffset() - more := extHdr.More() - if !more && fragmentOffset == 0 { + if extHdr.IsAtomic() { // This fragment extension header indicates that this packet is an // atomic fragment. An atomic fragment is a fragment that contains // all the data required to reassemble a full packet. As per RFC 6946, @@ -277,9 +273,9 @@ func (e *endpoint) HandlePacket(r *stack.Route, pkt *stack.PacketBuffer) { // Don't consume the iterator if we have the first fragment because we // will use it to validate that the first fragment holds the upper layer // header. - rawPayload := it.AsRawHeader(fragmentOffset != 0 /* consume */) + rawPayload := it.AsRawHeader(extHdr.FragmentOffset() != 0 /* consume */) - if fragmentOffset == 0 { + if extHdr.FragmentOffset() == 0 { // Check that the iterator ends with a raw payload as the first fragment // should include all headers up to and including any upper layer // headers, as per RFC 8200 section 4.5; only upper layer data @@ -332,7 +328,7 @@ func (e *endpoint) HandlePacket(r *stack.Route, pkt *stack.PacketBuffer) { } // The packet is a fragment, let's try to reassemble it. - start := fragmentOffset * header.IPv6FragmentExtHdrFragmentOffsetBytesPerUnit + start := extHdr.FragmentOffset() * header.IPv6FragmentExtHdrFragmentOffsetBytesPerUnit last := start + uint16(fragmentPayloadLen) - 1 // Drop the packet if the fragmentOffset is incorrect. i.e the @@ -345,7 +341,9 @@ func (e *endpoint) HandlePacket(r *stack.Route, pkt *stack.PacketBuffer) { } var ready bool - pkt.Data, ready, err = e.fragmentation.Process(hash.IPv6FragmentHash(h, extHdr.ID()), start, last, more, rawPayload.Buf) + // Note that pkt doesn't have its transport header set after reassembly, + // and won't until DeliverNetworkPacket sets it. + pkt.Data, ready, err = e.fragmentation.Process(hash.IPv6FragmentHash(h, extHdr.ID()), start, last, extHdr.More(), rawPayload.Buf) if err != nil { r.Stats().IP.MalformedPacketsReceived.Increment() r.Stats().IP.MalformedFragmentsReceived.Increment() @@ -394,10 +392,17 @@ func (e *endpoint) HandlePacket(r *stack.Route, pkt *stack.PacketBuffer) { case header.IPv6RawPayloadHeader: // If the last header in the payload isn't a known IPv6 extension header, // handle it as if it is transport layer data. + + // For unfragmented packets, extHdr still contains the transport header. + // Get rid of it. + // + // For reassembled fragments, pkt.TransportHeader is unset, so this is a + // no-op and pkt.Data begins with the transport header. + extHdr.Buf.TrimFront(len(pkt.TransportHeader)) pkt.Data = extHdr.Buf if p := tcpip.TransportProtocolNumber(extHdr.Identifier); p == header.ICMPv6ProtocolNumber { - e.handleICMP(r, headerView, pkt, hasFragmentHeader) + e.handleICMP(r, pkt, hasFragmentHeader) } else { r.Stats().IP.PacketsDelivered.Increment() // TODO(b/152019344): Send an ICMPv6 Parameter Problem, Code 1 error @@ -505,6 +510,79 @@ func (*protocol) Close() {} // Wait implements stack.TransportProtocol.Wait. func (*protocol) Wait() {} +// Parse implements stack.TransportProtocol.Parse. +func (*protocol) Parse(pkt *stack.PacketBuffer) (proto tcpip.TransportProtocolNumber, hasTransportHdr bool, ok bool) { + hdr, ok := pkt.Data.PullUp(header.IPv6MinimumSize) + if !ok { + return 0, false, false + } + ipHdr := header.IPv6(hdr) + + // dataClone consists of: + // - Any IPv6 header bytes after the first 40 (i.e. extensions). + // - The transport header, if present. + // - Any other payload data. + views := [8]buffer.View{} + dataClone := pkt.Data.Clone(views[:]) + dataClone.TrimFront(header.IPv6MinimumSize) + it := header.MakeIPv6PayloadIterator(header.IPv6ExtensionHeaderIdentifier(ipHdr.NextHeader()), dataClone) + + // Iterate over the IPv6 extensions to find their length. + // + // Parsing occurs again in HandlePacket because we don't track the + // extensions in PacketBuffer. Unfortunately, that means HandlePacket + // has to do the parsing work again. + var nextHdr tcpip.TransportProtocolNumber + foundNext := true + extensionsSize := 0 +traverseExtensions: + for extHdr, done, err := it.Next(); ; extHdr, done, err = it.Next() { + if err != nil { + break + } + // If we exhaust the extension list, the entire packet is the IPv6 header + // and (possibly) extensions. + if done { + extensionsSize = dataClone.Size() + foundNext = false + break + } + + switch extHdr := extHdr.(type) { + case header.IPv6FragmentExtHdr: + // If this is an atomic fragment, we don't have to treat it specially. + if !extHdr.More() && extHdr.FragmentOffset() == 0 { + continue + } + // This is a non-atomic fragment and has to be re-assembled before we can + // examine the payload for a transport header. + foundNext = false + + case header.IPv6RawPayloadHeader: + // We've found the payload after any extensions. + extensionsSize = dataClone.Size() - extHdr.Buf.Size() + nextHdr = tcpip.TransportProtocolNumber(extHdr.Identifier) + break traverseExtensions + + default: + // Any other extension is a no-op, keep looping until we find the payload. + } + } + + // Put the IPv6 header with extensions in pkt.NetworkHeader. + hdr, ok = pkt.Data.PullUp(header.IPv6MinimumSize + extensionsSize) + if !ok { + panic(fmt.Sprintf("pkt.Data should have at least %d bytes, but only has %d.", header.IPv6MinimumSize+extensionsSize, pkt.Data.Size())) + } + ipHdr = header.IPv6(hdr) + + pkt.NetworkHeader = hdr + pkt.Data.TrimFront(len(hdr)) + pkt.Data.CapLength(int(ipHdr.PayloadLength())) + + return nextHdr, foundNext, true +} + // calculateMTU calculates the network-layer payload MTU based on the link-layer // payload mtu. func calculateMTU(mtu uint32) uint32 { diff --git a/pkg/tcpip/network/ipv6/ndp_test.go b/pkg/tcpip/network/ipv6/ndp_test.go index 3c141b91b..64239ce9a 100644 --- a/pkg/tcpip/network/ipv6/ndp_test.go +++ b/pkg/tcpip/network/ipv6/ndp_test.go @@ -551,25 +551,29 @@ func TestNDPValidation(t *testing.T) { return s, ep, r } - handleIPv6Payload := func(hdr buffer.Prependable, hopLimit uint8, atomicFragment bool, ep stack.NetworkEndpoint, r *stack.Route) { + handleIPv6Payload := func(payload buffer.View, hopLimit uint8, atomicFragment bool, ep stack.NetworkEndpoint, r *stack.Route) { nextHdr := uint8(header.ICMPv6ProtocolNumber) + var extensions buffer.View if atomicFragment { - bytes := hdr.Prepend(header.IPv6FragmentExtHdrLength) - bytes[0] = nextHdr + extensions = buffer.NewView(header.IPv6FragmentExtHdrLength) + extensions[0] = nextHdr nextHdr = uint8(header.IPv6FragmentExtHdrIdentifier) } - payloadLength := hdr.UsedLength() - ip := header.IPv6(hdr.Prepend(header.IPv6MinimumSize)) + ip := header.IPv6(buffer.NewView(header.IPv6MinimumSize + len(extensions))) ip.Encode(&header.IPv6Fields{ - PayloadLength: uint16(payloadLength), + PayloadLength: uint16(len(payload) + len(extensions)), NextHeader: nextHdr, HopLimit: hopLimit, SrcAddr: r.LocalAddress, DstAddr: r.RemoteAddress, }) + if n := copy(ip[header.IPv6MinimumSize:], extensions); n != len(extensions) { + t.Fatalf("expected to write %d bytes of extensions, but wrote %d", len(extensions), n) + } ep.HandlePacket(r, &stack.PacketBuffer{ - Data: hdr.View().ToVectorisedView(), + NetworkHeader: buffer.View(ip), + Data: payload.ToVectorisedView(), }) } @@ -676,14 +680,11 @@ func TestNDPValidation(t *testing.T) { invalid := stats.Invalid typStat := typ.statCounter(stats) - extraDataLen := len(typ.extraData) - hdr := buffer.NewPrependable(header.IPv6MinimumSize + typ.size + extraDataLen + header.IPv6FragmentExtHdrLength) - extraData := buffer.View(hdr.Prepend(extraDataLen)) - copy(extraData, typ.extraData) - pkt := header.ICMPv6(hdr.Prepend(typ.size)) - pkt.SetType(typ.typ) - pkt.SetCode(test.code) - pkt.SetChecksum(header.ICMPv6Checksum(pkt, r.LocalAddress, r.RemoteAddress, extraData.ToVectorisedView())) + icmp := header.ICMPv6(buffer.NewView(typ.size + len(typ.extraData))) + copy(icmp[typ.size:], typ.extraData) + icmp.SetType(typ.typ) + icmp.SetCode(test.code) + icmp.SetChecksum(header.ICMPv6Checksum(icmp[:typ.size], r.LocalAddress, r.RemoteAddress, buffer.View(typ.extraData).ToVectorisedView())) // Rx count of the NDP message should initially be 0. if got := typStat.Value(); got != 0 { @@ -699,7 +700,7 @@ func TestNDPValidation(t *testing.T) { t.FailNow() } - handleIPv6Payload(hdr, test.hopLimit, test.atomicFragment, ep, &r) + handleIPv6Payload(buffer.View(icmp), test.hopLimit, test.atomicFragment, ep, &r) // Rx count of the NDP packet should have increased. if got := typStat.Value(); got != 1 { diff --git a/pkg/tcpip/stack/conntrack.go b/pkg/tcpip/stack/conntrack.go index d4053be08..05bf62788 100644 --- a/pkg/tcpip/stack/conntrack.go +++ b/pkg/tcpip/stack/conntrack.go @@ -20,7 +20,6 @@ import ( "time" "gvisor.dev/gvisor/pkg/tcpip" - "gvisor.dev/gvisor/pkg/tcpip/buffer" "gvisor.dev/gvisor/pkg/tcpip/hash/jenkins" "gvisor.dev/gvisor/pkg/tcpip/header" "gvisor.dev/gvisor/pkg/tcpip/transport/tcpconntrack" @@ -147,44 +146,6 @@ type ConnTrackTable struct { Seed uint32 } -// parseHeaders sets headers in the packet. -func parseHeaders(pkt *PacketBuffer) { - newPkt := pkt.Clone() - - // Set network header. - hdr, ok := newPkt.Data.PullUp(header.IPv4MinimumSize) - if !ok { - return - } - netHeader := header.IPv4(hdr) - newPkt.NetworkHeader = hdr - length := int(netHeader.HeaderLength()) - - // TODO(gvisor.dev/issue/170): Need to support for other - // protocols as well. - // Set transport header. - switch protocol := netHeader.TransportProtocol(); protocol { - case header.UDPProtocolNumber: - if newPkt.TransportHeader == nil { - h, ok := newPkt.Data.PullUp(length + header.UDPMinimumSize) - if !ok { - return - } - newPkt.TransportHeader = buffer.View(header.UDP(h[length:])) - } - case header.TCPProtocolNumber: - if newPkt.TransportHeader == nil { - h, ok := newPkt.Data.PullUp(length + header.TCPMinimumSize) - if !ok { - return - } - newPkt.TransportHeader = buffer.View(header.TCP(h[length:])) - } - } - pkt.NetworkHeader = newPkt.NetworkHeader - pkt.TransportHeader = newPkt.TransportHeader -} - // packetToTuple converts packet to a tuple in original direction. func packetToTuple(pkt *PacketBuffer, hook Hook) (connTrackTuple, *tcpip.Error) { var tuple connTrackTuple @@ -257,13 +218,6 @@ func (ct *ConnTrackTable) getTupleHash(tuple connTrackTuple) uint32 { // TODO(gvisor.dev/issue/170): Only TCP packets are supported. Need to support other // transport protocols. func (ct *ConnTrackTable) connTrackForPacket(pkt *PacketBuffer, hook Hook, createConn bool) (*connTrack, ctDirection) { - if hook == Prerouting { - // Headers will not be set in Prerouting. - // TODO(gvisor.dev/issue/170): Change this after parsing headers - // code is added. - parseHeaders(pkt) - } - var dir ctDirection tuple, err := packetToTuple(pkt, hook) if err != nil { diff --git a/pkg/tcpip/stack/forwarder_test.go b/pkg/tcpip/stack/forwarder_test.go index 63537aaad..a6546cef0 100644 --- a/pkg/tcpip/stack/forwarder_test.go +++ b/pkg/tcpip/stack/forwarder_test.go @@ -33,6 +33,10 @@ const ( // except where another value is explicitly used. It is chosen to match // the MTU of loopback interfaces on linux systems. fwdTestNetDefaultMTU = 65536 + + dstAddrOffset = 0 + srcAddrOffset = 1 + protocolNumberOffset = 2 ) // fwdTestNetworkEndpoint is a network-layer protocol endpoint. @@ -69,15 +73,8 @@ func (f *fwdTestNetworkEndpoint) ID() *NetworkEndpointID { } func (f *fwdTestNetworkEndpoint) HandlePacket(r *Route, pkt *PacketBuffer) { - // Consume the network header. - b, ok := pkt.Data.PullUp(fwdTestNetHeaderLen) - if !ok { - return - } - pkt.Data.TrimFront(fwdTestNetHeaderLen) - // Dispatch the packet to the transport protocol. - f.dispatcher.DeliverTransportPacket(r, tcpip.TransportProtocolNumber(b[2]), pkt) + f.dispatcher.DeliverTransportPacket(r, tcpip.TransportProtocolNumber(pkt.NetworkHeader[protocolNumberOffset]), pkt) } func (f *fwdTestNetworkEndpoint) MaxHeaderLength() uint16 { @@ -100,9 +97,9 @@ func (f *fwdTestNetworkEndpoint) WritePacket(r *Route, gso *GSO, params NetworkH // Add the protocol's header to the packet and send it to the link // endpoint. b := pkt.Header.Prepend(fwdTestNetHeaderLen) - b[0] = r.RemoteAddress[0] - b[1] = f.id.LocalAddress[0] - b[2] = byte(params.Protocol) + b[dstAddrOffset] = r.RemoteAddress[0] + b[srcAddrOffset] = f.id.LocalAddress[0] + b[protocolNumberOffset] = byte(params.Protocol) return f.ep.WritePacket(r, gso, fwdTestNetNumber, pkt) } @@ -140,7 +137,17 @@ func (f *fwdTestNetworkProtocol) DefaultPrefixLen() int { } func (*fwdTestNetworkProtocol) ParseAddresses(v buffer.View) (src, dst tcpip.Address) { - return tcpip.Address(v[1:2]), tcpip.Address(v[0:1]) + return tcpip.Address(v[srcAddrOffset : srcAddrOffset+1]), tcpip.Address(v[dstAddrOffset : dstAddrOffset+1]) +} + +func (*fwdTestNetworkProtocol) Parse(pkt *PacketBuffer) (tcpip.TransportProtocolNumber, bool, bool) { + netHeader, ok := pkt.Data.PullUp(fwdTestNetHeaderLen) + if !ok { + return 0, false, false + } + pkt.NetworkHeader = netHeader + pkt.Data.TrimFront(fwdTestNetHeaderLen) + return tcpip.TransportProtocolNumber(pkt.NetworkHeader[protocolNumberOffset]), true, true } func (f *fwdTestNetworkProtocol) NewEndpoint(nicID tcpip.NICID, addrWithPrefix tcpip.AddressWithPrefix, linkAddrCache LinkAddressCache, dispatcher TransportDispatcher, ep LinkEndpoint, _ *Stack) (NetworkEndpoint, *tcpip.Error) { @@ -361,7 +368,7 @@ func TestForwardingWithStaticResolver(t *testing.T) { // Inject an inbound packet to address 3 on NIC 1, and see if it is // forwarded to NIC 2. buf := buffer.NewView(30) - buf[0] = 3 + buf[dstAddrOffset] = 3 ep1.InjectInbound(fwdTestNetNumber, &PacketBuffer{ Data: buf.ToVectorisedView(), }) @@ -398,7 +405,7 @@ func TestForwardingWithFakeResolver(t *testing.T) { // Inject an inbound packet to address 3 on NIC 1, and see if it is // forwarded to NIC 2. buf := buffer.NewView(30) - buf[0] = 3 + buf[dstAddrOffset] = 3 ep1.InjectInbound(fwdTestNetNumber, &PacketBuffer{ Data: buf.ToVectorisedView(), }) @@ -429,7 +436,7 @@ func TestForwardingWithNoResolver(t *testing.T) { // inject an inbound packet to address 3 on NIC 1, and see if it is // forwarded to NIC 2. buf := buffer.NewView(30) - buf[0] = 3 + buf[dstAddrOffset] = 3 ep1.InjectInbound(fwdTestNetNumber, &PacketBuffer{ Data: buf.ToVectorisedView(), }) @@ -459,7 +466,7 @@ func TestForwardingWithFakeResolverPartialTimeout(t *testing.T) { // Inject an inbound packet to address 4 on NIC 1. This packet should // not be forwarded. buf := buffer.NewView(30) - buf[0] = 4 + buf[dstAddrOffset] = 4 ep1.InjectInbound(fwdTestNetNumber, &PacketBuffer{ Data: buf.ToVectorisedView(), }) @@ -467,7 +474,7 @@ func TestForwardingWithFakeResolverPartialTimeout(t *testing.T) { // Inject an inbound packet to address 3 on NIC 1, and see if it is // forwarded to NIC 2. buf = buffer.NewView(30) - buf[0] = 3 + buf[dstAddrOffset] = 3 ep1.InjectInbound(fwdTestNetNumber, &PacketBuffer{ Data: buf.ToVectorisedView(), }) @@ -480,9 +487,8 @@ func TestForwardingWithFakeResolverPartialTimeout(t *testing.T) { t.Fatal("packet not forwarded") } - b := p.Pkt.Data.ToView() - if b[0] != 3 { - t.Fatalf("got b[0] = %d, want = 3", b[0]) + if p.Pkt.NetworkHeader[dstAddrOffset] != 3 { + t.Fatalf("got p.Pkt.NetworkHeader[dstAddrOffset] = %d, want = 3", p.Pkt.NetworkHeader[dstAddrOffset]) } // Test that the address resolution happened correctly. @@ -509,7 +515,7 @@ func TestForwardingWithFakeResolverTwoPackets(t *testing.T) { // Inject two inbound packets to address 3 on NIC 1. for i := 0; i < 2; i++ { buf := buffer.NewView(30) - buf[0] = 3 + buf[dstAddrOffset] = 3 ep1.InjectInbound(fwdTestNetNumber, &PacketBuffer{ Data: buf.ToVectorisedView(), }) @@ -524,9 +530,8 @@ func TestForwardingWithFakeResolverTwoPackets(t *testing.T) { t.Fatal("packet not forwarded") } - b := p.Pkt.Data.ToView() - if b[0] != 3 { - t.Fatalf("got b[0] = %d, want = 3", b[0]) + if p.Pkt.NetworkHeader[dstAddrOffset] != 3 { + t.Fatalf("got p.Pkt.NetworkHeader[dstAddrOffset] = %d, want = 3", p.Pkt.NetworkHeader[dstAddrOffset]) } // Test that the address resolution happened correctly. @@ -554,7 +559,7 @@ func TestForwardingWithFakeResolverManyPackets(t *testing.T) { for i := 0; i < maxPendingPacketsPerResolution+5; i++ { // Inject inbound 'maxPendingPacketsPerResolution + 5' packets on NIC 1. buf := buffer.NewView(30) - buf[0] = 3 + buf[dstAddrOffset] = 3 // Set the packet sequence number. binary.BigEndian.PutUint16(buf[fwdTestNetHeaderLen:], uint16(i)) ep1.InjectInbound(fwdTestNetNumber, &PacketBuffer{ @@ -571,14 +576,18 @@ func TestForwardingWithFakeResolverManyPackets(t *testing.T) { t.Fatal("packet not forwarded") } - b := p.Pkt.Data.ToView() - if b[0] != 3 { - t.Fatalf("got b[0] = %d, want = 3", b[0]) + if b := p.Pkt.Header.View(); b[dstAddrOffset] != 3 { + t.Fatalf("got b[dstAddrOffset] = %d, want = 3", b[dstAddrOffset]) + } + seqNumBuf, ok := p.Pkt.Data.PullUp(2) // The sequence number is a uint16 (2 bytes). + if !ok { + t.Fatalf("p.Pkt.Data is too short to hold a sequence number: %d", p.Pkt.Data.Size()) } - // The first 5 packets should not be forwarded so the the - // sequemnce number should start with 5. + + // The first 5 packets should not be forwarded so the sequence number should + // start with 5. want := uint16(i + 5) - if n := binary.BigEndian.Uint16(b[fwdTestNetHeaderLen:]); n != want { + if n := binary.BigEndian.Uint16(seqNumBuf); n != want { t.Fatalf("got the packet #%d, want = #%d", n, want) } @@ -609,7 +618,7 @@ func TestForwardingWithFakeResolverManyResolutions(t *testing.T) { // Each packet has a different destination address (3 to // maxPendingResolutions + 7). buf := buffer.NewView(30) - buf[0] = byte(3 + i) + buf[dstAddrOffset] = byte(3 + i) ep1.InjectInbound(fwdTestNetNumber, &PacketBuffer{ Data: buf.ToVectorisedView(), }) @@ -626,9 +635,8 @@ func TestForwardingWithFakeResolverManyResolutions(t *testing.T) { // The first 5 packets (address 3 to 7) should not be forwarded // because their address resolutions are interrupted. - b := p.Pkt.Data.ToView() - if b[0] < 8 { - t.Fatalf("got b[0] = %d, want b[0] >= 8", b[0]) + if p.Pkt.NetworkHeader[dstAddrOffset] < 8 { + t.Fatalf("got p.Pkt.NetworkHeader[dstAddrOffset] = %d, want p.Pkt.NetworkHeader[dstAddrOffset] >= 8", p.Pkt.NetworkHeader[dstAddrOffset]) } // Test that the address resolution happened correctly. diff --git a/pkg/tcpip/stack/iptables_targets.go b/pkg/tcpip/stack/iptables_targets.go index 36cc6275d..92e31643e 100644 --- a/pkg/tcpip/stack/iptables_targets.go +++ b/pkg/tcpip/stack/iptables_targets.go @@ -98,11 +98,6 @@ func (rt RedirectTarget) Action(pkt *PacketBuffer, ct *ConnTrackTable, hook Hook return RuleAccept, 0 } - // Set network header. - if hook == Prerouting { - parseHeaders(pkt) - } - // Drop the packet if network and transport header are not set. if pkt.NetworkHeader == nil || pkt.TransportHeader == nil { return RuleDrop, 0 diff --git a/pkg/tcpip/stack/nic.go b/pkg/tcpip/stack/nic.go index 6664aea06..d756ae6f5 100644 --- a/pkg/tcpip/stack/nic.go +++ b/pkg/tcpip/stack/nic.go @@ -1212,12 +1212,21 @@ func (n *NIC) DeliverNetworkPacket(remote, local tcpip.LinkAddress, protocol tcp n.stack.stats.IP.PacketsReceived.Increment() } - netHeader, ok := pkt.Data.PullUp(netProto.MinimumPacketSize()) + // Parse headers. + transProtoNum, hasTransportHdr, ok := netProto.Parse(pkt) if !ok { + // The packet is too small to contain a network header. n.stack.stats.MalformedRcvdPackets.Increment() return } - src, dst := netProto.ParseAddresses(netHeader) + if hasTransportHdr { + // Parse the transport header if present. + if state, ok := n.stack.transportProtocols[transProtoNum]; ok { + state.proto.Parse(pkt) + } + } + + src, dst := netProto.ParseAddresses(pkt.NetworkHeader) if n.stack.handleLocal && !n.isLoopback() && n.getRef(protocol, src) != nil { // The source address is one of our own, so we never should have gotten a @@ -1301,8 +1310,18 @@ func (n *NIC) DeliverNetworkPacket(remote, local tcpip.LinkAddress, protocol tcp func (n *NIC) forwardPacket(r *Route, protocol tcpip.NetworkProtocolNumber, pkt *PacketBuffer) { // TODO(b/143425874) Decrease the TTL field in forwarded packets. - if linkHeaderLen := int(n.linkEP.MaxHeaderLength()); linkHeaderLen != 0 { - pkt.Header = buffer.NewPrependable(linkHeaderLen) + // TODO(b/151227689): Avoid copying the packet when forwarding. We can do this + // by having lower layers explicity write each header instead of just + // pkt.Header. + + // pkt may have set its NetworkHeader and TransportHeader. If we're + // forwarding, we'll have to copy them into pkt.Header. + pkt.Header = buffer.NewPrependable(int(n.linkEP.MaxHeaderLength()) + len(pkt.NetworkHeader) + len(pkt.TransportHeader)) + if n := copy(pkt.Header.Prepend(len(pkt.TransportHeader)), pkt.TransportHeader); n != len(pkt.TransportHeader) { + panic(fmt.Sprintf("copied %d bytes, expected %d", n, len(pkt.TransportHeader))) + } + if n := copy(pkt.Header.Prepend(len(pkt.NetworkHeader)), pkt.NetworkHeader); n != len(pkt.NetworkHeader) { + panic(fmt.Sprintf("copied %d bytes, expected %d", n, len(pkt.NetworkHeader))) } // WritePacket takes ownership of pkt, calculate numBytes first. @@ -1333,13 +1352,31 @@ func (n *NIC) DeliverTransportPacket(r *Route, protocol tcpip.TransportProtocolN // validly formed. n.stack.demux.deliverRawPacket(r, protocol, pkt) - transHeader, ok := pkt.Data.PullUp(transProto.MinimumPacketSize()) - if !ok { + // TransportHeader is nil only when pkt is an ICMP packet or was reassembled + // from fragments. + if pkt.TransportHeader == nil { + // TODO(gvisor.dev/issue/170): ICMP packets don't have their + // TransportHeader fields set. See icmp/protocol.go:protocol.Parse for a + // full explanation. + if protocol == header.ICMPv4ProtocolNumber || protocol == header.ICMPv6ProtocolNumber { + transHeader, ok := pkt.Data.PullUp(transProto.MinimumPacketSize()) + if !ok { + n.stack.stats.MalformedRcvdPackets.Increment() + return + } + pkt.TransportHeader = transHeader + } else { + // This is either a bad packet or was re-assembled from fragments. + transProto.Parse(pkt) + } + } + + if len(pkt.TransportHeader) < transProto.MinimumPacketSize() { n.stack.stats.MalformedRcvdPackets.Increment() return } - srcPort, dstPort, err := transProto.ParsePorts(transHeader) + srcPort, dstPort, err := transProto.ParsePorts(pkt.TransportHeader) if err != nil { n.stack.stats.MalformedRcvdPackets.Increment() return diff --git a/pkg/tcpip/stack/registration.go b/pkg/tcpip/stack/registration.go index 94f177841..5cbc946b6 100644 --- a/pkg/tcpip/stack/registration.go +++ b/pkg/tcpip/stack/registration.go @@ -168,6 +168,11 @@ type TransportProtocol interface { // Wait waits for any worker goroutines owned by the protocol to stop. Wait() + + // Parse sets pkt.TransportHeader and trims pkt.Data appropriately. It does + // neither and returns false if pkt.Data is too small, i.e. pkt.Data.Size() < + // MinimumPacketSize() + Parse(pkt *PacketBuffer) (ok bool) } // TransportDispatcher contains the methods used by the network stack to deliver @@ -313,6 +318,14 @@ type NetworkProtocol interface { // Wait waits for any worker goroutines owned by the protocol to stop. Wait() + + // Parse sets pkt.NetworkHeader and trims pkt.Data appropriately. It + // returns: + // - The encapsulated protocol, if present. + // - Whether there is an encapsulated transport protocol payload (e.g. ARP + // does not encapsulate anything). + // - Whether pkt.Data was large enough to parse and set pkt.NetworkHeader. + Parse(pkt *PacketBuffer) (proto tcpip.TransportProtocolNumber, hasTransportHdr bool, ok bool) } // NetworkDispatcher contains the methods used by the network stack to deliver diff --git a/pkg/tcpip/stack/stack_test.go b/pkg/tcpip/stack/stack_test.go index f6ddc3ced..ffef9bc2c 100644 --- a/pkg/tcpip/stack/stack_test.go +++ b/pkg/tcpip/stack/stack_test.go @@ -52,6 +52,10 @@ const ( // where another value is explicitly used. It is chosen to match the MTU // of loopback interfaces on linux systems. defaultMTU = 65536 + + dstAddrOffset = 0 + srcAddrOffset = 1 + protocolNumberOffset = 2 ) // fakeNetworkEndpoint is a network-layer protocol endpoint. It counts sent and @@ -94,26 +98,24 @@ func (f *fakeNetworkEndpoint) HandlePacket(r *stack.Route, pkt *stack.PacketBuff // Increment the received packet count in the protocol descriptor. f.proto.packetCount[int(f.id.LocalAddress[0])%len(f.proto.packetCount)]++ - // Consume the network header. - b, ok := pkt.Data.PullUp(fakeNetHeaderLen) - if !ok { - return - } - pkt.Data.TrimFront(fakeNetHeaderLen) - // Handle control packets. - if b[2] == uint8(fakeControlProtocol) { + if pkt.NetworkHeader[protocolNumberOffset] == uint8(fakeControlProtocol) { nb, ok := pkt.Data.PullUp(fakeNetHeaderLen) if !ok { return } pkt.Data.TrimFront(fakeNetHeaderLen) - f.dispatcher.DeliverTransportControlPacket(tcpip.Address(nb[1:2]), tcpip.Address(nb[0:1]), fakeNetNumber, tcpip.TransportProtocolNumber(nb[2]), stack.ControlPortUnreachable, 0, pkt) + f.dispatcher.DeliverTransportControlPacket( + tcpip.Address(nb[srcAddrOffset:srcAddrOffset+1]), + tcpip.Address(nb[dstAddrOffset:dstAddrOffset+1]), + fakeNetNumber, + tcpip.TransportProtocolNumber(nb[protocolNumberOffset]), + stack.ControlPortUnreachable, 0, pkt) return } // Dispatch the packet to the transport protocol. - f.dispatcher.DeliverTransportPacket(r, tcpip.TransportProtocolNumber(b[2]), pkt) + f.dispatcher.DeliverTransportPacket(r, tcpip.TransportProtocolNumber(pkt.NetworkHeader[protocolNumberOffset]), pkt) } func (f *fakeNetworkEndpoint) MaxHeaderLength() uint16 { @@ -138,18 +140,13 @@ func (f *fakeNetworkEndpoint) WritePacket(r *stack.Route, gso *stack.GSO, params // Add the protocol's header to the packet and send it to the link // endpoint. - b := pkt.Header.Prepend(fakeNetHeaderLen) - b[0] = r.RemoteAddress[0] - b[1] = f.id.LocalAddress[0] - b[2] = byte(params.Protocol) + pkt.NetworkHeader = pkt.Header.Prepend(fakeNetHeaderLen) + pkt.NetworkHeader[dstAddrOffset] = r.RemoteAddress[0] + pkt.NetworkHeader[srcAddrOffset] = f.id.LocalAddress[0] + pkt.NetworkHeader[protocolNumberOffset] = byte(params.Protocol) if r.Loop&stack.PacketLoop != 0 { - views := make([]buffer.View, 1, 1+len(pkt.Data.Views())) - views[0] = pkt.Header.View() - views = append(views, pkt.Data.Views()...) - f.HandlePacket(r, &stack.PacketBuffer{ - Data: buffer.NewVectorisedView(len(views[0])+pkt.Data.Size(), views), - }) + f.HandlePacket(r, pkt) } if r.Loop&stack.PacketOut == 0 { return nil @@ -205,7 +202,7 @@ func (f *fakeNetworkProtocol) PacketCount(intfAddr byte) int { } func (*fakeNetworkProtocol) ParseAddresses(v buffer.View) (src, dst tcpip.Address) { - return tcpip.Address(v[1:2]), tcpip.Address(v[0:1]) + return tcpip.Address(v[srcAddrOffset : srcAddrOffset+1]), tcpip.Address(v[dstAddrOffset : dstAddrOffset+1]) } func (f *fakeNetworkProtocol) NewEndpoint(nicID tcpip.NICID, addrWithPrefix tcpip.AddressWithPrefix, linkAddrCache stack.LinkAddressCache, dispatcher stack.TransportDispatcher, ep stack.LinkEndpoint, _ *stack.Stack) (stack.NetworkEndpoint, *tcpip.Error) { @@ -247,6 +244,17 @@ func (*fakeNetworkProtocol) Close() {} // Wait implements TransportProtocol.Wait. func (*fakeNetworkProtocol) Wait() {} +// Parse implements TransportProtocol.Parse. +func (*fakeNetworkProtocol) Parse(pkt *stack.PacketBuffer) (tcpip.TransportProtocolNumber, bool, bool) { + hdr, ok := pkt.Data.PullUp(fakeNetHeaderLen) + if !ok { + return 0, false, false + } + pkt.NetworkHeader = hdr + pkt.Data.TrimFront(fakeNetHeaderLen) + return tcpip.TransportProtocolNumber(hdr[protocolNumberOffset]), true, true +} + func fakeNetFactory() stack.NetworkProtocol { return &fakeNetworkProtocol{} } @@ -292,7 +300,7 @@ func TestNetworkReceive(t *testing.T) { buf := buffer.NewView(30) // Make sure packet with wrong address is not delivered. - buf[0] = 3 + buf[dstAddrOffset] = 3 ep.InjectInbound(fakeNetNumber, &stack.PacketBuffer{ Data: buf.ToVectorisedView(), }) @@ -304,7 +312,7 @@ func TestNetworkReceive(t *testing.T) { } // Make sure packet is delivered to first endpoint. - buf[0] = 1 + buf[dstAddrOffset] = 1 ep.InjectInbound(fakeNetNumber, &stack.PacketBuffer{ Data: buf.ToVectorisedView(), }) @@ -316,7 +324,7 @@ func TestNetworkReceive(t *testing.T) { } // Make sure packet is delivered to second endpoint. - buf[0] = 2 + buf[dstAddrOffset] = 2 ep.InjectInbound(fakeNetNumber, &stack.PacketBuffer{ Data: buf.ToVectorisedView(), }) @@ -982,7 +990,7 @@ func TestAddressRemoval(t *testing.T) { buf := buffer.NewView(30) // Send and receive packets, and verify they are received. - buf[0] = localAddrByte + buf[dstAddrOffset] = localAddrByte testRecv(t, fakeNet, localAddrByte, ep, buf) testSendTo(t, s, remoteAddr, ep, nil) @@ -1032,7 +1040,7 @@ func TestAddressRemovalWithRouteHeld(t *testing.T) { } // Send and receive packets, and verify they are received. - buf[0] = localAddrByte + buf[dstAddrOffset] = localAddrByte testRecv(t, fakeNet, localAddrByte, ep, buf) testSend(t, r, ep, nil) testSendTo(t, s, remoteAddr, ep, nil) @@ -1114,7 +1122,7 @@ func TestEndpointExpiration(t *testing.T) { fakeNet := s.NetworkProtocolInstance(fakeNetNumber).(*fakeNetworkProtocol) buf := buffer.NewView(30) - buf[0] = localAddrByte + buf[dstAddrOffset] = localAddrByte if promiscuous { if err := s.SetPromiscuousMode(nicID, true); err != nil { @@ -1277,7 +1285,7 @@ func TestPromiscuousMode(t *testing.T) { // Write a packet, and check that it doesn't get delivered as we don't // have a matching endpoint. const localAddrByte byte = 0x01 - buf[0] = localAddrByte + buf[dstAddrOffset] = localAddrByte testFailingRecv(t, fakeNet, localAddrByte, ep, buf) // Set promiscuous mode, then check that packet is delivered. @@ -1658,7 +1666,7 @@ func TestAddressRangeAcceptsMatchingPacket(t *testing.T) { buf := buffer.NewView(30) const localAddrByte byte = 0x01 - buf[0] = localAddrByte + buf[dstAddrOffset] = localAddrByte subnet, err := tcpip.NewSubnet(tcpip.Address("\x00"), tcpip.AddressMask("\xF0")) if err != nil { t.Fatal("NewSubnet failed:", err) @@ -1766,7 +1774,7 @@ func TestAddressRangeRejectsNonmatchingPacket(t *testing.T) { buf := buffer.NewView(30) const localAddrByte byte = 0x01 - buf[0] = localAddrByte + buf[dstAddrOffset] = localAddrByte subnet, err := tcpip.NewSubnet(tcpip.Address("\x10"), tcpip.AddressMask("\xF0")) if err != nil { t.Fatal("NewSubnet failed:", err) @@ -2344,7 +2352,7 @@ func TestNICForwarding(t *testing.T) { // Send a packet to dstAddr. buf := buffer.NewView(30) - buf[0] = dstAddr[0] + buf[dstAddrOffset] = dstAddr[0] ep1.InjectInbound(fakeNetNumber, &stack.PacketBuffer{ Data: buf.ToVectorisedView(), }) diff --git a/pkg/tcpip/stack/transport_test.go b/pkg/tcpip/stack/transport_test.go index cb350ead3..ad61c09d6 100644 --- a/pkg/tcpip/stack/transport_test.go +++ b/pkg/tcpip/stack/transport_test.go @@ -83,7 +83,8 @@ func (f *fakeTransportEndpoint) Write(p tcpip.Payloader, opts tcpip.WriteOptions return 0, nil, tcpip.ErrNoRoute } - hdr := buffer.NewPrependable(int(f.route.MaxHeaderLength())) + hdr := buffer.NewPrependable(int(f.route.MaxHeaderLength()) + fakeTransHeaderLen) + hdr.Prepend(fakeTransHeaderLen) v, err := p.FullPayload() if err != nil { return 0, nil, err @@ -324,6 +325,17 @@ func (*fakeTransportProtocol) Close() {} // Wait implements TransportProtocol.Wait. func (*fakeTransportProtocol) Wait() {} +// Parse implements TransportProtocol.Parse. +func (*fakeTransportProtocol) Parse(pkt *stack.PacketBuffer) bool { + hdr, ok := pkt.Data.PullUp(fakeTransHeaderLen) + if !ok { + return false + } + pkt.TransportHeader = hdr + pkt.Data.TrimFront(fakeTransHeaderLen) + return true +} + func fakeTransFactory() stack.TransportProtocol { return &fakeTransportProtocol{} } @@ -642,11 +654,10 @@ func TestTransportForwarding(t *testing.T) { t.Fatal("Response packet not forwarded") } - hdrs := p.Pkt.Data.ToView() - if dst := hdrs[0]; dst != 3 { + if dst := p.Pkt.NetworkHeader[0]; dst != 3 { t.Errorf("Response packet has incorrect destination addresss: got = %d, want = 3", dst) } - if src := hdrs[1]; src != 1 { + if src := p.Pkt.NetworkHeader[1]; src != 1 { t.Errorf("Response packet has incorrect source addresss: got = %d, want = 3", src) } } diff --git a/pkg/tcpip/transport/icmp/protocol.go b/pkg/tcpip/transport/icmp/protocol.go index 2ec6749c7..74ef6541e 100644 --- a/pkg/tcpip/transport/icmp/protocol.go +++ b/pkg/tcpip/transport/icmp/protocol.go @@ -124,6 +124,16 @@ func (*protocol) Close() {} // Wait implements stack.TransportProtocol.Wait. func (*protocol) Wait() {} +// Parse implements stack.TransportProtocol.Parse. +func (*protocol) Parse(pkt *stack.PacketBuffer) bool { + // TODO(gvisor.dev/issue/170): Implement parsing of ICMP. + // + // Right now, the Parse() method is tied to enabled protocols passed into + // stack.New. This works for UDP and TCP, but we handle ICMP traffic even + // when netstack users don't pass ICMP as a supported protocol. + return false +} + // NewProtocol4 returns an ICMPv4 transport protocol. func NewProtocol4() stack.TransportProtocol { return &protocol{ProtocolNumber4} diff --git a/pkg/tcpip/transport/raw/endpoint.go b/pkg/tcpip/transport/raw/endpoint.go index 21c34fac2..a406d815e 100644 --- a/pkg/tcpip/transport/raw/endpoint.go +++ b/pkg/tcpip/transport/raw/endpoint.go @@ -627,8 +627,9 @@ func (e *endpoint) HandlePacket(route *stack.Route, pkt *stack.PacketBuffer) { }, } - networkHeader := append(buffer.View(nil), pkt.NetworkHeader...) - combinedVV := networkHeader.ToVectorisedView() + headers := append(buffer.View(nil), pkt.NetworkHeader...) + headers = append(headers, pkt.TransportHeader...) + combinedVV := headers.ToVectorisedView() combinedVV.Append(pkt.Data) packet.data = combinedVV packet.timestampNS = e.stack.NowNanoseconds() diff --git a/pkg/tcpip/transport/tcp/protocol.go b/pkg/tcpip/transport/tcp/protocol.go index c827d0277..73b8a6782 100644 --- a/pkg/tcpip/transport/tcp/protocol.go +++ b/pkg/tcpip/transport/tcp/protocol.go @@ -21,6 +21,7 @@ package tcp import ( + "fmt" "runtime" "strings" "time" @@ -490,6 +491,26 @@ func (p *protocol) SynRcvdCounter() *synRcvdCounter { return &p.synRcvdCount } +// Parse implements stack.TransportProtocol.Parse. +func (*protocol) Parse(pkt *stack.PacketBuffer) bool { + hdr, ok := pkt.Data.PullUp(header.TCPMinimumSize) + if !ok { + return false + } + + // If the header has options, pull those up as well. + if offset := int(header.TCP(hdr).DataOffset()); offset > header.TCPMinimumSize && offset <= pkt.Data.Size() { + hdr, ok = pkt.Data.PullUp(offset) + if !ok { + panic(fmt.Sprintf("There should be at least %d bytes in pkt.Data.", offset)) + } + } + + pkt.TransportHeader = hdr + pkt.Data.TrimFront(len(hdr)) + return true +} + // NewProtocol returns a TCP transport protocol. func NewProtocol() stack.TransportProtocol { return &protocol{ diff --git a/pkg/tcpip/transport/tcp/segment.go b/pkg/tcpip/transport/tcp/segment.go index 0c099e2fd..0280892a8 100644 --- a/pkg/tcpip/transport/tcp/segment.go +++ b/pkg/tcpip/transport/tcp/segment.go @@ -35,6 +35,7 @@ type segment struct { id stack.TransportEndpointID `state:"manual"` route stack.Route `state:"manual"` data buffer.VectorisedView `state:".(buffer.VectorisedView)"` + hdr header.TCP // views is used as buffer for data when its length is large // enough to store a VectorisedView. views [8]buffer.View `state:"nosave"` @@ -67,6 +68,7 @@ func newSegment(r *stack.Route, id stack.TransportEndpointID, pkt *stack.PacketB route: r.Clone(), } s.data = pkt.Data.Clone(s.views[:]) + s.hdr = header.TCP(pkt.TransportHeader) s.rcvdTime = time.Now() return s } @@ -146,12 +148,6 @@ func (s *segment) logicalLen() seqnum.Size { // TCP checksum and stores the checksum and result of checksum verification in // the csum and csumValid fields of the segment. func (s *segment) parse() bool { - h, ok := s.data.PullUp(header.TCPMinimumSize) - if !ok { - return false - } - hdr := header.TCP(h) - // h is the header followed by the payload. We check that the offset to // the data respects the following constraints: // 1. That it's at least the minimum header size; if we don't do this @@ -162,16 +158,12 @@ func (s *segment) parse() bool { // N.B. The segment has already been validated as having at least the // minimum TCP size before reaching here, so it's safe to read the // fields. - offset := int(hdr.DataOffset()) - if offset < header.TCPMinimumSize { - return false - } - hdrWithOpts, ok := s.data.PullUp(offset) - if !ok { + offset := int(s.hdr.DataOffset()) + if offset < header.TCPMinimumSize || offset > len(s.hdr) { return false } - s.options = []byte(hdrWithOpts[header.TCPMinimumSize:]) + s.options = []byte(s.hdr[header.TCPMinimumSize:]) s.parsedOptions = header.ParseTCPOptions(s.options) // Query the link capabilities to decide if checksum validation is @@ -180,22 +172,19 @@ func (s *segment) parse() bool { if s.route.Capabilities()&stack.CapabilityRXChecksumOffload != 0 { s.csumValid = true verifyChecksum = false - s.data.TrimFront(offset) } if verifyChecksum { - hdr = header.TCP(hdrWithOpts) - s.csum = hdr.Checksum() - xsum := s.route.PseudoHeaderChecksum(ProtocolNumber, uint16(s.data.Size())) - xsum = hdr.CalculateChecksum(xsum) - s.data.TrimFront(offset) + s.csum = s.hdr.Checksum() + xsum := s.route.PseudoHeaderChecksum(ProtocolNumber, uint16(s.data.Size()+len(s.hdr))) + xsum = s.hdr.CalculateChecksum(xsum) xsum = header.ChecksumVV(s.data, xsum) s.csumValid = xsum == 0xffff } - s.sequenceNumber = seqnum.Value(hdr.SequenceNumber()) - s.ackNumber = seqnum.Value(hdr.AckNumber()) - s.flags = hdr.Flags() - s.window = seqnum.Size(hdr.WindowSize()) + s.sequenceNumber = seqnum.Value(s.hdr.SequenceNumber()) + s.ackNumber = seqnum.Value(s.hdr.AckNumber()) + s.flags = s.hdr.Flags() + s.window = seqnum.Size(s.hdr.WindowSize()) return true } diff --git a/pkg/tcpip/transport/udp/endpoint.go b/pkg/tcpip/transport/udp/endpoint.go index 663af8fec..8c7895713 100644 --- a/pkg/tcpip/transport/udp/endpoint.go +++ b/pkg/tcpip/transport/udp/endpoint.go @@ -1270,16 +1270,14 @@ func (e *endpoint) Readiness(mask waiter.EventMask) waiter.EventMask { // endpoint. func (e *endpoint) HandlePacket(r *stack.Route, id stack.TransportEndpointID, pkt *stack.PacketBuffer) { // Get the header then trim it from the view. - hdr, ok := pkt.Data.PullUp(header.UDPMinimumSize) - if !ok || int(header.UDP(hdr).Length()) > pkt.Data.Size() { + hdr := header.UDP(pkt.TransportHeader) + if int(hdr.Length()) > pkt.Data.Size()+header.UDPMinimumSize { // Malformed packet. e.stack.Stats().UDP.MalformedPacketsReceived.Increment() e.stats.ReceiveErrors.MalformedPacketsReceived.Increment() return } - pkt.Data.TrimFront(header.UDPMinimumSize) - e.rcvMu.Lock() e.stack.Stats().UDP.PacketsReceived.Increment() e.stats.PacketsReceived.Increment() diff --git a/pkg/tcpip/transport/udp/protocol.go b/pkg/tcpip/transport/udp/protocol.go index e320c5758..4218e7d03 100644 --- a/pkg/tcpip/transport/udp/protocol.go +++ b/pkg/tcpip/transport/udp/protocol.go @@ -67,14 +67,8 @@ func (*protocol) ParsePorts(v buffer.View) (src, dst uint16, err *tcpip.Error) { // HandleUnknownDestinationPacket handles packets targeted at this protocol but // that don't match any existing endpoint. func (p *protocol) HandleUnknownDestinationPacket(r *stack.Route, id stack.TransportEndpointID, pkt *stack.PacketBuffer) bool { - // Get the header then trim it from the view. - h, ok := pkt.Data.PullUp(header.UDPMinimumSize) - if !ok { - // Malformed packet. - r.Stack().Stats().UDP.MalformedPacketsReceived.Increment() - return true - } - if int(header.UDP(h).Length()) > pkt.Data.Size() { + hdr := header.UDP(pkt.TransportHeader) + if int(hdr.Length()) > pkt.Data.Size()+header.UDPMinimumSize { // Malformed packet. r.Stack().Stats().UDP.MalformedPacketsReceived.Increment() return true @@ -121,7 +115,7 @@ func (p *protocol) HandleUnknownDestinationPacket(r *stack.Route, id stack.Trans } headerLen := int(r.MaxHeaderLength()) + header.ICMPv4MinimumSize available := int(mtu) - headerLen - payloadLen := len(pkt.NetworkHeader) + pkt.Data.Size() + payloadLen := len(pkt.NetworkHeader) + len(pkt.TransportHeader) + pkt.Data.Size() if payloadLen > available { payloadLen = available } @@ -130,9 +124,10 @@ func (p *protocol) HandleUnknownDestinationPacket(r *stack.Route, id stack.Trans // For example, a raw or packet socket may use what UDP // considers an unreachable destination. Thus we deep copy pkt // to prevent multiple ownership and SR errors. - newNetHeader := append(buffer.View(nil), pkt.NetworkHeader...) - payload := newNetHeader.ToVectorisedView() - payload.Append(pkt.Data.ToView().ToVectorisedView()) + newHeader := append(buffer.View(nil), pkt.NetworkHeader...) + newHeader = append(newHeader, pkt.TransportHeader...) + payload := newHeader.ToVectorisedView() + payload.AppendView(pkt.Data.ToView()) payload.CapLength(payloadLen) hdr := buffer.NewPrependable(headerLen) @@ -141,8 +136,9 @@ func (p *protocol) HandleUnknownDestinationPacket(r *stack.Route, id stack.Trans pkt.SetCode(header.ICMPv4PortUnreachable) pkt.SetChecksum(header.ICMPv4Checksum(pkt, payload)) r.WritePacket(nil /* gso */, stack.NetworkHeaderParams{Protocol: header.ICMPv4ProtocolNumber, TTL: r.DefaultTTL(), TOS: stack.DefaultTOS}, &stack.PacketBuffer{ - Header: hdr, - Data: payload, + Header: hdr, + TransportHeader: buffer.View(pkt), + Data: payload, }) case header.IPv6AddressSize: @@ -164,11 +160,11 @@ func (p *protocol) HandleUnknownDestinationPacket(r *stack.Route, id stack.Trans } headerLen := int(r.MaxHeaderLength()) + header.ICMPv6DstUnreachableMinimumSize available := int(mtu) - headerLen - payloadLen := len(pkt.NetworkHeader) + pkt.Data.Size() + payloadLen := len(pkt.NetworkHeader) + len(pkt.TransportHeader) + pkt.Data.Size() if payloadLen > available { payloadLen = available } - payload := buffer.NewVectorisedView(len(pkt.NetworkHeader), []buffer.View{pkt.NetworkHeader}) + payload := buffer.NewVectorisedView(len(pkt.NetworkHeader)+len(pkt.TransportHeader), []buffer.View{pkt.NetworkHeader, pkt.TransportHeader}) payload.Append(pkt.Data) payload.CapLength(payloadLen) @@ -178,8 +174,9 @@ func (p *protocol) HandleUnknownDestinationPacket(r *stack.Route, id stack.Trans pkt.SetCode(header.ICMPv6PortUnreachable) pkt.SetChecksum(header.ICMPv6Checksum(pkt, r.LocalAddress, r.RemoteAddress, payload)) r.WritePacket(nil /* gso */, stack.NetworkHeaderParams{Protocol: header.ICMPv6ProtocolNumber, TTL: r.DefaultTTL(), TOS: stack.DefaultTOS}, &stack.PacketBuffer{ - Header: hdr, - Data: payload, + Header: hdr, + TransportHeader: buffer.View(pkt), + Data: payload, }) } return true @@ -201,6 +198,18 @@ func (*protocol) Close() {} // Wait implements stack.TransportProtocol.Wait. func (*protocol) Wait() {} +// Parse implements stack.TransportProtocol.Parse. +func (*protocol) Parse(pkt *stack.PacketBuffer) bool { + h, ok := pkt.Data.PullUp(header.UDPMinimumSize) + if !ok { + // Packet is too small + return false + } + pkt.TransportHeader = h + pkt.Data.TrimFront(header.UDPMinimumSize) + return true +} + // NewProtocol returns a UDP transport protocol. func NewProtocol() stack.TransportProtocol { return &protocol{} diff --git a/pkg/tcpip/transport/udp/udp_test.go b/pkg/tcpip/transport/udp/udp_test.go index e8ade882b..313a3f117 100644 --- a/pkg/tcpip/transport/udp/udp_test.go +++ b/pkg/tcpip/transport/udp/udp_test.go @@ -441,9 +441,7 @@ func (c *testContext) injectV6Packet(payload []byte, h *header4Tuple, valid bool // Inject packet. c.linkEP.InjectInbound(ipv6.ProtocolNumber, &stack.PacketBuffer{ - Data: buf.ToVectorisedView(), - NetworkHeader: buffer.View(ip), - TransportHeader: buffer.View(u), + Data: buf.ToVectorisedView(), }) } @@ -488,9 +486,7 @@ func (c *testContext) injectV4Packet(payload []byte, h *header4Tuple, valid bool // Inject packet. c.linkEP.InjectInbound(ipv4.ProtocolNumber, &stack.PacketBuffer{ - Data: buf.ToVectorisedView(), - NetworkHeader: buffer.View(ip), - TransportHeader: buffer.View(u), + Data: buf.ToVectorisedView(), }) } @@ -1720,6 +1716,58 @@ func TestIncrementMalformedPacketsReceived(t *testing.T) { } } +// TestShortHeader verifies that when a packet with a too-short UDP header is +// received, the malformed received global stat gets incremented. +func TestShortHeader(t *testing.T) { + c := newDualTestContext(t, defaultMTU) + defer c.cleanup() + + c.createEndpoint(ipv6.ProtocolNumber) + // Bind to wildcard. + if err := c.ep.Bind(tcpip.FullAddress{Port: stackPort}); err != nil { + c.t.Fatalf("Bind failed: %s", err) + } + + c.t.Helper() + h := unicastV6.header4Tuple(incoming) + + // Allocate a buffer for an IPv6 and too-short UDP header. + const udpSize = header.UDPMinimumSize - 1 + buf := buffer.NewView(header.IPv6MinimumSize + udpSize) + // Initialize the IP header. + ip := header.IPv6(buf) + ip.Encode(&header.IPv6Fields{ + TrafficClass: testTOS, + PayloadLength: uint16(udpSize), + NextHeader: uint8(udp.ProtocolNumber), + HopLimit: 65, + SrcAddr: h.srcAddr.Addr, + DstAddr: h.dstAddr.Addr, + }) + + // Initialize the UDP header. + udpHdr := header.UDP(buffer.NewView(header.UDPMinimumSize)) + udpHdr.Encode(&header.UDPFields{ + SrcPort: h.srcAddr.Port, + DstPort: h.dstAddr.Port, + Length: header.UDPMinimumSize, + }) + // Calculate the UDP pseudo-header checksum. + xsum := header.PseudoHeaderChecksum(udp.ProtocolNumber, h.srcAddr.Addr, h.dstAddr.Addr, uint16(len(udpHdr))) + udpHdr.SetChecksum(^udpHdr.CalculateChecksum(xsum)) + // Copy all but the last byte of the UDP header into the packet. + copy(buf[header.IPv6MinimumSize:], udpHdr) + + // Inject packet. + c.linkEP.InjectInbound(ipv6.ProtocolNumber, &stack.PacketBuffer{ + Data: buf.ToVectorisedView(), + }) + + if got, want := c.s.Stats().MalformedRcvdPackets.Value(), uint64(1); got != want { + t.Errorf("got c.s.Stats().MalformedRcvdPackets.Value() = %d, want = %d", got, want) + } +} + // TestShutdownRead verifies endpoint read shutdown and error // stats increment on packet receive. func TestShutdownRead(t *testing.T) { |