diff options
Diffstat (limited to 'pkg/tcpip/network/ipv6/icmp.go')
| -rw-r--r-- | pkg/tcpip/network/ipv6/icmp.go | 74 |
1 files changed, 48 insertions, 26 deletions
diff --git a/pkg/tcpip/network/ipv6/icmp.go b/pkg/tcpip/network/ipv6/icmp.go index b68983d10..bdf3a0d25 100644 --- a/pkg/tcpip/network/ipv6/icmp.go +++ b/pkg/tcpip/network/ipv6/icmp.go @@ -28,7 +28,11 @@ import ( // used to find out which transport endpoint must be notified about the ICMP // packet. func (e *endpoint) handleControl(typ stack.ControlType, extra uint32, pkt stack.PacketBuffer) { - h := header.IPv6(pkt.Data.First()) + h, ok := pkt.Data.PullUp(header.IPv6MinimumSize) + if !ok { + return + } + hdr := header.IPv6(h) // We don't use IsValid() here because ICMP only requires that up to // 1280 bytes of the original packet be included. So it's likely that it @@ -36,17 +40,21 @@ func (e *endpoint) handleControl(typ stack.ControlType, extra uint32, pkt stack. // // Drop packet if it doesn't have the basic IPv6 header or if the // original source address doesn't match the endpoint's address. - if len(h) < header.IPv6MinimumSize || h.SourceAddress() != e.id.LocalAddress { + if hdr.SourceAddress() != e.id.LocalAddress { return } // Skip the IP header, then handle the fragmentation header if there // is one. pkt.Data.TrimFront(header.IPv6MinimumSize) - p := h.TransportProtocol() + p := hdr.TransportProtocol() if p == header.IPv6FragmentHeader { - f := header.IPv6Fragment(pkt.Data.First()) - if !f.IsValid() || f.FragmentOffset() != 0 { + f, ok := pkt.Data.PullUp(header.IPv6FragmentHeaderSize) + if !ok { + return + } + fragHdr := header.IPv6Fragment(f) + if !fragHdr.IsValid() || fragHdr.FragmentOffset() != 0 { // We can't handle fragments that aren't at offset 0 // because they don't have the transport headers. return @@ -55,19 +63,19 @@ func (e *endpoint) handleControl(typ stack.ControlType, extra uint32, pkt stack. // Skip fragmentation header and find out the actual protocol // number. pkt.Data.TrimFront(header.IPv6FragmentHeaderSize) - p = f.TransportProtocol() + p = fragHdr.TransportProtocol() } // Deliver the control packet to the transport endpoint. - e.dispatcher.DeliverTransportControlPacket(e.id.LocalAddress, h.DestinationAddress(), ProtocolNumber, p, typ, extra, pkt) + 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) { stats := r.Stats().ICMP sent := stats.V6PacketsSent received := stats.V6PacketsReceived - v := pkt.Data.First() - if len(v) < header.ICMPv6MinimumSize { + v, ok := pkt.Data.PullUp(header.ICMPv6HeaderSize) + if !ok { received.Invalid.Increment() return } @@ -76,11 +84,9 @@ func (e *endpoint) handleICMP(r *stack.Route, netHeader buffer.View, pkt stack.P // Validate ICMPv6 checksum before processing the packet. // - // Only the first view in vv is accounted for by h. To account for the - // rest of vv, a shallow copy is made and the first view is removed. // This copy is used as extra payload during the checksum calculation. payload := pkt.Data.Clone(nil) - payload.RemoveFirst() + payload.TrimFront(len(h)) if got, want := h.Checksum(), header.ICMPv6Checksum(h, iph.SourceAddress(), iph.DestinationAddress(), payload); got != want { received.Invalid.Increment() return @@ -101,34 +107,40 @@ func (e *endpoint) handleICMP(r *stack.Route, netHeader buffer.View, pkt stack.P switch h.Type() { case header.ICMPv6PacketTooBig: received.PacketTooBig.Increment() - if len(v) < header.ICMPv6PacketTooBigMinimumSize { + hdr, ok := pkt.Data.PullUp(header.ICMPv6PacketTooBigMinimumSize) + if !ok { received.Invalid.Increment() return } pkt.Data.TrimFront(header.ICMPv6PacketTooBigMinimumSize) - mtu := h.MTU() + mtu := header.ICMPv6(hdr).MTU() e.handleControl(stack.ControlPacketTooBig, calculateMTU(mtu), pkt) case header.ICMPv6DstUnreachable: received.DstUnreachable.Increment() - if len(v) < header.ICMPv6DstUnreachableMinimumSize { + hdr, ok := pkt.Data.PullUp(header.ICMPv6DstUnreachableMinimumSize) + if !ok { received.Invalid.Increment() return } pkt.Data.TrimFront(header.ICMPv6DstUnreachableMinimumSize) - switch h.Code() { + switch header.ICMPv6(hdr).Code() { case header.ICMPv6PortUnreachable: e.handleControl(stack.ControlPortUnreachable, 0, pkt) } case header.ICMPv6NeighborSolicit: received.NeighborSolicit.Increment() - if len(v) < header.ICMPv6NeighborSolicitMinimumSize || !isNDPValid() { + if pkt.Data.Size() < header.ICMPv6NeighborSolicitMinimumSize || !isNDPValid() { received.Invalid.Increment() return } - ns := header.NDPNeighborSolicit(h.NDPPayload()) + // The remainder of payload must be only the neighbor solicitation, so + // payload.ToView() always returns the solicitation. Per RFC 6980 section 5, + // NDP messages cannot be fragmented. Also note that in the common case NDP + // datagrams are very small and ToView() will not incur allocations. + ns := header.NDPNeighborSolicit(payload.ToView()) it, err := ns.Options().Iter(true) if err != nil { // If we have a malformed NDP NS option, drop the packet. @@ -286,12 +298,16 @@ func (e *endpoint) handleICMP(r *stack.Route, netHeader buffer.View, pkt stack.P case header.ICMPv6NeighborAdvert: received.NeighborAdvert.Increment() - if len(v) < header.ICMPv6NeighborAdvertSize || !isNDPValid() { + if pkt.Data.Size() < header.ICMPv6NeighborAdvertSize || !isNDPValid() { received.Invalid.Increment() return } - na := header.NDPNeighborAdvert(h.NDPPayload()) + // The remainder of payload must be only the neighbor advertisement, so + // payload.ToView() always returns the advertisement. Per RFC 6980 section + // 5, NDP messages cannot be fragmented. Also note that in the common case + // NDP datagrams are very small and ToView() will not incur allocations. + na := header.NDPNeighborAdvert(payload.ToView()) it, err := na.Options().Iter(true) if err != nil { // If we have a malformed NDP NA option, drop the packet. @@ -363,14 +379,15 @@ func (e *endpoint) handleICMP(r *stack.Route, netHeader buffer.View, pkt stack.P case header.ICMPv6EchoRequest: received.EchoRequest.Increment() - if len(v) < header.ICMPv6EchoMinimumSize { + icmpHdr, ok := pkt.Data.PullUp(header.ICMPv6EchoMinimumSize) + if !ok { received.Invalid.Increment() return } pkt.Data.TrimFront(header.ICMPv6EchoMinimumSize) hdr := buffer.NewPrependable(int(r.MaxHeaderLength()) + header.ICMPv6EchoMinimumSize) packet := header.ICMPv6(hdr.Prepend(header.ICMPv6EchoMinimumSize)) - copy(packet, h) + copy(packet, icmpHdr) packet.SetType(header.ICMPv6EchoReply) packet.SetChecksum(header.ICMPv6Checksum(packet, r.LocalAddress, r.RemoteAddress, pkt.Data)) if err := r.WritePacket(nil /* gso */, stack.NetworkHeaderParams{Protocol: header.ICMPv6ProtocolNumber, TTL: r.DefaultTTL(), TOS: stack.DefaultTOS}, stack.PacketBuffer{ @@ -384,7 +401,7 @@ func (e *endpoint) handleICMP(r *stack.Route, netHeader buffer.View, pkt stack.P case header.ICMPv6EchoReply: received.EchoReply.Increment() - if len(v) < header.ICMPv6EchoMinimumSize { + if pkt.Data.Size() < header.ICMPv6EchoMinimumSize { received.Invalid.Increment() return } @@ -406,8 +423,9 @@ func (e *endpoint) handleICMP(r *stack.Route, netHeader buffer.View, pkt stack.P case header.ICMPv6RouterAdvert: received.RouterAdvert.Increment() - p := h.NDPPayload() - if len(p) < header.NDPRAMinimumSize || !isNDPValid() { + // Is the NDP payload of sufficient size to hold a Router + // Advertisement? + if pkt.Data.Size()-header.ICMPv6HeaderSize < header.NDPRAMinimumSize || !isNDPValid() { received.Invalid.Increment() return } @@ -425,7 +443,11 @@ func (e *endpoint) handleICMP(r *stack.Route, netHeader buffer.View, pkt stack.P return } - ra := header.NDPRouterAdvert(p) + // The remainder of payload must be only the router advertisement, so + // payload.ToView() always returns the advertisement. Per RFC 6980 section + // 5, NDP messages cannot be fragmented. Also note that in the common case + // NDP datagrams are very small and ToView() will not incur allocations. + ra := header.NDPRouterAdvert(payload.ToView()) opts := ra.Options() // Are options valid as per the wire format? |