diff options
author | Ghanan Gowripalan <ghanan@google.com> | 2020-04-02 18:29:09 -0700 |
---|---|---|
committer | gVisor bot <gvisor-bot@google.com> | 2020-04-02 18:30:15 -0700 |
commit | 4582a2f188953d34591aef1a479d19d9be8f640f (patch) | |
tree | f25d748a9cbee2e50ed9485e5425c2ccefce66c4 /pkg | |
parent | 5b2396d244ed6283d928a72bdd4cc58d78ef3175 (diff) |
Drop NDP messages with fragment extension header
As per RFC 6980 section 5, nodes MUST silently ignore NDP messages if
the packet carrying them include an IPv6 Fragmentation Header.
Test: ipv6_test.TestNDPValidation
PiperOrigin-RevId: 304519379
Diffstat (limited to 'pkg')
-rw-r--r-- | pkg/tcpip/header/ipv6_extension_headers.go | 4 | ||||
-rw-r--r-- | pkg/tcpip/network/ipv6/icmp.go | 7 | ||||
-rw-r--r-- | pkg/tcpip/network/ipv6/ipv6.go | 5 | ||||
-rw-r--r-- | pkg/tcpip/network/ipv6/ndp_test.go | 157 |
4 files changed, 108 insertions, 65 deletions
diff --git a/pkg/tcpip/header/ipv6_extension_headers.go b/pkg/tcpip/header/ipv6_extension_headers.go index 1b6c3f328..82485ed6a 100644 --- a/pkg/tcpip/header/ipv6_extension_headers.go +++ b/pkg/tcpip/header/ipv6_extension_headers.go @@ -62,6 +62,10 @@ const ( // within an IPv6RoutingExtHdr. ipv6RoutingExtHdrSegmentsLeftIdx = 1 + // IPv6FragmentExtHdrLength is the length of an IPv6 extension header, in + // bytes. + IPv6FragmentExtHdrLength = 8 + // ipv6FragmentExtHdrFragmentOffsetOffset is the offset to the start of the // Fragment Offset field within an IPv6FragmentExtHdr. ipv6FragmentExtHdrFragmentOffsetOffset = 0 diff --git a/pkg/tcpip/network/ipv6/icmp.go b/pkg/tcpip/network/ipv6/icmp.go index 81e6f4d67..6d2d2c034 100644 --- a/pkg/tcpip/network/ipv6/icmp.go +++ b/pkg/tcpip/network/ipv6/icmp.go @@ -62,7 +62,7 @@ func (e *endpoint) handleControl(typ stack.ControlType, extra uint32, pkt stack. e.dispatcher.DeliverTransportControlPacket(e.id.LocalAddress, h.DestinationAddress(), ProtocolNumber, p, typ, extra, pkt) } -func (e *endpoint) handleICMP(r *stack.Route, netHeader buffer.View, pkt stack.PacketBuffer) { +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 @@ -91,7 +91,10 @@ func (e *endpoint) handleICMP(r *stack.Route, netHeader buffer.View, pkt stack.P // 8.1, nodes MUST silently drop NDP packets where the Hop Limit field // in the IPv6 header is not set to 255, or the ICMPv6 Code field is not // set to 0. - return iph.HopLimit() == header.NDPHopLimit && h.Code() == 0 + // + // As per RFC 6980 section 5, nodes MUST silently drop NDP messages if the + // packet includes a fragmentation header. + return !hasFragmentHeader && iph.HopLimit() == header.NDPHopLimit && h.Code() == 0 } // TODO(b/112892170): Meaningfully handle all ICMP types. diff --git a/pkg/tcpip/network/ipv6/ipv6.go b/pkg/tcpip/network/ipv6/ipv6.go index 685239017..b462b8604 100644 --- a/pkg/tcpip/network/ipv6/ipv6.go +++ b/pkg/tcpip/network/ipv6/ipv6.go @@ -185,6 +185,7 @@ func (e *endpoint) HandlePacket(r *stack.Route, pkt stack.PacketBuffer) { pkt.Data.CapLength(int(h.PayloadLength())) it := header.MakeIPv6PayloadIterator(header.IPv6ExtensionHeaderIdentifier(h.NextHeader()), pkt.Data) + hasFragmentHeader := false for firstHeader := true; ; firstHeader = false { extHdr, done, err := it.Next() @@ -257,6 +258,8 @@ 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 { @@ -344,7 +347,7 @@ func (e *endpoint) HandlePacket(r *stack.Route, pkt stack.PacketBuffer) { pkt.Data = extHdr.Buf if p := tcpip.TransportProtocolNumber(extHdr.Identifier); p == header.ICMPv6ProtocolNumber { - e.handleICMP(r, headerView, pkt) + e.handleICMP(r, headerView, pkt, hasFragmentHeader) } else { r.Stats().IP.PacketsDelivered.Increment() // TODO(b/152019344): Send an ICMPv6 Parameter Problem, Code 1 error diff --git a/pkg/tcpip/network/ipv6/ndp_test.go b/pkg/tcpip/network/ipv6/ndp_test.go index 3b05e8062..b113aaacc 100644 --- a/pkg/tcpip/network/ipv6/ndp_test.go +++ b/pkg/tcpip/network/ipv6/ndp_test.go @@ -276,9 +276,7 @@ func TestNeighorAdvertisementWithTargetLinkLayerOption(t *testing.T) { } } -// TestHopLimitValidation is a test that makes sure that NDP packets are only -// received if their IP header's hop limit is set to 255. -func TestHopLimitValidation(t *testing.T) { +func TestNDPValidation(t *testing.T) { setup := func(t *testing.T) (*stack.Stack, stack.NetworkEndpoint, stack.Route) { t.Helper() @@ -294,12 +292,19 @@ func TestHopLimitValidation(t *testing.T) { return s, ep, r } - handleIPv6Payload := func(hdr buffer.Prependable, hopLimit uint8, ep stack.NetworkEndpoint, r *stack.Route) { + handleIPv6Payload := func(hdr buffer.Prependable, hopLimit uint8, atomicFragment bool, ep stack.NetworkEndpoint, r *stack.Route) { + nextHdr := uint8(header.ICMPv6ProtocolNumber) + if atomicFragment { + bytes := hdr.Prepend(header.IPv6FragmentExtHdrLength) + bytes[0] = nextHdr + nextHdr = uint8(header.IPv6FragmentExtHdrIdentifier) + } + payloadLength := hdr.UsedLength() ip := header.IPv6(hdr.Prepend(header.IPv6MinimumSize)) ip.Encode(&header.IPv6Fields{ PayloadLength: uint16(payloadLength), - NextHeader: uint8(header.ICMPv6ProtocolNumber), + NextHeader: nextHdr, HopLimit: hopLimit, SrcAddr: r.LocalAddress, DstAddr: r.RemoteAddress, @@ -364,65 +369,93 @@ func TestHopLimitValidation(t *testing.T) { }, } + subTests := []struct { + name string + atomicFragment bool + hopLimit uint8 + code uint8 + valid bool + }{ + { + name: "Valid", + atomicFragment: false, + hopLimit: header.NDPHopLimit, + code: 0, + valid: true, + }, + { + name: "Fragmented", + atomicFragment: true, + hopLimit: header.NDPHopLimit, + code: 0, + valid: false, + }, + { + name: "Invalid hop limit", + atomicFragment: false, + hopLimit: header.NDPHopLimit - 1, + code: 0, + valid: false, + }, + { + name: "Invalid ICMPv6 code", + atomicFragment: false, + hopLimit: header.NDPHopLimit, + code: 1, + valid: false, + }, + } + for _, typ := range types { t.Run(typ.name, func(t *testing.T) { - s, ep, r := setup(t) - defer r.Release() - - stats := s.Stats().ICMP.V6PacketsReceived - invalid := stats.Invalid - typStat := typ.statCounter(stats) - - 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())) - - // Rx count of the NDP message should initially be 0. - if got := typStat.Value(); got != 0 { - t.Errorf("got %s = %d, want = 0", typ.name, got) - } - - // Invalid count should initially be 0. - if got := invalid.Value(); got != 0 { - t.Errorf("got invalid = %d, want = 0", got) - } - - if t.Failed() { - t.FailNow() - } - - // Receive the NDP packet with an invalid hop limit. - handleIPv6Payload(hdr, header.NDPHopLimit-1, ep, &r) - - // Rx count of the NDP packet should have increased. - if got := typStat.Value(); got != 1 { - t.Errorf("got %s = %d, want = 1", typ.name, got) - } - - // Invalid count should have increased. - if got := invalid.Value(); got != 1 { - t.Errorf("got invalid = %d, want = 1", got) - } - - if t.Failed() { - t.FailNow() - } - - // Receive the NDP packet with a valid hop limit value. - handleIPv6Payload(hdr, header.NDPHopLimit, ep, &r) - - // Rx count of the NDP packet should have increased. - if got := typStat.Value(); got != 2 { - t.Errorf("got %s = %d, want = 2", typ.name, got) - } - - // Invalid count should not have increased again. - if got := invalid.Value(); got != 1 { - t.Errorf("got invalid = %d, want = 1", got) + for _, test := range subTests { + t.Run(test.name, func(t *testing.T) { + s, ep, r := setup(t) + defer r.Release() + + stats := s.Stats().ICMP.V6PacketsReceived + 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())) + + // Rx count of the NDP message should initially be 0. + if got := typStat.Value(); got != 0 { + t.Errorf("got %s = %d, want = 0", typ.name, got) + } + + // Invalid count should initially be 0. + if got := invalid.Value(); got != 0 { + t.Errorf("got invalid = %d, want = 0", got) + } + + if t.Failed() { + t.FailNow() + } + + handleIPv6Payload(hdr, test.hopLimit, test.atomicFragment, ep, &r) + + // Rx count of the NDP packet should have increased. + if got := typStat.Value(); got != 1 { + t.Errorf("got %s = %d, want = 1", typ.name, got) + } + + want := uint64(0) + if !test.valid { + // Invalid count should have increased. + want = 1 + } + if got := invalid.Value(); got != want { + t.Errorf("got invalid = %d, want = %d", got, want) + } + }) } }) } |