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-rw-r--r--pkg/tcpip/network/ipv6/icmp.go51
-rw-r--r--pkg/tcpip/network/ipv6/icmp_test.go4
-rw-r--r--pkg/tcpip/network/ipv6/ndp_test.go189
-rw-r--r--pkg/tcpip/stack/ndp.go55
-rw-r--r--pkg/tcpip/stack/nic.go13
-rw-r--r--pkg/tcpip/stack/stack.go16
6 files changed, 322 insertions, 6 deletions
diff --git a/pkg/tcpip/network/ipv6/icmp.go b/pkg/tcpip/network/ipv6/icmp.go
index c3f1dd488..05e8c075b 100644
--- a/pkg/tcpip/network/ipv6/icmp.go
+++ b/pkg/tcpip/network/ipv6/icmp.go
@@ -86,7 +86,8 @@ func (e *endpoint) handleICMP(r *stack.Route, netHeader buffer.View, vv buffer.V
// As per RFC 4861 sections 4.1 - 4.5, 6.1.1, 6.1.2, 7.1.1, 7.1.2 and
// 8.1, nodes MUST silently drop NDP packets where the Hop Limit field
- // in the IPv6 header is not set to 255.
+ // in the IPv6 header is not set to 255, or the ICMPv6 Code field is not
+ // set to 0.
switch h.Type() {
case header.ICMPv6NeighborSolicit,
header.ICMPv6NeighborAdvert,
@@ -97,6 +98,11 @@ func (e *endpoint) handleICMP(r *stack.Route, netHeader buffer.View, vv buffer.V
received.Invalid.Increment()
return
}
+
+ if h.Code() != 0 {
+ received.Invalid.Increment()
+ return
+ }
}
// TODO(b/112892170): Meaningfully handle all ICMP types.
@@ -309,8 +315,51 @@ func (e *endpoint) handleICMP(r *stack.Route, netHeader buffer.View, vv buffer.V
received.RouterSolicit.Increment()
case header.ICMPv6RouterAdvert:
+ routerAddr := iph.SourceAddress()
+
+ //
+ // Validate the RA as per RFC 4861 section 6.1.2.
+ //
+
+ // Is the IP Source Address a link-local address?
+ if !header.IsV6LinkLocalAddress(routerAddr) {
+ // ...No, silently drop the packet.
+ received.Invalid.Increment()
+ return
+ }
+
+ p := h.NDPPayload()
+
+ // Is the NDP payload of sufficient size to hold a Router
+ // Advertisement?
+ if len(p) < header.NDPRAMinimumSize {
+ // ...No, silently drop the packet.
+ received.Invalid.Increment()
+ return
+ }
+
+ ra := header.NDPRouterAdvert(p)
+ opts := ra.Options()
+
+ // Are options valid as per the wire format?
+ if _, err := opts.Iter(true); err != nil {
+ // ...No, silently drop the packet.
+ received.Invalid.Increment()
+ return
+ }
+
+ //
+ // At this point, we have a valid Router Advertisement, as far
+ // as RFC 4861 section 6.1.2 is concerned.
+ //
+
received.RouterAdvert.Increment()
+ // Tell the NIC to handle the RA.
+ stack := r.Stack()
+ rxNICID := r.NICID()
+ stack.HandleNDPRA(rxNICID, routerAddr, ra)
+
case header.ICMPv6RedirectMsg:
received.RedirectMsg.Increment()
diff --git a/pkg/tcpip/network/ipv6/icmp_test.go b/pkg/tcpip/network/ipv6/icmp_test.go
index b112303b6..d686f79ce 100644
--- a/pkg/tcpip/network/ipv6/icmp_test.go
+++ b/pkg/tcpip/network/ipv6/icmp_test.go
@@ -131,7 +131,7 @@ func TestICMPCounts(t *testing.T) {
{header.ICMPv6EchoRequest, header.ICMPv6EchoMinimumSize},
{header.ICMPv6EchoReply, header.ICMPv6EchoMinimumSize},
{header.ICMPv6RouterSolicit, header.ICMPv6MinimumSize},
- {header.ICMPv6RouterAdvert, header.ICMPv6MinimumSize},
+ {header.ICMPv6RouterAdvert, header.ICMPv6HeaderSize + header.NDPRAMinimumSize},
{header.ICMPv6NeighborSolicit, header.ICMPv6NeighborSolicitMinimumSize},
{header.ICMPv6NeighborAdvert, header.ICMPv6NeighborAdvertSize},
{header.ICMPv6RedirectMsg, header.ICMPv6MinimumSize},
@@ -426,7 +426,7 @@ func TestICMPChecksumValidationSimple(t *testing.T) {
{
"RouterAdvert",
header.ICMPv6RouterAdvert,
- header.ICMPv6MinimumSize,
+ header.ICMPv6HeaderSize + header.NDPRAMinimumSize,
func(stats tcpip.ICMPv6ReceivedPacketStats) *tcpip.StatCounter {
return stats.RouterAdvert
},
diff --git a/pkg/tcpip/network/ipv6/ndp_test.go b/pkg/tcpip/network/ipv6/ndp_test.go
index c32716f2e..69ab7ba12 100644
--- a/pkg/tcpip/network/ipv6/ndp_test.go
+++ b/pkg/tcpip/network/ipv6/ndp_test.go
@@ -21,6 +21,7 @@ import (
"gvisor.dev/gvisor/pkg/tcpip"
"gvisor.dev/gvisor/pkg/tcpip/buffer"
"gvisor.dev/gvisor/pkg/tcpip/header"
+ "gvisor.dev/gvisor/pkg/tcpip/link/channel"
"gvisor.dev/gvisor/pkg/tcpip/stack"
"gvisor.dev/gvisor/pkg/tcpip/transport/icmp"
)
@@ -109,7 +110,7 @@ func TestHopLimitValidation(t *testing.T) {
{"RouterSolicit", header.ICMPv6RouterSolicit, header.ICMPv6MinimumSize, func(stats tcpip.ICMPv6ReceivedPacketStats) *tcpip.StatCounter {
return stats.RouterSolicit
}},
- {"RouterAdvert", header.ICMPv6RouterAdvert, header.ICMPv6MinimumSize, func(stats tcpip.ICMPv6ReceivedPacketStats) *tcpip.StatCounter {
+ {"RouterAdvert", header.ICMPv6RouterAdvert, header.ICMPv6HeaderSize + header.NDPRAMinimumSize, func(stats tcpip.ICMPv6ReceivedPacketStats) *tcpip.StatCounter {
return stats.RouterAdvert
}},
{"NeighborSolicit", header.ICMPv6NeighborSolicit, header.ICMPv6NeighborSolicitMinimumSize, func(stats tcpip.ICMPv6ReceivedPacketStats) *tcpip.StatCounter {
@@ -179,3 +180,189 @@ func TestHopLimitValidation(t *testing.T) {
})
}
}
+
+// TestRouterAdvertValidation tests that when the NIC is configured to handle
+// NDP Router Advertisement packets, it validates the Router Advertisement
+// properly before handling them.
+func TestRouterAdvertValidation(t *testing.T) {
+ tests := []struct {
+ name string
+ src tcpip.Address
+ hopLimit uint8
+ code uint8
+ ndpPayload []byte
+ expectedSuccess bool
+ }{
+ {
+ "OK",
+ lladdr0,
+ 255,
+ 0,
+ []byte{
+ 0, 0, 0, 0,
+ 0, 0, 0, 0,
+ 0, 0, 0, 0,
+ },
+ true,
+ },
+ {
+ "NonLinkLocalSourceAddr",
+ addr1,
+ 255,
+ 0,
+ []byte{
+ 0, 0, 0, 0,
+ 0, 0, 0, 0,
+ 0, 0, 0, 0,
+ },
+ false,
+ },
+ {
+ "HopLimitNot255",
+ lladdr0,
+ 254,
+ 0,
+ []byte{
+ 0, 0, 0, 0,
+ 0, 0, 0, 0,
+ 0, 0, 0, 0,
+ },
+ false,
+ },
+ {
+ "NonZeroCode",
+ lladdr0,
+ 255,
+ 1,
+ []byte{
+ 0, 0, 0, 0,
+ 0, 0, 0, 0,
+ 0, 0, 0, 0,
+ },
+ false,
+ },
+ {
+ "NDPPayloadTooSmall",
+ lladdr0,
+ 255,
+ 0,
+ []byte{
+ 0, 0, 0, 0,
+ 0, 0, 0, 0,
+ 0, 0, 0,
+ },
+ false,
+ },
+ {
+ "OKWithOptions",
+ lladdr0,
+ 255,
+ 0,
+ []byte{
+ // RA payload
+ 0, 0, 0, 0,
+ 0, 0, 0, 0,
+ 0, 0, 0, 0,
+
+ // Option #1 (TargetLinkLayerAddress)
+ 2, 1, 0, 0, 0, 0, 0, 0,
+
+ // Option #2 (unrecognized)
+ 255, 1, 0, 0, 0, 0, 0, 0,
+
+ // Option #3 (PrefixInformation)
+ 3, 4, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0,
+ },
+ true,
+ },
+ {
+ "OptionWithZeroLength",
+ lladdr0,
+ 255,
+ 0,
+ []byte{
+ // RA payload
+ 0, 0, 0, 0,
+ 0, 0, 0, 0,
+ 0, 0, 0, 0,
+
+ // Option #1 (TargetLinkLayerAddress)
+ // Invalid as it has 0 length.
+ 2, 0, 0, 0, 0, 0, 0, 0,
+
+ // Option #2 (unrecognized)
+ 255, 1, 0, 0, 0, 0, 0, 0,
+
+ // Option #3 (PrefixInformation)
+ 3, 4, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0,
+ },
+ false,
+ },
+ }
+
+ for _, test := range tests {
+ t.Run(test.name, func(t *testing.T) {
+ e := channel.New(10, 1280, linkAddr1)
+ s := stack.New(stack.Options{
+ NetworkProtocols: []stack.NetworkProtocol{NewProtocol()},
+ })
+
+ if err := s.CreateNIC(1, e); err != nil {
+ t.Fatalf("CreateNIC(_) = %s", err)
+ }
+
+ icmpSize := header.ICMPv6HeaderSize + len(test.ndpPayload)
+ hdr := buffer.NewPrependable(header.IPv6MinimumSize + icmpSize)
+ pkt := header.ICMPv6(hdr.Prepend(icmpSize))
+ pkt.SetType(header.ICMPv6RouterAdvert)
+ pkt.SetCode(test.code)
+ copy(pkt.NDPPayload(), test.ndpPayload)
+ payloadLength := hdr.UsedLength()
+ pkt.SetChecksum(header.ICMPv6Checksum(pkt, test.src, header.IPv6AllNodesMulticastAddress, buffer.VectorisedView{}))
+ ip := header.IPv6(hdr.Prepend(header.IPv6MinimumSize))
+ ip.Encode(&header.IPv6Fields{
+ PayloadLength: uint16(payloadLength),
+ NextHeader: uint8(icmp.ProtocolNumber6),
+ HopLimit: test.hopLimit,
+ SrcAddr: test.src,
+ DstAddr: header.IPv6AllNodesMulticastAddress,
+ })
+
+ stats := s.Stats().ICMP.V6PacketsReceived
+ invalid := stats.Invalid
+ rxRA := stats.RouterAdvert
+
+ if got := invalid.Value(); got != 0 {
+ t.Fatalf("got invalid = %d, want = 0", got)
+ }
+ if got := rxRA.Value(); got != 0 {
+ t.Fatalf("got rxRA = %d, want = 0", got)
+ }
+
+ e.Inject(header.IPv6ProtocolNumber, hdr.View().ToVectorisedView())
+
+ if test.expectedSuccess {
+ if got := invalid.Value(); got != 0 {
+ t.Fatalf("got invalid = %d, want = 0", got)
+ }
+ if got := rxRA.Value(); got != 1 {
+ t.Fatalf("got rxRA = %d, want = 1", got)
+ }
+
+ } else {
+ if got := invalid.Value(); got != 1 {
+ t.Fatalf("got invalid = %d, want = 1", got)
+ }
+ if got := rxRA.Value(); got != 0 {
+ t.Fatalf("got rxRA = %d, want = 0", got)
+ }
+ }
+ })
+ }
+}
diff --git a/pkg/tcpip/stack/ndp.go b/pkg/tcpip/stack/ndp.go
index 03ddebdbd..d5352bb5f 100644
--- a/pkg/tcpip/stack/ndp.go
+++ b/pkg/tcpip/stack/ndp.go
@@ -38,6 +38,19 @@ const (
// Default = 1s (from RFC 4861 section 10).
defaultRetransmitTimer = time.Second
+ // defaultHandleRAs is the default configuration for whether or not to
+ // handle incoming Router Advertisements as a host.
+ //
+ // Default = true.
+ defaultHandleRAs = true
+
+ // defaultDiscoverDefaultRouters is the default configuration for
+ // whether or not to discover default routers from incoming Router
+ // Advertisements as a host.
+ //
+ // Default = true.
+ defaultDiscoverDefaultRouters = true
+
// minimumRetransmitTimer is the minimum amount of time to wait between
// sending NDP Neighbor solicitation messages. Note, RFC 4861 does
// not impose a minimum Retransmit Timer, but we do here to make sure
@@ -49,6 +62,13 @@ const (
//
// Min = 1ms.
minimumRetransmitTimer = time.Millisecond
+
+ // MaxDiscoveredDefaultRouters is the maximum number of discovered
+ // default routers. The stack should stop discovering new routers after
+ // discovering MaxDiscoveredDefaultRouters routers.
+ //
+ // Max = 10.
+ MaxDiscoveredDefaultRouters = 10
)
// NDPDispatcher is the interface integrators of netstack must implement to
@@ -80,6 +100,15 @@ type NDPConfigurations struct {
//
// Must be greater than 0.5s.
RetransmitTimer time.Duration
+
+ // HandleRAs determines whether or not Router Advertisements will be
+ // processed.
+ HandleRAs bool
+
+ // DiscoverDefaultRouters determines whether or not default routers will
+ // be discovered from Router Advertisements. This configuration is
+ // ignored if HandleRAs is false.
+ DiscoverDefaultRouters bool
}
// DefaultNDPConfigurations returns an NDPConfigurations populated with
@@ -88,6 +117,8 @@ func DefaultNDPConfigurations() NDPConfigurations {
return NDPConfigurations{
DupAddrDetectTransmits: defaultDupAddrDetectTransmits,
RetransmitTimer: defaultRetransmitTimer,
+ HandleRAs: defaultHandleRAs,
+ DiscoverDefaultRouters: defaultDiscoverDefaultRouters,
}
}
@@ -112,6 +143,9 @@ type ndpState struct {
// The DAD state to send the next NS message, or resolve the address.
dad map[tcpip.Address]dadState
+
+ // The default routers discovered through Router Advertisements.
+ defaultRouters map[tcpip.Address]defaultRouterState
}
// dadState holds the Duplicate Address Detection timer and channel to signal
@@ -127,6 +161,12 @@ type dadState struct {
done *bool
}
+// defaultRouterState holds data associated with a default router discovered by
+// a Router Advertisement.
+type defaultRouterState struct {
+ invalidationTimer *time.Timer
+}
+
// startDuplicateAddressDetection performs Duplicate Address Detection.
//
// This function must only be called by IPv6 addresses that are currently
@@ -319,3 +359,18 @@ func (ndp *ndpState) stopDuplicateAddressDetection(addr tcpip.Address) {
go ndp.nic.stack.ndpDisp.OnDuplicateAddressDetectionStatus(ndp.nic.ID(), addr, false, nil)
}
}
+
+// handleRA handles a Router Advertisement message that arrived on the NIC
+// this ndp is for.
+//
+// The NIC that ndp belongs to MUST be locked.
+func (ndp *ndpState) handleRA(ip tcpip.Address, ra header.NDPRouterAdvert) {
+ // Is the NIC configured to handle RAs at all?
+ if !ndp.configs.HandleRAs {
+ return
+ }
+
+ // TODO(b/140882146): Do Router Discovery.
+ // TODO(b/140948104): Do Prefix Discovery.
+ // TODO(b/141556115): Do Parameter Discovery.
+}
diff --git a/pkg/tcpip/stack/nic.go b/pkg/tcpip/stack/nic.go
index fe8f83d58..12969c74e 100644
--- a/pkg/tcpip/stack/nic.go
+++ b/pkg/tcpip/stack/nic.go
@@ -115,8 +115,9 @@ func newNIC(stack *Stack, id tcpip.NICID, name string, ep LinkEndpoint, loopback
},
},
ndp: ndpState{
- configs: stack.ndpConfigs,
- dad: make(map[tcpip.Address]dadState),
+ configs: stack.ndpConfigs,
+ dad: make(map[tcpip.Address]dadState),
+ defaultRouters: make(map[tcpip.Address]defaultRouterState),
},
}
nic.ndp.nic = nic
@@ -960,6 +961,14 @@ func (n *NIC) setNDPConfigs(c NDPConfigurations) {
n.mu.Unlock()
}
+// handleNDPRA handles an NDP Router Advertisement message that arrived on n.
+func (n *NIC) handleNDPRA(ip tcpip.Address, ra header.NDPRouterAdvert) {
+ n.mu.Lock()
+ defer n.mu.Unlock()
+
+ n.ndp.handleRA(ip, ra)
+}
+
type networkEndpointKind int32
const (
diff --git a/pkg/tcpip/stack/stack.go b/pkg/tcpip/stack/stack.go
index 115a6fcb8..8b141cafd 100644
--- a/pkg/tcpip/stack/stack.go
+++ b/pkg/tcpip/stack/stack.go
@@ -1557,6 +1557,22 @@ func (s *Stack) SetNDPConfigurations(id tcpip.NICID, c NDPConfigurations) *tcpip
return nil
}
+// HandleNDPRA provides a NIC with ID id a validated NDP Router Advertisement
+// message that it needs to handle.
+func (s *Stack) HandleNDPRA(id tcpip.NICID, ip tcpip.Address, ra header.NDPRouterAdvert) *tcpip.Error {
+ s.mu.Lock()
+ defer s.mu.Unlock()
+
+ nic, ok := s.nics[id]
+ if !ok {
+ return tcpip.ErrUnknownNICID
+ }
+
+ nic.handleNDPRA(ip, ra)
+
+ return nil
+}
+
// PortSeed returns a 32 bit value that can be used as a seed value for port
// picking.
//
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-25 16:58:27 +0000