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-rw-r--r--pkg/tcpip/network/ipv4/icmp.go53
-rw-r--r--pkg/tcpip/network/ipv4/ipv4.go114
-rw-r--r--pkg/tcpip/network/ipv4/ipv4_test.go127
3 files changed, 241 insertions, 53 deletions
diff --git a/pkg/tcpip/network/ipv4/icmp.go b/pkg/tcpip/network/ipv4/icmp.go
index 2b7bc0dd0..b44304cee 100644
--- a/pkg/tcpip/network/ipv4/icmp.go
+++ b/pkg/tcpip/network/ipv4/icmp.go
@@ -213,7 +213,8 @@ func (e *endpoint) handleICMP(pkt *stack.PacketBuffer) {
} else {
op = &optionUsageReceive{}
}
- tmp, optProblem := e.processIPOptions(pkt, opts, op)
+ var optProblem *header.IPv4OptParameterProblem
+ newOptions, optProblem = e.processIPOptions(pkt, opts, op)
if optProblem != nil {
if optProblem.NeedICMP {
_ = e.protocol.returnError(&icmpReasonParamProblem{
@@ -224,7 +225,14 @@ func (e *endpoint) handleICMP(pkt *stack.PacketBuffer) {
}
return
}
- newOptions = tmp
+ copied := copy(opts, newOptions)
+ if copied != len(newOptions) {
+ panic(fmt.Sprintf("copied %d bytes of new options, expected %d bytes", copied, len(newOptions)))
+ }
+ for i := copied; i < len(opts); i++ {
+ // Pad with 0 (EOL). RFC 791 page 23 says "The padding is zero".
+ opts[i] = byte(header.IPv4OptionListEndType)
+ }
}
// TODO(b/112892170): Meaningfully handle all ICMP types.
@@ -375,6 +383,7 @@ func (e *endpoint) handleICMP(pkt *stack.PacketBuffer) {
// icmpReason is a marker interface for IPv4 specific ICMP errors.
type icmpReason interface {
isICMPReason()
+ isForwarding() bool
}
// icmpReasonPortUnreachable is an error where the transport protocol has no
@@ -382,12 +391,18 @@ type icmpReason interface {
type icmpReasonPortUnreachable struct{}
func (*icmpReasonPortUnreachable) isICMPReason() {}
+func (*icmpReasonPortUnreachable) isForwarding() bool {
+ return false
+}
// icmpReasonProtoUnreachable is an error where the transport protocol is
// not supported.
type icmpReasonProtoUnreachable struct{}
func (*icmpReasonProtoUnreachable) isICMPReason() {}
+func (*icmpReasonProtoUnreachable) isForwarding() bool {
+ return false
+}
// icmpReasonTTLExceeded is an error where a packet's time to live exceeded in
// transit to its final destination, as per RFC 792 page 6, Time Exceeded
@@ -395,6 +410,15 @@ func (*icmpReasonProtoUnreachable) isICMPReason() {}
type icmpReasonTTLExceeded struct{}
func (*icmpReasonTTLExceeded) isICMPReason() {}
+func (*icmpReasonTTLExceeded) isForwarding() bool {
+ // If we hit a TTL Exceeded error, then we know we are operating as a router.
+ // As per RFC 792 page 6, Time Exceeded Message,
+ //
+ // If the gateway processing a datagram finds the time to live field
+ // is zero it must discard the datagram. The gateway may also notify
+ // the source host via the time exceeded message.
+ return true
+}
// icmpReasonReassemblyTimeout is an error where insufficient fragments are
// received to complete reassembly of a packet within a configured time after
@@ -402,14 +426,21 @@ func (*icmpReasonTTLExceeded) isICMPReason() {}
type icmpReasonReassemblyTimeout struct{}
func (*icmpReasonReassemblyTimeout) isICMPReason() {}
+func (*icmpReasonReassemblyTimeout) isForwarding() bool {
+ return false
+}
// icmpReasonParamProblem is an error to use to request a Parameter Problem
// message to be sent.
type icmpReasonParamProblem struct {
- pointer byte
+ pointer byte
+ forwarding bool
}
func (*icmpReasonParamProblem) isICMPReason() {}
+func (r *icmpReasonParamProblem) isForwarding() bool {
+ return r.forwarding
+}
// returnError takes an error descriptor and generates the appropriate ICMP
// error packet for IPv4 and sends it back to the remote device that sent
@@ -448,26 +479,14 @@ func (p *protocol) returnError(reason icmpReason, pkt *stack.PacketBuffer) tcpip
return nil
}
- // If we hit a TTL Exceeded error, then we know we are operating as a router.
- // As per RFC 792 page 6, Time Exceeded Message,
- //
- // If the gateway processing a datagram finds the time to live field
- // is zero it must discard the datagram. The gateway may also notify
- // the source host via the time exceeded message.
- //
- // ...
- //
- // Code 0 may be received from a gateway. ...
- //
- // Note, Code 0 is the TTL exceeded error.
- //
// If we are operating as a router/gateway, don't use the packet's destination
// address as the response's source address as we should not not own the
// destination address of a packet we are forwarding.
localAddr := origIPHdrDst
- if _, ok := reason.(*icmpReasonTTLExceeded); ok {
+ if reason.isForwarding() {
localAddr = ""
}
+
// Even if we were able to receive a packet from some remote, we may not have
// a route to it - the remote may be blocked via routing rules. We must always
// consult our routing table and find a route to the remote before sending any
diff --git a/pkg/tcpip/network/ipv4/ipv4.go b/pkg/tcpip/network/ipv4/ipv4.go
index 7de438fe3..c5e4034ce 100644
--- a/pkg/tcpip/network/ipv4/ipv4.go
+++ b/pkg/tcpip/network/ipv4/ipv4.go
@@ -561,6 +561,34 @@ func (e *endpoint) forwardPacket(pkt *stack.PacketBuffer) tcpip.Error {
return e.protocol.returnError(&icmpReasonTTLExceeded{}, pkt)
}
+ if opts := h.Options(); len(opts) != 0 {
+ newOpts, optProblem := e.processIPOptions(pkt, opts, &optionUsageForward{})
+ if optProblem != nil {
+ if optProblem.NeedICMP {
+ _ = e.protocol.returnError(&icmpReasonParamProblem{
+ pointer: optProblem.Pointer,
+ forwarding: true,
+ }, pkt)
+ e.protocol.stack.Stats().MalformedRcvdPackets.Increment()
+ e.stats.ip.MalformedPacketsReceived.Increment()
+ }
+ return nil // option problems are not reported locally.
+ }
+ copied := copy(opts, newOpts)
+ if copied != len(newOpts) {
+ panic(fmt.Sprintf("copied %d bytes of new options, expected %d bytes", copied, len(newOpts)))
+ }
+ // Since in forwarding we handle all options, including copying those we
+ // do not recognise, the options region should remain the same size which
+ // simplifies processing. As we MAY receive a packet with a lot of padded
+ // bytes after the "end of options list" byte, make sure we copy
+ // them as the legal padding value (0).
+ for i := copied; i < len(opts); i++ {
+ // Pad with 0 (EOL). RFC 791 page 23 says "The padding is zero".
+ opts[i] = byte(header.IPv4OptionListEndType)
+ }
+ }
+
dstAddr := h.DestinationAddress()
// Check if the destination is owned by the stack.
@@ -711,8 +739,9 @@ func (e *endpoint) handlePacket(pkt *stack.PacketBuffer) {
}
}
- // The destination address should be an address we own or a group we joined
- // for us to receive the packet. Otherwise, attempt to forward the packet.
+ // Before we do any processing, note if the packet was received as some
+ // sort of broadcast. The destination address should be an address we own
+ // or a group we joined.
if addressEndpoint := e.AcquireAssignedAddress(dstAddr, e.nic.Promiscuous(), stack.CanBePrimaryEndpoint); addressEndpoint != nil {
subnet := addressEndpoint.AddressWithPrefix().Subnet()
addressEndpoint.DecRef()
@@ -722,7 +751,6 @@ func (e *endpoint) handlePacket(pkt *stack.PacketBuffer) {
stats.ip.InvalidDestinationAddressesReceived.Increment()
return
}
-
_ = e.forwardPacket(pkt)
return
}
@@ -744,6 +772,21 @@ func (e *endpoint) handlePacket(pkt *stack.PacketBuffer) {
stats.ip.MalformedFragmentsReceived.Increment()
return
}
+ if opts := h.Options(); len(opts) != 0 {
+ // If there are options we need to check them before we do assembly
+ // or we could be assembling errant packets. However we do not change the
+ // options as that could lead to double processing later.
+ if _, optProblem := e.processIPOptions(pkt, opts, &optionUsageVerify{}); optProblem != nil {
+ if optProblem.NeedICMP {
+ _ = e.protocol.returnError(&icmpReasonParamProblem{
+ pointer: optProblem.Pointer,
+ }, pkt)
+ e.protocol.stack.Stats().MalformedRcvdPackets.Increment()
+ e.stats.ip.MalformedPacketsReceived.Increment()
+ }
+ return
+ }
+ }
// The packet is a fragment, let's try to reassemble it.
start := h.FragmentOffset()
// Drop the fragment if the size of the reassembled payload would exceed the
@@ -802,17 +845,10 @@ func (e *endpoint) handlePacket(pkt *stack.PacketBuffer) {
e.handleICMP(pkt)
return
}
- if p == header.IGMPProtocolNumber {
- e.mu.Lock()
- e.mu.igmp.handleIGMP(pkt)
- e.mu.Unlock()
- return
- }
+ // ICMP handles options itself but do it here for all remaining destinations.
if opts := h.Options(); len(opts) != 0 {
- // TODO(gvisor.dev/issue/4586):
- // When we add forwarding support we should use the verified options
- // rather than just throwing them away.
- if _, optProblem := e.processIPOptions(pkt, opts, &optionUsageReceive{}); optProblem != nil {
+ newOpts, optProblem := e.processIPOptions(pkt, opts, &optionUsageReceive{})
+ if optProblem != nil {
if optProblem.NeedICMP {
_ = e.protocol.returnError(&icmpReasonParamProblem{
pointer: optProblem.Pointer,
@@ -822,6 +858,20 @@ func (e *endpoint) handlePacket(pkt *stack.PacketBuffer) {
}
return
}
+ copied := copy(opts, newOpts)
+ if copied != len(newOpts) {
+ panic(fmt.Sprintf("copied %d bytes of new options, expected %d bytes", copied, len(newOpts)))
+ }
+ for i := copied; i < len(opts); i++ {
+ // Pad with 0 (EOL). RFC 791 page 23 says "The padding is zero".
+ opts[i] = byte(header.IPv4OptionListEndType)
+ }
+ }
+ if p == header.IGMPProtocolNumber {
+ e.mu.Lock()
+ e.mu.igmp.handleIGMP(pkt)
+ e.mu.Unlock()
+ return
}
switch res := e.dispatcher.DeliverTransportPacket(p, pkt); res {
@@ -1254,23 +1304,49 @@ type optionsUsage interface {
actions() optionActions
}
-// optionUsageReceive implements optionsUsage for received packets.
-type optionUsageReceive struct{}
+// optionUsageVerify implements optionsUsage for when we just want to check
+// fragments. Don't change anything, just check and reject if bad. No
+// replacement options are generated.
+type optionUsageVerify struct{}
// actions implements optionsUsage.
-func (*optionUsageReceive) actions() optionActions {
+func (*optionUsageVerify) actions() optionActions {
return optionActions{
timestamp: optionVerify,
recordRoute: optionVerify,
+ unknown: optionRemove,
+ }
+}
+
+// optionUsageReceive implements optionsUsage for packets we will pass
+// to the transport layer (with the exception of Echo requests).
+type optionUsageReceive struct{}
+
+// actions implements optionsUsage.
+func (*optionUsageReceive) actions() optionActions {
+ return optionActions{
+ timestamp: optionProcess,
+ recordRoute: optionProcess,
unknown: optionPass,
}
}
-// TODO(gvisor.dev/issue/4586): Add an entry here for forwarding when it
-// is enabled (Process, Process, Pass) and for fragmenting (Process, Process,
-// Pass for frag1, but Remove,Remove,Remove for all other frags).
+// optionUsageForward implements optionsUsage for packets about to be forwarded.
+// All options are passed on regardless of whether we recognise them, however
+// we do process the Timestamp and Record Route options.
+type optionUsageForward struct{}
+
+// actions implements optionsUsage.
+func (*optionUsageForward) actions() optionActions {
+ return optionActions{
+ timestamp: optionProcess,
+ recordRoute: optionProcess,
+ unknown: optionPass,
+ }
+}
// optionUsageEcho implements optionsUsage for echo packet processing.
+// Only Timestamp and RecordRoute are processed and sent back.
type optionUsageEcho struct{}
// actions implements optionsUsage.
diff --git a/pkg/tcpip/network/ipv4/ipv4_test.go b/pkg/tcpip/network/ipv4/ipv4_test.go
index a296bed79..c57d7f616 100644
--- a/pkg/tcpip/network/ipv4/ipv4_test.go
+++ b/pkg/tcpip/network/ipv4/ipv4_test.go
@@ -111,10 +111,11 @@ func TestExcludeBroadcast(t *testing.T) {
func TestForwarding(t *testing.T) {
const (
- nicID1 = 1
- nicID2 = 2
- randomSequence = 123
- randomIdent = 42
+ nicID1 = 1
+ nicID2 = 2
+ randomSequence = 123
+ randomIdent = 42
+ randomTimeOffset = 0x10203040
)
ipv4Addr1 := tcpip.AddressWithPrefix{
@@ -129,14 +130,20 @@ func TestForwarding(t *testing.T) {
remoteIPv4Addr2 := tcpip.Address(net.ParseIP("11.0.0.2").To4())
tests := []struct {
- name string
- TTL uint8
- expectErrorICMP bool
+ name string
+ TTL uint8
+ expectErrorICMP bool
+ options header.IPv4Options
+ forwardedOptions header.IPv4Options
+ icmpType header.ICMPv4Type
+ icmpCode header.ICMPv4Code
}{
{
name: "TTL of zero",
TTL: 0,
expectErrorICMP: true,
+ icmpType: header.ICMPv4TimeExceeded,
+ icmpCode: header.ICMPv4TTLExceeded,
},
{
name: "TTL of one",
@@ -153,14 +160,78 @@ func TestForwarding(t *testing.T) {
TTL: math.MaxUint8,
expectErrorICMP: false,
},
+ {
+ name: "four EOL options",
+ TTL: 2,
+ expectErrorICMP: false,
+ options: header.IPv4Options{0, 0, 0, 0},
+ forwardedOptions: header.IPv4Options{0, 0, 0, 0},
+ },
+ {
+ name: "TS type 1 full",
+ TTL: 2,
+ options: header.IPv4Options{
+ 68, 12, 13, 0xF1,
+ 192, 168, 1, 12,
+ 1, 2, 3, 4,
+ },
+ expectErrorICMP: true,
+ icmpType: header.ICMPv4ParamProblem,
+ icmpCode: header.ICMPv4UnusedCode,
+ },
+ {
+ name: "TS type 0",
+ TTL: 2,
+ options: header.IPv4Options{
+ 68, 24, 21, 0x00,
+ 1, 2, 3, 4,
+ 5, 6, 7, 8,
+ 9, 10, 11, 12,
+ 13, 14, 15, 16,
+ 0, 0, 0, 0,
+ },
+ forwardedOptions: header.IPv4Options{
+ 68, 24, 25, 0x00,
+ 1, 2, 3, 4,
+ 5, 6, 7, 8,
+ 9, 10, 11, 12,
+ 13, 14, 15, 16,
+ 0x00, 0xad, 0x1c, 0x40, // time we expect from fakeclock
+ },
+ },
+ {
+ name: "end of options list",
+ TTL: 2,
+ options: header.IPv4Options{
+ 68, 12, 13, 0x11,
+ 192, 168, 1, 12,
+ 1, 2, 3, 4,
+ 0, 10, 3, 99, // EOL followed by junk
+ 1, 2, 3, 4,
+ },
+ forwardedOptions: header.IPv4Options{
+ 68, 12, 13, 0x21,
+ 192, 168, 1, 12,
+ 1, 2, 3, 4,
+ 0, // End of Options hides following bytes.
+ 0, 0, 0, // 7 bytes unknown option removed.
+ 0, 0, 0, 0,
+ },
+ },
}
-
for _, test := range tests {
t.Run(test.name, func(t *testing.T) {
+ clock := faketime.NewManualClock()
s := stack.New(stack.Options{
NetworkProtocols: []stack.NetworkProtocolFactory{ipv4.NewProtocol},
TransportProtocols: []stack.TransportProtocolFactory{icmp.NewProtocol4},
+ Clock: clock,
})
+
+ // Advance the clock by some unimportant amount to make
+ // it give a more recognisable signature than 00,00,00,00.
+ clock.Advance(time.Millisecond * randomTimeOffset)
+
// We expect at most a single packet in response to our ICMP Echo Request.
e1 := channel.New(1, ipv4.MaxTotalSize, "")
if err := s.CreateNIC(nicID1, e1); err != nil {
@@ -195,7 +266,11 @@ func TestForwarding(t *testing.T) {
t.Fatalf("SetForwarding(%d, true): %s", header.IPv4ProtocolNumber, err)
}
- totalLen := uint16(header.IPv4MinimumSize + header.ICMPv4MinimumSize)
+ ipHeaderLength := header.IPv4MinimumSize + len(test.options)
+ if ipHeaderLength > header.IPv4MaximumHeaderSize {
+ t.Fatalf("got ipHeaderLength = %d, want <= %d ", ipHeaderLength, header.IPv4MaximumHeaderSize)
+ }
+ totalLen := uint16(ipHeaderLength + header.ICMPv4MinimumSize)
hdr := buffer.NewPrependable(int(totalLen))
icmp := header.ICMPv4(hdr.Prepend(header.ICMPv4MinimumSize))
icmp.SetIdent(randomIdent)
@@ -204,7 +279,7 @@ func TestForwarding(t *testing.T) {
icmp.SetCode(header.ICMPv4UnusedCode)
icmp.SetChecksum(0)
icmp.SetChecksum(^header.Checksum(icmp, 0))
- ip := header.IPv4(hdr.Prepend(header.IPv4MinimumSize))
+ ip := header.IPv4(hdr.Prepend(ipHeaderLength))
ip.Encode(&header.IPv4Fields{
TotalLength: totalLen,
Protocol: uint8(header.ICMPv4ProtocolNumber),
@@ -212,6 +287,14 @@ func TestForwarding(t *testing.T) {
SrcAddr: remoteIPv4Addr1,
DstAddr: remoteIPv4Addr2,
})
+ if len(test.options) != 0 {
+ ip.SetHeaderLength(uint8(ipHeaderLength))
+ // Copy options manually. We do not use Encode for options so we can
+ // verify malformed options with handcrafted payloads.
+ if want, got := copy(ip.Options(), test.options), len(test.options); want != got {
+ t.Fatalf("got copy(ip.Options(), test.options) = %d, want = %d", got, want)
+ }
+ }
ip.SetChecksum(0)
ip.SetChecksum(^ip.CalculateChecksum())
requestPkt := stack.NewPacketBuffer(stack.PacketBufferOptions{
@@ -222,7 +305,7 @@ func TestForwarding(t *testing.T) {
if test.expectErrorICMP {
reply, ok := e1.Read()
if !ok {
- t.Fatal("expected ICMP TTL Exceeded packet through incoming NIC")
+ t.Fatalf("expected ICMP packet type %d through incoming NIC", test.icmpType)
}
checker.IPv4(t, header.IPv4(stack.PayloadSince(reply.Pkt.NetworkHeader())),
@@ -231,8 +314,8 @@ func TestForwarding(t *testing.T) {
checker.TTL(ipv4.DefaultTTL),
checker.ICMPv4(
checker.ICMPv4Checksum(),
- checker.ICMPv4Type(header.ICMPv4TimeExceeded),
- checker.ICMPv4Code(header.ICMPv4TTLExceeded),
+ checker.ICMPv4Type(test.icmpType),
+ checker.ICMPv4Code(test.icmpCode),
checker.ICMPv4Payload([]byte(hdr.View())),
),
)
@@ -250,6 +333,7 @@ func TestForwarding(t *testing.T) {
checker.SrcAddr(remoteIPv4Addr1),
checker.DstAddr(remoteIPv4Addr2),
checker.TTL(test.TTL-1),
+ checker.IPv4Options(test.forwardedOptions),
checker.ICMPv4(
checker.ICMPv4Checksum(),
checker.ICMPv4Type(header.ICMPv4Echo),
@@ -279,6 +363,7 @@ func TestIPv4Sanity(t *testing.T) {
// (offset 1). For compatibility we must do the same. Use this constant
// to indicate where this happens.
pointerOffsetForInvalidLength = 0
+ randomTimeOffset = 0x10203040
)
var (
ipv4Addr = tcpip.AddressWithPrefix{
@@ -893,6 +978,10 @@ func TestIPv4Sanity(t *testing.T) {
TransportProtocols: []stack.TransportProtocolFactory{icmp.NewProtocol4},
Clock: clock,
})
+ // Advance the clock by some unimportant amount to make
+ // it give a more recognisable signature than 00,00,00,00.
+ clock.Advance(time.Millisecond * randomTimeOffset)
+
// We expect at most a single packet in response to our ICMP Echo Request.
e := channel.New(1, ipv4.MaxTotalSize, "")
if err := s.CreateNIC(nicID, e); err != nil {
@@ -902,9 +991,6 @@ func TestIPv4Sanity(t *testing.T) {
if err := s.AddProtocolAddress(nicID, ipv4ProtoAddr); err != nil {
t.Fatalf("AddProtocolAddress(%d, %#v): %s", nicID, ipv4ProtoAddr, err)
}
- // Advance the clock by some unimportant amount to make
- // sure it's all set up.
- clock.Advance(time.Millisecond * 0x10203040)
// Default routes for IPv4 so ICMP can find a route to the remote
// node when attempting to send the ICMP Echo Reply.
@@ -1739,12 +1825,19 @@ func TestInvalidFragments(t *testing.T) {
ip := header.IPv4(hdr.Prepend(pktSize))
ip.Encode(&f.ipv4fields)
+ if want, got := len(f.payload), copy(ip[header.IPv4MinimumSize:], f.payload); want != got {
+ t.Fatalf("copied %d bytes, expected %d bytes.", got, want)
+ }
// Encode sets this up correctly. If we want a different value for
// testing then we need to overwrite the good value.
if f.overrideIHL != 0 {
ip.SetHeaderLength(uint8(f.overrideIHL))
+ // If we are asked to add options (type not specified) then pad
+ // with 0 (EOL). RFC 791 page 23 says "The padding is zero".
+ for i := header.IPv4MinimumSize; i < f.overrideIHL; i++ {
+ ip[i] = byte(header.IPv4OptionListEndType)
+ }
}
- copy(ip[header.IPv4MinimumSize:], f.payload)
if f.autoChecksum {
ip.SetChecksum(0)
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-15 12:32:53 +0000