diff options
Diffstat (limited to 'pkg')
28 files changed, 458 insertions, 149 deletions
diff --git a/pkg/sentry/socket/netfilter/tcp_matcher.go b/pkg/sentry/socket/netfilter/tcp_matcher.go index ff1cfd8f6..55c0f04f3 100644 --- a/pkg/sentry/socket/netfilter/tcp_matcher.go +++ b/pkg/sentry/socket/netfilter/tcp_matcher.go @@ -121,12 +121,13 @@ func (tm *TCPMatcher) Match(hook stack.Hook, pkt stack.PacketBuffer, interfaceNa tcpHeader = header.TCP(pkt.TransportHeader) } else { // The TCP header hasn't been parsed yet. We have to do it here. - if len(pkt.Data.First()) < header.TCPMinimumSize { + hdr, ok := pkt.Data.PullUp(header.TCPMinimumSize) + if !ok { // There's no valid TCP header here, so we hotdrop the // packet. return false, true } - tcpHeader = header.TCP(pkt.Data.First()) + tcpHeader = header.TCP(hdr) } // 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 3359418c1..04d03d494 100644 --- a/pkg/sentry/socket/netfilter/udp_matcher.go +++ b/pkg/sentry/socket/netfilter/udp_matcher.go @@ -120,12 +120,13 @@ func (um *UDPMatcher) Match(hook stack.Hook, pkt stack.PacketBuffer, interfaceNa udpHeader = header.UDP(pkt.TransportHeader) } else { // The UDP header hasn't been parsed yet. We have to do it here. - if len(pkt.Data.First()) < header.UDPMinimumSize { + hdr, ok := pkt.Data.PullUp(header.UDPMinimumSize) + if !ok { // There's no valid UDP header here, so we hotdrop the // packet. return false, true } - udpHeader = header.UDP(pkt.Data.First()) + udpHeader = header.UDP(hdr) } // Check whether the source and destination ports are within the diff --git a/pkg/tcpip/buffer/view.go b/pkg/tcpip/buffer/view.go index 8ec5d5d5c..f01217c91 100644 --- a/pkg/tcpip/buffer/view.go +++ b/pkg/tcpip/buffer/view.go @@ -77,7 +77,8 @@ func NewVectorisedView(size int, views []View) VectorisedView { return VectorisedView{views: views, size: size} } -// TrimFront removes the first "count" bytes of the vectorised view. +// TrimFront removes the first "count" bytes of the vectorised view. It panics +// if count > vv.Size(). func (vv *VectorisedView) TrimFront(count int) { for count > 0 && len(vv.views) > 0 { if count < len(vv.views[0]) { @@ -86,7 +87,7 @@ func (vv *VectorisedView) TrimFront(count int) { return } count -= len(vv.views[0]) - vv.RemoveFirst() + vv.removeFirst() } } @@ -104,7 +105,7 @@ func (vv *VectorisedView) Read(v View) (copied int, err error) { count -= len(vv.views[0]) copy(v[copied:], vv.views[0]) copied += len(vv.views[0]) - vv.RemoveFirst() + vv.removeFirst() } if copied == 0 { return 0, io.EOF @@ -126,7 +127,7 @@ func (vv *VectorisedView) ReadToVV(dstVV *VectorisedView, count int) (copied int count -= len(vv.views[0]) dstVV.AppendView(vv.views[0]) copied += len(vv.views[0]) - vv.RemoveFirst() + vv.removeFirst() } return copied } @@ -162,22 +163,37 @@ func (vv *VectorisedView) Clone(buffer []View) VectorisedView { return VectorisedView{views: append(buffer[:0], vv.views...), size: vv.size} } -// First returns the first view of the vectorised view. -func (vv *VectorisedView) First() View { +// PullUp returns the first "count" bytes of the vectorised view. If those +// bytes aren't already contiguous inside the vectorised view, PullUp will +// reallocate as needed to make them contiguous. PullUp fails and returns false +// when count > vv.Size(). +func (vv *VectorisedView) PullUp(count int) (View, bool) { if len(vv.views) == 0 { - return nil + return nil, count == 0 + } + if count <= len(vv.views[0]) { + return vv.views[0][:count], true + } + if count > vv.size { + return nil, false } - return vv.views[0] -} -// RemoveFirst removes the first view of the vectorised view. -func (vv *VectorisedView) RemoveFirst() { - if len(vv.views) == 0 { - return + newFirst := NewView(count) + i := 0 + for offset := 0; offset < count; i++ { + copy(newFirst[offset:], vv.views[i]) + if count-offset < len(vv.views[i]) { + vv.views[i].TrimFront(count - offset) + break + } + offset += len(vv.views[i]) + vv.views[i] = nil } - vv.size -= len(vv.views[0]) - vv.views[0] = nil - vv.views = vv.views[1:] + // We're guaranteed that i > 0, since count is too large for the first + // view. + vv.views[i-1] = newFirst + vv.views = vv.views[i-1:] + return newFirst, true } // Size returns the size in bytes of the entire content stored in the vectorised view. @@ -225,3 +241,10 @@ func (vv *VectorisedView) Readers() []bytes.Reader { } return readers } + +// removeFirst panics when len(vv.views) < 1. +func (vv *VectorisedView) removeFirst() { + vv.size -= len(vv.views[0]) + vv.views[0] = nil + vv.views = vv.views[1:] +} diff --git a/pkg/tcpip/buffer/view_test.go b/pkg/tcpip/buffer/view_test.go index 106e1994c..c56795c7b 100644 --- a/pkg/tcpip/buffer/view_test.go +++ b/pkg/tcpip/buffer/view_test.go @@ -16,6 +16,7 @@ package buffer import ( + "bytes" "reflect" "testing" ) @@ -370,3 +371,115 @@ func TestVVRead(t *testing.T) { }) } } + +var pullUpTestCases = []struct { + comment string + in VectorisedView + count int + want []byte + result VectorisedView + ok bool +}{ + { + comment: "simple case", + in: vv(2, "12"), + count: 1, + want: []byte("1"), + result: vv(2, "12"), + ok: true, + }, + { + comment: "entire View", + in: vv(2, "1", "2"), + count: 1, + want: []byte("1"), + result: vv(2, "1", "2"), + ok: true, + }, + { + comment: "spanning across two Views", + in: vv(3, "1", "23"), + count: 2, + want: []byte("12"), + result: vv(3, "12", "3"), + ok: true, + }, + { + comment: "spanning across all Views", + in: vv(5, "1", "23", "45"), + count: 5, + want: []byte("12345"), + result: vv(5, "12345"), + ok: true, + }, + { + comment: "count = 0", + in: vv(1, "1"), + count: 0, + want: []byte{}, + result: vv(1, "1"), + ok: true, + }, + { + comment: "count = size", + in: vv(1, "1"), + count: 1, + want: []byte("1"), + result: vv(1, "1"), + ok: true, + }, + { + comment: "count too large", + in: vv(3, "1", "23"), + count: 4, + want: nil, + result: vv(3, "1", "23"), + ok: false, + }, + { + comment: "empty vv", + in: vv(0, ""), + count: 1, + want: nil, + result: vv(0, ""), + ok: false, + }, + { + comment: "empty vv, count = 0", + in: vv(0, ""), + count: 0, + want: nil, + result: vv(0, ""), + ok: true, + }, + { + comment: "empty views", + in: vv(3, "", "1", "", "23"), + count: 2, + want: []byte("12"), + result: vv(3, "12", "3"), + ok: true, + }, +} + +func TestPullUp(t *testing.T) { + for _, c := range pullUpTestCases { + got, ok := c.in.PullUp(c.count) + + // Is the return value right? + if ok != c.ok { + t.Errorf("Test %q failed when calling PullUp(%d) on %v. Got an ok of %t. Want %t", + c.comment, c.count, c.in, ok, c.ok) + } + if bytes.Compare(got, View(c.want)) != 0 { + t.Errorf("Test %q failed when calling PullUp(%d) on %v. Got %v. Want %v", + c.comment, c.count, c.in, got, c.want) + } + + // Is the underlying structure right? + if !reflect.DeepEqual(c.in, c.result) { + t.Errorf("Test %q failed when calling PullUp(%d). Got vv with structure %v. Wanted %v", + c.comment, c.count, c.in, c.result) + } + } +} diff --git a/pkg/tcpip/link/loopback/loopback.go b/pkg/tcpip/link/loopback/loopback.go index 1e2255bfa..073c84ef9 100644 --- a/pkg/tcpip/link/loopback/loopback.go +++ b/pkg/tcpip/link/loopback/loopback.go @@ -98,13 +98,13 @@ func (e *endpoint) WritePackets(*stack.Route, *stack.GSO, stack.PacketBufferList // WriteRawPacket implements stack.LinkEndpoint.WriteRawPacket. func (e *endpoint) WriteRawPacket(vv buffer.VectorisedView) *tcpip.Error { - // Reject the packet if it's shorter than an ethernet header. - if vv.Size() < header.EthernetMinimumSize { + // There should be an ethernet header at the beginning of vv. + hdr, ok := vv.PullUp(header.EthernetMinimumSize) + if !ok { + // Reject the packet if it's shorter than an ethernet header. return tcpip.ErrBadAddress } - - // There should be an ethernet header at the beginning of vv. - linkHeader := header.Ethernet(vv.First()[:header.EthernetMinimumSize]) + linkHeader := header.Ethernet(hdr) vv.TrimFront(len(linkHeader)) e.dispatcher.DeliverNetworkPacket(e, "" /* remote */, "" /* local */, linkHeader.Type(), stack.PacketBuffer{ Data: vv, diff --git a/pkg/tcpip/link/rawfile/BUILD b/pkg/tcpip/link/rawfile/BUILD index 14b527bc2..9cc08d0e2 100644 --- a/pkg/tcpip/link/rawfile/BUILD +++ b/pkg/tcpip/link/rawfile/BUILD @@ -1,4 +1,4 @@ -load("//tools:defs.bzl", "go_library") +load("//tools:defs.bzl", "go_library", "go_test") package(licenses = ["notice"]) @@ -18,3 +18,10 @@ go_library( "@org_golang_x_sys//unix:go_default_library", ], ) + +go_test( + name = "rawfile_test", + size = "small", + srcs = ["rawfile_test.go"], + library = ":rawfile", +) diff --git a/pkg/tcpip/link/rawfile/rawfile_test.go b/pkg/tcpip/link/rawfile/rawfile_test.go new file mode 100644 index 000000000..8f14ba761 --- /dev/null +++ b/pkg/tcpip/link/rawfile/rawfile_test.go @@ -0,0 +1,46 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +// +build linux + +package rawfile + +import ( + "syscall" + "testing" +) + +func TestNonBlockingWrite3ZeroLength(t *testing.T) { + fd, err := syscall.Open("/dev/null", syscall.O_WRONLY, 0) + if err != nil { + t.Fatalf("failed to open /dev/null: %v", err) + } + defer syscall.Close(fd) + + if err := NonBlockingWrite3(fd, []byte{}, []byte{0}, nil); err != nil { + t.Fatalf("failed to write: %v", err) + } +} + +func TestNonBlockingWrite3Nil(t *testing.T) { + fd, err := syscall.Open("/dev/null", syscall.O_WRONLY, 0) + if err != nil { + t.Fatalf("failed to open /dev/null: %v", err) + } + defer syscall.Close(fd) + + if err := NonBlockingWrite3(fd, nil, []byte{0}, nil); err != nil { + t.Fatalf("failed to write: %v", err) + } +} diff --git a/pkg/tcpip/link/rawfile/rawfile_unsafe.go b/pkg/tcpip/link/rawfile/rawfile_unsafe.go index 44e25d475..92efd0bf8 100644 --- a/pkg/tcpip/link/rawfile/rawfile_unsafe.go +++ b/pkg/tcpip/link/rawfile/rawfile_unsafe.go @@ -76,9 +76,13 @@ func NonBlockingWrite3(fd int, b1, b2, b3 []byte) *tcpip.Error { // We have two buffers. Build the iovec that represents them and issue // a writev syscall. + var base *byte + if len(b1) > 0 { + base = &b1[0] + } iovec := [3]syscall.Iovec{ { - Base: &b1[0], + Base: base, Len: uint64(len(b1)), }, { diff --git a/pkg/tcpip/link/sharedmem/sharedmem_test.go b/pkg/tcpip/link/sharedmem/sharedmem_test.go index 27ea3f531..33f640b85 100644 --- a/pkg/tcpip/link/sharedmem/sharedmem_test.go +++ b/pkg/tcpip/link/sharedmem/sharedmem_test.go @@ -674,7 +674,7 @@ func TestSimpleReceive(t *testing.T) { // Wait for packet to be received, then check it. c.waitForPackets(1, time.After(5*time.Second), "Timeout waiting for packet") c.mu.Lock() - rcvd := []byte(c.packets[0].vv.First()) + rcvd := []byte(c.packets[0].vv.ToView()) c.packets = c.packets[:0] c.mu.Unlock() diff --git a/pkg/tcpip/link/sniffer/sniffer.go b/pkg/tcpip/link/sniffer/sniffer.go index be2537a82..0799c8f4d 100644 --- a/pkg/tcpip/link/sniffer/sniffer.go +++ b/pkg/tcpip/link/sniffer/sniffer.go @@ -171,11 +171,7 @@ func (e *endpoint) GSOMaxSize() uint32 { func (e *endpoint) dumpPacket(prefix string, gso *stack.GSO, protocol tcpip.NetworkProtocolNumber, pkt *stack.PacketBuffer) { writer := e.writer if writer == nil && atomic.LoadUint32(&LogPackets) == 1 { - first := pkt.Header.View() - if len(first) == 0 { - first = pkt.Data.First() - } - logPacket(prefix, protocol, first, gso) + logPacket(prefix, protocol, pkt, gso) } if writer != nil && atomic.LoadUint32(&LogPacketsToPCAP) == 1 { totalLength := pkt.Header.UsedLength() + pkt.Data.Size() @@ -238,7 +234,7 @@ func (e *endpoint) WriteRawPacket(vv buffer.VectorisedView) *tcpip.Error { // Wait implements stack.LinkEndpoint.Wait. func (e *endpoint) Wait() { e.lower.Wait() } -func logPacket(prefix string, protocol tcpip.NetworkProtocolNumber, b buffer.View, gso *stack.GSO) { +func logPacket(prefix string, protocol tcpip.NetworkProtocolNumber, pkt *stack.PacketBuffer, gso *stack.GSO) { // Figure out the network layer info. var transProto uint8 src := tcpip.Address("unknown") @@ -247,28 +243,49 @@ func logPacket(prefix string, protocol tcpip.NetworkProtocolNumber, b buffer.Vie size := uint16(0) var fragmentOffset uint16 var moreFragments bool + + // Create a clone of pkt, including any headers if present. Avoid allocating + // backing memory for the clone. + views := [8]buffer.View{} + vv := buffer.NewVectorisedView(0, views[:0]) + vv.AppendView(pkt.Header.View()) + vv.Append(pkt.Data) + switch protocol { case header.IPv4ProtocolNumber: - ipv4 := header.IPv4(b) + hdr, ok := vv.PullUp(header.IPv4MinimumSize) + if !ok { + return + } + ipv4 := header.IPv4(hdr) fragmentOffset = ipv4.FragmentOffset() moreFragments = ipv4.Flags()&header.IPv4FlagMoreFragments == header.IPv4FlagMoreFragments src = ipv4.SourceAddress() dst = ipv4.DestinationAddress() transProto = ipv4.Protocol() size = ipv4.TotalLength() - uint16(ipv4.HeaderLength()) - b = b[ipv4.HeaderLength():] + vv.TrimFront(int(ipv4.HeaderLength())) id = int(ipv4.ID()) case header.IPv6ProtocolNumber: - ipv6 := header.IPv6(b) + hdr, ok := vv.PullUp(header.IPv6MinimumSize) + if !ok { + return + } + ipv6 := header.IPv6(hdr) src = ipv6.SourceAddress() dst = ipv6.DestinationAddress() transProto = ipv6.NextHeader() size = ipv6.PayloadLength() - b = b[header.IPv6MinimumSize:] + vv.TrimFront(header.IPv6MinimumSize) case header.ARPProtocolNumber: - arp := header.ARP(b) + hdr, ok := vv.PullUp(header.ARPSize) + if !ok { + return + } + vv.TrimFront(header.ARPSize) + arp := header.ARP(hdr) log.Infof( "%s arp %v (%v) -> %v (%v) valid:%v", prefix, @@ -284,7 +301,7 @@ func logPacket(prefix string, protocol tcpip.NetworkProtocolNumber, b buffer.Vie // We aren't guaranteed to have a transport header - it's possible for // writes via raw endpoints to contain only network headers. - if minSize, ok := transportProtocolMinSizes[tcpip.TransportProtocolNumber(transProto)]; ok && len(b) < minSize { + if minSize, ok := transportProtocolMinSizes[tcpip.TransportProtocolNumber(transProto)]; ok && vv.Size() < minSize { log.Infof("%s %v -> %v transport protocol: %d, but no transport header found (possible raw packet)", prefix, src, dst, transProto) return } @@ -297,7 +314,11 @@ func logPacket(prefix string, protocol tcpip.NetworkProtocolNumber, b buffer.Vie switch tcpip.TransportProtocolNumber(transProto) { case header.ICMPv4ProtocolNumber: transName = "icmp" - icmp := header.ICMPv4(b) + hdr, ok := vv.PullUp(header.ICMPv4MinimumSize) + if !ok { + break + } + icmp := header.ICMPv4(hdr) icmpType := "unknown" if fragmentOffset == 0 { switch icmp.Type() { @@ -330,7 +351,11 @@ func logPacket(prefix string, protocol tcpip.NetworkProtocolNumber, b buffer.Vie case header.ICMPv6ProtocolNumber: transName = "icmp" - icmp := header.ICMPv6(b) + hdr, ok := vv.PullUp(header.ICMPv6MinimumSize) + if !ok { + break + } + icmp := header.ICMPv6(hdr) icmpType := "unknown" switch icmp.Type() { case header.ICMPv6DstUnreachable: @@ -361,7 +386,11 @@ func logPacket(prefix string, protocol tcpip.NetworkProtocolNumber, b buffer.Vie case header.UDPProtocolNumber: transName = "udp" - udp := header.UDP(b) + hdr, ok := vv.PullUp(header.UDPMinimumSize) + if !ok { + break + } + udp := header.UDP(hdr) if fragmentOffset == 0 && len(udp) >= header.UDPMinimumSize { srcPort = udp.SourcePort() dstPort = udp.DestinationPort() @@ -371,7 +400,11 @@ func logPacket(prefix string, protocol tcpip.NetworkProtocolNumber, b buffer.Vie case header.TCPProtocolNumber: transName = "tcp" - tcp := header.TCP(b) + hdr, ok := vv.PullUp(header.TCPMinimumSize) + if !ok { + break + } + tcp := header.TCP(hdr) if fragmentOffset == 0 && len(tcp) >= header.TCPMinimumSize { offset := int(tcp.DataOffset()) if offset < header.TCPMinimumSize { diff --git a/pkg/tcpip/network/arp/arp.go b/pkg/tcpip/network/arp/arp.go index 7acbfa0a8..cf73a939e 100644 --- a/pkg/tcpip/network/arp/arp.go +++ b/pkg/tcpip/network/arp/arp.go @@ -93,7 +93,10 @@ func (e *endpoint) WriteHeaderIncludedPacket(r *stack.Route, pkt stack.PacketBuf } func (e *endpoint) HandlePacket(r *stack.Route, pkt stack.PacketBuffer) { - v := pkt.Data.First() + v, ok := pkt.Data.PullUp(header.ARPSize) + if !ok { + return + } h := header.ARP(v) if !h.IsValid() { return diff --git a/pkg/tcpip/network/ipv4/icmp.go b/pkg/tcpip/network/ipv4/icmp.go index c4bf1ba5c..4cbefe5ab 100644 --- a/pkg/tcpip/network/ipv4/icmp.go +++ b/pkg/tcpip/network/ipv4/icmp.go @@ -25,7 +25,11 @@ 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.IPv4(pkt.Data.First()) + h, ok := pkt.Data.PullUp(header.IPv4MinimumSize) + if !ok { + return + } + hdr := header.IPv4(h) // We don't use IsValid() here because ICMP only requires that the IP // header plus 8 bytes of the transport header be included. So it's @@ -34,12 +38,12 @@ func (e *endpoint) handleControl(typ stack.ControlType, extra uint32, pkt stack. // // Drop packet if it doesn't have the basic IPv4 header or if the // original source address doesn't match the endpoint's address. - if len(h) < header.IPv4MinimumSize || h.SourceAddress() != e.id.LocalAddress { + if hdr.SourceAddress() != e.id.LocalAddress { return } - hlen := int(h.HeaderLength()) - if pkt.Data.Size() < hlen || h.FragmentOffset() != 0 { + hlen := int(hdr.HeaderLength()) + if pkt.Data.Size() < hlen || hdr.FragmentOffset() != 0 { // We won't be able to handle this if it doesn't contain the // full IPv4 header, or if it's a fragment not at offset 0 // (because it won't have the transport header). @@ -48,15 +52,15 @@ func (e *endpoint) handleControl(typ stack.ControlType, extra uint32, pkt stack. // Skip the ip header, then deliver control message. pkt.Data.TrimFront(hlen) - p := h.TransportProtocol() - e.dispatcher.DeliverTransportControlPacket(e.id.LocalAddress, h.DestinationAddress(), ProtocolNumber, p, typ, extra, pkt) + p := hdr.TransportProtocol() + e.dispatcher.DeliverTransportControlPacket(e.id.LocalAddress, hdr.DestinationAddress(), ProtocolNumber, p, typ, extra, pkt) } func (e *endpoint) handleICMP(r *stack.Route, pkt stack.PacketBuffer) { stats := r.Stats() received := stats.ICMP.V4PacketsReceived - v := pkt.Data.First() - if len(v) < header.ICMPv4MinimumSize { + v, ok := pkt.Data.PullUp(header.ICMPv4MinimumSize) + if !ok { received.Invalid.Increment() return } diff --git a/pkg/tcpip/network/ipv4/ipv4.go b/pkg/tcpip/network/ipv4/ipv4.go index 104aafbed..17202cc7a 100644 --- a/pkg/tcpip/network/ipv4/ipv4.go +++ b/pkg/tcpip/network/ipv4/ipv4.go @@ -328,7 +328,11 @@ func (e *endpoint) WritePackets(r *stack.Route, gso *stack.GSO, pkts stack.Packe func (e *endpoint) WriteHeaderIncludedPacket(r *stack.Route, pkt stack.PacketBuffer) *tcpip.Error { // The packet already has an IP header, but there are a few required // checks. - ip := header.IPv4(pkt.Data.First()) + h, ok := pkt.Data.PullUp(header.IPv4MinimumSize) + if !ok { + return tcpip.ErrInvalidOptionValue + } + ip := header.IPv4(h) if !ip.IsValid(pkt.Data.Size()) { return tcpip.ErrInvalidOptionValue } @@ -378,7 +382,11 @@ func (e *endpoint) WriteHeaderIncludedPacket(r *stack.Route, pkt stack.PacketBuf // 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 := pkt.Data.First() + headerView, ok := pkt.Data.PullUp(header.IPv4MinimumSize) + if !ok { + r.Stats().IP.MalformedPacketsReceived.Increment() + return + } h := header.IPv4(headerView) if !h.IsValid(pkt.Data.Size()) { r.Stats().IP.MalformedPacketsReceived.Increment() 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? diff --git a/pkg/tcpip/network/ipv6/icmp_test.go b/pkg/tcpip/network/ipv6/icmp_test.go index bd099a7f8..d412ff688 100644 --- a/pkg/tcpip/network/ipv6/icmp_test.go +++ b/pkg/tcpip/network/ipv6/icmp_test.go @@ -166,7 +166,8 @@ func TestICMPCounts(t *testing.T) { }, { typ: header.ICMPv6NeighborSolicit, - size: header.ICMPv6NeighborSolicitMinimumSize}, + size: header.ICMPv6NeighborSolicitMinimumSize, + }, { typ: header.ICMPv6NeighborAdvert, size: header.ICMPv6NeighborAdvertMinimumSize, diff --git a/pkg/tcpip/network/ipv6/ipv6.go b/pkg/tcpip/network/ipv6/ipv6.go index 331b0817b..486725131 100644 --- a/pkg/tcpip/network/ipv6/ipv6.go +++ b/pkg/tcpip/network/ipv6/ipv6.go @@ -171,7 +171,11 @@ func (*endpoint) WriteHeaderIncludedPacket(r *stack.Route, pkt stack.PacketBuffe // 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 := pkt.Data.First() + headerView, ok := pkt.Data.PullUp(header.IPv6MinimumSize) + if !ok { + r.Stats().IP.MalformedPacketsReceived.Increment() + return + } h := header.IPv6(headerView) if !h.IsValid(pkt.Data.Size()) { r.Stats().IP.MalformedPacketsReceived.Increment() diff --git a/pkg/tcpip/stack/forwarder_test.go b/pkg/tcpip/stack/forwarder_test.go index e9c652042..c7c663498 100644 --- a/pkg/tcpip/stack/forwarder_test.go +++ b/pkg/tcpip/stack/forwarder_test.go @@ -70,7 +70,10 @@ func (f *fwdTestNetworkEndpoint) ID() *NetworkEndpointID { func (f *fwdTestNetworkEndpoint) HandlePacket(r *Route, pkt PacketBuffer) { // Consume the network header. - b := pkt.Data.First() + b, ok := pkt.Data.PullUp(fwdTestNetHeaderLen) + if !ok { + return + } pkt.Data.TrimFront(fwdTestNetHeaderLen) // Dispatch the packet to the transport protocol. @@ -473,7 +476,7 @@ func TestForwardingWithFakeResolverPartialTimeout(t *testing.T) { t.Fatal("packet not forwarded") } - b := p.Pkt.Header.View() + b := p.Pkt.Data.ToView() if b[0] != 3 { t.Fatalf("got b[0] = %d, want = 3", b[0]) } @@ -517,7 +520,7 @@ func TestForwardingWithFakeResolverTwoPackets(t *testing.T) { t.Fatal("packet not forwarded") } - b := p.Pkt.Header.View() + b := p.Pkt.Data.ToView() if b[0] != 3 { t.Fatalf("got b[0] = %d, want = 3", b[0]) } @@ -564,7 +567,7 @@ func TestForwardingWithFakeResolverManyPackets(t *testing.T) { t.Fatal("packet not forwarded") } - b := p.Pkt.Header.View() + b := p.Pkt.Data.ToView() if b[0] != 3 { t.Fatalf("got b[0] = %d, want = 3", b[0]) } @@ -619,7 +622,7 @@ 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.Header.View() + b := p.Pkt.Data.ToView() if b[0] < 8 { t.Fatalf("got b[0] = %d, want b[0] >= 8", b[0]) } diff --git a/pkg/tcpip/stack/iptables.go b/pkg/tcpip/stack/iptables.go index 6c0a4b24d..6b91159d4 100644 --- a/pkg/tcpip/stack/iptables.go +++ b/pkg/tcpip/stack/iptables.go @@ -212,6 +212,11 @@ func (it *IPTables) Check(hook Hook, pkt PacketBuffer) bool { // CheckPackets runs pkts through the rules for hook and returns a map of packets that // should not go forward. // +// Precondition: pkt is a IPv4 packet of at least length header.IPv4MinimumSize. +// +// TODO(gvisor.dev/issue/170): pk.NetworkHeader will always be set as a +// precondition. +// // NOTE: unlike the Check API the returned map contains packets that should be // dropped. func (it *IPTables) CheckPackets(hook Hook, pkts PacketBufferList) (drop map[*PacketBuffer]struct{}) { @@ -226,7 +231,9 @@ func (it *IPTables) CheckPackets(hook Hook, pkts PacketBufferList) (drop map[*Pa return drop } -// Precondition: pkt.NetworkHeader is set. +// Precondition: pkt is a IPv4 packet of at least length header.IPv4MinimumSize. +// TODO(gvisor.dev/issue/170): pk.NetworkHeader will always be set as a +// precondition. func (it *IPTables) checkChain(hook Hook, pkt PacketBuffer, table Table, ruleIdx int) chainVerdict { // Start from ruleIdx and walk the list of rules until a rule gives us // a verdict. @@ -271,14 +278,21 @@ func (it *IPTables) checkChain(hook Hook, pkt PacketBuffer, table Table, ruleIdx return chainDrop } -// Precondition: pk.NetworkHeader is set. +// Precondition: pkt is a IPv4 packet of at least length header.IPv4MinimumSize. +// TODO(gvisor.dev/issue/170): pk.NetworkHeader will always be set as a +// precondition. func (it *IPTables) checkRule(hook Hook, pkt PacketBuffer, table Table, ruleIdx int) (RuleVerdict, int) { rule := table.Rules[ruleIdx] // If pkt.NetworkHeader hasn't been set yet, it will be contained in - // pkt.Data.First(). + // pkt.Data. if pkt.NetworkHeader == nil { - pkt.NetworkHeader = pkt.Data.First() + var ok bool + pkt.NetworkHeader, ok = pkt.Data.PullUp(header.IPv4MinimumSize) + if !ok { + // Precondition has been violated. + panic(fmt.Sprintf("iptables checks require IPv4 headers of at least %d bytes", header.IPv4MinimumSize)) + } } // Check whether the packet matches the IP header filter. diff --git a/pkg/tcpip/stack/iptables_targets.go b/pkg/tcpip/stack/iptables_targets.go index 7b4543caf..8be61f4b1 100644 --- a/pkg/tcpip/stack/iptables_targets.go +++ b/pkg/tcpip/stack/iptables_targets.go @@ -96,9 +96,12 @@ func (rt RedirectTarget) Action(pkt PacketBuffer) (RuleVerdict, int) { newPkt := pkt.Clone() // Set network header. - headerView := newPkt.Data.First() + headerView, ok := newPkt.Data.PullUp(header.IPv4MinimumSize) + if !ok { + return RuleDrop, 0 + } netHeader := header.IPv4(headerView) - newPkt.NetworkHeader = headerView[:header.IPv4MinimumSize] + newPkt.NetworkHeader = headerView hlen := int(netHeader.HeaderLength()) tlen := int(netHeader.TotalLength()) @@ -117,10 +120,14 @@ func (rt RedirectTarget) Action(pkt PacketBuffer) (RuleVerdict, int) { if newPkt.TransportHeader != nil { udpHeader = header.UDP(newPkt.TransportHeader) } else { - if len(pkt.Data.First()) < header.UDPMinimumSize { + if pkt.Data.Size() < header.UDPMinimumSize { + return RuleDrop, 0 + } + hdr, ok := newPkt.Data.PullUp(header.UDPMinimumSize) + if !ok { return RuleDrop, 0 } - udpHeader = header.UDP(newPkt.Data.First()) + udpHeader = header.UDP(hdr) } udpHeader.SetDestinationPort(rt.MinPort) case header.TCPProtocolNumber: @@ -128,10 +135,14 @@ func (rt RedirectTarget) Action(pkt PacketBuffer) (RuleVerdict, int) { if newPkt.TransportHeader != nil { tcpHeader = header.TCP(newPkt.TransportHeader) } else { - if len(pkt.Data.First()) < header.TCPMinimumSize { + if pkt.Data.Size() < header.TCPMinimumSize { return RuleDrop, 0 } - tcpHeader = header.TCP(newPkt.TransportHeader) + hdr, ok := newPkt.Data.PullUp(header.TCPMinimumSize) + if !ok { + return RuleDrop, 0 + } + tcpHeader = header.TCP(hdr) } // TODO(gvisor.dev/issue/170): Need to recompute checksum // and implement nat connection tracking to support TCP. diff --git a/pkg/tcpip/stack/nic.go b/pkg/tcpip/stack/nic.go index 016dbe15e..0c2b1f36a 100644 --- a/pkg/tcpip/stack/nic.go +++ b/pkg/tcpip/stack/nic.go @@ -1203,12 +1203,12 @@ func (n *NIC) DeliverNetworkPacket(linkEP LinkEndpoint, remote, local tcpip.Link n.stack.stats.IP.PacketsReceived.Increment() } - if len(pkt.Data.First()) < netProto.MinimumPacketSize() { + netHeader, ok := pkt.Data.PullUp(netProto.MinimumPacketSize()) + if !ok { n.stack.stats.MalformedRcvdPackets.Increment() return } - - src, dst := netProto.ParseAddresses(pkt.Data.First()) + src, dst := netProto.ParseAddresses(netHeader) 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 @@ -1289,22 +1289,8 @@ func (n *NIC) DeliverNetworkPacket(linkEP LinkEndpoint, remote, local tcpip.Link func (n *NIC) forwardPacket(r *Route, protocol tcpip.NetworkProtocolNumber, pkt PacketBuffer) { // TODO(b/143425874) Decrease the TTL field in forwarded packets. - - firstData := pkt.Data.First() - pkt.Data.RemoveFirst() - - if linkHeaderLen := int(n.linkEP.MaxHeaderLength()); linkHeaderLen == 0 { - pkt.Header = buffer.NewPrependableFromView(firstData) - } else { - firstDataLen := len(firstData) - - // pkt.Header should have enough capacity to hold n.linkEP's headers. - pkt.Header = buffer.NewPrependable(firstDataLen + linkHeaderLen) - - // TODO(b/151227689): avoid copying the packet when forwarding - if n := copy(pkt.Header.Prepend(firstDataLen), firstData); n != firstDataLen { - panic(fmt.Sprintf("copied %d bytes, expected %d", n, firstDataLen)) - } + if linkHeaderLen := int(n.linkEP.MaxHeaderLength()); linkHeaderLen != 0 { + pkt.Header = buffer.NewPrependable(linkHeaderLen) } if err := n.linkEP.WritePacket(r, nil /* gso */, protocol, pkt); err != nil { @@ -1332,12 +1318,13 @@ func (n *NIC) DeliverTransportPacket(r *Route, protocol tcpip.TransportProtocolN // validly formed. n.stack.demux.deliverRawPacket(r, protocol, pkt) - if len(pkt.Data.First()) < transProto.MinimumPacketSize() { + transHeader, ok := pkt.Data.PullUp(transProto.MinimumPacketSize()) + if !ok { n.stack.stats.MalformedRcvdPackets.Increment() return } - srcPort, dstPort, err := transProto.ParsePorts(pkt.Data.First()) + srcPort, dstPort, err := transProto.ParsePorts(transHeader) if err != nil { n.stack.stats.MalformedRcvdPackets.Increment() return @@ -1375,11 +1362,12 @@ func (n *NIC) DeliverTransportControlPacket(local, remote tcpip.Address, net tcp // ICMPv4 only guarantees that 8 bytes of the transport protocol will // be present in the payload. We know that the ports are within the // first 8 bytes for all known transport protocols. - if len(pkt.Data.First()) < 8 { + transHeader, ok := pkt.Data.PullUp(8) + if !ok { return } - srcPort, dstPort, err := transProto.ParsePorts(pkt.Data.First()) + srcPort, dstPort, err := transProto.ParsePorts(transHeader) if err != nil { return } diff --git a/pkg/tcpip/stack/packet_buffer.go b/pkg/tcpip/stack/packet_buffer.go index dc125f25e..7d36f8e84 100644 --- a/pkg/tcpip/stack/packet_buffer.go +++ b/pkg/tcpip/stack/packet_buffer.go @@ -37,7 +37,13 @@ type PacketBuffer struct { Data buffer.VectorisedView // Header holds the headers of outbound packets. As a packet is passed - // down the stack, each layer adds to Header. + // down the stack, each layer adds to Header. Note that forwarded + // packets don't populate Headers on their way out -- their headers and + // payload are never parsed out and remain in Data. + // + // TODO(gvisor.dev/issue/170): Forwarded packets don't currently + // populate Header, but should. This will be doable once early parsing + // (https://github.com/google/gvisor/pull/1995) is supported. Header buffer.Prependable // These fields are used by both inbound and outbound packets. They diff --git a/pkg/tcpip/stack/stack_test.go b/pkg/tcpip/stack/stack_test.go index c7634ceb1..d45d2cc1f 100644 --- a/pkg/tcpip/stack/stack_test.go +++ b/pkg/tcpip/stack/stack_test.go @@ -95,16 +95,18 @@ func (f *fakeNetworkEndpoint) HandlePacket(r *stack.Route, pkt stack.PacketBuffe f.proto.packetCount[int(f.id.LocalAddress[0])%len(f.proto.packetCount)]++ // Consume the network header. - b := pkt.Data.First() + b, ok := pkt.Data.PullUp(fakeNetHeaderLen) + if !ok { + return + } pkt.Data.TrimFront(fakeNetHeaderLen) // Handle control packets. if b[2] == uint8(fakeControlProtocol) { - nb := pkt.Data.First() - if len(nb) < fakeNetHeaderLen { + 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) return diff --git a/pkg/tcpip/stack/transport_test.go b/pkg/tcpip/stack/transport_test.go index 3084e6593..a611e44ab 100644 --- a/pkg/tcpip/stack/transport_test.go +++ b/pkg/tcpip/stack/transport_test.go @@ -642,10 +642,11 @@ func TestTransportForwarding(t *testing.T) { t.Fatal("Response packet not forwarded") } - if dst := p.Pkt.Header.View()[0]; dst != 3 { + hdrs := p.Pkt.Data.ToView() + if dst := hdrs[0]; dst != 3 { t.Errorf("Response packet has incorrect destination addresss: got = %d, want = 3", dst) } - if src := p.Pkt.Header.View()[1]; src != 1 { + if src := hdrs[1]; src != 1 { t.Errorf("Response packet has incorrect source addresss: got = %d, want = 3", src) } } diff --git a/pkg/tcpip/transport/icmp/endpoint.go b/pkg/tcpip/transport/icmp/endpoint.go index feef8dca0..b1d820372 100644 --- a/pkg/tcpip/transport/icmp/endpoint.go +++ b/pkg/tcpip/transport/icmp/endpoint.go @@ -747,15 +747,15 @@ func (e *endpoint) HandlePacket(r *stack.Route, id stack.TransportEndpointID, pk // Only accept echo replies. switch e.NetProto { case header.IPv4ProtocolNumber: - h := header.ICMPv4(pkt.Data.First()) - if h.Type() != header.ICMPv4EchoReply { + h, ok := pkt.Data.PullUp(header.ICMPv4MinimumSize) + if !ok || header.ICMPv4(h).Type() != header.ICMPv4EchoReply { e.stack.Stats().DroppedPackets.Increment() e.stats.ReceiveErrors.MalformedPacketsReceived.Increment() return } case header.IPv6ProtocolNumber: - h := header.ICMPv6(pkt.Data.First()) - if h.Type() != header.ICMPv6EchoReply { + h, ok := pkt.Data.PullUp(header.ICMPv6MinimumSize) + if !ok || header.ICMPv6(h).Type() != header.ICMPv6EchoReply { e.stack.Stats().DroppedPackets.Increment() e.stats.ReceiveErrors.MalformedPacketsReceived.Increment() return diff --git a/pkg/tcpip/transport/tcp/segment.go b/pkg/tcpip/transport/tcp/segment.go index 40461fd31..7712ce652 100644 --- a/pkg/tcpip/transport/tcp/segment.go +++ b/pkg/tcpip/transport/tcp/segment.go @@ -144,7 +144,11 @@ 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 := header.TCP(s.data.First()) + 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: @@ -156,12 +160,16 @@ 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(h.DataOffset()) - if offset < header.TCPMinimumSize || offset > len(h) { + offset := int(hdr.DataOffset()) + if offset < header.TCPMinimumSize { + return false + } + hdrWithOpts, ok := s.data.PullUp(offset) + if !ok { return false } - s.options = []byte(h[header.TCPMinimumSize:offset]) + s.options = []byte(hdrWithOpts[header.TCPMinimumSize:]) s.parsedOptions = header.ParseTCPOptions(s.options) // Query the link capabilities to decide if checksum validation is @@ -173,18 +181,19 @@ func (s *segment) parse() bool { s.data.TrimFront(offset) } if verifyChecksum { - s.csum = h.Checksum() + hdr = header.TCP(hdrWithOpts) + s.csum = hdr.Checksum() xsum := s.route.PseudoHeaderChecksum(ProtocolNumber, uint16(s.data.Size())) - xsum = h.CalculateChecksum(xsum) + xsum = hdr.CalculateChecksum(xsum) s.data.TrimFront(offset) xsum = header.ChecksumVV(s.data, xsum) s.csumValid = xsum == 0xffff } - s.sequenceNumber = seqnum.Value(h.SequenceNumber()) - s.ackNumber = seqnum.Value(h.AckNumber()) - s.flags = h.Flags() - s.window = seqnum.Size(h.WindowSize()) + s.sequenceNumber = seqnum.Value(hdr.SequenceNumber()) + s.ackNumber = seqnum.Value(hdr.AckNumber()) + s.flags = hdr.Flags() + s.window = seqnum.Size(hdr.WindowSize()) return true } diff --git a/pkg/tcpip/transport/tcp/tcp_test.go b/pkg/tcpip/transport/tcp/tcp_test.go index ab1014c7f..286c66cf5 100644 --- a/pkg/tcpip/transport/tcp/tcp_test.go +++ b/pkg/tcpip/transport/tcp/tcp_test.go @@ -3548,7 +3548,7 @@ func TestReceivedInvalidSegmentCountIncrement(t *testing.T) { AckNum: c.IRS.Add(1), RcvWnd: 30000, }) - tcpbuf := vv.First()[header.IPv4MinimumSize:] + tcpbuf := vv.ToView()[header.IPv4MinimumSize:] tcpbuf[header.TCPDataOffset] = ((header.TCPMinimumSize - 1) / 4) << 4 c.SendSegment(vv) @@ -3575,7 +3575,7 @@ func TestReceivedIncorrectChecksumIncrement(t *testing.T) { AckNum: c.IRS.Add(1), RcvWnd: 30000, }) - tcpbuf := vv.First()[header.IPv4MinimumSize:] + tcpbuf := vv.ToView()[header.IPv4MinimumSize:] // Overwrite a byte in the payload which should cause checksum // verification to fail. tcpbuf[(tcpbuf[header.TCPDataOffset]>>4)*4] = 0x4 diff --git a/pkg/tcpip/transport/udp/endpoint.go b/pkg/tcpip/transport/udp/endpoint.go index edb54f0be..756ab913a 100644 --- a/pkg/tcpip/transport/udp/endpoint.go +++ b/pkg/tcpip/transport/udp/endpoint.go @@ -1250,8 +1250,8 @@ 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 := header.UDP(pkt.Data.First()) - if int(hdr.Length()) > pkt.Data.Size() { + hdr, ok := pkt.Data.PullUp(header.UDPMinimumSize) + if !ok || int(header.UDP(hdr).Length()) > pkt.Data.Size() { // Malformed packet. e.stack.Stats().UDP.MalformedPacketsReceived.Increment() e.stats.ReceiveErrors.MalformedPacketsReceived.Increment() @@ -1286,7 +1286,7 @@ func (e *endpoint) HandlePacket(r *stack.Route, id stack.TransportEndpointID, pk senderAddress: tcpip.FullAddress{ NIC: r.NICID(), Addr: id.RemoteAddress, - Port: hdr.SourcePort(), + Port: header.UDP(hdr).SourcePort(), }, } packet.data = pkt.Data diff --git a/pkg/tcpip/transport/udp/protocol.go b/pkg/tcpip/transport/udp/protocol.go index 6e31a9bac..52af6de22 100644 --- a/pkg/tcpip/transport/udp/protocol.go +++ b/pkg/tcpip/transport/udp/protocol.go @@ -68,8 +68,13 @@ func (*protocol) ParsePorts(v buffer.View) (src, dst uint16, err *tcpip.Error) { // 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. - hdr := header.UDP(pkt.Data.First()) - if int(hdr.Length()) > pkt.Data.Size() { + 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() { // Malformed packet. r.Stack().Stats().UDP.MalformedPacketsReceived.Increment() return true |