go
/
gvisor
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Fix panic when logging raw packets via sniffer. 

Sniffer assumed that outgoing packets have transport headers, but
users can write packets via SOCK_RAW with arbitrary transport headers that
netstack doesn't know about. We now explicitly check for the presence of network
and transport headers before assuming they exist.

PiperOrigin-RevId: 280594395
This commit is contained in:
Kevin Krakauer 2019-11-14 22:54:01 -08:00 committed by gVisor bot
parent af323eb7c1
commit 23574b1b87
1 changed files with 147 additions and 144 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

29
pkg/tcpip/link/sniffer/sniffer.go
View File

@ -118,7 +118,7 @@ func NewWithFile(lower stack.LinkEndpoint, file *os.File, snapLen uint32) (stack
// logs the packet before forwarding to the actual dispatcher.
func (e *endpoint) DeliverNetworkPacket(linkEP stack.LinkEndpoint, remote, local tcpip.LinkAddress, protocol tcpip.NetworkProtocolNumber, pkt tcpip.PacketBuffer) {
if atomic.LoadUint32(&LogPackets) == 1 && e.file == nil {
logPacket("recv", protocol, pkt.Data.First(), nil)
logPacket("recv", protocol, pkt, nil)
}
if e.file != nil && atomic.LoadUint32(&LogPacketsToFile) == 1 {
vs := pkt.Data.Views()
@ -195,7 +195,7 @@ func (e *endpoint) GSOMaxSize() uint32 {
func (e *endpoint) dumpPacket(gso *stack.GSO, protocol tcpip.NetworkProtocolNumber, pkt tcpip.PacketBuffer) {
if atomic.LoadUint32(&LogPackets) == 1 && e.file == nil {
logPacket("send", protocol, pkt.Header.View(), gso)
logPacket("send", protocol, pkt, gso)
}
if e.file != nil && atomic.LoadUint32(&LogPacketsToFile) == 1 {
hdrBuf := pkt.Header.View()
@ -247,7 +247,7 @@ func (e *endpoint) WritePackets(r *stack.Route, gso *stack.GSO, hdrs []stack.Pac
// WriteRawPacket implements stack.LinkEndpoint.WriteRawPacket.
func (e *endpoint) WriteRawPacket(vv buffer.VectorisedView) *tcpip.Error {
if atomic.LoadUint32(&LogPackets) == 1 && e.file == nil {
logPacket("send", 0, buffer.View("[raw packet, no header available]"), nil /* gso */)
logPacket("send raw packet", 0, tcpip.PacketBuffer{}, nil /* gso */)
}
if e.file != nil && atomic.LoadUint32(&LogPacketsToFile) == 1 {
length := vv.Size()
@ -289,7 +289,7 @@ func logVectorisedView(vv buffer.VectorisedView, length int, buf *bytes.Buffer)
// Wait implements stack.LinkEndpoint.Wait.
func (*endpoint) Wait() {}
func logPacket(prefix string, protocol tcpip.NetworkProtocolNumber, b buffer.View, gso *stack.GSO) {
func logPacket(prefix string, protocol tcpip.NetworkProtocolNumber, pkt tcpip.PacketBuffer, gso *stack.GSO) {
// Figure out the network layer info.
var transProto uint8
src := tcpip.Address("unknown")
@ -298,28 +298,28 @@ func logPacket(prefix string, protocol tcpip.NetworkProtocolNumber, b buffer.Vie
size := uint16(0)
var fragmentOffset uint16
var moreFragments bool
if pkt.NetworkHeader != nil {
switch protocol {
case header.IPv4ProtocolNumber:
ipv4 := header.IPv4(b)
ipv4 := header.IPv4(pkt.NetworkHeader)
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():]
id = int(ipv4.ID())
case header.IPv6ProtocolNumber:
ipv6 := header.IPv6(b)
ipv6 := header.IPv6(pkt.NetworkHeader)
src = ipv6.SourceAddress()
dst = ipv6.DestinationAddress()
transProto = ipv6.NextHeader()
size = ipv6.PayloadLength()
b = b[header.IPv6MinimumSize:]
case header.ARPProtocolNumber:
arp := header.ARP(b)
arp := header.ARP(pkt.NetworkHeader)
log.Infof(
"%s arp %v (%v) -> %v (%v) valid:%v",
prefix,
@ -332,16 +332,18 @@ func logPacket(prefix string, protocol tcpip.NetworkProtocolNumber, b buffer.Vie
log.Infof("%s unknown network protocol", prefix)
return
}
}
// Figure out the transport layer info.
transName := "unknown"
srcPort := uint16(0)
dstPort := uint16(0)
details := ""
if pkt.TransportHeader != nil {
switch tcpip.TransportProtocolNumber(transProto) {
case header.ICMPv4ProtocolNumber:
transName = "icmp"
icmp := header.ICMPv4(b)
icmp := header.ICMPv4(pkt.TransportHeader)
icmpType := "unknown"
if fragmentOffset == 0 {
switch icmp.Type() {
@ -374,7 +376,7 @@ func logPacket(prefix string, protocol tcpip.NetworkProtocolNumber, b buffer.Vie
case header.ICMPv6ProtocolNumber:
transName = "icmp"
icmp := header.ICMPv6(b)
icmp := header.ICMPv6(pkt.TransportHeader)
icmpType := "unknown"
switch icmp.Type() {
case header.ICMPv6DstUnreachable:
@ -405,7 +407,7 @@ func logPacket(prefix string, protocol tcpip.NetworkProtocolNumber, b buffer.Vie
case header.UDPProtocolNumber:
transName = "udp"
udp := header.UDP(b)
udp := header.UDP(pkt.TransportHeader)
if fragmentOffset == 0 && len(udp) >= header.UDPMinimumSize {
srcPort = udp.SourcePort()
dstPort = udp.DestinationPort()
@ -415,7 +417,7 @@ func logPacket(prefix string, protocol tcpip.NetworkProtocolNumber, b buffer.Vie
case header.TCPProtocolNumber:
transName = "tcp"
tcp := header.TCP(b)
tcp := header.TCP(pkt.TransportHeader)
if fragmentOffset == 0 && len(tcp) >= header.TCPMinimumSize {
offset := int(tcp.DataOffset())
if offset < header.TCPMinimumSize {
@ -451,6 +453,7 @@ func logPacket(prefix string, protocol tcpip.NetworkProtocolNumber, b buffer.Vie
log.Infof("%s %v -> %v unknown transport protocol: %d", prefix, src, dst, transProto)
return
}
}
if gso != nil {
details += fmt.Sprintf(" gso: %+v", gso)