diff options
| author | Kevin Krakauer <krakauer@google.com> | 2019-11-25 08:35:09 -0800 |
|---|---|---|
| committer | gVisor bot <gvisor-bot@google.com> | 2019-11-25 09:11:05 -0800 |
| commit | 2b1b51f1d7dd96f14b0af3b2663c33bc7ab67f63 (patch) | |
| tree | 90cce55e1f024d32c5dc4a028c436657a4fd6245 /pkg/tcpip | |
| parent | c3b93afeafeff4555b57aa22c2a91375f9e38e28 (diff) | |
Fix panic in sniffer.
Packets written via SOCK_RAW are guaranteed to have network headers, but not
transport headers. Check first whether there are enough bytes left in the packet
to contain a transport header before attempting to parse it.
PiperOrigin-RevId: 282363895
Diffstat (limited to 'pkg/tcpip')
| -rw-r--r-- | pkg/tcpip/link/sniffer/sniffer.go | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/pkg/tcpip/link/sniffer/sniffer.go b/pkg/tcpip/link/sniffer/sniffer.go index 767f14303..3392b7edd 100644 --- a/pkg/tcpip/link/sniffer/sniffer.go +++ b/pkg/tcpip/link/sniffer/sniffer.go @@ -49,6 +49,13 @@ var LogPackets uint32 = 1 // LogPacketsToFile must be accessed atomically. var LogPacketsToFile uint32 = 1 +var transportProtocolMinSizes map[tcpip.TransportProtocolNumber]int = map[tcpip.TransportProtocolNumber]int{ + header.ICMPv4ProtocolNumber: header.IPv4MinimumSize, + header.ICMPv6ProtocolNumber: header.IPv6MinimumSize, + header.UDPProtocolNumber: header.UDPMinimumSize, + header.TCPProtocolNumber: header.TCPMinimumSize, +} + type endpoint struct { dispatcher stack.NetworkDispatcher lower stack.LinkEndpoint @@ -333,6 +340,13 @@ func logPacket(prefix string, protocol tcpip.NetworkProtocolNumber, b buffer.Vie return } + // 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 { + log.Infof("%s %v -> %v transport protocol: %d, but no transport header found (possible raw packet)", prefix, src, dst, transProto) + return + } + // Figure out the transport layer info. transName := "unknown" srcPort := uint16(0) |