diff options
Diffstat (limited to 'pkg/tcpip/network/ipv4/ipv4.go')
| -rw-r--r-- | pkg/tcpip/network/ipv4/ipv4.go | 45 |
1 files changed, 28 insertions, 17 deletions
diff --git a/pkg/tcpip/network/ipv4/ipv4.go b/pkg/tcpip/network/ipv4/ipv4.go index 1efe6297a..dd4251d78 100644 --- a/pkg/tcpip/network/ipv4/ipv4.go +++ b/pkg/tcpip/network/ipv4/ipv4.go @@ -566,21 +566,6 @@ func (e *endpoint) handlePacket(pkt *stack.PacketBuffer) { stats.IP.MalformedPacketsReceived.Increment() return } - srcAddr := h.SourceAddress() - dstAddr := h.DestinationAddress() - - addressEndpoint := e.AcquireAssignedAddress(dstAddr, e.nic.Promiscuous(), stack.CanBePrimaryEndpoint) - if addressEndpoint == nil { - if !e.protocol.Forwarding() { - stats.IP.InvalidDestinationAddressesReceived.Increment() - return - } - - _ = e.forwardPacket(pkt) - return - } - subnet := addressEndpoint.AddressWithPrefix().Subnet() - addressEndpoint.DecRef() // There has been some confusion regarding verifying checksums. We need // just look for negative 0 (0xffff) as the checksum, as it's not possible to @@ -608,16 +593,42 @@ func (e *endpoint) handlePacket(pkt *stack.PacketBuffer) { return } + srcAddr := h.SourceAddress() + dstAddr := h.DestinationAddress() + // As per RFC 1122 section 3.2.1.3: // When a host sends any datagram, the IP source address MUST // be one of its own IP addresses (but not a broadcast or // multicast address). - if directedBroadcast := subnet.IsBroadcast(srcAddr); directedBroadcast || srcAddr == header.IPv4Broadcast || header.IsV4MulticastAddress(srcAddr) { + if srcAddr == header.IPv4Broadcast || header.IsV4MulticastAddress(srcAddr) { stats.IP.InvalidSourceAddressesReceived.Increment() return } + // Make sure the source address is not a subnet-local broadcast address. + if addressEndpoint := e.AcquireAssignedAddress(srcAddr, false /* createTemp */, stack.NeverPrimaryEndpoint); addressEndpoint != nil { + subnet := addressEndpoint.Subnet() + addressEndpoint.DecRef() + if subnet.IsBroadcast(srcAddr) { + stats.IP.InvalidSourceAddressesReceived.Increment() + return + } + } - pkt.NetworkPacketInfo.LocalAddressBroadcast = subnet.IsBroadcast(dstAddr) || dstAddr == header.IPv4Broadcast + // 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. + if addressEndpoint := e.AcquireAssignedAddress(dstAddr, e.nic.Promiscuous(), stack.CanBePrimaryEndpoint); addressEndpoint != nil { + subnet := addressEndpoint.AddressWithPrefix().Subnet() + addressEndpoint.DecRef() + pkt.NetworkPacketInfo.LocalAddressBroadcast = subnet.IsBroadcast(dstAddr) || dstAddr == header.IPv4Broadcast + } else if !e.IsInGroup(dstAddr) { + if !e.protocol.Forwarding() { + stats.IP.InvalidDestinationAddressesReceived.Increment() + return + } + + _ = e.forwardPacket(pkt) + return + } // iptables filtering. All packets that reach here are intended for // this machine and will not be forwarded. |