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Fix: UDP packet buffer leak (#82)

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This commit is contained in:
xjasonlyu
2022-02-02 21:29:27 +08:00
parent bdf85afa3e
commit 6547625688
1 changed files with 25 additions and 14 deletions
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core/stack/udp.go
+25 -14
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@@ -12,14 +12,14 @@ import (
)
const (
// udpNoChecksum disables UDP checksum.
// udpNoChecksum disables UDP checksum if set to true.
udpNoChecksum = true
)
func withUDPHandler() Option {
return func(s *Stack) error {
udpHandlePacket := func(id stack.TransportEndpointID, pkt *stack.PacketBuffer) bool {
// Ref: gVisor pkg/tcpip/transport/udp/endpoint.go HandlePacket
// Ref: gVisor pkg/tcpip/transport/udp/endpoint.go HandlePacket.
udpHdr := header.UDP(pkt.TransportHeader().View())
if int(udpHdr.Length()) > pkt.Data().Size()+header.UDPMinimumSize {
// Malformed packet.
@@ -122,6 +122,7 @@ func sendUDP(r *stack.Route, data buffer.VectorisedView, localPort, remotePort u
ReserveHeaderBytes: header.UDPMinimumSize + int(r.MaxHeaderLength()),
Data: data,
})
defer pkt.DecRef()
// Initialize the UDP header.
udpHdr := header.UDP(pkt.TransportHeader().Push(header.UDPMinimumSize))
@@ -163,19 +164,29 @@ func sendUDP(r *stack.Route, data buffer.VectorisedView, localPort, remotePort u
return nil
}
// Ref: gVisor pkg/tcpip/transport/udp/endpoint.go verifyChecksum.
// verifyChecksum verifies the checksum unless RX checksum offload is enabled.
// On IPv4, UDP checksum is optional, and a zero value means the transmitter
// omitted the checksum generation (RFC768).
// On IPv6, UDP checksum is not optional (RFC2460 Section 8.1).
func verifyChecksum(hdr header.UDP, pkt *stack.PacketBuffer) bool {
if !pkt.RXTransportChecksumValidated &&
(hdr.Checksum() != 0 || pkt.NetworkProtocolNumber == header.IPv6ProtocolNumber) {
netHdr := pkt.Network()
xsum := header.PseudoHeaderChecksum(udp.ProtocolNumber, netHdr.DestinationAddress(), netHdr.SourceAddress(), hdr.Length())
for _, v := range pkt.Data().Views() {
xsum = header.Checksum(v, xsum)
}
return hdr.CalculateChecksum(xsum) == 0xffff
if pkt.RXTransportChecksumValidated {
return true
}
return true
// On IPv4, UDP checksum is optional, and a zero value means the transmitter
// omitted the checksum generation, as per RFC 768:
//
// An all zero transmitted checksum value means that the transmitter
// generated no checksum (for debugging or for higher level protocols that
// don't care).
//
// On IPv6, UDP checksum is not optional, as per RFC 2460 Section 8.1:
//
// Unlike IPv4, when UDP packets are originated by an IPv6 node, the UDP
// checksum is not optional.
if pkt.NetworkProtocolNumber == header.IPv4ProtocolNumber && hdr.Checksum() == 0 {
return true
}
netHdr := pkt.Network()
payloadChecksum := pkt.Data().AsRange().Checksum()
return hdr.IsChecksumValid(netHdr.SourceAddress(), netHdr.DestinationAddress(), payloadChecksum)
}