Support owner matching for iptables.

This feature will match UID and GID of the packet creator, for locally
generated packets. This match is only valid in the OUTPUT and POSTROUTING
chains. Forwarded packets do not have any socket associated with them.
Packets from kernel threads do have a socket, but usually no owner.

1 files changed, 9 insertions, 0 deletions

diff --git a/pkg/tcpip/transport/raw/endpoint.go b/pkg/tcpip/transport/raw/endpoint.go
index 536dafd1e..337bc1c71 100644
--- a/pkg/tcpip/transport/raw/endpoint.go
+++ b/pkg/tcpip/transport/raw/endpoint.go
@@ -80,6 +80,9 @@ type endpoint struct {
 	// Connect(), and is valid only when conneted is true.
 	route stack.Route                  `state:"manual"`
 	stats tcpip.TransportEndpointStats `state:"nosave"`
+
+	// owner is used to get uid and gid of the packet.
+	owner tcpip.PacketOwner
 }
 
 // NewEndpoint returns a raw  endpoint for the given protocols.
@@ -159,6 +162,10 @@ func (e *endpoint) Close() {
 // ModerateRecvBuf implements tcpip.Endpoint.ModerateRecvBuf.
 func (e *endpoint) ModerateRecvBuf(copied int) {}
 
+func (e *endpoint) SetOwner(owner tcpip.PacketOwner) {
+	e.owner = owner
+}
+
 // IPTables implements tcpip.Endpoint.IPTables.
 func (e *endpoint) IPTables() (stack.IPTables, error) {
 	return e.stack.IPTables(), nil
@@ -348,10 +355,12 @@ func (e *endpoint) finishWrite(payloadBytes []byte, route *stack.Route) (int64,
 			}
 			break
 		}
+
 		hdr := buffer.NewPrependable(len(payloadBytes) + int(route.MaxHeaderLength()))
 		if err := route.WritePacket(nil /* gso */, stack.NetworkHeaderParams{Protocol: e.TransProto, TTL: route.DefaultTTL(), TOS: stack.DefaultTOS}, stack.PacketBuffer{
 			Header: hdr,
 			Data:   buffer.View(payloadBytes).ToVectorisedView(),
+			Owner:  e.owner,
 		}); err != nil {
 			return 0, nil, err
 		}