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.

2 files changed, 10 insertions, 1 deletions

diff --git a/pkg/tcpip/stack/packet_buffer.go b/pkg/tcpip/stack/packet_buffer.go
index 9505a4e92..9367de180 100644
--- a/pkg/tcpip/stack/packet_buffer.go
+++ b/pkg/tcpip/stack/packet_buffer.go
@@ -13,7 +13,10 @@
 
 package stack
 
-import "gvisor.dev/gvisor/pkg/tcpip/buffer"
+import (
+	"gvisor.dev/gvisor/pkg/tcpip"
+	"gvisor.dev/gvisor/pkg/tcpip/buffer"
+)
 
 // A PacketBuffer contains all the data of a network packet.
 //
@@ -59,6 +62,10 @@ type PacketBuffer struct {
 	// Hash is the transport layer hash of this packet. A value of zero
 	// indicates no valid hash has been set.
 	Hash uint32
+
+	// Owner is implemented by task to get the uid and gid.
+	// Only set for locally generated packets.
+	Owner tcpip.PacketOwner
 }
 
 // Clone makes a copy of pk. It clones the Data field, which creates a new
diff --git a/pkg/tcpip/stack/transport_test.go b/pkg/tcpip/stack/transport_test.go
index 8ca9ac3cf..3084e6593 100644
--- a/pkg/tcpip/stack/transport_test.go
+++ b/pkg/tcpip/stack/transport_test.go
@@ -56,6 +56,8 @@ func (f *fakeTransportEndpoint) Stats() tcpip.EndpointStats {
 	return nil
 }
 
+func (f *fakeTransportEndpoint) SetOwner(owner tcpip.PacketOwner) {}
+
 func newFakeTransportEndpoint(s *stack.Stack, proto *fakeTransportProtocol, netProto tcpip.NetworkProtocolNumber, uniqueID uint64) tcpip.Endpoint {
 	return &fakeTransportEndpoint{stack: s, TransportEndpointInfo: stack.TransportEndpointInfo{NetProto: netProto}, proto: proto, uniqueID: uniqueID}
 }