Merge pull request #2275 from nybidari:iptables

PiperOrigin-RevId: 309783486

4 files changed, 44 insertions, 7 deletions

diff --git a/pkg/sentry/socket/netfilter/netfilter.go b/pkg/sentry/socket/netfilter/netfilter.go
index 72d093aa8..40736fb38 100644
--- a/pkg/sentry/socket/netfilter/netfilter.go
+++ b/pkg/sentry/socket/netfilter/netfilter.go
@@ -251,7 +251,7 @@ func marshalTarget(target stack.Target) []byte {
 	case stack.ReturnTarget:
 		return marshalStandardTarget(stack.RuleReturn)
 	case stack.RedirectTarget:
-		return marshalRedirectTarget()
+		return marshalRedirectTarget(tg)
 	case JumpTarget:
 		return marshalJumpTarget(tg)
 	default:
@@ -288,7 +288,7 @@ func marshalErrorTarget(errorName string) []byte {
 	return binary.Marshal(ret, usermem.ByteOrder, target)
 }
 
-func marshalRedirectTarget() []byte {
+func marshalRedirectTarget(rt stack.RedirectTarget) []byte {
 	// This is a redirect target named redirect
 	target := linux.XTRedirectTarget{
 		Target: linux.XTEntryTarget{
@@ -298,6 +298,16 @@ func marshalRedirectTarget() []byte {
 	copy(target.Target.Name[:], redirectTargetName)
 
 	ret := make([]byte, 0, linux.SizeOfXTRedirectTarget)
+	target.NfRange.RangeSize = 1
+	if rt.RangeProtoSpecified {
+		target.NfRange.RangeIPV4.Flags |= linux.NF_NAT_RANGE_PROTO_SPECIFIED
+	}
+	// Convert port from little endian to big endian.
+	port := make([]byte, 2)
+	binary.LittleEndian.PutUint16(port, rt.MinPort)
+	target.NfRange.RangeIPV4.MinPort = binary.BigEndian.Uint16(port)
+	binary.LittleEndian.PutUint16(port, rt.MaxPort)
+	target.NfRange.RangeIPV4.MaxPort = binary.BigEndian.Uint16(port)
 	return binary.Marshal(ret, usermem.ByteOrder, target)
 }
 
diff --git a/pkg/sentry/socket/netfilter/targets.go b/pkg/sentry/socket/netfilter/targets.go
index c948de876..84abe8d29 100644
--- a/pkg/sentry/socket/netfilter/targets.go
+++ b/pkg/sentry/socket/netfilter/targets.go
@@ -15,6 +15,7 @@
 package netfilter
 
 import (
+	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/stack"
 )
 
@@ -29,6 +30,6 @@ type JumpTarget struct {
 }
 
 // Action implements stack.Target.Action.
-func (jt JumpTarget) Action(stack.PacketBuffer) (stack.RuleVerdict, int) {
+func (jt JumpTarget) Action(*stack.PacketBuffer, *stack.ConnTrackTable, stack.Hook, *stack.GSO, *stack.Route, tcpip.Address) (stack.RuleVerdict, int) {
 	return stack.RuleJump, jt.RuleNum
 }
diff --git a/pkg/sentry/socket/netfilter/tcp_matcher.go b/pkg/sentry/socket/netfilter/tcp_matcher.go
index 55c0f04f3..57a1e1c12 100644
--- a/pkg/sentry/socket/netfilter/tcp_matcher.go
+++ b/pkg/sentry/socket/netfilter/tcp_matcher.go
@@ -120,14 +120,27 @@ func (tm *TCPMatcher) Match(hook stack.Hook, pkt stack.PacketBuffer, interfaceNa
 	if pkt.TransportHeader != nil {
 		tcpHeader = header.TCP(pkt.TransportHeader)
 	} else {
+		var length int
+		if hook == stack.Prerouting {
+			// The network header hasn't been parsed yet. We have to do it here.
+			hdr, ok := pkt.Data.PullUp(header.IPv4MinimumSize)
+			if !ok {
+				// There's no valid TCP header here, so we hotdrop the
+				// packet.
+				return false, true
+			}
+			h := header.IPv4(hdr)
+			pkt.NetworkHeader = hdr
+			length = int(h.HeaderLength())
+		}
 		// The TCP header hasn't been parsed yet. We have to do it here.
-		hdr, ok := pkt.Data.PullUp(header.TCPMinimumSize)
+		hdr, ok := pkt.Data.PullUp(length + header.TCPMinimumSize)
 		if !ok {
 			// There's no valid TCP header here, so we hotdrop the
 			// packet.
 			return false, true
 		}
-		tcpHeader = header.TCP(hdr)
+		tcpHeader = header.TCP(hdr[length:])
 	}
 
 	// Check whether the source and destination ports are within the
diff --git a/pkg/sentry/socket/netfilter/udp_matcher.go b/pkg/sentry/socket/netfilter/udp_matcher.go
index 04d03d494..cfa9e621d 100644
--- a/pkg/sentry/socket/netfilter/udp_matcher.go
+++ b/pkg/sentry/socket/netfilter/udp_matcher.go
@@ -119,14 +119,27 @@ func (um *UDPMatcher) Match(hook stack.Hook, pkt stack.PacketBuffer, interfaceNa
 	if pkt.TransportHeader != nil {
 		udpHeader = header.UDP(pkt.TransportHeader)
 	} else {
+		var length int
+		if hook == stack.Prerouting {
+			// The network header hasn't been parsed yet. We have to do it here.
+			hdr, ok := pkt.Data.PullUp(header.IPv4MinimumSize)
+			if !ok {
+				// There's no valid UDP header here, so we hotdrop the
+				// packet.
+				return false, true
+			}
+			h := header.IPv4(hdr)
+			pkt.NetworkHeader = hdr
+			length = int(h.HeaderLength())
+		}
 		// The UDP header hasn't been parsed yet. We have to do it here.
-		hdr, ok := pkt.Data.PullUp(header.UDPMinimumSize)
+		hdr, ok := pkt.Data.PullUp(length + header.UDPMinimumSize)
 		if !ok {
 			// There's no valid UDP header here, so we hotdrop the
 			// packet.
 			return false, true
 		}
-		udpHeader = header.UDP(hdr)
+		udpHeader = header.UDP(hdr[length:])
 	}
 
 	// Check whether the source and destination ports are within the