Add support for IP_RECVORIGDSTADDR IP option.

Fixes #5004

PiperOrigin-RevId: 346643745

3 files changed, 66 insertions, 12 deletions

diff --git a/pkg/sentry/socket/control/control.go b/pkg/sentry/socket/control/control.go
index 70ccf77a7..c284efde5 100644
--- a/pkg/sentry/socket/control/control.go
+++ b/pkg/sentry/socket/control/control.go
@@ -359,13 +359,26 @@ func PackIPPacketInfo(t *kernel.Task, packetInfo tcpip.IPPacketInfo, buf []byte)
 	)
 }
 
+// PackOriginalDstAddress packs an IP_RECVORIGINALDSTADDR socket control message.
+func PackOriginalDstAddress(t *kernel.Task, family int, originalDstAddress tcpip.FullAddress, buf []byte) []byte {
+	p, _ := socket.ConvertAddress(family, originalDstAddress)
+	level := uint32(linux.SOL_IP)
+	optType := uint32(linux.IP_RECVORIGDSTADDR)
+	if family == linux.AF_INET6 {
+		level = linux.SOL_IPV6
+		optType = linux.IPV6_RECVORIGDSTADDR
+	}
+	return putCmsgStruct(
+		buf, level, optType, t.Arch().Width(), p)
+}
+
 // PackControlMessages packs control messages into the given buffer.
 //
 // We skip control messages specific to Unix domain sockets.
 //
 // Note that some control messages may be truncated if they do not fit under
 // the capacity of buf.
-func PackControlMessages(t *kernel.Task, cmsgs socket.ControlMessages, buf []byte) []byte {
+func PackControlMessages(t *kernel.Task, family int, cmsgs socket.ControlMessages, buf []byte) []byte {
 	if cmsgs.IP.HasTimestamp {
 		buf = PackTimestamp(t, cmsgs.IP.Timestamp, buf)
 	}
@@ -387,6 +400,10 @@ func PackControlMessages(t *kernel.Task, cmsgs socket.ControlMessages, buf []byt
 		buf = PackIPPacketInfo(t, cmsgs.IP.PacketInfo, buf)
 	}
 
+	if cmsgs.IP.HasOriginalDstAddress {
+		buf = PackOriginalDstAddress(t, family, cmsgs.IP.OriginalDstAddress, buf)
+	}
+
 	return buf
 }
 
diff --git a/pkg/sentry/socket/hostinet/socket.go b/pkg/sentry/socket/hostinet/socket.go
index 7d3c4a01c..a35850a8f 100644
--- a/pkg/sentry/socket/hostinet/socket.go
+++ b/pkg/sentry/socket/hostinet/socket.go
@@ -551,7 +551,7 @@ func (s *socketOpsCommon) SendMsg(t *kernel.Task, src usermem.IOSequence, to []b
 	}
 	controlBuf := make([]byte, 0, space)
 	// PackControlMessages will append up to space bytes to controlBuf.
-	controlBuf = control.PackControlMessages(t, controlMessages, controlBuf)
+	controlBuf = control.PackControlMessages(t, s.family, controlMessages, controlBuf)
 
 	sendmsgFromBlocks := safemem.WriterFunc(func(srcs safemem.BlockSeq) (uint64, error) {
 		// Refuse to do anything if any part of src.Addrs was unusable.
diff --git a/pkg/sentry/socket/netstack/netstack.go b/pkg/sentry/socket/netstack/netstack.go
index 3cc0d4f0f..37c3faa57 100644
--- a/pkg/sentry/socket/netstack/netstack.go
+++ b/pkg/sentry/socket/netstack/netstack.go
@@ -1418,6 +1418,14 @@ func getSockOptIPv6(t *kernel.Task, s socket.SocketOps, ep commonEndpoint, name
 		v := primitive.Int32(boolToInt32(ep.SocketOptions().GetReceiveTClass()))
 		return &v, nil
 
+	case linux.IPV6_RECVORIGDSTADDR:
+		if outLen < sizeOfInt32 {
+			return nil, syserr.ErrInvalidArgument
+		}
+
+		v := primitive.Int32(boolToInt32(ep.SocketOptions().GetReceiveOriginalDstAddress()))
+		return &v, nil
+
 	case linux.IP6T_ORIGINAL_DST:
 		if outLen < int(binary.Size(linux.SockAddrInet6{})) {
 			return nil, syserr.ErrInvalidArgument
@@ -1599,6 +1607,14 @@ func getSockOptIP(t *kernel.Task, s socket.SocketOps, ep commonEndpoint, name in
 		v := primitive.Int32(boolToInt32(ep.SocketOptions().GetHeaderIncluded()))
 		return &v, nil
 
+	case linux.IP_RECVORIGDSTADDR:
+		if outLen < sizeOfInt32 {
+			return nil, syserr.ErrInvalidArgument
+		}
+
+		v := primitive.Int32(boolToInt32(ep.SocketOptions().GetReceiveOriginalDstAddress()))
+		return &v, nil
+
 	case linux.SO_ORIGINAL_DST:
 		if outLen < int(binary.Size(linux.SockAddrInet{})) {
 			return nil, syserr.ErrInvalidArgument
@@ -2094,6 +2110,15 @@ func setSockOptIPv6(t *kernel.Task, s socket.SocketOps, ep commonEndpoint, name
 
 		t.Kernel().EmitUnimplementedEvent(t)
 
+	case linux.IPV6_RECVORIGDSTADDR:
+		if len(optVal) < sizeOfInt32 {
+			return syserr.ErrInvalidArgument
+		}
+		v := int32(usermem.ByteOrder.Uint32(optVal))
+
+		ep.SocketOptions().SetReceiveOriginalDstAddress(v != 0)
+		return nil
+
 	case linux.IPV6_TCLASS:
 		if len(optVal) < sizeOfInt32 {
 			return syserr.ErrInvalidArgument
@@ -2325,6 +2350,18 @@ func setSockOptIP(t *kernel.Task, s socket.SocketOps, ep commonEndpoint, name in
 		ep.SocketOptions().SetHeaderIncluded(v != 0)
 		return nil
 
+	case linux.IP_RECVORIGDSTADDR:
+		if len(optVal) == 0 {
+			return nil
+		}
+		v, err := parseIntOrChar(optVal)
+		if err != nil {
+			return err
+		}
+
+		ep.SocketOptions().SetReceiveOriginalDstAddress(v != 0)
+		return nil
+
 	case linux.IPT_SO_SET_REPLACE:
 		if len(optVal) < linux.SizeOfIPTReplace {
 			return syserr.ErrInvalidArgument
@@ -2363,7 +2400,6 @@ func setSockOptIP(t *kernel.Task, s socket.SocketOps, ep commonEndpoint, name in
 		linux.IP_RECVERR,
 		linux.IP_RECVFRAGSIZE,
 		linux.IP_RECVOPTS,
-		linux.IP_RECVORIGDSTADDR,
 		linux.IP_RECVTTL,
 		linux.IP_RETOPTS,
 		linux.IP_TRANSPARENT,
@@ -2441,7 +2477,6 @@ func emitUnimplementedEventIPv6(t *kernel.Task, name int) {
 		linux.IPV6_RECVFRAGSIZE,
 		linux.IPV6_RECVHOPLIMIT,
 		linux.IPV6_RECVHOPOPTS,
-		linux.IPV6_RECVORIGDSTADDR,
 		linux.IPV6_RECVPATHMTU,
 		linux.IPV6_RECVPKTINFO,
 		linux.IPV6_RECVRTHDR,
@@ -2746,14 +2781,16 @@ func (s *socketOpsCommon) nonBlockingRead(ctx context.Context, dst usermem.IOSeq
 func (s *socketOpsCommon) controlMessages() socket.ControlMessages {
 	return socket.ControlMessages{
 		IP: tcpip.ControlMessages{
-			HasTimestamp:    s.readCM.HasTimestamp && s.sockOptTimestamp,
-			Timestamp:       s.readCM.Timestamp,
-			HasTOS:          s.readCM.HasTOS,
-			TOS:             s.readCM.TOS,
-			HasTClass:       s.readCM.HasTClass,
-			TClass:          s.readCM.TClass,
-			HasIPPacketInfo: s.readCM.HasIPPacketInfo,
-			PacketInfo:      s.readCM.PacketInfo,
+			HasTimestamp:          s.readCM.HasTimestamp && s.sockOptTimestamp,
+			Timestamp:             s.readCM.Timestamp,
+			HasTOS:                s.readCM.HasTOS,
+			TOS:                   s.readCM.TOS,
+			HasTClass:             s.readCM.HasTClass,
+			TClass:                s.readCM.TClass,
+			HasIPPacketInfo:       s.readCM.HasIPPacketInfo,
+			PacketInfo:            s.readCM.PacketInfo,
+			HasOriginalDstAddress: s.readCM.HasOriginalDstAddress,
+			OriginalDstAddress:    s.readCM.OriginalDstAddress,
 		},
 	}
 }