Merge release-20200127.0-80-g665b614 (automated)

10 files changed, 400 insertions, 104 deletions

diff --git a/pkg/sentry/inet/inet.go b/pkg/sentry/inet/inet.go
index a7dfb78a7..2916a0644 100644
--- a/pkg/sentry/inet/inet.go
+++ b/pkg/sentry/inet/inet.go
@@ -28,6 +28,10 @@ type Stack interface {
 	// interface indexes to a slice of associated interface address properties.
 	InterfaceAddrs() map[int32][]InterfaceAddr
 
+	// AddInterfaceAddr adds an address to the network interface identified by
+	// index.
+	AddInterfaceAddr(idx int32, addr InterfaceAddr) error
+
 	// SupportsIPv6 returns true if the stack supports IPv6 connectivity.
 	SupportsIPv6() bool
 
diff --git a/pkg/sentry/inet/test_stack.go b/pkg/sentry/inet/test_stack.go
index dcfcbd97e..d8961fc94 100644
--- a/pkg/sentry/inet/test_stack.go
+++ b/pkg/sentry/inet/test_stack.go
@@ -47,6 +47,12 @@ func (s *TestStack) InterfaceAddrs() map[int32][]InterfaceAddr {
 	return s.InterfaceAddrsMap
 }
 
+// AddInterfaceAddr implements Stack.AddInterfaceAddr.
+func (s *TestStack) AddInterfaceAddr(idx int32, addr InterfaceAddr) error {
+	s.InterfaceAddrsMap[idx] = append(s.InterfaceAddrsMap[idx], addr)
+	return nil
+}
+
 // SupportsIPv6 implements Stack.SupportsIPv6.
 func (s *TestStack) SupportsIPv6() bool {
 	return s.SupportsIPv6Flag
diff --git a/pkg/sentry/socket/hostinet/stack.go b/pkg/sentry/socket/hostinet/stack.go
index 034eca676..a48082631 100644
--- a/pkg/sentry/socket/hostinet/stack.go
+++ b/pkg/sentry/socket/hostinet/stack.go
@@ -310,6 +310,11 @@ func (s *Stack) InterfaceAddrs() map[int32][]inet.InterfaceAddr {
 	return addrs
 }
 
+// AddInterfaceAddr implements inet.Stack.AddInterfaceAddr.
+func (s *Stack) AddInterfaceAddr(idx int32, addr inet.InterfaceAddr) error {
+	return syserror.EACCES
+}
+
 // SupportsIPv6 implements inet.Stack.SupportsIPv6.
 func (s *Stack) SupportsIPv6() bool {
 	return s.supportsIPv6
diff --git a/pkg/sentry/socket/netlink/message.go b/pkg/sentry/socket/netlink/message.go
index b21e0ca4b..4ea252ccb 100644
--- a/pkg/sentry/socket/netlink/message.go
+++ b/pkg/sentry/socket/netlink/message.go
@@ -30,8 +30,16 @@ func alignUp(length int, align uint) int {
 	return (length + int(align) - 1) &^ (int(align) - 1)
 }
 
+// alignPad returns the length of padding required for alignment.
+//
+// Preconditions: align is a power of two.
+func alignPad(length int, align uint) int {
+	return alignUp(length, align) - length
+}
+
 // Message contains a complete serialized netlink message.
 type Message struct {
+	hdr linux.NetlinkMessageHeader
 	buf []byte
 }
 
@@ -40,10 +48,86 @@ type Message struct {
 // The header length will be updated by Finalize.
 func NewMessage(hdr linux.NetlinkMessageHeader) *Message {
 	return &Message{
+		hdr: hdr,
 		buf: binary.Marshal(nil, usermem.ByteOrder, hdr),
 	}
 }
 
+// ParseMessage parses the first message seen at buf, returning the rest of the
+// buffer. If message is malformed, ok of false is returned. For last message,
+// padding check is loose, if there isn't enought padding, whole buf is consumed
+// and ok is set to true.
+func ParseMessage(buf []byte) (msg *Message, rest []byte, ok bool) {
+	b := BytesView(buf)
+
+	hdrBytes, ok := b.Extract(linux.NetlinkMessageHeaderSize)
+	if !ok {
+		return
+	}
+	var hdr linux.NetlinkMessageHeader
+	binary.Unmarshal(hdrBytes, usermem.ByteOrder, &hdr)
+
+	// Msg portion.
+	totalMsgLen := int(hdr.Length)
+	_, ok = b.Extract(totalMsgLen - linux.NetlinkMessageHeaderSize)
+	if !ok {
+		return
+	}
+
+	// Padding.
+	numPad := alignPad(totalMsgLen, linux.NLMSG_ALIGNTO)
+	// Linux permits the last message not being aligned, just consume all of it.
+	// Ref: net/netlink/af_netlink.c:netlink_rcv_skb
+	if numPad > len(b) {
+		numPad = len(b)
+	}
+	_, ok = b.Extract(numPad)
+	if !ok {
+		return
+	}
+
+	return &Message{
+		hdr: hdr,
+		buf: buf[:totalMsgLen],
+	}, []byte(b), true
+}
+
+// Header returns the header of this message.
+func (m *Message) Header() linux.NetlinkMessageHeader {
+	return m.hdr
+}
+
+// GetData unmarshals the payload message header from this netlink message, and
+// returns the attributes portion.
+func (m *Message) GetData(msg interface{}) (AttrsView, bool) {
+	b := BytesView(m.buf)
+
+	_, ok := b.Extract(linux.NetlinkMessageHeaderSize)
+	if !ok {
+		return nil, false
+	}
+
+	size := int(binary.Size(msg))
+	msgBytes, ok := b.Extract(size)
+	if !ok {
+		return nil, false
+	}
+	binary.Unmarshal(msgBytes, usermem.ByteOrder, msg)
+
+	numPad := alignPad(linux.NetlinkMessageHeaderSize+size, linux.NLMSG_ALIGNTO)
+	// Linux permits the last message not being aligned, just consume all of it.
+	// Ref: net/netlink/af_netlink.c:netlink_rcv_skb
+	if numPad > len(b) {
+		numPad = len(b)
+	}
+	_, ok = b.Extract(numPad)
+	if !ok {
+		return nil, false
+	}
+
+	return AttrsView(b), true
+}
+
 // Finalize returns the []byte containing the entire message, with the total
 // length set in the message header. The Message must not be modified after
 // calling Finalize.
@@ -157,3 +241,48 @@ func (ms *MessageSet) AddMessage(hdr linux.NetlinkMessageHeader) *Message {
 	ms.Messages = append(ms.Messages, m)
 	return m
 }
+
+// AttrsView is a view into the attributes portion of a netlink message.
+type AttrsView []byte
+
+// Empty returns whether there is no attribute left in v.
+func (v AttrsView) Empty() bool {
+	return len(v) == 0
+}
+
+// ParseFirst parses first netlink attribute at the beginning of v.
+func (v AttrsView) ParseFirst() (hdr linux.NetlinkAttrHeader, value []byte, rest AttrsView, ok bool) {
+	b := BytesView(v)
+
+	hdrBytes, ok := b.Extract(linux.NetlinkAttrHeaderSize)
+	if !ok {
+		return
+	}
+	binary.Unmarshal(hdrBytes, usermem.ByteOrder, &hdr)
+
+	value, ok = b.Extract(int(hdr.Length) - linux.NetlinkAttrHeaderSize)
+	if !ok {
+		return
+	}
+
+	_, ok = b.Extract(alignPad(int(hdr.Length), linux.NLA_ALIGNTO))
+	if !ok {
+		return
+	}
+
+	return hdr, value, AttrsView(b), ok
+}
+
+// BytesView supports extracting data from a byte slice with bounds checking.
+type BytesView []byte
+
+// Extract removes the first n bytes from v and returns it. If n is out of
+// bounds, it returns false.
+func (v *BytesView) Extract(n int) ([]byte, bool) {
+	if n < 0 || n > len(*v) {
+		return nil, false
+	}
+	extracted := (*v)[:n]
+	*v = (*v)[n:]
+	return extracted, true
+}
diff --git a/pkg/sentry/socket/netlink/provider.go b/pkg/sentry/socket/netlink/provider.go
index 07f860a49..b0dc70e5c 100644
--- a/pkg/sentry/socket/netlink/provider.go
+++ b/pkg/sentry/socket/netlink/provider.go
@@ -42,7 +42,7 @@ type Protocol interface {
 	// If err == nil, any messages added to ms will be sent back to the
 	// other end of the socket. Setting ms.Multi will cause an NLMSG_DONE
 	// message to be sent even if ms contains no messages.
-	ProcessMessage(ctx context.Context, hdr linux.NetlinkMessageHeader, data []byte, ms *MessageSet) *syserr.Error
+	ProcessMessage(ctx context.Context, msg *Message, ms *MessageSet) *syserr.Error
 }
 
 // Provider is a function that creates a new Protocol for a specific netlink
diff --git a/pkg/sentry/socket/netlink/route/protocol.go b/pkg/sentry/socket/netlink/route/protocol.go
index 2b3c7f5b3..c84d8bd7c 100644
--- a/pkg/sentry/socket/netlink/route/protocol.go
+++ b/pkg/sentry/socket/netlink/route/protocol.go
@@ -17,16 +17,15 @@ package route
 
 import (
 	"bytes"
+	"syscall"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
-	"gvisor.dev/gvisor/pkg/binary"
 	"gvisor.dev/gvisor/pkg/context"
 	"gvisor.dev/gvisor/pkg/sentry/inet"
 	"gvisor.dev/gvisor/pkg/sentry/kernel"
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
 	"gvisor.dev/gvisor/pkg/sentry/socket/netlink"
 	"gvisor.dev/gvisor/pkg/syserr"
-	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 // commandKind describes the operational class of a message type.
@@ -69,13 +68,7 @@ func (p *Protocol) CanSend() bool {
 }
 
 // dumpLinks handles RTM_GETLINK dump requests.
-func (p *Protocol) dumpLinks(ctx context.Context, hdr linux.NetlinkMessageHeader, data []byte, ms *netlink.MessageSet) *syserr.Error {
-	// TODO(b/68878065): Only the dump variant of the types below are
-	// supported.
-	if hdr.Flags&linux.NLM_F_DUMP != linux.NLM_F_DUMP {
-		return syserr.ErrNotSupported
-	}
-
+func (p *Protocol) dumpLinks(ctx context.Context, msg *netlink.Message, ms *netlink.MessageSet) *syserr.Error {
 	// NLM_F_DUMP + RTM_GETLINK messages are supposed to include an
 	// ifinfomsg. However, Linux <3.9 only checked for rtgenmsg, and some
 	// userspace applications (including glibc) still include rtgenmsg.
@@ -99,44 +92,105 @@ func (p *Protocol) dumpLinks(ctx context.Context, hdr linux.NetlinkMessageHeader
 		return nil
 	}
 
-	for id, i := range stack.Interfaces() {
-		m := ms.AddMessage(linux.NetlinkMessageHeader{
-			Type: linux.RTM_NEWLINK,
-		})
+	for idx, i := range stack.Interfaces() {
+		addNewLinkMessage(ms, idx, i)
+	}
 
-		m.Put(linux.InterfaceInfoMessage{
-			Family: linux.AF_UNSPEC,
-			Type:   i.DeviceType,
-			Index:  id,
-			Flags:  i.Flags,
-		})
+	return nil
+}
 
-		m.PutAttrString(linux.IFLA_IFNAME, i.Name)
-		m.PutAttr(linux.IFLA_MTU, i.MTU)
+// getLinks handles RTM_GETLINK requests.
+func (p *Protocol) getLink(ctx context.Context, msg *netlink.Message, ms *netlink.MessageSet) *syserr.Error {
+	stack := inet.StackFromContext(ctx)
+	if stack == nil {
+		// No network devices.
+		return nil
+	}
 
-		mac := make([]byte, 6)
-		brd := mac
-		if len(i.Addr) > 0 {
-			mac = i.Addr
-			brd = bytes.Repeat([]byte{0xff}, len(i.Addr))
+	// Parse message.
+	var ifi linux.InterfaceInfoMessage
+	attrs, ok := msg.GetData(&ifi)
+	if !ok {
+		return syserr.ErrInvalidArgument
+	}
+
+	// Parse attributes.
+	var byName []byte
+	for !attrs.Empty() {
+		ahdr, value, rest, ok := attrs.ParseFirst()
+		if !ok {
+			return syserr.ErrInvalidArgument
 		}
-		m.PutAttr(linux.IFLA_ADDRESS, mac)
-		m.PutAttr(linux.IFLA_BROADCAST, brd)
+		attrs = rest
 
-		// TODO(gvisor.dev/issue/578): There are many more attributes.
+		switch ahdr.Type {
+		case linux.IFLA_IFNAME:
+			if len(value) < 1 {
+				return syserr.ErrInvalidArgument
+			}
+			byName = value[:len(value)-1]
+
+			// TODO(gvisor.dev/issue/578): Support IFLA_EXT_MASK.
+		}
 	}
 
+	found := false
+	for idx, i := range stack.Interfaces() {
+		switch {
+		case ifi.Index > 0:
+			if idx != ifi.Index {
+				continue
+			}
+		case byName != nil:
+			if string(byName) != i.Name {
+				continue
+			}
+		default:
+			// Criteria not specified.
+			return syserr.ErrInvalidArgument
+		}
+
+		addNewLinkMessage(ms, idx, i)
+		found = true
+		break
+	}
+	if !found {
+		return syserr.ErrNoDevice
+	}
 	return nil
 }
 
-// dumpAddrs handles RTM_GETADDR dump requests.
-func (p *Protocol) dumpAddrs(ctx context.Context, hdr linux.NetlinkMessageHeader, data []byte, ms *netlink.MessageSet) *syserr.Error {
-	// TODO(b/68878065): Only the dump variant of the types below are
-	// supported.
-	if hdr.Flags&linux.NLM_F_DUMP != linux.NLM_F_DUMP {
-		return syserr.ErrNotSupported
+// addNewLinkMessage appends RTM_NEWLINK message for the given interface into
+// the message set.
+func addNewLinkMessage(ms *netlink.MessageSet, idx int32, i inet.Interface) {
+	m := ms.AddMessage(linux.NetlinkMessageHeader{
+		Type: linux.RTM_NEWLINK,
+	})
+
+	m.Put(linux.InterfaceInfoMessage{
+		Family: linux.AF_UNSPEC,
+		Type:   i.DeviceType,
+		Index:  idx,
+		Flags:  i.Flags,
+	})
+
+	m.PutAttrString(linux.IFLA_IFNAME, i.Name)
+	m.PutAttr(linux.IFLA_MTU, i.MTU)
+
+	mac := make([]byte, 6)
+	brd := mac
+	if len(i.Addr) > 0 {
+		mac = i.Addr
+		brd = bytes.Repeat([]byte{0xff}, len(i.Addr))
 	}
+	m.PutAttr(linux.IFLA_ADDRESS, mac)
+	m.PutAttr(linux.IFLA_BROADCAST, brd)
+
+	// TODO(gvisor.dev/issue/578): There are many more attributes.
+}
 
+// dumpAddrs handles RTM_GETADDR dump requests.
+func (p *Protocol) dumpAddrs(ctx context.Context, msg *netlink.Message, ms *netlink.MessageSet) *syserr.Error {
 	// RTM_GETADDR dump requests need not contain anything more than the
 	// netlink header and 1 byte protocol family common to all
 	// NETLINK_ROUTE requests.
@@ -168,6 +222,7 @@ func (p *Protocol) dumpAddrs(ctx context.Context, hdr linux.NetlinkMessageHeader
 				Index:     uint32(id),
 			})
 
+			m.PutAttr(linux.IFA_LOCAL, []byte(a.Addr))
 			m.PutAttr(linux.IFA_ADDRESS, []byte(a.Addr))
 
 			// TODO(gvisor.dev/issue/578): There are many more attributes.
@@ -252,12 +307,12 @@ func fillRoute(routes []inet.Route, addr []byte) (inet.Route, *syserr.Error) {
 }
 
 // parseForDestination parses a message as format of RouteMessage-RtAttr-dst.
-func parseForDestination(data []byte) ([]byte, *syserr.Error) {
+func parseForDestination(msg *netlink.Message) ([]byte, *syserr.Error) {
 	var rtMsg linux.RouteMessage
-	if len(data) < linux.SizeOfRouteMessage {
+	attrs, ok := msg.GetData(&rtMsg)
+	if !ok {
 		return nil, syserr.ErrInvalidArgument
 	}
-	binary.Unmarshal(data[:linux.SizeOfRouteMessage], usermem.ByteOrder, &rtMsg)
 	// iproute2 added the RTM_F_LOOKUP_TABLE flag in version v4.4.0. See
 	// commit bc234301af12. Note we don't check this flag for backward
 	// compatibility.
@@ -265,26 +320,15 @@ func parseForDestination(data []byte) ([]byte, *syserr.Error) {
 		return nil, syserr.ErrNotSupported
 	}
 
-	data = data[linux.SizeOfRouteMessage:]
-
-	// TODO(gvisor.dev/issue/1611): Add generic attribute parsing.
-	var rtAttr linux.RtAttr
-	if len(data) < linux.SizeOfRtAttr {
-		return nil, syserr.ErrInvalidArgument
+	// Expect first attribute is RTA_DST.
+	if hdr, value, _, ok := attrs.ParseFirst(); ok && hdr.Type == linux.RTA_DST {
+		return value, nil
 	}
-	binary.Unmarshal(data[:linux.SizeOfRtAttr], usermem.ByteOrder, &rtAttr)
-	if rtAttr.Type != linux.RTA_DST {
-		return nil, syserr.ErrInvalidArgument
-	}
-
-	if len(data) < int(rtAttr.Len) {
-		return nil, syserr.ErrInvalidArgument
-	}
-	return data[linux.SizeOfRtAttr:rtAttr.Len], nil
+	return nil, syserr.ErrInvalidArgument
 }
 
 // dumpRoutes handles RTM_GETROUTE requests.
-func (p *Protocol) dumpRoutes(ctx context.Context, hdr linux.NetlinkMessageHeader, data []byte, ms *netlink.MessageSet) *syserr.Error {
+func (p *Protocol) dumpRoutes(ctx context.Context, msg *netlink.Message, ms *netlink.MessageSet) *syserr.Error {
 	// RTM_GETROUTE dump requests need not contain anything more than the
 	// netlink header and 1 byte protocol family common to all
 	// NETLINK_ROUTE requests.
@@ -295,10 +339,11 @@ func (p *Protocol) dumpRoutes(ctx context.Context, hdr linux.NetlinkMessageHeade
 		return nil
 	}
 
+	hdr := msg.Header()
 	routeTables := stack.RouteTable()
 
 	if hdr.Flags == linux.NLM_F_REQUEST {
-		dst, err := parseForDestination(data)
+		dst, err := parseForDestination(msg)
 		if err != nil {
 			return err
 		}
@@ -357,10 +402,55 @@ func (p *Protocol) dumpRoutes(ctx context.Context, hdr linux.NetlinkMessageHeade
 	return nil
 }
 
+// newAddr handles RTM_NEWADDR requests.
+func (p *Protocol) newAddr(ctx context.Context, msg *netlink.Message, ms *netlink.MessageSet) *syserr.Error {
+	stack := inet.StackFromContext(ctx)
+	if stack == nil {
+		// No network stack.
+		return syserr.ErrProtocolNotSupported
+	}
+
+	var ifa linux.InterfaceAddrMessage
+	attrs, ok := msg.GetData(&ifa)
+	if !ok {
+		return syserr.ErrInvalidArgument
+	}
+
+	for !attrs.Empty() {
+		ahdr, value, rest, ok := attrs.ParseFirst()
+		if !ok {
+			return syserr.ErrInvalidArgument
+		}
+		attrs = rest
+
+		switch ahdr.Type {
+		case linux.IFA_LOCAL:
+			err := stack.AddInterfaceAddr(int32(ifa.Index), inet.InterfaceAddr{
+				Family:    ifa.Family,
+				PrefixLen: ifa.PrefixLen,
+				Flags:     ifa.Flags,
+				Addr:      value,
+			})
+			if err == syscall.EEXIST {
+				flags := msg.Header().Flags
+				if flags&linux.NLM_F_EXCL != 0 {
+					return syserr.ErrExists
+				}
+			} else if err != nil {
+				return syserr.ErrInvalidArgument
+			}
+		}
+	}
+	return nil
+}
+
 // ProcessMessage implements netlink.Protocol.ProcessMessage.
-func (p *Protocol) ProcessMessage(ctx context.Context, hdr linux.NetlinkMessageHeader, data []byte, ms *netlink.MessageSet) *syserr.Error {
+func (p *Protocol) ProcessMessage(ctx context.Context, msg *netlink.Message, ms *netlink.MessageSet) *syserr.Error {
+	hdr := msg.Header()
+
 	// All messages start with a 1 byte protocol family.
-	if len(data) < 1 {
+	var family uint8
+	if _, ok := msg.GetData(&family); !ok {
 		// Linux ignores messages missing the protocol family. See
 		// net/core/rtnetlink.c:rtnetlink_rcv_msg.
 		return nil
@@ -374,16 +464,32 @@ func (p *Protocol) ProcessMessage(ctx context.Context, hdr linux.NetlinkMessageH
 		}
 	}
 
-	switch hdr.Type {
-	case linux.RTM_GETLINK:
-		return p.dumpLinks(ctx, hdr, data, ms)
-	case linux.RTM_GETADDR:
-		return p.dumpAddrs(ctx, hdr, data, ms)
-	case linux.RTM_GETROUTE:
-		return p.dumpRoutes(ctx, hdr, data, ms)
-	default:
-		return syserr.ErrNotSupported
+	if hdr.Flags&linux.NLM_F_DUMP == linux.NLM_F_DUMP {
+		// TODO(b/68878065): Only the dump variant of the types below are
+		// supported.
+		switch hdr.Type {
+		case linux.RTM_GETLINK:
+			return p.dumpLinks(ctx, msg, ms)
+		case linux.RTM_GETADDR:
+			return p.dumpAddrs(ctx, msg, ms)
+		case linux.RTM_GETROUTE:
+			return p.dumpRoutes(ctx, msg, ms)
+		default:
+			return syserr.ErrNotSupported
+		}
+	} else if hdr.Flags&linux.NLM_F_REQUEST == linux.NLM_F_REQUEST {
+		switch hdr.Type {
+		case linux.RTM_GETLINK:
+			return p.getLink(ctx, msg, ms)
+		case linux.RTM_GETROUTE:
+			return p.dumpRoutes(ctx, msg, ms)
+		case linux.RTM_NEWADDR:
+			return p.newAddr(ctx, msg, ms)
+		default:
+			return syserr.ErrNotSupported
+		}
 	}
+	return syserr.ErrNotSupported
 }
 
 // init registers the NETLINK_ROUTE provider.
diff --git a/pkg/sentry/socket/netlink/socket.go b/pkg/sentry/socket/netlink/socket.go
index c4b95debb..2ca02567d 100644
--- a/pkg/sentry/socket/netlink/socket.go
+++ b/pkg/sentry/socket/netlink/socket.go
@@ -644,47 +644,38 @@ func (s *Socket) sendResponse(ctx context.Context, ms *MessageSet) *syserr.Error
 	return nil
 }
 
-func (s *Socket) dumpErrorMesage(ctx context.Context, hdr linux.NetlinkMessageHeader, ms *MessageSet, err *syserr.Error) *syserr.Error {
+func dumpErrorMesage(hdr linux.NetlinkMessageHeader, ms *MessageSet, err *syserr.Error) {
 	m := ms.AddMessage(linux.NetlinkMessageHeader{
 		Type: linux.NLMSG_ERROR,
 	})
-
 	m.Put(linux.NetlinkErrorMessage{
 		Error:  int32(-err.ToLinux().Number()),
 		Header: hdr,
 	})
-	return nil
+}
 
+func dumpAckMesage(hdr linux.NetlinkMessageHeader, ms *MessageSet) {
+	m := ms.AddMessage(linux.NetlinkMessageHeader{
+		Type: linux.NLMSG_ERROR,
+	})
+	m.Put(linux.NetlinkErrorMessage{
+		Error:  0,
+		Header: hdr,
+	})
 }
 
 // processMessages handles each message in buf, passing it to the protocol
 // handler for final handling.
 func (s *Socket) processMessages(ctx context.Context, buf []byte) *syserr.Error {
 	for len(buf) > 0 {
-		if len(buf) < linux.NetlinkMessageHeaderSize {
+		msg, rest, ok := ParseMessage(buf)
+		if !ok {
 			// Linux ignores messages that are too short. See
 			// net/netlink/af_netlink.c:netlink_rcv_skb.
 			break
 		}
-
-		var hdr linux.NetlinkMessageHeader
-		binary.Unmarshal(buf[:linux.NetlinkMessageHeaderSize], usermem.ByteOrder, &hdr)
-
-		if hdr.Length < linux.NetlinkMessageHeaderSize || uint64(hdr.Length) > uint64(len(buf)) {
-			// Linux ignores malformed messages. See
-			// net/netlink/af_netlink.c:netlink_rcv_skb.
-			break
-		}
-
-		// Data from this message.
-		data := buf[linux.NetlinkMessageHeaderSize:hdr.Length]
-
-		// Advance to the next message.
-		next := alignUp(int(hdr.Length), linux.NLMSG_ALIGNTO)
-		if next >= len(buf)-1 {
-			next = len(buf) - 1
-		}
-		buf = buf[next:]
+		buf = rest
+		hdr := msg.Header()
 
 		// Ignore control messages.
 		if hdr.Type < linux.NLMSG_MIN_TYPE {
@@ -692,19 +683,10 @@ func (s *Socket) processMessages(ctx context.Context, buf []byte) *syserr.Error
 		}
 
 		ms := NewMessageSet(s.portID, hdr.Seq)
-		var err *syserr.Error
-		// TODO(b/68877377): ACKs not supported yet.
-		if hdr.Flags&linux.NLM_F_ACK == linux.NLM_F_ACK {
-			err = syserr.ErrNotSupported
-		} else {
-
-			err = s.protocol.ProcessMessage(ctx, hdr, data, ms)
-		}
-		if err != nil {
-			ms = NewMessageSet(s.portID, hdr.Seq)
-			if err := s.dumpErrorMesage(ctx, hdr, ms, err); err != nil {
-				return err
-			}
+		if err := s.protocol.ProcessMessage(ctx, msg, ms); err != nil {
+			dumpErrorMesage(hdr, ms, err)
+		} else if hdr.Flags&linux.NLM_F_ACK == linux.NLM_F_ACK {
+			dumpAckMesage(hdr, ms)
 		}
 
 		if err := s.sendResponse(ctx, ms); err != nil {
diff --git a/pkg/sentry/socket/netlink/uevent/protocol.go b/pkg/sentry/socket/netlink/uevent/protocol.go
index 1ee4296bc..029ba21b5 100755
--- a/pkg/sentry/socket/netlink/uevent/protocol.go
+++ b/pkg/sentry/socket/netlink/uevent/protocol.go
@@ -49,7 +49,7 @@ func (p *Protocol) CanSend() bool {
 }
 
 // ProcessMessage implements netlink.Protocol.ProcessMessage.
-func (p *Protocol) ProcessMessage(ctx context.Context, hdr linux.NetlinkMessageHeader, data []byte, ms *netlink.MessageSet) *syserr.Error {
+func (p *Protocol) ProcessMessage(ctx context.Context, msg *netlink.Message, ms *netlink.MessageSet) *syserr.Error {
 	// Silently ignore all messages.
 	return nil
 }
diff --git a/pkg/sentry/socket/netstack/stack.go b/pkg/sentry/socket/netstack/stack.go
index 31ea66eca..0692482e9 100755
--- a/pkg/sentry/socket/netstack/stack.go
+++ b/pkg/sentry/socket/netstack/stack.go
@@ -20,6 +20,8 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/inet"
 	"gvisor.dev/gvisor/pkg/sentry/socket/netfilter"
 	"gvisor.dev/gvisor/pkg/syserr"
+	"gvisor.dev/gvisor/pkg/syserror"
+	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/header"
 	"gvisor.dev/gvisor/pkg/tcpip/iptables"
 	"gvisor.dev/gvisor/pkg/tcpip/network/ipv4"
@@ -88,6 +90,59 @@ func (s *Stack) InterfaceAddrs() map[int32][]inet.InterfaceAddr {
 	return nicAddrs
 }
 
+// AddInterfaceAddr implements inet.Stack.AddInterfaceAddr.
+func (s *Stack) AddInterfaceAddr(idx int32, addr inet.InterfaceAddr) error {
+	var (
+		protocol tcpip.NetworkProtocolNumber
+		address  tcpip.Address
+	)
+	switch addr.Family {
+	case linux.AF_INET:
+		if len(addr.Addr) < header.IPv4AddressSize {
+			return syserror.EINVAL
+		}
+		if addr.PrefixLen > header.IPv4AddressSize*8 {
+			return syserror.EINVAL
+		}
+		protocol = ipv4.ProtocolNumber
+		address = tcpip.Address(addr.Addr[:header.IPv4AddressSize])
+
+	case linux.AF_INET6:
+		if len(addr.Addr) < header.IPv6AddressSize {
+			return syserror.EINVAL
+		}
+		if addr.PrefixLen > header.IPv6AddressSize*8 {
+			return syserror.EINVAL
+		}
+		protocol = ipv6.ProtocolNumber
+		address = tcpip.Address(addr.Addr[:header.IPv6AddressSize])
+
+	default:
+		return syserror.ENOTSUP
+	}
+
+	protocolAddress := tcpip.ProtocolAddress{
+		Protocol: protocol,
+		AddressWithPrefix: tcpip.AddressWithPrefix{
+			Address:   address,
+			PrefixLen: int(addr.PrefixLen),
+		},
+	}
+
+	// Attach address to interface.
+	if err := s.Stack.AddProtocolAddressWithOptions(tcpip.NICID(idx), protocolAddress, stack.CanBePrimaryEndpoint); err != nil {
+		return syserr.TranslateNetstackError(err).ToError()
+	}
+
+	// Add route for local network.
+	s.Stack.AddRoute(tcpip.Route{
+		Destination: protocolAddress.AddressWithPrefix.Subnet(),
+		Gateway:     "", // No gateway for local network.
+		NIC:         tcpip.NICID(idx),
+	})
+	return nil
+}
+
 // TCPReceiveBufferSize implements inet.Stack.TCPReceiveBufferSize.
 func (s *Stack) TCPReceiveBufferSize() (inet.TCPBufferSize, error) {
 	var rs tcp.ReceiveBufferSizeOption
diff --git a/pkg/tcpip/stack/stack.go b/pkg/tcpip/stack/stack.go
index 7057b110e..b793f1d74 100644
--- a/pkg/tcpip/stack/stack.go
+++ b/pkg/tcpip/stack/stack.go
@@ -795,6 +795,8 @@ func (s *Stack) Forwarding() bool {
 
 // SetRouteTable assigns the route table to be used by this stack. It
 // specifies which NIC to use for given destination address ranges.
+//
+// This method takes ownership of the table.
 func (s *Stack) SetRouteTable(table []tcpip.Route) {
 	s.mu.Lock()
 	defer s.mu.Unlock()
@@ -809,6 +811,13 @@ func (s *Stack) GetRouteTable() []tcpip.Route {
 	return append([]tcpip.Route(nil), s.routeTable...)
 }
 
+// AddRoute appends a route to the route table.
+func (s *Stack) AddRoute(route tcpip.Route) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	s.routeTable = append(s.routeTable, route)
+}
+
 // NewEndpoint creates a new transport layer endpoint of the given protocol.
 func (s *Stack) NewEndpoint(transport tcpip.TransportProtocolNumber, network tcpip.NetworkProtocolNumber, waiterQueue *waiter.Queue) (tcpip.Endpoint, *tcpip.Error) {
 	t, ok := s.transportProtocols[transport]