From cd3efc65190abffcaf02a6aeb5cd6489c797a245 Mon Sep 17 00:00:00 2001
From: Jing Chen <chjing@google.com>
Date: Fri, 21 Jun 2024 23:52:33 -0700
Subject: [PATCH] Support IFLA_ADDRESS which changes a device's hardware
 address.

PiperOrigin-RevId: 645611089
---
 pkg/sentry/socket/netstack/stack.go | 26 +++++++++++++++++++-------
 pkg/tcpip/stack/stack.go            | 13 +++++++++++++
 2 files changed, 32 insertions(+), 7 deletions(-)

diff --git a/pkg/sentry/socket/netstack/stack.go b/pkg/sentry/socket/netstack/stack.go
index ddf238e5f..3f9f15571 100644
--- a/pkg/sentry/socket/netstack/stack.go
+++ b/pkg/sentry/socket/netstack/stack.go
@@ -136,6 +136,7 @@ func (s *Stack) SetInterface(ctx context.Context, msg *nlmsg.Message) *syserr.Er
 			}
 		case linux.IFLA_MASTER:
 		case linux.IFLA_LINKINFO:
+		case linux.IFLA_ADDRESS:
 		default:
 			ctx.Warningf("unexpected attribute: %x", attr)
 			return syserr.ErrNotSupported
@@ -169,13 +170,24 @@ func (s *Stack) SetInterface(ctx context.Context, msg *nlmsg.Message) *syserr.Er
 }
 
 func (s *Stack) setLink(id tcpip.NICID, linkAttrs map[uint16]nlmsg.BytesView) *syserr.Error {
-	if v, ok := linkAttrs[linux.IFLA_MASTER]; ok {
-		master, ok := v.Uint32()
-		if !ok {
-			return syserr.ErrInvalidArgument
-		}
-		if master != 0 {
-			if err := s.Stack.SetNICCoordinator(id, tcpip.NICID(master)); err != nil {
+	for t, v := range linkAttrs {
+		switch t {
+		case linux.IFLA_MASTER:
+			master, ok := v.Uint32()
+			if !ok {
+				return syserr.ErrInvalidArgument
+			}
+			if master != 0 {
+				if err := s.Stack.SetNICCoordinator(id, tcpip.NICID(master)); err != nil {
+					return syserr.TranslateNetstackError(err)
+				}
+			}
+		case linux.IFLA_ADDRESS:
+			addr, err := tcpip.ParseMACAddress(v.String())
+			if err != nil {
+				return syserr.ErrInvalidArgument
+			}
+			if err := s.Stack.SetNICAddress(id, addr); err != nil {
 				return syserr.TranslateNetstackError(err)
 			}
 		}
diff --git a/pkg/tcpip/stack/stack.go b/pkg/tcpip/stack/stack.go
index 824a691cd..0b2bf516e 100644
--- a/pkg/tcpip/stack/stack.go
+++ b/pkg/tcpip/stack/stack.go
@@ -1025,6 +1025,19 @@ func (s *Stack) SetNICCoordinator(id tcpip.NICID, mid tcpip.NICID) tcpip.Error {
 	return nil
 }
 
+// SetNICAddress sets the hardware address which is identified by the nic ID.
+func (s *Stack) SetNICAddress(id tcpip.NICID, addr tcpip.LinkAddress) tcpip.Error {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	nic, ok := s.nics[id]
+	if !ok {
+		return &tcpip.ErrUnknownNICID{}
+	}
+	nic.NetworkLinkEndpoint.SetLinkAddress(addr)
+	return nil
+}
+
 // NICInfo captures the name and addresses assigned to a NIC.
 type NICInfo struct {
 	Name              string