From 8643933d6e58492cbe9d5c78124873ab40f65feb Mon Sep 17 00:00:00 2001
From: Eyal Soha <eyalsoha@google.com>
Date: Thu, 9 Jan 2020 13:06:24 -0800
Subject: Change BindToDeviceOption to store NICID

This makes it possible to call the sockopt from go even when the NIC has no
name.

PiperOrigin-RevId: 288955236
---
 pkg/sentry/socket/netstack/netstack.go | 29 ++++++++++++++++++++++++++---
 1 file changed, 26 insertions(+), 3 deletions(-)

(limited to 'pkg/sentry')

diff --git a/pkg/sentry/socket/netstack/netstack.go b/pkg/sentry/socket/netstack/netstack.go
index 9e0d69046..764f11a6b 100644
--- a/pkg/sentry/socket/netstack/netstack.go
+++ b/pkg/sentry/socket/netstack/netstack.go
@@ -985,13 +985,23 @@ func getSockOptSocket(t *kernel.Task, s socket.Socket, ep commonEndpoint, family
 		if err := ep.GetSockOpt(&v); err != nil {
 			return nil, syserr.TranslateNetstackError(err)
 		}
-		if len(v) == 0 {
+		if v == 0 {
 			return []byte{}, nil
 		}
 		if outLen < linux.IFNAMSIZ {
 			return nil, syserr.ErrInvalidArgument
 		}
-		return append([]byte(v), 0), nil
+		s := t.NetworkContext()
+		if s == nil {
+			return nil, syserr.ErrNoDevice
+		}
+		nic, ok := s.Interfaces()[int32(v)]
+		if !ok {
+			// The NICID no longer indicates a valid interface, probably because that
+			// interface was removed.
+			return nil, syserr.ErrUnknownDevice
+		}
+		return append([]byte(nic.Name), 0), nil
 
 	case linux.SO_BROADCAST:
 		if outLen < sizeOfInt32 {
@@ -1438,7 +1448,20 @@ func setSockOptSocket(t *kernel.Task, s socket.Socket, ep commonEndpoint, name i
 		if n == -1 {
 			n = len(optVal)
 		}
-		return syserr.TranslateNetstackError(ep.SetSockOpt(tcpip.BindToDeviceOption(optVal[:n])))
+		name := string(optVal[:n])
+		if name == "" {
+			return syserr.TranslateNetstackError(ep.SetSockOpt(tcpip.BindToDeviceOption(0)))
+		}
+		s := t.NetworkContext()
+		if s == nil {
+			return syserr.ErrNoDevice
+		}
+		for nicID, nic := range s.Interfaces() {
+			if nic.Name == name {
+				return syserr.TranslateNetstackError(ep.SetSockOpt(tcpip.BindToDeviceOption(nicID)))
+			}
+		}
+		return syserr.ErrUnknownDevice
 
 	case linux.SO_BROADCAST:
 		if len(optVal) < sizeOfInt32 {
-- 
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