Merge branch 'master' into ip-forwarding

- Merges aleksej-paschenko's with HEAD
- Adds vfs2 support for ip_forward

9 files changed, 710 insertions, 161 deletions

diff --git a/pkg/sentry/socket/unix/BUILD b/pkg/sentry/socket/unix/BUILD
index 5b6a154f6..cb953e4dc 100644
--- a/pkg/sentry/socket/unix/BUILD
+++ b/pkg/sentry/socket/unix/BUILD
@@ -1,35 +1,54 @@
-load("//tools/go_stateify:defs.bzl", "go_library")
+load("//tools:defs.bzl", "go_library")
+load("//tools/go_generics:defs.bzl", "go_template_instance")
 
 package(licenses = ["notice"])
 
+go_template_instance(
+    name = "socket_refs",
+    out = "socket_refs.go",
+    package = "unix",
+    prefix = "socketOpsCommon",
+    template = "//pkg/refs_vfs2:refs_template",
+    types = {
+        "T": "socketOpsCommon",
+    },
+)
+
 go_library(
     name = "unix",
     srcs = [
         "device.go",
         "io.go",
+        "socket_refs.go",
         "unix.go",
+        "unix_vfs2.go",
     ],
-    importpath = "gvisor.dev/gvisor/pkg/sentry/socket/unix",
     visibility = ["//pkg/sentry:internal"],
     deps = [
         "//pkg/abi/linux",
+        "//pkg/context",
+        "//pkg/fspath",
+        "//pkg/log",
         "//pkg/refs",
+        "//pkg/safemem",
         "//pkg/sentry/arch",
-        "//pkg/sentry/context",
         "//pkg/sentry/device",
         "//pkg/sentry/fs",
         "//pkg/sentry/fs/fsutil",
+        "//pkg/sentry/fs/lock",
+        "//pkg/sentry/fsimpl/sockfs",
         "//pkg/sentry/kernel",
         "//pkg/sentry/kernel/time",
-        "//pkg/sentry/safemem",
         "//pkg/sentry/socket",
         "//pkg/sentry/socket/control",
         "//pkg/sentry/socket/netstack",
         "//pkg/sentry/socket/unix/transport",
-        "//pkg/sentry/usermem",
+        "//pkg/sentry/vfs",
         "//pkg/syserr",
         "//pkg/syserror",
         "//pkg/tcpip",
+        "//pkg/usermem",
         "//pkg/waiter",
+        "//tools/go_marshal/marshal",
     ],
 )
diff --git a/pkg/sentry/socket/unix/io.go b/pkg/sentry/socket/unix/io.go
index 2ec1a662d..129949990 100644
--- a/pkg/sentry/socket/unix/io.go
+++ b/pkg/sentry/socket/unix/io.go
@@ -15,8 +15,8 @@
 package unix
 
 import (
-	"gvisor.dev/gvisor/pkg/sentry/context"
-	"gvisor.dev/gvisor/pkg/sentry/safemem"
+	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/safemem"
 	"gvisor.dev/gvisor/pkg/sentry/socket/unix/transport"
 	"gvisor.dev/gvisor/pkg/tcpip"
 )
@@ -83,6 +83,19 @@ type EndpointReader struct {
 	ControlTrunc bool
 }
 
+// Truncate calls RecvMsg on the endpoint without writing to a destination.
+func (r *EndpointReader) Truncate() error {
+	// Ignore bytes read since it will always be zero.
+	_, ms, c, ct, err := r.Endpoint.RecvMsg(r.Ctx, [][]byte{}, r.Creds, r.NumRights, r.Peek, r.From)
+	r.Control = c
+	r.ControlTrunc = ct
+	r.MsgSize = ms
+	if err != nil {
+		return err.ToError()
+	}
+	return nil
+}
+
 // ReadToBlocks implements safemem.Reader.ReadToBlocks.
 func (r *EndpointReader) ReadToBlocks(dsts safemem.BlockSeq) (uint64, error) {
 	return safemem.FromVecReaderFunc{func(bufs [][]byte) (int64, error) {
diff --git a/pkg/sentry/socket/unix/transport/BUILD b/pkg/sentry/socket/unix/transport/BUILD
index 788ad70d2..c708b6030 100644
--- a/pkg/sentry/socket/unix/transport/BUILD
+++ b/pkg/sentry/socket/unix/transport/BUILD
@@ -1,4 +1,4 @@
-load("//tools/go_stateify:defs.bzl", "go_library")
+load("//tools:defs.bzl", "go_library")
 load("//tools/go_generics:defs.bzl", "go_template_instance")
 
 package(licenses = ["notice"])
@@ -25,13 +25,14 @@ go_library(
         "transport_message_list.go",
         "unix.go",
     ],
-    importpath = "gvisor.dev/gvisor/pkg/sentry/socket/unix/transport",
     visibility = ["//:sandbox"],
     deps = [
         "//pkg/abi/linux",
+        "//pkg/context",
         "//pkg/ilist",
+        "//pkg/log",
         "//pkg/refs",
-        "//pkg/sentry/context",
+        "//pkg/sync",
         "//pkg/syserr",
         "//pkg/tcpip",
         "//pkg/tcpip/buffer",
diff --git a/pkg/sentry/socket/unix/transport/connectioned.go b/pkg/sentry/socket/unix/transport/connectioned.go
index dea11e253..c67b602f0 100644
--- a/pkg/sentry/socket/unix/transport/connectioned.go
+++ b/pkg/sentry/socket/unix/transport/connectioned.go
@@ -15,10 +15,9 @@
 package transport
 
 import (
-	"sync"
-
 	"gvisor.dev/gvisor/pkg/abi/linux"
-	"gvisor.dev/gvisor/pkg/sentry/context"
+	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserr"
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/waiter"
@@ -212,7 +211,7 @@ func (e *connectionedEndpoint) Listening() bool {
 // The socket will be a fresh state after a call to close and may be reused.
 // That is, close may be used to "unbind" or "disconnect" the socket in error
 // paths.
-func (e *connectionedEndpoint) Close() {
+func (e *connectionedEndpoint) Close(ctx context.Context) {
 	e.Lock()
 	var c ConnectedEndpoint
 	var r Receiver
@@ -234,7 +233,7 @@ func (e *connectionedEndpoint) Close() {
 	case e.Listening():
 		close(e.acceptedChan)
 		for n := range e.acceptedChan {
-			n.Close()
+			n.Close(ctx)
 		}
 		e.acceptedChan = nil
 		e.path = ""
@@ -242,18 +241,18 @@ func (e *connectionedEndpoint) Close() {
 	e.Unlock()
 	if c != nil {
 		c.CloseNotify()
-		c.Release()
+		c.Release(ctx)
 	}
 	if r != nil {
 		r.CloseNotify()
-		r.Release()
+		r.Release(ctx)
 	}
 }
 
 // BidirectionalConnect implements BoundEndpoint.BidirectionalConnect.
 func (e *connectionedEndpoint) BidirectionalConnect(ctx context.Context, ce ConnectingEndpoint, returnConnect func(Receiver, ConnectedEndpoint)) *syserr.Error {
 	if ce.Type() != e.stype {
-		return syserr.ErrConnectionRefused
+		return syserr.ErrWrongProtocolForSocket
 	}
 
 	// Check if ce is e to avoid a deadlock.
@@ -341,7 +340,7 @@ func (e *connectionedEndpoint) BidirectionalConnect(ctx context.Context, ce Conn
 		return nil
 	default:
 		// Busy; return ECONNREFUSED per spec.
-		ne.Close()
+		ne.Close(ctx)
 		e.Unlock()
 		ce.Unlock()
 		return syserr.ErrConnectionRefused
@@ -477,6 +476,9 @@ func (e *connectionedEndpoint) Readiness(mask waiter.EventMask) waiter.EventMask
 
 // State implements socket.Socket.State.
 func (e *connectionedEndpoint) State() uint32 {
+	e.Lock()
+	defer e.Unlock()
+
 	if e.Connected() {
 		return linux.SS_CONNECTED
 	}
diff --git a/pkg/sentry/socket/unix/transport/connectionless.go b/pkg/sentry/socket/unix/transport/connectionless.go
index 0322dec0b..70ee8f9b8 100644
--- a/pkg/sentry/socket/unix/transport/connectionless.go
+++ b/pkg/sentry/socket/unix/transport/connectionless.go
@@ -16,7 +16,7 @@ package transport
 
 import (
 	"gvisor.dev/gvisor/pkg/abi/linux"
-	"gvisor.dev/gvisor/pkg/sentry/context"
+	"gvisor.dev/gvisor/pkg/context"
 	"gvisor.dev/gvisor/pkg/syserr"
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/waiter"
@@ -54,10 +54,10 @@ func (e *connectionlessEndpoint) isBound() bool {
 
 // Close puts the endpoint in a closed state and frees all resources associated
 // with it.
-func (e *connectionlessEndpoint) Close() {
+func (e *connectionlessEndpoint) Close(ctx context.Context) {
 	e.Lock()
 	if e.connected != nil {
-		e.connected.Release()
+		e.connected.Release(ctx)
 		e.connected = nil
 	}
 
@@ -71,7 +71,7 @@ func (e *connectionlessEndpoint) Close() {
 	e.Unlock()
 
 	r.CloseNotify()
-	r.Release()
+	r.Release(ctx)
 }
 
 // BidirectionalConnect implements BoundEndpoint.BidirectionalConnect.
@@ -108,10 +108,10 @@ func (e *connectionlessEndpoint) SendMsg(ctx context.Context, data [][]byte, c C
 	if err != nil {
 		return 0, syserr.ErrInvalidEndpointState
 	}
-	defer connected.Release()
+	defer connected.Release(ctx)
 
 	e.Lock()
-	n, notify, err := connected.Send(data, c, tcpip.FullAddress{Addr: tcpip.Address(e.path)})
+	n, notify, err := connected.Send(ctx, data, c, tcpip.FullAddress{Addr: tcpip.Address(e.path)})
 	e.Unlock()
 
 	if notify {
@@ -135,7 +135,7 @@ func (e *connectionlessEndpoint) Connect(ctx context.Context, server BoundEndpoi
 
 	e.Lock()
 	if e.connected != nil {
-		e.connected.Release()
+		e.connected.Release(ctx)
 	}
 	e.connected = connected
 	e.Unlock()
diff --git a/pkg/sentry/socket/unix/transport/queue.go b/pkg/sentry/socket/unix/transport/queue.go
index e27b1c714..ef6043e19 100644
--- a/pkg/sentry/socket/unix/transport/queue.go
+++ b/pkg/sentry/socket/unix/transport/queue.go
@@ -15,10 +15,12 @@
 package transport
 
 import (
-	"sync"
-
+	"gvisor.dev/gvisor/pkg/context"
 	"gvisor.dev/gvisor/pkg/refs"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserr"
+	"gvisor.dev/gvisor/pkg/tcpip"
+	"gvisor.dev/gvisor/pkg/tcpip/buffer"
 	"gvisor.dev/gvisor/pkg/waiter"
 )
 
@@ -56,10 +58,10 @@ func (q *queue) Close() {
 // Both the read and write queues must be notified after resetting:
 // q.ReaderQueue.Notify(waiter.EventIn)
 // q.WriterQueue.Notify(waiter.EventOut)
-func (q *queue) Reset() {
+func (q *queue) Reset(ctx context.Context) {
 	q.mu.Lock()
 	for cur := q.dataList.Front(); cur != nil; cur = cur.Next() {
-		cur.Release()
+		cur.Release(ctx)
 	}
 	q.dataList.Reset()
 	q.used = 0
@@ -67,8 +69,8 @@ func (q *queue) Reset() {
 }
 
 // DecRef implements RefCounter.DecRef with destructor q.Reset.
-func (q *queue) DecRef() {
-	q.DecRefWithDestructor(q.Reset)
+func (q *queue) DecRef(ctx context.Context) {
+	q.DecRefWithDestructor(ctx, q.Reset)
 	// We don't need to notify after resetting because no one cares about
 	// this queue after all references have been dropped.
 }
@@ -101,12 +103,16 @@ func (q *queue) IsWritable() bool {
 
 // Enqueue adds an entry to the data queue if room is available.
 //
+// If discardEmpty is true and there are zero bytes of data, the packet is
+// dropped.
+//
 // If truncate is true, Enqueue may truncate the message before enqueuing it.
-// Otherwise, the entire message must fit. If n < e.Length(), err indicates why.
+// Otherwise, the entire message must fit. If l is less than the size of data,
+// err indicates why.
 //
 // If notify is true, ReaderQueue.Notify must be called:
 // q.ReaderQueue.Notify(waiter.EventIn)
-func (q *queue) Enqueue(e *message, truncate bool) (l int64, notify bool, err *syserr.Error) {
+func (q *queue) Enqueue(ctx context.Context, data [][]byte, c ControlMessages, from tcpip.FullAddress, discardEmpty bool, truncate bool) (l int64, notify bool, err *syserr.Error) {
 	q.mu.Lock()
 
 	if q.closed {
@@ -114,9 +120,16 @@ func (q *queue) Enqueue(e *message, truncate bool) (l int64, notify bool, err *s
 		return 0, false, syserr.ErrClosedForSend
 	}
 
-	free := q.limit - q.used
+	for _, d := range data {
+		l += int64(len(d))
+	}
+	if discardEmpty && l == 0 {
+		q.mu.Unlock()
+		c.Release(ctx)
+		return 0, false, nil
+	}
 
-	l = e.Length()
+	free := q.limit - q.used
 
 	if l > free && truncate {
 		if free == 0 {
@@ -125,8 +138,7 @@ func (q *queue) Enqueue(e *message, truncate bool) (l int64, notify bool, err *s
 			return 0, false, syserr.ErrWouldBlock
 		}
 
-		e.Truncate(free)
-		l = e.Length()
+		l = free
 		err = syserr.ErrWouldBlock
 	}
 
@@ -137,14 +149,26 @@ func (q *queue) Enqueue(e *message, truncate bool) (l int64, notify bool, err *s
 	}
 
 	if l > free {
-		// Message can't fit right now.
+		// Message can't fit right now, and could not be truncated.
 		q.mu.Unlock()
 		return 0, false, syserr.ErrWouldBlock
 	}
 
+	// Aggregate l bytes of data. This will truncate the data if l is less than
+	// the total bytes held in data.
+	v := make([]byte, l)
+	for i, b := 0, v; i < len(data) && len(b) > 0; i++ {
+		n := copy(b, data[i])
+		b = b[n:]
+	}
+
 	notify = q.dataList.Front() == nil
 	q.used += l
-	q.dataList.PushBack(e)
+	q.dataList.PushBack(&message{
+		Data:    buffer.View(v),
+		Control: c,
+		Address: from,
+	})
 
 	q.mu.Unlock()
 
diff --git a/pkg/sentry/socket/unix/transport/unix.go b/pkg/sentry/socket/unix/transport/unix.go
index 529a7a7a9..475d7177e 100644
--- a/pkg/sentry/socket/unix/transport/unix.go
+++ b/pkg/sentry/socket/unix/transport/unix.go
@@ -16,11 +16,12 @@
 package transport
 
 import (
-	"sync"
 	"sync/atomic"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
-	"gvisor.dev/gvisor/pkg/sentry/context"
+	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/log"
+	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserr"
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/buffer"
@@ -36,7 +37,7 @@ type RightsControlMessage interface {
 	Clone() RightsControlMessage
 
 	// Release releases any resources owned by the RightsControlMessage.
-	Release()
+	Release(ctx context.Context)
 }
 
 // A CredentialsControlMessage is a control message containing Unix credentials.
@@ -73,9 +74,9 @@ func (c *ControlMessages) Clone() ControlMessages {
 }
 
 // Release releases both the credentials and the rights.
-func (c *ControlMessages) Release() {
+func (c *ControlMessages) Release(ctx context.Context) {
 	if c.Rights != nil {
-		c.Rights.Release()
+		c.Rights.Release(ctx)
 	}
 	*c = ControlMessages{}
 }
@@ -89,7 +90,7 @@ type Endpoint interface {
 
 	// Close puts the endpoint in a closed state and frees all resources
 	// associated with it.
-	Close()
+	Close(ctx context.Context)
 
 	// RecvMsg reads data and a control message from the endpoint. This method
 	// does not block if there is no data pending.
@@ -175,17 +176,25 @@ type Endpoint interface {
 	// types.
 	SetSockOpt(opt interface{}) *tcpip.Error
 
+	// SetSockOptBool sets a socket option for simple cases when a value has
+	// the int type.
+	SetSockOptBool(opt tcpip.SockOptBool, v bool) *tcpip.Error
+
 	// SetSockOptInt sets a socket option for simple cases when a value has
 	// the int type.
-	SetSockOptInt(opt tcpip.SockOpt, v int) *tcpip.Error
+	SetSockOptInt(opt tcpip.SockOptInt, v int) *tcpip.Error
 
 	// GetSockOpt gets a socket option. opt should be a pointer to one of the
 	// tcpip.*Option types.
 	GetSockOpt(opt interface{}) *tcpip.Error
 
+	// GetSockOptBool gets a socket option for simple cases when a return
+	// value has the int type.
+	GetSockOptBool(opt tcpip.SockOptBool) (bool, *tcpip.Error)
+
 	// GetSockOptInt gets a socket option for simple cases when a return
 	// value has the int type.
-	GetSockOptInt(opt tcpip.SockOpt) (int, *tcpip.Error)
+	GetSockOptInt(opt tcpip.SockOptInt) (int, *tcpip.Error)
 
 	// State returns the current state of the socket, as represented by Linux in
 	// procfs.
@@ -243,7 +252,7 @@ type BoundEndpoint interface {
 	// Release releases any resources held by the BoundEndpoint. It must be
 	// called before dropping all references to a BoundEndpoint returned by a
 	// function.
-	Release()
+	Release(ctx context.Context)
 }
 
 // message represents a message passed over a Unix domain socket.
@@ -272,8 +281,8 @@ func (m *message) Length() int64 {
 }
 
 // Release releases any resources held by the message.
-func (m *message) Release() {
-	m.Control.Release()
+func (m *message) Release(ctx context.Context) {
+	m.Control.Release(ctx)
 }
 
 // Peek returns a copy of the message.
@@ -295,7 +304,7 @@ type Receiver interface {
 	// See Endpoint.RecvMsg for documentation on shared arguments.
 	//
 	// notify indicates if RecvNotify should be called.
-	Recv(data [][]byte, creds bool, numRights int, peek bool) (recvLen, msgLen int64, cm ControlMessages, CMTruncated bool, source tcpip.FullAddress, notify bool, err *syserr.Error)
+	Recv(ctx context.Context, data [][]byte, creds bool, numRights int, peek bool) (recvLen, msgLen int64, cm ControlMessages, CMTruncated bool, source tcpip.FullAddress, notify bool, err *syserr.Error)
 
 	// RecvNotify notifies the Receiver of a successful Recv. This must not be
 	// called while holding any endpoint locks.
@@ -324,7 +333,7 @@ type Receiver interface {
 
 	// Release releases any resources owned by the Receiver. It should be
 	// called before droping all references to a Receiver.
-	Release()
+	Release(ctx context.Context)
 }
 
 // queueReceiver implements Receiver for datagram sockets.
@@ -335,7 +344,7 @@ type queueReceiver struct {
 }
 
 // Recv implements Receiver.Recv.
-func (q *queueReceiver) Recv(data [][]byte, creds bool, numRights int, peek bool) (int64, int64, ControlMessages, bool, tcpip.FullAddress, bool, *syserr.Error) {
+func (q *queueReceiver) Recv(ctx context.Context, data [][]byte, creds bool, numRights int, peek bool) (int64, int64, ControlMessages, bool, tcpip.FullAddress, bool, *syserr.Error) {
 	var m *message
 	var notify bool
 	var err *syserr.Error
@@ -389,8 +398,8 @@ func (q *queueReceiver) RecvMaxQueueSize() int64 {
 }
 
 // Release implements Receiver.Release.
-func (q *queueReceiver) Release() {
-	q.readQueue.DecRef()
+func (q *queueReceiver) Release(ctx context.Context) {
+	q.readQueue.DecRef(ctx)
 }
 
 // streamQueueReceiver implements Receiver for stream sockets.
@@ -447,7 +456,7 @@ func (q *streamQueueReceiver) RecvMaxQueueSize() int64 {
 }
 
 // Recv implements Receiver.Recv.
-func (q *streamQueueReceiver) Recv(data [][]byte, wantCreds bool, numRights int, peek bool) (int64, int64, ControlMessages, bool, tcpip.FullAddress, bool, *syserr.Error) {
+func (q *streamQueueReceiver) Recv(ctx context.Context, data [][]byte, wantCreds bool, numRights int, peek bool) (int64, int64, ControlMessages, bool, tcpip.FullAddress, bool, *syserr.Error) {
 	q.mu.Lock()
 	defer q.mu.Unlock()
 
@@ -493,7 +502,7 @@ func (q *streamQueueReceiver) Recv(data [][]byte, wantCreds bool, numRights int,
 
 	var cmTruncated bool
 	if c.Rights != nil && numRights == 0 {
-		c.Rights.Release()
+		c.Rights.Release(ctx)
 		c.Rights = nil
 		cmTruncated = true
 	}
@@ -548,7 +557,7 @@ func (q *streamQueueReceiver) Recv(data [][]byte, wantCreds bool, numRights int,
 			// Consume rights.
 			if numRights == 0 {
 				cmTruncated = true
-				q.control.Rights.Release()
+				q.control.Rights.Release(ctx)
 			} else {
 				c.Rights = q.control.Rights
 				haveRights = true
@@ -573,7 +582,7 @@ type ConnectedEndpoint interface {
 	//
 	// syserr.ErrWouldBlock can be returned along with a partial write if
 	// the caller should block to send the rest of the data.
-	Send(data [][]byte, controlMessages ControlMessages, from tcpip.FullAddress) (n int64, notify bool, err *syserr.Error)
+	Send(ctx context.Context, data [][]byte, c ControlMessages, from tcpip.FullAddress) (n int64, notify bool, err *syserr.Error)
 
 	// SendNotify notifies the ConnectedEndpoint of a successful Send. This
 	// must not be called while holding any endpoint locks.
@@ -607,7 +616,7 @@ type ConnectedEndpoint interface {
 
 	// Release releases any resources owned by the ConnectedEndpoint. It should
 	// be called before droping all references to a ConnectedEndpoint.
-	Release()
+	Release(ctx context.Context)
 
 	// CloseUnread sets the fact that this end is closed with unread data to
 	// the peer socket.
@@ -645,35 +654,22 @@ func (e *connectedEndpoint) GetLocalAddress() (tcpip.FullAddress, *tcpip.Error)
 }
 
 // Send implements ConnectedEndpoint.Send.
-func (e *connectedEndpoint) Send(data [][]byte, controlMessages ControlMessages, from tcpip.FullAddress) (int64, bool, *syserr.Error) {
-	var l int64
-	for _, d := range data {
-		l += int64(len(d))
-	}
-
+func (e *connectedEndpoint) Send(ctx context.Context, data [][]byte, c ControlMessages, from tcpip.FullAddress) (int64, bool, *syserr.Error) {
+	discardEmpty := false
 	truncate := false
 	if e.endpoint.Type() == linux.SOCK_STREAM {
-		// Since stream sockets don't preserve message boundaries, we
-		// can write only as much of the message as fits in the queue.
-		truncate = true
-
 		// Discard empty stream packets. Since stream sockets don't
 		// preserve message boundaries, sending zero bytes is a no-op.
 		// In Linux, the receiver actually uses a zero-length receive
 		// as an indication that the stream was closed.
-		if l == 0 {
-			controlMessages.Release()
-			return 0, false, nil
-		}
-	}
+		discardEmpty = true
 
-	v := make([]byte, 0, l)
-	for _, d := range data {
-		v = append(v, d...)
+		// Since stream sockets don't preserve message boundaries, we
+		// can write only as much of the message as fits in the queue.
+		truncate = true
 	}
 
-	l, notify, err := e.writeQueue.Enqueue(&message{Data: buffer.View(v), Control: controlMessages, Address: from}, truncate)
-	return int64(l), notify, err
+	return e.writeQueue.Enqueue(ctx, data, c, from, discardEmpty, truncate)
 }
 
 // SendNotify implements ConnectedEndpoint.SendNotify.
@@ -711,8 +707,8 @@ func (e *connectedEndpoint) SendMaxQueueSize() int64 {
 }
 
 // Release implements ConnectedEndpoint.Release.
-func (e *connectedEndpoint) Release() {
-	e.writeQueue.DecRef()
+func (e *connectedEndpoint) Release(ctx context.Context) {
+	e.writeQueue.DecRef(ctx)
 }
 
 // CloseUnread implements ConnectedEndpoint.CloseUnread.
@@ -802,7 +798,7 @@ func (e *baseEndpoint) RecvMsg(ctx context.Context, data [][]byte, creds bool, n
 		return 0, 0, ControlMessages{}, false, syserr.ErrNotConnected
 	}
 
-	recvLen, msgLen, cms, cmt, a, notify, err := e.receiver.Recv(data, creds, numRights, peek)
+	recvLen, msgLen, cms, cmt, a, notify, err := e.receiver.Recv(ctx, data, creds, numRights, peek)
 	e.Unlock()
 	if err != nil {
 		return 0, 0, ControlMessages{}, false, err
@@ -831,7 +827,7 @@ func (e *baseEndpoint) SendMsg(ctx context.Context, data [][]byte, c ControlMess
 		return 0, syserr.ErrAlreadyConnected
 	}
 
-	n, notify, err := e.connected.Send(data, c, tcpip.FullAddress{Addr: tcpip.Address(e.path)})
+	n, notify, err := e.connected.Send(ctx, data, c, tcpip.FullAddress{Addr: tcpip.Address(e.path)})
 	e.Unlock()
 
 	if notify {
@@ -843,19 +839,46 @@ func (e *baseEndpoint) SendMsg(ctx context.Context, data [][]byte, c ControlMess
 
 // SetSockOpt sets a socket option. Currently not supported.
 func (e *baseEndpoint) SetSockOpt(opt interface{}) *tcpip.Error {
-	switch v := opt.(type) {
+	return nil
+}
+
+func (e *baseEndpoint) SetSockOptBool(opt tcpip.SockOptBool, v bool) *tcpip.Error {
+	switch opt {
+	case tcpip.BroadcastOption:
 	case tcpip.PasscredOption:
-		e.setPasscred(v != 0)
-		return nil
+		e.setPasscred(v)
+	case tcpip.ReuseAddressOption:
+	default:
+		log.Warningf("Unsupported socket option: %d", opt)
 	}
 	return nil
 }
 
-func (e *baseEndpoint) SetSockOptInt(opt tcpip.SockOpt, v int) *tcpip.Error {
+func (e *baseEndpoint) SetSockOptInt(opt tcpip.SockOptInt, v int) *tcpip.Error {
+	switch opt {
+	case tcpip.SendBufferSizeOption:
+	case tcpip.ReceiveBufferSizeOption:
+	default:
+		log.Warningf("Unsupported socket option: %d", opt)
+	}
 	return nil
 }
 
-func (e *baseEndpoint) GetSockOptInt(opt tcpip.SockOpt) (int, *tcpip.Error) {
+func (e *baseEndpoint) GetSockOptBool(opt tcpip.SockOptBool) (bool, *tcpip.Error) {
+	switch opt {
+	case tcpip.KeepaliveEnabledOption:
+		return false, nil
+
+	case tcpip.PasscredOption:
+		return e.Passcred(), nil
+
+	default:
+		log.Warningf("Unsupported socket option: %d", opt)
+		return false, tcpip.ErrUnknownProtocolOption
+	}
+}
+
+func (e *baseEndpoint) GetSockOptInt(opt tcpip.SockOptInt) (int, *tcpip.Error) {
 	switch opt {
 	case tcpip.ReceiveQueueSizeOption:
 		v := 0
@@ -911,29 +934,19 @@ func (e *baseEndpoint) GetSockOptInt(opt tcpip.SockOpt) (int, *tcpip.Error) {
 		return int(v), nil
 
 	default:
+		log.Warningf("Unsupported socket option: %d", opt)
 		return -1, tcpip.ErrUnknownProtocolOption
 	}
 }
 
 // GetSockOpt implements tcpip.Endpoint.GetSockOpt.
 func (e *baseEndpoint) GetSockOpt(opt interface{}) *tcpip.Error {
-	switch o := opt.(type) {
+	switch opt.(type) {
 	case tcpip.ErrorOption:
 		return nil
 
-	case *tcpip.PasscredOption:
-		if e.Passcred() {
-			*o = tcpip.PasscredOption(1)
-		} else {
-			*o = tcpip.PasscredOption(0)
-		}
-		return nil
-
-	case *tcpip.KeepaliveEnabledOption:
-		*o = 0
-		return nil
-
 	default:
+		log.Warningf("Unsupported socket option: %T", opt)
 		return tcpip.ErrUnknownProtocolOption
 	}
 }
@@ -988,6 +1001,6 @@ func (e *baseEndpoint) GetRemoteAddress() (tcpip.FullAddress, *tcpip.Error) {
 }
 
 // Release implements BoundEndpoint.Release.
-func (*baseEndpoint) Release() {
+func (*baseEndpoint) Release(context.Context) {
 	// Binding a baseEndpoint doesn't take a reference.
 }
diff --git a/pkg/sentry/socket/unix/unix.go b/pkg/sentry/socket/unix/unix.go
index 1aaae8487..b7e8e4325 100644
--- a/pkg/sentry/socket/unix/unix.go
+++ b/pkg/sentry/socket/unix/unix.go
@@ -22,9 +22,9 @@ import (
 	"syscall"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
-	"gvisor.dev/gvisor/pkg/refs"
+	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/fspath"
 	"gvisor.dev/gvisor/pkg/sentry/arch"
-	"gvisor.dev/gvisor/pkg/sentry/context"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	"gvisor.dev/gvisor/pkg/sentry/fs/fsutil"
 	"gvisor.dev/gvisor/pkg/sentry/kernel"
@@ -33,11 +33,13 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/socket/control"
 	"gvisor.dev/gvisor/pkg/sentry/socket/netstack"
 	"gvisor.dev/gvisor/pkg/sentry/socket/unix/transport"
-	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/sentry/vfs"
 	"gvisor.dev/gvisor/pkg/syserr"
 	"gvisor.dev/gvisor/pkg/syserror"
 	"gvisor.dev/gvisor/pkg/tcpip"
+	"gvisor.dev/gvisor/pkg/usermem"
 	"gvisor.dev/gvisor/pkg/waiter"
+	"gvisor.dev/gvisor/tools/go_marshal/marshal"
 )
 
 // SocketOperations is a Unix socket. It is similar to a netstack socket,
@@ -52,17 +54,14 @@ type SocketOperations struct {
 	fsutil.FileNoSplice             `state:"nosave"`
 	fsutil.FileNoopFlush            `state:"nosave"`
 	fsutil.FileUseInodeUnstableAttr `state:"nosave"`
-	refs.AtomicRefCount
-	socket.SendReceiveTimeout
 
-	ep    transport.Endpoint
-	stype linux.SockType
+	socketOpsCommon
 }
 
 // New creates a new unix socket.
 func New(ctx context.Context, endpoint transport.Endpoint, stype linux.SockType) *fs.File {
 	dirent := socket.NewDirent(ctx, unixSocketDevice)
-	defer dirent.DecRef()
+	defer dirent.DecRef(ctx)
 	return NewWithDirent(ctx, dirent, endpoint, stype, fs.FileFlags{Read: true, Write: true, NonSeekable: true})
 }
 
@@ -75,29 +74,51 @@ func NewWithDirent(ctx context.Context, d *fs.Dirent, ep transport.Endpoint, sty
 	}
 
 	s := SocketOperations{
-		ep:    ep,
-		stype: stype,
+		socketOpsCommon: socketOpsCommon{
+			ep:    ep,
+			stype: stype,
+		},
 	}
-	s.EnableLeakCheck("unix.SocketOperations")
+	s.EnableLeakCheck()
 
 	return fs.NewFile(ctx, d, flags, &s)
 }
 
+// socketOpsCommon contains the socket operations common to VFS1 and VFS2.
+//
+// +stateify savable
+type socketOpsCommon struct {
+	socketOpsCommonRefs
+	socket.SendReceiveTimeout
+
+	ep    transport.Endpoint
+	stype linux.SockType
+
+	// abstractName and abstractNamespace indicate the name and namespace of the
+	// socket if it is bound to an abstract socket namespace. Once the socket is
+	// bound, they cannot be modified.
+	abstractName      string
+	abstractNamespace *kernel.AbstractSocketNamespace
+}
+
 // DecRef implements RefCounter.DecRef.
-func (s *SocketOperations) DecRef() {
-	s.DecRefWithDestructor(func() {
-		s.ep.Close()
+func (s *socketOpsCommon) DecRef(ctx context.Context) {
+	s.socketOpsCommonRefs.DecRef(func() {
+		s.ep.Close(ctx)
+		if s.abstractNamespace != nil {
+			s.abstractNamespace.Remove(s.abstractName, s)
+		}
 	})
 }
 
 // Release implemements fs.FileOperations.Release.
-func (s *SocketOperations) Release() {
+func (s *socketOpsCommon) Release(ctx context.Context) {
 	// Release only decrements a reference on s because s may be referenced in
 	// the abstract socket namespace.
-	s.DecRef()
+	s.DecRef(ctx)
 }
 
-func (s *SocketOperations) isPacket() bool {
+func (s *socketOpsCommon) isPacket() bool {
 	switch s.stype {
 	case linux.SOCK_DGRAM, linux.SOCK_SEQPACKET:
 		return true
@@ -110,16 +131,22 @@ func (s *SocketOperations) isPacket() bool {
 }
 
 // Endpoint extracts the transport.Endpoint.
-func (s *SocketOperations) Endpoint() transport.Endpoint {
+func (s *socketOpsCommon) Endpoint() transport.Endpoint {
 	return s.ep
 }
 
 // extractPath extracts and validates the address.
 func extractPath(sockaddr []byte) (string, *syserr.Error) {
-	addr, _, err := netstack.AddressAndFamily(linux.AF_UNIX, sockaddr, true /* strict */)
+	addr, family, err := netstack.AddressAndFamily(sockaddr)
 	if err != nil {
+		if err == syserr.ErrAddressFamilyNotSupported {
+			err = syserr.ErrInvalidArgument
+		}
 		return "", err
 	}
+	if family != linux.AF_UNIX {
+		return "", syserr.ErrInvalidArgument
+	}
 
 	// The address is trimmed by GetAddress.
 	p := string(addr.Addr)
@@ -137,7 +164,7 @@ func extractPath(sockaddr []byte) (string, *syserr.Error) {
 
 // GetPeerName implements the linux syscall getpeername(2) for sockets backed by
 // a transport.Endpoint.
-func (s *SocketOperations) GetPeerName(t *kernel.Task) (linux.SockAddr, uint32, *syserr.Error) {
+func (s *socketOpsCommon) GetPeerName(t *kernel.Task) (linux.SockAddr, uint32, *syserr.Error) {
 	addr, err := s.ep.GetRemoteAddress()
 	if err != nil {
 		return nil, 0, syserr.TranslateNetstackError(err)
@@ -149,7 +176,7 @@ func (s *SocketOperations) GetPeerName(t *kernel.Task) (linux.SockAddr, uint32,
 
 // GetSockName implements the linux syscall getsockname(2) for sockets backed by
 // a transport.Endpoint.
-func (s *SocketOperations) GetSockName(t *kernel.Task) (linux.SockAddr, uint32, *syserr.Error) {
+func (s *socketOpsCommon) GetSockName(t *kernel.Task) (linux.SockAddr, uint32, *syserr.Error) {
 	addr, err := s.ep.GetLocalAddress()
 	if err != nil {
 		return nil, 0, syserr.TranslateNetstackError(err)
@@ -166,13 +193,13 @@ func (s *SocketOperations) Ioctl(ctx context.Context, _ *fs.File, io usermem.IO,
 
 // GetSockOpt implements the linux syscall getsockopt(2) for sockets backed by
 // a transport.Endpoint.
-func (s *SocketOperations) GetSockOpt(t *kernel.Task, level, name int, outPtr usermem.Addr, outLen int) (interface{}, *syserr.Error) {
+func (s *SocketOperations) GetSockOpt(t *kernel.Task, level, name int, outPtr usermem.Addr, outLen int) (marshal.Marshallable, *syserr.Error) {
 	return netstack.GetSockOpt(t, s, s.ep, linux.AF_UNIX, s.ep.Type(), level, name, outLen)
 }
 
 // Listen implements the linux syscall listen(2) for sockets backed by
 // a transport.Endpoint.
-func (s *SocketOperations) Listen(t *kernel.Task, backlog int) *syserr.Error {
+func (s *socketOpsCommon) Listen(t *kernel.Task, backlog int) *syserr.Error {
 	return s.ep.Listen(backlog)
 }
 
@@ -215,7 +242,7 @@ func (s *SocketOperations) Accept(t *kernel.Task, peerRequested bool, flags int,
 	}
 
 	ns := New(t, ep, s.stype)
-	defer ns.DecRef()
+	defer ns.DecRef(t)
 
 	if flags&linux.SOCK_NONBLOCK != 0 {
 		flags := ns.Flags()
@@ -265,17 +292,21 @@ func (s *SocketOperations) Bind(t *kernel.Task, sockaddr []byte) *syserr.Error {
 			if t.IsNetworkNamespaced() {
 				return syserr.ErrInvalidEndpointState
 			}
-			if err := t.AbstractSockets().Bind(p[1:], bep, s); err != nil {
+			asn := t.AbstractSockets()
+			name := p[1:]
+			if err := asn.Bind(t, name, bep, s); err != nil {
 				// syserr.ErrPortInUse corresponds to EADDRINUSE.
 				return syserr.ErrPortInUse
 			}
+			s.abstractName = name
+			s.abstractNamespace = asn
 		} else {
 			// The parent and name.
 			var d *fs.Dirent
 			var name string
 
 			cwd := t.FSContext().WorkingDirectory()
-			defer cwd.DecRef()
+			defer cwd.DecRef(t)
 
 			// Is there no slash at all?
 			if !strings.Contains(p, "/") {
@@ -283,7 +314,7 @@ func (s *SocketOperations) Bind(t *kernel.Task, sockaddr []byte) *syserr.Error {
 				name = p
 			} else {
 				root := t.FSContext().RootDirectory()
-				defer root.DecRef()
+				defer root.DecRef(t)
 				// Find the last path component, we know that something follows
 				// that final slash, otherwise extractPath() would have failed.
 				lastSlash := strings.LastIndex(p, "/")
@@ -299,16 +330,21 @@ func (s *SocketOperations) Bind(t *kernel.Task, sockaddr []byte) *syserr.Error {
 					// No path available.
 					return syserr.ErrNoSuchFile
 				}
-				defer d.DecRef()
+				defer d.DecRef(t)
 				name = p[lastSlash+1:]
 			}
 
 			// Create the socket.
+			//
+			// Note that the file permissions here are not set correctly (see
+			// gvisor.dev/issue/2324). There is no convenient way to get permissions
+			// on the socket referred to by s, so we will leave this discrepancy
+			// unresolved until VFS2 replaces this code.
 			childDir, err := d.Bind(t, t.FSContext().RootDirectory(), name, bep, fs.FilePermissions{User: fs.PermMask{Read: true}})
 			if err != nil {
 				return syserr.ErrPortInUse
 			}
-			childDir.DecRef()
+			childDir.DecRef(t)
 		}
 
 		return nil
@@ -339,41 +375,76 @@ func extractEndpoint(t *kernel.Task, sockaddr []byte) (transport.BoundEndpoint,
 		return ep, nil
 	}
 
+	if kernel.VFS2Enabled {
+		p := fspath.Parse(path)
+		root := t.FSContext().RootDirectoryVFS2()
+		start := root
+		relPath := !p.Absolute
+		if relPath {
+			start = t.FSContext().WorkingDirectoryVFS2()
+		}
+		pop := vfs.PathOperation{
+			Root:               root,
+			Start:              start,
+			Path:               p,
+			FollowFinalSymlink: true,
+		}
+		ep, e := t.Kernel().VFS().BoundEndpointAt(t, t.Credentials(), &pop, &vfs.BoundEndpointOptions{path})
+		root.DecRef(t)
+		if relPath {
+			start.DecRef(t)
+		}
+		if e != nil {
+			return nil, syserr.FromError(e)
+		}
+		return ep, nil
+	}
+
 	// Find the node in the filesystem.
 	root := t.FSContext().RootDirectory()
 	cwd := t.FSContext().WorkingDirectory()
 	remainingTraversals := uint(fs.DefaultTraversalLimit)
 	d, e := t.MountNamespace().FindInode(t, root, cwd, path, &remainingTraversals)
-	cwd.DecRef()
-	root.DecRef()
+	cwd.DecRef(t)
+	root.DecRef(t)
 	if e != nil {
 		return nil, syserr.FromError(e)
 	}
 
 	// Extract the endpoint if one is there.
 	ep := d.Inode.BoundEndpoint(path)
-	d.DecRef()
+	d.DecRef(t)
 	if ep == nil {
 		// No socket!
 		return nil, syserr.ErrConnectionRefused
 	}
-
 	return ep, nil
 }
 
 // Connect implements the linux syscall connect(2) for unix sockets.
-func (s *SocketOperations) Connect(t *kernel.Task, sockaddr []byte, blocking bool) *syserr.Error {
+func (s *socketOpsCommon) Connect(t *kernel.Task, sockaddr []byte, blocking bool) *syserr.Error {
 	ep, err := extractEndpoint(t, sockaddr)
 	if err != nil {
 		return err
 	}
-	defer ep.Release()
+	defer ep.Release(t)
 
 	// Connect the server endpoint.
-	return s.ep.Connect(t, ep)
+	err = s.ep.Connect(t, ep)
+
+	if err == syserr.ErrWrongProtocolForSocket {
+		// Linux for abstract sockets returns ErrConnectionRefused
+		// instead of ErrWrongProtocolForSocket.
+		path, _ := extractPath(sockaddr)
+		if len(path) > 0 && path[0] == 0 {
+			err = syserr.ErrConnectionRefused
+		}
+	}
+
+	return err
 }
 
-// Writev implements fs.FileOperations.Write.
+// Write implements fs.FileOperations.Write.
 func (s *SocketOperations) Write(ctx context.Context, _ *fs.File, src usermem.IOSequence, _ int64) (int64, error) {
 	t := kernel.TaskFromContext(ctx)
 	ctrl := control.New(t, s.ep, nil)
@@ -393,7 +464,7 @@ func (s *SocketOperations) Write(ctx context.Context, _ *fs.File, src usermem.IO
 
 // SendMsg implements the linux syscall sendmsg(2) for unix sockets backed by
 // a transport.Endpoint.
-func (s *SocketOperations) SendMsg(t *kernel.Task, src usermem.IOSequence, to []byte, flags int, haveDeadline bool, deadline ktime.Time, controlMessages socket.ControlMessages) (int, *syserr.Error) {
+func (s *socketOpsCommon) SendMsg(t *kernel.Task, src usermem.IOSequence, to []byte, flags int, haveDeadline bool, deadline ktime.Time, controlMessages socket.ControlMessages) (int, *syserr.Error) {
 	w := EndpointWriter{
 		Ctx:      t,
 		Endpoint: s.ep,
@@ -401,15 +472,25 @@ func (s *SocketOperations) SendMsg(t *kernel.Task, src usermem.IOSequence, to []
 		To:       nil,
 	}
 	if len(to) > 0 {
-		ep, err := extractEndpoint(t, to)
-		if err != nil {
-			return 0, err
-		}
-		defer ep.Release()
-		w.To = ep
+		switch s.stype {
+		case linux.SOCK_SEQPACKET:
+			to = nil
+		case linux.SOCK_STREAM:
+			if s.State() == linux.SS_CONNECTED {
+				return 0, syserr.ErrAlreadyConnected
+			}
+			return 0, syserr.ErrNotSupported
+		default:
+			ep, err := extractEndpoint(t, to)
+			if err != nil {
+				return 0, err
+			}
+			defer ep.Release(t)
+			w.To = ep
 
-		if ep.Passcred() && w.Control.Credentials == nil {
-			w.Control.Credentials = control.MakeCreds(t)
+			if ep.Passcred() && w.Control.Credentials == nil {
+				w.Control.Credentials = control.MakeCreds(t)
+			}
 		}
 	}
 
@@ -447,27 +528,27 @@ func (s *SocketOperations) SendMsg(t *kernel.Task, src usermem.IOSequence, to []
 }
 
 // Passcred implements transport.Credentialer.Passcred.
-func (s *SocketOperations) Passcred() bool {
+func (s *socketOpsCommon) Passcred() bool {
 	return s.ep.Passcred()
 }
 
 // ConnectedPasscred implements transport.Credentialer.ConnectedPasscred.
-func (s *SocketOperations) ConnectedPasscred() bool {
+func (s *socketOpsCommon) ConnectedPasscred() bool {
 	return s.ep.ConnectedPasscred()
 }
 
 // Readiness implements waiter.Waitable.Readiness.
-func (s *SocketOperations) Readiness(mask waiter.EventMask) waiter.EventMask {
+func (s *socketOpsCommon) Readiness(mask waiter.EventMask) waiter.EventMask {
 	return s.ep.Readiness(mask)
 }
 
 // EventRegister implements waiter.Waitable.EventRegister.
-func (s *SocketOperations) EventRegister(e *waiter.Entry, mask waiter.EventMask) {
+func (s *socketOpsCommon) EventRegister(e *waiter.Entry, mask waiter.EventMask) {
 	s.ep.EventRegister(e, mask)
 }
 
 // EventUnregister implements waiter.Waitable.EventUnregister.
-func (s *SocketOperations) EventUnregister(e *waiter.Entry) {
+func (s *socketOpsCommon) EventUnregister(e *waiter.Entry) {
 	s.ep.EventUnregister(e)
 }
 
@@ -479,7 +560,7 @@ func (s *SocketOperations) SetSockOpt(t *kernel.Task, level int, name int, optVa
 
 // Shutdown implements the linux syscall shutdown(2) for sockets backed by
 // a transport.Endpoint.
-func (s *SocketOperations) Shutdown(t *kernel.Task, how int) *syserr.Error {
+func (s *socketOpsCommon) Shutdown(t *kernel.Task, how int) *syserr.Error {
 	f, err := netstack.ConvertShutdown(how)
 	if err != nil {
 		return err
@@ -505,7 +586,7 @@ func (s *SocketOperations) Read(ctx context.Context, _ *fs.File, dst usermem.IOS
 
 // RecvMsg implements the linux syscall recvmsg(2) for sockets backed by
 // a transport.Endpoint.
-func (s *SocketOperations) RecvMsg(t *kernel.Task, dst usermem.IOSequence, flags int, haveDeadline bool, deadline ktime.Time, senderRequested bool, controlDataLen uint64) (n int, msgFlags int, senderAddr linux.SockAddr, senderAddrLen uint32, controlMessages socket.ControlMessages, err *syserr.Error) {
+func (s *socketOpsCommon) RecvMsg(t *kernel.Task, dst usermem.IOSequence, flags int, haveDeadline bool, deadline ktime.Time, senderRequested bool, controlDataLen uint64) (n int, msgFlags int, senderAddr linux.SockAddr, senderAddrLen uint32, controlMessages socket.ControlMessages, err *syserr.Error) {
 	trunc := flags&linux.MSG_TRUNC != 0
 	peek := flags&linux.MSG_PEEK != 0
 	dontWait := flags&linux.MSG_DONTWAIT != 0
@@ -541,8 +622,27 @@ func (s *SocketOperations) RecvMsg(t *kernel.Task, dst usermem.IOSequence, flags
 	if senderRequested {
 		r.From = &tcpip.FullAddress{}
 	}
+
+	doRead := func() (int64, error) {
+		return dst.CopyOutFrom(t, &r)
+	}
+
+	// If MSG_TRUNC is set with a zero byte destination then we still need
+	// to read the message and discard it, or in the case where MSG_PEEK is
+	// set, leave it be. In both cases the full message length must be
+	// returned.
+	if trunc && dst.Addrs.NumBytes() == 0 {
+		doRead = func() (int64, error) {
+			err := r.Truncate()
+			// Always return zero for bytes read since the destination size is
+			// zero.
+			return 0, err
+		}
+
+	}
+
 	var total int64
-	if n, err := dst.CopyOutFrom(t, &r); err != syserror.ErrWouldBlock || dontWait {
+	if n, err := doRead(); err != syserror.ErrWouldBlock || dontWait {
 		var from linux.SockAddr
 		var fromLen uint32
 		if r.From != nil && len([]byte(r.From.Addr)) != 0 {
@@ -577,7 +677,7 @@ func (s *SocketOperations) RecvMsg(t *kernel.Task, dst usermem.IOSequence, flags
 	defer s.EventUnregister(&e)
 
 	for {
-		if n, err := dst.CopyOutFrom(t, &r); err != syserror.ErrWouldBlock {
+		if n, err := doRead(); err != syserror.ErrWouldBlock {
 			var from linux.SockAddr
 			var fromLen uint32
 			if r.From != nil {
@@ -623,12 +723,12 @@ func (s *SocketOperations) RecvMsg(t *kernel.Task, dst usermem.IOSequence, flags
 }
 
 // State implements socket.Socket.State.
-func (s *SocketOperations) State() uint32 {
+func (s *socketOpsCommon) State() uint32 {
 	return s.ep.State()
 }
 
 // Type implements socket.Socket.Type.
-func (s *SocketOperations) Type() (family int, skType linux.SockType, protocol int) {
+func (s *socketOpsCommon) Type() (family int, skType linux.SockType, protocol int) {
 	// Unix domain sockets always have a protocol of 0.
 	return linux.AF_UNIX, s.stype, 0
 }
@@ -681,4 +781,5 @@ func (*provider) Pair(t *kernel.Task, stype linux.SockType, protocol int) (*fs.F
 
 func init() {
 	socket.RegisterProvider(linux.AF_UNIX, &provider{})
+	socket.RegisterProviderVFS2(linux.AF_UNIX, &providerVFS2{})
 }
diff --git a/pkg/sentry/socket/unix/unix_vfs2.go b/pkg/sentry/socket/unix/unix_vfs2.go
new file mode 100644
index 000000000..d066ef8ab
--- /dev/null
+++ b/pkg/sentry/socket/unix/unix_vfs2.go
@@ -0,0 +1,376 @@
+// Copyright 2018 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package unix
+
+import (
+	"gvisor.dev/gvisor/pkg/abi/linux"
+	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/fspath"
+	"gvisor.dev/gvisor/pkg/sentry/arch"
+	fslock "gvisor.dev/gvisor/pkg/sentry/fs/lock"
+	"gvisor.dev/gvisor/pkg/sentry/fsimpl/sockfs"
+	"gvisor.dev/gvisor/pkg/sentry/kernel"
+	"gvisor.dev/gvisor/pkg/sentry/socket"
+	"gvisor.dev/gvisor/pkg/sentry/socket/control"
+	"gvisor.dev/gvisor/pkg/sentry/socket/netstack"
+	"gvisor.dev/gvisor/pkg/sentry/socket/unix/transport"
+	"gvisor.dev/gvisor/pkg/sentry/vfs"
+	"gvisor.dev/gvisor/pkg/syserr"
+	"gvisor.dev/gvisor/pkg/syserror"
+	"gvisor.dev/gvisor/pkg/tcpip"
+	"gvisor.dev/gvisor/pkg/usermem"
+	"gvisor.dev/gvisor/pkg/waiter"
+	"gvisor.dev/gvisor/tools/go_marshal/marshal"
+)
+
+// SocketVFS2 implements socket.SocketVFS2 (and by extension,
+// vfs.FileDescriptionImpl) for Unix sockets.
+type SocketVFS2 struct {
+	vfsfd vfs.FileDescription
+	vfs.FileDescriptionDefaultImpl
+	vfs.DentryMetadataFileDescriptionImpl
+	vfs.LockFD
+
+	socketOpsCommon
+}
+
+var _ = socket.SocketVFS2(&SocketVFS2{})
+
+// NewSockfsFile creates a new socket file in the global sockfs mount and
+// returns a corresponding file description.
+func NewSockfsFile(t *kernel.Task, ep transport.Endpoint, stype linux.SockType) (*vfs.FileDescription, *syserr.Error) {
+	mnt := t.Kernel().SocketMount()
+	d := sockfs.NewDentry(t.Credentials(), mnt)
+
+	fd, err := NewFileDescription(ep, stype, linux.O_RDWR, mnt, d, &vfs.FileLocks{})
+	if err != nil {
+		return nil, syserr.FromError(err)
+	}
+	return fd, nil
+}
+
+// NewFileDescription creates and returns a socket file description
+// corresponding to the given mount and dentry.
+func NewFileDescription(ep transport.Endpoint, stype linux.SockType, flags uint32, mnt *vfs.Mount, d *vfs.Dentry, locks *vfs.FileLocks) (*vfs.FileDescription, error) {
+	// You can create AF_UNIX, SOCK_RAW sockets. They're the same as
+	// SOCK_DGRAM and don't require CAP_NET_RAW.
+	if stype == linux.SOCK_RAW {
+		stype = linux.SOCK_DGRAM
+	}
+
+	sock := &SocketVFS2{
+		socketOpsCommon: socketOpsCommon{
+			ep:    ep,
+			stype: stype,
+		},
+	}
+	sock.LockFD.Init(locks)
+	vfsfd := &sock.vfsfd
+	if err := vfsfd.Init(sock, flags, mnt, d, &vfs.FileDescriptionOptions{
+		DenyPRead:         true,
+		DenyPWrite:        true,
+		UseDentryMetadata: true,
+	}); err != nil {
+		return nil, err
+	}
+	return vfsfd, nil
+}
+
+// GetSockOpt implements the linux syscall getsockopt(2) for sockets backed by
+// a transport.Endpoint.
+func (s *SocketVFS2) GetSockOpt(t *kernel.Task, level, name int, outPtr usermem.Addr, outLen int) (marshal.Marshallable, *syserr.Error) {
+	return netstack.GetSockOpt(t, s, s.ep, linux.AF_UNIX, s.ep.Type(), level, name, outLen)
+}
+
+// blockingAccept implements a blocking version of accept(2), that is, if no
+// connections are ready to be accept, it will block until one becomes ready.
+func (s *SocketVFS2) blockingAccept(t *kernel.Task) (transport.Endpoint, *syserr.Error) {
+	// Register for notifications.
+	e, ch := waiter.NewChannelEntry(nil)
+	s.socketOpsCommon.EventRegister(&e, waiter.EventIn)
+	defer s.socketOpsCommon.EventUnregister(&e)
+
+	// Try to accept the connection; if it fails, then wait until we get a
+	// notification.
+	for {
+		if ep, err := s.ep.Accept(); err != syserr.ErrWouldBlock {
+			return ep, err
+		}
+
+		if err := t.Block(ch); err != nil {
+			return nil, syserr.FromError(err)
+		}
+	}
+}
+
+// Accept implements the linux syscall accept(2) for sockets backed by
+// a transport.Endpoint.
+func (s *SocketVFS2) Accept(t *kernel.Task, peerRequested bool, flags int, blocking bool) (int32, linux.SockAddr, uint32, *syserr.Error) {
+	// Issue the accept request to get the new endpoint.
+	ep, err := s.ep.Accept()
+	if err != nil {
+		if err != syserr.ErrWouldBlock || !blocking {
+			return 0, nil, 0, err
+		}
+
+		var err *syserr.Error
+		ep, err = s.blockingAccept(t)
+		if err != nil {
+			return 0, nil, 0, err
+		}
+	}
+
+	ns, err := NewSockfsFile(t, ep, s.stype)
+	if err != nil {
+		return 0, nil, 0, err
+	}
+	defer ns.DecRef(t)
+
+	if flags&linux.SOCK_NONBLOCK != 0 {
+		ns.SetStatusFlags(t, t.Credentials(), linux.SOCK_NONBLOCK)
+	}
+
+	var addr linux.SockAddr
+	var addrLen uint32
+	if peerRequested {
+		// Get address of the peer.
+		var err *syserr.Error
+		addr, addrLen, err = ns.Impl().(*SocketVFS2).GetPeerName(t)
+		if err != nil {
+			return 0, nil, 0, err
+		}
+	}
+
+	fd, e := t.NewFDFromVFS2(0, ns, kernel.FDFlags{
+		CloseOnExec: flags&linux.SOCK_CLOEXEC != 0,
+	})
+	if e != nil {
+		return 0, nil, 0, syserr.FromError(e)
+	}
+
+	t.Kernel().RecordSocketVFS2(ns)
+	return fd, addr, addrLen, nil
+}
+
+// Bind implements the linux syscall bind(2) for unix sockets.
+func (s *SocketVFS2) Bind(t *kernel.Task, sockaddr []byte) *syserr.Error {
+	p, e := extractPath(sockaddr)
+	if e != nil {
+		return e
+	}
+
+	bep, ok := s.ep.(transport.BoundEndpoint)
+	if !ok {
+		// This socket can't be bound.
+		return syserr.ErrInvalidArgument
+	}
+
+	return s.ep.Bind(tcpip.FullAddress{Addr: tcpip.Address(p)}, func() *syserr.Error {
+		// Is it abstract?
+		if p[0] == 0 {
+			if t.IsNetworkNamespaced() {
+				return syserr.ErrInvalidEndpointState
+			}
+			asn := t.AbstractSockets()
+			name := p[1:]
+			if err := asn.Bind(t, name, bep, s); err != nil {
+				// syserr.ErrPortInUse corresponds to EADDRINUSE.
+				return syserr.ErrPortInUse
+			}
+			s.abstractName = name
+			s.abstractNamespace = asn
+		} else {
+			path := fspath.Parse(p)
+			root := t.FSContext().RootDirectoryVFS2()
+			defer root.DecRef(t)
+			start := root
+			relPath := !path.Absolute
+			if relPath {
+				start = t.FSContext().WorkingDirectoryVFS2()
+				defer start.DecRef(t)
+			}
+			pop := vfs.PathOperation{
+				Root:  root,
+				Start: start,
+				Path:  path,
+			}
+			stat, err := s.vfsfd.Stat(t, vfs.StatOptions{Mask: linux.STATX_MODE})
+			if err != nil {
+				return syserr.FromError(err)
+			}
+			err = t.Kernel().VFS().MknodAt(t, t.Credentials(), &pop, &vfs.MknodOptions{
+				// File permissions correspond to net/unix/af_unix.c:unix_bind.
+				Mode:     linux.FileMode(linux.S_IFSOCK | uint(stat.Mode)&^t.FSContext().Umask()),
+				Endpoint: bep,
+			})
+			if err == syserror.EEXIST {
+				return syserr.ErrAddressInUse
+			}
+			return syserr.FromError(err)
+		}
+
+		return nil
+	})
+}
+
+// Ioctl implements vfs.FileDescriptionImpl.
+func (s *SocketVFS2) Ioctl(ctx context.Context, uio usermem.IO, args arch.SyscallArguments) (uintptr, error) {
+	return netstack.Ioctl(ctx, s.ep, uio, args)
+}
+
+// PRead implements vfs.FileDescriptionImpl.
+func (s *SocketVFS2) PRead(ctx context.Context, dst usermem.IOSequence, offset int64, opts vfs.ReadOptions) (int64, error) {
+	return 0, syserror.ESPIPE
+}
+
+// Read implements vfs.FileDescriptionImpl.
+func (s *SocketVFS2) Read(ctx context.Context, dst usermem.IOSequence, opts vfs.ReadOptions) (int64, error) {
+	// All flags other than RWF_NOWAIT should be ignored.
+	// TODO(gvisor.dev/issue/2601): Support RWF_NOWAIT.
+	if opts.Flags != 0 {
+		return 0, syserror.EOPNOTSUPP
+	}
+
+	if dst.NumBytes() == 0 {
+		return 0, nil
+	}
+	return dst.CopyOutFrom(ctx, &EndpointReader{
+		Ctx:       ctx,
+		Endpoint:  s.ep,
+		NumRights: 0,
+		Peek:      false,
+		From:      nil,
+	})
+}
+
+// PWrite implements vfs.FileDescriptionImpl.
+func (s *SocketVFS2) PWrite(ctx context.Context, src usermem.IOSequence, offset int64, opts vfs.WriteOptions) (int64, error) {
+	return 0, syserror.ESPIPE
+}
+
+// Write implements vfs.FileDescriptionImpl.
+func (s *SocketVFS2) Write(ctx context.Context, src usermem.IOSequence, opts vfs.WriteOptions) (int64, error) {
+	// All flags other than RWF_NOWAIT should be ignored.
+	// TODO(gvisor.dev/issue/2601): Support RWF_NOWAIT.
+	if opts.Flags != 0 {
+		return 0, syserror.EOPNOTSUPP
+	}
+
+	t := kernel.TaskFromContext(ctx)
+	ctrl := control.New(t, s.ep, nil)
+
+	if src.NumBytes() == 0 {
+		nInt, err := s.ep.SendMsg(ctx, [][]byte{}, ctrl, nil)
+		return int64(nInt), err.ToError()
+	}
+
+	return src.CopyInTo(ctx, &EndpointWriter{
+		Ctx:      ctx,
+		Endpoint: s.ep,
+		Control:  ctrl,
+		To:       nil,
+	})
+}
+
+// Readiness implements waiter.Waitable.Readiness.
+func (s *SocketVFS2) Readiness(mask waiter.EventMask) waiter.EventMask {
+	return s.socketOpsCommon.Readiness(mask)
+}
+
+// EventRegister implements waiter.Waitable.EventRegister.
+func (s *SocketVFS2) EventRegister(e *waiter.Entry, mask waiter.EventMask) {
+	s.socketOpsCommon.EventRegister(e, mask)
+}
+
+// EventUnregister implements waiter.Waitable.EventUnregister.
+func (s *SocketVFS2) EventUnregister(e *waiter.Entry) {
+	s.socketOpsCommon.EventUnregister(e)
+}
+
+// SetSockOpt implements the linux syscall setsockopt(2) for sockets backed by
+// a transport.Endpoint.
+func (s *SocketVFS2) SetSockOpt(t *kernel.Task, level int, name int, optVal []byte) *syserr.Error {
+	return netstack.SetSockOpt(t, s, s.ep, level, name, optVal)
+}
+
+// LockPOSIX implements vfs.FileDescriptionImpl.LockPOSIX.
+func (s *SocketVFS2) LockPOSIX(ctx context.Context, uid fslock.UniqueID, t fslock.LockType, start, length uint64, whence int16, block fslock.Blocker) error {
+	return s.Locks().LockPOSIX(ctx, &s.vfsfd, uid, t, start, length, whence, block)
+}
+
+// UnlockPOSIX implements vfs.FileDescriptionImpl.UnlockPOSIX.
+func (s *SocketVFS2) UnlockPOSIX(ctx context.Context, uid fslock.UniqueID, start, length uint64, whence int16) error {
+	return s.Locks().UnlockPOSIX(ctx, &s.vfsfd, uid, start, length, whence)
+}
+
+// providerVFS2 is a unix domain socket provider for VFS2.
+type providerVFS2 struct{}
+
+func (*providerVFS2) Socket(t *kernel.Task, stype linux.SockType, protocol int) (*vfs.FileDescription, *syserr.Error) {
+	// Check arguments.
+	if protocol != 0 && protocol != linux.AF_UNIX /* PF_UNIX */ {
+		return nil, syserr.ErrProtocolNotSupported
+	}
+
+	// Create the endpoint and socket.
+	var ep transport.Endpoint
+	switch stype {
+	case linux.SOCK_DGRAM, linux.SOCK_RAW:
+		ep = transport.NewConnectionless(t)
+	case linux.SOCK_SEQPACKET, linux.SOCK_STREAM:
+		ep = transport.NewConnectioned(t, stype, t.Kernel())
+	default:
+		return nil, syserr.ErrInvalidArgument
+	}
+
+	f, err := NewSockfsFile(t, ep, stype)
+	if err != nil {
+		ep.Close(t)
+		return nil, err
+	}
+	return f, nil
+}
+
+// Pair creates a new pair of AF_UNIX connected sockets.
+func (*providerVFS2) Pair(t *kernel.Task, stype linux.SockType, protocol int) (*vfs.FileDescription, *vfs.FileDescription, *syserr.Error) {
+	// Check arguments.
+	if protocol != 0 && protocol != linux.AF_UNIX /* PF_UNIX */ {
+		return nil, nil, syserr.ErrProtocolNotSupported
+	}
+
+	switch stype {
+	case linux.SOCK_STREAM, linux.SOCK_DGRAM, linux.SOCK_SEQPACKET, linux.SOCK_RAW:
+		// Ok
+	default:
+		return nil, nil, syserr.ErrInvalidArgument
+	}
+
+	// Create the endpoints and sockets.
+	ep1, ep2 := transport.NewPair(t, stype, t.Kernel())
+	s1, err := NewSockfsFile(t, ep1, stype)
+	if err != nil {
+		ep1.Close(t)
+		ep2.Close(t)
+		return nil, nil, err
+	}
+	s2, err := NewSockfsFile(t, ep2, stype)
+	if err != nil {
+		s1.DecRef(t)
+		ep2.Close(t)
+		return nil, nil, err
+	}
+
+	return s1, s2, nil
+}