Merge pull request #1699 from balajiv113/fix-path-size

Fix usernet socket name too long

Author: AkihiroSuda

pkg/networks/usernet/config.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"path/filepath"
 
+	"github.com/lima-vm/lima/pkg/osutil"
 	"github.com/lima-vm/lima/pkg/store/dirnames"
 )
 
@@ -12,7 +13,7 @@ type SockType = string
 const (
 	FDSock       = "fd"
 	QEMUSock     = "qemu"
-	EndpointSock = "endpoint"
+	EndpointSock = "ep"
 )
 
 // Sock returns a usernet socket based on name and sockType.
@@ -21,12 +22,20 @@ func Sock(name string, sockType SockType) (string, error) {
 	if err != nil {
 		return "", err
 	}
-	return SockWithDirectory(filepath.Join(dir, name), name, sockType), nil
+	return SockWithDirectory(filepath.Join(dir, name), name, sockType)
 }
 
 // SockWithDirectory return a usernet socket based on dir, name and sockType
-func SockWithDirectory(dir string, name string, sockType SockType) string {
-	return filepath.Join(dir, fmt.Sprintf("usernet_%s_%s.sock", name, sockType))
+func SockWithDirectory(dir string, name string, sockType SockType) (string, error) {
+	if name == "" {
+		name = "default"
+	}
+	sockPath := filepath.Join(dir, fmt.Sprintf("%s_%s.sock", name, sockType))
+	if len(sockPath) >= osutil.UnixPathMax {
+		return "", fmt.Errorf("usernet socket path %q too long: must be less than UNIX_PATH_MAX=%d characters, but is %d",
+			sockPath, osutil.UnixPathMax, len(sockPath))
+	}
+	return sockPath, nil
 }
 
 // PIDFile returns a path for usernet PID file

pkg/networks/usernet/config_test.go

@@ -0,0 +1,44 @@
+package usernet
+
+import (
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/lima-vm/lima/pkg/store/dirnames"
+	"github.com/lima-vm/lima/pkg/store/filenames"
+	"gotest.tools/v3/assert"
+)
+
+func TestConfig(t *testing.T) {
+	t.Run("max network path in instance directory", func(t *testing.T) {
+		limaHome, err := dirnames.LimaDir()
+		assert.NilError(t, err)
+		longName := strings.Repeat("a", len(filenames.LongestSock))
+		longestInstDir := filepath.Join(limaHome, longName)
+		_, err = SockWithDirectory(longestInstDir, longName, QEMUSock)
+		assert.NilError(t, err)
+	})
+
+	t.Run("max network path in _networks directory", func(t *testing.T) {
+		instName := strings.Repeat("a", len(filenames.LongestSock))
+		_, err := Sock(instName, EndpointSock)
+		assert.NilError(t, err)
+	})
+
+	t.Run("throw error for invalid socket path", func(t *testing.T) {
+		limaHome, err := dirnames.LimaDir()
+		assert.NilError(t, err)
+		longName := strings.Repeat("a", len(filenames.LongestSock))
+		longestInstDir := filepath.Join(limaHome, longName)
+		invalidName := strings.Repeat(longName, 4)
+		_, err = SockWithDirectory(longestInstDir, invalidName, QEMUSock)
+		assert.ErrorContains(t, err, "must be less than UNIX_PATH_MAX=")
+	})
+
+	t.Run("default as name when empty", func(t *testing.T) {
+		path, err := SockWithDirectory("test", "", QEMUSock)
+		assert.NilError(t, err)
+		assert.Equal(t, path, filepath.Join("test", "default_qemu.sock"))
+	})
+}

pkg/vz/vm_darwin.go

@@ -121,11 +121,17 @@ func startUsernet(ctx context.Context, driver *driver.BaseDriver) (*usernet.Clie
 	firstUsernetIndex := limayaml.FirstUsernetIndex(driver.Yaml)
 	if firstUsernetIndex == -1 {
 		//Start a in-process gvisor-tap-vsock
-		endpointSock := usernet.SockWithDirectory(driver.Instance.Dir, "", usernet.EndpointSock)
-		vzSock := usernet.SockWithDirectory(driver.Instance.Dir, "", usernet.FDSock)
+		endpointSock, err := usernet.SockWithDirectory(driver.Instance.Dir, "", usernet.EndpointSock)
+		if err != nil {
+			return nil, err
+		}
+		vzSock, err := usernet.SockWithDirectory(driver.Instance.Dir, "", usernet.FDSock)
+		if err != nil {
+			return nil, err
+		}
 		os.RemoveAll(endpointSock)
 		os.RemoveAll(vzSock)
-		err := usernet.StartGVisorNetstack(ctx, &usernet.GVisorNetstackOpts{
+		err = usernet.StartGVisorNetstack(ctx, &usernet.GVisorNetstackOpts{
 			MTU:      1500,
 			Endpoint: endpointSock,
 			FdSocket: vzSock,
@@ -278,7 +284,10 @@ func attachNetwork(driver *driver.BaseDriver, vmConfig *vz.VirtualMachineConfigu
 	firstUsernetIndex := limayaml.FirstUsernetIndex(driver.Yaml)
 	if firstUsernetIndex == -1 {
 		//slirp network using gvisor netstack
-		vzSock := usernet.SockWithDirectory(driver.Instance.Dir, "", usernet.FDSock)
+		vzSock, err := usernet.SockWithDirectory(driver.Instance.Dir, "", usernet.FDSock)
+		if err != nil {
+			return err
+		}
 		networkConn, err := PassFDToUnix(vzSock)
 		if err != nil {
 			return err