Merge pull request #105 from AkihiroSuda/dev-allow-exclude-home-ssh

ssh: allow `ssh.loadDotSSHPubKeys = false`

Author: AkihiroSuda

cmd/limactl/copy.go

@@ -36,7 +36,8 @@ func copyAction(clicontext *cli.Context) error {
 		return err
 	}
 
-	args, err := sshutil.CommonArgs()
+	const useDotSSH = true
+	args, err := sshutil.CommonArgs(useDotSSH)
 	if err != nil {
 		return err
 	}

cmd/limactl/shell.go

@@ -103,7 +103,7 @@ func shellAction(clicontext *cli.Context) error {
 		return err
 	}
 
-	args, err := sshutil.SSHArgs(inst.Dir)
+	args, err := sshutil.SSHArgs(inst.Dir, *y.SSH.LoadDotSSHPubKeys)
 	if err != nil {
 		return err
 	}

pkg/cidata/cidata.go

@@ -41,7 +41,7 @@ func GenerateISO9660(isoPath, name string, y *limayaml.LimaYAML) error {
 		Containerd: Containerd{System: *y.Containerd.System, User: *y.Containerd.User},
 	}
 
-	pubKeys, err := sshutil.DefaultPubKeys()
+	pubKeys, err := sshutil.DefaultPubKeys(*y.SSH.LoadDotSSHPubKeys)
 	if err != nil {
 		return err
 	}

pkg/hostagent/hostagent.go

@@ -66,6 +66,7 @@ func New(instName string, stdout, stderr io.Writer, sigintCh chan os.Signal) (*H
 	if err != nil {
 		return nil, err
 	}
+	// y is loaded with FillDefault() already, so no need to care about nil pointers.
 
 	qCfg := qemu.Config{
 		Name:        instName,
@@ -77,7 +78,7 @@ func New(instName string, stdout, stderr io.Writer, sigintCh chan os.Signal) (*H
 		return nil, err
 	}
 
-	sshArgs, err := sshutil.SSHArgs(inst.Dir)
+	sshArgs, err := sshutil.SSHArgs(inst.Dir, *y.SSH.LoadDotSSHPubKeys)
 	if err != nil {
 		return nil, err
 	}

pkg/limayaml/default.yaml

@@ -46,6 +46,12 @@ ssh:
   # Currently, this port number has to be specified manually.
   # Default: none
   localPort: 60022
+  # Load ~/.ssh/*.pub in addition to $LIMA_HOME/_config/user.pub .
+  # This option is useful when you want to use other SSH-based
+  # applications such as rsync with the Lima instance.
+  # If you have an insecure key under ~/.ssh, do not use this option.
+  # Default: true
+  loadDotSSHPubKeys: true
 
 firmware:
   # Use legacy BIOS instead of UEFI.

pkg/limayaml/defaults.go

@@ -25,6 +25,9 @@ func FillDefault(y *LimaYAML) {
 	if y.Video.Display == "" {
 		y.Video.Display = "none"
 	}
+	if y.SSH.LoadDotSSHPubKeys == nil {
+		y.SSH.LoadDotSSHPubKeys = &[]bool{true}[0]
+	}
 	for i := range y.Provision {
 		provision := &y.Provision[i]
 		if provision.Mode == "" {

pkg/limayaml/limayaml.go

@@ -34,6 +34,10 @@ type Mount struct {
 
 type SSH struct {
 	LocalPort int `yaml:"localPort,omitempty"` // REQUIRED (FIXME: auto assign)
+
+	// LoadDotSSHPubKeys loads ~/.ssh/*.pub in addition to $LIMA_HOME/_config/user.pub .
+	// Default: true
+	LoadDotSSHPubKeys *bool `yaml:"loadDotSSHPubKeys,omitempty"`
 }
 
 type Firmware struct {
@@ -60,8 +64,8 @@ type Provision struct {
 }
 
 type Containerd struct {
-	System *bool `yaml:"system,omitempty"`
-	User   *bool `yaml:"user,omitempty"`
+	System *bool `yaml:"system,omitempty"` // default: false
+	User   *bool `yaml:"user,omitempty"`   // default: true
 }
 
 type ProbeMode = string

pkg/sshutil/sshutil.go

@@ -35,10 +35,11 @@ func readPublicKey(f string) (PubKey, error) {
 }
 
 // DefaultPubKeys returns the public key from $LIMA_HOME/_config/user.pub.
-// The key will be created if it does not yet exist. All public keys
-// ~/.ssh/*.pub will be appended to make the VM accessible without specifying
-// and identity explicitly.
-func DefaultPubKeys() ([]PubKey, error) {
+// The key will be created if it does not yet exist.
+//
+// When loadDotSSH is true, ~/.ssh/*.pub will be appended to make the VM accessible without specifying
+// an identity explicitly.
+func DefaultPubKeys(loadDotSSH bool) ([]PubKey, error) {
 	// Read $LIMA_HOME/_config/user.pub
 	configDir, err := store.LimaConfigDir()
 	if err != nil {
@@ -70,6 +71,10 @@ func DefaultPubKeys() ([]PubKey, error) {
 	}
 	res := []PubKey{entry}
 
+	if !loadDotSSH {
+		return res, nil
+	}
+
 	// Append all of ~/.ssh/*.pub
 	homeDir, err := os.UserHomeDir()
 	if err != nil {
@@ -112,7 +117,7 @@ func RemoveKnownHostEntries(sshLocalPort int) error {
 	return nil
 }
 
-func CommonArgs() ([]string, error) {
+func CommonArgs(useDotSSH bool) ([]string, error) {
 	configDir, err := store.LimaConfigDir()
 	if err != nil {
 		return nil, err
@@ -126,24 +131,26 @@ func CommonArgs() ([]string, error) {
 
 	// Append all private keys corresponding to ~/.ssh/*.pub to keep old instances workin
 	// that had been created before lima started using an internal identity.
-	homeDir, err := os.UserHomeDir()
-	if err != nil {
-		return nil, err
-	}
-	files, err := filepath.Glob(filepath.Join(homeDir, ".ssh/*.pub"))
-	if err != nil {
-		panic(err) // Only possible error is ErrBadPattern, so this should be unreachable.
-	}
-	for _, f := range files {
-		if !strings.HasSuffix(f, ".pub") {
-			panic(errors.Errorf("unexpected ssh public key filename %q", f))
-		}
-		privateKeyPath := strings.TrimSuffix(f, ".pub")
-		_, err = os.Stat(privateKeyPath)
+	if useDotSSH {
+		homeDir, err := os.UserHomeDir()
 		if err != nil {
 			return nil, err
 		}
-		args = append(args, "-i", privateKeyPath)
+		files, err := filepath.Glob(filepath.Join(homeDir, ".ssh/*.pub"))
+		if err != nil {
+			panic(err) // Only possible error is ErrBadPattern, so this should be unreachable.
+		}
+		for _, f := range files {
+			if !strings.HasSuffix(f, ".pub") {
+				panic(errors.Errorf("unexpected ssh public key filename %q", f))
+			}
+			privateKeyPath := strings.TrimSuffix(f, ".pub")
+			_, err = os.Stat(privateKeyPath)
+			if err != nil {
+				return nil, err
+			}
+			args = append(args, "-i", privateKeyPath)
+		}
 	}
 
 	args = append(args,
@@ -157,7 +164,7 @@ func CommonArgs() ([]string, error) {
 	return args, nil
 }
 
-func SSHArgs(instDir string) ([]string, error) {
+func SSHArgs(instDir string, useDotSSH bool) ([]string, error) {
 	controlSock := filepath.Join(instDir, filenames.SSHSock)
 	if len(controlSock) >= osutil.UnixPathMax {
 		return nil, errors.Errorf("socket path %q is too long: >= UNIX_PATH_MAX=%d", controlSock, osutil.UnixPathMax)
@@ -166,7 +173,7 @@ func SSHArgs(instDir string) ([]string, error) {
 	if err != nil {
 		return nil, err
 	}
-	args, err := CommonArgs()
+	args, err := CommonArgs(useDotSSH)
 	if err != nil {
 		return nil, err
 	}

pkg/sshutil/sshutil_test.go

@@ -3,7 +3,7 @@ package sshutil
 import "testing"
 
 func TestDefaultPubKeys(t *testing.T) {
-	keys, _ := DefaultPubKeys()
+	keys, _ := DefaultPubKeys(true)
 	t.Logf("found %d public keys", len(keys))
 	for _, key := range keys {
 		t.Logf("%s: %q", key.Filename, key.Content)