Merge cbf1c7fba6 into ea068414dc

* feat: validate ssh public key before saving

* fix: TestValidSSHKeyTypes

hidrpc.go

@@ -29,6 +29,8 @@ func handleHidRPCMessage(message hidrpc.Message, session *Session) {
 			session.reportHidRPCKeysDownState(*keysDownState)
 		}
 		rpcErr = err
+	case hidrpc.TypeKeypressKeepAliveReport:
+		gadget.DelayAutoRelease()
 	case hidrpc.TypePointerReport:
 		pointerReport, err := message.PointerReport()
 		if err != nil {
@@ -52,8 +54,13 @@ func handleHidRPCMessage(message hidrpc.Message, session *Session) {
 	}
 }
 
-func onHidMessage(data []byte, session *Session) {
+func onHidMessage(msg hidQueueMessage, session *Session) {
-	scopedLogger := hidRPCLogger.With().Bytes("data", data).Logger()
+	data := msg.Data
+
+	scopedLogger := hidRPCLogger.With().
+		Str("channel", msg.channel).
+		Bytes("data", data).
+		Logger()
 	scopedLogger.Debug().Msg("HID RPC message received")
 
 	if len(data) < 1 {

internal/hidrpc/hidrpc.go

@@ -15,6 +15,7 @@ const (
 	TypePointerReport           MessageType = 0x03
 	TypeWheelReport             MessageType = 0x04
 	TypeKeypressReport          MessageType = 0x05
+	TypeKeypressKeepAliveReport MessageType = 0x09
 	TypeMouseReport             MessageType = 0x06
 	TypeKeyboardLedState        MessageType = 0x32
 	TypeKeydownState            MessageType = 0x33
@@ -98,3 +99,11 @@ func NewKeydownStateMessage(state usbgadget.KeysDownState) *Message {
 		d: data,
 	}
 }
+
+// NewKeypressKeepAliveMessage creates a new keypress keep alive message.
+func NewKeypressKeepAliveMessage() *Message {
+	return &Message{
+		t: TypeKeypressKeepAliveReport,
+		d: []byte{},
+	}
+}

internal/hidrpc/message.go

@@ -43,6 +43,8 @@ func (m *Message) String() string {
 			return fmt.Sprintf("MouseReport{Malformed: %v}", m.d)
 		}
 		return fmt.Sprintf("MouseReport{DX: %d, DY: %d, Button: %d}", m.d[0], m.d[1], m.d[2])
+	case TypeKeypressKeepAliveReport:
+		return "KeypressKeepAliveReport"
 	default:
 		return fmt.Sprintf("Unknown{Type: %d, Data: %v}", m.t, m.d)
 	}

internal/usbgadget/hid_keyboard.go

@@ -22,6 +22,11 @@ var keyboardConfig = gadgetConfigItem{
 	reportDesc: keyboardReportDesc,
 }
 
+// macOS default: 15 * 15 = 225ms https://discussions.apple.com/thread/1316947?sortBy=rank
+// Linux default: 250ms https://man.archlinux.org/man/kbdrate.8.en
+// Windows default: 1ms `HKEY_CURRENT_USER\Control Panel\Accessibility\Keyboard Response\AutoRepeatDelay`
+const autoReleaseKeyboardInterval = time.Millisecond * 225
+
 // Source: https://www.kernel.org/doc/Documentation/usb/gadget_hid.txt
 var keyboardReportDesc = []byte{
 	0x05, 0x01, /* USAGE_PAGE (Generic Desktop)	          */
@@ -173,6 +178,64 @@ func (u *UsbGadget) SetOnKeysDownChange(f func(state KeysDownState)) {
 	u.onKeysDownChange = &f
 }
 
+func (u *UsbGadget) scheduleAutoRelease(key byte) {
+	u.kbdAutoReleaseLock.Lock()
+	defer u.kbdAutoReleaseLock.Unlock()
+
+	if u.kbdAutoReleaseTimer != nil {
+		u.kbdAutoReleaseTimer.Stop()
+	}
+
+	u.kbdAutoReleaseTimer = time.AfterFunc(autoReleaseKeyboardInterval, func() {
+		u.performAutoRelease(key)
+	})
+}
+
+func (u *UsbGadget) cancelAutoRelease() {
+	u.kbdAutoReleaseLock.Lock()
+	defer u.kbdAutoReleaseLock.Unlock()
+
+	if u.kbdAutoReleaseTimer != nil {
+		u.kbdAutoReleaseTimer.Stop()
+	}
+}
+
+func (u *UsbGadget) DelayAutoRelease() {
+	u.kbdAutoReleaseLock.Lock()
+	defer u.kbdAutoReleaseLock.Unlock()
+
+	u.log.Trace().Msg("delaying auto-release")
+
+	if u.kbdAutoReleaseTimer == nil {
+		return
+	}
+
+	u.kbdAutoReleaseTimer.Reset(autoReleaseKeyboardInterval)
+
+	u.log.Trace().Msg("auto-release timer reset")
+}
+
+func (u *UsbGadget) performAutoRelease(key byte) {
+	u.kbdAutoReleaseLock.Lock()
+	defer u.kbdAutoReleaseLock.Unlock()
+
+	select {
+	case <-u.keyboardStateCtx.Done():
+		return
+	default:
+	}
+
+	// we just reset the keyboard state to 0 no matter what
+	_, err := u.keypressReport(0, false, false)
+	if err != nil {
+		u.log.Warn().Uint8("key", key).Msg("failed to auto-release keyboard key")
+	}
+
+	u.kbdAutoReleaseTimer = nil
+
+	u.log.Trace().Uint8("key", key).Msg("auto release performed")
+}
+
 func (u *UsbGadget) listenKeyboardEvents() {
 	var path string
 	if u.keyboardHidFile != nil {
@@ -331,9 +394,10 @@ var KeyCodeToMaskMap = map[byte]byte{
 	RightSuper:   ModifierMaskRightSuper,
 }
 
-func (u *UsbGadget) KeypressReport(key byte, press bool) (KeysDownState, error) {
+func (u *UsbGadget) keypressReport(key byte, press bool, autoRelease bool) (KeysDownState, error) {
 	u.keyboardLock.Lock()
 	defer u.keyboardLock.Unlock()
+
 	defer u.resetUserInputTime()
 
 	// IMPORTANT: This code parallels the logic in the kernel's hid-gadget driver
@@ -398,5 +462,25 @@ func (u *UsbGadget) KeypressReport(key byte, press bool) (KeysDownState, error)
 		u.log.Warn().Uint8("modifier", modifier).Uints8("keys", keys).Msg("Could not write keypress report to hidg0")
 	}
 
+	if press {
+		{
+			u.kbdAutoReleaseLock.Lock()
+			u.kbdAutoReleaseLastKey = key
+			u.kbdAutoReleaseLock.Unlock()
+		}
+
+		if autoRelease {
+			u.scheduleAutoRelease(key)
+		}
+	} else {
+		if autoRelease {
+			u.cancelAutoRelease()
+		}
+	}
+
 	return u.UpdateKeysDown(modifier, keys), err
 }
+
+func (u *UsbGadget) KeypressReport(key byte, press bool) (KeysDownState, error) {
+	return u.keypressReport(key, press, true)
+}

internal/usbgadget/usbgadget.go

@@ -68,6 +68,10 @@ type UsbGadget struct {
 	keyboardState byte          // keyboard latched state (NumLock, CapsLock, ScrollLock, Compose, Kana)
 	keysDownState KeysDownState // keyboard dynamic state (modifier keys and pressed keys)
 
+	kbdAutoReleaseLock    sync.Mutex
+	kbdAutoReleaseTimer   *time.Timer
+	kbdAutoReleaseLastKey byte
+
 	keyboardStateLock   sync.Mutex
 	keyboardStateCtx    context.Context
 	keyboardStateCancel context.CancelFunc
@@ -149,3 +153,35 @@ func newUsbGadget(name string, configMap map[string]gadgetConfigItem, enabledDev
 
 	return g
 }
+
+// Close cleans up resources used by the USB gadget
+func (u *UsbGadget) Close() error {
+	// Cancel keyboard state context
+	if u.keyboardStateCancel != nil {
+		u.keyboardStateCancel()
+	}
+
+	// Stop auto-release timer
+	u.kbdAutoReleaseLock.Lock()
+	if u.kbdAutoReleaseTimer != nil {
+		u.kbdAutoReleaseTimer.Stop()
+		u.kbdAutoReleaseTimer = nil
+	}
+	u.kbdAutoReleaseLock.Unlock()
+
+	// Close HID files
+	if u.keyboardHidFile != nil {
+		u.keyboardHidFile.Close()
+		u.keyboardHidFile = nil
+	}
+	if u.absMouseHidFile != nil {
+		u.absMouseHidFile.Close()
+		u.absMouseHidFile = nil
+	}
+	if u.relMouseHidFile != nil {
+		u.relMouseHidFile.Close()
+		u.relMouseHidFile = nil
+	}
+
+	return nil
+}

internal/utils/ssh.go

@@ -0,0 +1,71 @@
+package utils
+
+import (
+	"fmt"
+	"slices"
+	"strings"
+
+	"golang.org/x/crypto/ssh"
+)
+
+// ValidSSHKeyTypes is a list of valid SSH key types
+//
+// Please make sure that all the types in this list are supported by dropbear
+// https://github.com/mkj/dropbear/blob/003c5fcaabc114430d5d14142e95ffdbbd2d19b6/src/signkey.c#L37
+//
+// ssh-dss is not allowed here as it's insecure
+var ValidSSHKeyTypes = []string{
+	ssh.KeyAlgoRSA,
+	ssh.KeyAlgoED25519,
+	ssh.KeyAlgoECDSA256,
+	ssh.KeyAlgoECDSA384,
+	ssh.KeyAlgoECDSA521,
+}
+
+// ValidateSSHKey validates authorized_keys file content
+func ValidateSSHKey(sshKey string) error {
+	// validate SSH key
+	var (
+		hasValidPublicKey = false
+		lastError         = fmt.Errorf("no valid SSH key found")
+	)
+	for _, key := range strings.Split(sshKey, "\n") {
+		key = strings.TrimSpace(key)
+
+		// skip empty lines and comments
+		if key == "" || strings.HasPrefix(key, "#") {
+			continue
+		}
+
+		parsedPublicKey, _, _, _, err := ssh.ParseAuthorizedKey([]byte(key))
+		if err != nil {
+			lastError = err
+			continue
+		}
+
+		if parsedPublicKey == nil {
+			continue
+		}
+
+		parsedType := parsedPublicKey.Type()
+		textType := strings.Fields(key)[0]
+
+		if parsedType != textType {
+			lastError = fmt.Errorf("parsed SSH key type %s does not match type in text %s", parsedType, textType)
+			continue
+		}
+
+		if !slices.Contains(ValidSSHKeyTypes, parsedType) {
+			lastError = fmt.Errorf("invalid SSH key type: %s", parsedType)
+			continue
+		}
+
+		hasValidPublicKey = true
+	}
+
+	if !hasValidPublicKey {
+		return lastError
+	}
+
+	return nil
+}

internal/utils/ssh_test.go

@@ -0,0 +1,208 @@
+package utils
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestValidateSSHKey(t *testing.T) {
+	tests := []struct {
+		name        string
+		sshKey      string
+		expectError bool
+		errorMsg    string
+	}{
+		{
+			name:        "valid RSA key",
+			sshKey:      "ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDiYUb9Fy2vlPfO+HwubnshimpVrWPoePyvyN+jPC5gWqZSycjMy6Is2vFVn7oQc72bkY0wZalspT5wUOwKtltSoLpL7vcqGL9zHVw4yjYXtPGIRd3zLpU9wdngevnepPQWTX3LvZTZfmOsrGoMDKIG+Lbmiq/STMuWYecIqMp7tUKRGS8vfAmpu6MsrN9/4UTcdWWXYWJQQn+2nCyMz28jYlWRsKtqFK6owrdZWt8WQnPN+9Upcf2ByQje+0NLnpNrnh+yd2ocuVW9wQYKAZXy7IaTfEJwd5m34sLwkqlZTaBBcmWJU+3RfpYXE763cf3rUoPIGQ8eUEBJ8IdM4vhp test@example.com",
+			expectError: false,
+		},
+		{
+			name:        "valid ED25519 key",
+			sshKey:      "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIBSbM8wuD5ab0nHsXaYOqaD3GLLUwmDzSk79Xi/N+H2j test@example.com",
+			expectError: false,
+		},
+		{
+			name:        "valid ECDSA key",
+			sshKey:      "ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBAlTkxIo4mXBR+gEX0Q74BpYX4bFFHoX+8Uz7tsob8HvsnMvsEE+BW9h9XrbWX4/4ppL/o6sHbvsqNr9HcyKfdc= test@example.com",
+			expectError: false,
+		},
+		{
+			name:        "multiple valid keys",
+			sshKey:      "ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDiYUb9Fy2vlPfO+HwubnshimpVrWPoePyvyN+jPC5gWqZSycjMy6Is2vFVn7oQc72bkY0wZalspT5wUOwKtltSoLpL7vcqGL9zHVw4yjYXtPGIRd3zLpU9wdngevnepPQWTX3LvZTZfmOsrGoMDKIG+Lbmiq/STMuWYecIqMp7tUKRGS8vfAmpu6MsrN9/4UTcdWWXYWJQQn+2nCyMz28jYlWRsKtqFK6owrdZWt8WQnPN+9Upcf2ByQje+0NLnpNrnh+yd2ocuVW9wQYKAZXy7IaTfEJwd5m34sLwkqlZTaBBcmWJU+3RfpYXE763cf3rUoPIGQ8eUEBJ8IdM4vhp test@example.com\nssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIBSbM8wuD5ab0nHsXaYOqaD3GLLUwmDzSk79Xi/N+H2j test@example.com",
+			expectError: false,
+		},
+		{
+			name:        "valid key with comment",
+			sshKey:      "ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDiYUb9Fy2vlPfO+HwubnshimpVrWPoePyvyN+jPC5gWqZSycjMy6Is2vFVn7oQc72bkY0wZalspT5wUOwKtltSoLpL7vcqGL9zHVw4yjYXtPGIRd3zLpU9wdngevnepPQWTX3LvZTZfmOsrGoMDKIG+Lbmiq/STMuWYecIqMp7tUKRGS8vfAmpu6MsrN9/4UTcdWWXYWJQQn+2nCyMz28jYlWRsKtqFK6owrdZWt8WQnPN+9Upcf2ByQje+0NLnpNrnh+yd2ocuVW9wQYKAZXy7IaTfEJwd5m34sLwkqlZTaBBcmWJU+3RfpYXE763cf3rUoPIGQ8eUEBJ8IdM4vhp user@example.com",
+			expectError: false,
+		},
+		{
+			name:        "valid key with options and comment (we don't support options yet)",
+			sshKey:      "command=\"echo hello\" ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDiYUb9Fy2vlPfO+HwubnshimpVrWPoePyvyN+jPC5gWqZSycjMy6Is2vFVn7oQc72bkY0wZalspT5wUOwKtltSoLpL7vcqGL9zHVw4yjYXtPGIRd3zLpU9wdngevnepPQWTX3LvZTZfmOsrGoMDKIG+Lbmiq/STMuWYecIqMp7tUKRGS8vfAmpu6MsrN9/4UTcdWWXYWJQQn+2nCyMz28jYlWRsKtqFK6owrdZWt8WQnPN+9Upcf2ByQje+0NLnpNrnh+yd2ocuVW9wQYKAZXy7IaTfEJwd5m34sLwkqlZTaBBcmWJU+3RfpYXE763cf3rUoPIGQ8eUEBJ8IdM4vhp user@example.com",
+			expectError: true,
+		},
+		{
+			name:        "empty string",
+			sshKey:      "",
+			expectError: true,
+			errorMsg:    "no valid SSH key found",
+		},
+		{
+			name:        "whitespace only",
+			sshKey:      "   \n\t  \n  ",
+			expectError: true,
+			errorMsg:    "no valid SSH key found",
+		},
+		{
+			name:        "comment only",
+			sshKey:      "# This is a comment\n# Another comment",
+			expectError: true,
+			errorMsg:    "no valid SSH key found",
+		},
+		{
+			name:        "invalid key format",
+			sshKey:      "not-a-valid-ssh-key",
+			expectError: true,
+		},
+		{
+			name:        "invalid key type",
+			sshKey:      "ssh-dss AAAAB3NzaC1kc3MAAACBAOeB...",
+			expectError: true,
+			errorMsg:    "invalid SSH key type: ssh-dss",
+		},
+		{
+			name:        "unsupported key type",
+			sshKey:      "ssh-rsa-cert-v01@openssh.com AAAAB3NzaC1yc2EAAAADAQABAAABgQC7vbqajDhA...",
+			expectError: true,
+			errorMsg:    "invalid SSH key type: ssh-rsa-cert-v01@openssh.com",
+		},
+		{
+			name:        "malformed key data",
+			sshKey:      "ssh-rsa invalid-base64-data",
+			expectError: true,
+		},
+		{
+			name:        "type mismatch",
+			sshKey:      "ssh-rsa AAAAC3NzaC1lZDI1NTE5AAAAIGomKoH...",
+			expectError: true,
+			errorMsg:    "parsed SSH key type ssh-ed25519 does not match type in text ssh-rsa",
+		},
+		{
+			name:        "mixed valid and invalid keys",
+			sshKey:      "ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDiYUb9Fy2vlPfO+HwubnshimpVrWPoePyvyN+jPC5gWqZSycjMy6Is2vFVn7oQc72bkY0wZalspT5wUOwKtltSoLpL7vcqGL9zHVw4yjYXtPGIRd3zLpU9wdngevnepPQWTX3LvZTZfmOsrGoMDKIG+Lbmiq/STMuWYecIqMp7tUKRGS8vfAmpu6MsrN9/4UTcdWWXYWJQQn+2nCyMz28jYlWRsKtqFK6owrdZWt8WQnPN+9Upcf2ByQje+0NLnpNrnh+yd2ocuVW9wQYKAZXy7IaTfEJwd5m34sLwkqlZTaBBcmWJU+3RfpYXE763cf3rUoPIGQ8eUEBJ8IdM4vhp test@example.com\ninvalid-key\nssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIBSbM8wuD5ab0nHsXaYOqaD3GLLUwmDzSk79Xi/N+H2j test@example.com",
+			expectError: false,
+		},
+		{
+			name:        "valid key with empty lines and comments",
+			sshKey:      "# Comment line\n\nssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDiYUb9Fy2vlPfO+HwubnshimpVrWPoePyvyN+jPC5gWqZSycjMy6Is2vFVn7oQc72bkY0wZalspT5wUOwKtltSoLpL7vcqGL9zHVw4yjYXtPGIRd3zLpU9wdngevnepPQWTX3LvZTZfmOsrGoMDKIG+Lbmiq/STMuWYecIqMp7tUKRGS8vfAmpu6MsrN9/4UTcdWWXYWJQQn+2nCyMz28jYlWRsKtqFK6owrdZWt8WQnPN+9Upcf2ByQje+0NLnpNrnh+yd2ocuVW9wQYKAZXy7IaTfEJwd5m34sLwkqlZTaBBcmWJU+3RfpYXE763cf3rUoPIGQ8eUEBJ8IdM4vhp test@example.com\n# Another comment\n\t\n",
+			expectError: false,
+		},
+		{
+			name:        "all invalid keys",
+			sshKey:      "invalid-key-1\ninvalid-key-2\nssh-dss AAAAB3NzaC1kc3MAAACBAOeB...",
+			expectError: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			err := ValidateSSHKey(tt.sshKey)
+
+			if tt.expectError {
+				if err == nil {
+					t.Errorf("ValidateSSHKey() expected error but got none")
+				} else if tt.errorMsg != "" && !strings.ContainsAny(err.Error(), tt.errorMsg) {
+					t.Errorf("ValidateSSHKey() error = %v, expected to contain %v", err, tt.errorMsg)
+				}
+			} else {
+				if err != nil {
+					t.Errorf("ValidateSSHKey() unexpected error = %v", err)
+				}
+			}
+		})
+	}
+}
+
+func TestValidSSHKeyTypes(t *testing.T) {
+	expectedTypes := []string{
+		"ssh-rsa",
+		"ssh-ed25519",
+		"ecdsa-sha2-nistp256",
+		"ecdsa-sha2-nistp384",
+		"ecdsa-sha2-nistp521",
+	}
+
+	if len(ValidSSHKeyTypes) != len(expectedTypes) {
+		t.Errorf("ValidSSHKeyTypes length = %d, expected %d", len(ValidSSHKeyTypes), len(expectedTypes))
+	}
+
+	for _, expectedType := range expectedTypes {
+		found := false
+		for _, actualType := range ValidSSHKeyTypes {
+			if actualType == expectedType {
+				found = true
+				break
+			}
+		}
+		if !found {
+			t.Errorf("ValidSSHKeyTypes missing expected type: %s", expectedType)
+		}
+	}
+}
+
+// TestValidateSSHKeyEdgeCases tests edge cases and boundary conditions
+func TestValidateSSHKeyEdgeCases(t *testing.T) {
+	tests := []struct {
+		name        string
+		sshKey      string
+		expectError bool
+	}{
+		{
+			name:        "key with only type",
+			sshKey:      "ssh-rsa",
+			expectError: true,
+		},
+		{
+			name:        "key with type and empty data",
+			sshKey:      "ssh-rsa ",
+			expectError: true,
+		},
+		{
+			name:        "key with type and whitespace data",
+			sshKey:      "ssh-rsa   \t  ",
+			expectError: true,
+		},
+		{
+			name:        "key with multiple spaces between type and data",
+			sshKey:      "ssh-rsa    AAAAB3NzaC1yc2EAAAADAQABAAABAQDiYUb9Fy2vlPfO+HwubnshimpVrWPoePyvyN+jPC5gWqZSycjMy6Is2vFVn7oQc72bkY0wZalspT5wUOwKtltSoLpL7vcqGL9zHVw4yjYXtPGIRd3zLpU9wdngevnepPQWTX3LvZTZfmOsrGoMDKIG+Lbmiq/STMuWYecIqMp7tUKRGS8vfAmpu6MsrN9/4UTcdWWXYWJQQn+2nCyMz28jYlWRsKtqFK6owrdZWt8WQnPN+9Upcf2ByQje+0NLnpNrnh+yd2ocuVW9wQYKAZXy7IaTfEJwd5m34sLwkqlZTaBBcmWJU+3RfpYXE763cf3rUoPIGQ8eUEBJ8IdM4vhp test@example.com",
+			expectError: false,
+		},
+		{
+			name:        "key with tabs",
+			sshKey:      "\tssh-rsa\tAAAAB3NzaC1yc2EAAAADAQABAAABAQDiYUb9Fy2vlPfO+HwubnshimpVrWPoePyvyN+jPC5gWqZSycjMy6Is2vFVn7oQc72bkY0wZalspT5wUOwKtltSoLpL7vcqGL9zHVw4yjYXtPGIRd3zLpU9wdngevnepPQWTX3LvZTZfmOsrGoMDKIG+Lbmiq/STMuWYecIqMp7tUKRGS8vfAmpu6MsrN9/4UTcdWWXYWJQQn+2nCyMz28jYlWRsKtqFK6owrdZWt8WQnPN+9Upcf2ByQje+0NLnpNrnh+yd2ocuVW9wQYKAZXy7IaTfEJwd5m34sLwkqlZTaBBcmWJU+3RfpYXE763cf3rUoPIGQ8eUEBJ8IdM4vhp test@example.com",
+			expectError: false,
+		},
+		{
+			name:        "very long line",
+			sshKey:      "ssh-rsa " + string(make([]byte, 10000)),
+			expectError: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			err := ValidateSSHKey(tt.sshKey)
+
+			if tt.expectError {
+				if err == nil {
+					t.Errorf("ValidateSSHKey() expected error but got none")
+				}
+			} else {
+				if err != nil {
+					t.Errorf("ValidateSSHKey() unexpected error = %v", err)
+				}
+			}
+		})
+	}
+}

jsonrpc.go

@@ -17,6 +17,7 @@ import (
 	"go.bug.st/serial"
 
 	"github.com/jetkvm/kvm/internal/usbgadget"
+	"github.com/jetkvm/kvm/internal/utils"
 )
 
 type JSONRPCRequest struct {
@@ -429,7 +430,19 @@ func rpcGetSSHKeyState() (string, error) {
 }
 
 func rpcSetSSHKeyState(sshKey string) error {
-	if sshKey != "" {
+	if sshKey == "" {
+		// Remove SSH key file if empty string is provided
+		if err := os.Remove(sshKeyFile); err != nil && !os.IsNotExist(err) {
+			return fmt.Errorf("failed to remove SSH key file: %w", err)
+		}
+		return nil
+	}
+
+	// Validate SSH key
+	if err := utils.ValidateSSHKey(sshKey); err != nil {
+		return err
+	}
+
 	// Create directory if it doesn't exist
 	if err := os.MkdirAll(sshKeyDir, 0700); err != nil {
 		return fmt.Errorf("failed to create SSH key directory: %w", err)
@@ -439,12 +452,6 @@ func rpcSetSSHKeyState(sshKey string) error {
 	if err := os.WriteFile(sshKeyFile, []byte(sshKey), 0600); err != nil {
 		return fmt.Errorf("failed to write SSH key: %w", err)
 	}
-	} else {
-		// Remove SSH key file if empty string is provided
-		if err := os.Remove(sshKeyFile); err != nil && !os.IsNotExist(err) {
-			return fmt.Errorf("failed to remove SSH key file: %w", err)
-		}
-	}
 
 	return nil
 }

ui/src/components/USBStateStatus.tsx

@@ -22,14 +22,6 @@ const USBStateMap: Record<USBStates, string> = {
   "not attached": "Disconnected",
   suspended: "Low power mode",
 };
-
-export default function USBStateStatus({
-  state,
-  peerConnectionState,
-}: {
-  state: USBStates;
-  peerConnectionState?: RTCPeerConnectionState | null;
-}) {
 const StatusCardProps: StatusProps = {
   configured: {
     icon: ({ className }) => (
@@ -63,6 +55,15 @@ export default function USBStateStatus({
     statusIndicatorClassName: "bg-green-500 border-green-600",
   },
 };
+
+export default function USBStateStatus({
+  state,
+  peerConnectionState,
+}: {
+  state: USBStates;
+  peerConnectionState?: RTCPeerConnectionState | null;
+}) {
+
   const props = StatusCardProps[state];
   if (!props) {
     console.warn("Unsupported USB state: ", state);

ui/src/hooks/hidRpc.ts

@@ -6,6 +6,7 @@ export const HID_RPC_MESSAGE_TYPES = {
     PointerReport: 0x03,
     WheelReport: 0x04,
     KeypressReport: 0x05,
+    KeypressKeepAliveReport: 0x09,
     MouseReport: 0x06,
     KeyboardLedState: 0x32,
     KeysDownState: 0x33,
@@ -278,12 +279,23 @@ export class MouseReportMessage extends RpcMessage {
     }
 }
 
+export class KeypressKeepAliveMessage extends RpcMessage {
+    constructor() {
+        super(HID_RPC_MESSAGE_TYPES.KeypressKeepAliveReport);
+    }
+
+    marshal(): Uint8Array {
+        return new Uint8Array([this.messageType]);
+    }
+}
+
 export const messageRegistry = {
     [HID_RPC_MESSAGE_TYPES.Handshake]: HandshakeMessage,
     [HID_RPC_MESSAGE_TYPES.KeysDownState]: KeysDownStateMessage,
     [HID_RPC_MESSAGE_TYPES.KeyboardLedState]: KeyboardLedStateMessage,
     [HID_RPC_MESSAGE_TYPES.KeyboardReport]: KeyboardReportMessage,
     [HID_RPC_MESSAGE_TYPES.KeypressReport]: KeypressReportMessage,
+    [HID_RPC_MESSAGE_TYPES.KeypressKeepAliveReport]: KeypressKeepAliveMessage,
 }
 
 export const unmarshalHidRpcMessage = (data: Uint8Array): RpcMessage | undefined => {

ui/src/hooks/stores.ts

@@ -111,6 +111,12 @@ export interface RTCState {
   rpcHidChannel: RTCDataChannel | null;
   setRpcHidChannel: (channel: RTCDataChannel) => void;
 
+  rpcHidUnreliableChannel: RTCDataChannel | null;
+  setRpcHidUnreliableChannel: (channel: RTCDataChannel) => void;
+
+  rpcHidUnreliableNonOrderedChannel: RTCDataChannel | null;
+  setRpcHidUnreliableNonOrderedChannel: (channel: RTCDataChannel) => void;
+
   peerConnectionState: RTCPeerConnectionState | null;
   setPeerConnectionState: (state: RTCPeerConnectionState) => void;
 
@@ -163,6 +169,12 @@ export const useRTCStore = create<RTCState>(set => ({
   rpcHidChannel: null,
   setRpcHidChannel: (channel: RTCDataChannel) => set({ rpcHidChannel: channel }),
 
+  rpcHidUnreliableChannel: null,
+  setRpcHidUnreliableChannel: (channel: RTCDataChannel) => set({ rpcHidUnreliableChannel: channel }),
+
+  rpcHidUnreliableNonOrderedChannel: null,
+  setRpcHidUnreliableNonOrderedChannel: (channel: RTCDataChannel) => set({ rpcHidUnreliableNonOrderedChannel: channel }),
+
   transceiver: null,
   setTransceiver: (transceiver: RTCRtpTransceiver) => set({ transceiver }),
 

ui/src/hooks/useHidRpc.ts

@@ -6,6 +6,7 @@ import {
   HID_RPC_VERSION,
   HandshakeMessage,
   KeyboardReportMessage,
+  KeypressKeepAliveMessage,
   KeypressReportMessage,
   MouseReportMessage,
   PointerReportMessage,
@@ -13,20 +14,43 @@ import {
   unmarshalHidRpcMessage,
 } from "./hidRpc";
 
+const KEEPALIVE_MESSAGE = new KeypressKeepAliveMessage();
+
+interface sendMessageParams {
+  ignoreHandshakeState?: boolean;
+  useUnreliableChannel?: boolean;
+  requireOrdered?: boolean;
+}
+
 export function useHidRpc(onHidRpcMessage?: (payload: RpcMessage) => void) {
-  const { rpcHidChannel, setRpcHidProtocolVersion, rpcHidProtocolVersion } = useRTCStore();
+  const {
+    rpcHidChannel,
+    rpcHidUnreliableChannel,
+    rpcHidUnreliableNonOrderedChannel,
+    setRpcHidProtocolVersion,
+    rpcHidProtocolVersion,
+  } = useRTCStore();
+
   const rpcHidReady = useMemo(() => {
     return rpcHidChannel?.readyState === "open" && rpcHidProtocolVersion !== null;
   }, [rpcHidChannel, rpcHidProtocolVersion]);
 
+  const rpcHidUnreliableReady = useMemo(() => {
+    return rpcHidUnreliableChannel?.readyState === "open" && rpcHidProtocolVersion !== null;
+  }, [rpcHidUnreliableChannel, rpcHidProtocolVersion]);
+
+  const rpcHidUnreliableNonOrderedReady = useMemo(() => {
+    return rpcHidUnreliableNonOrderedChannel?.readyState === "open" && rpcHidProtocolVersion !== null;
+  }, [rpcHidUnreliableNonOrderedChannel, rpcHidProtocolVersion]);
+
   const rpcHidStatus = useMemo(() => {
     if (!rpcHidChannel) return "N/A";
     if (rpcHidChannel.readyState !== "open") return rpcHidChannel.readyState;
     if (!rpcHidProtocolVersion) return "handshaking";
-    return `ready (v${rpcHidProtocolVersion})`;
+    return `ready (v${rpcHidProtocolVersion}${rpcHidUnreliableReady ? "+u" : ""})`;
-  }, [rpcHidChannel, rpcHidProtocolVersion]);
+  }, [rpcHidChannel, rpcHidUnreliableReady, rpcHidProtocolVersion]);
 
-  const sendMessage = useCallback((message: RpcMessage, ignoreHandshakeState = false) => {
+  const sendMessage = useCallback((message: RpcMessage, { ignoreHandshakeState, useUnreliableChannel, requireOrdered = true }: sendMessageParams = {}) => {
     if (rpcHidChannel?.readyState !== "open") return;
     if (!rpcHidReady && !ignoreHandshakeState) return;
 
@@ -38,8 +62,24 @@ export function useHidRpc(onHidRpcMessage?: (payload: RpcMessage) => void) {
     }
     if (!data) return;
 
+    if (useUnreliableChannel) {
+      if (requireOrdered && rpcHidUnreliableReady) {
+        rpcHidUnreliableChannel?.send(data as unknown as ArrayBuffer);
+      } else if (!requireOrdered && rpcHidUnreliableNonOrderedReady) {
+        rpcHidUnreliableNonOrderedChannel?.send(data as unknown as ArrayBuffer);
+      }
+      return;
+    }
+
     rpcHidChannel?.send(data as unknown as ArrayBuffer);
-  }, [rpcHidChannel, rpcHidReady]);
+  }, [
+    rpcHidChannel,
+    rpcHidUnreliableChannel,
+    rpcHidUnreliableNonOrderedChannel,
+    rpcHidReady,
+    rpcHidUnreliableReady,
+    rpcHidUnreliableNonOrderedReady,
+  ]);
 
   const reportKeyboardEvent = useCallback(
     (keys: number[], modifier: number) => {
@@ -56,7 +96,7 @@ export function useHidRpc(onHidRpcMessage?: (payload: RpcMessage) => void) {
 
   const reportAbsMouseEvent = useCallback(
     (x: number, y: number, buttons: number) => {
-      sendMessage(new PointerReportMessage(x, y, buttons));
+      sendMessage(new PointerReportMessage(x, y, buttons), { useUnreliableChannel: true });
     },
     [sendMessage],
   );
@@ -68,11 +108,15 @@ export function useHidRpc(onHidRpcMessage?: (payload: RpcMessage) => void) {
     [sendMessage],
   );
 
+  const reportKeypressKeepAlive = useCallback(() => {
+    sendMessage(KEEPALIVE_MESSAGE, { useUnreliableChannel: true, requireOrdered: false });
+  }, [sendMessage]);
+
   const sendHandshake = useCallback(() => {
     if (rpcHidProtocolVersion) return;
     if (!rpcHidChannel) return;
 
-    sendMessage(new HandshakeMessage(HID_RPC_VERSION), true);
+    sendMessage(new HandshakeMessage(HID_RPC_VERSION), { ignoreHandshakeState: true });
   }, [rpcHidChannel, rpcHidProtocolVersion, sendMessage]);
 
   const handleHandshake = useCallback((message: HandshakeMessage) => {
@@ -143,6 +187,7 @@ export function useHidRpc(onHidRpcMessage?: (payload: RpcMessage) => void) {
     reportKeypressEvent,
     reportAbsMouseEvent,
     reportRelMouseEvent,
+    reportKeypressKeepAlive,
     rpcHidProtocolVersion,
     rpcHidReady,
     rpcHidStatus,

ui/src/hooks/useKeyboard.ts

@@ -1,4 +1,4 @@
-import { useCallback } from "react";
+import { useCallback, useRef } from "react";
 
 import { hidErrorRollOver, hidKeyBufferSize, KeysDownState, useHidStore, useRTCStore } from "@/hooks/stores";
 import { JsonRpcResponse, useJsonRpc } from "@/hooks/useJsonRpc";
@@ -11,6 +11,9 @@ export default function useKeyboard() {
   const { rpcDataChannel } = useRTCStore();
   const { keysDownState, setKeysDownState, setKeyboardLedState } = useHidStore();
 
+  // Keepalive timer management
+  const keepAliveTimerRef = useRef<number | null>(null);
+
   // INTRODUCTION: The earlier version of the JetKVM device shipped with all keyboard state
   // being tracked on the browser/client-side. When adding the keyPressReport API to the
   // device-side code, we have to still support the situation where the browser/client-side code
@@ -26,6 +29,7 @@ export default function useKeyboard() {
   const {
     reportKeyboardEvent: sendKeyboardEventHidRpc,
     reportKeypressEvent: sendKeypressEventHidRpc,
+    reportKeypressKeepAlive: sendKeypressKeepAliveHidRpc,
     rpcHidReady,
   } = useHidRpc((message) => {
     switch (message.constructor) {
@@ -70,17 +74,6 @@ export default function useKeyboard() {
     ],
   );
 
-  // resetKeyboardState is used to reset the keyboard state to no keys pressed and no modifiers.
-  // This is useful for macros and when the browser loses focus to ensure that the keyboard state
-  // is clean.
-  const resetKeyboardState = useCallback(
-    async () => {
-      // Reset the keys buffer to zeros and the modifier state to zero
-      keysDownState.keys.length = hidKeyBufferSize;
-      keysDownState.keys.fill(0);
-      keysDownState.modifier = 0;
-      sendKeyboardEvent(keysDownState);
-    }, [keysDownState, sendKeyboardEvent]);
 
   // executeMacro is used to execute a macro consisting of multiple steps.
   // Each step can have multiple keys, multiple modifiers and a delay.
@@ -111,12 +104,61 @@ export default function useKeyboard() {
     }
   };
 
+  const KEEPALIVE_INTERVAL = 75; // 200ms interval
+
+  const cancelKeepAlive = useCallback(() => {
+    if (keepAliveTimerRef.current) {
+      clearInterval(keepAliveTimerRef.current);
+      keepAliveTimerRef.current = null;
+    }
+  }, []);
+
+  const scheduleKeepAlive = useCallback(() => {
+    // Clear existing timer if it exists
+    if (keepAliveTimerRef.current) {
+      clearInterval(keepAliveTimerRef.current);
+    }
+
+    // Create new interval timer
+    keepAliveTimerRef.current = setInterval(() => {
+      sendKeypressKeepAliveHidRpc();
+    }, KEEPALIVE_INTERVAL);
+  }, [sendKeypressKeepAliveHidRpc]);
+
+  // resetKeyboardState is used to reset the keyboard state to no keys pressed and no modifiers.
+  // This is useful for macros and when the browser loses focus to ensure that the keyboard state
+  // is clean.
+  const resetKeyboardState = useCallback(async () => {
+    // Cancel keepalive since we're resetting the keyboard state
+    cancelKeepAlive();
+
+    // Reset the keys buffer to zeros and the modifier state to zero
+    keysDownState.keys.length = hidKeyBufferSize;
+    keysDownState.keys.fill(0);
+    keysDownState.modifier = 0;
+    sendKeyboardEvent(keysDownState);
+  }, [keysDownState, sendKeyboardEvent, cancelKeepAlive]);
+
   // handleKeyPress is used to handle a key press or release event.
   // This function handle both key press and key release events.
   // It checks if the keyPressReport API is available and sends the key press event.
   // If the keyPressReport API is not available, it simulates the device-side key
   // handling for legacy devices and updates the keysDownState accordingly.
   // It then sends the full keyboard state to the device.
+
+  const sendKeypress = useCallback(
+    (key: number, press: boolean) => {
+      cancelKeepAlive();
+
+      sendKeypressEventHidRpc(key, press);
+
+      if (press) {
+        scheduleKeepAlive();
+      }
+    },
+    [sendKeypressEventHidRpc, scheduleKeepAlive, cancelKeepAlive],
+  );
+
   const handleKeyPress = useCallback(
     async (key: number, press: boolean) => {
       if (rpcDataChannel?.readyState !== "open" && !rpcHidReady) return;
@@ -129,7 +171,7 @@ export default function useKeyboard() {
         // Older device version doesn't support this API, so we will switch to local key handling
         // In that case we will switch to local key handling and update the keysDownState
         // in client/browser-side code using simulateDeviceSideKeyHandlingForLegacyDevices.
-        sendKeypressEventHidRpc(key, press);
+        sendKeypress(key, press);
       } else {
         // if the keyPress api is not available, we need to handle the key locally
         const downState = simulateDeviceSideKeyHandlingForLegacyDevices(keysDownState, key, press);
@@ -147,7 +189,7 @@ export default function useKeyboard() {
       resetKeyboardState,
       rpcDataChannel?.readyState,
       sendKeyboardEvent,
-      sendKeypressEventHidRpc,
+      sendKeypress,
     ],
   );
 
@@ -210,5 +252,10 @@ export default function useKeyboard() {
     return { modifier: modifiers, keys };
   }
 
-  return { handleKeyPress, resetKeyboardState, executeMacro };
+  // Cleanup function to cancel keepalive timer
+  const cleanup = useCallback(() => {
+    cancelKeepAlive();
+  }, [cancelKeepAlive]);
+
+  return { handleKeyPress, resetKeyboardState, executeMacro, cleanup };
 }

ui/src/routes/devices.$id.tsx

@@ -136,6 +136,8 @@ export default function KvmIdRoute() {
     rpcDataChannel,
     setTransceiver,
     setRpcHidChannel,
+    setRpcHidUnreliableNonOrderedChannel,
+    setRpcHidUnreliableChannel,
   } = useRTCStore();
 
   const location = useLocation();
@@ -488,6 +490,24 @@ export default function KvmIdRoute() {
       setRpcHidChannel(rpcHidChannel);
     };
 
+    const rpcHidUnreliableChannel = pc.createDataChannel("hidrpc-unreliable-ordered", {
+      ordered: true,
+      maxRetransmits: 0,
+    });
+    rpcHidUnreliableChannel.binaryType = "arraybuffer";
+    rpcHidUnreliableChannel.onopen = () => {
+      setRpcHidUnreliableChannel(rpcHidUnreliableChannel);
+    };
+
+    const rpcHidUnreliableNonOrderedChannel = pc.createDataChannel("hidrpc-unreliable-nonordered", {
+      ordered: false,
+      maxRetransmits: 0,
+    });
+    rpcHidUnreliableNonOrderedChannel.binaryType = "arraybuffer";
+    rpcHidUnreliableNonOrderedChannel.onopen = () => {
+      setRpcHidUnreliableNonOrderedChannel(rpcHidUnreliableNonOrderedChannel);
+    };
+
     setPeerConnection(pc);
   }, [
     cleanupAndStopReconnecting,
@@ -499,6 +519,8 @@ export default function KvmIdRoute() {
     setPeerConnectionState,
     setRpcDataChannel,
     setRpcHidChannel,
+    setRpcHidUnreliableNonOrderedChannel,
+    setRpcHidUnreliableChannel,
     setTransceiver,
   ]);
 

webrtc.go

@@ -29,7 +29,12 @@ type Session struct {
 
 	hidRPCAvailable bool
 	hidQueueLock    sync.Mutex
-	hidQueue        []chan webrtc.DataChannelMessage
+	hidQueue        []chan hidQueueMessage
+}
+
+type hidQueueMessage struct {
+	webrtc.DataChannelMessage
+	channel string
 }
 
 type SessionConfig struct {
@@ -78,16 +83,59 @@ func (s *Session) initQueues() {
 	s.hidQueueLock.Lock()
 	defer s.hidQueueLock.Unlock()
 
-	s.hidQueue = make([]chan webrtc.DataChannelMessage, 0)
+	s.hidQueue = make([]chan hidQueueMessage, 0)
 	for i := 0; i < 4; i++ {
-		q := make(chan webrtc.DataChannelMessage, 256)
+		q := make(chan hidQueueMessage, 256)
 		s.hidQueue = append(s.hidQueue, q)
 	}
 }
 
 func (s *Session) handleQueues(index int) {
 	for msg := range s.hidQueue[index] {
-		onHidMessage(msg.Data, s)
+		onHidMessage(msg, s)
+	}
+}
+
+func getOnHidMessageHandler(session *Session, scopedLogger *zerolog.Logger, channel string) func(msg webrtc.DataChannelMessage) {
+	return func(msg webrtc.DataChannelMessage) {
+		l := scopedLogger.With().
+			Str("channel", channel).
+			Int("length", len(msg.Data)).
+			Logger()
+		// only log data if the log level is debug or lower
+		if scopedLogger.GetLevel() > zerolog.DebugLevel {
+			l = l.With().Str("data", string(msg.Data)).Logger()
+		}
+
+		if msg.IsString {
+			l.Warn().Msg("received string data in HID RPC message handler")
+			return
+		}
+
+		if len(msg.Data) < 1 {
+			l.Warn().Msg("received empty data in HID RPC message handler")
+			return
+		}
+
+		l.Trace().Msg("received data in HID RPC message handler")
+
+		// Enqueue to ensure ordered processing
+		queueIndex := hidrpc.GetQueueIndex(hidrpc.MessageType(msg.Data[0]))
+		if queueIndex >= len(session.hidQueue) || queueIndex < 0 {
+			l.Warn().Int("queueIndex", queueIndex).Msg("received data in HID RPC message handler, but queue index not found")
+			queueIndex = 3
+		}
+
+		queue := session.hidQueue[queueIndex]
+		if queue != nil {
+			queue <- hidQueueMessage{
+				DataChannelMessage: msg,
+				channel:            channel,
+			}
+		} else {
+			l.Warn().Int("queueIndex", queueIndex).Msg("received data in HID RPC message handler, but queue is nil")
+			return
+		}
 	}
 }
 
@@ -157,40 +205,12 @@ func newSession(config SessionConfig) (*Session, error) {
 		switch d.Label() {
 		case "hidrpc":
 			session.HidChannel = d
-			d.OnMessage(func(msg webrtc.DataChannelMessage) {
+			d.OnMessage(getOnHidMessageHandler(session, scopedLogger, "hidrpc"))
-				l := scopedLogger.With().Int("length", len(msg.Data)).Logger()
+		// we won't send anything over the unreliable channels
-				// only log data if the log level is debug or lower
+		case "hidrpc-unreliable-ordered":
-				if scopedLogger.GetLevel() > zerolog.DebugLevel {
+			d.OnMessage(getOnHidMessageHandler(session, scopedLogger, "hidrpc-unreliable-ordered"))
-					l = l.With().Str("data", string(msg.Data)).Logger()
+		case "hidrpc-unreliable-nonordered":
-				}
+			d.OnMessage(getOnHidMessageHandler(session, scopedLogger, "hidrpc-unreliable-nonordered"))
-
-				if msg.IsString {
-					l.Warn().Msg("received string data in HID RPC message handler")
-					return
-				}
-
-				if len(msg.Data) < 1 {
-					l.Warn().Msg("received empty data in HID RPC message handler")
-					return
-				}
-
-				l.Trace().Msg("received data in HID RPC message handler")
-
-				// Enqueue to ensure ordered processing
-				queueIndex := hidrpc.GetQueueIndex(hidrpc.MessageType(msg.Data[0]))
-				if queueIndex >= len(session.hidQueue) || queueIndex < 0 {
-					l.Warn().Int("queueIndex", queueIndex).Msg("received data in HID RPC message handler, but queue index not found")
-					queueIndex = 3
-				}
-
-				queue := session.hidQueue[queueIndex]
-				if queue != nil {
-					queue <- msg
-				} else {
-					l.Warn().Int("queueIndex", queueIndex).Msg("received data in HID RPC message handler, but queue is nil")
-					return
-				}
-			})
 		case "rpc":
 			session.RPCChannel = d
 			d.OnMessage(func(msg webrtc.DataChannelMessage) {