feat(ssh): add None auth method for passwordless tunnels

CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- SSH tunnels can authenticate with no password or key, for hosts that handle SSH auth themselves like Tailscale SSH. Pick **None** as the SSH auth method. (#1907)
+
 ## [0.58.0] - 2026-07-18
 
 ### Added

TablePro/Core/SSH/Auth/NoneAuthenticator.swift

@@ -0,0 +1,32 @@
+//
+//  NoneAuthenticator.swift
+//  TablePro
+//
+
+import Foundation
+import os
+
+import CLibSSH2
+
+internal struct NoneAuthenticator: SSHAuthenticator {
+    private static let logger = Logger(subsystem: "com.TablePro", category: "NoneAuthenticator")
+
+    func authenticate(session: OpaquePointer, username: String) throws {
+        let authList = libssh2_userauth_list(session, username, UInt32(username.utf8.count))
+        guard authList == nil else {
+            Self.logger.error("Passwordless auth rejected; server requires credentials")
+            throw SSHTunnelError.authenticationFailed(reason: .passwordlessRejected)
+        }
+
+        guard libssh2_userauth_authenticated(session) != 0 else {
+            var msgPtr: UnsafeMutablePointer<CChar>?
+            var msgLen: Int32 = 0
+            libssh2_session_last_error(session, &msgPtr, &msgLen, 0)
+            let detail = msgPtr.map { String(cString: $0) } ?? "Unknown error"
+            Self.logger.error("Passwordless auth failed: \(detail)")
+            throw SSHTunnelError.authenticationFailed(reason: .passwordlessRejected)
+        }
+
+        Self.logger.info("Passwordless authentication succeeded")
+    }
+}

TablePro/Core/SSH/LibSSH2TunnelFactory.swift

@@ -535,6 +535,9 @@ internal enum LibSSH2TunnelFactory {
                 password: credentials.sshPassword,
                 totpProvider: totpProvider
             )
+
+        case .none:
+            return NoneAuthenticator()
         }
     }
 

TablePro/Core/SSH/SSHTunnelManager.swift

@@ -16,6 +16,7 @@ enum AuthFailureReason: Sendable, Equatable {
     case verificationCode
     case privateKey
     case agentRejected
+    case passwordlessRejected
     case generic
 }
 
@@ -48,6 +49,8 @@ enum SSHTunnelError: Error, LocalizedError, Equatable {
                 return String(localized: "SSH private key rejected. Check the key file or passphrase.")
             case .agentRejected:
                 return String(localized: "SSH agent did not authenticate. Run ssh-add -l to check loaded keys.")
+            case .passwordlessRejected:
+                return String(localized: "The SSH server did not accept passwordless authentication. Choose Password, Private Key, or SSH Agent.")
             case .generic:
                 return String(localized: "SSH authentication failed. Check your credentials or private key.")
             }

TablePro/Core/Utilities/Connection/ConnectionURLFormatter.swift

@@ -195,6 +195,10 @@ struct ConnectionURLFormatter {
             }
         }
 
+        if ssh.enabled && ssh.authMethod == .none {
+            params.append("sshNoAuth=true")
+        }
+
         if let sslParam = sslModeParam(connection.sslConfig.mode) {
             params.append("sslmode=\(sslParam)")
         }

TablePro/Core/Utilities/Connection/ConnectionURLParser.swift

@@ -21,6 +21,7 @@ struct ParsedConnectionURL {
     let sshPassword: String?
     let usePrivateKey: Bool?
     let useSSHAgent: Bool?
+    let sshNoAuth: Bool?
     let agentSocket: String?
     let connectionName: String?
     let redisDatabase: Int?
@@ -123,6 +124,7 @@ struct ConnectionURLParser {
                 sshPassword: nil,
                 usePrivateKey: nil,
                 useSSHAgent: nil,
+                sshNoAuth: nil,
                 agentSocket: nil,
                 connectionName: nil,
                 redisDatabase: nil,
@@ -228,6 +230,7 @@ struct ConnectionURLParser {
             sshPassword: nil,
             usePrivateKey: nil,
             useSSHAgent: nil,
+            sshNoAuth: nil,
             agentSocket: nil,
             connectionName: ext.connectionName,
             redisDatabase: redisDatabase,
@@ -408,6 +411,7 @@ struct ConnectionURLParser {
             sshPassword: sshPassword,
             usePrivateKey: ext.usePrivateKey,
             useSSHAgent: ext.useSSHAgent,
+            sshNoAuth: ext.sshNoAuth,
             agentSocket: ext.agentSocket,
             connectionName: ext.connectionName,
             redisDatabase: nil,
@@ -506,6 +510,7 @@ struct ConnectionURLParser {
             sshPassword: nil,
             usePrivateKey: nil,
             useSSHAgent: nil,
+            sshNoAuth: nil,
             agentSocket: nil,
             connectionName: ext.connectionName,
             redisDatabase: nil,
@@ -534,6 +539,7 @@ struct ConnectionURLParser {
         var connectionName: String?
         var usePrivateKey: Bool?
         var useSSHAgent: Bool?
+        var sshNoAuth: Bool?
         var agentSocket: String?
         var statusColor: String?
         var envTag: String?
@@ -577,6 +583,10 @@ struct ConnectionURLParser {
                 ext.useSSHAgent = value.lowercased() == "true"
                 continue
             }
+            if keyStr == "sshnoauth" {
+                ext.sshNoAuth = value.lowercased() == "true"
+                continue
+            }
             if keyStr == "agentsocket" {
                 ext.agentSocket = value.removingPercentEncoding ?? value
                 continue

TablePro/Core/Utilities/Connection/TransientConnectionFactory.swift

@@ -22,6 +22,9 @@ internal enum TransientConnectionFactory {
                 sshConfig.authMethod = .sshAgent
                 sshConfig.agentSocketPath = parsed.agentSocket ?? ""
             }
+            if parsed.sshNoAuth == true {
+                sshConfig.authMethod = .none
+            }
         }
 
         var sslConfig = SSLConfiguration()

TablePro/Models/Connection/SSHTypes.swift

@@ -10,6 +10,7 @@ enum SSHAuthMethod: String, CaseIterable, Identifiable, Codable {
     case privateKey = "Private Key"
     case sshAgent = "SSH Agent"
     case keyboardInteractive = "Keyboard Interactive"
+    case none = "None"
 
     var id: String { rawValue }
 
@@ -19,6 +20,7 @@ enum SSHAuthMethod: String, CaseIterable, Identifiable, Codable {
         case .privateKey: return String(localized: "Private Key")
         case .sshAgent: return String(localized: "SSH Agent")
         case .keyboardInteractive: return String(localized: "Keyboard Interactive")
+        case .none: return String(localized: "None")
         }
     }
 
@@ -28,6 +30,7 @@ enum SSHAuthMethod: String, CaseIterable, Identifiable, Codable {
         case .privateKey: return "doc.text.fill"
         case .sshAgent: return "person.badge.key.fill"
         case .keyboardInteractive: return "keyboard"
+        case .none: return "key.slash"
         }
     }
 }
@@ -140,7 +143,7 @@ extension SSHConfiguration {
         host = try container.decode(String.self, forKey: .host)
         port = try container.decodeIfPresent(Int.self, forKey: .port)
         username = try container.decode(String.self, forKey: .username)
-        authMethod = try container.decode(SSHAuthMethod.self, forKey: .authMethod)
+        authMethod = (try? container.decodeIfPresent(SSHAuthMethod.self, forKey: .authMethod)) ?? .password
         privateKeyPath = try container.decode(String.self, forKey: .privateKeyPath)
         agentSocketPath = try container.decode(String.self, forKey: .agentSocketPath)
         jumpHosts = try container.decodeIfPresent([SSHJumpHost].self, forKey: .jumpHosts) ?? []

TablePro/Views/Connection/ConnectionSSHTunnelView.swift

@@ -202,6 +202,10 @@ struct ConnectionSSHTunnelView: View {
                     Text(String(localized: "Password is sent via keyboard-interactive challenge-response."))
                         .font(.caption)
                         .foregroundStyle(.secondary)
+                } else if sshState.authMethod == .none {
+                    Text("No credentials are sent. Use this when the server handles authentication itself, such as a Tailscale SSH host.")
+                        .font(.caption)
+                        .foregroundStyle(.secondary)
                 } else {
                     LabeledContent(String(localized: "Key File")) {
                         HStack {

TablePro/Views/Connection/SSHProfileEditorView.swift

@@ -56,7 +56,7 @@ struct SSHProfileEditorView: View {
         let hostValid = !host.trimmingCharacters(in: .whitespaces).isEmpty
         let portValid = port.isEmpty || (Int(port).map { (1...65_535).contains($0) } ?? false)
         let authValid = authMethod == .password || authMethod == .sshAgent
-            || authMethod == .keyboardInteractive || !privateKeyPath.isEmpty
+            || authMethod == .keyboardInteractive || authMethod == .none || !privateKeyPath.isEmpty
         let jumpValid = jumpHosts.allSatisfy(\.isValid)
         return nameValid && hostValid && portValid && authValid && jumpValid
     }
@@ -167,6 +167,10 @@ struct SSHProfileEditorView: View {
                 Text(String(localized: "Password is sent via keyboard-interactive challenge-response."))
                     .font(.caption)
                     .foregroundStyle(.secondary)
+            } else if authMethod == .none {
+                Text("No credentials are sent. Use this when the server handles authentication itself, such as a Tailscale SSH host.")
+                    .font(.caption)
+                    .foregroundStyle(.secondary)
             } else {
                 LabeledContent(String(localized: "Key File")) {
                     HStack {

TablePro/Views/ConnectionForm/ConnectionFormCoordinator.swift

@@ -786,6 +786,9 @@ final class ConnectionFormCoordinator {
                 ssh.state.authMethod = .sshAgent
                 ssh.state.applyAgentSocketPath(parsed.agentSocket ?? "")
             }
+            if parsed.sshNoAuth == true {
+                ssh.state.authMethod = .none
+            }
         }
 
         if let multiHost = parsed.multiHost, !multiHost.isEmpty {

TableProTests/Core/SSH/Auth/AuthFailureReasonTests.swift

@@ -51,6 +51,15 @@ struct AuthFailureReasonTests {
         #expect(description.localizedCaseInsensitiveContains("agent"))
     }
 
+    @Test("Passwordless reason points at the server, not the user's credentials")
+    func passwordlessRejectedMessage() {
+        let error = SSHTunnelError.authenticationFailed(reason: .passwordlessRejected)
+        let description = error.errorDescription ?? ""
+
+        #expect(description.localizedCaseInsensitiveContains("passwordless"))
+        #expect(!description.localizedCaseInsensitiveContains("verification code"))
+    }
+
     @Test("Generic reason keeps the original wording for unknown cases")
     func genericMessage() {
         let error = SSHTunnelError.authenticationFailed(reason: .generic)
@@ -64,6 +73,7 @@ struct AuthFailureReasonTests {
             SSHTunnelError.authenticationFailed(reason: .verificationCode).errorDescription ?? "",
             SSHTunnelError.authenticationFailed(reason: .privateKey).errorDescription ?? "",
             SSHTunnelError.authenticationFailed(reason: .agentRejected).errorDescription ?? "",
+            SSHTunnelError.authenticationFailed(reason: .passwordlessRejected).errorDescription ?? "",
             SSHTunnelError.authenticationFailed(reason: .generic).errorDescription ?? ""
         ]
 

TableProTests/Core/SSH/Auth/BuildAuthenticatorTests.swift

@@ -118,6 +118,56 @@ struct BuildAuthenticatorTests {
         #expect(kbdint.totpProvider == nil)
     }
 
+    @Test("None auth method returns a NoneAuthenticator")
+    func noneReturnsNoneAuthenticator() throws {
+        var config = SSHConfiguration(
+            enabled: true,
+            host: "ssh.example.com",
+            username: "alice",
+            authMethod: .none
+        )
+        config.totpMode = .none
+        let credentials = SSHTunnelCredentials(
+            sshPassword: nil,
+            keyPassphrase: nil,
+            totpSecret: nil,
+            totpProvider: nil
+        )
+
+        let authenticator = try LibSSH2TunnelFactory.buildAuthenticator(
+            config: config,
+            resolved: resolved(),
+            credentials: credentials
+        )
+
+        #expect(authenticator is NoneAuthenticator)
+    }
+
+    @Test("Password auth method with no password throws before any libssh2 call")
+    func passwordWithoutCredentialThrows() {
+        var config = SSHConfiguration(
+            enabled: true,
+            host: "ssh.example.com",
+            username: "alice",
+            authMethod: .password
+        )
+        config.totpMode = .none
+        let credentials = SSHTunnelCredentials(
+            sshPassword: nil,
+            keyPassphrase: nil,
+            totpSecret: nil,
+            totpProvider: nil
+        )
+
+        #expect(throws: SSHTunnelError.authenticationFailed(reason: .password)) {
+            try LibSSH2TunnelFactory.buildAuthenticator(
+                config: config,
+                resolved: resolved(),
+                credentials: credentials
+            )
+        }
+    }
+
     @Test("Keyboard-Interactive auth method passes the password through directly")
     func keyboardInteractivePassesPassword() throws {
         var config = SSHConfiguration(

TableProTests/Core/SSH/SSHConfigurationTests.swift

@@ -200,6 +200,42 @@ struct SSHConfigurationTests {
         #expect(config.enabled == true)
     }
 
+    @Test("None auth method is valid and round-trips through Codable")
+    func testNoneAuthRoundTrips() throws {
+        let config = SSHConfiguration(
+            enabled: true, host: "tailscale.example.com", username: "admin",
+            authMethod: .none
+        )
+        #expect(config.isValid == true)
+
+        let data = try JSONEncoder().encode(config)
+        let decoded = try JSONDecoder().decode(SSHConfiguration.self, from: data)
+        #expect(decoded.authMethod == .none)
+        #expect(decoded.host == "tailscale.example.com")
+    }
+
+    @Test("Unknown authMethod falls back to Password and preserves the tunnel config")
+    func testUnknownAuthMethodFallsBackToPassword() throws {
+        let jsonString = """
+        {
+            "enabled": true,
+            "host": "example.com",
+            "port": 2222,
+            "username": "admin",
+            "authMethod": "FutureMethodFromNewerApp",
+            "privateKeyPath": "",
+            "agentSocketPath": ""
+        }
+        """
+        let json = Data(jsonString.utf8)
+
+        let config = try JSONDecoder().decode(SSHConfiguration.self, from: json)
+        #expect(config.authMethod == .password)
+        #expect(config.host == "example.com")
+        #expect(config.port == 2_222)
+        #expect(config.enabled == true)
+    }
+
     @Test("Decoding ignores legacy useSSHConfig field")
     func testLegacyUseSSHConfigIgnored() throws {
         let jsonString = """

TableProTests/Core/Utilities/ConnectionURLFormatterTests.swift

@@ -223,6 +223,23 @@ struct ConnectionURLFormatterTests {
         #expect(url.contains("usePrivateKey=true"))
     }
 
+    @Test("SSH with no auth adds query param")
+    func testSSHNoAuth() {
+        var sshConfig = SSHConfiguration()
+        sshConfig.enabled = true
+        sshConfig.host = "sshhost"
+        sshConfig.port = 22
+        sshConfig.username = "root"
+        sshConfig.authMethod = .none
+
+        let conn = DatabaseConnection(
+            name: "", host: "localhost", port: 3_306, database: "db",
+            username: "user", type: .mysql, sshConfig: sshConfig
+        )
+        let url = ConnectionURLFormatter.format(conn, password: "pass", sshPassword: nil)
+        #expect(url.contains("sshNoAuth=true"))
+    }
+
     // MARK: - SSL Mode
 
     @Test("SSL mode included in query string")

TableProTests/Core/Utilities/ConnectionURLParserTests.swift

@@ -445,6 +445,15 @@ struct ConnectionURLParserTests {
         #expect(parsed.usePrivateKey == true)
     }
 
+    @Test("SSH URL with sshNoAuth")
+    func testSSHURLWithNoAuth() {
+        let result = ConnectionURLParser.parse("mysql+ssh://root@host:22/user:pass@localhost/db?sshNoAuth=true")
+        guard case .success(let parsed) = result else {
+            Issue.record("Expected success"); return
+        }
+        #expect(parsed.sshNoAuth == true)
+    }
+
     @Test("SSH URL with SSH password")
     func testSSHURLWithSSHPassword() {
         let result = ConnectionURLParser.parse("mysql+ssh://root:sshpass@jumphost:22/dbuser:dbpass@localhost/db")

docs/databases/ssh-tunneling.mdx

@@ -57,6 +57,9 @@ To reuse one SSH config across several connections, save it as a profile with **
   <Tab title="Keyboard Interactive">
     Sends your password through SSH's keyboard-interactive challenge-response. Use this when the server rejects plain password auth, which is common with PAM-based setups.
   </Tab>
+  <Tab title="None">
+    Sends no password or key. Use this when the server authenticates the connection itself, such as a [Tailscale SSH](https://tailscale.com/kb/1193/tailscale-ssh) host or a bastion configured for passwordless access. If the server still requires credentials, the connection fails with a message telling you to pick another method.
+  </Tab>
 </Tabs>
 
 ### Two-Factor Authentication (TOTP)