Use keychain service as item context

Primary key = (context, username)

CHANGELOG.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Changed
 
 - Update API to access current Wi-Fi SSID.
+- Refactor access to keychain.
 
 ## 3.0.0 (2020-11-15)
 

TunnelKit/Sources/AppExtension/Keychain.swift

@@ -54,39 +54,18 @@ public enum KeychainError: Error {
 
 /// Wrapper for easy keychain access and modification.
 public class Keychain {
-    private let service: String?
-
     private let accessGroup: String?
 
-    /// :nodoc:
-    public init() {
-        service = Bundle.main.bundleIdentifier
-        accessGroup = nil
-    }
-
     /**
-     Creates a keychain in an App Group.
+     Creates a keychain.
 
-     - Parameter group: The App Group.
+     - Parameter group: An optional App Group.
-     - Precondition: Proper App Group entitlements.
+     - Precondition: Proper App Group entitlements (if group is non-nil).
      **/
-    public init(group: String) {
+    public init(group: String?) {
-        service = nil
         accessGroup = group
     }
     
-    /**
-     Creates a keychain in an App Group and a Team ID prefix.
-     
-     - Parameter team: The Team ID prefix.
-     - Parameter group: The App Group.
-     - Precondition: Proper App Group entitlements.
-     **/
-    public init(team: String, group: String) {
-        service = nil
-        accessGroup = "\(team).\(group)"
-    }
-    
     // MARK: Password
     
     /**
@@ -94,16 +73,16 @@ public class Keychain {
 
      - Parameter password: The password to set.
      - Parameter username: The username to set the password for.
-     - Parameter label: An optional label.
+     - Parameter context: An optional context.
      - Throws: `KeychainError.add` if unable to add the password to the keychain.
      **/
-    public func set(password: String, for username: String, label: String? = nil) throws {
+    public func set(password: String, for username: String, context: String? = nil) throws {
         do {
-            let currentPassword = try self.password(for: username)
+            let currentPassword = try self.password(for: username, context: context)
             guard password != currentPassword else {
                 return
             }
-            removePassword(for: username)
+            removePassword(for: username, context: context)
         } catch let e as KeychainError {
 
             // rethrow cancelation
@@ -115,17 +94,14 @@ public class Keychain {
         }
 
         var query = [String: Any]()
-        setScope(query: &query)
+        setScope(query: &query, context: context)
         query[kSecClass as String] = kSecClassGenericPassword
-        if let label = label {
-            query[kSecAttrLabel as String] = label
-        }
         query[kSecAttrAccount as String] = username
         query[kSecAttrAccessible as String] = kSecAttrAccessibleAfterFirstUnlock
         query[kSecValueData as String] = password.data(using: .utf8)
 
         let status = SecItemAdd(query as CFDictionary, nil)
-        guard (status == errSecSuccess) else {
+        guard status == errSecSuccess else {
             throw KeychainError.add
         }
     }
@@ -134,28 +110,30 @@ public class Keychain {
      Removes a password.
 
      - Parameter username: The username to remove the password for.
+     - Parameter context: An optional context.
      - Returns: `true` if the password was successfully removed.
      **/
-    @discardableResult public func removePassword(for username: String) -> Bool {
+    @discardableResult public func removePassword(for username: String, context: String? = nil) -> Bool {
         var query = [String: Any]()
-        setScope(query: &query)
+        setScope(query: &query, context: context)
         query[kSecClass as String] = kSecClassGenericPassword
         query[kSecAttrAccount as String] = username
 
         let status = SecItemDelete(query as CFDictionary)
-        return (status == errSecSuccess)
+        return status == errSecSuccess
     }
 
     /**
      Gets a password.
 
      - Parameter username: The username to get the password for.
+     - Parameter context: An optional context.
      - Returns: The password for the input username.
      - Throws: `KeychainError.notFound` if unable to find the password in the keychain.
      **/
-    public func password(for username: String) throws -> String {
+    public func password(for username: String, context: String? = nil) throws -> String {
         var query = [String: Any]()
-        setScope(query: &query)
+        setScope(query: &query, context: context)
         query[kSecClass as String] = kSecClassGenericPassword
         query[kSecAttrAccount as String] = username
         query[kSecMatchLimit as String] = kSecMatchLimitOne
@@ -185,12 +163,13 @@ public class Keychain {
      Gets a password reference.
 
      - Parameter username: The username to get the password for.
+     - Parameter context: An optional context.
      - Returns: The password reference for the input username.
      - Throws: `KeychainError.notFound` if unable to find the password in the keychain.
      **/
-    public func passwordReference(for username: String) throws -> Data {
+    public func passwordReference(for username: String, context: String? = nil) throws -> Data {
         var query = [String: Any]()
-        setScope(query: &query)
+        setScope(query: &query, context: context)
         query[kSecClass as String] = kSecClassGenericPassword
         query[kSecAttrAccount as String] = username
         query[kSecMatchLimit as String] = kSecMatchLimitOne
@@ -218,12 +197,16 @@ public class Keychain {
 
      - Parameter username: The username to get the password for.
      - Parameter reference: The password reference.
+     - Parameter context: An optional context.
      - Returns: The password for the input username and reference.
      - Throws: `KeychainError.notFound` if unable to find the password in the keychain.
      **/
-    public static func password(for username: String, reference: Data) throws -> String {
+    public static func password(for username: String, reference: Data, context: String? = nil) throws -> String {
         var query = [String: Any]()
         query[kSecClass as String] = kSecClassGenericPassword
+        if let context = context {
+            query[kSecAttrService as String] = context
+        }
         query[kSecAttrAccount as String] = username
         query[kSecMatchItemList as String] = [reference]
         query[kSecReturnData as String] = true
@@ -331,18 +314,17 @@ public class Keychain {
         query.removeValue(forKey: kSecAttrService as String)
 
         let status = SecItemDelete(query as CFDictionary)
-        return (status == errSecSuccess)
+        return status == errSecSuccess
     }
     
     // MARK: Helpers
     
-    private func setScope(query: inout [String: Any]) {
+    private func setScope(query: inout [String: Any], context: String?) {
-        if let service = service {
+        if let accessGroup = accessGroup {
-            query[kSecAttrService as String] = service
-        } else if let accessGroup = accessGroup {
             query[kSecAttrAccessGroup as String] = accessGroup
-        } else {
+        }
-            fatalError("No service nor accessGroup set")
+        if let context = context {
+            query[kSecAttrService as String] = context
         }
     }
 }

TunnelKit/Sources/Protocols/OpenVPN/AppExtension/OpenVPNTunnelProvider+Configuration.swift

@@ -403,12 +403,12 @@ extension OpenVPNTunnelProvider {
             if let username = credentials?.username, let password = credentials?.password {
                 let keychain = Keychain(group: appGroup)
                 do {
-                    try keychain.set(password: password, for: username, label: Bundle.main.bundleIdentifier)
+                    try keychain.set(password: password, for: username, context: bundleIdentifier)
                 } catch _ {
                     throw ProviderConfigurationError.credentials(details: "keychain.set()")
                 }
                 protocolConfiguration.username = username
-                protocolConfiguration.passwordReference = try? keychain.passwordReference(for: username)
+                protocolConfiguration.passwordReference = try? keychain.passwordReference(for: username, context: bundleIdentifier)
             }
             protocolConfiguration.providerConfiguration = generatedProviderConfiguration(appGroup: appGroup)