Statically load whether or not a key requires authentication before use (#357)

* Add protocol requirements

* Load auth settings.

* Updates.

* Update preview store

* Add lock icon

Sources/Packages/Sources/SecretAgentKit/Agent.swift

@@ -113,7 +113,7 @@ extension Agent {
 
         let dataToSign = reader.readNextChunk()
         let signed = try store.sign(data: dataToSign, with: secret, for: provenance)
-        let derSignature = signed.data
+        let derSignature = signed
 
         let curveData = writer.curveType(for: secret.algorithm, length: secret.keySize).data(using: .utf8)!
 
@@ -154,7 +154,7 @@ extension Agent {
         signedData.append(writer.lengthAndData(of: sub))
 
         if let witness = witness {
-            try witness.witness(accessTo: secret, from: store, by: provenance, requiredAuthentication: signed.requiredAuthentication)
+            try witness.witness(accessTo: secret, from: store, by: provenance)
         }
 
         Logger().debug("Agent signed request")

Sources/Packages/Sources/SecretAgentKit/SigningWitness.swift

@@ -17,7 +17,6 @@ public protocol SigningWitness {
     ///   - secret: The `Secret` that will was used to sign the request.
     ///   - store: The `Store` that signed the request..
     ///   - provenance: A `SigningRequestProvenance` object describing the origin of the request.
-    ///   - requiredAuthentication: A boolean describing whether or not authentication was required for the request.
-    func witness(accessTo secret: AnySecret, from store: AnySecretStore, by provenance: SigningRequestProvenance, requiredAuthentication: Bool) throws
+    func witness(accessTo secret: AnySecret, from store: AnySecretStore, by provenance: SigningRequestProvenance) throws
 
 }

Sources/Packages/Sources/SecretKit/Documentation.docc/Documentation.md

@@ -27,5 +27,8 @@ SecretKit is a collection of protocols describing secrets and stores.
 
 ### Signing Process
 
-- ``SignedData``
 - ``SigningRequestProvenance``
+
+### Authentication Persistence
+
+- ``PersistedAuthenticationContext``

Sources/Packages/Sources/SecretKit/Erasers/AnySecret.swift

@@ -9,6 +9,7 @@ public struct AnySecret: Secret {
     private let _name: () -> String
     private let _algorithm: () -> Algorithm
     private let _keySize: () -> Int
+    private let _requiresAuthentication: () -> Bool
     private let _publicKey: () -> Data
 
     public init<T>(_ secret: T) where T: Secret {
@@ -19,6 +20,7 @@ public struct AnySecret: Secret {
             _name = secret._name
             _algorithm = secret._algorithm
             _keySize = secret._keySize
+            _requiresAuthentication = secret._requiresAuthentication
             _publicKey = secret._publicKey
         } else {
             base = secret as Any
@@ -27,6 +29,7 @@ public struct AnySecret: Secret {
             _name = { secret.name }
             _algorithm = { secret.algorithm }
             _keySize = { secret.keySize }
+            _requiresAuthentication = { secret.requiresAuthentication }
             _publicKey = { secret.publicKey }
         }
     }
@@ -47,6 +50,10 @@ public struct AnySecret: Secret {
         _keySize()
     }
 
+    public var requiresAuthentication: Bool {
+        _requiresAuthentication()
+    }
+
     public var publicKey: Data {
         _publicKey()
     }

Sources/Packages/Sources/SecretKit/Erasers/AnySecretStore.swift

@@ -9,7 +9,8 @@ public class AnySecretStore: SecretStore {
     private let _id: () -> UUID
     private let _name: () -> String
     private let _secrets: () -> [AnySecret]
-    private let _sign: (Data, AnySecret, SigningRequestProvenance) throws -> SignedData
+    private let _sign: (Data, AnySecret, SigningRequestProvenance) throws -> Data
+    private let _existingPersistedAuthenticationContext: (AnySecret) -> PersistedAuthenticationContext?
     private let _persistAuthentication: (AnySecret, TimeInterval) throws -> Void
 
     private var sink: AnyCancellable?
@@ -21,6 +22,7 @@ public class AnySecretStore: SecretStore {
         _id = { secretStore.id }
         _secrets = { secretStore.secrets.map { AnySecret($0) } }
         _sign = { try secretStore.sign(data: $0, with: $1.base as! SecretStoreType.SecretType, for: $2) }
+        _existingPersistedAuthenticationContext = { secretStore.existingPersistedAuthenticationContext(secret: $0.base as! SecretStoreType.SecretType) }
         _persistAuthentication = { try secretStore.persistAuthentication(secret: $0.base as! SecretStoreType.SecretType, forDuration: $1) }
         sink = secretStore.objectWillChange.sink { _ in
             self.objectWillChange.send()
@@ -43,10 +45,14 @@ public class AnySecretStore: SecretStore {
         return _secrets()
     }
 
-    public func sign(data: Data, with secret: AnySecret, for provenance: SigningRequestProvenance) throws -> SignedData {
+    public func sign(data: Data, with secret: AnySecret, for provenance: SigningRequestProvenance) throws -> Data {
         try _sign(data, secret, provenance)
     }
 
+    public func existingPersistedAuthenticationContext(secret: AnySecret) -> PersistedAuthenticationContext? {
+        _existingPersistedAuthenticationContext(secret)
+    }
+
     public func persistAuthentication(secret: AnySecret, forDuration duration: TimeInterval) throws {
         try _persistAuthentication(secret, duration)
     }

Sources/Packages/Sources/SecretKit/Types/PersistedAuthenticationContext.swift

@@ -0,0 +1,9 @@
+import Foundation
+
+/// Protocol describing a persisted authentication context. This is an authorization that can be reused for multiple access to a secret that requires authentication for a specific period of time.
+public protocol PersistedAuthenticationContext {
+    /// Whether the context remains valid.
+    var valid: Bool { get }
+    /// The date at which the authorization expires and the context becomes invalid.
+    var expiration: Date { get }
+}

Sources/Packages/Sources/SecretKit/Types/Secret.swift

@@ -9,6 +9,8 @@ public protocol Secret: Identifiable, Hashable {
     var algorithm: Algorithm { get }
     /// The key size for the secret.
     var keySize: Int { get }
+    /// Whether the secret requires authentication before use.
+    var requiresAuthentication: Bool { get }
     /// The public key data for the secret.
     var publicKey: Data { get }
 

Sources/Packages/Sources/SecretKit/Types/SecretStore.swift

@@ -20,8 +20,14 @@ public protocol SecretStore: ObservableObject, Identifiable {
     ///   - data: The data to sign.
     ///   - secret: The ``Secret`` to sign with.
     ///   - provenance: A ``SigningRequestProvenance`` describing where the request came from.
-    /// - Returns: A ``SignedData`` object, containing the signature and metadata about the signature process.
-    func sign(data: Data, with secret: SecretType, for provenance: SigningRequestProvenance) throws -> SignedData
+    /// - Returns: The signed data.
+    func sign(data: Data, with secret: SecretType, for provenance: SigningRequestProvenance) throws -> Data
+
+    /// Checks to see if there is currently a valid persisted authentication for a given secret.
+    /// - Parameters:
+    ///   - secret: The ``Secret`` to check if there is a persisted authentication for.
+    /// - Returns: A persisted authentication context, if a valid one exists.
+    func existingPersistedAuthenticationContext(secret: SecretType) -> PersistedAuthenticationContext?
 
     /// Persists user authorization for access to a secret.
     /// - Parameters:

Sources/Packages/Sources/SecretKit/Types/SignedData.swift

@@ -1,20 +0,0 @@
-import Foundation
-
-/// Describes the output of a sign request.
-public struct SignedData {
-
-    /// The signed data.
-    public let data: Data
-    /// A boolean describing whether authentication was required during the signature process.
-    public let requiredAuthentication: Bool
-
-    /// Initializes a new SignedData.
-    /// - Parameters:
-    ///   - data: The signed data.
-    ///   - requiredAuthentication: A boolean describing whether authentication was required during the signature process.
-    public init(data: Data, requiredAuthentication: Bool) {
-        self.data = data
-        self.requiredAuthentication = requiredAuthentication
-    }
-
-}

Sources/Packages/Sources/SecureEnclaveSecretKit/SecureEnclaveSecret.swift

@@ -11,6 +11,7 @@ extension SecureEnclave {
         public let name: String
         public let algorithm = Algorithm.ellipticCurve
         public let keySize = 256
+        public let requiresAuthentication: Bool
         public let publicKey: Data
 
     }

Sources/Packages/Sources/SecureEnclaveSecretKit/SecureEnclaveStore.swift

@@ -100,7 +100,7 @@ extension SecureEnclave {
             reloadSecrets()
         }
         
-        public func sign(data: Data, with secret: SecretType, for provenance: SigningRequestProvenance) throws -> SignedData {
+        public func sign(data: Data, with secret: SecretType, for provenance: SigningRequestProvenance) throws -> Data {
             let context: LAContext
             if let existing = persistedAuthenticationContexts[secret], existing.valid {
                 context = existing.context
@@ -131,16 +131,15 @@ extension SecureEnclave {
             let key = untypedSafe as! SecKey
             var signError: SecurityError?
 
-            let signingStartTime = Date()
             guard let signature = SecKeyCreateSignature(key, .ecdsaSignatureMessageX962SHA256, data as CFData, &signError) else {
                 throw SigningError(error: signError)
             }
-            let signatureDuration = Date().timeIntervalSince(signingStartTime)
-            // Hack to determine if the user had to authenticate to sign.
-            // Since there's now way to inspect SecAccessControl to determine (afaict).
-            let requiredAuthentication = signatureDuration > Constants.unauthenticatedThreshold
+            return signature as Data
+        }
 
-            return SignedData(data: signature as Data, requiredAuthentication: requiredAuthentication)
+        public func existingPersistedAuthenticationContext(secret: Secret) -> PersistedAuthenticationContext? {
+            guard let persisted = persistedAuthenticationContexts[secret], persisted.valid else { return nil }
+            return persisted
         }
 
         public func persistAuthentication(secret: Secret, forDuration duration: TimeInterval) throws {
@@ -183,7 +182,7 @@ extension SecureEnclave.Store {
 
     /// Loads all secrets from the store.
     private func loadSecrets() {
-        let attributes = [
+        let publicAttributes = [
             kSecClass: kSecClassKey,
             kSecAttrKeyType: SecureEnclave.Constants.keyType,
             kSecAttrApplicationTag: SecureEnclave.Constants.keyTag,
@@ -192,16 +191,46 @@ extension SecureEnclave.Store {
             kSecMatchLimit: kSecMatchLimitAll,
             kSecReturnAttributes: true
             ] as CFDictionary
-        var untyped: CFTypeRef?
-        SecItemCopyMatching(attributes, &untyped)
-        guard let typed = untyped as? [[CFString: Any]] else { return }
-        let wrapped: [SecureEnclave.Secret] = typed.map {
+        var publicUntyped: CFTypeRef?
+        SecItemCopyMatching(publicAttributes, &publicUntyped)
+        guard let publicTyped = publicUntyped as? [[CFString: Any]] else { return }
+        let privateAttributes = [
+            kSecClass: kSecClassKey,
+            kSecAttrKeyType: SecureEnclave.Constants.keyType,
+            kSecAttrApplicationTag: SecureEnclave.Constants.keyTag,
+            kSecAttrKeyClass: kSecAttrKeyClassPrivate,
+            kSecReturnRef: true,
+            kSecMatchLimit: kSecMatchLimitAll,
+            kSecReturnAttributes: true
+            ] as CFDictionary
+        var privateUntyped: CFTypeRef?
+        SecItemCopyMatching(privateAttributes, &privateUntyped)
+        guard let privateTyped = privateUntyped as? [[CFString: Any]] else { return }
+        let privateMapped = privateTyped.reduce(into: [:] as [Data: [CFString: Any]]) { partialResult, next in
+            let id = next[kSecAttrApplicationLabel] as! Data
+            partialResult[id] = next
+        }
+        let authNotRequiredAccessControl: SecAccessControl =
+            SecAccessControlCreateWithFlags(kCFAllocatorDefault,
+                                            kSecAttrAccessibleWhenUnlockedThisDeviceOnly,
+                                            [.privateKeyUsage],
+                                            nil)!
+
+        let wrapped: [SecureEnclave.Secret] = publicTyped.map {
             let name = $0[kSecAttrLabel] as? String ?? "Unnamed"
             let id = $0[kSecAttrApplicationLabel] as! Data
             let publicKeyRef = $0[kSecValueRef] as! SecKey
             let publicKeyAttributes = SecKeyCopyAttributes(publicKeyRef) as! [CFString: Any]
             let publicKey = publicKeyAttributes[kSecValueData] as! Data
-            return SecureEnclave.Secret(id: id, name: name, publicKey: publicKey)
+            let privateKey = privateMapped[id]
+            let requiresAuth: Bool
+            if let authRequirements = privateKey?[kSecAttrAccessControl] {
+                // Unfortunately we can't inspect the access control object directly, but it does behave predicatable with equality.
+                requiresAuth = authRequirements as! SecAccessControl != authNotRequiredAccessControl
+            } else {
+                requiresAuth = false
+            }
+            return SecureEnclave.Secret(id: id, name: name, requiresAuthentication: requiresAuth, publicKey: publicKey)
         }
         secrets.append(contentsOf: wrapped)
     }
@@ -264,7 +293,7 @@ extension SecureEnclave {
 extension SecureEnclave {
 
     /// A context describing a persisted authentication.
-    private struct PersistentAuthenticationContext {
+    private struct PersistentAuthenticationContext: PersistedAuthenticationContext {
 
         /// The Secret to persist authentication for.
         let secret: Secret
@@ -272,7 +301,7 @@ extension SecureEnclave {
         let context: LAContext
         /// An expiration date for the context.
         /// - Note -  Monotonic time instead of Date() to prevent people setting the clock back.
-        let expiration: UInt64
+        let monotonicExpiration: UInt64
 
         /// Initializes a context.
         /// - Parameters:
@@ -283,12 +312,18 @@ extension SecureEnclave {
             self.secret = secret
             self.context = context
             let durationInNanoSeconds = Measurement(value: duration, unit: UnitDuration.seconds).converted(to: .nanoseconds).value
-            self.expiration = clock_gettime_nsec_np(CLOCK_MONOTONIC) + UInt64(durationInNanoSeconds)
+            self.monotonicExpiration = clock_gettime_nsec_np(CLOCK_MONOTONIC) + UInt64(durationInNanoSeconds)
         }
 
         /// A boolean describing whether or not the context is still valid.
         var valid: Bool {
-            clock_gettime_nsec_np(CLOCK_MONOTONIC) < expiration
+            clock_gettime_nsec_np(CLOCK_MONOTONIC) < monotonicExpiration
+        }
+
+        var expiration: Date {
+            let remainingNanoseconds = monotonicExpiration - clock_gettime_nsec_np(CLOCK_MONOTONIC)
+            let remainingInSeconds = Measurement(value: Double(remainingNanoseconds), unit: UnitDuration.nanoseconds).converted(to: .seconds).value
+            return Date(timeIntervalSinceNow: remainingInSeconds)
         }
     }
 

Sources/Packages/Sources/SmartCardSecretKit/SmartCardSecret.swift

@@ -11,6 +11,7 @@ extension SmartCard {
         public let name: String
         public let algorithm: Algorithm
         public let keySize: Int
+        public let requiresAuthentication: Bool = false
         public let publicKey: Data
 
     }

Sources/Packages/Sources/SmartCardSecretKit/SmartCardStore.swift

@@ -44,7 +44,7 @@ extension SmartCard {
             fatalError("Keys must be deleted on the smart card.")
         }
 
-        public func sign(data: Data, with secret: SecretType, for provenance: SigningRequestProvenance) throws -> SignedData {
+        public func sign(data: Data, with secret: SecretType, for provenance: SigningRequestProvenance) throws -> Data {
             guard let tokenID = tokenID else { fatalError() }
             let context = LAContext()
             context.localizedReason = "sign a request from \"\(provenance.origin.displayName)\" using secret \"\(secret.name)\""
@@ -79,7 +79,11 @@ extension SmartCard {
             guard let signature = SecKeyCreateSignature(key, signatureAlgorithm, data as CFData, &signError) else {
                 throw SigningError(error: signError)
             }
-            return SignedData(data: signature as Data, requiredAuthentication: false)
+            return signature as Data
+        }
+
+        public func existingPersistedAuthenticationContext(secret: SmartCard.Secret) -> PersistedAuthenticationContext? {
+            nil
         }
 
         public func persistAuthentication(secret: SmartCard.Secret, forDuration: TimeInterval) throws {

Sources/Packages/Tests/SecretAgentKitTests/StubStore.swift

@@ -49,7 +49,7 @@ extension Stub {
             print("Public Key OpenSSH: \(OpenSSHKeyWriter().openSSHString(secret: secret))")
         }
 
-        public func sign(data: Data, with secret: Secret, for provenance: SigningRequestProvenance) throws -> SignedData {
+        public func sign(data: Data, with secret: Secret, for provenance: SigningRequestProvenance) throws -> Data {
             guard !shouldThrow else {
                 throw NSError(domain: "test", code: 0, userInfo: nil)
             }
@@ -68,7 +68,11 @@ extension Stub {
             default:
                 fatalError()
             }
-            return SignedData(data: SecKeyCreateSignature(privateKey, signatureAlgorithm, data as CFData, nil)! as Data, requiredAuthentication: false)
+            return SecKeyCreateSignature(privateKey, signatureAlgorithm, data as CFData, nil)! as Data
+        }
+
+        public func existingPersistedAuthenticationContext(secret: Stub.Secret) -> PersistedAuthenticationContext? {
+            nil
         }
 
         public func persistAuthentication(secret: Stub.Secret, forDuration duration: TimeInterval) throws {
@@ -88,6 +92,7 @@ extension Stub {
 
         let keySize: Int
         let publicKey: Data
+        let requiresAuthentication = false
         let privateKey: Data
 
         init(keySize: Int, publicKey: Data, privateKey: Data) {

Sources/Packages/Tests/SecretAgentKitTests/StubWitness.swift

@@ -17,7 +17,7 @@ func speakNowOrForeverHoldYourPeace(forAccessTo secret: AnySecret, from store: A
         }
     }
 
-func witness(accessTo secret: AnySecret, from store: AnySecretStore, by provenance: SigningRequestProvenance, requiredAuthentication: Bool) throws {
+func witness(accessTo secret: AnySecret, from store: AnySecretStore, by provenance: SigningRequestProvenance) throws {
         witness(secret, provenance)
     }
 

Sources/SecretAgent/Notifier.swift

@@ -57,7 +57,7 @@ class Notifier {
         notificationCenter.requestAuthorization(options: .alert) { _, _ in }
     }
 
-    func notify(accessTo secret: AnySecret, from store: AnySecretStore, by provenance: SigningRequestProvenance, requiredAuthentication: Bool) {
+    func notify(accessTo secret: AnySecret, from store: AnySecretStore, by provenance: SigningRequestProvenance) {
         notificationDelegate.pendingPersistableSecrets[secret.id.description] = secret
         notificationDelegate.pendingPersistableStores[store.id.description] = store
         let notificationCenter = UNUserNotificationCenter.current()
@@ -69,7 +69,7 @@ class Notifier {
         if #available(macOS 12.0, *) {
             notificationContent.interruptionLevel = .timeSensitive
         }
-        if requiredAuthentication {
+        if secret.requiresAuthentication && store.existingPersistedAuthenticationContext(secret: secret) == nil {
             notificationContent.categoryIdentifier = Constants.persistAuthenticationCategoryIdentitifier
         }
         if let iconURL = provenance.origin.iconURL, let attachment = try? UNNotificationAttachment(identifier: "icon", url: iconURL, options: nil) {
@@ -106,8 +106,8 @@ extension Notifier: SigningWitness {
     func speakNowOrForeverHoldYourPeace(forAccessTo secret: AnySecret, from store: AnySecretStore, by provenance: SigningRequestProvenance) throws {
     }
 
-    func witness(accessTo secret: AnySecret, from store: AnySecretStore, by provenance: SigningRequestProvenance, requiredAuthentication: Bool) throws {
-        notify(accessTo: secret, from: store, by: provenance, requiredAuthentication: requiredAuthentication)
+    func witness(accessTo secret: AnySecret, from store: AnySecretStore, by provenance: SigningRequestProvenance) throws {
+        notify(accessTo: secret, from: store, by: provenance)
     }
 
 }

Sources/Secretive/Preview Content/PreviewStore.swift

@@ -11,6 +11,7 @@ extension Preview {
         let name: String
         let algorithm = Algorithm.ellipticCurve
         let keySize = 256
+        let requiresAuthentication: Bool = false
         let publicKey = UUID().uuidString.data(using: .utf8)!
 
     }
@@ -35,8 +36,12 @@ extension Preview {
             self.secrets.append(contentsOf: new)
         }
 
-        func sign(data: Data, with secret: Preview.Secret, for provenance: SigningRequestProvenance) throws -> SignedData {
-            return SignedData(data: data, requiredAuthentication: false)
+        func sign(data: Data, with secret: Preview.Secret, for provenance: SigningRequestProvenance) throws -> Data {
+            return data
+        }
+
+        func existingPersistedAuthenticationContext(secret: Preview.Secret) -> PersistedAuthenticationContext? {
+            nil
         }
 
         func persistAuthentication(secret: Preview.Secret, forDuration duration: TimeInterval) throws {

Sources/Secretive/Views/SecretListItemView.swift

@@ -20,7 +20,15 @@ struct SecretListItemView: View {
         )
 
         return NavigationLink(destination: SecretDetailView(secret: secret), tag: secret.id, selection: $activeSecret) {
-            Text(secret.name)
+            if secret.requiresAuthentication {
+                HStack {
+                    Text(secret.name)
+                    Spacer()
+                    Image(systemName: "lock")
+                }
+            } else {
+                Text(secret.name)
+            }
         }.contextMenu {
             if store is AnySecretStoreModifiable {
                 Button(action: { isRenaming = true }) {