This commit is contained in:
Max Goedjen 2022-02-24 22:35:29 -08:00
parent e7e9f2b7f9
commit 832d82304d
No known key found for this signature in database
GPG Key ID: E58C21DD77B9B8E8
11 changed files with 60 additions and 48 deletions

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@ -113,7 +113,7 @@ extension Agent {
let dataToSign = reader.readNextChunk() let dataToSign = reader.readNextChunk()
let signed = try store.sign(data: dataToSign, with: secret, for: provenance) 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)! 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)) signedData.append(writer.lengthAndData(of: sub))
if let witness = witness { 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") Logger().debug("Agent signed request")

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@ -17,7 +17,6 @@ public protocol SigningWitness {
/// - secret: The `Secret` that will was used to sign the request. /// - secret: The `Secret` that will was used to sign the request.
/// - store: The `Store` that signed the request.. /// - store: The `Store` that signed the request..
/// - provenance: A `SigningRequestProvenance` object describing the origin of 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) throws
func witness(accessTo secret: AnySecret, from store: AnySecretStore, by provenance: SigningRequestProvenance, requiredAuthentication: Bool) throws
} }

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

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

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@ -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 }
}

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@ -20,8 +20,14 @@ public protocol SecretStore: ObservableObject, Identifiable {
/// - data: The data to sign. /// - data: The data to sign.
/// - secret: The ``Secret`` to sign with. /// - secret: The ``Secret`` to sign with.
/// - provenance: A ``SigningRequestProvenance`` describing where the request came from. /// - provenance: A ``SigningRequestProvenance`` describing where the request came from.
/// - Returns: A ``SignedData`` object, containing the signature and metadata about the signature process. /// - Returns: The signed data.
func sign(data: Data, with secret: SecretType, for provenance: SigningRequestProvenance) throws -> SignedData 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. /// Persists user authorization for access to a secret.
/// - Parameters: /// - Parameters:

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@ -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
}
}

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@ -100,7 +100,7 @@ extension SecureEnclave {
reloadSecrets() 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 let context: LAContext
if let existing = persistedAuthenticationContexts[secret], existing.valid { if let existing = persistedAuthenticationContexts[secret], existing.valid {
context = existing.context context = existing.context
@ -131,16 +131,15 @@ extension SecureEnclave {
let key = untypedSafe as! SecKey let key = untypedSafe as! SecKey
var signError: SecurityError? var signError: SecurityError?
let signingStartTime = Date()
guard let signature = SecKeyCreateSignature(key, .ecdsaSignatureMessageX962SHA256, data as CFData, &signError) else { guard let signature = SecKeyCreateSignature(key, .ecdsaSignatureMessageX962SHA256, data as CFData, &signError) else {
throw SigningError(error: signError) throw SigningError(error: signError)
} }
let signatureDuration = Date().timeIntervalSince(signingStartTime) return signature as Data
// 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 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 { public func persistAuthentication(secret: Secret, forDuration duration: TimeInterval) throws {
@ -294,7 +293,7 @@ extension SecureEnclave {
extension SecureEnclave { extension SecureEnclave {
/// A context describing a persisted authentication. /// A context describing a persisted authentication.
private struct PersistentAuthenticationContext { private struct PersistentAuthenticationContext: PersistedAuthenticationContext {
/// The Secret to persist authentication for. /// The Secret to persist authentication for.
let secret: Secret let secret: Secret
@ -302,7 +301,7 @@ extension SecureEnclave {
let context: LAContext let context: LAContext
/// An expiration date for the context. /// An expiration date for the context.
/// - Note - Monotonic time instead of Date() to prevent people setting the clock back. /// - Note - Monotonic time instead of Date() to prevent people setting the clock back.
let expiration: UInt64 let monotonicExpiration: UInt64
/// Initializes a context. /// Initializes a context.
/// - Parameters: /// - Parameters:
@ -313,12 +312,18 @@ extension SecureEnclave {
self.secret = secret self.secret = secret
self.context = context self.context = context
let durationInNanoSeconds = Measurement(value: duration, unit: UnitDuration.seconds).converted(to: .nanoseconds).value 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. /// A boolean describing whether or not the context is still valid.
var valid: Bool { 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)
} }
} }

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@ -44,7 +44,7 @@ extension SmartCard {
fatalError("Keys must be deleted on the smart card.") 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() } guard let tokenID = tokenID else { fatalError() }
let context = LAContext() let context = LAContext()
context.localizedReason = "sign a request from \"\(provenance.origin.displayName)\" using secret \"\(secret.name)\"" 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 { guard let signature = SecKeyCreateSignature(key, signatureAlgorithm, data as CFData, &signError) else {
throw SigningError(error: signError) 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 { public func persistAuthentication(secret: SmartCard.Secret, forDuration: TimeInterval) throws {

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

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@ -36,8 +36,8 @@ extension Preview {
self.secrets.append(contentsOf: new) self.secrets.append(contentsOf: new)
} }
func sign(data: Data, with secret: Preview.Secret, for provenance: SigningRequestProvenance) throws -> SignedData { func sign(data: Data, with secret: Preview.Secret, for provenance: SigningRequestProvenance) throws -> Data {
return SignedData(data: data, requiredAuthentication: false) return data
} }
func persistAuthentication(secret: Preview.Secret, forDuration duration: TimeInterval) throws { func persistAuthentication(secret: Preview.Secret, forDuration duration: TimeInterval) throws {