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KeychainUtils for Apple Platforms (iOS, macOS, watchOS, tvOS)
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/* Note: There are a lot of assumption on the type of Keychain element that are | |
* inserted, etc. You should adjust the code accordingly to your needs. */ | |
/* Note2: Indent spacing is **3** tabs, but gist does not propose the option… */ | |
import Foundation | |
import Security | |
struct Keychain { | |
enum Error : Swift.Error { | |
case secError(code: OSStatus, message: String?) | |
case internalError | |
} | |
static func getStoredData(withIdentifier identifier: String, accessGroup: String? = nil, username: String = "") throws -> Data? { | |
var searchResult: CFTypeRef? | |
var query = baseQuery(forIdentifier: identifier, accessGroup: accessGroup, username: username) | |
query[kSecMatchLimit as String] = kSecMatchLimitOne | |
query[kSecReturnData as String] = kCFBooleanTrue | |
query[kSecReturnRef as String] = kCFBooleanFalse | |
query[kSecReturnPersistentRef as String] = kCFBooleanFalse | |
query[kSecReturnAttributes as String] = kCFBooleanFalse | |
let error = SecItemCopyMatching(query as CFDictionary, &searchResult) | |
switch error { | |
case errSecSuccess: | |
guard let result = searchResult as? Data else { | |
throw Error.internalError | |
} | |
return result | |
case errSecItemNotFound: | |
return nil | |
default: | |
throw secErrorFrom(statusCode: error) | |
} | |
} | |
/** Setting data to nil just removes the entry in the keychain. */ | |
static func setStoredData(_ data: Data?, withIdentifier identifier: String, accessGroup: String? = nil, username: String = "") throws { | |
guard let data = data else { | |
try removeStoredData(withIdentifier: identifier, accessGroup: accessGroup, username: username) | |
return | |
} | |
var query = baseQuery(forIdentifier: identifier, accessGroup: accessGroup, username: username) | |
query[kSecAttrAccessible as String] = kSecAttrAccessibleAfterFirstUnlock | |
query[kSecClass as String] = kSecClassGenericPassword | |
query[kSecMatchLimit as String] = kSecMatchLimitOne | |
query[kSecReturnData as String] = kCFBooleanFalse | |
query[kSecReturnRef as String] = kCFBooleanFalse | |
query[kSecReturnPersistentRef as String] = kCFBooleanFalse | |
query[kSecReturnAttributes as String] = kCFBooleanTrue | |
query[kSecAttrIsInvisible as String] = kCFBooleanFalse | |
query[kSecValueData as String] = data | |
let updatedProperties = [kSecValueData as String: data] | |
/* First we try and update the existing property. If the property does not | |
* exist, we will process the error and use SecItemAdd */ | |
var saveError = SecItemUpdate(query as CFDictionary, updatedProperties as CFDictionary) | |
if saveError == errSecItemNotFound { | |
/* We don't have a previous entry for the given username, keychain | |
* identifier and access group. Let’s use SecItemAdd. */ | |
var saveQuery = query | |
saveQuery[kSecValueData as String] = data | |
saveError = SecItemAdd(saveQuery as CFDictionary, nil) | |
} | |
if saveError != errSecSuccess { | |
throw secErrorFrom(statusCode: saveError) | |
} | |
/* Defensive programming! Did we actually set the data correctly? */ | |
assert((try? getStoredData(withIdentifier: identifier, accessGroup: accessGroup, username: username)) == data) | |
} | |
static func removeStoredData(withIdentifier identifier: String, accessGroup: String? = nil, username: String = "") throws { | |
let query = baseQuery(forIdentifier: identifier, accessGroup: accessGroup, username: username) | |
let error = SecItemDelete(query as CFDictionary) | |
switch error { | |
case errSecSuccess, errSecItemNotFound /* If the item is not found, we consider the deletion has been successful */: | |
return | |
default: | |
throw secErrorFrom(statusCode: error) | |
} | |
} | |
#if !os(macOS) | |
/* Clearing the keychain only makes sense on a fully sandboxed environment | |
* (iOS, watchOS, etc.). */ | |
static func clearKeychain() throws { | |
let query = [kSecClass as String: kSecClassGenericPassword] | |
let error = SecItemDelete(query as CFDictionary) | |
switch error { | |
case errSecSuccess, errSecItemNotFound: | |
return | |
default: | |
throw secErrorFrom(statusCode: error) | |
} | |
} | |
#endif | |
/* *************** | |
MARK: - Private | |
*************** */ | |
private static func baseQuery(forIdentifier identifier: String, accessGroup: String?, username: String) -> [String: Any] { | |
var res = [String: Any]() | |
res[kSecClass as String] = kSecClassGenericPassword | |
// res[kSecAttrGeneric as String] = identifier | |
res[kSecAttrService as String] = identifier | |
res[kSecAttrAccount as String] = username | |
#if !os(iOS) || !targetEnvironment(simulator) | |
/* We ignore the access group if target is the iPhone simulator. See | |
* the GenericKeychain Apple example in the docs for an explanation on | |
* why we do this. */ | |
if let accessGroup = accessGroup { | |
res[kSecAttrAccessGroup as String] = accessGroup | |
} | |
#endif | |
return res | |
} | |
private static func secErrorFrom(statusCode: OSStatus) -> Error { | |
#if os(macOS) | |
return .secError(code: statusCode, message: SecCopyErrorMessageString(statusCode, nil /* reserved for future use */) as String?) | |
#else | |
return .secError(code: statusCode, message: nil) | |
#endif | |
} | |
private init() {} | |
} |
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