Question

我正在尝试使用此Apple示例代码中提供的KeychainWrapper类：https://developer.apple.com/library/content/samplecode/GenericKeychain/

在示例应用程序中，该类的init方法以：

开头

- (id)initWithIdentifier: (NSString *)identifier accessGroup:(NSString *) accessGroup;
{
    if (self = [super init])
    {
        // Begin Keychain search setup. The genericPasswordQuery leverages the special user
        // defined attribute kSecAttrGeneric to distinguish itself between other generic Keychain
        // items which may be included by the same application.
        genericPasswordQuery = [[NSMutableDictionary alloc] init];

        [genericPasswordQuery setObject:(id)kSecClassGenericPassword forKey:(id)kSecClass];
        [genericPasswordQuery setObject:identifier forKey:(id)kSecAttrGeneric];

在示例应用程序中，它使用两个值作为标识符字符串。 “密码”和“帐号”。在我的代码中实现类时，我使用了一些自定义标识符，但代码不起作用。对SecItemAdd（）的调用失败。经过一些测试后，似乎使用“密码”和“帐号”以外的值作为标识符不起作用。

是否有人知道允许的值和/或是否可以为您的钥匙串项目设置自定义标识符？

Answer 1

好的，我在这篇博文Keychain duplicate item when adding password

中找到了解决方案

总而言之，问题在于GenericKeychain示例应用程序使用存储在kSecAttrGeneric密钥中的值作为钥匙串项的标识符，而实际上这不是API用于确定唯一钥匙串项的内容。您需要使用唯一值设置的键是kSecAttrAccount键和/或kSecAttrService键。

您可以重写KeychainItemWrapper的启动器，这样您就不需要通过更改这些行来更改任何其他代码：

变化：

[genericPasswordQuery setObject:identifier forKey:(id)kSecAttrGeneric];

到：

[genericPasswordQuery setObject:identifier forKey:(id)kSecAttrAccount];

并改变：

[keychainItemData setObject:identifier forKey:(id)kSecAttrGeneric];

为：

[keychainItemData setObject:identifier forKey:(id)kSecAttrAccount];

或者，你可以做我做的事情并写一个新的启动器，它带有两个识别键：

编辑：对于使用ARC的人（您现在应该是这样），请检查nycynik's answer以获取所有正确的桥接符号

- (id)initWithAccount:(NSString *)account service:(NSString *)service accessGroup:(NSString *) accessGroup;
{
    if (self = [super init])
    {
        NSAssert(account != nil || service != nil, @"Both account and service are nil.  Must specifiy at least one.");
        // Begin Keychain search setup. The genericPasswordQuery the attributes kSecAttrAccount and 
       // kSecAttrService are used as unique identifiers differentiating keychain items from one another
        genericPasswordQuery = [[NSMutableDictionary alloc] init];

        [genericPasswordQuery setObject:(id)kSecClassGenericPassword forKey:(id)kSecClass];

        [genericPasswordQuery setObject:account forKey:(id)kSecAttrAccount];
        [genericPasswordQuery setObject:service forKey:(id)kSecAttrService];

        // The keychain access group attribute determines if this item can be shared
        // amongst multiple apps whose code signing entitlements contain the same keychain access group.
        if (accessGroup != nil)
        {
#if TARGET_IPHONE_SIMULATOR
            // Ignore the access group if running on the iPhone simulator.
            // 
            // Apps that are built for the simulator aren't signed, so there's no keychain access group
            // for the simulator to check. This means that all apps can see all keychain items when run
            // on the simulator.
            //
            // If a SecItem contains an access group attribute, SecItemAdd and SecItemUpdate on the
            // simulator will return -25243 (errSecNoAccessForItem).
#else            
            [genericPasswordQuery setObject:accessGroup forKey:(id)kSecAttrAccessGroup];
#endif
        }

        // Use the proper search constants, return only the attributes of the first match.
        [genericPasswordQuery setObject:(id)kSecMatchLimitOne forKey:(id)kSecMatchLimit];
        [genericPasswordQuery setObject:(id)kCFBooleanTrue forKey:(id)kSecReturnAttributes];

        NSDictionary *tempQuery = [NSDictionary dictionaryWithDictionary:genericPasswordQuery];

        NSMutableDictionary *outDictionary = nil;

        if (! SecItemCopyMatching((CFDictionaryRef)tempQuery, (CFTypeRef *)&outDictionary) == noErr)
        {
            // Stick these default values into keychain item if nothing found.
            [self resetKeychainItem];

            //Adding the account and service identifiers to the keychain
            [keychainItemData setObject:account forKey:(id)kSecAttrAccount];
            [keychainItemData setObject:service forKey:(id)kSecAttrService];

            if (accessGroup != nil)
            {
#if TARGET_IPHONE_SIMULATOR
                // Ignore the access group if running on the iPhone simulator.
                // 
                // Apps that are built for the simulator aren't signed, so there's no keychain access group
                // for the simulator to check. This means that all apps can see all keychain items when run
                // on the simulator.
                //
                // If a SecItem contains an access group attribute, SecItemAdd and SecItemUpdate on the
                // simulator will return -25243 (errSecNoAccessForItem).
#else            
                [keychainItemData setObject:accessGroup forKey:(id)kSecAttrAccessGroup];
#endif
            }
        }
        else
        {
            // load the saved data from Keychain.
            self.keychainItemData = [self secItemFormatToDictionary:outDictionary];
        }

        [outDictionary release];
    }

    return self;
}

希望这可以帮助其他人！

Answer 2

与上述相同，但适用于ARC。谢谢西蒙

- (id)initWithAccount:(NSString *)account service:(NSString *)service accessGroup:(NSString *) accessGroup;

{
    if (self = [super init])
    {
        NSAssert(account != nil || service != nil, @"Both account and service are nil.  Must specifiy at least one.");
        // Begin Keychain search setup. The genericPasswordQuery the attributes kSecAttrAccount and
        // kSecAttrService are used as unique identifiers differentiating keychain items from one another
        genericPasswordQuery = [[NSMutableDictionary alloc] init];

        [genericPasswordQuery setObject:(__bridge id)kSecClassGenericPassword forKey:(__bridge id)kSecClass];

        [genericPasswordQuery setObject:account forKey:(__bridge id)kSecAttrAccount];
        [genericPasswordQuery setObject:service forKey:(__bridge id)kSecAttrService];

        // The keychain access group attribute determines if this item can be shared
        // amongst multiple apps whose code signing entitlements contain the same keychain access group.
        if (accessGroup != nil)
        {
#if TARGET_IPHONE_SIMULATOR
            // Ignore the access group if running on the iPhone simulator.
            //
            // Apps that are built for the simulator aren't signed, so there's no keychain access group
            // for the simulator to check. This means that all apps can see all keychain items when run
            // on the simulator.
            //
            // If a SecItem contains an access group attribute, SecItemAdd and SecItemUpdate on the
            // simulator will return -25243 (errSecNoAccessForItem).
#else
            [genericPasswordQuery setObject:accessGroup forKey:(__bridge id)kSecAttrAccessGroup];
#endif
        }

        // Use the proper search constants, return only the attributes of the first match.
        [genericPasswordQuery setObject:(__bridge id)kSecMatchLimitOne forKey:(__bridge id)kSecMatchLimit];
        [genericPasswordQuery setObject:(__bridge id)kCFBooleanTrue forKey:(__bridge id)kSecReturnAttributes];

        NSDictionary *tempQuery = [NSDictionary dictionaryWithDictionary:genericPasswordQuery];

        CFMutableDictionaryRef outDictionary = NULL;

        if (! SecItemCopyMatching((__bridge CFDictionaryRef)tempQuery, (CFTypeRef *)&outDictionary) == noErr)
        {
            // Stick these default values into keychain item if nothing found.
            [self resetKeychainItem];

            //Adding the account and service identifiers to the keychain
            [keychainItemData setObject:account forKey:(__bridge id)kSecAttrAccount];
            [keychainItemData setObject:service forKey:(__bridge id)kSecAttrService];

            if (accessGroup != nil)
            {
#if TARGET_IPHONE_SIMULATOR
                // Ignore the access group if running on the iPhone simulator.
                //
                // Apps that are built for the simulator aren't signed, so there's no keychain access group
                // for the simulator to check. This means that all apps can see all keychain items when run
                // on the simulator.
                //
                // If a SecItem contains an access group attribute, SecItemAdd and SecItemUpdate on the
                // simulator will return -25243 (errSecNoAccessForItem).
#else
                [keychainItemData setObject:accessGroup forKey:(__bridge id)kSecAttrAccessGroup];
#endif
            }
        }
        else
        {
            // load the saved data from Keychain.
            keychainItemData = [self secItemFormatToDictionary:(__bridge NSDictionary *)outDictionary];
        }

        if(outDictionary) CFRelease(outDictionary);
    }

    return self;
}

Answer 3

Simon几乎解决了我的问题，因为在更改KeychainItemWrapper.m之后，我遇到了从钥匙串获取数据和设置数据的问题。所以在将它添加到KeychainItemWrapper.m之后，我用它来获取和存储项目：

KeychainItemWrapper *keychainItem = [[KeychainItemWrapper alloc] initWithAccount:@"Identfier" service:@"AppName" accessGroup:nil];
[keychainItem setObject:@"some value" forKey:(__bridge id)kSecAttrGeneric];
NSString *value = [keychainItem objectForKey: (__bridge id)kSecAttrGeneric];

因为[keychainItem objectForKey: (__bridge id)kSecAttrService]正在返回帐户（在此示例中为@"Identifier"）这是有意义的，但我花了一些时间才意识到我需要使用kSecAttrGeneric从包装器中获取数据。

iOS Keychain Services：只允许kSecAttrGeneric Key的特定值？

3 个答案: