iOS KeyChain Items not being updated between multiple targets of an app

Question

I am building an app where people need to be able to share a photo from the iOS photos app. To do so people need to be logged in into the app.

So I created a new iOS target for the sharing. Now I am using KeychainItemWrapper to store user credentials. So both the main target as wel as the share-sheet target use the iOS Keychain to retrieve the login information.

Now when I log out from the main app, and then login as a different user, and after that I start the share sheet, it looks like the share sheet still has the old data from the previous user.

How is that possible? How can I make sure both targets always use the latest and greatest data from the keychain?

#import "KeychainManager.h"
#import "KeychainItemWrapper.h"

NSString * const CREDENTIALS_IDENTIFIER = @"credentials";
NSString * const COOKIES_IDENTIFIER = @"cookies";

static KeychainManager *keychainManager;

@implementation KeychainManager

+ (instancetype)sharedCredentailsManager {
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        keychainManager = [[KeychainManager alloc] init];
    });
    return keychainManager;
}

#pragma mark - Getter
- (KeychainItemWrapper *)credentialsKeychainItem {
    return [[KeychainItemWrapper alloc] initWithIdentifier:CREDENTIALS_IDENTIFIER accessGroup:nil];
}

- (KeychainItemWrapper *)cookiesKeychainItem {
    return [[KeychainItemWrapper alloc] initWithIdentifier:COOKIES_IDENTIFIER accessGroup:nil];
}

- (NSString *)domainName {
    NSString *domainName = [self.credentialsKeychainItem objectForKey:(__bridge id)(kSecAttrService)];
    return (domainName.length > 0) ? domainName : @"";
}

- (NSString *)userName {
    NSString *userName = [self.credentialsKeychainItem objectForKey:(__bridge id)(kSecAttrAccount)];
    return (userName.length > 0) ? userName : @"";
}

- (NSString *)password {
    NSData *password = [self.credentialsKeychainItem objectForKey:(__bridge id)(kSecValueData)];
    if ([password isKindOfClass:[NSString class]] && password.length > 0) {
        return (NSString *)password;
    } else if ([password isKindOfClass:[NSData class]] && password.length > 0) {
        NSString *passwordString = [[NSString alloc] initWithData:password encoding:NSUTF8StringEncoding];
        return (passwordString.length > 0) ? password : @"";
    } else {
        return @"";
    }
}

- (NSArray *)cookies {
    NSLog(@"Getting cookies");
    NSData *cookieData = [self.cookiesKeychainItem objectForKey:(__bridge id)(kSecAttrAccount)];
    if ([cookieData isKindOfClass:[NSData class]] && cookieData.length > 0) {
        NSArray *array = [NSKeyedUnarchiver unarchiveObjectWithData:cookieData];
        NSLog(@"%lu cookies in keychain", (unsigned long)array.count);
        return array;
    } else {
        NSLog(@"No cookies found in KeyChain");
        return nil;
    }
}

#pragma mark - Setter
- (void)setDomainName:(NSString *)domainName {
    [self.credentialsKeychainItem setObject:domainName forKey:(__bridge id)(kSecAttrService)];
}

- (void)setUserName:(NSString *)userName {
    [self.credentialsKeychainItem setObject:userName forKey:(__bridge id)(kSecAttrAccount)];
}

- (void)setPassword:(NSString *)password {
    [self.credentialsKeychainItem setObject:password forKey:(__bridge id)(kSecValueData)];
}

- (void)setCookies:(NSArray *)cookies {
    NSMutableArray *mutableCookies = [[NSMutableArray alloc] init];
    for (NSHTTPCookie *cookie in cookies) {
        NSLog(@"storing cookie: %@", cookie);
        NSDictionary *cookieProperties = cookie.properties;
        [mutableCookies addObject:cookieProperties];
    }
    NSArray *unmutableCookies = [mutableCookies copy];
    NSData * encodedData = [NSKeyedArchiver archivedDataWithRootObject:unmutableCookies];
    [self.cookiesKeychainItem setObject:encodedData forKey:(__bridge id)(kSecAttrAccount)];
}

# pragma mark - Clear data
- (void)clearAll {
    [self clearCredentials];
    [self clearCookies];
}

- (void)clearCredentials {
    [self.credentialsKeychainItem resetKeychainItem];
}

- (void)clearCookies {
    [self.cookiesKeychainItem resetKeychainItem];
}

@end

So the symptoms are that the functions to get username, password, domain or cookies all give different results between different targets of the same app.

Answer 1

I found the problem. I had to setup Keychain sharing in the entitlements of both targets.

A guide on how to set this is found here:

http://evgenii.com/blog/sharing-keychain-in-ios/

Then you have to store your Keychain items in an access group. When I tried that, the KeychainItemWrapper gave some Assertion Failures when I wanted to store something in the Keychain, which I then could solve using the following link: KeychainItemWrapper error when specifying an access group