SecItemCopyMatching返回空字典

由于某些原因，我在调用OSX 10.8.4上的SecItemCopyMatching时收到了空字典。相应的项目位于钥匙串中并包含用户名和密码。 SecItemCopyMatching创建它（errSecSuccess），但结果字典只包含0个条目。我希望它至少有用户名和密码数据，那么我的请求有什么问题？SecItemCopyMatching返回空字典

OSStatus status; 
NSMutableDictionary *query = [NSMutableDictionary dictionary]; 
[query setObject:(id)kSecClassGenericPassword forKey:(id)kSecClass]; 
[query setObject:(id)kSecReturnAttributes forKey:(id)kCFBooleanTrue]; 
[query setObject:@"MyService" forKey:(id)kSecAttrService]; 

CFDictionaryRef dictRef = NULL; 
status = SecItemCopyMatching((__bridge CFDictionaryRef)query, (CFTypeRef *)&dictRef); 
if (status != errSecSuccess) { 
    CFStringRef errorRef = SecCopyErrorMessageString(status, NULL); 
    NSLog(@"%s: %@", __FUNCTION__, (__bridge NSString *)errorRef); 
    CFRelease(errorRef); 
    return nil; 
} 

// --> dictRef empty 

if (dictRef != NULL) CFRelease(dictRef);

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来源

2013-06-27 Gamadril

我不能，为什么你得到一个空的字典回来一看便知，但密码没有被返回并不奇怪。 kSecReturnAttributes的头文件说：_Specifies一个字典键，其值为CFBooleanRef类型。值为kCFBooleanTrue表示应该返回一个项目（在CFDictionaryRef中）的（未加密的）属性._ – bdash

你是对的，它没有要求允许访问钥匙串。在请求中有一个愚蠢的错误：[查询setObject：（id）kCFBooleanTrue forKey：（id）kSecReturnAttributes]; – Gamadril

有在请求一个错误。我混淆了关键和对象。

[query setObject:(id)kSecReturnAttributes forKey:(id)kCFBooleanTrue];

必须

[query setObject:(id)kCFBooleanTrue forKey:(id)kSecReturnAttributes];

然而由于bdash指出的那样，将返回唯一的非加密特性，如用户名。要获得密码有必要的传递

[query setObject:(id)kCFBooleanTrue forKey:(id)kSecReturnData];

所以在这里我现在有另一个请求：

OSStatus status; 
NSMutableDictionary *query = [NSMutableDictionary dictionary]; 
[query setObject:(id)kSecClassGenericPassword forKey:(id)kSecClass]; 
[query setObject:(id)kCFBooleanTrue forKey:(id)kSecReturnAttributes]; 
[query setObject:(id)kSecMatchLimitOne forKey:(id)kSecMatchLimit]; 
[query setObject:@"MyService" forKey:(id)kSecAttrService]; 

// get username 
CFDictionaryRef dictRef = NULL; 
status = SecItemCopyMatching((__bridge CFDictionaryRef)query, (CFTypeRef *)&dictRef); 
if (status != errSecSuccess) { 
    CFStringRef errorRef = SecCopyErrorMessageString(status, NULL); 
    NSLog(@"%s: %@", __FUNCTION__, (__bridge NSString *)errorRef); 
    CFRelease(errorRef); 
    return nil; 
} 

NSString *username = (__bridge NSString *)CFDictionaryGetValue(dictRef, kSecAttrAccount); 
CFRelease(dictRef); 

// get password 
[query removeObjectForKey:(id)kSecReturnAttributes]; 
[query setObject:(id)kCFBooleanTrue forKey:(id)kSecReturnData]; 
CFDataRef dataRef = NULL; 
status = SecItemCopyMatching((__bridge CFDictionaryRef)query, (CFTypeRef *)&dataRef); 
if (status != errSecSuccess) { 
    CFStringRef errorRef = SecCopyErrorMessageString(status, NULL); 
    NSLog(@"%s: %@", __FUNCTION__, (__bridge NSString *)errorRef); 
    CFRelease(errorRef); 
    return nil; 
} 

NSString *password = [[NSString alloc] initWithData:(__bridge NSData *)(dataRef) encoding:NSUTF8StringEncoding]; 
CFRelease(dataRef);

来源

2013-06-27 08:30:03 Gamadril

SecItemCopyMatching返回空字典

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