Can't decrypt NSData when running BGProcessingTask - objective-c

Question

I setup everything to run some code in the background when my app isn't active. I use BGProcessingTask.
When I Pause the program execution, and enter the command e -l objc -- (void)[[BGTaskScheduler sharedScheduler] _simulateLaunchForTaskWithIdentifier:#"com.myApp.processing"]
it tests the Process and runs my code, but it doesn't finish the job when it reaches the code to decrypt my data. I use RNCryptor to decrypt the data, but it seems like it doesn't want to run when my app is in the background.
This is the code I run:
- (void)nvmDoubleDecryptedAES256DataWithSecurityKey:(nonnull NSString*)theSecurityKey WithMasterPasswordKey:(nonnull NSString*)theMasterPassword WithCompletion:(void (^_Nullable)(NSData* _Nullable decryptedData, NSError* _Nullable error))completionBlock {
NSError *firstStatus, *secondStatus;
NSLog(#"AR - 111");
NSData *mpDecryptedData = [RNDecryptor decryptData:self withPassword:theMasterPassword error:&firstStatus];
NSLog(#"AR - 112");
if ((mpDecryptedData) && (!firstStatus)) {
NSData *skDecryptedData = [RNDecryptor decryptData:mpDecryptedData withPassword:theSecurityKey error:&secondStatus];
NSLog(#"AR - 113");
if ((skDecryptedData) && (!secondStatus)) {
if (completionBlock) completionBlock(skDecryptedData, nil);
}
else {
NSError *errorSecurityKeyIncorrect = [NSError errorWithDomain:[NVMFunctions getBundleIdentifier] code:PRLErrorCodeSecurityKeyIncorrect userInfo:#{NSLocalizedDescriptionKey:[NSString stringWithFormat:#"Security Key is incorrect | Decrypt error: %#", firstStatus]}]; //Keep this error code
if (completionBlock) completionBlock(nil, errorSecurityKeyIncorrect);
}
}
else {
NSError *errorMasterPasswordIncorrect = [NSError errorWithDomain:[NVMFunctions getBundleIdentifier] code:PRLErrorCodeMasterPasswordKeyIncorrect userInfo:#{NSLocalizedDescriptionKey:[NSString stringWithFormat:#"Master Password is incorrect | Decrypt error: %#", secondStatus]}]; //Keep this error code
if (completionBlock) completionBlock(nil, errorMasterPasswordIncorrect);
}
}
But in the logs I see i keeps hanging on AR - 111 . As soon as i reopen my app is continues with AR - 112. It seems like a big issue if I can't decrypt my data in the background...
Does anyone know a fix?
Full logs:
(lldb) e -l objc -- (void)[[BGTaskScheduler sharedScheduler] _simulateLaunchForTaskWithIdentifier:#"com.novem.Peral.processing"]
2020-06-03 21:38:06.120568+0200 Peral[14608:3145844] Simulating launch for task with identifier com.novem.Peral.processing
2020-06-03 21:38:14.539735+0200 Peral[14608:3146386] Starting simulated task: <BGProcessingTask: com.novem.Peral.processing>
2020-06-03 21:38:14.580935+0200 Peral[14608:3146383] AR - 111
AppDelegate.m:
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
[self registerBackgroundTaks];
return YES;
}
- (void)registerBackgroundTaks {
[[BGTaskScheduler sharedScheduler] registerForTaskWithIdentifier:#"com.novem.Peral.processing" usingQueue:nil launchHandler:^(__kindof BGTask * _Nonnull task) {
[self handleAppRefresh:task];
}];
}
- (void)handleAppRefresh:(BGProcessingTask *)task {
[self scheduleAppRefresh];
NSOperationQueue *queue = [[NSOperationQueue alloc] init];
[queue addOperationWithBlock: ^{
NSString *theSecurityKey = #"key";
NSString *theMasterPassword = #"passord";
[self nvmDoubleDecryptedAES256DataWithSecurityKey:theSecurityKey WithMasterPasswordKey:theMasterPassword WithCompletion:^(NSData * _Nullable decryptedData, NSError * _Nullable error) {
[task setTaskCompletedWithSuccess:!queue.isSuspended];
}];
}];
[task setExpirationHandler:^{
[queue cancelAllOperations];
}];
}
- (void)scheduleAppRefresh {
BGProcessingTaskRequest *request = [[BGProcessingTaskRequest alloc] initWithIdentifier:#"com.novem.Peral.processing"];
[request setRequiresExternalPower:YES];
[request setRequiresNetworkConnectivity:YES];
//[request setEarliestBeginDate:[NSDate dateWithTimeIntervalSinceNow:2 * 60]]; //Start after 2 minutes
NSError *requestError;
[[BGTaskScheduler sharedScheduler] submitTaskRequest:request error:&requestError];
if (requestError) NSLog(#"Exception: %#", requestError);
}
EDIT
After looking at the RNCryptor, if found out that it freezes when reaching a certain line.
+ (NSData *)keyForPassword:(NSString *)password salt:(NSData *)salt settings:(RNCryptorKeyDerivationSettings)keySettings
{
NSLog(#"RN - 124831");
NSMutableData *derivedKey = [NSMutableData dataWithLength:keySettings.keySize];
NSLog(#"RN - 124832");
// See Issue #77. V2 incorrectly calculated key for multi-byte characters.
NSData *passwordData;
NSLog(#"RN - 124833");
if (keySettings.hasV2Password) {
NSLog(#"RN - 1248331");
passwordData = [NSData dataWithBytes:[password UTF8String] length:[password length]];
}
else {
NSLog(#"RN - 1248332");
passwordData = [password dataUsingEncoding:NSUTF8StringEncoding];
}
// Use the built-in PBKDF2 if it's available. Otherwise, we have our own. Hello crazy function pointer.
NSLog(#"RN - 124834");
int result;
NSLog(#"RN - 124835");
int (*PBKDF)(CCPBKDFAlgorithm algorithm, const char *password, size_t passwordLen,
const uint8_t *salt, size_t saltLen,
CCPseudoRandomAlgorithm prf, uint rounds,
uint8_t *derivedKey, size_t derivedKeyLen);
NSLog(#"RN - 124836");
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wunreachable-code"
PBKDF = CCKeyDerivationPBKDF ?: RN_CCKeyDerivationPBKDF;
#pragma clang diagnostic pop
NSLog(#"RN - 124837");
result = PBKDF(keySettings.PBKDFAlgorithm, // algorithm
passwordData.bytes, // password
passwordData.length, // passwordLength
salt.bytes, // salt
salt.length, // saltLen
keySettings.PRF, // PRF
keySettings.rounds, // rounds
derivedKey.mutableBytes, // derivedKey
derivedKey.length); // derivedKeyLen
NSLog(#"RN - 124838");
// Do not log password here
NSAssert(result == kCCSuccess, #"Unable to create AES key for password: %d", result);
return derivedKey;
}
This is the log I get:
2020-06-04 21:37:32.238187+0200 Peral[16824:3659587] RN - 124831
2020-06-04 21:37:32.238507+0200 Peral[16824:3659587] RN - 124832
2020-06-04 21:37:32.238818+0200 Peral[16824:3659587] RN - 124833
2020-06-04 21:37:32.239046+0200 Peral[16824:3659587] RN - 1248332
2020-06-04 21:37:32.239419+0200 Peral[16824:3659587] RN - 124834
2020-06-04 21:37:32.239663+0200 Peral[16824:3659587] RN - 124835
2020-06-04 21:37:32.240287+0200 Peral[16824:3659587] RN - 124836
2020-06-04 21:37:32.240575+0200 Peral[16824:3659587] RN - 124837
so it freezes with result = PBKDF....