iOS Keychain writing value results in error code -34018

Question

I have an iOS application that stores some sensitive information in the keychain. While writing values into the keychain, I am getting error code -34018.

I am currently using Apple's iOS KeyChainItemWrapper class.

Both of the following lines of code receive the same error code.

OSStatus res1 = SecItemCopyMatching((__bridge CFDictionaryRef)genericPasswordQuery, (CFTypeRef *)&attributes); OSStatus res = SecItemUpdate((__bridge CFDictionaryRef)updateItem, (__bridge CFDictionaryRef)tempCheck); 

This issue does not occur every time, but intermittently. Once I get this error, I am no longer able to write any values to the keychain.

I have printed the error description like so:

NSError *error = [NSError errorWithDomain:NSOSStatusErrorDomain code:res userInfo:nil]; 

and this is what the error prints out:

Error: Error Domain=NSOSStatusErrorDomain Code=-34018 "The operation couldn’t be completed. (OSStatus error -34018.)" 

Answer 1

Seems like this is a bug in Keychain, which only appears when you launch your app from xcode. See here: https://github.com/soffes/sskeychain/issues/52

We debugged it a lot and it seems an issue accessing the keychain when the app is launched from the background. This is only happening with the debugger (i.e. when launched from Xcode). We think the issue might be related in our case to the debugger keeping alive the app even if it should be killed by the OS. We tried in fact to run the app and then put it in background and launch many other app to occupy RAM. With the debugger the bug came up when resuming the app from the background, while without the debugger it didn't (we did run at least 10 tests each).

Answer 2

If someone will come here back with this error and XCode8 with iOS10, probably you have to enable KeyChain Share in the tab Capabilities: