Invalid Opcode Response Detection to prevent Crash #480
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The following Stack Trace happens in nRF Connect 2.5.1: Thread 13 name: Thread 13 Crashed: 0 nRF-Connect 0x0000000100f77410 closure NordicSemiconductor#1 in SecureDFUPeripheral.selectCommandObject() + 384 (SecureDFUPeripheral.swift:0) 1 nRF-Connect 0x0000000100f772d8 closure NordicSemiconductor#1 in SecureDFUPeripheral.selectCommandObject() + 72 (SecureDFUPeripheral.swift:187) 2 nRF-Connect 0x0000000100f6d500 specialized SecureDFUControlPoint.peripheral(_:didUpdateValueFor:error:) + 1436 (SecureDFUControlPoint.swift:621) 3 nRF-Connect 0x0000000100f6bc8c @objc SecureDFUControlPoint.peripheral(_:didUpdateNotificationStateFor:error:) + 108 4 CoreBluetooth 0x00000001be97b64c -[CBPeripheral handleAttributeEvent:args:attributeSelector:delegateSelector:delegateFlag:] + 188 (CBPeripheral.m:804) 5 CoreBluetooth 0x00000001be97b7f0 -[CBPeripheral handleCharacteristicEvent:characteristicSelector:delegateSelector:delegateFlag:] + 124 (CBPeripheral.m:826) 6 CoreBluetooth 0x00000001be977994 -[CBPeripheral handleMsg:args:] + 600 (CBPeripheral.m:233) 7 CoreBluetooth 0x00000001be961af0 -[CBCentralManager handleMsg:args:] + 192 (CBCentralManager.m:1451) 8 CoreBluetooth 0x00000001be9a22b8 -[CBManager xpcConnectionDidReceiveMsg:args:] + 208 (CBManager.m:428) 9 CoreBluetooth 0x00000001be9916c0 __30-[CBXpcConnection _handleMsg:]_block_invoke + 68 (CBXpcConnection.m:370) 10 libdispatch.dylib 0x000000019fe16e68 _dispatch_call_block_and_release + 32 (init.c:1517) 11 libdispatch.dylib 0x000000019fe18a2c _dispatch_client_callout + 20 (object.m:560) 12 libdispatch.dylib 0x000000019fe20124 _dispatch_lane_serial_drain + 668 (inline_internal.h:2622) 13 libdispatch.dylib 0x000000019fe20cb4 _dispatch_lane_invoke + 444 (queue.c:3944) 14 libdispatch.dylib 0x000000019fe20000 _dispatch_lane_serial_drain + 376 (inline_internal.h:0) 15 libdispatch.dylib 0x000000019fe20cb4 _dispatch_lane_invoke + 444 (queue.c:3944) 16 libdispatch.dylib 0x000000019fe20000 _dispatch_lane_serial_drain + 376 (inline_internal.h:0) 17 libdispatch.dylib 0x000000019fe20c80 _dispatch_lane_invoke + 392 (queue.c:3944) 18 libdispatch.dylib 0x000000019fe2b500 _dispatch_workloop_worker_thread + 648 (queue.c:6732) 19 libsystem_pthread.dylib 0x000000021110a0bc _pthread_wqthread + 288 (pthread.c:2599) 20 libsystem_pthread.dylib 0x0000000211109e5c start_wqthread + 8 Quick analysis shows we're force-unwrapping SecureDFUResponse's maxSize, offset and crc. The obvious fix would be to just guard those properties and if they're not there, to report an Error. But the code-path leading to this code getting executed suggests we might be executing the callback for the wrong type of response, so we're going to sacrifice killing the bug in exchange for perhaps learning new information regarding the root cause of the issue.
philips77
approved these changes
May 27, 2022
This was referenced Jun 29, 2022
Closed
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The following Stack Trace happens in nRF Connect 2.5.1:
Quick analysis shows we're force-unwrapping
SecureDFUResponse'smaxSize,offsetandcrc. The obvious fix would be to just guard those properties and, if they're not there, to report an Error. But the code-path leading to this code getting executed suggests we might be executing the callback for the wrong type of response, so we're going to sacrifice killing the bug in exchange for perhaps learning new information regarding the root cause of the issue.