Crash due to Fatal error • KronosNTPPacket.dateToNTPFormat(_:)

[saad352]

Stack trace

We have started to receive this crash from Datadog code with this message. Fatal error: Double value cannot be converted to UInt32 because the result would be greater than UInt32.max

The full crash report is as follows with some information redacted.

CrashReporter Key:  6685c0a40ba771116e66b298b9d504e9156eb9cc
Hardware Model:     iPhone14,7
OS Version:         iOS 26.1
Exception Type:     EXC_BREAKPOINT 
Exception Subtype:  KERN_INVALID_ADDRESS

Fatal error: Double value cannot be converted to UInt32 because the result would be greater than UInt32.max

0  libswiftCore.dylib +0x135bf8 _assertionFailure(_:_:file:line:flags:)
1  Glovo +0x1687acc             KronosNTPPacket.dateToNTPFormat(_:)
2  Glovo +0x1686dc0             KronosNTPPacket.prepareToSend(transmitTime:)
3  Glovo +0x1685324             closure #1 in KronosNTPClient.sendAsyncUDPQuery(to:port:timeout:completion:)
4  Glovo +0x16855c8             @objc closure #1 in KronosNTPClient.sendAsyncUDPQuery(to:port:timeout:completion:)
5  CoreFoundation +0xc8084      ___CFSocketPerformV0
6  CoreFoundation +0x68f20      ___CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__
7  CoreFoundation +0x68e94      ___CFRunLoopDoSource0
8  CoreFoundation +0x46b2c      ___CFRunLoopDoSources0
9  CoreFoundation +0x1d6d4      ___CFRunLoopRun
10 CoreFoundation +0x1ca68      __CFRunLoopRunSpecificWithOptions
11 GraphicsServices +0x1494     _GSEventRunModal
12 UIKitCore +0x9dba0           -[UIApplication _run]
13 UIKitCore +0x46a74           _UIApplicationMain
14 Glovo +0x299f0               main (AppDelegate.swift:70:7)
15 dyld +0x4e24                 start

The crash seems to be happening in this function.

Reproduction steps

I have not tired to reproduce this. But I believe the error message is quite clear on what could be the reproduction steps.

Volume

For now less. But it is a recurrent crash for users at the start of app.

Affected SDK versions

2.30.1

Latest working SDK version

2.30.1

Does the crash manifest in the latest SDK version?

No

Deployment Target

Minimum Deployment Target is iOS 16

Device Information

No response

Other relevant information

No response

[maxep]

Hey @saad352 👋

Thanks for the report, I can confirm that Kronos code is at risk of overflows here and here. We can plan a fix to make it safer.

Although, this code has been there for very long time and this is the first report on this. An overflow in KronosNTPPacket.dateToNTPFormat(_:) can happen if the system clock is set far in the future or if an invalid date is passed. Are you able to identify if this happens consistently under specific conditions (e.g., modified system time)?

Thanks!

[saad352]

Hey @maxep

Thanks for checking.

Are you able to identify if this happens consistently under specific conditions (e.g., modified system time)?

From the logs and breadcrumbs, I see that this is happening for users as soon as they start the app. Not 100% sure that the system time is modified or not. But form the logic looks like that time is modified.

It would be nice if you can cover this scenario to not crash the app at least but report in o11y. :thanks:

[maxep]

Yes, totally :) I have logged a ticket to fix 👍