Prevent crash when valueDecoded is nil

[marinofelipe]

Hello there 👋.

We at GetYourGuide are using the Adjust iOS SDK.

We've been experiencing a crash, and we found that it can happen when handling a "malformed" URL.

The crash occurs in ADJActivityHandler, when it fails to decode a query string parameter value.
The nil decodedValue then gets added to the adjustDeepLinks dictionary, with
[adjustDeepLinks setObject:valueDecoded forKey:keyWOutPrefix];. This causes a crash.

Crash message example:

Fatal Exception: NSInvalidArgumentException
*** -[__NSDictionaryM setObject:forKey:]: object cannot be nil (key: deeplink)
-[ADJActivityHandler readDeeplinkQueryStringI:queryString:adjustDeepLinks:attribution:]

We added validation to prevent this from happening, returning NO if valueDecoded is nil.

It is worth mentioning that the valueDecoded NSString pointer can be a nil value as adjUrlDecode uses the native function CFURLCreateStringByReplacingPercentEscapes which can return NULL if it fails to convert the percent escapes to characters.

A new CFString object, or NULL if the percent escapes cannot be converted to characters, assuming UTF-8 encoding.

We hope that this can help prevent crashes when, for example, an NSURL has percent escapes using UTF-16 encoding.

[uerceg]

Hi @marinofelipe

And sorry for a bit delayed reply on this one. Thanks for the PR! We'll add it to our next iOS SDK update. Will keep you posted in here.

Cheers

[marinofelipe]

Hi @uerceg,

No problem at all. That's nice, thanks for letting me know. Cheers!

[uerceg]

Replaced by #414.

Thank you one more time! 🍺