util: fix deserialize buffer overflow

[alonbl]

Missing check for source file increment.

Reported-by: Aarnav Bos [email protected]

[alonbl]

@selvanair thank you so much for the review, I've modified the implementation to use macros, I hope now all is ok.

[selvanair]

Looks good to me if returning a wrong value of *max is okay in case of error. Let's see whether the fuzzer can still crash it!

[R9295]

@selvanair @alonbl the fix also looks good from the fuzzing side!

[alonbl]

Thank you all!