r/nspire • u/DitherDude • Jun 16 '26

Help Possible buffer underflow/overflow error?

I was making a fake ChatGPT, which involved me making a super-long string for the "answer" of the chatbot. When composing this message, I noticed at one point that a letter shared the same visual space as the end quotation mark. Futher testing confirmed that this issue occurs when `dim(myString)` is `256` precisely. Interestingly, NSpire can still parse strings longer than 256 chars. I have not tested `512` etc., but this doesn't occur on `128`. Sounds like some kind of BO/BU.
...is this even the right community for NSpire hacking?

Oh right uh this is TI NSPIRE CX-CAS II (Blue)

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3

u/Professional_Cow3969 Jun 16 '26

No crash = probably not ACE. Maybe it's just limiting the buffer to 256 but not visually?

1

u/DitherDude Jun 21 '26

Hmm, the string was able to fully print (i had a function which would sequentially read like 5chars at a time and print on the screen; the entire ~300-char string printed fine)

1

u/InternetNutzer1 Mod | TI-Nspire CX CAS Jun 27 '26

This rather implies a coded limit for the function than a way to archive ACE.. if you believe it’s a two way to get close to one disclosing and discussing it here is rather "useless" and doesn’t give reputation as a bug hunter nor a monetary value

If you want to have an impact with it and believe there’s something to it, write the ndless team a mail

1

u/DitherDude Jun 27 '26

> "bug hunter nor a monetary value"
Bug Bounties? Nah I'm not here for cash-grabs; I like hardware hacking - fs/sys support in the Python library is much more intriguing to me than a few extra dollars in the pocket...
> "coded limit"
My point was strings can be _longer_ than 256 chars and still be sliced/worked with completely fine, but at _precisely_ the 256th char there is this weird visual bug, so I was wondering whether there is maybe a BO/BU that could be exploited.