Re: [PATCH 1/4] media: venus: hfi_parser: add check to avoid out of bound access

[Bryan O'Donoghue <bryan.odonoghue@linaro.org>]

On 07/11/2024 13:54, Dmitry Baryshkov wrote:
>>> I'd say, don't overwrite the array. Instead the driver should extend it
>>> with the new information.
>> That is exactly the existing patch is currently doing.
> _new_ information, not a copy of the existing information.

But is this _really_ new information or is it guarding from "malicious" 
additional messages ?

@Vikash is it even a valid use-case for firmware to send one set of 
capabilities and then send a new set ?

It seems to me this should only happen once when the firmware starts up 
- the firmware won't acquire any new abilities once it has enumerated 
its set to APSS.

So why is it valid to process an additional message at all ?

Shouldn't we instead be throwing away redundant updates either silently 
or with some kind of complaint ?

If there's no new data - then this is data we shouldn't bother processing.

If it is new data then surely it should be the _current_ and _only_ 
valid set of data.

And if the update is considered "invalid" then why _would_ we accept the 
update ?

I get we're fixing the OOB but I think we should be clear on the 
validity of the content of the packet.

---
bod