Re: [PATCH RFC v2 0/6] staging: r8188eu: avoid uninit value bugs

Pavel Skripkin
2021-08-22T15:30:12Z

On 8/22/21 5:35 PM, Pavel Skripkin wrote:
> Hi, Greg, Larry and Phillip!
>
> I noticed, that new staging driver was added like 3 weeks ago and I decided
> to look at the code, because drivers in staging directory are always buggy.
>
> The first thing I noticed is *no one* was checking read operations result, but
> it can fail and driver may start writing random stack values into registers. It
> can cause driver misbehavior or device misbehavior.
>
> To avoid this type of bugs, i've changed rtw_read* API. Now all rtw_read
> funtions return an error, when something went wrong with usb transfer.
>
> It helps callers to break/return earlier and don't write random values to
> registers or to rely on random values.
>
> Why is this pacth series RFC?
> 1. I don't have this device and I cannot test these changes.
> 2. I don't know how to handle errors in each particular case. For now, function
> just returns or returns an error. That's all. I hope, driver maintainers will
> help with these bits.
> 3. I guess, I handled not all uninit value bugs here. I hope, I fixed
> at least half of them
>
>
> v1 -> v2:
> 1. Make rtw_read*() return an error instead of initializing pointer to error
> 2. Split one huge patch to smaller ones for each rtw_read{8,16,32} function
> changes
> 3. Add new macro for printing register values (It helps to not copy-paste error
> handling)
> 4. Removed {read,write}_macreg (Suggested by Phillip)
> 5. Rebased on top of staging-next
> 6. Cleaned checkpatch errors and warnings
>
> Only build-tested, since I don't have device with r8118eu chip
>

BTW, can you recommend any devices with this chip except for ASUS
USB-N10 Nano? I didn't find any of them with delivery/reasonable
delivery price to Russia.

I want to help with testing and moving this driver out of staging
directory :)

With regards,
Pavel Skripkin