Re: [PATCH RFC 0/3] staging: r8188eu: avoid uninit value bugs

Phillip Potter
2021-08-20T23:12:53Z

On Fri, 2021-08-20 at 20:07 +0300, 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 expanded read() API with error
> parametr,
> which will be initialized to error if read fails. 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
>
> This series was build-tested and made on top of staging-testing
> branch
>
>
> With regards,
> Pavel Skripkin
>
> Pavel Skripkin (3):
>   staging: r8188eu: add proper rtw_read* error handling
>   staging: r8188eu: add error handling to ReadFuse
>   staging: r8188eu: add error argument to read_macreg
>
>  drivers/staging/r8188eu/core/rtw_debug.c      |  79 +++-
>  drivers/staging/r8188eu/core/rtw_efuse.c      | 119 +++--
>  drivers/staging/r8188eu/core/rtw_io.c         |  18 +-
>  drivers/staging/r8188eu/core/rtw_mp.c         |  38 +-
>  drivers/staging/r8188eu/core/rtw_mp_ioctl.c   |  20 +-
>  drivers/staging/r8188eu/core/rtw_pwrctrl.c    |   6 +-
>  drivers/staging/r8188eu/core/rtw_sreset.c     |   7 +-
>  drivers/staging/r8188eu/hal/HalPwrSeqCmd.c    |   9 +-
>  drivers/staging/r8188eu/hal/hal_com.c         |  22 +-
>  drivers/staging/r8188eu/hal/hal_intf.c        |   6 +-
>  drivers/staging/r8188eu/hal/odm_interface.c   |  12 +-
>  drivers/staging/r8188eu/hal/rtl8188e_cmd.c    |  37 +-
>  drivers/staging/r8188eu/hal/rtl8188e_dm.c     |   6 +-
>  .../staging/r8188eu/hal/rtl8188e_hal_init.c   | 260 ++++++++---
>  drivers/staging/r8188eu/hal/rtl8188e_phycfg.c |  26 +-
>  drivers/staging/r8188eu/hal/rtl8188e_sreset.c |  20 +-
>  drivers/staging/r8188eu/hal/rtl8188eu_led.c   |  17 +-
>  drivers/staging/r8188eu/hal/usb_halinit.c     | 412 ++++++++++++++--
> --
>  drivers/staging/r8188eu/hal/usb_ops_linux.c   |  55 ++-
>  drivers/staging/r8188eu/include/hal_intf.h    |   6 +-
>  .../staging/r8188eu/include/rtl8188e_hal.h    |   2 +-
>  drivers/staging/r8188eu/include/rtw_efuse.h   |   4 +-
>  drivers/staging/r8188eu/include/rtw_io.h      |  18 +-
>  drivers/staging/r8188eu/include/rtw_mp.h      |   2 +-
>  drivers/staging/r8188eu/os_dep/ioctl_linux.c  | 168 +++++--
>  drivers/staging/r8188eu/os_dep/usb_intf.c     |   4 +-
>  26 files changed, 1072 insertions(+), 301 deletions(-)
>

Dear Pavel,

Firstly, thank you for this contribution, it is much appreciated.
Whilst I'm still learning myself when it comes to this driver and to
kernel code in general, I can certainly say the code looks pretty good
in general so far. I will try and offer individual comments on each
patch.

Regards,
Phil