linux-kernel - Re: [PATCH] Input: hideep - fix the uninitialized use in hideep_nvm

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Date:   Sat, 19 Jun 2021 22:10:37 -0700
From:   Dmitry Torokhov <dmitry.torokhov@...il.com>
To:     Yizhuo Zhai <yzhai003@....edu>,
        Anthony Kim <anthony.kim@...eep.com>
Cc:     linux-input@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Input: hideep - fix the uninitialized use in
 hideep_nvm_unlock()

On Wed, Jun 16, 2021 at 03:48:51PM -0700, Yizhuo Zhai wrote:
> Inside function hideep_nvm_unlock(), variable "unmask_code" could
> be uninitialized if hideep_pgm_r_reg() returns error, however, it
> is used in the later if statement after an "and" operation, which
> is potentially unsafe.

I think this is pretty sensible, but let's see if the original author
has some comments...

> 
> Signed-off-by: Yizhuo <yzhai003@....edu>
> ---
>  drivers/input/touchscreen/hideep.c | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/input/touchscreen/hideep.c
> b/drivers/input/touchscreen/hideep.c
> index ddad4a82a5e5..f860a815b603 100644
> --- a/drivers/input/touchscreen/hideep.c
> +++ b/drivers/input/touchscreen/hideep.c
> @@ -364,9 +364,13 @@ static int hideep_enter_pgm(struct hideep_ts *ts)
>  static void hideep_nvm_unlock(struct hideep_ts *ts)
>  {
>         u32 unmask_code;
> +       int ret;
> 
>         hideep_pgm_w_reg(ts, HIDEEP_FLASH_CFG, HIDEEP_NVM_SFR_RPAGE);
> -       hideep_pgm_r_reg(ts, 0x0000000C, &unmask_code);
> +       ret = hideep_pgm_r_reg(ts, 0x0000000C, &unmask_code);
> +       if (ret)
> +               return ret;
> +
>         hideep_pgm_w_reg(ts, HIDEEP_FLASH_CFG, HIDEEP_NVM_DEFAULT_PAGE);
> 
>         /* make it unprotected code */
> @@ -462,7 +466,9 @@ static int hideep_program_nvm(struct hideep_ts *ts,
>         u32 addr = 0;
>         int error;
> 
> -       hideep_nvm_unlock(ts);
> +       error = hideep_nvm_unlock(ts);
> +       if (error)
> +               return error;
> 
>         while (ucode_len > 0) {
>                 xfer_len = min_t(size_t, ucode_len, HIDEEP_NVM_PAGE_SIZE);
> -- 
> 2.17.1

-- 
Dmitry