Re: [PATCH v2] sound: fix uninit-value in sof_ipc4_pcm_dai_link_fixup_rate

[Péter Ujfalusi <peter.ujfalusi@xxxxxxxxxxxxxxx>]

On 03/11/2024 13:37, Suraj Sonawane wrote:
> Fix an issue detected by the Smatch tool:
> 
> sound/soc/sof/ipc4-pcm.c: sof_ipc4_pcm_dai_link_fixup_rate()
> error: uninitialized symbol 'be_rate'.
> 
> This issue occurred because the variable 'be_rate' could remain
> uninitialized if num_input_formats is zero. In such cases, the
> loop that assigns a value to 'be_rate' would not execute,
> potentially leading to undefined behavior when rate->min and
> rate->max are set with an uninitialized 'be_rate'.
> 
> To resolve this, an additional check for num_input_formats > 0
> was added before setting rate->min and rate->max with 'be_rate'.
> This ensures that 'be_rate' is assigned only when there are valid
> input formats, preventing any use of uninitialized data.
> 
> This solution maintains defined behavior for rate->min and rate->max,
> ensuring they are only assigned when valid be_rate data is available.
> 
> Signed-off-by: Suraj Sonawane <surajsonawane0215@xxxxxxxxx>
> ---
> V1: Initialize 'be_rate' to 0.
> V2: Add conditional assignment based on num_input_formats to ensure
> be_rate is used only when assigned.
> 
>  sound/soc/sof/ipc4-pcm.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/sound/soc/sof/ipc4-pcm.c b/sound/soc/sof/ipc4-pcm.c
> index 4df2be3d3..d5d7ffc69 100644
> --- a/sound/soc/sof/ipc4-pcm.c
> +++ b/sound/soc/sof/ipc4-pcm.c
> @@ -633,8 +633,11 @@ static int sof_ipc4_pcm_dai_link_fixup_rate(struct snd_sof_dev *sdev,
>  			return -EINVAL;
>  		}
>  
> -		rate->min = be_rate;
> -		rate->max = rate->min;
> +		/* Set rate only if be_rate was assigned */
> +		if (num_input_formats > 0) {

By definition the copier must have at least one input and one output
format, this check is going to be always true.

> +			rate->min = be_rate;
> +			rate->max = rate->min;
> +		}
>  	}
>  
>  	return 0;

-- 
Péter