Re: [PATCH v2] nfc: fdp: add null check of devm_kmalloc_array in fdp_nci_i2c_read_device_properties

[Krzysztof Kozlowski]

On 27/02/2023 02:41, Kang Chen wrote:
> devm_kmalloc_array may fails, *fw_vsc_cfg might be null and cause
> out-of-bounds write in device_property_read_u8_array later.
> 
> Fixes: a06347c04c13 ("NFC: Add Intel Fields Peak NFC solution driver")
> 
No blank lines between tags.

> Signed-off-by: Kang Chen <void0red@xxxxxxxxx>
> ---
> v2 -> v1: add debug prompt and Fixes tag
> 
>  drivers/nfc/fdp/i2c.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/nfc/fdp/i2c.c b/drivers/nfc/fdp/i2c.c
> index 2d53e0f88..d3272a54b 100644
> --- a/drivers/nfc/fdp/i2c.c
> +++ b/drivers/nfc/fdp/i2c.c
> @@ -247,6 +247,11 @@ static void fdp_nci_i2c_read_device_properties(struct device *dev,
>  					   len, sizeof(**fw_vsc_cfg),
>  					   GFP_KERNEL);
>  
> +		if (!*fw_vsc_cfg) {
> +			dev_dbg(dev, "Not enough memory\n");

No prints for memory allocation errors. Core prints it. Just go to
err_kmalloc.

> +			goto out;
> +		}
> +
>  		r = device_property_read_u8_array(dev, FDP_DP_FW_VSC_CFG_NAME,
>  						  *fw_vsc_cfg, len);
>  
> @@ -259,7 +264,7 @@ static void fdp_nci_i2c_read_device_properties(struct device *dev,
>  		dev_dbg(dev, "FW vendor specific commands not present\n");
>  		*fw_vsc_cfg = NULL;
>  	}
> -

Why? Line break seems nice here.

> +out:
>  	dev_dbg(dev, "Clock type: %d, clock frequency: %d, VSC: %s",
>  		*clock_type, *clock_freq, *fw_vsc_cfg != NULL ? "yes" : "no");
>  }

Best regards,
Krzysztof