Re: [PATCH] [BACKPORT v4.9 - v4.19] firmware: arm_scpi: Fix string overflow in SCPI genpd driver

[Greg KH]

On Fri, Dec 17, 2021 at 02:20:56PM +0000, Sudeep Holla wrote:
> commit 865ed67ab955428b9aa771d8b4f1e4fb7fd08945 upstream.
> 
> Without the bound checks for scpi_pd->name, it could result in the buffer
> overflow when copying the SCPI device name from the corresponding device
> tree node as the name string is set at maximum size of 30.
> 
> Let us fix it by using devm_kasprintf so that the string buffer is
> allocated dynamically.
> 
> Fixes: 8bec4337ad40 ("firmware: scpi: add device power domain support using genpd")
> Reported-by: Pedro Batista <pedbap.g@xxxxxxxxx>
> Signed-off-by: Sudeep Holla <sudeep.holla@xxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx #v4.9, v4.14, v4.19
> Cc: Cristian Marussi <cristian.marussi@xxxxxxx>
> Link: https://lore.kernel.org/r/20211209120456.696879-1-sudeep.holla@xxxxxxx
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
> ---
>  drivers/firmware/scpi_pm_domain.c | 10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/firmware/scpi_pm_domain.c b/drivers/firmware/scpi_pm_domain.c
> index f395dec27113..a6e62a793fbe 100644
> --- a/drivers/firmware/scpi_pm_domain.c
> +++ b/drivers/firmware/scpi_pm_domain.c
> @@ -27,7 +27,6 @@ struct scpi_pm_domain {
>  	struct generic_pm_domain genpd;
>  	struct scpi_ops *ops;
>  	u32 domain;
> -	char name[30];
>  };
>  
>  /*
> @@ -121,8 +120,13 @@ static int scpi_pm_domain_probe(struct platform_device *pdev)
>  
>  		scpi_pd->domain = i;
>  		scpi_pd->ops = scpi_ops;
> -		sprintf(scpi_pd->name, "%s.%d", np->name, i);
> -		scpi_pd->genpd.name = scpi_pd->name;
> +		scpi_pd->genpd.name = devm_kasprintf(dev, GFP_KERNEL,
> +						     "%s.%d", np->name, i);
> +		if (!scpi_pd->genpd.name) {
> +			dev_err(dev, "Failed to allocate genpd name:%s.%d\n",
> +				np->name, i);
> +			continue;
> +		}
>  		scpi_pd->genpd.power_off = scpi_pd_power_off;
>  		scpi_pd->genpd.power_on = scpi_pd_power_on;
>  
> -- 
> 2.25.1
> 

Now queued up, thanks.

greg k-h