Re: [PATCH 7/8] scsi: core: Use scnprintf() for avoiding potential buffer overflow

[John Garry <john.garry@xxxxxxxxxx>]

On 11/03/2020 09:16, Takashi Iwai wrote:
> Since snprintf() returns the would-be-output size instead of the
> actual output size, the succeeding calls may go beyond the given
> buffer limit.  Fix it by replacing with scnprintf().
>
> Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
> ---
>   drivers/scsi/scsi_sysfs.c | 6 +++---
>   1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
> index c3a30ba4ae08..6b3644246d3a 100644
> --- a/drivers/scsi/scsi_sysfs.c
> +++ b/drivers/scsi/scsi_sysfs.c
> @@ -1045,14 +1045,14 @@ sdev_show_blacklist(struct device *dev, struct device_attribute *attr,
>   			name = sdev_bflags_name[i];
>   
>   		if (name)
> -			len += snprintf(buf + len, PAGE_SIZE - len,
> +			len += scnprintf(buf + len, PAGE_SIZE - len,
>   					"%s%s", len ? " " : "", name);

It would be nice to ensure that alignment with the parenthesis is maintained

Thanks

>   		else
> -			len += snprintf(buf + len, PAGE_SIZE - len,
> +			len += scnprintf(buf + len, PAGE_SIZE - len,
>   					"%sINVALID_BIT(%d)", len ? " " : "", i);
>   	}
>   	if (len)
> -		len += snprintf(buf + len, PAGE_SIZE - len, "\n");
> +		len += scnprintf(buf + len, PAGE_SIZE - len, "\n");
>   	return len;
>   }
>   static DEVICE_ATTR(blacklist, S_IRUGO, sdev_show_blacklist, NULL);