Re: [PATCH v7 07/15] scsi: fnic: Add and integrate support for FDMI

[Dan Carpenter <dan.carpenter@linaro.org>]

On Wed, Dec 11, 2024 at 06:03:04PM -0800, Karan Tilak Kumar wrote:
> @@ -612,6 +615,7 @@ static int fnic_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
>  	unsigned long flags;
>  	int hwq;
>  	char *desc, *subsys_desc;
> +	int len;

Do not introduce unnecessary levels of indirection.  Get rid of this len
variable.

>  
>  	/*
>  	 * Allocate SCSI Host and set up association between host,
> @@ -646,9 +650,17 @@ static int fnic_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
>  	fnic_stats_debugfs_init(fnic);
>  
>  	/* Find model name from PCIe subsys ID */
> -	if (fnic_get_desc_by_devid(pdev, &desc, &subsys_desc) == 0)
> +	if (fnic_get_desc_by_devid(pdev, &desc, &subsys_desc) == 0) {
>  		dev_info(&fnic->pdev->dev, "Model: %s\n", subsys_desc);
> -	else {
> +
> +		/* Update FDMI model */

This comment adds no information.  Delete it.

> +		fnic->subsys_desc_len = strlen(subsys_desc);

Keep in mind that strlen() does not count the NUL-terminator.

> +		len = ARRAY_SIZE(fnic->subsys_desc);

Use sizeof() when you are talking about bytes or chars.  For snprintf() and
other string functions, it's always sizeof() and never ARRAY_SIZE().

> +		if (fnic->subsys_desc_len > len)
> +			fnic->subsys_desc_len = len;
> +		memcpy(fnic->subsys_desc, subsys_desc, fnic->subsys_desc_len);

So this is an 0-14 character buffer.  If fnic->subsys_desc_len is set to 14,
then the string is not NUL terminated.  This is how the buffer is used in
fdls_fdmi_register_hba()

	strscpy_pad(data, fnic->subsys_desc, FNIC_FDMI_MODEL_LEN);
	data[FNIC_FDMI_MODEL_LEN - 1] = 0;

This suggests that fnic->subsys_desc is expected to be NUL-terminated.
However FNIC_FDMI_MODEL_LEN is 12.  So in that case the last 3 characters
are removed.  LOL.  It's harmless but so very annoying.

Also strscpy_pad() will ensure that data[FNIC_FDMI_MODEL_LEN - 1] is set
to zero so that line could be deleted.

regards,
dan carpenter