Subject: Re: [PATCH net] bna: adjust 'name' buf size of bna_tcb and bna_ccb structures

From: Simon Horman <[email-masked]>
Date: Thu, 27 Jun 2024 15:17:55 +0100

+ Eric Dumazet, Jakub Kicinski, Paolo Abeni

On Tue, Jun 25, 2024 at 07:14:33PM +0000, Alexey Kodanev wrote:
> To have enough space to write all possible sprintf() args. Currently
> 'name' size is 16, but the first '%s' specifier may already need at
> least 16 characters, since 'bnad->netdev->name' is used there.
> 
> For '%d' specifiers, assume that they require:
>  * 1 char for 'tx_id + tx_info->tcb[i]->id' sum, BNAD_MAX_TXQ_PER_TX is 8
>  * 2 chars for 'rx_id + rx_info->rx_ctrl[i].ccb->id', BNAD_MAX_RXP_PER_RX
>    is 16
> 
> And replace sprintf with snprintf.
> 
> Detected using the static analysis tool - Svace.
> 
> Fixes: 8b230ed8ec96 ("bna: Brocade 10Gb Ethernet device driver")
> Signed-off-by: Alexey Kodanev <[email-masked]>

Thanks Alexey,

I agree that this change is a nice improvement.  And I verified that gcc-13
W=1 builds on x86_64 report warnings regarding the issues addressed by this
patch: the warnings are resolved by this patch.

But I do also wonder if we should consider removing this driver.
I don't see any non-trivial updates to it since
commit d667f78514c6 ("bna: Add synchronization for tx ring.")
a bug fix from November 2016 which was included in v4.9.

Although, perhaps your patch indicates this driver is being used :)

On process:

When posting patches for net or net-next, please generate a CC list using
./scripts/get_maintainer.pl your.patch

This does not seem to be a bug fix in the sense that it doesn't seem
to resolve a problem that manifests itself. If so, it should be targeted
at net-next rather than net.

Link: https://docs.kernel.org/process/maintainer-netdev.html

...

> ---
>  drivers/net/ethernet/brocade/bna/bna_types.h |  2 +-
>  drivers/net/ethernet/brocade/bna/bnad.c      | 11 ++++++-----
>  2 files changed, 7 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/net/ethernet/brocade/bna/bna_types.h b/drivers/net/ethernet/brocade/bna/bna_types.h
> index a5ebd7110e07..986f43d27711 100644
> --- a/drivers/net/ethernet/brocade/bna/bna_types.h
> +++ b/drivers/net/ethernet/brocade/bna/bna_types.h
> @@ -416,7 +416,7 @@ struct bna_ib {
>  /* Tx object */
>  
>  /* Tx datapath control structure */
> -#define BNA_Q_NAME_SIZE		16
> +#define BNA_Q_NAME_SIZE		(IFNAMSIZ + 6)
>  struct bna_tcb {
>  	/* Fast path */
>  	void			**sw_qpt;
> diff --git a/drivers/net/ethernet/brocade/bna/bnad.c b/drivers/net/ethernet/brocade/bna/bnad.c
> index fe121d36112d..3313a0d84466 100644
> --- a/drivers/net/ethernet/brocade/bna/bnad.c
> +++ b/drivers/net/ethernet/brocade/bna/bnad.c
> @@ -1534,8 +1534,9 @@ bnad_tx_msix_register(struct bnad *bnad, struct bnad_tx_info *tx_info,
>  
>  	for (i = 0; i < num_txqs; i++) {
>  		vector_num = tx_info->tcb[i]->intr_vector;
> -		sprintf(tx_info->tcb[i]->name, "%s TXQ %d", bnad->netdev->name,
> -				tx_id + tx_info->tcb[i]->id);
> +		snprintf(tx_info->tcb[i]->name, BNA_Q_NAME_SIZE, "%s TXQ %d",
> +			 bnad->netdev->name,
> +			 tx_id + tx_info->tcb[i]->id);
>  		err = request_irq(bnad->msix_table[vector_num].vector,
>  				  (irq_handler_t)bnad_msix_tx, 0,
>  				  tx_info->tcb[i]->name,
> @@ -1585,9 +1586,9 @@ bnad_rx_msix_register(struct bnad *bnad, struct bnad_rx_info *rx_info,
>  
>  	for (i = 0; i < num_rxps; i++) {
>  		vector_num = rx_info->rx_ctrl[i].ccb->intr_vector;
> -		sprintf(rx_info->rx_ctrl[i].ccb->name, "%s CQ %d",
> -			bnad->netdev->name,
> -			rx_id + rx_info->rx_ctrl[i].ccb->id);
> +		snprintf(rx_info->rx_ctrl[i].ccb->name, BNA_Q_NAME_SIZE, "%s CQ %d",

nit: This line could be trivially line wrapped so that it is less than 80
     columns wide, which is still preferred for Networking code.

     Flagged by /scripts/checkpatch.pl --max-line-length=80

> +			 bnad->netdev->name,
> +			 rx_id + rx_info->rx_ctrl[i].ccb->id);
>  		err = request_irq(bnad->msix_table[vector_num].vector,
>  				  (irq_handler_t)bnad_msix_rx, 0,
>  				  rx_info->rx_ctrl[i].ccb->name,
> -- 
> 2.25.1
> 
>