Re: [PATCH] ethernet: hisilicon: hns: hns_dsaf_misc: fix a possible array overflow in hns_dsaf_ge_srst_by_port()

[lipeng (Y)]

Sorry for the late reply.

Seeing this functions:

static int hns_mac_get_max_port_num(struct dsaf_device *dsaf_dev)
{
    if (HNS_DSAF_IS_DEBUG(dsaf_dev))
        return 1;
    else
        return  DSAF_MAX_PORT_NUM;
}

int hns_mac_init(struct dsaf_device *dsaf_dev)
{
    bool found = false;
    int ret;
    u32 port_id;
    int max_port_num = hns_mac_get_max_port_num(dsaf_dev);
    struct hns_mac_cb *mac_cb;
    struct fwnode_handle *child;

    device_for_each_child_node(dsaf_dev->dev, child) {
        ret = fwnode_property_read_u32(child, "reg", &port_id);
        if (ret) {
            dev_err(dsaf_dev->dev,
                "get reg fail, ret=%d!\n", ret);
            return ret;
        }
        if (port_id >= max_port_num) {
            dev_err(dsaf_dev->dev,
                "reg(%u) out of range!\n", port_id);
            return -EINVAL;
        }

The port_id had limit to DSAF_MAX_PORT_NUM, so this patch is 
unnecessary, thanks!


On 2021/11/17 11:44, Teng Qi wrote:
> The if statement:
>    if (port >= DSAF_GE_NUM)
>          return;
>
> limits the value of port less than DSAF_GE_NUM (i.e., 8).
> However, if the value of port is 6 or 7, an array overflow could occur:
>    port_rst_off = dsaf_dev->mac_cb[port]->port_rst_off;
>
> because the length of dsaf_dev->mac_cb is DSAF_MAX_PORT_NUM (i.e., 6).
>
> To fix this possible array overflow, we first check port and if it is
> greater than or equal to DSAF_MAX_PORT_NUM, the function returns.
>
> Reported-by: TOTE Robot <oslab@xxxxxxxxxxxxxxx>
> Signed-off-by: Teng Qi <starmiku1207184332@xxxxxxxxx>
> ---
>   drivers/net/ethernet/hisilicon/hns/hns_dsaf_misc.c | 4 ++++
>   1 file changed, 4 insertions(+)
>
> diff --git a/drivers/net/ethernet/hisilicon/hns/hns_dsaf_misc.c b/drivers/net/ethernet/hisilicon/hns/hns_dsaf_misc.c
> index 23d9cbf262c3..740850b64aff 100644
> --- a/drivers/net/ethernet/hisilicon/hns/hns_dsaf_misc.c
> +++ b/drivers/net/ethernet/hisilicon/hns/hns_dsaf_misc.c
> @@ -400,6 +400,10 @@ static void hns_dsaf_ge_srst_by_port(struct dsaf_device *dsaf_dev, u32 port,
>   		return;
>   
>   	if (!HNS_DSAF_IS_DEBUG(dsaf_dev)) {
> +		/* DSAF_MAX_PORT_NUM is 6, but DSAF_GE_NUM is 8.
> +		   We need check to prevent array overflow */
> +		if (port >= DSAF_MAX_PORT_NUM)
> +			return;
>   		reg_val_1  = 0x1 << port;
>   		port_rst_off = dsaf_dev->mac_cb[port]->port_rst_off;
>   		/* there is difference between V1 and V2 in register.*/