> From: Dan Carpenter [mailto:dan.carpen...@oracle.com]
> Sent: Friday, March 17, 2017 1:53 PM
>
> We could allocate less memory than intended because we do:
>
> bnad->regdata = kzalloc(len << 2, GFP_KERNEL);
>
> The shift can overflow leading to a crash. This is debugfs code so the impact
> is very small.
>
> Fixes: 7afc5dbde091 ("bna: Add debugfs interface.")
> Signed-off-by: Dan Carpenter
>
> diff --git a/drivers/net/ethernet/brocade/bna/bnad_debugfs.c
> b/drivers/net/ethernet/brocade/bna/bnad_debugfs.c
> index 05c1c1dd7751..cebfe3bd086e 100644
> --- a/drivers/net/ethernet/brocade/bna/bnad_debugfs.c
> +++ b/drivers/net/ethernet/brocade/bna/bnad_debugfs.c
> @@ -325,7 +325,7 @@ bnad_debugfs_write_regrd(struct file *file, const
> char __user *buf,
> return PTR_ERR(kern_buf);
>
> rc = sscanf(kern_buf, "%x:%x", &addr, &len);
> - if (rc < 2) {
> + if (rc < 2 || len > UINT_MAX >> 2) {
> netdev_warn(bnad->netdev, "failed to read user buffer\n");
> kfree(kern_buf);
> return -EINVAL;
You are correct, thanks Dan for adding the check.
Acked-by: Rasesh Mody