Re: [PATCH v2] core: dev: don't call BUG() on bad input

From: Alexey Dobriyan <adobriyan@gmail.com>
To: Vasiliy Kulikov <segoon@openwall.com>
Cc: linux-kernel@vger.kernel.org,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <eric.dumazet@gmail.com>,
	Tom Herbert <therbert@google.com>,
	Changli Gao <xiaosuo@gmail.com>, Jesse Gross <jesse@nicira.com>,
	netdev@vger.kernel.org
Subject: Re: [PATCH v2] core: dev: don't call BUG() on bad input
Date: Mon, 14 Feb 2011 17:16:00 +0200	[thread overview]
Message-ID: <AANLkTimidxVJxw-XKTWwCZh8k_vKHDeqxAwVbY6+aJ6x@mail.gmail.com> (raw)
In-Reply-To: <1297694579-23611-1-git-send-email-segoon@openwall.com>

On Mon, Feb 14, 2011 at 4:42 PM, Vasiliy Kulikov <segoon@openwall.com> wrote:
> alloc_netdev() may be called with too long name (more that IFNAMSIZ bytes).
> Currently this leads to BUG().  Other insane inputs (bad txqs, rxqs) and
> even OOM don't lead to BUG().  Made alloc_netdev() return NULL, like on
> other errors.

> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -5761,7 +5761,10 @@ struct net_device *alloc_netdev_mqs(int sizeof_priv, const char *name,
>        size_t alloc_size;
>        struct net_device *p;
>
> -       BUG_ON(strlen(name) >= sizeof(dev->name));
> +       if (strnlen(name, sizeof(dev->name)) >= sizeof(dev->name)) {
> +               pr_err("alloc_netdev: Too long device name\n");
> +               return NULL;
> +       }

Netdevice name isn't some random junk you get from userspace, so BUG is fine.