From: David Miller <davem@davemloft.net>
To: vdronov@redhat.com
Cc: kuznet@ms2.inr.ac.ru, yoshfuji@linux-ipv6.org,
netdev@vger.kernel.org, syzkaller@googlegroups.com,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] net: arp, ipv6: handle special case of tap device
Date: Sat, 29 Sep 2018 11:40:23 -0700 (PDT) [thread overview]
Message-ID: <20180929.114023.1370133506922372520.davem@davemloft.net> (raw)
In-Reply-To: <20180926093018.6646-1-vdronov@redhat.com>
From: Vladis Dronov <vdronov@redhat.com>
Date: Wed, 26 Sep 2018 11:30:18 +0200
> @@ -187,7 +187,14 @@ EXPORT_SYMBOL(arp_tbl);
>
> int arp_mc_map(__be32 addr, u8 *haddr, struct net_device *dev, int dir)
> {
> - switch (dev->type) {
> + unsigned short type = dev->type;
> +
> +#if IS_ENABLED(CONFIG_TAP)
> + if (dev->rtnl_link_ops && !strcmp(dev->rtnl_link_ops->kind, "tun"))
> + type = ARPHRD_ETHER;
> +#endif /* CONFIG_TAP */
This is insanely ugly.
dev->type determines the link layer header layout and size.
You can fix the kernel, but userspace AF_PACKET applications are still
going to be broken by this behavior. And that is just the tip of the
iceberg.
I'm not applying this, sorry. I think tun/tap should be prevented from
allowing the dev->type to be changed, unless it will make those changes
adjust the link layer headers properly as well.
Sorry.
next prev parent reply other threads:[~2018-09-29 18:40 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-26 9:30 [PATCH] net: arp, ipv6: handle special case of tap device Vladis Dronov
2018-09-29 18:40 ` David Miller [this message]
2018-10-01 11:32 ` Vladis Dronov
2018-10-03 5:25 ` David Miller
2018-10-03 13:25 ` Vladis Dronov
2018-10-03 16:37 ` David Miller
2018-10-04 9:53 ` Kalle Valo
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