netdev - Re: [PATCH net v2] rtnetlink: Disallow FDB configuration for non-Ethernet device

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Date:   Mon, 29 Oct 2018 14:39:24 -0600
From:   David Ahern <dsahern@...il.com>
To:     Ido Schimmel <idosch@...lanox.com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Cc:     "davem@...emloft.net" <davem@...emloft.net>,
        Vlad Yasevich <vyasevich@...il.com>
Subject: Re: [PATCH net v2] rtnetlink: Disallow FDB configuration for
 non-Ethernet device

On 10/29/18 2:36 PM, Ido Schimmel wrote:
> When an FDB entry is configured, the address is validated to have the
> length of an Ethernet address, but the device for which the address is
> configured can be of any type.
> 
> The above can result in the use of uninitialized memory when the address
> is later compared against existing addresses since 'dev->addr_len' is
> used and it may be greater than ETH_ALEN, as with ip6tnl devices.
> 
> Fix this by making sure that FDB entries are only configured for
> Ethernet devices.

...

> 
> Fixes: 090096bf3db1 ("net: generic fdb support for drivers without ndo_fdb_<op>")
> Signed-off-by: Ido Schimmel <idosch@...lanox.com>
> Reported-and-tested-by: syzbot+3a288d5f5530b901310e@...kaller.appspotmail.com
> Reported-and-tested-by: syzbot+d53ab4e92a1db04110ff@...kaller.appspotmail.com
> Cc: Vlad Yasevich <vyasevich@...il.com>
> Cc: David Ahern <dsahern@...il.com>
> ---
>  net/core/rtnetlink.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)

Reviewed-by: David Ahern <dsahern@...il.com>