Subject: Re: [PATCH net-next] nfnetlink: do not ack malformed messages

From: Sergei Shtylyov <[email-masked]>
Date: Fri, 08 Nov 2013 02:03:20 +0300

Hello.

On 11/07/2013 09:59 PM, Jiri Benc wrote:

> Commit 0628b123c96d ("netfilter: nfnetlink: add batch support and use it
> from nf_tables") introduced a bug leading to various crashes in netlink_ack
> when netlink message with invalid nlmsg_len was sent by an unprivileged
> user.

> Signed-off-by: Jiri Benc <[email-masked]>
> ---
>   net/netfilter/nfnetlink.c |    8 +++++---
>   1 files changed, 5 insertions(+), 3 deletions(-)

> diff --git a/net/netfilter/nfnetlink.c b/net/netfilter/nfnetlink.c
> index 027f16a..046aa13 100644
> --- a/net/netfilter/nfnetlink.c
> +++ b/net/netfilter/nfnetlink.c
> @@ -363,13 +363,15 @@ static void nfnetlink_rcv(struct sk_buff *skb)
>   	struct net *net = sock_net(skb->sk);
>   	int msglen;
>
> -	if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
> -		return netlink_ack(skb, nlh, -EPERM);
> -

    Hm, how it even compiled before your patch?

WBR, Sergei