netdev - Re: Why do we prefer skb->priority to tc filters?

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Wed, 11 Mar 2015 13:09:42 -0700
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Cong Wang <cwang@...pensource.com>
Cc:	netdev <netdev@...r.kernel.org>,
	Jamal Hadi Salim <jhs@...atatu.com>,
	David Miller <davem@...emloft.net>
Subject: Re: Why do we prefer skb->priority to tc filters?

On Wed, 2015-03-11 at 12:18 -0700, Cong Wang wrote:
> This is exactly why I am asking, kernel respects user's choice so much
> that it could override even both cgroup prio and tc filters, I don't know
> what is the reason behind, but this means our tc filters can not work
> with an application which sets skb->priority. For example, our tc filters
> classify the packets from this socket into flow 1:1, but application
> sets 1:2 by itself...

Application cannot set whatever skb->priority, unless it really knows
better than kernel.

        case SO_PRIORITY:
                if ((val >= 0 && val <= 6) ||
                    ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
                        sk->sk_priority = val;
                else
                        ret = -EPERM;
                break;



--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html