netdev - Re: [RFC 1/3] tc: fix return values of ingress qdisc

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, 22 Apr 2015 15:04:03 -0700
From:	Alexei Starovoitov <ast@...mgrid.com>
To:	Cong Wang <cwang@...pensource.com>
CC:	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jamal Hadi Salim <jhs@...atatu.com>,
	John Fastabend <john.r.fastabend@...el.com>,
	netdev <netdev@...r.kernel.org>
Subject: Re: [RFC 1/3] tc: fix return values of ingress qdisc

On 4/21/15 9:59 PM, Cong Wang wrote:
> On Tue, Apr 21, 2015 at 12:27 PM, Alexei Starovoitov <ast@...mgrid.com> wrote:
>> ingress qdisc should return NET_XMIT_* values just like all other qdiscs.
>>
>
> XMIT already means egress...

may be then it should be renamed as well.
from include/linux/netdevice.h:
/* qdisc ->enqueue() return codes. */
#define NET_XMIT_SUCCESS        0x00
...

the point is that qdisc->enqeue() must return NET_XMIT_* values.
ingress qdisc is violating this and therefore should be fixed.

>> Since it's invoked via qdisc_enqueue_root() (which suppose to return
>> only NET_XMIT_* values as well), it was working by accident,
>> since TC_ACT_* values fit within NET_XMIT_MASK.
>>
>
> Why not just add a BUILD_BUG_ON() to capture this?

ingress qdisc returning TC_ACT_* values is an obvious layering
violation. I'm puzzled why it's been this way for so long.
Adding BUILD_BUG_ON is not an option.
--
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