netdev - Re: [Patch net 00/16] net_sched: fix races with RCU callbacks

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:   Sun, 29 Oct 2017 23:41:57 +0900 (KST)
From:   David Miller <davem@...emloft.net>
To:     xiyou.wangcong@...il.com
Cc:     netdev@...r.kernel.org, chrism@...lanox.com, daniel@...earbox.net,
        jiri@...nulli.us, john.fastabend@...il.com, jhs@...atatu.com,
        paulmck@...ux.vnet.ibm.com
Subject: Re: [Patch net 00/16] net_sched: fix races with RCU callbacks

From: Cong Wang <xiyou.wangcong@...il.com>
Date: Thu, 26 Oct 2017 18:24:27 -0700

> Recently, the RCU callbacks used in TC filters and TC actions keep
> drawing my attention, they introduce at least 4 race condition bugs:
 ...
> As suggested by Paul, we could defer the work to a workqueue and
> gain the permission of holding RTNL again without any performance
> impact, however, in tcf_block_put() we could have a deadlock when
> flushing workqueue while hodling RTNL lock, the trick here is to
> defer the work itself in workqueue and make it queued after all
> other works so that we keep the same ordering to avoid any
> use-after-free. Please see the first patch for details.
> 
> Patch 1 introduces the infrastructure, patch 2~12 move each
> tc filter to the new tc filter workqueue, patch 13 adds
> an assertion to catch potential bugs like this, patch 14
> closes another rcu callback race, patch 15 and patch 16 add
> new test cases.

I know Eric has some reservations about how things have become in
this layer, but we have to fix this for 'net' somehow.

So I've applied this series, thanks.