netdev - Re: [PATCH net 1/2] net/sched: cls_u32: fix netns refcount changes in u32

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]

Message-ID: <60ef60b7-f562-917a-ebd8-1d7cf7080d82@mojatatu.com>
Date:   Thu, 14 Apr 2022 11:59:01 -0400
From:   Jamal Hadi Salim <jhs@...atatu.com>
To:     Eric Dumazet <eric.dumazet@...il.com>,
        "David S . Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>
Cc:     Cong Wang <xiyou.wangcong@...il.com>,
        Jiri Pirko <jiri@...nulli.us>, netdev <netdev@...r.kernel.org>,
        Eric Dumazet <edumazet@...gle.com>,
        syzbot <syzkaller@...glegroups.com>
Subject: Re: [PATCH net 1/2] net/sched: cls_u32: fix netns refcount changes in
 u32_change()

On 2022-04-13 13:35, Eric Dumazet wrote:
> From: Eric Dumazet <edumazet@...gle.com>
> 
> We are now able to detect extra put_net() at the moment
> they happen, instead of much later in correct code paths.
> 
> u32_init_knode() / tcf_exts_init() populates the ->exts.net
> pointer, but as mentioned in tcf_exts_init(),
> the refcount on netns has not been elevated yet.
> 
> The refcount is taken only once tcf_exts_get_net()
> is called.
> 
> So the two u32_destroy_key() calls from u32_change()
> are attempting to release an invalid reference on the netns.
> 

Looks good to me.

Acked-by: Jamal Hadi Salim <jhs@...atatu.com>

cheers,
jamal