netdev - Re: [PATCH net] net_sched: ematch: reject invalid TCF_EM

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Date:   Fri, 24 Jan 2020 16:43:23 -0800
From:   Cong Wang <xiyou.wangcong@...il.com>
To:     Eric Dumazet <edumazet@...gle.com>
Cc:     "David S . Miller" <davem@...emloft.net>,
        netdev <netdev@...r.kernel.org>,
        Eric Dumazet <eric.dumazet@...il.com>,
        syzbot+03c4738ed29d5d366ddf@...kaller.appspotmail.com
Subject: Re: [PATCH net] net_sched: ematch: reject invalid TCF_EM_SIMPLE

On Fri, Jan 24, 2020 at 2:57 PM Eric Dumazet <edumazet@...gle.com> wrote:
>
> It is possible for malicious userspace to set TCF_EM_SIMPLE bit
> even for matches that should not have this bit set.
>
> This can fool two places using tcf_em_is_simple()
>
> 1) tcf_em_tree_destroy() -> memory leak of em->data
>    if ops->destroy() is NULL
>
> 2) tcf_em_tree_dump() wrongly report/leak 4 low-order bytes
>    of a kernel pointer.

Acked-by: Cong Wang <xiyou.wangcong@...il.com>