netdev - Re: [PATCH net-next] net: fix up truesize of cloned skb in skb_prepare_for

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:   Tue, 2 Feb 2021 19:34:48 +0100
From:   Marco Elver <elver@...gle.com>
To:     Eric Dumazet <edumazet@...gle.com>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        kasan-dev <kasan-dev@...glegroups.com>,
        David Miller <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Jonathan Lemon <jonathan.lemon@...il.com>,
        Willem de Bruijn <willemb@...gle.com>,
        linmiaohe <linmiaohe@...wei.com>,
        Guillaume Nault <gnault@...hat.com>,
        Dongseok Yi <dseok.yi@...sung.com>,
        Yadu Kishore <kyk.segfault@...il.com>,
        Al Viro <viro@...iv.linux.org.uk>,
        netdev <netdev@...r.kernel.org>,
        Alexander Potapenko <glider@...gle.com>,
        syzbot <syzbot+7b99aafdcc2eedea6178@...kaller.appspotmail.com>
Subject: Re: [PATCH net-next] net: fix up truesize of cloned skb in skb_prepare_for_shift()

On Tue, 2 Feb 2021 at 18:59, Eric Dumazet <edumazet@...gle.com> wrote:
>
> On Mon, Feb 1, 2021 at 5:04 PM Marco Elver <elver@...gle.com> wrote:
> >
> > Avoid the assumption that ksize(kmalloc(S)) == ksize(kmalloc(S)): when
> > cloning an skb, save and restore truesize after pskb_expand_head(). This
> > can occur if the allocator decides to service an allocation of the same
> > size differently (e.g. use a different size class, or pass the
> > allocation on to KFENCE).
> >
> > Because truesize is used for bookkeeping (such as sk_wmem_queued), a
> > modified truesize of a cloned skb may result in corrupt bookkeeping and
> > relevant warnings (such as in sk_stream_kill_queues()).
> >
> > Link: https://lkml.kernel.org/r/X9JR/J6dMMOy1obu@elver.google.com
> > Reported-by: syzbot+7b99aafdcc2eedea6178@...kaller.appspotmail.com
> > Suggested-by: Eric Dumazet <edumazet@...gle.com>
> > Signed-off-by: Marco Elver <elver@...gle.com>
>
> Signed-off-by: Eric Dumazet <edumazet@...gle.com>

Thank you!