netdev - Re: KASAN poisoning for skb linear data

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: <CACT4Y+aLOqSqdfRYEyQB33MSXXb-3=APs5B1ZHsXJ2XYXF_Ppw@mail.gmail.com>
Date:   Thu, 8 Mar 2018 10:20:44 +0100
From:   Dmitry Vyukov <dvyukov@...gle.com>
To:     David Miller <davem@...emloft.net>,
        Willem de Bruijn <willemb@...gle.com>,
        Eric Dumazet <edumazet@...gle.com>,
        netdev <netdev@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        kasan-dev <kasan-dev@...glegroups.com>,
        Cong Wang <xiyou.wangcong@...il.com>,
        andreyknvl <andreyknvl@...gle.com>
Subject: Re: KASAN poisoning for skb linear data

On Mon, Jan 15, 2018 at 3:15 PM, Dmitry Vyukov <dvyukov@...gle.com> wrote:
> Hi,
>
> As far as I understand pskb_may_pull() plays important role in packet
> parsing for all protocols. And we did custom fragmentation of packets
> emitted via tun (IFF_NAPI_FRAGS). However, it seems that it does not
> give any results (bugs found), and I think the reason for this is that
> linear data is rounded up and is usually quite large. So if a parsing
> function does pskb_may_pull(1), or does not do it at all, it can
> usually access more and it will go unnoticed. KASAN has an ability to
> do custom poisoning: it can poison/unpoison any memory range, and then
> detect any reads/writes to that range. What do you think about adding
> custom KASAN poisoning to pskb_may_pull() and switching it to
> non-eager mode (pull only what was requested) under KASAN? Do you
> think it has potential for finding important bugs? What amount of work
> is this?

Filed https://bugzilla.kernel.org/show_bug.cgi?id=199055 for this so
it's not get lost.