From: "Jason A. Donenfeld" <Jason@zx2c4.com>
To: Julian Wiedmann <jwi@linux.ibm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>,
Kees Cook <keescook@google.com>, Netdev <netdev@vger.kernel.org>,
syzkaller-bugs <syzkaller-bugs@googlegroups.com>,
WireGuard mailing list <wireguard@lists.zx2c4.com>,
Eric Dumazet <edumazet@google.com>
Subject: Re: UBSAN: object-size-mismatch in wg_xmit
Date: Thu, 7 Jan 2021 19:58:33 +0100 [thread overview]
Message-ID: <CAHmME9pHRZqTXCiQT+LRRs7vFq8ARL7wq_g_HpbVToxrxHvpeg@mail.gmail.com> (raw)
In-Reply-To: <68452c93-de95-aaa6-3cac-d868a202ea6f@linux.ibm.com>
On Thu, Jan 7, 2021 at 6:02 PM Julian Wiedmann <jwi@linux.ibm.com> wrote:
>
> On 21.12.20 12:23, Jason A. Donenfeld wrote:
> > Hi Dmitry,
> >
>
> ...
>
> > fall on the border of a mapping? Is UBSAN non-deterministic as an
> > optimization? Or is there actually some mysterious UaF happening with
> > my usage of skbs that I shouldn't overlook?
> >
>
> One oddity is that wg_xmit() returns negative errnos, rather than a
> netdev_tx_t (ie. NETDEV_TX_OK or NETDEV_TX_BUSY).
>
> Any chance that the stack mis-interprets one of those custom errnos
> as NETDEV_TX_BUSY, and thus believes that it still owns the skb?
The stack trace shows the splat happening as a result of
__skb_queue_tail, called from wg_xmit, not something that happens
after wg_xmit returns.
prev parent reply other threads:[~2021-01-07 18:58 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-20 16:54 syzbot
2020-12-20 21:11 ` Jason A. Donenfeld
2020-12-21 9:14 ` Dmitry Vyukov
2020-12-21 11:23 ` Jason A. Donenfeld
2021-01-07 12:22 ` Dmitry Vyukov
2021-01-07 19:00 ` Jason A. Donenfeld
2021-01-07 19:06 ` Jeffrey Walton
2021-01-08 0:34 ` Corey Costello
2021-01-08 0:42 ` Eric Light
2021-01-08 0:44 ` Corey Costello
2021-01-08 0:50 ` Eric Light
2021-01-08 1:02 ` Phillip McMahon
2021-01-08 9:33 ` Dmitry Vyukov
2021-01-08 20:54 ` Nathan Chancellor
2021-01-08 9:30 ` Dmitry Vyukov
[not found] ` <CAGXu5j+jzmkiU_AWoTVF6e263iYSSJYUHB=Kdqh-MCfEO-aNSg@mail.gmail.com>
2021-01-09 9:46 ` Dmitry Vyukov
2021-01-09 10:49 ` Matthias Urlichs
2021-01-11 17:17 ` Dmitry Vyukov
2021-01-11 17:35 ` Jeffrey Walton
2021-01-11 17:58 ` Dmitry Vyukov
2021-01-11 18:14 ` Jeffrey Walton
2021-01-12 9:54 ` Dmitry Vyukov
2021-01-07 12:53 ` Jeffrey Walton
2021-01-07 17:01 ` Julian Wiedmann
2021-01-07 18:58 ` Jason A. Donenfeld [this message]
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