svn commit: r308748 - head/sys/netgraph

[Sepherosa Ziehau]

On Thu, Nov 17, 2016 at 10:03 PM, Bjoern A. Zeeb <bz at freebsd.org> wrote:
> Author: bz
> Date: Thu Nov 17 14:03:44 2016
> New Revision: 308748
> URL: https://svnweb.freebsd.org/changeset/base/308748
>
> Log:
>   Writing out the L2TP control packet requires 12 bytes of
>   contiguous memory but in one path we did not always guarantee this,
>   thus do a m_pullup() there.
>
>   PR:                   214385
>   Submitted by:         Joe Jones (joeknockando googlemail.com)
>   MFC after:            3 days
>
> Modified:
>   head/sys/netgraph/ng_l2tp.c
>
> Modified: head/sys/netgraph/ng_l2tp.c
> ==============================================================================
> --- head/sys/netgraph/ng_l2tp.c Thu Nov 17 11:48:07 2016        (r308747)
> +++ head/sys/netgraph/ng_l2tp.c Thu Nov 17 14:03:44 2016        (r308748)
> @@ -1544,6 +1544,16 @@ ng_l2tp_xmit_ctrl(priv_p priv, struct mb
>                         priv->stats.memoryFailures++;
>                         return (ENOBUFS);
>                 }
> +
> +               /*
> +                * The below requires 12 contiguous bytes for the L2TP header
> +                * to be written into.
> +                */
> +               m = m_pullup(m, 12);
> +               if (m == NULL) {
> +                       priv->stats.memoryFailures++;
> +                       return (ENOBUFS);
> +               }

Would it be better that we do a (m->m_len < 12) test before doing the
m_pullup()?

Thanks,
sephe

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