On Wed, Mar 18, 2009 at 12:08:43PM -0500, Serge E. Hallyn wrote:
> Quoting J. Bruce Fields (bfields@xxxxxxxxxxxx):
> > From: J. Bruce Fields <bfields@xxxxxxxxxxxxxx>
> >
> > Since creating a device node is normally an operation requiring special
> > privilege, Igor Zhbanov points out that it is surprising (to say the
> > least) that a client can, for example, create a device node on a
> > filesystem exported with root_squash.
> >
> > So, make sure CAP_MKNOD is among the capabilities dropped when an nfsd
> > thread handles a request from a non-root user.
> >
> > Reported-by: Igor Zhbanov <izh1979@xxxxxxxxx>
> > Cc: stable@xxxxxxxxxx
> > Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxxxxxx>
>
> Acked-by: Serge Hallyn <serue@xxxxxxxxxx>
>
> I assume CAP_LINUX_IMMUTABLE simply does not apply to nfs?
Right. We shouldn't care how it's set.
> And, you're adding CAP_FS_MASK_B1 in anticipation of labeled nfs?
That's unchanged (would have been clearer if I hadn't re-line-wrapped in
the same patch).
> Though, I was going to send a patch later today or tomorrow (figure I
> should do some ltp testing) adding CAP_MKNOD to the whole
> CAP_FS_MASK_B0 (and CAP_LINUX_IMMUTABLE and CAP_FS_MASK_B1 to
> CAP_FS_SET). That will conflict with this one.
OK, feel free to revert this at that point if necessary.
--b.
>
> thanks,
> -serge
>
> > ---
> > include/linux/capability.h | 6 ++++--
> > 1 files changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/include/linux/capability.h b/include/linux/capability.h
> > index 1b98725..4864a43 100644
> > --- a/include/linux/capability.h
> > +++ b/include/linux/capability.h
> > @@ -393,8 +393,10 @@ struct cpu_vfs_cap_data {
> > # define CAP_FULL_SET ((kernel_cap_t){{ ~0, ~0 }})
> > # define CAP_INIT_EFF_SET ((kernel_cap_t){{ ~CAP_TO_MASK(CAP_SETPCAP), ~0 }})
> > # define CAP_FS_SET ((kernel_cap_t){{ CAP_FS_MASK_B0, CAP_FS_MASK_B1 } })
> > -# define CAP_NFSD_SET ((kernel_cap_t){{ CAP_FS_MASK_B0|CAP_TO_MASK(CAP_SYS_RESOURCE), \
> > - CAP_FS_MASK_B1 } })
> > +# define CAP_NFSD_SET ((kernel_cap_t){{ CAP_FS_MASK_B0 \
> > + | CAP_TO_MASK(CAP_SYS_RESOURCE) \
> > + | CAP_TO_MASK(CAP_MKNOD), \
> > + CAP_FS_MASK_B1 } })
> >
> > #endif /* _KERNEL_CAPABILITY_U32S != 2 */
> >
> > --
> > 1.6.0.4
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