Messages in this thread | | | Date | Wed, 18 Mar 2009 12:08:43 -0500 | From | "Serge E. Hallyn" <> | Subject | Re: [PATCH] nfsd: nfsd should drop CAP_MKNOD for non-root |
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Quoting J. Bruce Fields (bfields@fieldses.org): > From: J. Bruce Fields <bfields@citi.umich.edu> > > 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@gmail.com> > Cc: stable@kernel.org > Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Acked-by: Serge Hallyn <serue@us.ibm.com>
I assume CAP_LINUX_IMMUTABLE simply does not apply to nfs?
And, you're adding CAP_FS_MASK_B1 in anticipation of labeled nfs?
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.
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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