Re: [PATCH 14/19] fs: Permit FIBMAP for users with CAP_SYS_RAWIO in s_user_ns

Theodore Ts'o
2015-12-04T20:05:43Z

The fact that we need CAP_SYS_RAIO for FIBMAP is pretty silly, given
that FIEMAP does not require privileges --- and in fact the preferred
interface. Why not just simply drop the requirement for privileges
for FIBMAP?

(Seth, Serge, this isn't a real objection to your patch; but the fact
that FIBMAP requires root has always been a bit silly, and this would
be a great opportunity to simplify things a bit.)

- Ted

On Fri, Dec 04, 2015 at 01:11:43PM -0600, Serge E. Hallyn wrote:
> Quoting Seth Forshee (seth.forshee@canonical.com):
> > Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
>
> Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
>
> > ---
> > fs/ioctl.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/fs/ioctl.c b/fs/ioctl.c
> > index 5d01d2638ca5..45c371bed7ee 100644
> > --- a/fs/ioctl.c
> > +++ b/fs/ioctl.c
> > @@ -55,7 +55,7 @@ static int ioctl_fibmap(struct file *filp, int __user *p)
> > /* do we support this mess? */
> > if (!mapping->a_ops->bmap)
> > return -EINVAL;
> > - if (!capable(CAP_SYS_RAWIO))
> > + if (!ns_capable(filp->f_inode->i_sb->s_user_ns, CAP_SYS_RAWIO))
> > return -EPERM;
> > res = get_user(block, p);
> > if (res)
> > --
> > 1.9.1
> >
> > --
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