[PATCH 0/4] listmount changes
Miklos Szeredi
miklos at szeredi.hu
Wed Nov 29 10:22:03 UTC 2023
On Wed, 29 Nov 2023 at 10:53, Christian Brauner <brauner at kernel.org> wrote:
>
> On Tue, 28 Nov 2023 17:03:31 +0100, Miklos Szeredi wrote:
> > This came out from me thinking about the best libc API. It contains a few
> > changes that simplify and (I think) improve the interface.
> >
> > Tree:
> >
> > git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git#vfs.mount
> >
> > [...]
>
> Afaict, all changes as discussed. Thanks. I folded the fixes into the
> main commit. Links to the patches that were folded are in the commit
> message and explained in there as well. The final commit is now rather
> small and easy to read.
Looks good, thanks for folding the patches.
> * Remove explicit LISTMOUNT_UNREACHABLE flag (cf. [1]). That
> functionality can simply be made available by checking for required
> privileges. If the caller is sufficiently privileged then list mounts
> that can't be reached from the current root. If the caller isn't skip
> mounts that can't be reached from the current root. This also makes
> permission checking consistent with statmount() (cf. [3]).
Skipping mounts based on privileges was what the initial version did.
That inconsistency was the reason for introducing
LISTMOUNT_UNREACHABLE. The final version doesn't skip mounts based on
privileges, either all submounts are listed or the request is rejected
with -EPERM.
For the case when some submounts are inside root and some are outside
useing LSMT_ROOT should be sufficient. LSMT_ROOT won't fail due to
insufficient privileges, since by definition it lists only mounts that
are below root.
Thanks,
Miklos
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