[PATCH 06/11] ubifs: reorder capability check last

[Christian Göttsche]

On Mon, 25 Nov 2024 at 12:31, Richard Weinberger <richard at nod.at> wrote:
>
> ----- Ursprüngliche Mail -----
> > Von: "Christian Göttsche" <cgoettsche at seltendoof.de>
> > capable() calls refer to enabled LSMs whether to permit or deny the
> > request.  This is relevant in connection with SELinux, where a
> > capability check results in a policy decision and by default a denial
> > message on insufficient permission is issued.
> > It can lead to three undesired cases:
> >  1. A denial message is generated, even in case the operation was an
> >     unprivileged one and thus the syscall succeeded, creating noise.
> >  2. To avoid the noise from 1. the policy writer adds a rule to ignore
> >     those denial messages, hiding future syscalls, where the task
> >     performs an actual privileged operation, leading to hidden limited
> >     functionality of that task.
> >  3. To avoid the noise from 1. the policy writer adds a rule to permit
> >     the task the requested capability, while it does not need it,
> >     violating the principle of least privilege.
> >
> > Signed-off-by: Christian Göttsche <cgzones at googlemail.com>
> > ---
> > drivers/gpu/drm/panthor/panthor_drv.c | 2 +-
>
> This change is unrelated, please remove it.

Sorry, somehow these two changes got erroneously combined in a single patch.
I'll send a v2 with them split into separate ones.

>
> > fs/ubifs/budget.c                     | 5 +++--
> > 2 files changed, 4 insertions(+), 3 deletions(-)
>
> [...]
>
> > diff --git a/fs/ubifs/budget.c b/fs/ubifs/budget.c
> > index d76eb7b39f56..6137aeadec3f 100644
> > --- a/fs/ubifs/budget.c
> > +++ b/fs/ubifs/budget.c
> > @@ -256,8 +256,9 @@ long long ubifs_calc_available(const struct ubifs_info *c,
> > int min_idx_lebs)
> >  */
> > static int can_use_rp(struct ubifs_info *c)
> > {
> > -     if (uid_eq(current_fsuid(), c->rp_uid) || capable(CAP_SYS_RESOURCE) ||
> > -         (!gid_eq(c->rp_gid, GLOBAL_ROOT_GID) && in_group_p(c->rp_gid)))
> > +     if (uid_eq(current_fsuid(), c->rp_uid) ||
> > +         (!gid_eq(c->rp_gid, GLOBAL_ROOT_GID) && in_group_p(c->rp_gid)) ||
> > +         capable(CAP_SYS_RESOURCE))
> >               return 1;
> >       return 0;
> > }
>
> The UBIFS part looks ok:
>
> Acked-by: Richard Weinberger <richard at nod.at>
>
> Since I was not CC'ed to the whole series, I miss a lot of context.

The series consists of similar patches to other subsystems and a
coccinelle script addition.
See https://lore.kernel.org/linux-security-module/20241125104011.36552-11-cgoettsche@seltendoof.de/#t

> Will this series merged as a whole? By whom?
>
> Thanks,
> //richard