On Thu, Jun 25, 2020 at 10:06 PM Greg Kroah-Hartman
<gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
>
> On Thu, Jun 25, 2020 at 04:51:03PM -0700, Dan Williams wrote:
> > A common pattern for using plain DEVICE_ATTR() instead of
> > DEVICE_ATTR_RO() and DEVICE_ATTR_RW() is for attributes that want to
> > limit read to only root. I.e. many users of DEVICE_ATTR() are
> > specifying 0400 or 0600 for permissions.
> >
> > Given the expectation that CAP_SYS_ADMIN is needed to access these
> > sensitive attributes and an explicit helper with the _ADMIN_ identifier
> > for DEVICE_ATTR_ADMIN_{RO,RW}.
> >
> > Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> > Cc: "Rafael J. Wysocki" <rafael.j.wysocki@xxxxxxxxx>
> > Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
> > ---
> > include/linux/device.h | 4 ++++
> > include/linux/sysfs.h | 7 +++++++
> > 2 files changed, 11 insertions(+)
> >
> > diff --git a/include/linux/device.h b/include/linux/device.h
> > index 15460a5ac024..d7c2570368fa 100644
> > --- a/include/linux/device.h
> > +++ b/include/linux/device.h
> > @@ -128,8 +128,12 @@ ssize_t device_store_bool(struct device *dev, struct device_attribute *attr,
> > __ATTR_PREALLOC(_name, _mode, _show, _store)
> > #define DEVICE_ATTR_RW(_name) \
> > struct device_attribute dev_attr_##_name = __ATTR_RW(_name)
> > +#define DEVICE_ATTR_ADMIN_RW(_name) \
> > + struct device_attribute dev_attr_##_name = __ATTR_RW_MODE(_name, 0600)
> > #define DEVICE_ATTR_RO(_name) \
> > struct device_attribute dev_attr_##_name = __ATTR_RO(_name)
> > +#define DEVICE_ATTR_ADMIN_RO(_name) \
> > + struct device_attribute dev_attr_##_name = __ATTR_RO_MODE(_name, 0400)
> > #define DEVICE_ATTR_WO(_name) \
> > struct device_attribute dev_attr_##_name = __ATTR_WO(_name)
> > #define DEVICE_ULONG_ATTR(_name, _mode, _var) \
> > diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
> > index 86067dbe7745..34e84122f635 100644
> > --- a/include/linux/sysfs.h
> > +++ b/include/linux/sysfs.h
> > @@ -123,6 +123,13 @@ struct attribute_group {
> > .show = _name##_show, \
> > }
> >
> > +#define __ATTR_RW_MODE(_name, _mode) { \
> > + .attr = { .name = __stringify(_name), \
> > + .mode = VERIFY_OCTAL_PERMISSIONS(_mode) }, \
> > + .show = _name##_show, \
> > + .store = _name##_store, \
> > +}
> > +
> > #define __ATTR_WO(_name) { \
> > .attr = { .name = __stringify(_name), .mode = 0200 }, \
> > .store = _name##_store, \
> >
>
> Nice! Want me to take this now, I know of many other places that could
> be cleaned up to use this (like the raw device bug that I just fixed...)
Sure, that'd be great.
> If not:
>
> Reviewed-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Thanks Greg.
