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...)
If not:
Reviewed-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
