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Date:   Tue, 28 Jun 2022 20:10:55 -0500
From:   Bjorn Helgaas <helgaas@kernel.org>
To:     ira.weiny@intel.com
Cc:     Dan Williams <dan.j.williams@intel.com>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Jonathan Cameron <Jonathan.Cameron@huawei.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Lukas Wunner <lukas@wunner.de>,
        Alison Schofield <alison.schofield@intel.com>,
        Vishal Verma <vishal.l.verma@intel.com>,
        Dave Jiang <dave.jiang@intel.com>,
        Ben Widawsky <bwidawsk@kernel.org>,
        linux-kernel@vger.kernel.org, linux-cxl@vger.kernel.org,
        linux-pci@vger.kernel.org,
        Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= <kw@linux.com>
Subject: Re: [PATCH V12 5/9] driver-core: Introduce BIN_ATTR_ADMIN_{RO,RW}
Message-ID: <20220629011055.GA1890289@bhelgaas>
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[+cc Krzysztof]

On Mon, Jun 27, 2022 at 09:15:23PM -0700, ira.weiny@intel.com wrote:
> From: Ira Weiny <ira.weiny@intel.com>
> 
> Many binary attributes need to limit access to CAP_SYS_ADMIN only; ie
> many binary attributes specify is_visible with 0400 or 0600.
> 
> Make setting the permissions of such attributes more explicit by
> defining BIN_ATTR_ADMIN_{RO,RW}.
> 
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Bjorn Helgaas <bhelgaas@google.com>
> Signed-off-by: Ira Weiny <ira.weiny@intel.com>

FWIW, this looks a lot like this previous patch:
  https://lore.kernel.org/all/20210416205856.3234481-7-kw@linux.com/

> ---
> Changes from V11:
> 	New Patch
> ---
>  include/linux/sysfs.h | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
> index e3f1e8ac1f85..fd3fe5c8c17f 100644
> --- a/include/linux/sysfs.h
> +++ b/include/linux/sysfs.h
> @@ -235,6 +235,22 @@ struct bin_attribute bin_attr_##_name = __BIN_ATTR_WO(_name, _size)
>  #define BIN_ATTR_RW(_name, _size)					\
>  struct bin_attribute bin_attr_##_name = __BIN_ATTR_RW(_name, _size)
>  
> +
> +#define __BIN_ATTR_ADMIN_RO(_name, _size) {					\
> +	.attr	= { .name = __stringify(_name), .mode = 0400 },		\
> +	.read	= _name##_read,						\
> +	.size	= _size,						\
> +}
> +
> +#define __BIN_ATTR_ADMIN_RW(_name, _size)					\
> +	__BIN_ATTR(_name, 0600, _name##_read, _name##_write, _size)
> +
> +#define BIN_ATTR_ADMIN_RO(_name, _size)					\
> +struct bin_attribute bin_attr_##_name = __BIN_ATTR_ADMIN_RO(_name, _size)
> +
> +#define BIN_ATTR_ADMIN_RW(_name, _size)					\
> +struct bin_attribute bin_attr_##_name = __BIN_ATTR_ADMIN_RW(_name, _size)
> +
>  struct sysfs_ops {
>  	ssize_t	(*show)(struct kobject *, struct attribute *, char *);
>  	ssize_t	(*store)(struct kobject *, struct attribute *, const char *, size_t);
> -- 
> 2.35.3
>