Commit 811b0d65 authored by Andrew Lunn's avatar Andrew Lunn Committed by Greg Kroah-Hartman
Browse files

nvmem: Add flag to export NVMEM to root only 



Legacy AT24, AT25 EEPROMs are exported in sys so that only root can
read the contents. The EEPROMs may contain sensitive information. Add
a flag so the provide can indicate that NVMEM should also restrict
access to root only.

Signed-off-by: default avatarAndrew Lunn <andrew@lunn.ch>
Acked-by: default avatarSrinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 1bb850a1

drivers/nvmem/core.c

+55 −2
Original line number Diff line number Diff line
@@ -161,6 +161,53 @@ static const struct attribute_group *nvmem_ro_dev_groups[] = { 
	NULL,

};



/* default read/write permissions, root only */

static struct bin_attribute bin_attr_rw_root_nvmem = {

	.attr	= {

		.name	= "nvmem",

		.mode	= S_IWUSR | S_IRUSR,

	},

	.read	= bin_attr_nvmem_read,

	.write	= bin_attr_nvmem_write,

};



static struct bin_attribute *nvmem_bin_rw_root_attributes[] = {

	&bin_attr_rw_root_nvmem,

	NULL,

};



static const struct attribute_group nvmem_bin_rw_root_group = {

	.bin_attrs	= nvmem_bin_rw_root_attributes,

};



static const struct attribute_group *nvmem_rw_root_dev_groups[] = {

	&nvmem_bin_rw_root_group,

	NULL,

};



/* read only permission, root only */

static struct bin_attribute bin_attr_ro_root_nvmem = {

	.attr	= {

		.name	= "nvmem",

		.mode	= S_IRUSR,

	},

	.read	= bin_attr_nvmem_read,

};



static struct bin_attribute *nvmem_bin_ro_root_attributes[] = {

	&bin_attr_ro_root_nvmem,

	NULL,

};



static const struct attribute_group nvmem_bin_ro_root_group = {

	.bin_attrs	= nvmem_bin_ro_root_attributes,

};



static const struct attribute_group *nvmem_ro_root_dev_groups[] = {

	&nvmem_bin_ro_root_group,

	NULL,

};



static void nvmem_release(struct device *dev)

{

	struct nvmem_device *nvmem = to_nvmem_device(dev);
@@ -355,7 +402,13 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config) 
	nvmem->read_only = of_property_read_bool(np, "read-only") |

			   config->read_only;



	nvmem->dev.groups = nvmem->read_only ? nvmem_ro_dev_groups :

	if (config->root_only)

		nvmem->dev.groups = nvmem->read_only ?

			nvmem_ro_root_dev_groups :

			nvmem_rw_root_dev_groups;

	else

		nvmem->dev.groups = nvmem->read_only ?

			nvmem_ro_dev_groups :

			nvmem_rw_dev_groups;



	device_initialize(&nvmem->dev);

include/linux/nvmem-provider.h

+1 −0
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ struct nvmem_config { 
	const struct nvmem_cell_info	*cells;

	int			ncells;

	bool			read_only;

	bool			root_only;

};



#if IS_ENABLED(CONFIG_NVMEM)