Commit 78dc14da authored by Thomas Weißschuh's avatar Thomas Weißschuh Committed by Greg Kroah-Hartman
Browse files

nvmem: core: constify 'struct bin_attribute' 



The sysfs core now allows instances of 'struct bin_attribute' to be
moved into read-only memory. Make use of that to protect them against
accidental or malicious modifications.

Also adapt the dynamic sysfs cell logic to handle the const attributes.

Signed-off-by: default avatarThomas Weißschuh <linux@weissschuh.net>
Signed-off-by: default avatarSrinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20241230143035.265518-2-srinivas.kandagatla@linaro.org


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 90154d08

drivers/nvmem/core.c

+19 −16
Original line number Diff line number Diff line
@@ -213,7 +213,7 @@ static struct attribute *nvmem_attrs[] = { 
};



static ssize_t bin_attr_nvmem_read(struct file *filp, struct kobject *kobj,

				   struct bin_attribute *attr, char *buf,

				   const struct bin_attribute *attr, char *buf,

				   loff_t pos, size_t count)

{

	struct device *dev;
@@ -246,7 +246,7 @@ static ssize_t bin_attr_nvmem_read(struct file *filp, struct kobject *kobj, 
}



static ssize_t bin_attr_nvmem_write(struct file *filp, struct kobject *kobj,

				    struct bin_attribute *attr, char *buf,

				    const struct bin_attribute *attr, char *buf,

				    loff_t pos, size_t count)

{

	struct device *dev;
@@ -340,7 +340,7 @@ static struct nvmem_cell *nvmem_create_cell(struct nvmem_cell_entry *entry, 
					    const char *id, int index);



static ssize_t nvmem_cell_attr_read(struct file *filp, struct kobject *kobj,

				    struct bin_attribute *attr, char *buf,

				    const struct bin_attribute *attr, char *buf,

				    loff_t pos, size_t count)

{

	struct nvmem_cell_entry *entry;
@@ -374,22 +374,22 @@ static ssize_t nvmem_cell_attr_read(struct file *filp, struct kobject *kobj, 
}



/* default read/write permissions */

static struct bin_attribute bin_attr_rw_nvmem = {

static const struct bin_attribute bin_attr_rw_nvmem = {

	.attr	= {

		.name	= "nvmem",

		.mode	= 0644,

	},

	.read	= bin_attr_nvmem_read,

	.write	= bin_attr_nvmem_write,

	.read_new	= bin_attr_nvmem_read,

	.write_new	= bin_attr_nvmem_write,

};



static struct bin_attribute *nvmem_bin_attributes[] = {

static const struct bin_attribute *const nvmem_bin_attributes[] = {

	&bin_attr_rw_nvmem,

	NULL,

};



static const struct attribute_group nvmem_bin_group = {

	.bin_attrs	= nvmem_bin_attributes,

	.bin_attrs_new	= nvmem_bin_attributes,

	.attrs		= nvmem_attrs,

	.is_bin_visible = nvmem_bin_attr_is_visible,

	.bin_size	= nvmem_bin_attr_size,
@@ -401,12 +401,12 @@ static const struct attribute_group *nvmem_dev_groups[] = { 
	NULL,

};



static struct bin_attribute bin_attr_nvmem_eeprom_compat = {

static const struct bin_attribute bin_attr_nvmem_eeprom_compat = {

	.attr	= {

		.name	= "eeprom",

	},

	.read	= bin_attr_nvmem_read,

	.write	= bin_attr_nvmem_write,

	.read_new	= bin_attr_nvmem_read,

	.write_new	= bin_attr_nvmem_write,

};



/*
@@ -461,6 +461,7 @@ static int nvmem_populate_sysfs_cells(struct nvmem_device *nvmem) 
		.name	= "cells",

	};

	struct nvmem_cell_entry *entry;

	const struct bin_attribute **pattrs;

	struct bin_attribute *attrs;

	unsigned int ncells = 0, i = 0;

	int ret = 0;
@@ -472,9 +473,9 @@ static int nvmem_populate_sysfs_cells(struct nvmem_device *nvmem) 


	/* Allocate an array of attributes with a sentinel */

	ncells = list_count_nodes(&nvmem->cells);

	group.bin_attrs = devm_kcalloc(&nvmem->dev, ncells + 1,

	pattrs = devm_kcalloc(&nvmem->dev, ncells + 1,

			      sizeof(struct bin_attribute *), GFP_KERNEL);

	if (!group.bin_attrs) {

	if (!pattrs) {

		ret = -ENOMEM;

		goto unlock_mutex;

	}
@@ -494,17 +495,19 @@ static int nvmem_populate_sysfs_cells(struct nvmem_device *nvmem) 
						    entry->bit_offset);

		attrs[i].attr.mode = 0444 & nvmem_bin_attr_get_umode(nvmem);

		attrs[i].size = entry->bytes;

		attrs[i].read = &nvmem_cell_attr_read;

		attrs[i].read_new = &nvmem_cell_attr_read;

		attrs[i].private = entry;

		if (!attrs[i].attr.name) {

			ret = -ENOMEM;

			goto unlock_mutex;

		}



		group.bin_attrs[i] = &attrs[i];

		pattrs[i] = &attrs[i];

		i++;

	}



	group.bin_attrs_new = pattrs;



	ret = device_add_group(&nvmem->dev, &group);

	if (ret)

		goto unlock_mutex;