[PATCH] nvmem: core: constify 'struct bin_attribute'
From: Thomas Weißschuh
Date: Thu Dec 05 2024 - 12:01:13 EST
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: Thomas Weißschuh <linux@xxxxxxxxxxxxxx>
---
The usage of read_new/write_new/bin_attrs_new is a transition mechanism
and will be reverted after the transition is complete.
---
drivers/nvmem/core.c | 35 +++++++++++++++++++----------------
1 file changed, 19 insertions(+), 16 deletions(-)
diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index d6494dfc20a7324bde6415776dcabbb0bfdd334b..fd09f1a6917fe8a43cc7b112d3611b1e000c7c16 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -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,
- sizeof(struct bin_attribute *), GFP_KERNEL);
- if (!group.bin_attrs) {
+ pattrs = devm_kcalloc(&nvmem->dev, ncells + 1,
+ sizeof(struct bin_attribute *), GFP_KERNEL);
+ 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;
---
base-commit: bcc8eda6d34934d80b96adb8dc4ff5dfc632a53a
change-id: 20241201-sysfs-const-bin_attr-nvmem-8129575c369e
Best regards,
--
Thomas Weißschuh <linux@xxxxxxxxxxxxxx>