UPSTREAM: 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.

Change-Id: Ida22fb0ea22aef379e1bd0be241725eb96c31789
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Acked-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Finley Xiao <finley.xiao@rock-chips.com>
(cherry pick from 811b0d6538)
This commit is contained in:
Andrew Lunn
2016-02-26 20:59:18 +01:00
committed by Huang, Tao
parent 3a22addaef
commit a675088948
2 changed files with 56 additions and 2 deletions

View File

@@ -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);
@@ -355,8 +402,14 @@ 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 :
nvmem_rw_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);

View File

@@ -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)