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- From 811b0d6538b9f26f3eb0f90fe4e6118f2480ec6f Mon Sep 17 00:00:00 2001
- From: Andrew Lunn <andrew@lunn.ch>
- Date: Fri, 26 Feb 2016 20:59:18 +0100
- Subject: 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: Andrew Lunn <andrew@lunn.ch>
- Acked-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
- Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
- ---
- drivers/nvmem/core.c | 57 ++++++++++++++++++++++++++++++++++++++++--
- include/linux/nvmem-provider.h | 1 +
- 2 files changed, 56 insertions(+), 2 deletions(-)
- --- a/drivers/nvmem/core.c
- +++ b/drivers/nvmem/core.c
- @@ -161,6 +161,53 @@ static const struct attribute_group *nvm
- 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(cons
- 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);
-
- --- a/include/linux/nvmem-provider.h
- +++ b/include/linux/nvmem-provider.h
- @@ -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)
|
