From: Andrew Lunn Date: Fri, 26 Feb 2016 19:59:18 +0000 (+0100) Subject: UPSTREAM: nvmem: Add flag to export NVMEM to root only X-Git-Tag: firefly_0821_release~1982 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=a675088948a0e038159e22709f4bc17ea8c67c7b;p=firefly-linux-kernel-4.4.55.git 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 Acked-by: Srinivas Kandagatla Signed-off-by: Greg Kroah-Hartman Signed-off-by: Finley Xiao (cherry pick from 811b0d6538b9f26f3eb0f90fe4e6118f2480ec6f) --- diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c index de14fae6f7f6..b03690bc8f09 100644 --- a/drivers/nvmem/core.c +++ b/drivers/nvmem/core.c @@ -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); diff --git a/include/linux/nvmem-provider.h b/include/linux/nvmem-provider.h index 0b68caff1b3c..d24fefa0c11d 100644 --- 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)