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102 lines
2.8 KiB
102 lines
2.8 KiB
8 years ago
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From 811b0d6538b9f26f3eb0f90fe4e6118f2480ec6f Mon Sep 17 00:00:00 2001
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From: Andrew Lunn <andrew@lunn.ch>
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Date: Fri, 26 Feb 2016 20:59:18 +0100
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Subject: nvmem: Add flag to export NVMEM to root only
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Legacy AT24, AT25 EEPROMs are exported in sys so that only root can
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read the contents. The EEPROMs may contain sensitive information. Add
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a flag so the provide can indicate that NVMEM should also restrict
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access to root only.
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Signed-off-by: Andrew Lunn <andrew@lunn.ch>
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Acked-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
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Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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---
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drivers/nvmem/core.c | 57 ++++++++++++++++++++++++++++++++++++++++--
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include/linux/nvmem-provider.h | 1 +
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2 files changed, 56 insertions(+), 2 deletions(-)
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--- a/drivers/nvmem/core.c
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+++ b/drivers/nvmem/core.c
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@@ -161,6 +161,53 @@ static const struct attribute_group *nvm
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NULL,
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};
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+/* default read/write permissions, root only */
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+static struct bin_attribute bin_attr_rw_root_nvmem = {
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+ .attr = {
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+ .name = "nvmem",
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+ .mode = S_IWUSR | S_IRUSR,
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+ },
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+ .read = bin_attr_nvmem_read,
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+ .write = bin_attr_nvmem_write,
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+};
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+
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+static struct bin_attribute *nvmem_bin_rw_root_attributes[] = {
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+ &bin_attr_rw_root_nvmem,
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+ NULL,
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+};
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+
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+static const struct attribute_group nvmem_bin_rw_root_group = {
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+ .bin_attrs = nvmem_bin_rw_root_attributes,
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+};
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+
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+static const struct attribute_group *nvmem_rw_root_dev_groups[] = {
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+ &nvmem_bin_rw_root_group,
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+ NULL,
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+};
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+
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+/* read only permission, root only */
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+static struct bin_attribute bin_attr_ro_root_nvmem = {
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+ .attr = {
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+ .name = "nvmem",
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+ .mode = S_IRUSR,
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+ },
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+ .read = bin_attr_nvmem_read,
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+};
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+
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+static struct bin_attribute *nvmem_bin_ro_root_attributes[] = {
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+ &bin_attr_ro_root_nvmem,
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+ NULL,
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+};
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+
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+static const struct attribute_group nvmem_bin_ro_root_group = {
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+ .bin_attrs = nvmem_bin_ro_root_attributes,
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+};
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+
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+static const struct attribute_group *nvmem_ro_root_dev_groups[] = {
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+ &nvmem_bin_ro_root_group,
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+ NULL,
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+};
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+
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static void nvmem_release(struct device *dev)
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{
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struct nvmem_device *nvmem = to_nvmem_device(dev);
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@@ -355,8 +402,14 @@ struct nvmem_device *nvmem_register(cons
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nvmem->read_only = of_property_read_bool(np, "read-only") |
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config->read_only;
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- nvmem->dev.groups = nvmem->read_only ? nvmem_ro_dev_groups :
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- nvmem_rw_dev_groups;
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+ if (config->root_only)
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+ nvmem->dev.groups = nvmem->read_only ?
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+ nvmem_ro_root_dev_groups :
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+ nvmem_rw_root_dev_groups;
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+ else
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+ nvmem->dev.groups = nvmem->read_only ?
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+ nvmem_ro_dev_groups :
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+ nvmem_rw_dev_groups;
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device_initialize(&nvmem->dev);
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--- a/include/linux/nvmem-provider.h
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+++ b/include/linux/nvmem-provider.h
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@@ -23,6 +23,7 @@ struct nvmem_config {
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const struct nvmem_cell_info *cells;
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int ncells;
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bool read_only;
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+ bool root_only;
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};
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#if IS_ENABLED(CONFIG_NVMEM)
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