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Commit 914c6194 authored by Lv Zheng's avatar Lv Zheng Committed by Rafael J. Wysocki
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ACPI / sysfs: Update sysfs signature handling code 



This patch cleans up sysfs table signature handling code:

 1. Convert the signature handling code to use the ACPICA APIs to
    benefit from the future improvements of the APIs.

 2. Add 'filename' attribute in order to handle both BE/LE name tags.

 3. Add instance check in order to avoid the possible buffer overflow
    related to the table file name.

Signed-off-by: default avatarLv Zheng <lv.zheng@intel.com>
[ rjw: Changelog ]
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 307ecb0a

drivers/acpi/sysfs.c

+33 −29
Original line number Diff line number Diff line
@@ -314,10 +314,14 @@ static struct kobject *tables_kobj; 
static struct kobject *dynamic_tables_kobj;

static struct kobject *hotplug_kobj;



#define ACPI_MAX_TABLE_INSTANCES	999

#define ACPI_INST_SIZE			4 /* including trailing 0 */



struct acpi_table_attr {

	struct bin_attribute attr;

	char name[8];

	char name[ACPI_NAME_SIZE];

	int instance;

	char filename[ACPI_NAME_SIZE+ACPI_INST_SIZE];

	struct list_head node;

};
@@ -329,14 +333,9 @@ static ssize_t acpi_table_show(struct file *filp, struct kobject *kobj, 
	    container_of(bin_attr, struct acpi_table_attr, attr);

	struct acpi_table_header *table_header = NULL;

	acpi_status status;

	char name[ACPI_NAME_SIZE];



	if (strncmp(table_attr->name, "NULL", 4))

		memcpy(name, table_attr->name, ACPI_NAME_SIZE);

	else

		memcpy(name, "\0\0\0\0", 4);



	status = acpi_get_table(name, table_attr->instance, &table_header);

	status = acpi_get_table(table_attr->name, table_attr->instance,

				&table_header);

	if (ACPI_FAILURE(status))

		return -ENODEV;
@@ -344,38 +343,45 @@ static ssize_t acpi_table_show(struct file *filp, struct kobject *kobj, 
				       table_header, table_header->length);

}



static void acpi_table_attr_init(struct acpi_table_attr *table_attr,

static int acpi_table_attr_init(struct kobject *tables_obj,

				struct acpi_table_attr *table_attr,

				struct acpi_table_header *table_header)

{

	struct acpi_table_header *header = NULL;

	struct acpi_table_attr *attr = NULL;

	char instance_str[ACPI_INST_SIZE];



	sysfs_attr_init(&table_attr->attr.attr);

	if (table_header->signature[0] != '\0')

		memcpy(table_attr->name, table_header->signature,

		       ACPI_NAME_SIZE);

	else

		memcpy(table_attr->name, "NULL", 4);

	ACPI_MOVE_NAME(table_attr->name, table_header->signature);



	list_for_each_entry(attr, &acpi_table_attr_list, node) {

		if (!memcmp(table_attr->name, attr->name, ACPI_NAME_SIZE))

		if (ACPI_COMPARE_NAME(table_attr->name, attr->name))

			if (table_attr->instance < attr->instance)

				table_attr->instance = attr->instance;

	}

	table_attr->instance++;

	if (table_attr->instance > ACPI_MAX_TABLE_INSTANCES) {

		pr_warn("%4.4s: too many table instances\n",

			table_attr->name);

		return -ERANGE;

	}



	ACPI_MOVE_NAME(table_attr->filename, table_header->signature);

	table_attr->filename[ACPI_NAME_SIZE] = '\0';

	if (table_attr->instance > 1 || (table_attr->instance == 1 &&

					 !acpi_get_table

					 (table_header->signature, 2, &header)))

		sprintf(table_attr->name + ACPI_NAME_SIZE, "%d",

					 (table_header->signature, 2, &header))) {

		snprintf(instance_str, sizeof(instance_str), "%u",

			 table_attr->instance);

		strcat(table_attr->filename, instance_str);

	}



	table_attr->attr.size = table_header->length;

	table_attr->attr.read = acpi_table_show;

	table_attr->attr.attr.name = table_attr->name;

	table_attr->attr.attr.name = table_attr->filename;

	table_attr->attr.attr.mode = 0400;



	return;

	return sysfs_create_bin_file(tables_obj, &table_attr->attr);

}



acpi_status acpi_sysfs_table_handler(u32 event, void *table, void *context)
@@ -389,12 +395,11 @@ acpi_status acpi_sysfs_table_handler(u32 event, void *table, void *context) 
		if (!table_attr)

			return AE_NO_MEMORY;



		acpi_table_attr_init(table_attr, table);

		if (sysfs_create_bin_file(dynamic_tables_kobj,

					  &table_attr->attr)) {

		if (acpi_table_attr_init(dynamic_tables_kobj,

					 table_attr, table)) {

			kfree(table_attr);

			return AE_ERROR;

		} else

		}

		list_add_tail(&table_attr->node, &acpi_table_attr_list);

		break;

	case ACPI_TABLE_EVENT_LOAD:
@@ -437,13 +442,12 @@ static int acpi_tables_sysfs_init(void) 
		if (ACPI_FAILURE(status))

			continue;



		table_attr = NULL;

		table_attr = kzalloc(sizeof(*table_attr), GFP_KERNEL);

		if (!table_attr)

			return -ENOMEM;



		acpi_table_attr_init(table_attr, table_header);

		ret = sysfs_create_bin_file(tables_kobj, &table_attr->attr);

		ret = acpi_table_attr_init(tables_kobj,

					   table_attr, table_header);

		if (ret) {

			kfree(table_attr);

			return ret;