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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: Lv Zheng <lv.zheng@intel.com>
[ rjw: Changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Lv Zheng 2016-09-13 17:48:34 +08:00 committed by Rafael J. Wysocki
parent 307ecb0aa3
commit 914c619409
1 changed files with 33 additions and 29 deletions
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62
drivers/acpi/sysfs.c
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@ -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,
struct acpi_table_header *table_header)
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_attr->instance);
(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)
@ -389,13 +395,12 @@ 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);
}
list_add_tail(&table_attr->node, &acpi_table_attr_list);
break;
case ACPI_TABLE_EVENT_LOAD:
case ACPI_TABLE_EVENT_UNLOAD:
@ -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;