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authorLv Zheng <lv.zheng@intel.com>2016-09-13 17:48:34 +0800
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2016-09-17 01:12:34 +0200
commit914c619409ea509f335add941ad515fb590ee6c5 (patch)
tree948830def054ac5c6c2d6c61afb23c1f14dcabb0 /drivers/acpi/sysfs.c
parent307ecb0aa3a24528efd1cfcea8215b2d82df6e10 (diff)
downloadlinux-914c619409ea509f335add941ad515fb590ee6c5.tar.bz2
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>
Diffstat (limited to 'drivers/acpi/sysfs.c')
-rw-r--r--drivers/acpi/sysfs.c62
1 files changed, 33 insertions, 29 deletions
diff --git a/drivers/acpi/sysfs.c b/drivers/acpi/sysfs.c
index c88d4bdf2165..703c26e7022c 100644
--- a/drivers/acpi/sysfs.c
+++ b/drivers/acpi/sysfs.c
@@ -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;