From 914c619409ea509f335add941ad515fb590ee6c5 Mon Sep 17 00:00:00 2001 From: Lv Zheng Date: Tue, 13 Sep 2016 17:48:34 +0800 Subject: [PATCH] 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 [ rjw: Changelog ] Signed-off-by: Rafael J. Wysocki --- drivers/acpi/sysfs.c | 62 +++++++++++++++++++++++--------------------- 1 file 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; -- 2.20.1