diff options
authorDan Williams <dan.j.williams@intel.com>2017-04-25 12:58:31 -0700
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2017-04-27 00:27:49 +0200
commit0de0e198bc7191a0e46cf71f66fec4d07ca91396 (patch)
parent5a7ad1146caa895ad718a534399e38bd2ba721b7 (diff)
ACPI / sysfs: fix acpi_get_table() leak / acpi-sysfs denial of service
Reading an ACPI table through the /sys/firmware/acpi/tables interface more than 65,536 times leads to the following log message: ACPI Error: Table ffff88033595eaa8, Validation count is zero after increment (20170119/tbutils-423) ...and the table being unavailable until the next reboot. Add the missing acpi_put_table() so the table ->validation_count is decremented after each read. Reported-by: Anush Seetharaman <anush.seetharaman@intel.com> Fixes: 174cc7187e6f "ACPICA: Tables: Back port acpi_get_table_with_size() ..." Signed-off-by: Dan Williams <dan.j.williams@intel.com> Cc: 4.10+ <stable@vger.kernel.org> # 4.10+ Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
1 files changed, 5 insertions, 2 deletions
diff --git a/drivers/acpi/sysfs.c b/drivers/acpi/sysfs.c
index cf05ae973381..5180fef9eb49 100644
--- a/drivers/acpi/sysfs.c
+++ b/drivers/acpi/sysfs.c
@@ -333,14 +333,17 @@ 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;
+ ssize_t rc;
status = acpi_get_table(table_attr->name, table_attr->instance,
if (ACPI_FAILURE(status))
return -ENODEV;
- return memory_read_from_buffer(buf, count, &offset,
- table_header, table_header->length);
+ rc = memory_read_from_buffer(buf, count, &offset, table_header,
+ table_header->length);
+ acpi_put_table(table_header);
+ return rc;
static int acpi_table_attr_init(struct kobject *tables_obj,