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ACPI / sysfs: fix acpi_get_table() leak / acpi-sysfs denial of service

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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: 174cc7187e "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>
This commit is contained in:
Dan Williams 2017-04-25 12:58:31 -07:00 committed by Rafael J. Wysocki
parent 5a7ad1146c
commit 0de0e198bc
1 changed files with 5 additions and 2 deletions
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7
drivers/acpi/sysfs.c
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@ -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,
&table_header);
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,