powerpc/powernv: Check sysfs size before copying

The sysparam code currently uses the userspace supplied number of
bytes when memcpy()ing in to a local 64-byte buffer.

Limit the maximum number of bytes by the size of the buffer.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Joel Stanley 2014-04-24 16:55:35 +09:30 committed by Benjamin Herrenschmidt
parent b8569d2304
commit 85390378f0

View File

@ -135,6 +135,10 @@ static ssize_t sys_param_store(struct kobject *kobj,
kobj_attr);
ssize_t ret;
/* MAX_PARAM_DATA_LEN is sizeof(param_data_buf) */
if (count > MAX_PARAM_DATA_LEN)
count = MAX_PARAM_DATA_LEN;
mutex_lock(&opal_sysparam_mutex);
memcpy(param_data_buf, buf, count);
ret = opal_set_sys_param(attr->param_id, attr->param_size,