devlink: Add helper function for safely copy string param
Devlink string param buffer is allocated at the size of
DEVLINK_PARAM_MAX_STRING_VALUE. Add helper function which makes sure
this size is not exceeded.
Renamed DEVLINK_PARAM_MAX_STRING_VALUE to
__DEVLINK_PARAM_MAX_STRING_VALUE to emphasize that it should be used by
devlink only. The driver should use the helper function instead to
verify it doesn't exceed the allowed length.
Signed-off-by: Moshe Shemesh <moshe@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/devlink.c b/net/core/devlink.c
index 1a0de16..6bc4293 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -3015,7 +3015,7 @@ devlink_param_value_get_from_info(const struct devlink_param *param,
len = strnlen(nla_data(info->attrs[DEVLINK_ATTR_PARAM_VALUE_DATA]),
nla_len(info->attrs[DEVLINK_ATTR_PARAM_VALUE_DATA]));
if (len == nla_len(info->attrs[DEVLINK_ATTR_PARAM_VALUE_DATA]) ||
- len >= DEVLINK_PARAM_MAX_STRING_VALUE)
+ len >= __DEVLINK_PARAM_MAX_STRING_VALUE)
return -EINVAL;
strcpy(value->vstr,
nla_data(info->attrs[DEVLINK_ATTR_PARAM_VALUE_DATA]));
@@ -4618,6 +4618,23 @@ void devlink_param_value_changed(struct devlink *devlink, u32 param_id)
EXPORT_SYMBOL_GPL(devlink_param_value_changed);
/**
+ * devlink_param_value_str_fill - Safely fill-up the string preventing
+ * from overflow of the preallocated buffer
+ *
+ * @dst_val: destination devlink_param_value
+ * @src: source buffer
+ */
+void devlink_param_value_str_fill(union devlink_param_value *dst_val,
+ const char *src)
+{
+ size_t len;
+
+ len = strlcpy(dst_val->vstr, src, __DEVLINK_PARAM_MAX_STRING_VALUE);
+ WARN_ON(len >= __DEVLINK_PARAM_MAX_STRING_VALUE);
+}
+EXPORT_SYMBOL_GPL(devlink_param_value_str_fill);
+
+/**
* devlink_region_create - create a new address region
*
* @devlink: devlink
