clk-sunxi: fix a missing-check bug in sunxi_divs_clk_setup()

mainline inclusion
from mainline-v5.3
commit fcdf445ff42f036d22178b49cf64e92d527c1330
category: bugfix
bugzilla: 13690
CVE: CVE-2019-12455

-------------------------------------------------

In sunxi_divs_clk_setup(), 'derived_name' is allocated by kstrndup().
It returns NULL when fails. 'derived_name' should be checked.
Signed-off-by: NGen Zhang <blackgod016574@gmail.com>
Signed-off-by: NMaxime Ripard <maxime.ripard@bootlin.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Reviewed-by: NYue Haibing <yuehaibing@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

drivers/clk/sunxi/clk-sunxi.c

@@ -988,6 +988,8 @@ static struct clk ** __init sunxi_divs_clk_setup(struct device_node *node,
 		if (endp) {
 			derived_name = kstrndup(clk_name, endp - clk_name,
 						GFP_KERNEL);
+			if (!derived_name)
+				return NULL;
 			factors.name = derived_name;
 		} else {
 			factors.name = clk_name;