net: dsa: sja1105: fix buffer overflow in sja1105_setup_devlink_regions()

commit fd8e899cdb5ecaf8e8ee73854a99e10807eef1de upstream.

If an error occurs in dsa_devlink_region_create(), then 'priv->regions'
array will be accessed by negative index '-1'.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Signed-off-by: Rustam Subkhankulov <subkhankulov@ispras.ru>
Fixes: bf425b82059e ("net: dsa: sja1105: expose static config as devlink region")
Link: https://lore.kernel.org/r/20220817003845.389644-1-subkhankulov@ispras.ru
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/dsa/sja1105/sja1105_devlink.c b/drivers/net/dsa/sja1105/sja1105_devlink.c
index 0569ff0..10c6fea 100644 (file)
--- a/drivers/net/dsa/sja1105/sja1105_devlink.c
+++ b/drivers/net/dsa/sja1105/sja1105_devlink.c
@@ -93,7 +93,7 @@ static int sja1105_setup_devlink_regions(struct dsa_switch *ds)
 
                region = dsa_devlink_region_create(ds, ops, 1, size);
                if (IS_ERR(region)) {
-                       while (i-- >= 0)
+                       while (--i >= 0)
                                dsa_devlink_region_destroy(priv->regions[i]);
                        return PTR_ERR(region);
                }