net: ieee802154: nl-mac: fix check on panid

This patch fixes a null pointer derefence for panid handle by move the
check for the netlink variable directly before accessing them.

Reported-by: syzbot+d4c07de0144f6f63be3a@syzkaller.appspotmail.com
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Link: https://lore.kernel.org/r/20210228151817.95700-4-aahringo@redhat.com
Signed-off-by: Stefan Schmidt <stefan@datenfreihafen.org>

diff --git a/net/ieee802154/nl-mac.c b/net/ieee802154/nl-mac.c
index 9c640d6..0c1b077 100644 (file)
--- a/net/ieee802154/nl-mac.c
+++ b/net/ieee802154/nl-mac.c
@@ -551,9 +551,7 @@ ieee802154_llsec_parse_key_id(struct genl_info *info,
        desc->mode = nla_get_u8(info->attrs[IEEE802154_ATTR_LLSEC_KEY_MODE]);
 
        if (desc->mode == IEEE802154_SCF_KEY_IMPLICIT) {
-               if (!info->attrs[IEEE802154_ATTR_PAN_ID] &&
-                   !(info->attrs[IEEE802154_ATTR_SHORT_ADDR] ||
-                     info->attrs[IEEE802154_ATTR_HW_ADDR]))
+               if (!info->attrs[IEEE802154_ATTR_PAN_ID])
                        return -EINVAL;
 
                desc->device_addr.pan_id = nla_get_shortaddr(info->attrs[IEEE802154_ATTR_PAN_ID]);
@@ -562,6 +560,9 @@ ieee802154_llsec_parse_key_id(struct genl_info *info,
                        desc->device_addr.mode = IEEE802154_ADDR_SHORT;
                        desc->device_addr.short_addr = nla_get_shortaddr(info->attrs[IEEE802154_ATTR_SHORT_ADDR]);
                } else {
+                       if (!info->attrs[IEEE802154_ATTR_HW_ADDR])
+                               return -EINVAL;
+
                        desc->device_addr.mode = IEEE802154_ADDR_LONG;
                        desc->device_addr.extended_addr = nla_get_hwaddr(info->attrs[IEEE802154_ATTR_HW_ADDR]);
                }