net: caif: fix memory leak in caif_device_notify

commit b53558a upstream.

In case of caif_enroll_dev() fail, allocated
link_support won't be assigned to the corresponding
structure. So simply free allocated pointer in case
of error

Fixes: 7c18d22 ("caif: Restructure how link caif link layer enroll")
Cc: stable@vger.kernel.org
Reported-and-tested-by: syzbot+7ec324747ce876a29db6@syzkaller.appspotmail.com
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

net/caif/caif_dev.c

@@ -370,6 +370,7 @@ static int caif_device_notify(struct notifier_block *me, unsigned long what,
 	struct cflayer *layer, *link_support;
 	int head_room = 0;
 	struct caif_device_entry_list *caifdevs;
+	int res;
 
 	cfg = get_cfcnfg(dev_net(dev));
 	caifdevs = caif_device_list(dev_net(dev));
@@ -395,8 +396,10 @@ static int caif_device_notify(struct notifier_block *me, unsigned long what,
 				break;
 			}
 		}
-		caif_enroll_dev(dev, caifdev, link_support, head_room,
+		res = caif_enroll_dev(dev, caifdev, link_support, head_room,
 				&layer, NULL);
+		if (res)
+			cfserl_release(link_support);
 		caifdev->flowctrl = dev_flowctrl;
 		break;