Merge branch 'caif-fixes'

Pavel Skripkin says:

====================
This patch series fix 2 memory leaks in caif
interface.

Syzbot reported memory leak in cfserl_create().
The problem was in cfcnfg_add_phy_layer() function.
This function accepts struct cflayer *link_support and
assign it to corresponting structures, but it can fail
in some cases.

These cases must be handled to prevent leaking allocated
struct cflayer *link_support pointer, because if error accured
before assigning link_support pointer to somewhere, this pointer
must be freed.

Fail log:

[   49.051872][ T7010] caif:cfcnfg_add_phy_layer(): Too many CAIF Link Layers (max 6)
[   49.110236][ T7042] caif:cfcnfg_add_phy_layer(): Too many CAIF Link Layers (max 6)
[   49.134936][ T7045] caif:cfcnfg_add_phy_layer(): Too many CAIF Link Layers (max 6)
[   49.163083][ T7043] caif:cfcnfg_add_phy_layer(): Too many CAIF Link Layers (max 6)
[   55.248950][ T6994] kmemleak: 4 new suspected memory leaks (see /sys/kernel/debug/kmemleak)

int cfcnfg_add_phy_layer(..., struct cflayer *link_support, ...)
{
...
	/* CAIF protocol allow maximum 6 link-layers */
	for (i = 0; i < 7; i++) {
		phyid = (dev->ifindex + i) & 0x7;
		if (phyid == 0)
			continue;
		if (cfcnfg_get_phyinfo_rcu(cnfg, phyid) == NULL)
			goto got_phyid;
	}
	pr_warn("Too many CAIF Link Layers (max 6)\n");
	goto out;
...
	if (link_support != NULL) {
		link_support->id = phyid;
		layer_set_dn(frml, link_support);
		layer_set_up(link_support, frml);
		layer_set_dn(link_support, phy_layer);
		layer_set_up(phy_layer, link_support);
	}
...
}

As you can see, if cfcnfg_add_phy_layer fails before layer_set_*,
link_support becomes leaked.

So, in this series, I made cfcnfg_add_phy_layer()
return an int and added error handling code to prevent
leaking link_support pointer in caif_device_notify()
and cfusbl_device_notify() functions.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/caif/caif_dev.h

@@ -119,7 +119,7 @@ void caif_free_client(struct cflayer *adap_layer);
  * The link_support layer is used to add any Link Layer specific
  * framing.
  */
-void caif_enroll_dev(struct net_device *dev, struct caif_dev_common *caifdev,
+int caif_enroll_dev(struct net_device *dev, struct caif_dev_common *caifdev,
 			struct cflayer *link_support, int head_room,
 			struct cflayer **layer, int (**rcv_func)(
 				struct sk_buff *, struct net_device *,

include/net/caif/cfcnfg.h

@@ -62,7 +62,7 @@ void cfcnfg_remove(struct cfcnfg *cfg);
  * @fcs:	Specify if checksum is used in CAIF Framing Layer.
  * @head_room:	Head space needed by link specific protocol.
  */
-void
+int
 cfcnfg_add_phy_layer(struct cfcnfg *cnfg,
 		     struct net_device *dev, struct cflayer *phy_layer,
 		     enum cfcnfg_phy_preference pref,

include/net/caif/cfserl.h

@@ -9,4 +9,5 @@
 #include <net/caif/caif_layer.h>
 
 struct cflayer *cfserl_create(int instance, bool use_stx);
+void cfserl_release(struct cflayer *layer);
 #endif

net/caif/caif_dev.c

@@ -308,7 +308,7 @@ static void dev_flowctrl(struct net_device *dev, int on)
 	caifd_put(caifd);
 }
 
-void caif_enroll_dev(struct net_device *dev, struct caif_dev_common *caifdev,
+int caif_enroll_dev(struct net_device *dev, struct caif_dev_common *caifdev,
 		     struct cflayer *link_support, int head_room,
 		     struct cflayer **layer,
 		     int (**rcv_func)(struct sk_buff *, struct net_device *,
@@ -319,11 +319,12 @@ void caif_enroll_dev(struct net_device *dev, struct caif_dev_common *caifdev,
 	enum cfcnfg_phy_preference pref;
 	struct cfcnfg *cfg = get_cfcnfg(dev_net(dev));
 	struct caif_device_entry_list *caifdevs;
+	int res;
 
 	caifdevs = caif_device_list(dev_net(dev));
 	caifd = caif_device_alloc(dev);
 	if (!caifd)
-		return;
+		return -ENOMEM;
 	*layer = &caifd->layer;
 	spin_lock_init(&caifd->flow_lock);
 
@@ -344,7 +345,7 @@ void caif_enroll_dev(struct net_device *dev, struct caif_dev_common *caifdev,
 	strlcpy(caifd->layer.name, dev->name,
 		sizeof(caifd->layer.name));
 	caifd->layer.transmit = transmit;
-	cfcnfg_add_phy_layer(cfg,
+	res = cfcnfg_add_phy_layer(cfg,
 				dev,
 				&caifd->layer,
 				pref,
@@ -354,6 +355,7 @@ void caif_enroll_dev(struct net_device *dev, struct caif_dev_common *caifdev,
 	mutex_unlock(&caifdevs->lock);
 	if (rcv_func)
 		*rcv_func = receive;
+	return res;
 }
 EXPORT_SYMBOL(caif_enroll_dev);
 
@@ -368,6 +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));
@@ -393,8 +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;
 

net/caif/caif_usb.c

@@ -115,6 +115,11 @@ static struct cflayer *cfusbl_create(int phyid, u8 ethaddr[ETH_ALEN],
 	return (struct cflayer *) this;
 }
 
+static void cfusbl_release(struct cflayer *layer)
+{
+	kfree(layer);
+}
+
 static struct packet_type caif_usb_type __read_mostly = {
 	.type = cpu_to_be16(ETH_P_802_EX1),
 };
@@ -127,6 +132,7 @@ static int cfusbl_device_notify(struct notifier_block *me, unsigned long what,
 	struct cflayer *layer, *link_support;
 	struct usbnet *usbnet;
 	struct usb_device *usbdev;
+	int res;
 
 	/* Check whether we have a NCM device, and find its VID/PID. */
 	if (!(dev->dev.parent && dev->dev.parent->driver &&
@@ -169,8 +175,11 @@ static int cfusbl_device_notify(struct notifier_block *me, unsigned long what,
 	if (dev->num_tx_queues > 1)
 		pr_warn("USB device uses more than one tx queue\n");
 
-	caif_enroll_dev(dev, &common, link_support, CFUSB_MAX_HEADLEN,
+	res = caif_enroll_dev(dev, &common, link_support, CFUSB_MAX_HEADLEN,
 			&layer, &caif_usb_type.func);
+	if (res)
+		goto err;
+
 	if (!pack_added)
 		dev_add_pack(&caif_usb_type);
 	pack_added = true;
@@ -178,6 +187,9 @@ static int cfusbl_device_notify(struct notifier_block *me, unsigned long what,
 	strlcpy(layer->name, dev->name, sizeof(layer->name));
 
 	return 0;
+err:
+	cfusbl_release(link_support);
+	return res;
 }
 
 static struct notifier_block caif_device_notifier = {

net/caif/cfcnfg.c

@@ -450,7 +450,7 @@ cfcnfg_linkup_rsp(struct cflayer *layer, u8 channel_id, enum cfctrl_srv serv,
 	rcu_read_unlock();
 }
 
-void
+int
 cfcnfg_add_phy_layer(struct cfcnfg *cnfg,
 		     struct net_device *dev, struct cflayer *phy_layer,
 		     enum cfcnfg_phy_preference pref,
@@ -459,7 +459,7 @@ cfcnfg_add_phy_layer(struct cfcnfg *cnfg,
 {
 	struct cflayer *frml;
 	struct cfcnfg_phyinfo *phyinfo = NULL;
-	int i;
+	int i, res = 0;
 	u8 phyid;
 
 	mutex_lock(&cnfg->lock);
@@ -473,12 +473,15 @@ cfcnfg_add_phy_layer(struct cfcnfg *cnfg,
 			goto got_phyid;
 	}
 	pr_warn("Too many CAIF Link Layers (max 6)\n");
+	res = -EEXIST;
 	goto out;
 
 got_phyid:
 	phyinfo = kzalloc(sizeof(struct cfcnfg_phyinfo), GFP_ATOMIC);
-	if (!phyinfo)
+	if (!phyinfo) {
+		res = -ENOMEM;
 		goto out_err;
+	}
 
 	phy_layer->id = phyid;
 	phyinfo->pref = pref;
@@ -492,8 +495,10 @@ cfcnfg_add_phy_layer(struct cfcnfg *cnfg,
 
 	frml = cffrml_create(phyid, fcs);
 
-	if (!frml)
+	if (!frml) {
+		res = -ENOMEM;
 		goto out_err;
+	}
 	phyinfo->frm_layer = frml;
 	layer_set_up(frml, cnfg->mux);
 
@@ -511,11 +516,12 @@ cfcnfg_add_phy_layer(struct cfcnfg *cnfg,
 	list_add_rcu(&phyinfo->node, &cnfg->phys);
 out:
 	mutex_unlock(&cnfg->lock);
-	return;
+	return res;
 
 out_err:
 	kfree(phyinfo);
 	mutex_unlock(&cnfg->lock);
+	return res;
 }
 EXPORT_SYMBOL(cfcnfg_add_phy_layer);
 

net/caif/cfserl.c

@@ -31,6 +31,11 @@ static int cfserl_transmit(struct cflayer *layr, struct cfpkt *pkt);
 static void cfserl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
 			   int phyid);
 
+void cfserl_release(struct cflayer *layer)
+{
+	kfree(layer);
+}
+
 struct cflayer *cfserl_create(int instance, bool use_stx)
 {
 	struct cfserl *this = kzalloc(sizeof(struct cfserl), GFP_ATOMIC);