[SRU Xenial 3/3] usb: hso: fix error handling code of hso_create_net_device

[Thadeu Lima de Souza Cascardo]

From: Dongliang Mu <mudongliangabcd at gmail.com>

The current error handling code of hso_create_net_device is
hso_free_net_device, no matter which errors lead to. For example,
WARNING in hso_free_net_device [1].

Fix this by refactoring the error handling code of
hso_create_net_device by handling different errors by different code.

[1] https://syzkaller.appspot.com/bug?id=66eff8d49af1b28370ad342787413e35bbe76efe

Reported-by: syzbot+44d53c7255bb1aea22d2 at syzkaller.appspotmail.com
Fixes: 5fcfb6d0bfcd ("hso: fix bailout in error case of probe")
Signed-off-by: Dongliang Mu <mudongliangabcd at gmail.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
(backported from commit a6ecfb39ba9d7316057cea823b196b734f6b18ca)
[cascardo: hso_free_net_device had a single parameter]
CVE-2021-37159
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo at canonical.com>
---
 drivers/net/usb/hso.c | 33 +++++++++++++++++++++++----------
 1 file changed, 23 insertions(+), 10 deletions(-)

diff --git a/drivers/net/usb/hso.c b/drivers/net/usb/hso.c
index 524279b59cc0..1cba84e8166d 100644
--- a/drivers/net/usb/hso.c
+++ b/drivers/net/usb/hso.c
@@ -2520,7 +2520,7 @@ static struct hso_device *hso_create_net_device(struct usb_interface *interface,
 			   hso_net_init);
 	if (!net) {
 		dev_err(&interface->dev, "Unable to create ethernet device\n");
-		goto exit;
+		goto err_hso_dev;
 	}
 
 	hso_net = netdev_priv(net);
@@ -2533,13 +2533,13 @@ static struct hso_device *hso_create_net_device(struct usb_interface *interface,
 				      USB_DIR_IN);
 	if (!hso_net->in_endp) {
 		dev_err(&interface->dev, "Can't find BULK IN endpoint\n");
-		goto exit;
+		goto err_net;
 	}
 	hso_net->out_endp = hso_get_ep(interface, USB_ENDPOINT_XFER_BULK,
 				       USB_DIR_OUT);
 	if (!hso_net->out_endp) {
 		dev_err(&interface->dev, "Can't find BULK OUT endpoint\n");
-		goto exit;
+		goto err_net;
 	}
 	SET_NETDEV_DEV(net, &interface->dev);
 	SET_NETDEV_DEVTYPE(net, &hso_type);
@@ -2548,18 +2548,18 @@ static struct hso_device *hso_create_net_device(struct usb_interface *interface,
 	for (i = 0; i < MUX_BULK_RX_BUF_COUNT; i++) {
 		hso_net->mux_bulk_rx_urb_pool[i] = usb_alloc_urb(0, GFP_KERNEL);
 		if (!hso_net->mux_bulk_rx_urb_pool[i])
-			goto exit;
+			goto err_mux_bulk_rx;
 		hso_net->mux_bulk_rx_buf_pool[i] = kzalloc(MUX_BULK_RX_BUF_SIZE,
 							   GFP_KERNEL);
 		if (!hso_net->mux_bulk_rx_buf_pool[i])
-			goto exit;
+			goto err_mux_bulk_rx;
 	}
 	hso_net->mux_bulk_tx_urb = usb_alloc_urb(0, GFP_KERNEL);
 	if (!hso_net->mux_bulk_tx_urb)
-		goto exit;
+		goto err_mux_bulk_rx;
 	hso_net->mux_bulk_tx_buf = kzalloc(MUX_BULK_TX_BUF_SIZE, GFP_KERNEL);
 	if (!hso_net->mux_bulk_tx_buf)
-		goto exit;
+		goto err_free_tx_urb;
 
 	add_net_device(hso_dev);
 
@@ -2567,7 +2567,7 @@ static struct hso_device *hso_create_net_device(struct usb_interface *interface,
 	result = register_netdev(net);
 	if (result) {
 		dev_err(&interface->dev, "Failed to register device\n");
-		goto exit;
+		goto err_free_tx_buf;
 	}
 
 	hso_log_port(hso_dev);
@@ -2575,8 +2575,21 @@ static struct hso_device *hso_create_net_device(struct usb_interface *interface,
 	hso_create_rfkill(hso_dev, interface);
 
 	return hso_dev;
-exit:
-	hso_free_net_device(hso_dev);
+
+err_free_tx_buf:
+	remove_net_device(hso_dev);
+	kfree(hso_net->mux_bulk_tx_buf);
+err_free_tx_urb:
+	usb_free_urb(hso_net->mux_bulk_tx_urb);
+err_mux_bulk_rx:
+	for (i = 0; i < MUX_BULK_RX_BUF_COUNT; i++) {
+		usb_free_urb(hso_net->mux_bulk_rx_urb_pool[i]);
+		kfree(hso_net->mux_bulk_rx_buf_pool[i]);
+	}
+err_net:
+	free_netdev(net);
+err_hso_dev:
+	kfree(hso_dev);
 	return NULL;
 }
 
-- 
2.25.1