[PATCH net v1 1/2] net: usb: lan78xx: Fix double free issue with interrupt buffer allocation

[PATCH net v1 1/2] net: usb: lan78xx: Fix double free issue with interrupt buffer allocation

[Oleksij Rempel]

In lan78xx_probe(), the buffer `buf` was being freed twice: once
implicitly through `usb_free_urb(dev->urb_intr)` with the
`URB_FREE_BUFFER` flag and again explicitly by `kfree(buf)`. This caused
a double free issue.

To resolve this, reordered `kmalloc()` and `usb_alloc_urb()` calls to
simplify the initialization sequence and removed the redundant
`kfree(buf)`.  Now, `buf` is allocated after `usb_alloc_urb()`, ensuring
it is correctly managed by  `usb_fill_int_urb()` and freed by
`usb_free_urb()` as intended.

Fixes: a6df95cae40b ("lan78xx: Fix memory allocation bug")
Cc: John Efstathiades <john.efstathiades@pebblebay.com>
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
---
 drivers/net/usb/lan78xx.c | 29 ++++++++++++++---------------
 1 file changed, 14 insertions(+), 15 deletions(-)

diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c
index 8adf77e3557e..094a47b8b97e 100644
--- a/drivers/net/usb/lan78xx.c
+++ b/drivers/net/usb/lan78xx.c
@@ -4414,29 +4414,30 @@ static int lan78xx_probe(struct usb_interface *intf,
 
 	period = ep_intr->desc.bInterval;
 	maxp = usb_maxpacket(dev->udev, dev->pipe_intr);
-	buf = kmalloc(maxp, GFP_KERNEL);
-	if (!buf) {
+
+	dev->urb_intr = usb_alloc_urb(0, GFP_KERNEL);
+	if (!dev->urb_intr) {
 		ret = -ENOMEM;
 		goto out5;
 	}
 
-	dev->urb_intr = usb_alloc_urb(0, GFP_KERNEL);
-	if (!dev->urb_intr) {
+	buf = kmalloc(maxp, GFP_KERNEL);
+	if (!buf) {
 		ret = -ENOMEM;
-		goto out6;
-	} else {
-		usb_fill_int_urb(dev->urb_intr, dev->udev,
-				 dev->pipe_intr, buf, maxp,
-				 intr_complete, dev, period);
-		dev->urb_intr->transfer_flags |= URB_FREE_BUFFER;
+		goto free_urbs;
 	}
 
+	usb_fill_int_urb(dev->urb_intr, dev->udev,
+			 dev->pipe_intr, buf, maxp,
+			 intr_complete, dev, period);
+	dev->urb_intr->transfer_flags |= URB_FREE_BUFFER;
+
 	dev->maxpacket = usb_maxpacket(dev->udev, dev->pipe_out);
 
 	/* Reject broken descriptors. */
 	if (dev->maxpacket == 0) {
 		ret = -ENODEV;
-		goto out6;
+		goto free_urbs;
 	}
 
 	/* driver requires remote-wakeup capability during autosuspend. */
@@ -4444,7 +4445,7 @@ static int lan78xx_probe(struct usb_interface *intf,
 
 	ret = lan78xx_phy_init(dev);
 	if (ret < 0)
-		goto out7;
+		goto free_urbs;
 
 	ret = register_netdev(netdev);
 	if (ret != 0) {
@@ -4466,10 +4467,8 @@ static int lan78xx_probe(struct usb_interface *intf,
 
 out8:
 	phy_disconnect(netdev->phydev);
-out7:
+free_urbs:
 	usb_free_urb(dev->urb_intr);
-out6:
-	kfree(buf);
 out5:
 	lan78xx_unbind(dev, intf);
 out4:
-- 
2.39.5

[PATCH net v1 2/2] net: usb: lan78xx: Fix memory leak on device unplug by freeing PHY device

[Oleksij Rempel]

Add calls to `phy_device_free` after `fixed_phy_unregister` to fix a
memory leak that occurs when the device is unplugged. This ensures
proper cleanup of pseudo fixed-link PHYs.

Fixes: 89b36fb5e532 ("lan78xx: Lan7801 Support for Fixed PHY")
Cc: Raghuram Chary J <raghuramchary.jallipalli@microchip.com>
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
---
 drivers/net/usb/lan78xx.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c
index 094a47b8b97e..9f191b6ce821 100644
--- a/drivers/net/usb/lan78xx.c
+++ b/drivers/net/usb/lan78xx.c
@@ -2380,6 +2380,7 @@ static int lan78xx_phy_init(struct lan78xx_net *dev)
 		if (dev->chipid == ID_REV_CHIP_ID_7801_) {
 			if (phy_is_pseudo_fixed_link(phydev)) {
 				fixed_phy_unregister(phydev);
+				phy_device_free(phydev);
 			} else {
 				phy_unregister_fixup_for_uid(PHY_KSZ9031RNX,
 							     0xfffffff0);
@@ -4246,8 +4247,10 @@ static void lan78xx_disconnect(struct usb_interface *intf)
 
 	phy_disconnect(net->phydev);
 
-	if (phy_is_pseudo_fixed_link(phydev))
+	if (phy_is_pseudo_fixed_link(phydev)) {
 		fixed_phy_unregister(phydev);
+		phy_device_free(phydev);
+	}
 
 	usb_scuttle_anchored_urbs(&dev->deferred);
 
-- 
2.39.5

Re: [PATCH net v1 1/2] net: usb: lan78xx: Fix double free issue with interrupt buffer allocation

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Sat, 16 Nov 2024 14:05:57 +0100 you wrote:
> In lan78xx_probe(), the buffer `buf` was being freed twice: once
> implicitly through `usb_free_urb(dev->urb_intr)` with the
> `URB_FREE_BUFFER` flag and again explicitly by `kfree(buf)`. This caused
> a double free issue.
> 
> To resolve this, reordered `kmalloc()` and `usb_alloc_urb()` calls to
> simplify the initialization sequence and removed the redundant
> `kfree(buf)`.  Now, `buf` is allocated after `usb_alloc_urb()`, ensuring
> it is correctly managed by  `usb_fill_int_urb()` and freed by
> `usb_free_urb()` as intended.
> 
> [...]

Here is the summary with links:
  - [net,v1,1/2] net: usb: lan78xx: Fix double free issue with interrupt buffer allocation
    https://git.kernel.org/netdev/net/c/03819abbeb11
  - [net,v1,2/2] net: usb: lan78xx: Fix memory leak on device unplug by freeing PHY device
    https://git.kernel.org/netdev/net/c/ae7370e61c5d

You are awesome, thank you!
-- 
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