Bluetooth: bfusb: Fix use-after-free and memory leak in device lifecycle

The driver stores a reference to the usb_device structure (udev) in its private data (data->udev), which can persist beyond the immediate context of the bfusb_probe() function.

Without proper reference count management, this can lead to two issues:

1. A use-after-free scenario if udev is accessed after its main reference count drops to zero (e.g., if the device is disconnected and the data structure is still active).
2. A memory leak if udev's reference count is not properly decremented during driver disconnect, preventing the usb_device object from being freed.

To correctly manage the udev lifetime, explicitly increment its reference count with usb_get_dev(udev) when storing it in the driver's private data. Correspondingly, decrement the reference count with usb_put_dev(data->udev) in the bfusb_disconnect() callback.

This ensures udev remains valid while referenced by the driver's private data and is properly released when no longer needed.

---
 drivers/bluetooth/bfusb.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

index 8df310983bf6..f966bd8361b0 100644
@@ -622,7 +622,7 @@ static int bfusb_probe(struct usb_interface *intf, const struct usb_device_id *i
 	if (!data)
 		return -ENOMEM;
 
-	data->udev = udev;
+	data->udev = usb_get_dev(udev);
 	data->bulk_in_ep    = bulk_in_ep->desc.bEndpointAddress;
 	data->bulk_out_ep   = bulk_out_ep->desc.bEndpointAddress;
 	data->bulk_pkt_size = le16_to_cpu(bulk_out_ep->desc.wMaxPacketSize);

@@ -701,6 +701,8 @@ static void bfusb_disconnect(struct usb_interface *intf)
 
 	usb_set_intfdata(intf, NULL);
 
+	usb_put_dev(data->udev);
+
 	bfusb_close(hdev);
 
 	hci_unregister_dev(hdev);

2.43.0

This is automated email and please do not reply to this email!

Dear submitter,

Thank you for submitting the patches to the linux bluetooth mailing list. This is a CI test results with your patch series:
PW Link:https://patchwork.kernel.org/project/bluetooth/list/?series=986088

---Test result---

Test Summary:

CheckPatch                    PENDING   0.31 seconds
GitLint                       PENDING   0.25 seconds
SubjectPrefix                 PASS      0.10 seconds
BuildKernel                   PASS      24.04 seconds
CheckAllWarning               PASS      26.67 seconds
CheckSparse                   PASS      30.04 seconds
BuildKernel32                 PASS      24.31 seconds
TestRunnerSetup               PASS      475.79 seconds
TestRunner_l2cap-tester       PASS      24.80 seconds
TestRunner_iso-tester         PASS      35.94 seconds
TestRunner_bnep-tester        PASS      5.95 seconds
TestRunner_mgmt-tester        PASS      127.54 seconds
TestRunner_rfcomm-tester      PASS      9.30 seconds
TestRunner_sco-tester         PASS      14.57 seconds
TestRunner_ioctl-tester       PASS      10.00 seconds
TestRunner_mesh-tester        FAIL      11.34 seconds
TestRunner_smp-tester         PASS      8.61 seconds
TestRunner_userchan-tester    PASS      6.13 seconds
IncrementalBuild              PENDING   0.77 seconds

Details
##############################
Test: CheckPatch - PENDING
Desc: Run checkpatch.pl script Output:

##############################
Test: GitLint - PENDING
Desc: Run gitlint
Output:

##############################
Test: TestRunner_mesh-tester - FAIL
Desc: Run mesh-tester with test-runner Output:
Total: 10, Passed: 8 (80.0%), Failed: 2, Not Run: 0

Failed Test Cases

Mesh - Send cancel - 1                               Timed out    2.076 seconds
Mesh - Send cancel - 2                               Timed out    1.996 seconds

##############################
Test: IncrementalBuild - PENDING
Desc: Incremental build with the patches in the series Output:

---
Regards,
Linux Bluetooth

…

How do you think about to add any tags (like “Fixes” and “Cc”) accordingly?
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.16-rc7#n145

Regards,
Markus