[PATCH] Bluetooth: bcm203x: Fix use-after-free and memory leak in device lifecycle

[PATCH] Bluetooth: bcm203x: Fix use-after-free and memory leak in device lifecycle

[Salah Triki]

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 `bcm203x_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 `bcm203x_disconnect()` callback.

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

Signed-off-by: Salah Triki <salah.triki@gmail.com>
---
 drivers/bluetooth/bcm203x.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/bluetooth/bcm203x.c b/drivers/bluetooth/bcm203x.c
index c738ad0408cb..c91eaba33905 100644
--- a/drivers/bluetooth/bcm203x.c
+++ b/drivers/bluetooth/bcm203x.c
@@ -165,7 +165,7 @@ static int bcm203x_probe(struct usb_interface *intf, const struct usb_device_id
 	if (!data)
 		return -ENOMEM;
 
-	data->udev  = udev;
+	data->udev  = usb_get_dev(udev);
 	data->state = BCM203X_LOAD_MINIDRV;
 
 	data->urb = usb_alloc_urb(0, GFP_KERNEL);
@@ -243,6 +243,8 @@ static void bcm203x_disconnect(struct usb_interface *intf)
 
 	usb_set_intfdata(intf, NULL);
 
+	usb_put_dev(data->udev);
+
 	usb_free_urb(data->urb);
 	kfree(data->fw_data);
 	kfree(data->buffer);
-- 
2.43.0

RE: Bluetooth: bcm203x: Fix use-after-free and memory leak in device lifecycle

[bluez.test.bot]

[-- Attachment #1: Type: text/plain, Size: 2296 bytes --]

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=986087

---Test result---

Test Summary:
CheckPatch                    PENDING   0.26 seconds
GitLint                       PENDING   0.23 seconds
SubjectPrefix                 PASS      0.12 seconds
BuildKernel                   PASS      24.27 seconds
CheckAllWarning               PASS      27.03 seconds
CheckSparse                   PASS      30.43 seconds
BuildKernel32                 PASS      24.47 seconds
TestRunnerSetup               PASS      483.66 seconds
TestRunner_l2cap-tester       PASS      24.91 seconds
TestRunner_iso-tester         PASS      35.99 seconds
TestRunner_bnep-tester        PASS      6.10 seconds
TestRunner_mgmt-tester        FAIL      129.17 seconds
TestRunner_rfcomm-tester      PASS      9.36 seconds
TestRunner_sco-tester         PASS      14.84 seconds
TestRunner_ioctl-tester       PASS      10.30 seconds
TestRunner_mesh-tester        FAIL      11.43 seconds
TestRunner_smp-tester         PASS      8.74 seconds
TestRunner_userchan-tester    PASS      6.23 seconds
IncrementalBuild              PENDING   0.50 seconds

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

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

##############################
Test: TestRunner_mgmt-tester - FAIL
Desc: Run mgmt-tester with test-runner
Output:
Total: 490, Passed: 485 (99.0%), Failed: 1, Not Run: 4

Failed Test Cases
LL Privacy - Set Flags 2 (Enable RL)                 Failed       0.164 seconds
##############################
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    1.961 seconds
Mesh - Send cancel - 2                               Timed out    1.998 seconds
##############################
Test: IncrementalBuild - PENDING
Desc: Incremental build with the patches in the series
Output:



---
Regards,
Linux Bluetooth

Re: [PATCH] Bluetooth: bcm203x: Fix use-after-free and memory leak in device lifecycle

[Paul Menzel]

Dear Salah,


Thank you for your patch.


Am 26.07.25 um 08:23 schrieb Salah Triki:
> 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 `bcm203x_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 `bcm203x_disconnect()` callback.
> 
> This ensures `udev` remains valid while referenced by the driver's
> private data and is properly released when no longer needed.
> 

Please add a Fixes: tag.

> Signed-off-by: Salah Triki <salah.triki@gmail.com>
> ---
>   drivers/bluetooth/bcm203x.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/bluetooth/bcm203x.c b/drivers/bluetooth/bcm203x.c
> index c738ad0408cb..c91eaba33905 100644
> --- a/drivers/bluetooth/bcm203x.c
> +++ b/drivers/bluetooth/bcm203x.c
> @@ -165,7 +165,7 @@ static int bcm203x_probe(struct usb_interface *intf, const struct usb_device_id
>   	if (!data)
>   		return -ENOMEM;
>   
> -	data->udev  = udev;
> +	data->udev  = usb_get_dev(udev);
>   	data->state = BCM203X_LOAD_MINIDRV;
>   
>   	data->urb = usb_alloc_urb(0, GFP_KERNEL);
> @@ -243,6 +243,8 @@ static void bcm203x_disconnect(struct usb_interface *intf)
>   
>   	usb_set_intfdata(intf, NULL);
>   
> +	usb_put_dev(data->udev);
> +
>   	usb_free_urb(data->urb);
>   	kfree(data->fw_data);
>   	kfree(data->buffer);

The diff looks good to me, though other Bluetooth drivers seem to use 
`interface_to_usbdev(intf)`.


Kind regards,

Paul