[PATCH AUTOSEL 5.4 7/7] Input: powermate - fix use-after-free in powermate_config_complete

From: Sasha Levin
Date: Wed Oct 18 2023 - 11:46:21 EST


From: Javier Carrasco <javier.carrasco.cruz@xxxxxxxxx>

[ Upstream commit 5c15c60e7be615f05a45cd905093a54b11f461bc ]

syzbot has found a use-after-free bug [1] in the powermate driver. This
happens when the device is disconnected, which leads to a memory free from
the powermate_device struct. When an asynchronous control message
completes after the kfree and its callback is invoked, the lock does not
exist anymore and hence the bug.

Use usb_kill_urb() on pm->config to cancel any in-progress requests upon
device disconnection.

[1] https://syzkaller.appspot.com/bug?extid=0434ac83f907a1dbdd1e

Signed-off-by: Javier Carrasco <javier.carrasco.cruz@xxxxxxxxx>
Reported-by: syzbot+0434ac83f907a1dbdd1e@xxxxxxxxxxxxxxxxxxxxxxxxx
Link: https://lore.kernel.org/r/20230916-topic-powermate_use_after_free-v3-1-64412b81a7a2@xxxxxxxxx
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/input/misc/powermate.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/input/misc/powermate.c b/drivers/input/misc/powermate.c
index c4e0e1886061f..6b1b95d58e6b5 100644
--- a/drivers/input/misc/powermate.c
+++ b/drivers/input/misc/powermate.c
@@ -425,6 +425,7 @@ static void powermate_disconnect(struct usb_interface *intf)
pm->requires_update = 0;
usb_kill_urb(pm->irq);
input_unregister_device(pm->input);
+ usb_kill_urb(pm->config);
usb_free_urb(pm->irq);
usb_free_urb(pm->config);
powermate_free_buffers(interface_to_usbdev(intf), pm);
--
2.40.1