In btusb_mtk_setup(), we set `btmtk_data->isopkt_intf` to:
usb_ifnum_to_if(data->udev, MTK_ISO_IFNUM)
That function can return NULL in some cases. Even when it returns
NULL, though, we still go on to call btusb_mtk_claim_iso_intf().
As of commit e9087e828827 ("Bluetooth: btusb: mediatek: Add locks for
usb_driver_claim_interface()"), calling btusb_mtk_claim_iso_intf()
when `btmtk_data->isopkt_intf` is NULL will cause a crash because
we'll end up passing a bad pointer to device_lock(). Prior to that
commit we'd pass the NULL pointer directly to
usb_driver_claim_interface() which would detect it and return an
error, which was handled.
Resolve the crash in btusb_mtk_claim_iso_intf() by adding a NULL check
at the start of the function. This makes the code handle a NULL
`btmtk_data->isopkt_intf` the same way it did before the problematic
commit (just with a slight change to the error message printed).
Reported-by: IncogCyberpunk <incogcyberpunk@proton.me>
Closes: http://lore.kernel.org/r/a380d061-479e-4713-bddd-1d6571ca7e86@leemhuis.info
Fixes: e9087e828827 ("Bluetooth: btusb: mediatek: Add locks for usb_driver_claim_interface()")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
---
I have no way to test this commit myself other than to compile it. It
looks fairly straightforward, though, so I'm hopeful it will fix the
problem.
Changes in v2:
- Rebase atop commit 529ac8e706c3 ("Bluetooth: ... mtk iso interface")
drivers/bluetooth/btusb.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
index fcc62e2fb641..683ac02e964b 100644
--- a/drivers/bluetooth/btusb.c
+++ b/drivers/bluetooth/btusb.c
@@ -2751,6 +2751,11 @@ static void btusb_mtk_claim_iso_intf(struct btusb_data *data)
if (!btmtk_data)
return;
+ if (!btmtk_data->isopkt_intf) {
+ bt_dev_err(data->hdev, "Can't claim NULL iso interface");
+ return;
+ }
+
/*
* The function usb_driver_claim_interface() is documented to need
* locks held if it's not called from a probe routine. The code here
--
2.52.0.rc1.455.g30608eb744-goog