All of lore.kernel.org
 help / color / mirror / Atom feed
* [PATCH v2] Bluetooth: Don't initialize msft/aosp when using user channel
@ 2021-11-08 20:01 Jesse Melhuish
  2021-11-11 18:23 ` Jesse Melhuish
  2021-11-11 18:43 ` Marcel Holtmann
  0 siblings, 2 replies; 5+ messages in thread
From: Jesse Melhuish @ 2021-11-08 20:01 UTC (permalink / raw)
  To: linux-bluetooth
  Cc: Jesse Melhuish, Abhishek Pandit-Subedi, Sonny Sasaka,
	David S. Miller, Jakub Kicinski, Johan Hedberg,
	Luiz Augusto von Dentz, Marcel Holtmann, linux-kernel, netdev

A race condition is triggered when usermode control is given to
userspace before the kernel's MSFT query responds, resulting in an
unexpected response to userspace's reset command.

Issue can be observed in btmon:
< HCI Command: Vendor (0x3f|0x001e) plen 2                    #3 [hci0]
        05 01                                            ..
@ USER Open: bt_stack_manage (privileged) version 2.22  {0x0002} [hci0]
< HCI Command: Reset (0x03|0x0003) plen 0                     #4 [hci0]
> HCI Event: Command Complete (0x0e) plen 5                   #5 [hci0]
      Vendor (0x3f|0x001e) ncmd 1
	Status: Command Disallowed (0x0c)
	05                                               .
> HCI Event: Command Complete (0x0e) plen 4                   #6 [hci0]
      Reset (0x03|0x0003) ncmd 2
	Status: Success (0x00)

Signed-off-by: Jesse Melhuish <melhuishj@chromium.org>
Reviewed-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
Reviewed-by: Sonny Sasaka <sonnysasaka@chromium.org>
---

Changes in v2:
- Moved guard to the new home for this code.

 net/bluetooth/hci_sync.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c
index b794605dc882..5f1f59ac1813 100644
--- a/net/bluetooth/hci_sync.c
+++ b/net/bluetooth/hci_sync.c
@@ -3887,8 +3887,10 @@ int hci_dev_open_sync(struct hci_dev *hdev)
 	    hci_dev_test_flag(hdev, HCI_VENDOR_DIAG) && hdev->set_diag)
 		ret = hdev->set_diag(hdev, true);
 
-	msft_do_open(hdev);
-	aosp_do_open(hdev);
+	if (!hci_dev_test_flag(hdev, HCI_USER_CHANNEL)) {
+		msft_do_open(hdev);
+		aosp_do_open(hdev);
+	}
 
 	clear_bit(HCI_INIT, &hdev->flags);
 
-- 
2.31.0


^ permalink raw reply related	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2021-11-12 23:03 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-11-08 20:01 [PATCH v2] Bluetooth: Don't initialize msft/aosp when using user channel Jesse Melhuish
2021-11-11 18:23 ` Jesse Melhuish
2021-11-11 18:43 ` Marcel Holtmann
2021-11-12 22:50   ` Jesse Melhuish
2021-11-12 23:03     ` Jesse Melhuish

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.