mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-21 16:29:59 +00:00
usb: cdc-wdm: resp_count can be 0 even if WDM_READ is set
Do not decrement resp_count if it's already 0.
We set resp_count to 0 when the device is closed. The next open and
read will try to clear the WDM_READ flag if there was leftover data
in the read buffer. This fix is necessary to prevent resubmitting
the read URB in a tight loop because resp_count becomes negative.
The bug can easily be triggered from userspace by not reading all
data in the read buffer, and then closing and reopening the chardev.
Fixes: 8dd5cd5395
("usb: cdc-wdm: avoid hanging on zero length reads")
Cc: <stable@vger.kernel.org> # 3.13
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
parent
52a6966c35
commit
f563926fed
1 changed files with 1 additions and 1 deletions
|
@ -445,7 +445,7 @@ static int clear_wdm_read_flag(struct wdm_device *desc)
|
|||
clear_bit(WDM_READ, &desc->flags);
|
||||
|
||||
/* submit read urb only if the device is waiting for it */
|
||||
if (!--desc->resp_count)
|
||||
if (!desc->resp_count || !--desc->resp_count)
|
||||
goto out;
|
||||
|
||||
set_bit(WDM_RESPONDING, &desc->flags);
|
||||
|
|
Loading…
Reference in a new issue