| Message ID | 20210712185436.GB326369@rowland.harvard.edu |
|---|---|
| State | New |
| Headers | show |
| Series | USB: core: Fix incorrect pipe calculation in do_proc_control() | expand |
Index: usb-devel/drivers/usb/core/devio.c =================================================================== --- usb-devel.orig/drivers/usb/core/devio.c +++ usb-devel/drivers/usb/core/devio.c @@ -1133,7 +1133,7 @@ static int do_proc_control(struct usb_de "wIndex=%04x wLength=%04x\n", ctrl->bRequestType, ctrl->bRequest, ctrl->wValue, ctrl->wIndex, ctrl->wLength); - if (ctrl->bRequestType & 0x80) { + if ((ctrl->bRequestType & USB_DIR_IN) && ctrl->wLength) { pipe = usb_rcvctrlpipe(dev, 0); snoop_urb(dev, NULL, pipe, ctrl->wLength, tmo, SUBMIT, NULL, 0);
When the user submits a control URB via usbfs, the user supplies the bRequestType value and the kernel uses it to compute the pipe value. However, do_proc_control() performs this computation incorrectly in the case where the bRequestType direction bit is set to USB_DIR_IN and the URB's transfer length is 0: The pipe's direction is also set to IN but it should be OUT, which is the direction the actual transfer will use regardless of bRequestType. Commit 5cc59c418fde ("USB: core: WARN if pipe direction != setup packet direction") added a check to compare the direction bit in the pipe value to a control URB's actual direction and to WARN if they are different. This can be triggered by the incorrect computation mentioned above, as found by syzbot. This patch fixes the computation, thus avoiding the WARNing. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Reported-and-tested-by: syzbot+72af3105289dcb4c055b@syzkaller.appspotmail.com --- Greg, I'm not sure which -stable kernels, if any, need this. It should go into any kernel which contains 5cc59c418fde. [as1963] drivers/usb/core/devio.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-)