Re: [BUG] media: dvb-usb-v2: gl861: WARNING in usb_submit_urb due to bogus control direction

On Mon, Aug 10, 2026 at 04:21:20PM +0800, ZW Tang wrote:
> Hi,
> 
> I am reporting a WARNING triggered by a syzkaller reproducer in the
> GL861 DVB USB driver.
> 
> Although a similar bug has been reported before, I can still trigger
> this warning on Linux 7.2-rc3 with the attached syzkaller reproducer.
> 
> The warning is emitted from usb_submit_urb() because the USB control
> transfer direction appears inconsistent:
> 
> usb 3-1: BOGUS control dir, pipe 80000280 doesn't match bRequestType c0
> WARNING: CPU: 0 PID: 4359 at drivers/usb/core/urb.c:412
> usb_submit_urb+0x117a/0x18d0 drivers/usb/core/urb.c:410
> 
> This looks like a driver-side control-message construction or
> validation issue in the GL861 DVB USB driver, rather than a USB core
> problem. The reproducer creates a dummy GL861 USB device, opens the
> corresponding I2C device, and issues an I2C_SMBUS ioctl. The execution
> path reaches gl861_i2c_master_xfer(), then gl861_ctrl_msg(), and
> finally usb_control_msg()/usb_submit_urb().
> 
> In the observed crash, the driver submits a vendor IN control request
> with bRequestType 0xc0, but USB core reports that the control pipe
> direction does not match the request direction/length. This may be
> related to insufficient validation of zero-length or malformed
> I2C/SMBus read requests before calling gl861_ctrl_msg().

Many USB implementations of I2C cannot handle IN transfers of length 0.  
Some of the USB I2C drivers have been fixed to set a flag saying that IN 
transfers of length 0 should not be accepted.  The same thing could be 
done for this driver.

Alan Stern