On Tue, Oct 03, 2017 at 12:50:08PM -0400, Alan Stern wrote: > On Tue, 3 Oct 2017, Takashi Iwai wrote: > > > > It's a dev_WARN because it indicates a potentially serious error in the > > > driver: The driver has submitted an interrupt URB to a bulk endpoint. > > > That may not sound bad, but the same check gets triggered if a driver > > > submits a bulk URB to an isochronous endpoint, or any other invalid > > > combination. > > > > > > Most likely the explanation here is that the driver doesn't bother to > > > check the endpoint type because it expects the endpoint will always be > > > interrupt. But that is not a safe strategy. USB devices and their > > > firmware should not be trusted unnecessarily. > > > > > > The best fix is, like you said, to add a sanity check in the caller. > > > > OK, but then do we have some handy helper for the check? > > As other bug reports by syzkaller suggest, there are a few other > > drivers that do the same, submitting a urb with naive assumption of > > the fixed EP for specific devices. In the end we'll need to put the > > very same checks there in multiple places. > > Perhaps we could add a helper routine that would take a list of > expected endpoint types and check that the actual endpoints match the > types. But of course, all the drivers you're talking about would have > to add a call to this helper routine. We have almost this type of function, usb_find_common_endpoints(), what's wrong with using that? Johan has already swept the tree and added a lot of these checks, odds are no one looked at the sound/ subdir... thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
