4.9-stable review patch. If anyone has any objections, please let me know.
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From: Alan Stern stern@rowland.harvard.edu
commit bd729f9d67aa9a303d8925bb8c4f06af25f407d1 upstream.
The syzbot fuzzing project found a use-after-free bug in the USB core. The bug was caused by usbfs not unbinding from an interface when the USB device file was closed, which led another process to attempt the unbind later on, after the private data structure had been deallocated.
The reason usbfs did not unbind the interface at the appropriate time was because it thought the interface had never been claimed in the first place. This was caused by the fact that usb_driver_claim_interface() does not clean up properly when device_bind_driver() returns an error. Although the error code gets passed back to the caller, the iface->dev.driver pointer remains set and iface->condition remains equal to USB_INTERFACE_BOUND.
This patch adds proper error handling to usb_driver_claim_interface().
Signed-off-by: Alan Stern stern@rowland.harvard.edu Reported-by: syzbot+f84aa7209ccec829536f@syzkaller.appspotmail.com CC: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/usb/core/driver.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+)
--- a/drivers/usb/core/driver.c +++ b/drivers/usb/core/driver.c @@ -562,6 +562,21 @@ int usb_driver_claim_interface(struct us if (!lpm_disable_error) usb_unlocked_enable_lpm(udev);
+ if (retval) { + dev->driver = NULL; + usb_set_intfdata(iface, NULL); + iface->needs_remote_wakeup = 0; + iface->condition = USB_INTERFACE_UNBOUND; + + /* + * Unbound interfaces are always runtime-PM-disabled + * and runtime-PM-suspended + */ + if (driver->supports_autosuspend) + pm_runtime_disable(dev); + pm_runtime_set_suspended(dev); + } + return retval; } EXPORT_SYMBOL_GPL(usb_driver_claim_interface);