• Yavuz, Tuba's avatar
    USB: gadget: f_midi: fixing a possible double-free in f_midi · 7fafcfdf
    Yavuz, Tuba authored
    It looks like there is a possibility of a double-free vulnerability on an
    error path of the f_midi_set_alt function in the f_midi driver. If the
    path is feasible then free_ep_req gets called twice:
    
             req->complete = f_midi_complete;
             err = usb_ep_queue(midi->out_ep, req, GFP_ATOMIC);
                => ...
                 usb_gadget_giveback_request
                   =>
                     f_midi_complete (CALLBACK)
                       (inside f_midi_complete, for various cases of status)
                       free_ep_req(ep, req); // first kfree
             if (err) {
                     ERROR(midi, "%s: couldn't enqueue request: %d\n",
                                 midi->out_ep->name, err);
                     free_ep_req(midi->out_ep, req); // second kfree
                     return err;
             }
    
    The double-free possibility was introduced with commit ad0d1a05
    ("usb: gadget: f_midi: fix leak on failed to enqueue out requests").
    
    Found by MOXCAFE tool.
    Signed-off-by: default avatarTuba Yavuz <tuba@ece.ufl.edu>
    Fixes: ad0d1a05 ("usb: gadget: f_midi: fix leak on failed to enqueue out requests")
    Acked-by: default avatarFelipe Balbi <felipe.balbi@linux.intel.com>
    Cc: stable <stable@vger.kernel.org>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    7fafcfdf
f_midi.c 33.1 KB