From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from out3-smtp.messagingengine.com ([66.111.4.27]:38363 "EHLO out3-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753905AbeDTIUz (ORCPT ); Fri, 20 Apr 2018 04:20:55 -0400 Subject: FAILED: patch "[PATCH] USB: gadget: f_midi: fixing a possible double-free in f_midi" failed to apply to 4.4-stable tree To: tuba@ece.ufl.edu, felipe.balbi@linux.intel.com, gregkh@linuxfoundation.org, stable@vger.kernel.org Cc: From: Date: Fri, 20 Apr 2018 10:20:49 +0200 Message-ID: <152421244964171@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: The patch below does not apply to the 4.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >>From 7fafcfdf6377b18b2a726ea554d6e593ba44349f Mon Sep 17 00:00:00 2001 From: "Yavuz, Tuba" Date: Fri, 23 Mar 2018 17:00:38 +0000 Subject: [PATCH] USB: gadget: f_midi: fixing a possible double-free in f_midi 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 ad0d1a058eac ("usb: gadget: f_midi: fix leak on failed to enqueue out requests"). Found by MOXCAFE tool. Signed-off-by: Tuba Yavuz Fixes: ad0d1a058eac ("usb: gadget: f_midi: fix leak on failed to enqueue out requests") Acked-by: Felipe Balbi Cc: stable Signed-off-by: Greg Kroah-Hartman diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c index 4eb96b91cc40..e8f35db42394 100644 --- a/drivers/usb/gadget/function/f_midi.c +++ b/drivers/usb/gadget/function/f_midi.c @@ -404,7 +404,8 @@ static int f_midi_set_alt(struct usb_function *f, unsigned intf, unsigned alt) if (err) { ERROR(midi, "%s: couldn't enqueue request: %d\n", midi->out_ep->name, err); - free_ep_req(midi->out_ep, req); + if (req->buf != NULL) + free_ep_req(midi->out_ep, req); return err; } } diff --git a/drivers/usb/gadget/u_f.h b/drivers/usb/gadget/u_f.h index c3fbef2bb5db..09f90447fed5 100644 --- a/drivers/usb/gadget/u_f.h +++ b/drivers/usb/gadget/u_f.h @@ -61,7 +61,9 @@ struct usb_request *alloc_ep_req(struct usb_ep *ep, size_t len); /* Frees a usb_request previously allocated by alloc_ep_req() */ static inline void free_ep_req(struct usb_ep *ep, struct usb_request *req) { + WARN_ON(req->buf == NULL); kfree(req->buf); + req->buf = NULL; usb_ep_free_request(ep, req); }