Patch "USB: dummy-hcd: fix bug in stop_activity (handle ep0)" has been added to the 4.4-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    USB: dummy-hcd: fix bug in stop_activity (handle ep0)

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     usb-dummy-hcd-fix-bug-in-stop_activity-handle-ep0.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From bcdbeb844773333d2d1c08004f3b3e25921040e5 Mon Sep 17 00:00:00 2001
From: Alan Stern <stern@rowland.harvard.edu>
Date: Wed, 14 Dec 2016 14:55:56 -0500
Subject: USB: dummy-hcd: fix bug in stop_activity (handle ep0)

From: Alan Stern <stern@rowland.harvard.edu>

commit bcdbeb844773333d2d1c08004f3b3e25921040e5 upstream.

The stop_activity() routine in dummy-hcd is supposed to unlink all
active requests for every endpoint, among other things.  But it
doesn't handle ep0.  As a result, fuzz testing can generate a WARNING
like the following:

WARNING: CPU: 0 PID: 4410 at drivers/usb/gadget/udc/dummy_hcd.c:672 dummy_free_request+0x153/0x170
Modules linked in:
CPU: 0 PID: 4410 Comm: syz-executor Not tainted 4.9.0-rc7+ #32
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
 ffff88006a64ed10 ffffffff81f96b8a ffffffff41b58ab3 1ffff1000d4c9d35
 ffffed000d4c9d2d ffff880065f8ac00 0000000041b58ab3 ffffffff8598b510
 ffffffff81f968f8 0000000041b58ab3 ffffffff859410e0 ffffffff813f0590
Call Trace:
 [<     inline     >] __dump_stack lib/dump_stack.c:15
 [<ffffffff81f96b8a>] dump_stack+0x292/0x398 lib/dump_stack.c:51
 [<ffffffff812b808f>] __warn+0x19f/0x1e0 kernel/panic.c:550
 [<ffffffff812b831c>] warn_slowpath_null+0x2c/0x40 kernel/panic.c:585
 [<ffffffff830fcb13>] dummy_free_request+0x153/0x170 drivers/usb/gadget/udc/dummy_hcd.c:672
 [<ffffffff830ed1b0>] usb_ep_free_request+0xc0/0x420 drivers/usb/gadget/udc/core.c:195
 [<ffffffff83225031>] gadgetfs_unbind+0x131/0x190 drivers/usb/gadget/legacy/inode.c:1612
 [<ffffffff830ebd8f>] usb_gadget_remove_driver+0x10f/0x2b0 drivers/usb/gadget/udc/core.c:1228
 [<ffffffff830ec084>] usb_gadget_unregister_driver+0x154/0x240 drivers/usb/gadget/udc/core.c:1357

This patch fixes the problem by iterating over all the endpoints in
the driver's ep array instead of iterating over the gadget's ep_list,
which explicitly leaves out ep0.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/usb/gadget/udc/dummy_hcd.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/drivers/usb/gadget/udc/dummy_hcd.c
+++ b/drivers/usb/gadget/udc/dummy_hcd.c
@@ -330,7 +330,7 @@ static void nuke(struct dummy *dum, stru
 /* caller must hold lock */
 static void stop_activity(struct dummy *dum)
 {
-	struct dummy_ep	*ep;
+	int i;
 
 	/* prevent any more requests */
 	dum->address = 0;
@@ -338,8 +338,8 @@ static void stop_activity(struct dummy *
 	/* The timer is left running so that outstanding URBs can fail */
 
 	/* nuke any pending requests first, so driver i/o is quiesced */
-	list_for_each_entry(ep, &dum->gadget.ep_list, ep.ep_list)
-		nuke(dum, ep);
+	for (i = 0; i < DUMMY_ENDPOINTS; ++i)
+		nuke(dum, &dum->ep[i]);
 
 	/* driver now does any non-usb quiescing necessary */
 }


Patches currently in stable-queue which might be from stern@rowland.harvard.edu are

queue-4.4/usb-dummy-hcd-fix-bug-in-stop_activity-handle-ep0.patch
queue-4.4/usb-gadgetfs-fix-use-after-free-bug.patch
queue-4.4/usb-gadgetfs-fix-checks-of-wtotallength-in-config-descriptors.patch
queue-4.4/usb-fix-problems-with-duplicate-endpoint-addresses.patch
queue-4.4/usb-gadgetfs-fix-unbounded-memory-allocation-bug.patch