On Tue, Jun 03, 2014 at 06:17:33AM -0400, Mike Remski wrote:
> On 06/02/2014 01:46 PM, Johan Hovold wrote:
> > On Mon, Jun 02, 2014 at 01:11:37PM -0400, Mike Remski wrote:
> >> On 06/02/2014 12:49 PM, Johan Hovold wrote:
> >>> On Mon, Jun 02, 2014 at 12:24:44PM -0400, Mike Remski wrote:
> >>>> On 06/02/2014 12:20 PM, Johan Hovold wrote:
> >>>>> On Mon, Jun 02, 2014 at 12:02:40PM -0400, Mike Remski wrote:
> >>>>>> On 06/02/2014 11:40 AM, Johan Hovold wrote:
> >>>>>>> [ Please avoid top-posting. ]
> >>>>>>>
> >>>>>>> On Mon, Jun 02, 2014 at 11:16:11AM -0400, Mike Remski wrote:
> >>>>> The third interface lacks endpoints and crashes the ftdi_sio driver.
> >>>>> This shouldn't happen (even if you're forcing the wrong driver to bind),
> >>>>> so I'll fix it up if still broken in v3.15-rc.
> >>>>>
> >>>> Johan,
> >>>> Thanks again. Yes, the device does indeed have an FTDI embedded in it;
> >>>> they've programmed in their own ids. They supply a Windows driver for
> >>>> it, but that doesn't do me any good. :)
> >>> Not just their own ID's it seems.
> >>>
> >>> Have you tried just using the cdc-acm driver? The ports should up as
> >>> /dev/ttyACMx instead of ttyUSBx.
> >>>
> >> Not yet, next on the list.
> > You really should try this before anything else. :)
How did it go with cdc-acm?
You probably need the following commit (depending how well-supported your
old kernel is):
5b239f0aebd4d ("USB: cdc-acm: Add pseudo modem without AT
command capabilities")
in order for the device to bind.
> >> I'm suspecting that bNumEndpoints == 0 is causing endpoint[1].desc to
> >> stay at NULL (line 1567 in 3.1.4.5 source), so by the time it gets used
> >> later on, I'm hitting the NULL dereference.
> > Yeah, the code is obviously broken (also in v3.15-rc). It should
> > probably work to just return from ftdi_set_max_packet_size if
> > num_endpoints is 0 if you want to try that (or you can use your ?:
> > construct), but I should be able to fix this up properly on Wednesday.
> >
> > Thanks,
> > Johan
> Johan,
> I had a chance to play around with code over in ftdi_sio.c; adding this:
>
> if (!num_endpoints) {
> return;
> }
> after the "Number of endpoints" message gets rid of the crash,
> everything looks to be working correctly.
Good. Care to try the patch below so I can add a formal Tested-by tag as
well?
Thanks,
Johan
>From 4ddea3a573b8c15beefb67bc35c440850063d79d Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@xxxxxxxxxx>
Date: Wed, 4 Jun 2014 14:09:43 +0200
Subject: [PATCH 1/5] USB: ftdi_sio: fix null deref at port probe
Fix NULL-pointer dereference when probing an interface with no
endpoints.
These devices have two bulk endpoints per interface, but this avoids
crashing the kernel if a user forces a non-FTDI device to be probed.
Note that the iterator variable was made unsigned in order to avoid
a maybe-uninitialized compiler warning for ep_desc after the loop.
Fixes: 895f28badce9 ("USB: ftdi_sio: fix hi-speed device packet size
calculation")
Reported-by: Mike Remski <mremski@xxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # 2.3.61
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
---
drivers/usb/serial/ftdi_sio.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
index 7c6e1dedeb06..3019141397eb 100644
--- a/drivers/usb/serial/ftdi_sio.c
+++ b/drivers/usb/serial/ftdi_sio.c
@@ -1564,14 +1564,17 @@ static void ftdi_set_max_packet_size(struct usb_serial_port *port)
struct usb_device *udev = serial->dev;
struct usb_interface *interface = serial->interface;
- struct usb_endpoint_descriptor *ep_desc = &interface->cur_altsetting->endpoint[1].desc;
+ struct usb_endpoint_descriptor *ep_desc;
unsigned num_endpoints;
- int i;
+ unsigned i;
num_endpoints = interface->cur_altsetting->desc.bNumEndpoints;
dev_info(&udev->dev, "Number of endpoints %d\n", num_endpoints);
+ if (!num_endpoints)
+ return;
+
/* NOTE: some customers have programmed FT232R/FT245R devices
* with an endpoint size of 0 - not good. In this case, we
* want to override the endpoint descriptor setting and use a
--
1.8.5.5
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