Messages in this thread | | | Date | Wed, 04 Jun 2014 10:54:28 -0400 | From | Mike Remski <> | Subject | Re: ftdi_sio BUG: NULL pointer dereference |
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On 06/04/2014 10:52 AM, Johan Hovold wrote: > On Wed, Jun 04, 2014 at 10:29:37AM -0400, Mike Remski wrote: >> On 06/04/2014 10:19 AM, Johan Hovold wrote: >>> >From 4ddea3a573b8c15beefb67bc35c440850063d79d Mon Sep 17 00:00:00 2001 >>> From: Johan Hovold <johan@kernel.org> >>> 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@mutualink.net> >>> Cc: <stable@vger.kernel.org> # 2.3.61 >>> Signed-off-by: Johan Hovold <johan@kernel.org> >>> --- >>> 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 >> Thanks Johan. I tried to get the cdc_acm working; did not have much >> luck/time (typical overcommit on workload) I will retry with the commit >> mentioned. >> I will try the patch today and get back to you. Nice on the ep_desc: >> looking at the code priv->max_packet_size is attached to the port, your >> change would use the last thing off of cur_altsetting->endpoint[], but >> I'm wondering if we should actually be setting priv->max_packet_size to >> whatever the max is of all endpoint[].desc->wMaxPacketSize? >> >> Thoughts? > This is the exact same behaviour as the old code (minus the NULL-deref). > > These device have two bulk endpoints per interface and they are supposed > to be using the same max packet size (64 or 512 depending on device and > host). > > This value is also used during depacketisation of incoming data (and > packetisation of outgoing data for legacy devices). I'm pretty convinced > you're using the wrong driver, something which would lead to corruption > of incoming data when the (non-existing) status bytes are stripped from > the stream. > > You really should try cdc-acm. > > Johan
Thanks for the explaination. Yes, I am working on trying cdc-acm.
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