Messages in this thread | | | Date | Wed, 04 Jun 2014 11:12:31 -0400 | From | Mike Remski <> | Subject | Re: ftdi_sio BUG: NULL pointer dereference |
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On 06/04/2014 11:09 AM, Johan Hovold wrote: > On Wed, Jun 04, 2014 at 10:55:28AM -0400, Mike Remski wrote: >> 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 >> Sorry, forgot to add: >> Tested patch and it works as desired. > Thanks, I'll add a Tested-by tag then. > > Johan Thanks for quick response. I'll let you know the results of cdc-acm (had to pull in the commit you mentioned).
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