3.16.74-rc1 review patch. If anyone has any objections, please let me know.
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From: Alan Stern stern@rowland.harvard.edu
commit 31e0456de5be379b10fea0fa94a681057114a96e upstream.
The syzkaller USB fuzzer found a general-protection-fault bug in the smsusb part of the Siano DVB driver. The fault occurs during probe because the driver assumes without checking that the device has both IN and OUT endpoints and the IN endpoint is ep1.
By slightly rearranging the driver's initialization code, we can make the appropriate checks early on and thus avoid the problem. If the expected endpoints aren't present, the new code safely returns -ENODEV from the probe routine.
Signed-off-by: Alan Stern stern@rowland.harvard.edu Reported-and-tested-by: syzbot+53f029db71c19a47325a@syzkaller.appspotmail.com Reviewed-by: Johan Hovold johan@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings ben@decadent.org.uk --- drivers/media/usb/siano/smsusb.c | 33 +++++++++++++++++++------------- 1 file changed, 20 insertions(+), 13 deletions(-)
--- a/drivers/media/usb/siano/smsusb.c +++ b/drivers/media/usb/siano/smsusb.c @@ -359,6 +359,7 @@ static int smsusb_init_device(struct usb struct smsdevice_params_t params; struct smsusb_device_t *dev; int i, rc; + int in_maxp;
/* create device object */ dev = kzalloc(sizeof(struct smsusb_device_t), GFP_KERNEL); @@ -372,6 +373,24 @@ static int smsusb_init_device(struct usb dev->udev = interface_to_usbdev(intf); dev->state = SMSUSB_DISCONNECTED;
+ for (i = 0; i < intf->cur_altsetting->desc.bNumEndpoints; i++) { + struct usb_endpoint_descriptor *desc = + &intf->cur_altsetting->endpoint[i].desc; + + if (desc->bEndpointAddress & USB_DIR_IN) { + dev->in_ep = desc->bEndpointAddress; + in_maxp = usb_endpoint_maxp(desc); + } else { + dev->out_ep = desc->bEndpointAddress; + } + } + + pr_debug("in_ep = %02x, out_ep = %02x\n", dev->in_ep, dev->out_ep); + if (!dev->in_ep || !dev->out_ep) { /* Missing endpoints? */ + smsusb_term_device(intf); + return -ENODEV; + } + params.device_type = sms_get_board(board_id)->type;
switch (params.device_type) { @@ -386,24 +405,12 @@ static int smsusb_init_device(struct usb /* fall-thru */ default: dev->buffer_size = USB2_BUFFER_SIZE; - dev->response_alignment = - le16_to_cpu(dev->udev->ep_in[1]->desc.wMaxPacketSize) - - sizeof(struct sms_msg_hdr); + dev->response_alignment = in_maxp - sizeof(struct sms_msg_hdr);
params.flags |= SMS_DEVICE_FAMILY2; break; }
- for (i = 0; i < intf->cur_altsetting->desc.bNumEndpoints; i++) { - if (intf->cur_altsetting->endpoint[i].desc. bEndpointAddress & USB_DIR_IN) - dev->in_ep = intf->cur_altsetting->endpoint[i].desc.bEndpointAddress; - else - dev->out_ep = intf->cur_altsetting->endpoint[i].desc.bEndpointAddress; - } - - sms_info("in_ep = %02x, out_ep = %02x", - dev->in_ep, dev->out_ep); - params.device = &dev->udev->dev; params.buffer_size = dev->buffer_size; params.num_buffers = MAX_BUFFERS;