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media: usb: siano: Fix general protection fault in smsusb

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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
CC: <stable@vger.kernel.org>
Reviewed-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Alan Stern 2019-05-07 12:39:47 -04:00 committed by Greg Kroah-Hartman
parent 9610450ea3
commit 31e0456de5
1 changed files with 20 additions and 13 deletions
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33
drivers/media/usb/siano/smsusb.c
View file

@ -400,6 +400,7 @@ static int smsusb_init_device(struct usb_interface *intf, int board_id)
struct smsusb_device_t *dev;
void *mdev;
int i, rc;
int in_maxp;
/* create device object */
dev = kzalloc(sizeof(struct smsusb_device_t), GFP_KERNEL);
@ -411,6 +412,24 @@ static int smsusb_init_device(struct usb_interface *intf, int board_id)
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) {
@ -425,24 +444,12 @@ static int smsusb_init_device(struct usb_interface *intf, int board_id)
/* 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;
}
pr_debug("in_ep = %02x, out_ep = %02x\n",
dev->in_ep, dev->out_ep);
params.device = &dev->udev->dev;
params.usb_device = dev->udev;
params.buffer_size = dev->buffer_size;