Re: [ 88.628451] BUG: unable to handle kernel paging request at f8dbf000 "isight_firmware"

["Justin Mattock" <justinmattock@gmail.com>]

On Fri, Jun 6, 2008 at 12:11 PM, Matthew Garrett <mjg59@srcf.ucam.org> wrote:
> Argh. My firmware image contained the 0x8001 token that indicates end of
> firmware - the ones generated by Etienne's tool don't, so the driver
> reads straight off the end of the buffer. Can you try this patch? It
> also incorporates the cleanups Andrew suggested, and should be resistant
> to malformed data.
>
> diff --git a/drivers/usb/misc/isight_firmware.c b/drivers/usb/misc/isight_firmware.c
> index 390e048..cc5943c 100644
> --- a/drivers/usb/misc/isight_firmware.c
> +++ b/drivers/usb/misc/isight_firmware.c
> @@ -39,9 +39,9 @@ static int isight_firmware_load(struct usb_interface *intf,
>        struct usb_device *dev = interface_to_usbdev(intf);
>        int llen, len, req, ret = 0;
>        const struct firmware *firmware;
> -       unsigned char *buf;
> +       unsigned char *buf = kmalloc(50, GFP_KERNEL);
>        unsigned char data[4];
> -       char *ptr;
> +       u8 *ptr;
>
>        if (request_firmware(&firmware, "isight.fw", &dev->dev) != 0) {
>                printk(KERN_ERR "Unable to load isight firmware\n");
> @@ -59,7 +59,7 @@ static int isight_firmware_load(struct usb_interface *intf,
>                goto out;
>        }
>
> -       while (1) {
> +       while (ptr+4 <= firmware->data+firmware->size) {
>                memcpy(data, ptr, 4);
>                len = (data[0] << 8 | data[1]);
>                req = (data[2] << 8 | data[3]);
> @@ -71,10 +71,14 @@ static int isight_firmware_load(struct usb_interface *intf,
>                        continue;
>
>                for (; len > 0; req += 50) {
> -                       llen = len > 50 ? 50 : len;
> +                       llen = min (len, 50);
>                        len -= llen;
> -
> -                       buf = kmalloc(llen, GFP_KERNEL);
> +                       if (ptr+llen > firmware->data+firmware->size) {
> +                               printk (KERN_ERR
> +                                       "Malformed isight firmware");
> +                               ret = -ENODEV;
> +                               goto out;
> +                       }
>                        memcpy(buf, ptr, llen);
>
>                        ptr += llen;
> @@ -89,16 +93,18 @@ static int isight_firmware_load(struct usb_interface *intf,
>                                goto out;
>                        }
>
> -                       kfree(buf);
>                }
>        }
> +
>        if (usb_control_msg
>            (dev, usb_sndctrlpipe(dev, 0), 0xa0, 0x40, 0xe600, 0, "\0", 1,
>             300) != 1) {
>                printk(KERN_ERR "isight firmware loading completion failed\n");
>                ret = -ENODEV;
>        }
> +
>  out:
> +       kfree(buf);
>        release_firmware(firmware);
>        return ret;
>  }
>
> --
> Matthew Garrett | mjg59@srcf.ucam.org
>

Sure, I'll give the patch a try,
first Give me some time to take care of some extra curricular
activities. (running)
regards;
-- 
Justin P. Mattock