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SubjectRe: [PATCH] isight_firmware: Avoid crash on loading invalid firmware
On Fri, Jun 6, 2008 at 7:48 PM, Matthew Garrett <mjg59@srcf.ucam.org> wrote:
> Different tools generate slightly different formats of the isight
> firmware. Ensure that the firmware buffer is not overrun, while still
> ensuring that the correct amount of data is written if trailing data is
> preseent. Fixes crash reported by Justin Mattock.
>
> Signed-off-by: Matthew Garrett <mjg@redhat.com>
>
> ---
>
> Identical to the previous patch, just acknowledges Justin Mattock's (not
> Maddock, Andrew :p) report in the changelog.
>
> diff --git a/drivers/usb/misc/isight_firmware.c b/drivers/usb/misc/isight_firmware.c
> index 390e048..9f30aa1 100644
> --- a/drivers/usb/misc/isight_firmware.c
> +++ b/drivers/usb/misc/isight_firmware.c
> @@ -39,9 +39,12 @@ 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 (!buf)
> + return -ENOMEM;
>
> if (request_firmware(&firmware, "isight.fw", &dev->dev) != 0) {
> printk(KERN_ERR "Unable to load isight firmware\n");
> @@ -59,7 +62,7 @@ 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 +74,14 @@ 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 +96,18 @@ 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
>

Also not matlock(not the T.V. show). Now onto the status: I think
there might be something going on with this patch, or the module
itself I keep getting ACPI EC: GPE storm
detected(http://bugzilla.kernel.org/show_bug.cgi?id=10724) , yesterday
I modified drivers/acpi/ec.c and was not receiving this message the
rest of the day, after applying the patch to isight_firmware and
loading, I'm receiving this message probably within 20 minutes of
being up. Now I'm not sure If it's because I modified ec.c, or not
that's causing this. I'll have to run a couple of experiments to see.
has anybody seen the same message?
regards;

--
Justin P. Mattock


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