2002-08-05 21:38:41

by Andries E. Brouwer

Subject: [PATCH] usb_string fix

[I thought I sent this yesterday night, but don't see it on l-k,
maybe I forgot. Sorry if I send it twice.]

Things are indeed as conjectured, and I can reproduce the situation
where usb_string() returns -EPIPE. Now that this is an internal
error code for the USB subsystem, and not meant to get out to the
user, I made these driverfs files empty in case of error.
(While if there is no error but the string has length 0,
the file will consist of a single '\n'.)

One fewer random memory corruption. Unfortunately, there are more.

Andries

diff -r -u /linux/2.5/linux-2.5.30/linux/drivers/usb/core/usb.c ./usb.c
--- /linux/2.5/linux-2.5.30/linux/drivers/usb/core/usb.c Sun Aug 4 14:16:57 2002
+++ ./usb.c Sun Aug 4 23:00:22 2002
@@ -863,9 +863,11 @@
return 0;
udev = to_usb_device (dev);

- len = usb_string(udev, udev->descriptor.iProduct, buf, PAGE_SIZE);
+ len = usb_string(udev, udev->descriptor.iProduct, buf, PAGE_SIZE);
+ if (len < 0)
+ return 0;
buf[len] = '\n';
- buf[len+1] = 0x00;
+ buf[len+1] = 0;
return len+1;
}
static DEVICE_ATTR(product,"product",S_IRUGO,show_product,NULL);
@@ -881,9 +883,11 @@
return 0;
udev = to_usb_device (dev);

- len = usb_string(udev, udev->descriptor.iManufacturer, buf, PAGE_SIZE);
+ len = usb_string(udev, udev->descriptor.iManufacturer, buf, PAGE_SIZE);
+ if (len < 0)
+ return 0;
buf[len] = '\n';
- buf[len+1] = 0x00;
+ buf[len+1] = 0;
return len+1;
}
static DEVICE_ATTR(manufacturer,"manufacturer",S_IRUGO,show_manufacturer,NULL);
@@ -899,9 +903,11 @@
return 0;
udev = to_usb_device (dev);

- len = usb_string(udev, udev->descriptor.iSerialNumber, buf, PAGE_SIZE);
+ len = usb_string(udev, udev->descriptor.iSerialNumber, buf, PAGE_SIZE);
+ if (len < 0)
+ return 0;
buf[len] = '\n';
- buf[len+1] = 0x00;
+ buf[len+1] = 0;
return len+1;
}
static DEVICE_ATTR(serial,"serial",S_IRUGO,show_serial,NULL);
@@ -918,13 +924,13 @@
unsigned claimed = 0;

/* FIXME should get called for each new configuration not just the
- * first one for a device. switching configs (or altesettings) should
+ * first one for a device. switching configs (or altsettings) should
* undo driverfs and HCD state for the previous interfaces.
*/
for (ifnum = 0; ifnum < dev->actconfig->bNumInterfaces; ifnum++) {
struct usb_interface *interface = &dev->actconfig->interface[ifnum];
struct usb_interface_descriptor *desc = interface->altsetting;
-
+
/* register this interface with driverfs */
interface->dev.parent = &dev->dev;
interface->dev.bus = &usb_bus_type;

2002-08-05 22:35:19

by Greg KH

Subject: Re: [linux-usb-devel] [PATCH] usb_string fix

On Mon, Aug 05, 2002 at 11:42:09PM +0200, [email protected] wrote:
>
> [I thought I sent this yesterday night, but don't see it on l-k,
> maybe I forgot. Sorry if I send it twice.]
>
> Things are indeed as conjectured, and I can reproduce the situation
> where usb_string() returns -EPIPE. Now that this is an internal
> error code for the USB subsystem, and not meant to get out to the
> user, I made these driverfs files empty in case of error.
> (While if there is no error but the string has length 0,
> the file will consist of a single '\n'.)
>
> One fewer random memory corruption. Unfortunately, there are more.

Thanks for the fix, I've applied it to my trees.

greg k-h