Re: [PATCH] protect against buggy drivers

From: Greg KH (greg_at_kroah.com)
Date: 10/08/04

  • Next message: shankar krishnamurthy: "character device interface to existing socket interface." 
    Date:	Fri, 8 Oct 2004 10:50:58 -0700
To: "Richard B. Johnson" <root@chaos.analogic.com>

    On Fri, Oct 08, 2004 at 01:29:40PM -0400, Richard B. Johnson wrote:
    > On Fri, 8 Oct 2004, Greg KH wrote:
    >
    > >On Fri, Oct 08, 2004 at 09:53:41AM -0700, Stephen Hemminger wrote:
    > >>+ strlen(name) >= KOBJ_NAME_LEN ||
    > >
    > >There's no need for this check, if we fix the other usage of
    > >cdev->kobj.name in this file to use the proper kobject_name() and
    > >kobject_set_name() functions.
    >
    > Well the module name is passed in register/unregister_chrdev(). It
    > was not documented as the allowed length of the name so it was
    > possible to install a device and then only "partially" uninstall
    > the device so a subsequent open of the device-file would crash
    > the kernel. A device name of :
    >
    > "Octrangle Contrabulator" 23 characters
    >
    > ... in a test program was sufficiently-long to kill the kernel.
    > I recommend truncating any name to an acceptable length. This
    > would show up in /proc/iomem, etc., prompting the developer
    > to shorten the name.
    >
    > Also, the new length of 20 characters is probably too short.
    > There was no such limitation on 2.4.x, where many modules
    > are being ported from.

    That's why I said this check should not go in, and the cdev code fixed
    to use the proper functions. That would enable you to have as long as a
    name as you wanted to.

    thanks,

    greg k-h
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  • Next message: shankar krishnamurthy: "character device interface to existing socket interface."

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