Messages in this thread | | | Date | Sat, 14 Feb 2004 12:42:25 +0100 | Subject | Re: devfs vs udev, thoughts from a devfs user | From | Helge Hafting <> |
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On Sat, Feb 14, 2004 at 10:13:50AM +0100, Christian Borntraeger wrote: > Mike Bell wrote: > > On Fri, Feb 13, 2004 at 01:19:20PM -0800, Greg KH wrote: > > > > That's a pretty minor difference, from the kernel's point of view. > > > > It's basically putting the same numbers in different fields. > > > > > > Heh, that's a HUGE difference! > > > > Only from userspace's point of view. To the kernel, it's basically the > > same thing. > > No. Giving a major and minor number is simple. > Creating a device node means: you have to define a policy. Now the kernel > has to think about: > - user id > - group id > - access rights > - naming > > These are the reasons why devfsd was/is necessary for devfs. > A Kernel should only enforce a policy, it should not define it. > There is one more security-related point: We may decide to not make the device node at all, in order to prevent use of some dangerous/experimental device or driver. We can't do that if the device is auto-created.
Root is usually capable of running mknod of course, but it can be prevented. For example with a fs that starts out rw but is remounted ro with no option for going back. Or /dev on cdrom . . .
Helge Hafting - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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