Messages in this thread | | | Date | Mon, 7 Dec 2009 12:23:46 +0000 | From | Alan Cox <> | Subject | Re: [PATCH v3] vfs: new O_NODE open flag |
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The standard udev unload is a true open barrier so has an implicit revoke() caused by the fact you cannot keep a handle to the filename open during the udev sequence (or the old driver would be pinned by a refcount and not unload).
This isn't about hard links, its about object and handle lifetimes. Ownership is also involved in the case of things like a tty device (so if you can fchmod down the handle you can break the security model).
It only works because you have a true revoke (by virtue of refcounting in the kernel driver modules)
Alan
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