Messages in this thread | | | Subject | Re: [RFC/PATCH] revoke/frevoke system calls V2 | From | Alan Cox <> | Date | Tue, 08 Aug 2006 13:13:20 +0100 |
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Ar Llu, 2006-08-07 am 22:52 +0000, ysgrifennodd David Wagner: > I'm still trying to understand the semantics of this proposed > frevoke() implementation. Can an attacker use this to forcibly > close some other processes' file descriptor? Suppose the target
No.
> process has fd 0 open and the attacker revokes the file corresponding > to fd 0; what is the state of fd 0 in the target process? Is it > closed? If the target process then open()s another file, does it
No its revoked. Just like a tty hangup
> get bound to fd 0? (Recall that open() always binds to the lowest > unused fd.) If the answers are "yes", then the security consequences > seem very scary.
Of course it doesn't. The BSD folk who added revoke were security people not idiots.
Alan
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