Messages in this thread | | | Date | Sat, 18 Mar 2006 21:23:52 +0100 | From | "Jesper Juhl" <> | Subject | Re: [patch 1/2] Validate itimer timeval from userspace |
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On 3/18/06, Andrew Morton <akpm@osdl.org> wrote: > Thomas Gleixner <tglx@linutronix.de> wrote: > > > > According to the specification the timeval must be validated and > > an errorcode -EINVAL returned in case the timeval is not in canonical > > form. Before the hrtimer merge this was silently ignored by the > > timeval to jiffies conversion. The validation is done inside > > do_setitimer so all callers are catched. > > [...] > > From my reading, 2.4's sys_setitimer() will normalise the incoming timeval > rather than rejecting it. And I think 2.6.13 did that too. > > It would be bad of us to change this behaviour, even if that's what the > spec says we should do - because we can break existing applications. > > So I think we're stuck with it - we should normalise and then accept such > timevals. And we should have a big comment explaining how we differ from > the spec, and why. >
Wouldn't this only break existing applications that do incorrect things (passing invalid values) ? If that's the case I'd say breaking them is OK and we should change to follow the spec.
I don't like potential userspace breakage any more than the next guy, but if the breakage only affects buggy applications then I think it's more acceptable.
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