Re: [PATCH] new setprocuid syscall

From: Peter Samuelson (
Date: Tue Feb 20 2001 - 23:19:43 EST

[BERECZ Szabolcs]
> The conclusion: it's cannot be implemented without slowdown.

Or: it cannot be implemented 100% safely and correctly without slowdown.

If you know the use you wish to put this to, and are willing to risk a
permission check somewhere being confused momentarily by a non-atomic
update of a 32-bit number (or the non-atomic update between several
32-bit numbers, which I think is less serious because then you are not
granting more than the union of the two UIDs) go ahead and patch your

> So ignore my patch.

For official kernels, I agree. They need to be as safe and
deterministic as possible, especially security-wise, and a semaphore on
every permission check would be ridiculous.

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This archive was generated by hypermail 2b29 : Fri Feb 23 2001 - 21:00:24 EST