Messages in this thread | | | Date | Wed, 22 May 2002 20:58:10 +0200 | From | Kasper Dupont <> | Subject | Re: AUDIT: copy_from_user is a deathtrap. |
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Alan Cox wrote: > > > In such case, linus, here is your "reasonable" example. For PPro, it > > is faster to copy out-of-order, and if we wanted to use that for > > copy_to_user, you'd have your example. > > I think there is a misunderstanding here. > > Nothing in the standards says that > > write(pipe_fd, halfmappedbuffer, 2*PAGE_SIZE) > > must return PAGE_SIZE on an error. What it seems to say is that it if an error > is reported then no data got written down the actual pipe itself. Putting > 4K into the pipe then reporting Esomething is not allowed. Copying 4K into > a buffer faulting and erroring with Efoo then throwing away the buffer is > allowed
write might be the easy case. But what about read? Is a failing read allowed to change the userspace memory?
-- Kasper Dupont -- der bruger for meget tid på usenet. For sending spam use mailto:razor-report@daimi.au.dk - 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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