Re: [x86] copy_from{to}_user question

From: yalin wang
Date: Thu Aug 20 2015 - 04:59:04 EST



> On Aug 17, 2015, at 12:16, Borislav Petkov <bp@xxxxxxx> wrote:
>
> On Mon, Aug 17, 2015 at 11:27:01AM +0800, yalin wang wrote:
>> i just want the x86 copy_from{to,in}_user() function have
>> the same behaviour as other platforms.
>
> Back to the original question from 2 mails ago:
>
> How else would we be able to use the same function in copy_to and
> copy_from variants?
>
>> and can disclose potential BUGs in kernel, if do like this.
>
> Back to my other question:
>
> Do you have any real life examples where you can trigger such bugs or is
> this only "potential"?
>
> IOW, what I *think* you're trying to do sounds to me like unnecessary
> complication with no apparent gain *at* *all*. So show me why you want
> to do it: code it up, trigger a bug and show me why your version is
> better. No "but but it might be a good idea", no "potentially maybe",
> none of that maybe stuff. Write it, send it with instructions how
> someone else can apply it and trigger the issue. Ok?
>
>
i will loop you in a patch mail, for kcore driver rely on x86 copy_to_user()
feature like this , but not true on other platforms .

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