Re: AUDIT of 2.5.15 copy_to/from_user

Alan Cox (alan@lxorguk.ukuu.org.uk)
Sun, 19 May 2002 19:20:23 +0100 (BST)

> > > After that we always use __copy_from_user() and we trust it not to fail.
> > > Is this correct, or not?
>
> > This is correct
>
> Even if another thread unmaps the page we were trying to read from between
> the access_ok() and the actual copy?

Yes.

The only check done in access_ok on x86 is the 0xC0000000->0xFFFFFFFF check
with isnt affected by remappings.
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