Re: [PATCH] kill access_ok() call from copy_siginfo_to_user() thatwe might as well avoid.

From: Jesper Juhl
Date: Mon Dec 20 2004 - 19:33:13 EST

On Mon, 20 Dec 2004, Linus Torvalds wrote:

> On Tue, 21 Dec 2004, Jesper Juhl wrote:
> >
> > In kernel/signal.c::copy_siginfo_to_user() we are calling access_ok()
> > unconditionally. As I see it there's no need for this since we might as
> > well just call copy_to_user() instead of __copy_to_user() later on and
> > then only get the overhead of the access_ok() check (inside
> > copy_to_user())
> No, the "access_ok()" is to protect the other side too, ie all the
> "__put_user()" calls.
> If you remove the access_ok(), you need to also change all the
> __put_user() calls to "put_user()". And then the end result will be much
> worse code than it is right now.
Hmm, right, now that you point it out that's glaringly obvious - that
slipped by me - sorry for the noice.

Jesper Juhl

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