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DateTue, 21 Dec 2004 01:41:24 +0100 (CET)
FromJesper Juhl <>
SubjectRe: [PATCH] kill access_ok() call from copy_siginfo_to_user() that we might as well avoid.
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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