Re: AUDIT: copy_from_user is a deathtrap.

Pavel Machek
2002-05-21T20:40:10Z

Hi!

> > But as we all know, it is harder to remove a feature from Linux, than
> > to get the camel book through the eye of a needle (or something).
>
> It's possible that I'm too tired to have grasped this, but if I have,
> you're all wet. In all cases, read needs to return the number of bytes
> successfully moved. If you ask for N and 1/2 of the way through N you
> are going to get a fault, and you return SEGFAULT, now how can I ever
> find out that N/2 bytes actually made it out to me? I want to know that.
> If you are arguing that return N/2 is wrong, you are incorrect.

You passed bad pointer to the kernel. You are broken. If you want to know
that N/2 was delivered, fix your code not to pass bad pointers.
Pavel
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