Re: unregistered changes to the user<->kernel API

[Alexander Viro]

On Thu, 14 Jun 2001, Richard Henderson wrote:

> Yes, I saw those.  What is the effect of O_NOFOLLOW?  To not
> follow symbolic links when opening the file.  If you open a
> regular file, in effect nothing happens.  Moreover, if these
> opens were not finding files now, the system wouldn't work.
> 
> So: the effect, I suppose, is (1) disabling some security
> within glibc, and (2) making these accesses slower since they
> will be considered O_DIRECT after the change.
> 
> Which doesn't seem that life-threatening to me.

O_NOFOLLOW is used to deal with symlink attacks. Breaking it means
that for quite a few binaries you are opening security holes. And
since it's a flagday change, you'll get the situation when no version
will work for all kernels. Bad idea, IMO.