Re: [patch 01/15] security: pass path to inode_create

Tetsuo Handa
2008-06-14T08:28:00Z

Quoting Christoph wrote:
> Well, pathname based access control is a dumb idea, and we've been
> through this N times.
I have a question for you.

Matthew Wilcox wrote:
> Yes, if someone mounts /etc onto /etc2/ and has a rule to allow them to
> access /etc/shadow, they will then be able to access /etc2/shadow as
> well (which they weren't able to under previous apparmour). But I can't
> think of a way that permits Something Bad to happen (since the contents
> of the file could have been accessed through /etc/shadow *anyway*).
No. Something Bad happens even if you use object based access controls.

Andreas Gruenbacher wrote:
> One consequence of this is that pathname-based models must control who is
> allowed to create aliases where, of course.
The object based access controls *also* have to care about pathnames,
or Something Bad happens.

Have you ever thought that the pathname plays some part of security?
Please read part 3 and part 4 of http://lkml.org/lkml/2008/4/12/63 if
you have never thought that.
"Applications depend on pathnames, not on inode's number or labels.
Thinking little of pathnames leads to serious result."

Why do you think it is a bad thing to implement an access control that
restricts pathnames?