Re: [PATCH v2] fs: block cross-uid sticky symlinks

[Christoph Hellwig <hch@infradead.org>]

On Mon, May 31, 2010 at 08:24:23PM -0700, Kees Cook wrote:
> Well, that's what I'm trying to understand.  It sounds like there is some
> general agreement that the issue needs to be solved, but some folks do not
> want it in the core VFS.  As in, the objections aren't with how symlink
> behavior is changed, just that the changes would be in the fs/ directory.

No, it's not.  It's not a change we can make for the default that
everyone uses.  If you're keen to mess up installations you control (aka
ubuntu valuedadd viper) push it into a special LSM or rather a
non-standard rule for it.  It really doesn't matter if it's in fs/ or
security/ but it's simplify not going to happen by default.

> My rationale is that if it's in commoncaps, it's effective for everyone, so
> it might as well be in core VFS.  If the VFS objections really do boil down
> to "not in fs/" then I'm curious if doing this in commoncaps is acceptable.

If you think the objection is about having things in fs/ you're smoking
some really bad stuff.