Il 2020-07-30 10:11 Ondrej Mosnacek ha scritto:
There are attacks possible, although possibly not for the threat
that is interesting for a regular Fedora user. A symlink is
technically still a file with some data in it (representing the path
to the target, but you can basically put an arbitrary string there),
so it could be used as a covert channel to smuggle some data between
domains. In an MLS setting, which is one of the main target use cases
of SELinux, such information leak could be a serious concern.
True, in a full MLS or strict selinux mode, symlink can be used to
sneakly pass some unwanted data between domains. But, as you stated,
this should be a non-issue for a targeted policy as used by Fedora,
So for Fedora it might indeed make sense to add some
"domain_can_read_symlinks" boolean for people who customize things
with symlinks a lot... But there might be other reasons for being
careful with symlinks that you or I haven't thought of :) I'd suggest
asking on the upstream mailing list (selinux(a)vger.kernel.org) on
if/why it's a good idea to follow the principle of least privilege
also for symlinks. You are likely to get a more educated answer there.
The boolean "can_read_symlinks" is, indeed, a very good idea. I'll ask
on upstream mailing list as you suggested.
I don't understand what is meant here... Do you have a link to
bugzilla in question?
Sorry, it was not on bugzilla, but on this same list:
Software Engineer, Platform Security - SELinux kernel
Red Hat, Inc.
Assyoma S.r.l. - www.assyoma.it
email: g.danti(a)assyoma.it - info(a)assyoma.it
GPG public key ID: FF5F32A8