On 2019-10-31 10:50, Steve Grubb wrote:
Hello,
TLDR; I see a lot of benefit to switching away from procfs for setting auid &
sessionid.
On Wednesday, October 30, 2019 6:03:20 PM EDT Richard Guy Briggs wrote:
> > Also, for the record, removing the audit loginuid from procfs is not
> > something to take lightly, if at all; like it or not, it's part of the
> > kernel API.
It can also be used by tools to iterate processes related to one user or
session. I use this in my Intrusion Prevention System which will land in
audit user space at some point in the future.
> Oh, I'm quite aware of how important this change is and it was discussed
> with Steve Grubb who saw the concern and value of considering such a
> disruptive change.
Actually, I advocated for syscall. I think the gist of Eric's idea was that /
proc is the intersection of many nasty problems. By relying on it, you can't
simplify the API to reduce the complexity. Almost no program actually needs
access to /proc. ps does. But almost everything else is happy without it. For
example, when you setup chroot jails, you may have to add /dev/random or /
dev/null, but almost never /proc. What does force you to add /proc is any
entry point daemon like sshd because it needs to set the loginuid. If we
switch away from /proc, then sshd or crond will no longer /require/ procfs to
be available which again simplifies the system design.
> Removing proc support for auid/ses would be a
> long-term deprecation if accepted.
It might need to just be turned into readonly for a while. But then again,
perhaps auid and session should be part of /proc/<pid>/status? Maybe this can
be done independently and ahead of the container work so there is a migration
path for things that read auid or session. TBH, maybe this should have been
done from the beginning.
How about making loginuid/contid/capcontid writable only via netlink but
still provide the /proc interface for reading? Deprecation of proc can
be left as a decision for later. This way sshd/crond/getty don't need
/proc, but the info is still there for tools that want to read it.
-Steve
- RGB
--
Richard Guy Briggs <rgb(a)redhat.com>
Sr. S/W Engineer, Kernel Security, Base Operating Systems
Remote, Ottawa, Red Hat Canada
IRC: rgb, SunRaycer
Voice: +1.647.777.2635, Internal: (81) 32635