linux-kernel - Re: [PATCH 2/2] KEYS: Add per-user_namespace registers for persistent per-UID kerberos caches

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Fri, 02 Aug 2013 18:00:30 +0100
From:	David Howells <dhowells@...hat.com>
To:	ebiederm@...ssion.com (Eric W. Biederman)
Cc:	dhowells@...hat.com, keyrings@...ux-nfs.org,
	linux-nfs@...r.kernel.org, krbdev@....edu,
	"Serge E. Hallyn" <serge.hallyn@...ntu.com>,
	linux-kernel@...r.kernel.org, simo@...hat.com
Subject: Re: [PATCH 2/2] KEYS: Add per-user_namespace registers for persistent per-UID kerberos caches

Eric W. Biederman <ebiederm@...ssion.com> wrote:

> > Add support for per-user_namespace registers of persistent per-UID kerberos
> > caches held within the kernel.
> 
> Out of curiosity is this cache per user namspace because the key lookup
> is per user namespace?

Yes.  You can't see keys in another namespace.  I occasionally wonder if I
should make the key serial number tree per namespace so that you don't search
keys outside your namespace and can't try looking them up by ID - but it
complicates the garbage collector which iterates over the entire tree (though
it could maintain a list of per-ns trees).

> Some minor nits below. But I don't see anything particulary scary about
> this patch.  Other than seeming to make it easy for root to get my
> kerbose tickets.

Root can do that anyway with file-based ccaches, I believe.  However, you can
change the key permissions to prevent root even seeing that your keys/keyrings
exist, let alone stealing them.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/