-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Stephen Smalley wrote: > On Tue, 2008-03-25 at 07:04 -0400, Joshua Brindle wrote: >> Stephen Smalley wrote: >>> On Mon, 2008-03-24 at 16:27 -0400, Joshua Brindle wrote: >>> >>>> Stephen Smalley wrote: >>>> >>>>> On Mon, 2008-03-24 at 13:40 -0400, Joshua Brindle wrote: >>>>> >>>>> >>>>>> This implements user_transition in the toolchain. It should help on >>>>>> distro's like Ubuntu that can't use run_init due to the user not knowing >>>>>> the root password. It also seems like a more eloquent way to handle >>>>>> service restarts than assigning system_r to user accounts and having the >>>>>> daemons run as someuser:system_r:foo_t. >>>>>> >>>>>> >>>>> Yes, that's something that has been wanted in Fedora for quite some >>>>> time. >>>>> >>>>> The real issue with run_init isn't the re-authentication stage, as that >>>>> can always be disabled via pam config (and was just a weak form of >>>>> confirming user intent, not an authorization mechanism), but rather the >>>>> difficulty in transparently interposing it into all situations where >>>>> services get started/re-started. Only Gentoo seemed to have a good >>>>> story there. >>>>> >>>>> >>>>> >>>>>> This has some issues in policy due to users not always being known in >>>>>> the policy (eg., semanage users). I hope Chris or Dan will be able to >>>>>> give some suggestions there. >>>>>> >>>>>> >>>>> I'm not sure why anyone needs to add users to policy via semanage users >>>>> given the base set of generic users and the ability to map Linux users >>>>> to them via seusers aka semanage login. >>>>> >>>>> >>>>> >>>>>> The kernel patch (forthcoming after this is accepted) so far only >>>>>> implements the transition on process transitions. Later on I plan on >>>>>> doing a patch to expand role_transition to object classes (this is a >>>>>> change needed for policy rbac support to work). I suspect I'll do the >>>>>> same for user at that time. The question here is, do we think its worth >>>>>> it to do fine grained transitions like we did for range_trans? (I don't). >>>>>> >>>>>> >>>>> Offhand, I can't see a use for per-class user transitions, if that is >>>>> what you mean. >>>>> >>>>> I don't think per-class role transitions is really the fundamental >>>>> obstacle to enabling use of roles on objects - more thought is required >>>>> there. What will be fun there is role/type and user/range validation, >>>>> which presently gets to ignore everything that has object_r. >>>>> >>>>> >>>> Ah, another thing. While going through the policyrep implementation the >>>> question of object_r came up. My thought is to start adding object_r >>>> magic into the toolchain (adding all types, etc) and eventually purge >>>> object_r from the kernel. at least one magic instance of object_r will >>>> be removed by object role_transitions, the others are really short >>>> circuits in the security server that can be removed after sufficient >>>> support is in the toolchain. What are your thoughts on that (for future >>>> reference)? >>>> >>> Well, the interesting question is what should the default role be in the >>> new context in security_compute_sid, if not object_r. Even aside from >>> the support for per-class role transitions. User defaults to the source >>> context, type defaults to the related object context, and MLS range >>> defaults to the low level of the source context. Role could be the >>> subject's role or the related object's role. >>> >>> >> Good question. My original assumption was that we'd use the related >> object role. That would require that home directories be correctly >> labeled with the role of the user. If we start using the source role >> then things will quickly change from object_r to system_r, so maybe the >> policy should do that anyway. Chris, any opinions on this? > > Yes, related object role would likely cause the least breakage. It > would preserve the existing default for existing filesystems (as they > already have object_r in the directory contexts), while allowing us to > switch over to the user's role for home directories upon a relabel or > new filesystem. Source role might create more conflicts, as we enforce > the role/type relationship for contexts and there might be a mismatch > between the creating process role and the parent directory type. > I am not sure where this is going, but I believe that separation based on role in the home directory is a mistake. It assumes that the home directory will always be used by the same user with the same role. And will not work when you have a network file system that supports labels. In Red Hat I can login to people.redhat.com people.fedoraproject.com which I should use the guest_r. While logging into my laptop I would be unconfined_t and on test machines I might get staff_r or user_r. All of them would use the same homedirectory. So how would this work in this environment? -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.8 (GNU/Linux) Comment: Using GnuPG with Fedora - http://enigmail.mozdev.org iEYEARECAAYFAkfqDU8ACgkQrlYvE4MpobPK2QCZARp10Z4BcqTHKGywNPo49F06 uJoAoLMYX3lHtyZkzDpS+BquTBFT4uoZ =/URn -----END PGP SIGNATURE----- -- This message was distributed to subscribers of the selinux mailing list. If you no longer wish to subscribe, send mail to majordomo@xxxxxxxxxxxxx with the words "unsubscribe selinux" without quotes as the message.
