On Thursday, December 06, 2012 06:29:54 PM Jason Wang wrote: > On Wednesday, December 05, 2012 03:26:19 PM Paul Moore wrote: > > This patch corrects some problems with LSM/SELinux that were introduced > > with the multiqueue patchset. The problem stems from the fact that the > > multiqueue work changed the relationship between the tun device and its > > associated socket; before the socket persisted for the life of the > > device, however after the multiqueue changes the socket only persisted > > for the life of the userspace connection (fd open). For non-persistent > > devices this is not an issue, but for persistent devices this can cause > > the tun device to lose its SELinux label. > > > > We correct this problem by adding an opaque LSM security blob to the > > tun device struct which allows us to have the LSM security state, e.g. > > SELinux labeling information, persist for the lifetime of the tun > > device. In the process we tweak the LSM hooks to work with this new > > approach to TUN device/socket labeling and introduce a new LSM hook, > > security_tun_dev_create_queue(), to approve requests to create a new > > TUN queue via TUNSETQUEUE. > > > > The SELinux code has been adjusted to match the new LSM hooks, the > > other LSMs do not make use of the LSM TUN controls. This patch makes > > use of the recently added "tun_socket:create_queue" permission to > > restrict access to the TUNSETQUEUE operation. On older SELinux > > policies which do not define the "tun_socket:create_queue" permission > > the access control decision for TUNSETQUEUE will be handled according > > to the SELinux policy's unknown permission setting. > > > > Signed-off-by: Paul Moore <pmoore@xxxxxxxxxx> ... > > @@ -4425,20 +4452,19 @@ static void selinux_tun_dev_post_create(struct > > sock > > *sk) * cause confusion to the TUN user that had no idea network labeling * > > protocols were being used */ > > > > - /* see the comments in selinux_tun_dev_create() about why we ... > > - > > - sksec->sid = current_sid(); > > + sksec->sid = tunsec->sid; > > Since both tun_set_iff() and tun_set_queue() would call this. I wonder when > it is called by tun_set_queue() we need some checking just like what we > done in v1, otherwise it's unconditionally in TUNSETQUEUE. Or we can add > them in selinux_tun_dev_create_queue()? In all the cases that call tun_attach() we have a new socket which needs to be labeled based on the tun->security label, yes? That is what the security_tun_dev_attach() code does, there is no need for access control at this point as the operation has already been authorized by either security_tun_dev_create() (new device), security_tun_dev_create_queue() (new queue), or security_tun_dev_open() (opening persistent device). I think we are all set, or am I missing something? > > sksec->sclass = SECCLASS_TUN_SOCKET; > > > > + > > + return 0; > > > > } -- paul moore security and virtualization @ redhat -- 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.
