On Fri, Mar 31, 2017 at 10:12:50AM -0400, James Carter wrote: > On 03/31/2017 10:10 AM, Stephen Smalley wrote: > > On Fri, 2017-03-31 at 15:59 +0200, Dominick Grift wrote: > > > On Fri, Mar 31, 2017 at 09:53:26AM -0400, Stephen Smalley wrote: > > > > On Fri, 2017-03-31 at 15:36 +0200, Dominick Grift wrote: > > > > > On Fri, Mar 31, 2017 at 09:30:56AM -0400, Stephen Smalley wrote: > > > > > > On Fri, 2017-03-31 at 09:25 -0400, Stephen Smalley wrote: > > > > > > > On Fri, 2017-03-31 at 14:09 +0200, Dominick Grift wrote: > > > > > > > > I vaguely recall that we discussed this issue or at least > > > > > > > > that > > > > > > > > i > > > > > > > > mentioned it here but i can't recall the outcome if any: > > > > > > > > > > > > > > > > So today on my rawhide system i noticed that i somehow > > > > > > > > forgot > > > > > > > > to > > > > > > > > add > > > > > > > > support for the smc_socket class (i suspect that is part of > > > > > > > > the > > > > > > > > extended socket class patches) > > > > > > > > > > > > > > > > I added the class (which i suppose is unordered like the > > > > > > > > othe > > > > > > > > extended socket classes) but as soon as I loaded up the > > > > > > > > policy > > > > > > > > with > > > > > > > > the new unordered smc_socket class the system became > > > > > > > > unusable. > > > > > > > > > > > > > > > > This is because the dbus object manager became confused due > > > > > > > > to > > > > > > > > my > > > > > > > > adding a new (unordered) class at runtime, and that the > > > > > > > > dbus > > > > > > > > class > > > > > > > > was no longer working. > > > > > > > > > > > > > > > > Modern systems heavily rely on dbus at the heart and so it > > > > > > > > is > > > > > > > > undesire-able that this happens. > > > > > > > > > > > > > > > > A reboot clears this issue up but adding (unordered) > > > > > > > > classes at > > > > > > > > runtime should not cause these issues i suspect > > > > > > > > > > > > > > dbusd doesn't use selinux_check_access() and therefore does > > > > > > > not > > > > > > > yet > > > > > > > support reordering of their classes/permissions at > > > > > > > runtime. The > > > > > > > same > > > > > > > is true of all userspace object managers created before > > > > > > > selinux_check_access() was introduced - anything that > > > > > > > directly > > > > > > > calls > > > > > > > security_compute_av() or avc_has_perm(). dbusd does call > > > > > > > selinux_set_mapping() at startup, so it can correctly handle > > > > > > > reordering of classes/permissions across restarts, but not > > > > > > > while > > > > > > > it > > > > > > > is > > > > > > > running. Calling selinux_set_mapping() again upon policy > > > > > > > reloads > > > > > > > (e.g. > > > > > > > from policy_reload_callback() if (event == > > > > > > > AVC_CALLBACK_RESET) > > > > > > > before > > > > > > > returning) may fix this problem, but requires proper > > > > > > > locking. Even > > > > > > > better would be to rid the dbusd selinux implementation of > > > > > > > threading > > > > > > > entirely, see https://bugs.freedesktop.org/show_bug.cgi?id=92 > > > > > > > 831# > > > > > > > c4 > > > > > > > > > > Thank you, I suppose i should take this to them then. > > > > > > > > No, someone who uses SELinux will need to develop a patch and test > > > > it > > > > for them; dbusd maintainer doesn't use SELinux himself. > > > > > > > > Looks like I'm also wrong about being able to call > > > > selinux_set_mapping() from an AVC callback, since > > > > selinux_set_mapping() > > > > itself calls avc_reset() to flush any cache entries before > > > > reloading > > > > the mapping, so that would produce infinite > > > > recursion. Sigh. Could > > > > change selinux_set_mapping() to not do that in libselinux, but that > > > > won't help on existing releases. Maybe we should just convert it > > > > over > > > > to using selinux_check_access() and drop all direct usage of the > > > > AVC. > > > > > > > > > > > > > > > > > > smc_socket was added by the kernel developers as part of the > > > > > > > merge > > > > > > > with > > > > > > > net-next since we now trigger a build failure in the kernel > > > > > > > if > > > > > > > any > > > > > > > new > > > > > > > address families are introduced without adding a > > > > > > > corresponding > > > > > > > security > > > > > > > class (so that SELinux always supports a separate class per > > > > > > > network > > > > > > > address family going forward). So there have been no policy > > > > > > > patches > > > > > > > submitted yet to define it in refpolicy even AFAIK. > > > > > > > > > > > > > > [1] https://github.com/SELinuxProject/selinux/issues/34 > > > > > > > > > > So i suppose its an unordered class? or do i have to order this > > > > > one > > > > > to avoid future issues? > > > > > > > > > > > > > > > > > BTW, I'm not sure what you did to trigger the problem. When I > > > > > > tested > > > > > > the extended socket classes, I added them to my running policy > > > > > > via > > > > > > a > > > > > > CIL module like this: > > > > > > > > > > Well i just added this commit (ignore the typo in the name) which > > > > > adds the new class to the unordered socket list > > > > > > > > > > https://github.com/DefenSec/dssp2-base/commit/5e3ada7d12525c8c659 > > > > > f347 > > > > > 863f09ec9caeceb56 > > > > > > > > > > then i built rpms using this script: > > > > > > > > > > https://github.com/DefenSec/dssp2-standard/blob/master/support/rp > > > > > m/ds > > > > > sp2-standard.sh > > > > > > > > > > and just rpm -Uvh the new rpm > > > > > > > > > > > > > > > > > (policycap extended_socket_class) > > > > > > > > > > > > (classcommon sctp_socket socket) > > > > > > (class sctp_socket (node_bind)) > > > > > > > > > > > > <snip> > > > > > > > > > > > > (classcommon qipcrtr_socket socket) > > > > > > (class qipcrtr_socket ()) > > > > > > > > > > > > (classorder (unordered sctp_socket icmp_socket ax25_socket > > > > > > ipx_socket > > > > > > netrom_socket bridge_socket atmpvc_socket x25_socket > > > > > > rose_socket > > > > > > decnet_socket atmsvc_socket rds_socket irda_socket pppox_socket > > > > > > llc_socket ib_socket mpls_socket can_socket tipc_socket > > > > > > bluetooth_socket iucv_socket rxrpc_socket isdn_socket > > > > > > phonet_socket > > > > > > ieee802154_socket caif_socket alg_socket nfc_socket > > > > > > vsock_socket > > > > > > kcm_socket qipcrtr_socket)) > > > > > > > > > > > > The classorder statement at the end ensured that they were > > > > > > appended > > > > > > to > > > > > > the end of the class list and therefore did not break anything. > > > > > > > > > > > > > > Looks like you failed to include a classorder statement for it as I > > > > did > > > > above. That's still required to avoid breaking legacy userspace > > > > object > > > > managers. > > > > > > > > > > > > > > No I added "scm_socket" (i renamed it later to smc_socket) to my list > > > or unordered classorder: > > > > > > ; > > > ; Class order of unordered Linux access vectors > > > ; > > > > > > (classorder > > > (unordered > > > alg_socket > > > atmpvc_socket > > > atmsvc_socket > > > ax25_socket > > > bluetooth_socket > > > caif_socket > > > can_socket > > > decnet_socket > > > icmp_socket > > > ieee802154_socket > > > ipx_socket > > > irda_socket > > > isdn_socket > > > iucv_socket > > > kcm_socket > > > llc_socket > > > netrom_socket > > > nfc_socket > > > phonet_socket > > > pppox_socket > > > qipcrtr_socket > > > rds_socket > > > rose_socket > > > rxrpc_socket > > > scm_socket > > > sctp_socket > > > tipc_socket > > > vsock_socket > > > x25_socket > > > ) > > > ) > > > > Then I'm confused as to why you encountered breakage. Doesn't CIL > > ensure that all of those classes are appended to the existing class > > list? In which case it won't disturb the dbus class definitions. > > If I would have left out the classorder entry , then a reboot would - i suppose - not have fixed the issue > > CIL appends unordered classes to the existing class list, so I am not sure > what is going on. > > Jim > > > > -- > James Carter <jwcart2@xxxxxxxxxxxxx> > National Security Agency -- Key fingerprint = 5F4D 3CDB D3F8 3652 FBD8 02D5 3B6C 5F1D 2C7B 6B02 https://sks-keyservers.net/pks/lookup?op=get&search=0x3B6C5F1D2C7B6B02 Dominick Grift
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