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=92831#c4 Thank you, I suppose i should take this to them then. > > > > 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/5e3ada7d12525c8c659f347863f09ec9caeceb56 then i built rpms using this script: https://github.com/DefenSec/dssp2-standard/blob/master/support/rpm/dssp2-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. > -- 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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