Re: [libvirt] [PATCH] event: move event filtering to daemon (regression fix)

Commit f9f56340 for CVE-2014-0028 almost had the right idea - we need to check the ACL rules to filter which events to send. But it overlooked one thing: the event dispatch queue is running in the main loop thread, and therefore does not normally have a current virIdentityPtr. But filter checks can be based on current identity, so when libvirtd.conf contains access_drivers=["polkit"], we ended up rejecting access for EVERY event due to failure to look up the current identity, even if it should have been allowed. Furthermore, even for events that are triggered by API calls, it is important to remember that the point of events is that they can be copied across multiple connections, which may have separate identities and permissions. So even if events were dispatched from a context where we have an identity, we must change to the correct identity of the connection that will be receiving the event, rather than basing a decision on the context that triggered the event, when deciding whether to filter an event to a particular connection. If there were an easy way to get from virConnectPtr to the appropriate virIdentityPtr, then object_event.c could adjust the identity prior to checking whether to dispatch an event. But setting up that back-reference is a bit invasive. Instead, it is easier to delay the filtering check until lower down the stack, at the point where we have direct access to the RPC client object that owns an identity. As such, this patch ends up reverting a large portion of the framework of commit f9f56340. We also have to teach 'make check' to special-case the fact that the event registration filtering is done at the point of dispatch, rather than the point of registration. Note that even though we don't actually use virConnectDomainEventRegisterCheckACL (because the RegisterAny variant is sufficient), we still generate the function for the purposes of documenting that the filtering takes place. Also note that I did not entirely delete the notion of a filter from object_event.c; I still plan on using that for my upcoming patch series for qemu monitor events in libvirt-qemu.so. In other words, while this patch changes ACL filtering to live in remote.c and therefore we have no current client of the filtering in object_event.c, the notion of filtering in object_event.c is still useful down the road. * src/check-aclrules.pl: Exempt event registration from having to pass checkACL filter down call stack. * daemon/remote.c (remoteRelayDomainEventCheckACL) (remoteRelayNetworkEventCheckACL): New functions. (remoteRelay*Event*): Use new functions. * src/conf/domain_event.h (virDomainEventStateRegister) (virDomainEventStateRegisterID): Drop unused parameter. * src/conf/network_event.h (virNetworkEventStateRegisterID): Likewise. * src/conf/domain_event.c (virDomainEventFilter): Delete unused function. * src/conf/network_event.c (virNetworkEventFilter): Likewise. * src/libxl/libxl_driver.c: Adjust caller. * src/lxc/lxc_driver.c: Likewise. * src/network/bridge_driver.c: Likewise. * src/qemu/qemu_driver.c: Likewise. * src/remote/remote_driver.c: Likewise. * src/test/test_driver.c: Likewise. * src/uml/uml_driver.c: Likewise. * src/vbox/vbox_tmpl.c: Likewise. * src/xen/xen_driver.c: Likewise. Signed-off-by: Eric Blake <eblake(a)redhat.com&gt; --- daemon/remote.c | 257 ++++++++++++++++++++++++++++---------------- src/check-aclrules.pl | 7 +- src/conf/domain_event.c | 35 +----- src/conf/domain_event.h | 8 +- src/conf/network_event.c | 31 +----- src/conf/network_event.h | 6 +- src/libxl/libxl_driver.c | 2 - src/lxc/lxc_driver.c | 2 - src/network/bridge_driver.c | 1 - src/qemu/qemu_driver.c | 2 - src/remote/remote_driver.c | 4 +- src/test/test_driver.c | 6 +- src/uml/uml_driver.c | 2 - src/vbox/vbox_tmpl.c | 4 +- src/xen/xen_driver.c | 2 - 15 files changed, 188 insertions(+), 181 deletions(-)