improve performance:
- Eliminate custom reference count and condition variable to monitor
threads entering the framework, as this had both significant overhead
and behaved badly in the face of contention.
- Replace reference count with two locks: an rwlock and an sx lock,
which will be read-acquired by threads entering the framework
depending on whether a give policy entry point is permitted to sleep
or not.
- Replace previous mutex locking of the reference count for exclusive
access with write acquiring of both the policy list sx and rw locks,
which occurs only when policies are attached or detached.
- Do a lockless read of the dynamic policy list head before acquiring
any locks in order to reduce overhead when no dynamic policies are
loaded; this a race we can afford to lose.
- For every policy entry point invocation, decide whether sleeping is
permitted, and if not, use a _NOSLEEP() variant of the composition
macros, which will use the rwlock instead of the sxlock. In some
cases, we decide which to use based on allocation flags passed to the
MAC Framework entry point.
As with the move to rwlocks/rmlocks in pfil, this may trigger witness
warnings, but these should (generally) be false positives as all
acquisition of the locks is for read with two very narrow exceptions
for policy load/unload, and those code blocks should never acquire
other locks.
Sponsored by: Google, Inc.
Obtained from: TrustedBSD Project
Discussed with: csjp (idea, not specific patch)
privilege grants so that dtrace can be more easily used to monitor
the security decisions being generated by the MAC Framework following
policy invocation.
Successful access control checks will be reported by:
mac_framework:kernel:<entrypoint>:mac_check_ok
Failed access control checks will be reported by:
mac_framework:kernel:<entrypoint>:mac_check_err
Successful privilege grants will be reported by:
mac_framework:kernel:priv_grant:mac_grant_ok
Failed privilege grants will be reported by:
mac_framework:kernel:priv_grant:mac_grant_err
In all cases, the return value (always 0 for _ok, otherwise an errno
for _err) will be reported via arg0 on the probe, and subsequent
arguments will hold entrypoint-specific data, in a style similar to
privilege tracing.
Obtained from: TrustedBSD Project
Sponsored by: Google, Inc.
(1) Abstract interpreter vnode labeling in execve(2) and mac_execve(2)
so that the general exec code isn't aware of the details of
allocating, copying, and freeing labels, rather, simply passes in
a void pointer to start and stop functions that will be used by
the framework. This change will be MFC'd.
(2) Introduce a new flags field to the MAC_POLICY_SET(9) interface
allowing policies to declare which types of objects require label
allocation, initialization, and destruction, and define a set of
flags covering various supported object types (MPC_OBJECT_PROC,
MPC_OBJECT_VNODE, MPC_OBJECT_INPCB, ...). This change reduces the
overhead of compiling the MAC Framework into the kernel if policies
aren't loaded, or if policies require labels on only a small number
or even no object types. Each time a policy is loaded or unloaded,
we recalculate a mask of labeled object types across all policies
present in the system. Eliminate MAC_ALWAYS_LABEL_MBUF option as it
is no longer required.
MFC after: 1 week ((1) only)
Reviewed by: csjp
Obtained from: TrustedBSD Project
Sponsored by: Apple, Inc.
entry point, which is no longer required now that we don't support
old-style multicast tunnels. This removes the last mbuf object class
entry point that isn't init/copy/destroy.
Obtained from: TrustedBSD Project
Framework by moving from mac_mbuf_create_netlayer() to more specific
entry points for specific network services:
- mac_netinet_firewall_reply() to be used when replying to in-bound TCP
segments in pf and ipfw (etc).
- Rename mac_netinet_icmp_reply() to mac_netinet_icmp_replyinplace() and
add mac_netinet_icmp_reply(), reflecting that in some cases we overwrite
a label in place, but in others we apply the label to a new mbuf.
Obtained from: TrustedBSD Project
in the TrustedBSD MAC Framework:
- Add mac_atalk.c and add explicit entry point mac_netatalk_aarp_send()
for AARP packet labeling, rather than using a generic link layer
entry point.
- Add mac_inet6.c and add explicit entry point mac_netinet6_nd6_send()
for ND6 packet labeling, rather than using a generic link layer entry
point.
- Add expliict entry point mac_netinet_arp_send() for ARP packet
labeling, and mac_netinet_igmp_send() for IGMP packet labeling,
rather than using a generic link layer entry point.
- Remove previous genering link layer entry point,
mac_mbuf_create_linklayer() as it is no longer used.
- Add implementations of new entry points to various policies, largely
by replicating the existing link layer entry point for them; remove
old link layer entry point implementation.
- Make MAC_IFNET_LOCK(), MAC_IFNET_UNLOCK(), and mac_ifnet_mtx global
to the MAC Framework rather than static to mac_net.c as it is now
needed outside of mac_net.c.
Obtained from: TrustedBSD Project
we move towards netinet as a pseudo-object for the MAC Framework.
Rename 'mac_create_mbuf_linklayer' to 'mac_mbuf_create_linklayer' to
reflect general object-first ordering preference.
Sponsored by: SPARTA (original patches against Mac OS X)
Obtained from: TrustedBSD Project, Apple Computer
from Mac OS X Leopard--rationalize naming for entry points to
the following general forms:
mac_<object>_<method/action>
mac_<object>_check_<method/action>
The previous naming scheme was inconsistent and mostly
reversed from the new scheme. Also, make object types more
consistent and remove spaces from object types that contain
multiple parts ("posix_sem" -> "posixsem") to make mechanical
parsing easier. Introduce a new "netinet" object type for
certain IPv4/IPv6-related methods. Also simplify, slightly,
some entry point names.
All MAC policy modules will need to be recompiled, and modules
not updates as part of this commit will need to be modified to
conform to the new KPI.
Sponsored by: SPARTA (original patches against Mac OS X)
Obtained from: TrustedBSD Project, Apple Computer
variable name conventions for arguments passed into the framework --
for example, name network interfaces 'ifp', sockets 'so', mounts 'mp',
mbufs 'm', processes 'p', etc, wherever possible. Previously there
was significant variation in this regard.
Normalize copyright lists to ranges where sensible.
Framework and security modules, to src/sys/security/mac/mac_policy.h,
completing the removal of kernel-only MAC Framework include files from
src/sys/sys. Update the MAC Framework and MAC policy modules. Delete
the old mac_policy.h.
Third party policy modules will need similar updating.
Obtained from: TrustedBSD Project
subsystems will be a property of policy modules, which may require
access control check entry points to be invoked even when not actively
enforcing (i.e., to track information flow without providing
protection).
Obtained from: TrustedBSD Project
Suggested by: Christopher dot Vance at sparta dot com
than from the slab, but don't.
Document mac_mbuf_to_label(), mac_copy_mbuf_tag().
Clean up white space/wrapping for other comments.
Obtained from: TrustedBSD Project
the ifnet itself. The stack copy has been made while holding the mutex
protecting ifnet labels, so copying from the ifnet copy could result in
an inconsistent version being copied out.
Reported by: Todd.Miller@sparta.com
Obtained from: TrustedBSD Project
MFC after: 3 weeks
specific privilege names to a broad range of privileges. These may
require some future tweaking.
Sponsored by: nCircle Network Security, Inc.
Obtained from: TrustedBSD Project
Discussed on: arch@
Reviewed (at least in part) by: mlaier, jmg, pjd, bde, ceri,
Alex Lyashkov <umka at sevcity dot net>,
Skip Ford <skip dot ford at verizon dot net>,
Antoine Brodin <antoine dot brodin at laposte dot net>
begun with a repo-copy of mac.h to mac_framework.h. sys/mac.h now
contains the userspace and user<->kernel API and definitions, with all
in-kernel interfaces moved to mac_framework.h, which is now included
across most of the kernel instead.
This change is the first step in a larger cleanup and sweep of MAC
Framework interfaces in the kernel, and will not be MFC'd.
Obtained from: TrustedBSD Project
Sponsored by: SPARTA
other problems while labels were first being added to various kernel
objects. They have outlived their usefulness.
MFC after: 1 month
Suggested by: Christopher dot Vance at SPARTA dot com
Obtained from: TrustedBSD Project
redundant with respect to existing mbuf copy label routines. Expose
a new mac_copy_mbuf() routine at the top end of the Framework and
use that; use the existing mpo_copy_mbuf_label() routine on the
bottom end.
Obtained from: TrustedBSD Project
Sponsored by: SPARTA, SPAWAR
Approved by: re (scottl)
network interfaces. This global mutex will protect all ifnet labels.
Acquire the mutex across various MAC activities on interfaces, such
as security checks, propagating interface labels to mbufs generated
from the interface, retrieving and setting the interface label.
Introduce mpo_copy_ifnet_label MAC policy entry point to copy the
value of an interface label from one label to another. Use this
to avoid performing a label externalize while holding mac_ifnet_mtx;
copy the label to a temporary ifnet label and then externalize that.
Implement mpo_copy_ifnet_label for various MAC policies that
implement interface labeling using generic label copying routines.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, McAfee Research
lookup for the label tag fails, return NULL rather than something close
to NULL. This scenario occurs if mbuf header labeling is optional and
a policy requiring labeling is loaded, resulting in some mbufs having
labels and others not. Previously, 0x14 would be returned because the
NULL from m_tag_find() was not treated specially.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, McAfee Research
Assert the BPF descriptor lock in the MAC calls referencing live
BPF descriptors.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, McAfee Research
to a new mac_inet.c. This code is now conditionally compiled based
on inet support being compiled into the kernel.
Move socket related MAC Framework entry points from mac_net.c to a new
mac_socket.c.
To do this, some additional _enforce MIB variables are now non-static.
In addition, mbuf_to_label() is now mac_mbuf_to_label() and non-static.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, McAfee Research
to use the "year1-year3" format, as opposed to "year1, year2, year3".
This seems to make lawyers more happy, but also prevents the
lines from getting excessively long as the years start to add up.
Suggested by: imp
wait, rather than the socket label. This avoids reaching up to
the socket layer during connection close, which requires locking
changes. To do this, introduce MAC Framework entry point
mac_create_mbuf_from_inpcb(), which is called from tcp_twrespond()
instead of calling mac_create_mbuf_from_socket() or
mac_create_mbuf_netlayer(). Introduce MAC Policy entry point
mpo_create_mbuf_from_inpcb(), and implementations for various
policies, which generally just copy label data from the inpcb to
the mbuf. Assert the inpcb lock in the entry point since we
require consistency for the inpcb label reference.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
the MAC label referenced from 'struct socket' in the IPv4 and
IPv6-based protocols. This permits MAC labels to be checked during
network delivery operations without dereferencing inp->inp_socket
to get to so->so_label, which will eventually avoid our having to
grab the socket lock during delivery at the network layer.
This change introduces 'struct inpcb' as a labeled object to the
MAC Framework, along with the normal circus of entry points:
initialization, creation from socket, destruction, as well as a
delivery access control check.
For most policies, the inpcb label will simply be a cache of the
socket label, so a new protocol switch method is introduced,
pr_sosetlabel() to notify protocols that the socket layer label
has been updated so that the cache can be updated while holding
appropriate locks. Most protocols implement this using
pru_sosetlabel_null(), but IPv4/IPv6 protocols using inpcbs use
the the worker function in_pcbsosetlabel(), which calls into the
MAC Framework to perform a cache update.
Biba, LOMAC, and MLS implement these entry points, as do the stub
policy, and test policy.
Reviewed by: sam, bms
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
system calls, and prefer these calls over getsockopt()/setsockopt()
for ABI reasons. When addressing UNIX domain sockets, these calls
retrieve and modify the socket label, not the label of the
rendezvous vnode.
- Create mac_copy_socket_label() entry point based on
mac_copy_pipe_label() entry point, intended to copy the socket
label into temporary storage that doesn't require a socket lock
to be held (currently Giant).
- Implement mac_copy_socket_label() for various policies.
- Expose socket label allocation, free, internalize, externalize
entry points as non-static from mac_net.c.
- Use mac_socket_label_set() in __mac_set_fd().
MAC-aware applications may now use mac_get_fd(), mac_set_fd(), and
mac_get_peer() to retrieve and set various socket labels without
directly invoking the getsockopt() interface.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
mac_setsockopt_label() into mac_socket_label_set(); make it non-static
so that it can be invoked from kern_mac.c for mac_set_fd().
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
in various kernel objects to represent security data, we embed a
(struct label *) pointer, which now references labels allocated using
a UMA zone (mac_label.c). This allows the size and shape of struct
label to be varied without changing the size and shape of these kernel
objects, which become part of the frozen ABI with 5-STABLE. This opens
the door for boot-time selection of the number of label slots, and hence
changes to the bound on the number of simultaneous labeled policies
at boot-time instead of compile-time. This also makes it easier to
embed label references in new objects as required for locking/caching
with fine-grained network stack locking, such as inpcb structures.
This change also moves us further in the direction of hiding the
structure of kernel objects from MAC policy modules, not to mention
dramatically reducing the number of '&' symbols appearing in both the
MAC Framework and MAC policy modules, and improving readability.
While this results in minimal performance change with MAC enabled, it
will observably shrink the size of a number of critical kernel data
structures for the !MAC case, and should have a small (but measurable)
performance benefit (i.e., struct vnode, struct socket) do to memory
conservation and reduced cost of zeroing memory.
NOTE: Users of MAC must recompile their kernel and all MAC modules as a
result of this change. Because this is an API change, third party
MAC modules will also need to be updated to make less use of the '&'
symbol.
Suggestions from: bmilekic
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
successfully initialized in the label as a socket peer label, not a
socket label. For current policy modules, this didn't make a
difference, but if a policy module had label data in the peer label
that was to be GC'd in a different way than the normal socket label,
it might have been a problem.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
type, rather than "object_label" as the first argument. This reduces
complexity a little for the consumer, and also makes it easier for
use to rename the underlying entry points in struct mac_policy_obj.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
Network and socket enforcement toggles.
Counters for network objects (mbufs, ifnets, bpfdecs, sockets, and ipqs).
Label management routines for network objects.
Life cycle events for network objects.
Label internalization/externalization/relabel for ifnets, sockets,
including ioctl implementations for sockets, ifnets.
Access control checks relating to network obejcts.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
mac_reflect_mbuf_icmp()
mac_reflect_mbuf_tcp()
These entry points permit MAC policies to do "update in place"
changes to the labels on ICMP and TCP mbuf headers when an ICMP or
TCP response is generated to a packet outside of the context of
an existing socket. For example, in respond to a ping or a RST
packet to a SYN on a closed port.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
explicit access control checks to delete and list extended attributes
on a vnode, rather than implicitly combining with the setextattr and
getextattr checks. This reflects EA API changes in the kernel made
recently, including the move to explicit VOP's for both of these
operations.
Obtained from: TrustedBSD PRoject
Sponsored by: DARPA, Network Associates Laboratories
MAC_DEBUG_COUNTER_INC() and MAC_DEBUG_COUNTER_DEC() to maintain
debugging counter values rather than #ifdef'ing the atomic
operations to MAC_DEBUG.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
the MAC policy modules to improve robustness against C string
bugs and vulnerabilities. Following these revisions, all
string construction of labels for export to userspace (or
elsewhere) is performed using the sbuf API, which prevents
the consumer from having to perform laborious and intricate
pointer and buffer checks. This substantially simplifies
the externalization logic, both at the MAC Framework level,
and in individual policies; this becomes especially useful
when policies export more complex label data, such as with
compartments in Biba and MLS.
Bundled in here are some other minor fixes associated with
externalization: including avoiding malloc while holding the
process mutex in mac_lomac, and hence avoid a failure mode
when printing labels during a downgrade operation due to
the removal of the M_NOWAIT case.
This has been running in the MAC development tree for about
three weeks without problems.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
Several of the subtypes have an associated vnode which is used for
stuff like the f*() functions.
By giving the vnode a speparate field, a number of checks for the specific
subtype can be replaced simply with a check for f_vnode != NULL, and
we can later free f_data up to subtype specific use.
At this point in time, f_data still points to the vnode, so any code I
might have overlooked will still work.
constants in question refer to the number of label slots, not the
maximum number of policies that may be loaded. This should reduce
confusion regarding an element in the MAC sysctl MIB, as well as
make it more clear what the affect of changing the compile-time
constants is.
Approved by: re (jhb)
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
(1) Accept that we're now going to use mutexes, so don't attempt
to avoid treating them as mutexes. This cleans up locking
accessor function names some.
(2) Rename variables to _mtx, _cv, _count, simplifying the naming.
(3) Add a new form of the _busy() primitive that conditionally
makes the list busy: if there are entries on the list, bump
the busy count. If there are no entries, don't bump the busy
count. Return a boolean indicating whether or not the busy
count was bumped.
(4) Break mac_policy_list into two lists: one with the same name
holding dynamic policies, and a new list, mac_static_policy_list,
which holds policies loaded before mac_late and without the
unload flag set. The static list may be accessed without
holding the busy count, since it can't change at run-time.
(5) In general, prefer making the list busy conditionally, meaning
we pay only one mutex lock per entry point if all modules are
on the static list, rather than two (since we don't have to
lower the busy count when we're done with the framework). For
systems running just Biba or MLS, this will halve the mutex
accesses in the network stack, and may offer a substantial
performance benefits.
(6) Lay the groundwork for a dynamic-free kernel option which
eliminates all locking associated with dynamically loaded or
unloaded policies, for pre-configured systems requiring
maximum performance but less run-time flexibility.
These changes have been running for a few weeks on MAC development
branch systems.
Approved by: re (jhb)
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
- Add a parameter to vm_pageout_flush() that tells vm_pageout_flush()
whether its caller has locked the vm_object. (This is a temporary
measure to bootstrap vm_object locking.)
don't try and convert the argument flags to malloc flags, or we risk
implicitly requesting blocking and generating witness warnings.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
returning some additional room in the first mbuf in a chain, and
avoiding feature-specific contents in the mbuf header. To do this:
- Modify mbuf_to_label() to extract the tag, returning NULL if not
found.
- Introduce mac_init_mbuf_tag() which does most of the work
mac_init_mbuf() used to do, except on an m_tag rather than an
mbuf.
- Scale back mac_init_mbuf() to perform m_tag allocation and invoke
mac_init_mbuf_tag().
- Replace mac_destroy_mbuf() with mac_destroy_mbuf_tag(), since
m_tag's are now GC'd deep in the m_tag/mbuf code rather than
at a higher level when mbufs are directly free()'d.
- Add mac_copy_mbuf_tag() to support m_copy_pkthdr() and related
notions.
- Generally change all references to mbuf labels so that they use
mbuf_to_label() rather than &mbuf->m_pkthdr.label. This
required no changes in the MAC policies (yay!).
- Tweak mbuf release routines to not call mac_destroy_mbuf(),
tag destruction takes care of it for us now.
- Remove MAC magic from m_copy_pkthdr() and m_move_pkthdr() --
the existing m_tag support does all this for us. Note that
we can no longer just zero the m_tag list on the target mbuf,
rather, we have to delete the chain because m_tag's will
already be hung off freshly allocated mbuf's.
- Tweak m_tag copying routines so that if we're copying a MAC
m_tag, we don't do a binary copy, rather, we initialize the
new storage and do a deep copy of the label.
- Remove use of MAC_FLAG_INITIALIZED in a few bizarre places
having to do with mbuf header copies previously.
- When an mbuf is copied in ip_input(), we no longer need to
explicitly copy the label because it will get handled by the
m_tag code now.
- No longer any weird handling of MAC labels in if_loop.c during
header copies.
- Add MPC_LOADTIME_FLAG_LABELMBUFS flag to Biba, MLS, mac_test.
In mac_test, handle the label==NULL case, since it can be
dynamically loaded.
In order to improve performance with this change, introduce the notion
of "lazy MAC label allocation" -- only allocate m_tag storage for MAC
labels if we're running with a policy that uses MAC labels on mbufs.
Policies declare this intent by setting the MPC_LOADTIME_FLAG_LABELMBUFS
flag in their load-time flags field during declaration. Note: this
opens up the possibility of post-boot policy modules getting back NULL
slot entries even though they have policy invariants of non-NULL slot
entries, as the policy might have been loaded after the mbuf was
allocated, leaving the mbuf without label storage. Policies that cannot
handle this case must be declared as NOTLATE, or must be modified.
- mac_labelmbufs holds the current cumulative status as to whether
any policies require mbuf labeling or not. This is updated whenever
the active policy set changes by the function mac_policy_updateflags().
The function iterates the list and checks whether any have the
flag set. Write access to this variable is protected by the policy
list; read access is currently not protected for performance reasons.
This might change if it causes problems.
- Add MAC_POLICY_LIST_ASSERT_EXCLUSIVE() to permit the flags update
function to assert appropriate locks.
- This makes allocation in mac_init_mbuf() conditional on the flag.
Reviewed by: sam
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
mbuf_to_label(). This permits the vast majority of entry point code
to be unaware that labels are stored in m->m_pkthdr.label, such that
we can experiment storage of labels elsewhere (such as in m_tags).
Reviewed by: sam
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
