Commit Graph

97 Commits

Author SHA1 Message Date
Robert Watson
babe9a2bb3 Introduce p_canwait() and MAC Framework and MAC Policy entry points
mac_check_proc_wait(), which control the ability to wait4() specific
processes.  This permits MAC policies to limit information flow from
children that have changed label, although has to be handled carefully
due to common programming expectations regarding the behavior of
wait4().  The cr_seeotheruids() check in p_canwait() is #if 0'd for
this reason.

The mac_stub and mac_test policies are updated to reflect these new
entry points.

Sponsored by:	SPAWAR, SPARTA
Obtained from:	TrustedBSD Project
2005-04-18 13:36:57 +00:00
Robert Watson
7f53207b92 Introduce three additional MAC Framework and MAC Policy entry points to
control socket poll() (select()), fstat(), and accept() operations,
required for some policies:

        poll()          mac_check_socket_poll()
        fstat()         mac_check_socket_stat()
        accept()        mac_check_socket_accept()

Update mac_stub and mac_test policies to be aware of these entry points.
While here, add missing entry point implementations for:

        mac_stub.c      stub_check_socket_receive()
        mac_stub.c      stub_check_socket_send()
        mac_test.c      mac_test_check_socket_send()
        mac_test.c      mac_test_check_socket_visible()

Obtained from:	TrustedBSD Project
Sponsored by:	SPAWAR, SPARTA
2005-04-16 18:46:29 +00:00
Robert Watson
030a28b3b5 Introduce new MAC Framework and MAC Policy entry points to control the use
of system calls to manipulate elements of the process credential,
including:

        setuid()                mac_check_proc_setuid()
        seteuid()               mac_check_proc_seteuid()
        setgid()                mac_check_proc_setgid()
        setegid()               mac_check_proc_setegid()
        setgroups()             mac_check_proc_setgroups()
        setreuid()              mac_check_proc_setreuid()
        setregid()              mac_check_proc_setregid()
        setresuid()             mac_check_proc_setresuid()
        setresgid()             mac_check_rpoc_setresgid()

MAC checks are performed before other existing security checks; both
current credential and intended modifications are passed as arguments
to the entry points.  The mac_test and mac_stub policies are updated.

Submitted by:	Samy Al Bahra <samy@kerneled.org>
Obtained from:	TrustedBSD Project
2005-04-16 13:29:15 +00:00
Christian S.J. Peron
c92163dcad Move MAC check_vnode_mmap entry point out from being exclusive to
MAP_SHARED so that the entry point gets executed un-conditionally.
This may be useful for security policies which want to perform access
control checks around run-time linking.

-add the mmap(2) flags argument to the check_vnode_mmap entry point
 so that we can make access control decisions based on the type of
 mapped object.
-update any dependent API around this parameter addition such as
 function prototype modifications, entry point parameter additions
 and the inclusion of sys/mman.h header file.
-Change the MLS, BIBA and LOMAC security policies so that subject
 domination routines are not executed unless the type of mapping is
 shared. This is done to maintain compatibility between the old
 vm_mmap_vnode(9) and these policies.

Reviewed by:	rwatson
MFC after:	1 month
2005-04-14 16:03:30 +00:00
Robert Watson
c77cf2b162 Remove policy references to mpo_check_vnode_mprotect(), which is
currently unimplemented.

Update copyrights.

Pointed out by:	csjp
2005-01-26 23:43:32 +00:00
Robert Watson
ba53d9c937 Update mac_stub for MAC Framework policy entry points System V IPC
objects (message queues, semaphores, shared memory).

Submitted by:   Dandekar Hrishikesh <rishi_dandekar at sbcglobal dot net>
Obtained from:  TrustedBSD Project
Sponsored by:   DARPA, SPAWAR, McAfee Research
2005-01-22 20:26:43 +00:00
Robert Watson
2220907b6e Introduce a temporary mutex, mac_ifnet_mtx, to lock MAC labels on
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
2004-06-24 03:34:46 +00:00
Poul-Henning Kamp
89c9c53da0 Do the dreaded s/dev_t/struct cdev */
Bump __FreeBSD_version accordingly.
2004-06-16 09:47:26 +00:00
Pawel Jakub Dawidek
63dba32b76 Reimplement sysctls handling by MAC framework.
Now I believe it is done in the right way.

Removed some XXMAC cases, we now assume 'high' integrity level for all
sysctls, except those with CTLFLAG_ANYBODY flag set. No more magic.

Reviewed by:	rwatson
Approved by:	rwatson, scottl (mentor)
Tested with:	LINT (compilation), mac_biba(4) (functionality)
2004-02-22 12:31:44 +00:00
Robert Watson
f6a4109212 Update my personal copyrights and NETA copyrights in the kernel
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
2004-02-22 00:33:12 +00:00
Robert Watson
91c2dc9478 Commit file missed in last pass: MAC api uses 'struct pipepair', not
'struct pipe' now.
2004-02-01 21:52:09 +00:00
Robert Watson
2d92ec9858 Switch TCP over to using the inpcb label when responding in timed
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
2003-12-17 14:55:11 +00:00
Robert Watson
56d9e93207 Rename mac_create_cred() MAC Framework entry point to mac_copy_cred(),
and the mpo_create_cred() MAC policy entry point to
mpo_copy_cred_label().  This is more consistent with similar entry
points for creation and label copying, as mac_create_cred() was
called from crdup() as opposed to during process creation.  For
a number of policies, this removes the requirement for special
handling when copying credential labels, and improves consistency.

Approved by:	re (scottl)
Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, Network Associates Laboratories
2003-12-06 21:48:03 +00:00
Robert Watson
a557af222b Introduce a MAC label reference in 'struct inpcb', which caches
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
2003-11-18 00:39:07 +00:00
Robert Watson
b0323ea3aa Implement sockets support for __mac_get_fd() and __mac_set_fd()
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
2003-11-16 23:31:45 +00:00
Robert Watson
0196273b2d Implement mpo_copy_{mbuf,pipe,vnode}_label() entry points for
mac_stub and mac_test.

Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, Network Associates Laboratories
2003-11-16 18:28:58 +00:00
Robert Watson
64f00af879 Add stub entries for new MAC framework entry points:
mpo_reflect_mbuf_icmp()
  mpo_reflect_mbuf_tcp()
  mpo_check_vnode_deletextattr()
  mpo_check_vnode_listextattr()

Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, Network Associates Laboratories
2003-08-21 17:05:36 +00:00
Robert Watson
1c3f91cdc8 Generally rename things to represent the fact that this is now the
mac_stub policy and no longer mac_none (as found in the repocopy).
Add comment to this effect.

Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, Network Associates Laboratories
2003-08-21 16:22:52 +00:00
Robert Watson
f51e58036e Redesign the externalization APIs from the MAC Framework to
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
2003-06-23 01:26:34 +00:00
Robert Watson
78183ac2d2 Trim "trustedbsd_" from the front of the policy module "short names";
the vendor is only included in the long name currently, reducing
verbosity when modules are registered and unregistered.

Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, Network Associates Laboratories
2003-03-27 19:26:39 +00:00
Robert Watson
5e7ce4785f Modify the mac_init_ipq() MAC Framework entry point to accept an
additional flags argument to indicate blocking disposition, and
pass in M_NOWAIT from the IP reassembly code to indicate that
blocking is not OK when labeling a new IP fragment reassembly
queue.  This should eliminate some of the WITNESS warnings that
have started popping up since fine-grained IP stack locking
started going in; if memory allocation fails, the creation of
the fragment queue will be aborted.

Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, Network Associates Laboratories
2003-03-26 15:12:03 +00:00
Robert Watson
09de2dc22f Update MAC "none" stub policy to include stubs for the following
entry points:

  mac_none_thread_userret()
  mac_none_check_kenv_dump()
  mac_none_check_kenv_get()
  mac_none_check_kenv_set()
  mac_none_check_kenv_unset()
  mac_none_check_kld_load()
  mac_none_check_kld_stat()
  mac_none_check_kld_unload()
  mac_none_check_sysarch_ioperm()
  mac_none_check_system_acct()
  mac_none_check_system_settime()
  mac_none_check_system_swapoff()

Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, Network Associates Laboratories
2003-03-25 01:18:06 +00:00
Robert Watson
eba0370d90 Default policies to on: if you load them or compile them into your
kernel, you should expect them to do something, so now they do.  This
doesn't affect users who don't load or explicitly compile in the
policies.

Approved by:	re (jhb)
Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, Network Associates Laboratories
2002-12-10 16:20:34 +00:00
Robert Watson
990b4b2dc5 Remove dm_root entry from struct devfs_mount. It's never set, and is
unused.  Replace it with a dm_mount back-pointer to the struct mount
that the devfs_mount is associated with.  Export that pointer to MAC
Framework entry points, where all current policies don't use the
pointer.  This permits the SEBSD port of SELinux's FLASK/TE to compile
out-of-the-box on 5.0-CURRENT with full file system labeling support.

Approved by:	re (murray)
Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, Network Associates Laboratories
2002-12-09 03:44:28 +00:00
Robert Watson
63b6f478ec Garbage collect mac_create_devfs_vnode() -- it hasn't been used since
we brought in the new cache and locking model for vnode labels.  We
now rely on mac_associate_devfs_vnode().

Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, Network Associates Laboratories
2002-11-12 04:20:36 +00:00
Robert Watson
ef5def596d Update MAC modules for changes in arguments for exec MAC policy
entry points to include an explicit execlabel.

Approved by:	re
Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, Network Associates Laboratories
2002-11-08 18:04:36 +00:00
Robert Watson
939b97cba6 Update policy modules for changes in arguments associated with support
for label access on the interpreter, not just the shell script.  No
policies currently present in the system rely on the new labels.
2002-11-05 17:52:42 +00:00
Robert Watson
dc858fcabe License and wording updates: NAI has authorized the removal of clause
three from their BSD-style license.  Also, s/NAI Labs/Network Associates
Laboratories/.
2002-11-04 01:53:12 +00:00
Robert Watson
5c8dd34218 Move to C99 sparse structure initialization for the mac_policy_ops
structure definition, rather than using an operation vector
we translate into the structure.  Originally, we used a vector
for two reasons:

(1) We wanted to define the structure sparsely, which wasn't
    supported by the C compiler for structures.  For a policy
    with five entry points, you don't want to have to stick in
    a few hundred NULL function pointers.

(2) We thought it would improve ABI compatibility allowing modules
    to work with kernels that had a superset of the entry points
    defined in the module, even if the kernel had changed its
    entry point set.

Both of these no longer apply:

(1) C99 gives us a way to sparsely define a static structure.

(2) The ABI problems existed anyway, due to enumeration numbers,
    argument changes, and semantic mismatches.  Since the going
    rule for FreeBSD is that you really need your modules to
    pretty closely match your kernel, it's not worth the
    complexity.

This submit eliminates the operation vector, dynamic allocation
of the operation structure, copying of the vector to the
structure, and redoes the vectors in each policy to direct
structure definitions.  One enourmous benefit of this change
is that we now get decent type checking on policy entry point
implementation arguments.

Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, Network Associates Laboratories
2002-10-30 18:48:51 +00:00
Robert Watson
1979061b56 Various minor type, prototype tweaks -- clean up cruft due to lack of
type checking on entry points (to be introduced shortly).

Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, Network Associates Laboratories
2002-10-30 18:10:46 +00:00
Robert Watson
b914de36c0 While 'mode_t' seemed like a good idea for the access mode argument for
MAC access() and open() checks, the argument actually has an int type
where it becomes available.  Switch to using 'int' for the mode argument
throughout the MAC Framework and policy modules.

Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, Network Associates Laboratories
2002-10-30 17:56:57 +00:00
Robert Watson
927f6069ac Hook up no-op stubs for reboot, swapon, sysctl entry points.
Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, Network Associates Laboratories
2002-10-29 19:57:28 +00:00
Robert Watson
763bbd2f4f Slightly change the semantics of vnode labels for MAC: rather than
"refreshing" the label on the vnode before use, just get the label
right from inception.  For single-label file systems, set the label
in the generic VFS getnewvnode() code; for multi-label file systems,
leave the labeling up to the file system.  With UFS1/2, this means
reading the extended attribute during vfs_vget() as the inode is
pulled off disk, rather than hitting the extended attributes
frequently during operations later, improving performance.  This
also corrects sematics for shared vnode locks, which were not
previously present in the system.  This chances the cache
coherrency properties WRT out-of-band access to label data, but in
an acceptable form.  With UFS1, there is a small race condition
during automatic extended attribute start -- this is not present
with UFS2, and occurs because EAs aren't available at vnode
inception.  We'll introduce a work around for this shortly.

Approved by:	re
Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, Network Associates Laboratories
2002-10-26 14:38:24 +00:00
Robert Watson
24e8d0d07b Adapt MAC policies for the new user API changes; teach policies how
to parse their own label elements (some cleanup to occur here in the
future to use the newly added kernel strsep()).  Policies now
entirely encapsulate their notion of label in the policy module.

Approved by:	re
Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, Network Associates Laboratories
2002-10-22 14:31:34 +00:00
Robert Watson
57e2f49300 mac_none is a stub policy without any functional implementation.
Various cleanups, no functional changes:

	- Fix a type in an entry point stub, socket checks accept
	  sockets, not vnodes.
	- Trailing whitespace
	- Entry point sort order

Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, Network Associates Laboratories
2002-10-21 23:16:23 +00:00
Robert Watson
e183f80e54 Sync from MAC tree: break out the single mmap entry point into
seperate entry points for each occasion:

mac_check_vnode_mmap()		Check at initial mapping
mac_check_vnode_mprotect()	Check at mapping protection change
mac_check_vnode_mmap_downgrade()	Determine if a mapping downgrade
					should take place following
					subject relabel.

Implement mmap() and mprotect() entry points for labeled vnode
policies.  These entry points are currently not hooked up to the
VM system in the base tree.  These changes improve the consistency
of the access control interface and offer more flexibility regarding
limiting access to vnode mmaping.

Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, Network Associates Laboratories
2002-10-06 02:46:26 +00:00
Robert Watson
83985c267e Modify label allocation semantics for sockets: pass in soalloc's malloc
flags so that we can call malloc with M_NOWAIT if necessary, avoiding
potential sleeps while holding mutexes in the TCP syncache code.
Similar to the existing support for mbuf label allocation: if we can't
allocate all the necessary label store in each policy, we back out
the label allocation and fail the socket creation.  Sync from MAC tree.

Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, Network Associates Laboratories
2002-10-05 21:23:47 +00:00
Robert Watson
eea8ea3108 Implement mac_create_devfs_symlink() for policies that interact with
vnode labels.  Sync from MAC tree.

Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, Network Associates Laboratories
2002-10-05 18:56:25 +00:00
Robert Watson
c27b50f5b4 Merge implementation of mpo_check_vnode_link() for various appropriate
file-system aware MAC policies.  Sync to MAC tree.

Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, Network Associates Laboratories
2002-10-05 18:25:48 +00:00
Robert Watson
96adb90996 Begin another merge from the TrustedBSD MAC branch:
- Change mpo_init_foo(obj, label) and mpo_destroy_foo(obj, label) policy
  entry points to mpo_init_foo_label(label) and
  mpo_destroy_foo_label(label).  This will permit the use of the same
  entry points for holding temporary type-specific label during
  internalization and externalization, as well as for caching purposes.
- Because of this, break out mpo_{init,destroy}_socket() and
  mpo_{init,destroy}_mount() into seperate entry points for socket
  main/peer labels and mount main/fs labels.
- Since the prototype for label initialization is the same across almost
  all entry points, implement these entry points using common
  implementations for Biba, MLS, and Test, reducing the number of
  almost identical looking functions.

This simplifies policy implementation, as well as preparing us for the
merge of the new flexible userland API for managing labels on objects.

Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, Network Associates Laboratories
2002-10-05 15:10:00 +00:00
Robert Watson
740348c40a Prefer NULL to 0 when passing a NULL pointer. 2002-08-20 02:54:09 +00:00
Robert Watson
8a97ecf648 Provide stub mpo_syscall() implementations for mac_none and mac_test.
Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, NAI Labs
2002-08-20 02:53:35 +00:00
Robert Watson
177142e458 Pass active_cred and file_cred into the MAC framework explicitly
for mac_check_vnode_{poll,read,stat,write}().  Pass in fp->f_cred
when calling these checks with a struct file available.  Otherwise,
pass NOCRED.  All currently MAC policies use active_cred, but
could now offer the cached credential semantic used for the base
system security model.

Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, NAI Labs
2002-08-19 19:04:53 +00:00
Robert Watson
c024c3eeb1 Break out mac_check_pipe_op() into component check entry points:
mac_check_pipe_poll(), mac_check_pipe_read(), mac_check_pipe_stat(),
and mac_check_pipe_write().  This is improves consistency with other
access control entry points and permits security modules to only
control the object methods that they are interested in, avoiding
switch statements.

Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, NAI Labs
2002-08-19 16:59:37 +00:00
Robert Watson
7f724f8b51 Break out mac_check_vnode_op() into three seperate checks:
mac_check_vnode_poll(), mac_check_vnode_read(), mac_check_vnode_write().
This improves the consistency with other existing vnode checks, and
allows policies to avoid implementing switch statements to determine
what operations they do and do not want to authorize.

Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, NAI Labs
2002-08-19 16:43:25 +00:00
Robert Watson
fb95b5d3c3 Rename mac_check_socket_receive() to mac_check_socket_deliver() so that
we can use the names _receive() and _send() for the receive() and send()
checks.  Rename related constants, policy implementations, etc.

Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, NAI Labs
2002-08-15 18:51:27 +00:00
Robert Watson
d8a7b7a3cd Introduce support for Mandatory Access Control and extensible
kernel access control.

Provide implementations of some sample operating system security
policy extensions.  These are not yet hooked up to the build as
other infrastructure is still being committed.  Most of these
work fairly well and are in daily use in our development and (limited)
production environments.  Some are not yet in their final form,
and a number of the labeled policies waste a lot of kernel memory
and will be fixed over the next month or so to be more conservative.
They do give good examples of the flexibility of the MAC framework
for implementing a variety of security policies.

mac_biba:	Implementation of fixed-label Biba integrity policy,
		similar to those found in a number of commercial
		trusted operating systems.  All subjects and objects
		are assigned integrity levels, and information flow
		is controlled based on a read-up, write-down
		policy.  Currently, purely hierarchal.

mac_bsdextended:	Implementation of a "file system firewall",
		which allows the administrator to specify a series
		of rules limiting access by users and groups to
		objects owned by other users and groups.  This
		policy is unlabeled, relying on existing system
		security labeling (file permissions/ownership,
		process credentials).

mac_ifoff:	Secure interface silencing.  Special-purpose module
		to limit inappropriate out-going network traffic
		for silent monitoring scenarios.  Prevents the
		various network stacks from generating any output
		despite an interface being live for reception.

mac_mls:	Implementation of fixed-label Multi-Level Security
		confidentiality policy, similar to those found in
		a number of commercial trusted operating systems.
		All subjects and objects are assigned confidentiality
		levels, and information flow is controlled based on
		a write-up, read-down policy.  Currently, purely
		hiearchal, although non-hierarchal support is in the
		works.

mac_none:	Policy module implementing all MAC policy entry
		points with empty stubs.  A good place to start if
		you want all the prototypes types in for you, and
		don't mind a bit of pruning.  Can be loaded, but
		has no access control impact.  Useful also for
		performance measurements.

mac_seeotheruids:	Policy module implementing a security service
		similar to security.bsd.seeotheruids, only a slightly
		more detailed policy involving exceptions for members
		of specific groups, etc.  This policy is unlabeled,
		relying on existing system security labeling
		(process credentials).

mac_test:	Policy module implementing basic sanity tests for
		label handling.  Attempts to ensure that labels are
		not freed multiple times, etc, etc.

Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, NAI Labs
2002-07-31 18:07:45 +00:00