- Document some of the sysctl parameters. The read-only ones will go into

another subsection, but I'm not quite sure where yet.  Right now it's just
  the configurable bits.
- Move the label format off into another subsection to match other labeling
  policy man pages.
- Make the sample range label look like the form specified.

Sponsored by:	DARPA, Network Associates Laboratories
Obtained from:	TrustedBSD Project
This commit is contained in:
chris 2003-02-17 20:04:06 +00:00
parent 87f0991c93
commit efec3265b6

View File

@ -90,48 +90,6 @@ and
.Dq biba/low
none.
.Pp
Almost all system objects are tagged with a single, active label element,
reflecting the integrity of the object, or integrity of the data contained
in the object.
In general, objects labels are represented in the following form:
.Pp
.Dl biba/grade:compartments
.Pp
For example:
.Pp
.Bd -literal -offset indent
biba/10:2+3+6
biba/low
.Ed
.Pp
Subject labels consist of three label elements: a single (active) label,
as well as a range of available labels.
This range is represented using two ordered Biba label elements, and when set
on a process, permits the process to change its active label to any label of
greater or equal integrity to the low end of the range, and lesser or equal
integrity to the high end of the range.
In general, subject labels are represented in the following form:
.Pp
.Dl biba/singlegrade:singlecompartments(lograde:locompartments-
.Dl higrade:hicompartments)
.Pp
For example:
.Bd -literal -offset indent
biba/10:2+3+6(5-20:2+3+4+5+6)
biba/high(low-high)
.Ed
.Pp
Valid ranged labels must meet the following requirement regarding their
elements:
.Pp
.Dl rangehigh >= single >= rangelow
.Pp
One class of objects with ranges currently exists, the network interface.
In the case of the network interface, the single label element references the
default label for packets received over the interface, and the range
represents the range of acceptable labels of packets to be transmitted over
the interface.
.Pp
In general, Biba access control takes the following model:
.Bl -bullet
.It
@ -173,6 +131,70 @@ preventing the downward flow of information rather than the upward flow of
information.
Multi-Level Security (MLS) protects the confidentiality, rather than the
integrity, of subjects and objects.
.Ss Label Format
Almost all system objects are tagged with a single, active label element,
reflecting the integrity of the object, or integrity of the data contained
in the object.
In general, objects labels are represented in the following form:
.Pp
.Dl biba/grade:compartments
.Pp
For example:
.Pp
.Bd -literal -offset indent
biba/10:2+3+6
biba/low
.Ed
.Pp
Subject labels consist of three label elements: a single (active) label,
as well as a range of available labels.
This range is represented using two ordered Biba label elements, and when set
on a process, permits the process to change its active label to any label of
greater or equal integrity to the low end of the range, and lesser or equal
integrity to the high end of the range.
In general, subject labels are represented in the following form:
.Pp
.Dl biba/singlegrade:singlecompartments(lograde:locompartments-
.Dl higrade:hicompartments)
.Pp
For example:
.Bd -literal -offset indent
biba/10:2+3+6(5:2+3-20:2+3+4+5+6)
biba/high(low-high)
.Ed
.Pp
Valid ranged labels must meet the following requirement regarding their
elements:
.Pp
.Dl rangehigh >= single >= rangelow
.Pp
One class of objects with ranges currently exists, the network interface.
In the case of the network interface, the single label element references the
default label for packets received over the interface, and the range
represents the range of acceptable labels of packets to be transmitted over
the interface.
.Ss Runtime Configuration
The following
.Xr sysctl 8
MIBs are available for fine-tuning the enforcement of this MAC policy.
.Bl -tag -width 'security.mac.biba.ptys_equal'
.It Va security.mac.biba.enabled
Enables enforcement of the Biba integrity policy
(Default: 1)
.It Va security.mac.biba.ptys_equal
Label
.Sm off
.Xr pty 4
s
.Sm on
as
.Dq biba/equal
upon creation
(Default: 0)
.It Va security.mac.biba.revocation_enabled
Revoke access to objects if the label is changed to dominate the subject
(Default: 0)
.El
.Sh SEE ALSO
.Xr lomac 4 ,
.Xr mac 4 ,