selinux: default_range glblub implementation

A policy developer can now specify glblub as a default_range default and
the computed transition will be the intersection of the mls range of
the two contexts.

The glb (greatest lower bound) lub (lowest upper bound) of a range is calculated
as the greater of the low sensitivities and the lower of the high sensitivities
and the and of each category bitmap.

This can be used by MLS solution developers to compute a context that satisfies,
for example, the range of a network interface and the range of a user logging in.

Some examples are:

User Permitted Range | Network Device Label | Computed Label
---------------------|----------------------|----------------
s0-s1:c0.c12         | s0                   | s0
s0-s1:c0.c12         | s0-s1:c0.c1023       | s0-s1:c0.c12
s0-s4:c0.c512        | s1-s1:c0.c1023       | s1-s1:c0.c512
s0-s15:c0,c2         | s4-s6:c0.c128        | s4-s6:c0,c2
s0-s4                | s2-s6                | s2-s4
s0-s4                | s5-s8                | INVALID
s5-s8                | s0-s4                | INVALID

Signed-off-by: Joshua Brindle <joshua.brindle@crunchydata.com>
[PM: subject lines and checkpatch.pl fixes]
Signed-off-by: Paul Moore <paul@paul-moore.com>
This commit is contained in:
Joshua Brindle
2019-09-04 14:03:23 -07:00
committed by Paul Moore
parent 3e3e24b420
commit 42345b68c2
7 changed files with 62 additions and 1 deletions

View File

@@ -40,10 +40,11 @@
#define POLICYDB_VERSION_CONSTRAINT_NAMES 29
#define POLICYDB_VERSION_XPERMS_IOCTL 30
#define POLICYDB_VERSION_INFINIBAND 31
#define POLICYDB_VERSION_GLBLUB 32
/* Range of policy versions we understand*/
#define POLICYDB_VERSION_MIN POLICYDB_VERSION_BASE
#define POLICYDB_VERSION_MAX POLICYDB_VERSION_INFINIBAND
#define POLICYDB_VERSION_MAX POLICYDB_VERSION_GLBLUB
/* Mask for just the mount related flags */
#define SE_MNTMASK 0x0f